Decreased femoral arterial flow during simulated microgravity in the rat

NASA Technical Reports Server (NTRS)

Roer, Robert D.; Dillaman, Richard M.

1994-01-01

To determine whether the blood supply to the hindlimbs of rats is altered by the tail-suspension model of weightlessness, rats were chronically instrumented for the measurement of femoral artery flow. Ultrasonic transit-time flow probes were implanted into 8-wk-old Wistar-Furth rats under ketamine-xylazine anesthesia, and, after 24 h of recovery, flow was measured in the normal ambulatory posture. Next, rats were suspended and flow was measured immediately and then daily over the next 4-7 days. Rats were subsequently returned to normal posture, and flow was monitored daily for 1-3 days. Mean arterial flow decreased immediately on the rats being suspensed and continued to decrease until a new steady state of approximately 60% of control values was attained at 5 days. On the rats returning to normal posture, flow increased to levels observed before suspension. Quantile-quantile plots of blood flow data revealed a decrease in flow during both systole and diastole. The observed decrease in hindlimb blood flow during suspension suggests a possible role in the etiology of muscular atrophy and bone loss in microgravity.

[Quantitative estimation of evapotranspiration from Tahe forest ecosystem, Northeast China].

PubMed

Qu, Di; Fan, Wen-Yi; Yang, Jin-Ming; Wang, Xu-Peng

2014-06-01

Evapotranspiration (ET) is an important parameter of agriculture, meteorology and hydrology research, and also an important part of the global hydrological cycle. This paper applied the improved DHSVM distributed hydrological model to estimate daily ET of Tahe area in 2007 using leaf area index and other surface data extracted TM remote sensing data, and slope, aspect and other topographic indices obtained by using the digital elevation model. The relationship between daily ET and daily watershed outlet flow was built by the BP neural network, and a water balance equation was established for the studied watershed, together to test the accuracy of the estimation. The results showed that the model could be applied in the study area. The annual total ET of Tahe watershed was 234.01 mm. ET had a significant seasonal variation. The ET had the highest value in summer and the average daily ET value was 1.56 mm. The average daily ET in autumn and spring were 0.30, 0.29 mm, respectively, and winter had the lowest ET value. Land cover type had a great effect on ET value, and the broadleaf forest had a higher ET ability than the mixed forest, followed by the needle leaf forest.

PFReports: A program for systematic checking of annual peaks in NWISWeb

USGS Publications Warehouse

Ryberg, Karen R.

2008-01-01

The accuracy, characterization, and completeness of the U.S. Geological Survey (USGS) peak-flow data drive the determination of flood-frequency estimates that are used daily to design water and transportation infrastructure, delineate flood-plain boundaries, and regulate development and utilization of lands throughout the Nation and are essential to understanding the implications of climate change on flooding. Indeed, this high-profile database reflects and highlights the quality of USGS water-data collection programs. Its extension and improvement are essential to efforts to strengthen USGS networks and science leadership and is worthy of the attention of Water Science Center (WSC) hydrographers. This document describes a computer program, PFReports, and its output that facilitates efficient and robust review and correction of data in the USGS Peak Flow File (PFF) hosted as part of NWISWeb (the USGS public Web interface to much of the data stored and managed within the National Water Information System or NWIS). Checks embedded in the program are recommended as part of a more comprehensive assessment of peak flow data that will eventually include examination of possible regional changes, seasonal changes, and decadal variations in magnitude, timing, and frequency. Just as important as the comprehensive assessment, cleaning up the database will increase the likelihood of improved WSC regional flood-frequency equations. As an example of the value of cleaning up the PFF, data for 26,921 sites in the PFF were obtained. Of those sites, 17,542 sites had peak streamflow values and daily values. For the 17,542 sites, 1,097 peaks were identified that were less than the daily value for the day on which the peak occurred. Of the 26,921 sites, 11,643 had peak streamflow values, concurrent daily values, and at least 10 peaks. At the 11,643 sites, 2,205 peaks were identified as potential outliers in a regression of peak streamflows on daily values. Previous efforts to identify problems with the PFF were time consuming, laborious, and often ineffective. This new suite of checks represents an effort to automate identification of specific problems without plotting or printing large amounts of data that may not have problems. In addition, the results of the checks of the peak flow files are delivered through the World Wide Web with links to individual reports so that WSCs can focus on specific problems in an organized and standardized fashion. Over the years, technical reviews, regional-flood studies, and user inquiries have identified many minor and some major problems in the PFF. However, the cumbersome nature of the PFF editor and a lack of analytical tools have hampered efforts at quality assurance/quality control (QA/QC) and subsequently to make needed revisions to the database. This document is organized to provide information regarding PFReports, especially those tests involving regression and to provide an overview of the review procedures for utilizing the output. It also may be used as a reference for the data qualification codes and abbreviations for the tests. Results of the checks for all peak flow files (March 2008) are available at http://nd.water.usgs.gov/internal/pfreports/.

A precipitation-runoff model for simulating natural streamflow conditions in the Smith River watershed, Montana, water years 1996-2008

USGS Publications Warehouse

Chase, Katherine J.; Caldwell, Rodney R.; Stanley, Andrea K.

2014-01-01

This report documents the construction of a precipitation-runoff model for simulating natural streamflow in the Smith River watershed, Montana. This Precipitation-Runoff Modeling System model, constructed in cooperation with the Meagher County Conservation District, can be used to examine the general hydrologic framework of the Smith River watershed, including quantification of precipitation, evapotranspiration, and streamflow; partitioning of streamflow between surface runoff and subsurface flow; and quantifying contributions to streamflow from several parts of the watershed. The model was constructed by using spatial datasets describing watershed topography, the streams, and the hydrologic characteristics of the basin soils and vegetation. Time-series data (daily total precipitation, and daily minimum and maximum temperature) were input to the model to simulate daily streamflow. The model was calibrated for water years 2002–2007 and evaluated for water years 1996–2001. Though water year 2008 was included in the study period to evaluate water-budget components, calibration and evaluation data were unavailable for that year. During the calibration and evaluation periods, simulated-natural flow values were compared to reconstructed-natural streamflow data. These reconstructed-natural streamflow data were calculated by adding Bureau of Reclamation’s depletions data to the observed streamflows. Reconstructed-natural streamflows represent estimates of streamflows for water years 1996–2007 assuming there was no agricultural water-resources development in the watershed. Additional calibration targets were basin mean monthly solar radiation and potential evapotranspiration. The model estimated the hydrologic processes in the Smith River watershed during the calibration and evaluation periods. Simulated-natural mean annual and mean monthly flows generally were the same or higher than the reconstructed-natural streamflow values during the calibration period, whereas they were lower during the evaluation period. The shape of the annual hydrographs for the simulated-natural daily streamflow values matched the shape of the hydrographs for the reconstructed-natural values for most of the calibration period, but daily streamflow values were underestimated during the evaluation period for water years 1996–1998. The model enabled a detailed evaluation of the components of the water budget within the Smith River watershed during the water year 1996–2008 study period. During this study period, simulated mean annual precipitation across the Smith River watershed was 16 inches, out of which 14 inches evaporated or transpired and 2 inches left the basin as streamflow. Per the precipitation-runoff model simulations, during most of the year, surface runoff rarely (less than 2 percent of the time during water years 2002–2008) makes up more than 10 percent of the total streamflow. Subsurface flow (the combination of interflow and groundwater flow) makes up most of the total streamflow (99 or more percent of total streamflow for 71 percent of the time during water years 2002–2008).

Daily values flow comparison and estimates using program HYCOMP, version 1.0

USGS Publications Warehouse

Sanders, Curtis L.

2002-01-01

A method used by the U.S. Geological Survey for quality control in computing daily value flow records is to compare hydrographs of computed flows at a station under review to hydrographs of computed flows at a selected index station. The hydrographs are placed on top of each other (as hydrograph overlays) on a light table, compared, and missing daily flow data estimated. This method, however, is subjective and can produce inconsistent results, because hydrographers can differ when calculating acceptable limits of deviation between observed and estimated flows. Selection of appropriate index stations also is judgemental, giving no consideration to the mathematical correlation between the review station and the index station(s). To address the limitation of the hydrograph overlay method, a set of software programs, written in the SAS macrolanguage, was developed and designated Program HYDCOMP. The program automatically selects statistically comparable index stations by correlation and regression, and performs hydrographic comparisons and estimates of missing data by regressing daily mean flows at the review station against -8 to +8 lagged flows at one or two index stations and day-of-week. Another advantage that HYDCOMP has over the graphical method is that estimated flows, the criteria for determining the quality of the data, and the selection of index stations are determined statistically, and are reproducible from one user to another. HYDCOMP will load the most-correlated index stations into another file containing the ?best index stations,? but will not overwrite stations already in the file. A knowledgeable user should delete unsuitable index stations from this file based on standard error of estimate, hydrologic similarity of candidate index stations to the review station, and knowledge of the individual station characteristics. Also, the user can add index stations not selected by HYDCOMP, if desired. Once the file of best-index stations is created, a user may do hydrographic comparison and data estimates by entering the number of the review station, selecting an index station, and specifying the periods to be used for regression and plotting. For example, the user can restrict the regression to ice-free periods of the year to exclude flows estimated during iced conditions. However, the regression could still be used to estimate flow during iced conditions. HYDCOMP produces the standard error of estimate as a measure of the central scatter of the regression and R-square (coefficient of determination) for evaluating the accuracy of the regression. Output from HYDCOMP includes plots of percent residuals against (1) time within the regression and plot periods, (2) month and day of the year for evaluating seasonal bias in the regression, and (3) the magnitude of flow. For hydrographic comparisons, it plots 2-month segments of hydrographs over the selected plot period showing the observed flows, the regressed flows, the 95 percent confidence limit flows, flow measurements, and regression limits. If the observed flows at the review station remain outside the 95 percent confidence limits for a prolonged period, there may be some error in the flows at the review station or at the index station(s). In addition, daily minimum and maximum temperatures and daily rainfall are shown on the hydrographs, if available, to help indicate whether an apparent change in flow may result from rainfall or from changes in backwater from melting ice or freezing water. HYDCOMP statistically smooths estimated flows from non-missing flows at the edges of the gaps in data into regressed flows at the center of the gaps using the Kalman smoothing algorithm. Missing flows are automatically estimated by HYDCOMP, but the user also can specify that periods of erroneous, but nonmissing flows, be estimated by the program.

Statistical Approaches for Spatiotemporal Prediction of Low Flows

NASA Astrophysics Data System (ADS)

Fangmann, A.; Haberlandt, U.

2017-12-01

An adequate assessment of regional climate change impacts on streamflow requires the integration of various sources of information and modeling approaches. This study proposes simple statistical tools for inclusion into model ensembles, which are fast and straightforward in their application, yet able to yield accurate streamflow predictions in time and space. Target variables for all approaches are annual low flow indices derived from a data set of 51 records of average daily discharge for northwestern Germany. The models require input of climatic data in the form of meteorological drought indices, derived from observed daily climatic variables, averaged over the streamflow gauges' catchments areas. Four different modeling approaches are analyzed. Basis for all pose multiple linear regression models that estimate low flows as a function of a set of meteorological indices and/or physiographic and climatic catchment descriptors. For the first method, individual regression models are fitted at each station, predicting annual low flow values from a set of annual meteorological indices, which are subsequently regionalized using a set of catchment characteristics. The second method combines temporal and spatial prediction within a single panel data regression model, allowing estimation of annual low flow values from input of both annual meteorological indices and catchment descriptors. The third and fourth methods represent non-stationary low flow frequency analyses and require fitting of regional distribution functions. Method three is subject to a spatiotemporal prediction of an index value, method four to estimation of L-moments that adapt the regional frequency distribution to the at-site conditions. The results show that method two outperforms successive prediction in time and space. Method three also shows a high performance in the near future period, but since it relies on a stationary distribution, its application for prediction of far future changes may be problematic. Spatiotemporal prediction of L-moments appeared highly uncertain for higher-order moments resulting in unrealistic future low flow values. All in all, the results promote an inclusion of simple statistical methods in climate change impact assessment.

Climate change effects on extreme flows of water supply area in Istanbul: utility of regional climate models and downscaling method.

PubMed

Kara, Fatih; Yucel, Ismail

2015-09-01

This study investigates the climate change impact on the changes of mean and extreme flows under current and future climate conditions in the Omerli Basin of Istanbul, Turkey. The 15 regional climate model output from the EU-ENSEMBLES project and a downscaling method based on local implications from geophysical variables were used for the comparative analyses. Automated calibration algorithm is used to optimize the parameters of Hydrologiska Byråns Vattenbalansavdel-ning (HBV) model for the study catchment using observed daily temperature and precipitation. The calibrated HBV model was implemented to simulate daily flows using precipitation and temperature data from climate models with and without downscaling method for reference (1960-1990) and scenario (2071-2100) periods. Flood indices were derived from daily flows, and their changes throughout the four seasons and year were evaluated by comparing their values derived from simulations corresponding to the current and future climate. All climate models strongly underestimate precipitation while downscaling improves their underestimation feature particularly for extreme events. Depending on precipitation input from climate models with and without downscaling the HBV also significantly underestimates daily mean and extreme flows through all seasons. However, this underestimation feature is importantly improved for all seasons especially for spring and winter through the use of downscaled inputs. Changes in extreme flows from reference to future increased for the winter and spring and decreased for the fall and summer seasons. These changes were more significant with downscaling inputs. With respect to current time, higher flow magnitudes for given return periods will be experienced in the future and hence, in the planning of the Omerli reservoir, the effective storage and water use should be sustained.

Bayesian forecasting and uncertainty quantifying of stream flows using Metropolis-Hastings Markov Chain Monte Carlo algorithm

NASA Astrophysics Data System (ADS)

Wang, Hongrui; Wang, Cheng; Wang, Ying; Gao, Xiong; Yu, Chen

2017-06-01

This paper presents a Bayesian approach using Metropolis-Hastings Markov Chain Monte Carlo algorithm and applies this method for daily river flow rate forecast and uncertainty quantification for Zhujiachuan River using data collected from Qiaotoubao Gage Station and other 13 gage stations in Zhujiachuan watershed in China. The proposed method is also compared with the conventional maximum likelihood estimation (MLE) for parameter estimation and quantification of associated uncertainties. While the Bayesian method performs similarly in estimating the mean value of daily flow rate, it performs over the conventional MLE method on uncertainty quantification, providing relatively narrower reliable interval than the MLE confidence interval and thus more precise estimation by using the related information from regional gage stations. The Bayesian MCMC method might be more favorable in the uncertainty analysis and risk management.

Emerging interdependence between stock values during financial crashes.

PubMed

Rocchi, Jacopo; Tsui, Enoch Yan Lok; Saad, David

2017-01-01

To identify emerging interdependencies between traded stocks we investigate the behavior of the stocks of FTSE 100 companies in the period 2000-2015, by looking at daily stock values. Exploiting the power of information theoretical measures to extract direct influences between multiple time series, we compute the information flow across stock values to identify several different regimes. While small information flows is detected in most of the period, a dramatically different situation occurs in the proximity of global financial crises, where stock values exhibit strong and substantial interdependence for a prolonged period. This behavior is consistent with what one would generally expect from a complex system near criticality in physical systems, showing the long lasting effects of crashes on stock markets.

Emerging interdependence between stock values during financial crashes

PubMed Central

Tsui, Enoch Yan Lok; Saad, David

2017-01-01

To identify emerging interdependencies between traded stocks we investigate the behavior of the stocks of FTSE 100 companies in the period 2000-2015, by looking at daily stock values. Exploiting the power of information theoretical measures to extract direct influences between multiple time series, we compute the information flow across stock values to identify several different regimes. While small information flows is detected in most of the period, a dramatically different situation occurs in the proximity of global financial crises, where stock values exhibit strong and substantial interdependence for a prolonged period. This behavior is consistent with what one would generally expect from a complex system near criticality in physical systems, showing the long lasting effects of crashes on stock markets. PMID:28542278

Flow characteristics at U.S. Geological Survey streamgages in the conterminous United States

USGS Publications Warehouse

Wolock, David

2003-01-01

This dataset represents point locations and flow characteristics for current (as of November 20, 2001) and historical U.S. Geological Survey (USGS) streamgages in the conterminous United States. The flow characteristics were computed from the daily streamflow data recorded at each streamgage for the period of record. The attributes associated with each streamgage include: Station number Station name Station latitude (decimal degrees in North American Datum of 1983, NAD 83) Station longitude (decimal degrees in NAD 83) First date (year, month, day) of streamflow data Last date (year, month, day) of streamflow data Number of days of streamflow data Minimum and maximum daily flow for the period of record (cubic feet per second) Percentiles (1, 5, 10, 20, 25, 50, 75, 80, 90, 95, 99) of daily flow for the period of record (cubic feet per second) Average and standard deviation of daily flow for the period of record (cubic feet per second) Mean annual base-flow index (BFI: see supplemental information) computed for the period of record (fraction, ranging from 0 to 1) Year-to-year standard deviation of the annual base-flow index computed for the period of record (fraction) Number of years of data used to compute the base-flow index (years) Reported drainage area (square miles) Reported contributing drainage area (square miles) National Water Information System (NWIS)-Web page URL for streamgage Hydrologic Unit Code (HUC, 8 digit) Hydrologic landscape region (HLR) River Reach File 1 (RF1) segment identification number (E2RF1##) Station numbers, names, locations, and drainage areas were acquired through the National Water Information System (NWIS)-Web (http://water.usgs.gov/nwis) on November 20, 2001. The streamflow data used to compute flow characteristics were copied from the Water server (water.usgs.gov:/www/htdocs/nwisweb/data1/discharge/) on November 2, 2001. The missing value indicator for all attributes is -99. Some streamflow characteristics are missing for: (1) streamgages measuring flow subject to tidal effects, which cause flow to reverse directions, (2) streamgages with site information but no streamflow data at the time the data were retrieved, and (3) streamgages with record length too short to compute the base-flow index.

Construction of estimated flow- and load-duration curves for Kentucky using the Water Availability Tool for Environmental Resources (WATER)

USGS Publications Warehouse

Unthank, Michael D.; Newson, Jeremy K.; Williamson, Tanja N.; Nelson, Hugh L.

2012-01-01

Flow- and load-duration curves were constructed from the model outputs of the U.S. Geological Survey's Water Availability Tool for Environmental Resources (WATER) application for streams in Kentucky. The WATER application was designed to access multiple geospatial datasets to generate more than 60 years of statistically based streamflow data for Kentucky. The WATER application enables a user to graphically select a site on a stream and generate an estimated hydrograph and flow-duration curve for the watershed upstream of that point. The flow-duration curves are constructed by calculating the exceedance probability of the modeled daily streamflows. User-defined water-quality criteria and (or) sampling results can be loaded into the WATER application to construct load-duration curves that are based on the modeled streamflow results. Estimates of flow and streamflow statistics were derived from TOPographically Based Hydrological MODEL (TOPMODEL) simulations in the WATER application. A modified TOPMODEL code, SDP-TOPMODEL (Sinkhole Drainage Process-TOPMODEL) was used to simulate daily mean discharges over the period of record for 5 karst and 5 non-karst watersheds in Kentucky in order to verify the calibrated model. A statistical evaluation of the model's verification simulations show that calibration criteria, established by previous WATER application reports, were met thus insuring the model's ability to provide acceptably accurate estimates of discharge at gaged and ungaged sites throughout Kentucky. Flow-duration curves are constructed in the WATER application by calculating the exceedence probability of the modeled daily flow values. The flow-duration intervals are expressed as a percentage, with zero corresponding to the highest stream discharge in the streamflow record. Load-duration curves are constructed by applying the loading equation (Load = Flow*Water-quality criterion) at each flow interval.

Multi-site Stochastic Simulation of Daily Streamflow with Markov Chain and KNN Algorithm

NASA Astrophysics Data System (ADS)

Mathai, J.; Mujumdar, P.

2017-12-01

A key focus of this study is to develop a method which is physically consistent with the hydrologic processes that can capture short-term characteristics of daily hydrograph as well as the correlation of streamflow in temporal and spatial domains. In complex water resource systems, flow fluctuations at small time intervals require that discretisation be done at small time scales such as daily scales. Also, simultaneous generation of synthetic flows at different sites in the same basin are required. We propose a method to equip water managers with a streamflow generator within a stochastic streamflow simulation framework. The motivation for the proposed method is to generate sequences that extend beyond the variability represented in the historical record of streamflow time series. The method has two steps: In step 1, daily flow is generated independently at each station by a two-state Markov chain, with rising limb increments randomly sampled from a Gamma distribution and the falling limb modelled as exponential recession and in step 2, the streamflow generated in step 1 is input to a nonparametric K-nearest neighbor (KNN) time series bootstrap resampler. The KNN model, being data driven, does not require assumptions on the dependence structure of the time series. A major limitation of KNN based streamflow generators is that they do not produce new values, but merely reshuffle the historical data to generate realistic streamflow sequences. However, daily flow generated using the Markov chain approach is capable of generating a rich variety of streamflow sequences. Furthermore, the rising and falling limbs of daily hydrograph represent different physical processes, and hence they need to be modelled individually. Thus, our method combines the strengths of the two approaches. We show the utility of the method and improvement over the traditional KNN by simulating daily streamflow sequences at 7 locations in the Godavari River basin in India.

Bayesian forecasting and uncertainty quantifying of stream flows using Metropolis–Hastings Markov Chain Monte Carlo algorithm

DOE PAGES

Wang, Hongrui; Wang, Cheng; Wang, Ying; ...

2017-04-05

This paper presents a Bayesian approach using Metropolis-Hastings Markov Chain Monte Carlo algorithm and applies this method for daily river flow rate forecast and uncertainty quantification for Zhujiachuan River using data collected from Qiaotoubao Gage Station and other 13 gage stations in Zhujiachuan watershed in China. The proposed method is also compared with the conventional maximum likelihood estimation (MLE) for parameter estimation and quantification of associated uncertainties. While the Bayesian method performs similarly in estimating the mean value of daily flow rate, it performs over the conventional MLE method on uncertainty quantification, providing relatively narrower reliable interval than the MLEmore » confidence interval and thus more precise estimation by using the related information from regional gage stations. As a result, the Bayesian MCMC method might be more favorable in the uncertainty analysis and risk management.« less

The Massachusetts Sustainable-Yield Estimator: A decision-support tool to assess water availability at ungaged stream locations in Massachusetts

USGS Publications Warehouse

Archfield, Stacey A.; Vogel, Richard M.; Steeves, Peter A.; Brandt, Sara L.; Weiskel, Peter K.; Garabedian, Stephen P.

2010-01-01

Federal, State and local water-resource managers require a variety of data and modeling tools to better understand water resources. The U.S. Geological Survey, in cooperation with the Massachusetts Department of Environmental Protection, has developed a statewide, interactive decision-support tool to meet this need. The decision-support tool, referred to as the Massachusetts Sustainable-Yield Estimator (MA SYE) provides screening-level estimates of the sustainable yield of a basin, defined as the difference between the unregulated streamflow and some user-specified quantity of water that must remain in the stream to support such functions as recreational activities or aquatic habitat. The MA SYE tool was designed, in part, because the quantity of surface water available in a basin is a time-varying quantity subject to competing demands for water. To compute sustainable yield, the MA SYE tool estimates a daily time series of unregulated, daily mean streamflow for a 44-year period of record spanning October 1, 1960, through September 30, 2004. Selected streamflow quantiles from an unregulated, daily flow-duration curve are estimated by solving six regression equations that are a function of physical and climate basin characteristics at an ungaged site on a stream of interest. Streamflow is then interpolated between the estimated quantiles to obtain a continuous daily flow-duration curve. A time series of unregulated daily streamflow subsequently is created by transferring the timing of the daily streamflow at a reference streamgage to the ungaged site by equating exceedence probabilities of contemporaneous flow at the two locations. One of 66 reference streamgages is selected by kriging, a geostatistical method, which is used to map the spatial relation among correlations between the time series of the logarithm of daily streamflows at each reference streamgage and the ungaged site. Estimated unregulated, daily mean streamflows show good agreement with observed unregulated, daily mean streamflow at 18 streamgages located across southern New England. Nash-Sutcliffe efficiency goodness-of-fit values are between 0.69 and 0.98, and percent root-mean-square-error values are between 19 and 283 percent. The MA SYE tool provides an estimate of streamflow adjusted for current (2000-04) water withdrawals and discharges using a spatially referenced database of permitted groundwater and surface-water withdrawal and discharge volumes. For a user-selected basin, the database is queried to obtain the locations of water withdrawal or discharge volumes within the basin. Groundwater and surface-water withdrawals and discharges are subtracted and added, respectively, from the unregulated, daily streamflow at an ungaged site to obtain a streamflow time series that includes the effects of these withdrawals and discharges. Users also have the option of applying an analytical solution to the time-varying, groundwater withdrawal and discharge volumes that take into account the effects of the aquifer properties on the timing and magnitude of streamflow alteration. For the MA SYE tool, it is assumed that groundwater and surface-water divides are coincident. For areas of southeastern Massachusetts and Cape Cod where this assumption is known to be violated, groundwater-flow models are used to estimate average monthly streamflows at fixed locations. There are several limitations to the quality and quantity of the spatially referenced database of groundwater and surface-water withdrawals and discharges. The adjusted streamflow values do not account for the effects on streamflow of climate change, septic-system discharge, impervious area, non-public water-supply withdrawals less than 100,000 gallons per day, and impounded surface-water bodies.

Gazetteer of hydrologic characteristics of streams in Massachusetts; Housatonic River basin

USGS Publications Warehouse

Wandle, S.W.; Lippert, R.G.

1984-01-01

The Housatonic River basin includes streams that drain 504 square miles in western Massachusetts and 30.5 square miles in eastern New York. Drainage areas, using the latest available 1:24,000 scale topographic maps, were computed for the first time for streams draining more than 3 square miles and were recomputed for data-collection sites. Streamflow characteristics for four gaged streams were calculated using a new data base with daily flow records through 1981. These characteristics include annual and monthly flow statistics, duration of daily flow values, and the annual 7-day mean low flow at the 2-year and 10-year recurrence intervals. Seven-day low-flow statistics are presented for 52 partial-record sites, and the procedures used to determine the hydrologic characteristics of the basin are summarized. Basin characteristics representing 14 commonly used indices to estimate various streamflows are provided for selected gaging stations. This gazetteer will aid in the planning and siting of water-resources related activities and will provide a common data base for governmental agencies and the engineering and planning communities. (USGS)

Using repeat lidar to estimate sediment transport in a steep stream

NASA Astrophysics Data System (ADS)

Anderson, Scott; Pitlick, John

2014-03-01

Sediment fluxes in steep mountain streams remain difficult to quantify, despite their importance in geomorphology, ecology, and hazard analysis. In this work, aerial lidar surveys, acquired in 2002, 2008, and 2012, are used to quantify such fluxes in Tahoma Creek, a proglacial stream on Mount Rainier, Washington. As these surveys encompass all coarse sediment sources in the basin, we are able to translate geomorphic change into total bed material transport volumes for the time steps between surveys. By assuming that the relationship between daily sediment transport and daily mean discharge is of the form Qs=a(Q-Qc)b, our two observed total loads and estimates of daily mean discharge allow us to numerically solve for values of a and b to create a bed material sediment rating curve. Comparisons of our transport estimates with sediment deposition in a downstream reservoir indicate that our transport estimates and derived rating curve are reasonable. The method we present thus represents a plausible means of estimating transport rates in energetic settings or during extreme events, applicable whenever at least two cumulative sediment loads and the driving hydrology are known. We use these results to assess the performance of several bed load transport equations. The equations generally overpredict transport at low to moderate flows but significantly underpredict transport rates during an extreme event. Using a critical shear stress value appropriate for steep streams improves agreement at lower flows, whereas a shear-partitioning technique accounting for form drag losses significantly underpredicts transport at all flows.

The survey of ecologically acceptable flows in Slovenia

NASA Astrophysics Data System (ADS)

Smolar-Žvanut, Nataša; Burja, Darko

2008-11-01

Excessive water abstractions from watercourses constitute a negative impact on the structure and functioning of aquatic and riparian ecosystems. In order to preserve and improve the aquatic ecosystems it is therefore necessary to maintain adequate quantity and quality of water in watercourses, which can be ensured by providing ecologically acceptable flow (EAF). In Slovenia, a large diversity of watercourses regarding their hydrologic, morphological and ecological characteristics dictates the determination of EAF separately for individual sections of watercourses. Since 1994, the determination of EAF in Slovenia has been carried out primarily for the existing water abstractions such as hydroelectric power plants, fish farms, and to a lesser extent for the abstractions for drinking water, process water, recreation facilities and at the outflows from reservoirs. The results of EAF value analyses showed that the EAF values for individual water abstractions differed widely both with respect to the values of the mean annual minimum flow and the values of the mean daily flow. The results of analyses support the basis for the determination of EAF used in most EU countries, namely that EAF must be determined through interdisciplinary approach where the hydrologic data represent the benchmark values for the determination of EAF.

Can Low Frequency Measurements Be Good Enough? - A Statistical Assessment of Citizen Hydrology Streamflow Observations

NASA Astrophysics Data System (ADS)

Davids, J. C.; Rutten, M.; Van De Giesen, N.

2016-12-01

Hydrologic data has traditionally been collected with permanent installations of sophisticated and relatively accurate but expensive monitoring equipment at limited numbers of sites. Consequently, the spatial coverage of the data is limited and costs are high. Achieving adequate maintenance of sophisticated monitoring equipment often exceeds local technical and resource capacity, and permanently deployed monitoring equipment is susceptible to vandalism, theft, and other hazards. Rather than using expensive, vulnerable installations at a few points, SmartPhones4Water (S4W), a form of Citizen Hydrology, leverages widely available mobile technology to gather hydrologic data at many sites in a manner that is repeatable and scalable. However, there is currently a limited understanding of the impact of decreased observational frequency on the accuracy of key streamflow statistics like minimum flow, maximum flow, and runoff. As a first step towards evaluating the tradeoffs between traditional continuous monitoring approaches and emerging Citizen Hydrology methods, we randomly selected 50 active U.S. Geological Survey (USGS) streamflow gauges in California. We used historical 15 minute flow data from 01/01/2008 through 12/31/2014 to develop minimum flow, maximum flow, and runoff values (7 year total) for each gauge. In order to mimic lower frequency Citizen Hydrology observations, we developed a bootstrap randomized subsampling with replacement procedure. We calculated the same statistics, along with their respective distributions, from 50 subsample iterations with four different subsampling intervals (i.e. daily, three day, weekly, and monthly). Based on our results we conclude that, depending on the types of questions being asked, and the watershed characteristics, Citizen Hydrology streamflow measurements can provide useful and accurate information. Depending on watershed characteristics, minimum flows were reasonably estimated with subsample intervals ranging from daily to monthly. However, maximum flows in most cases were poorly characterized, even at daily subsample intervals. In general, runoff volumes were accurately estimated from daily, three day, weekly, and even in some cases, monthly observations.

Estimation of daily mean streamflow for ungaged stream locations in the Delaware River Basin, water years 1960–2010

USGS Publications Warehouse

Stuckey, Marla H.

2016-06-09

The ability to characterize baseline streamflow conditions, compare them with current conditions, and assess effects of human activities on streamflow is fundamental to water-management programs addressing water allocation, human-health issues, recreation needs, and establishment of ecological flow criteria. The U.S. Geological Survey, through the National Water Census, has developed the Delaware River Basin Streamflow Estimator Tool (DRB-SET) to estimate baseline (minimally altered) and altered (affected by regulation, diversion, mining, or other anthropogenic activities) and altered streamflow at a daily time step for ungaged stream locations in the Delaware River Basin for water years 1960–2010. Daily mean baseline streamflow is estimated by using the QPPQ method to equate streamflow expressed as a percentile from the flow-duration curve (FDC) for a particular day at an ungaged stream location with the percentile from a FDC for the same day at a hydrologically similar gaged location where streamflow is measured. Parameter-based regression equations were developed for 22 exceedance probabilities from the FDC for ungaged stream locations in the Delaware River Basin. Water use data from 2010 is used to adjust the baseline daily mean streamflow generated from the QPPQ method at ungaged stream locations in the Delaware River Basin to reflect current, or altered, conditions. To evaluate the effectiveness of the overall QPPQ method contained within DRB-SET, a comparison of observed and estimated daily mean streamflows was performed for 109 reference streamgages in and near the Delaware River Basin. The Nash-Sutcliffe efficiency (NSE) values were computed as a measure of goodness of fit. The NSE values (using log10 streamflow values) ranged from 0.22 to 0.98 (median of 0.90) for 45 streamgages in the Upper Delaware River Basin and from -0.37 to 0.98 (median of 0.79) for 41 streamgages in the Lower Delaware River Basin.

Evaporation, precipitation, and associated salinity changes at a humid, subtropical estuary

USGS Publications Warehouse

Sumner, D.M.; Belaineh, G.

2005-01-01

The distilling effect of evaporation and the diluting effect of precipitation on salinity at two estuarine sites in the humid subtropical setting of the Indian River Lagoon, Florida, were evaluated based on daily evaporation computed with an energy-budget method and measured precipitation. Despite the larger magnitude of evaporation (about 1,580 mm yr-1) compared to precipitation (about 1,180 mm yr-1) between February 2002 and January 2004, the variability of monthly precipitation induced salinity changes was more than twice the variability of evaporation induced changes. Use of a constant, mean value of evaporation, along with measured values of daily precipitation, were sufficient to produce simulated salinity changes that contained little monthly (root-mean-square error = 0.33??? mo-1 and 0.52??? mo-1 at the two sites) or cumulative error (<1??? yr-1) compared to simulations that used computed daily values of evaporation. This result indicates that measuring the temporal variability in evaporation may not be critical to simulation of salinity within the lagoon. Comparison of evaporation and precipitation induced salinity changes with measured salinity changes indicates that evaporation and precipitation explained only 4% of the changes in salinity within a flow-through area of the lagoon; surface water and ocean inflows probably accounted for most of the variability in salinity at this site. Evaporation and precipitation induced salinity changes explained 61% of the variability in salinity at a flow-restricted part of the lagoon. ?? 2005 Estuarine Research Federation.

Hydrologic data collection activities in the Solomon Gulch basin near Valdez, Alaska

USGS Publications Warehouse

Bigelow, B.B.

1988-01-01

In 1981, the Alaska Power Authority completed construction of a dam spillway at the north end of Solomon Lake near Valdez. Regulation and diversion from the dam since 1982 have significantly altered the natural flow characteristics of Solomon Gulch. In September 1986, the Geological Survey began data collection to determine mean daily discharge at four sites below Solomon Lake and thus document the effects of regulation and diversion of water on the flow at various points in the system. Periodic discharge measurements and continuous records of water stage were obtained at two of the sites, and daily discharge values were computed for all four sites. The report contains descriptions of the data collection sites and the discharge records for each site for September 1986 and water year 1987. (USGS)

Use of instantaneous streamflow measurements to improve regression estimates of index flow for the summer month of lowest streamflow in Michigan

USGS Publications Warehouse

Holtschlag, David J.

2011-01-01

In Michigan, index flow Q50 is a streamflow characteristic defined as the minimum of median flows for July, August, and September. The state of Michigan uses index flow estimates to help regulate large (greater than 100,000 gallons per day) water withdrawals to prevent adverse effects on characteristic fish populations. At sites where long-term streamgages are located, index flows are computed directly from continuous streamflow records as GageQ50. In an earlier study, a multiple-regression equation was developed to estimate index flows IndxQ50 at ungaged sites. The index equation explains about 94 percent of the variability of index flows at 147 (index) streamgages by use of six explanatory variables describing soil type, aquifer transmissivity, land cover, and precipitation characteristics. This report extends the results of the previous study, by use of Monte Carlo simulations, to evaluate alternative flow estimators, DiscQ50, IntgQ50, SiteQ50, and AugmQ50. The Monte Carlo simulations treated each of the available index streamgages, in turn, as a miscellaneous site where streamflow conditions are described by one or more instantaneous measurements of flow. In the simulations, instantaneous flows were approximated by daily mean flows at the corresponding site. All estimators use information that can be obtained from instantaneous flow measurements and contemporaneous daily mean flow data from nearby long-term streamgages. The efficacy of these estimators was evaluated over a set of measurement intensities in which the number of simulated instantaneous flow measurements ranged from 1 to 100 at a site. The discrete measurement estimator DiscQ50 is based on a simple linear regression developed between information on daily mean flows at five or more streamgages near the miscellaneous site and their corresponding GageQ50 index flows. The regression relation then was used to compute a DiscQ50 estimate at the miscellaneous site by use of the simulated instantaneous flow measurement. This process was repeated to develop a set of DiscQ50 estimates for all simulated instantaneous measurements, a weighted DiscQ50 estimate was formed from this set. Results indicated that the expected value of this weighted estimate was more precise than the IndxQ50 estimate for all measurement intensities evaluated. The integrated index-flow estimator, IntgQ50, was formed by computing a weighted average of the index estimate IndxQ50 and the DiscQ50 estimate. Results indicated that the IntgQ50 estimator was more precise than the DiscQ50 estimator at low measurement intensities of one to two measurements. At greater measurement intensities, the precision of the IntgQ50 estimator converges to the DiscQ50 estimator. Neither the DiscQ50 nor the IntgQ50 estimators provided site-specific estimates. In particular, although expected values of DiscQ50 and IntgQ50 estimates converge with increasing measurement intensity, they do not necessarily converge to the site-specific value of Q50. The site estimator of flow, SiteQ50, was developed to facilitate this convergence at higher measurement intensities. This is accomplished by use of the median of simulated instantaneous flow values for each measurement intensity level. A weighted estimate of the median and information associated with the IntgQ50 estimate was used to form the SiteQ50 estimate. Initial simulations indicate that the SiteQ50 estimator generally has greater precision than the IntgQ50 estimator at measurement intensities greater than 3, however, additional analysis is needed to identify streamflow conditions under which instantaneous measurements will produce estimates that generally converge to the index flows. A preliminary augmented index regression equation was developed, which contains the index regression estimate and two additional variables associated with base-flow recession characteristics. When these recession variables were estimated as the medians of recession parameters compute

Follicle vascularity coordinates corpus luteum blood flow and progesterone production.

PubMed

de Tarso, S G S; Gastal, G D A; Bashir, S T; Gastal, M O; Apgar, G A; Gastal, E L

2017-03-01

Colour Doppler ultrasonography was used to compare the ability of preovulatory follicle (POF) blood flow and its dimensions to predict the size, blood flow and progesterone production capability of the subsequent corpus luteum (CL). Cows (n=30) were submitted to a synchronisation protocol. Follicles ≥7mm were measured and follicular wall blood flow evaluated every 12h for approximately 3.5 days until ovulation. After ovulation, cows were scanned daily for 8 days and similar parameters were evaluated for the CL. Blood samples were collected and plasma progesterone concentrations quantified. All parameters were positively correlated. Correlation values ranged from 0.26 to 0.74 on data normalised to ovulation and from 0.31 to 0.74 on data normalised to maximum values. Correlations between calculated ratios of both POF and CL in data normalised to ovulation and to maximum values ranged from moderate (0.57) to strong (0.87). Significant (P<0.0001) linear regression analyses were seen in all comparisons. In conclusion, higher correlations were observed between the dimensions of POF and/or CL and blood flow of both structures, as well as POF and/or CL blood flow with plasma progesterone concentrations of the resultant CL. These findings indicate that follicle vascularity coordinates CL blood flow and progesterone production in synchronised beef cows.

Streamflow record extension for selected streams in the Susitna River Basin, Alaska

USGS Publications Warehouse

Curran, Janet H.

2012-01-01

Daily streamflow records for water years 1950–2010 in the Susitna River Basin range in length from 4 to 57 years, and many are distributed within that period in a way that might not adequately represent long-term streamflow conditions. Streamflow in the basin is affected by the Pacific Decadal Oscillation (PDO), a multi-decadal climate pattern that shifted from a cool phase to a warm phase in 1976. Records for many streamgages in the basin fell mostly within one phase of the PDO, such that monthly and annual statistics from observed records might not reflect streamflow conditions over a longer period. Correlations between daily discharge values sufficed for extending streamflow records at 11 of the 14 streamgages in the basin on the basis of relatively long-term records for one or more of the streamgages within the basin, or one outside the basin, that were defined as index stations. Streamflow at the index stations was hydrologically responsive to glacier melt and snowmelt, and correlated well with flow from similar high-elevation, glaciated basins, but flow in low-elevation basins without glaciers could not be correlated to flow at any of the index stations. Kendall-Theil Robust Line multi-segment regression equations developed for one or more index stations were used to extend daily discharge values to the full 61-year period for all 11 streamgages. Monthly and annual statistics prepared for the extended records show shifts in timing of breakup and freeze-up and magnitude of snowmelt peaks largely predicted by the PDO phase.

Hydrologic data from urban watersheds in the Tampa Bay area, Florida

USGS Publications Warehouse

Lopez, Miguel A.; Michaelis, D.M.

1979-01-01

Hydrologic data are being collected in 10 urbanized watersheds located in the Tampa Bay area, Florida. The gaged watersheds have impervious areas that range from 19 percent for a residential watershed in north Tampa to nearly 100 percent for a downtown Tampa watershed. Land-use types, including roads, residential, commercial, industrial, institutional, recreational , and open space, have been determined for each watershed. Rainfall and storm runoff data collected since 1971 for one site and since 1975 for six other sites through September 1976, have been processed. These data are recorded at 5-minute intervals and are stored in the U. S. Geological Survey WATSTORE unit values file. Daily rainfall at 12 sites and daily pan evaporation at one site have been stored in the WATSTORE daily values file. Chemical and biological analyses of storm runoff for six sites, base flow for seven sites, and analyses of bottom material for seven sites are also stored in the WATSTORE water-quality files. Rainfall and storm runoff for selected storms, daily rainfall, and daily pan-evaporation data are summarized in this report. Water-quality analyses of all water-quality samples also are listed. (Woodard-USGS).

Simulation of daily streamflow for nine river basins in eastern Iowa using the Precipitation-Runoff Modeling System

USGS Publications Warehouse

Haj, Adel E.; Christiansen, Daniel E.; Hutchinson, Kasey J.

2015-10-14

The accuracy of Precipitation-Runoff Modeling System model streamflow estimates of nine river basins in eastern Iowa as compared to measured values at U.S. Geological Survey streamflow-gaging stations varied. The Precipitation-Runoff Modeling System models of nine river basins in eastern Iowa were satisfactory at estimating daily streamflow at 57 of the 79 calibration sites and 13 of the 14 validation sites based on statistical results. Unsatisfactory performance can be contributed to several factors: (1) low flow, no flow, and flashy flow conditions in headwater subbasins having a small drainage area; (2) poor representation of the groundwater and storage components of flow within a basin; (3) lack of accounting for basin withdrawals and water use; and (4) the availability and accuracy of meteorological input data. The Precipitation- Runoff Modeling System models of nine river basins in eastern Iowa will provide water-resource managers with a consistent and documented method for estimating streamflow at ungaged sites and aid in environmental studies, hydraulic design, water management, and water-quality projects.

Loan and nonloan flows in the Australian interbank network

NASA Astrophysics Data System (ADS)

Sokolov, Andrey; Webster, Rachel; Melatos, Andrew; Kieu, Tien

2012-05-01

High-value transactions between banks in Australia are settled in the Reserve Bank Information and Transfer System (RITS) administered by the Reserve Bank of Australia. RITS operates on a real-time gross settlement (RTGS) basis and settles payments and transfers sourced from the SWIFT payment delivery system, the Austraclear securities settlement system, and the interbank transactions entered directly into RITS. In this paper, we analyse a dataset received from the Reserve Bank of Australia that includes all interbank transactions settled in RITS on an RTGS basis during five consecutive weekdays from 19 February 2007 inclusive, a week of relatively quiescent market conditions. The source, destination, and value of each transaction are known, which allows us to separate overnight loans from other transactions (nonloans) and reconstruct monetary flows between banks for every day in our sample. We conduct a novel analysis of the flow stability and examine the connection between loan and nonloan flows. Our aim is to understand the underlying causal mechanism connecting loan and nonloan flows. We find that the imbalances in the banks' exchange settlement funds resulting from the daily flows of nonloan transactions are almost exactly counterbalanced by the flows of overnight loans. The correlation coefficient between loan and nonloan imbalances is about -0.9 on most days. Some flows that persist over two consecutive days can be highly variable, but overall the flows are moderately stable in value. The nonloan network is characterised by a large fraction of persistent flows, whereas only half of the flows persist over any two consecutive days in the loan network. Moreover, we observe an unusual degree of coherence between persistent loan flow values on Tuesday and Wednesday. We probe static topological properties of the Australian interbank network and find them consistent with those observed in other countries.

Low-flow frequency and flow duration of selected South Carolina streams in the Catawba-Wateree and Santee River Basins through March 2012

USGS Publications Warehouse

Feaster, Toby D.; Guimaraes, Wladmir B.

2014-01-01

Part of the mission of both the South Carolina Department of Health and Environmental Control and the South Carolina Department of Natural Resources is to protect and preserve South Carolina’s water resources. Doing so requires an ongoing understanding of streamflow characteristics of the rivers and streams in South Carolina. A particular need is information concerning the low-flow characteristics of streams, which is especially important for effectively managing the State’s water resources during critical flow periods, such as during the historic droughts that South Carolina has experienced in the past few decades. In 2008, the U.S. Geological Survey, in cooperation with the South Carolina Department of Health and Environmental Control, initiated a study to update low-flow statistics at continuous-record streamgaging stations operated by the U.S. Geological Survey in South Carolina. This report presents the low-flow statistics for 11 selected streamgaging stations in the Catawba-Wateree and Santee River Basins in South Carolina and 2 in North Carolina. For five of the streamgaging stations, low-flow statistics include daily mean flow durations or the 5-, 10-, 25-, 50-, 75-, 90-, and 95-percent probability of exceedance and the annual minimum 1-, 3-, 7-, 14-, 30-, 60-, and 90-day mean flows with recurrence intervals of 2, 5, 10, 20, 30, and 50 years, depending on the length of record available at the streamgaging station. For the other eight streamgaging stations, only daily mean flow durations and (or) exceedance percentiles of annual minimum 7-day average flows are provided due to regulation. In either case, the low-flow statistics were computed from records available through March 31, 2012. Of the five streamgaging stations for which recurrence interval computations were made, three streamgaging stations in South Carolina were compared to low-flow statistics that were published in previous U.S. Geological Survey reports. A comparison of the low-flow statistics for the annual minimum 7-day average streamflow with a 10-year recurrence interval (7Q10) from this study with the most recently published values indicated that two of the streamgaging stations had values lower than the previous values and the 7Q10 for the third station remained unchanged at zero. Low-flow statistics are influenced by length of record, hydrologic regime under which the data were collected, analytical techniques used, and other factors, such as urbanization, diversions, and droughts that may have occurred in the basin.

The effect of flow data resolution on sediment yield estimation and channel design

NASA Astrophysics Data System (ADS)

Rosburg, Tyler T.; Nelson, Peter A.; Sholtes, Joel S.; Bledsoe, Brian P.

2016-07-01

The decision to use either daily-averaged or sub-daily streamflow records has the potential to impact the calculation of sediment transport metrics and stream channel design. Using bedload and suspended load sediment transport measurements collected at 138 sites across the United States, we calculated the effective discharge, sediment yield, and half-load discharge using sediment rating curves over long time periods (median record length = 24 years) with both daily-averaged and sub-daily streamflow records. A comparison of sediment transport metrics calculated with both daily-average and sub-daily stream flow data at each site showed that daily-averaged flow data do not adequately represent the magnitude of high stream flows at hydrologically flashy sites. Daily-average stream flow data cause an underestimation of sediment transport and sediment yield (including the half-load discharge) at flashy sites. The degree of underestimation was correlated with the level of flashiness and the exponent of the sediment rating curve. No consistent relationship between the use of either daily-average or sub-daily streamflow data and the resultant effective discharge was found. When used in channel design, computed sediment transport metrics may have errors due to flow data resolution, which can propagate into design slope calculations which, if implemented, could lead to unwanted aggradation or degradation in the design channel. This analysis illustrates the importance of using sub-daily flow data in the calculation of sediment yield in urbanizing or otherwise flashy watersheds. Furthermore, this analysis provides practical charts for estimating and correcting these types of underestimation errors commonly incurred in sediment yield calculations.

18 CFR 157.14 - Exhibits.

Code of Federal Regulations, 2013 CFR

2013-04-01

...) Exhibit G—Flow diagrams showing daily design capacity and reflecting operation with and without proposed facilities added. A flow diagram showing daily design capacity and reflecting operating conditions with only existing facilities in operation. A second flow diagram showing daily design capacity and reflecting...

18 CFR 157.14 - Exhibits.

Code of Federal Regulations, 2012 CFR

2012-04-01

...) Exhibit G—Flow diagrams showing daily design capacity and reflecting operation with and without proposed facilities added. A flow diagram showing daily design capacity and reflecting operating conditions with only existing facilities in operation. A second flow diagram showing daily design capacity and reflecting...

18 CFR 157.14 - Exhibits.

Code of Federal Regulations, 2010 CFR

2010-04-01

...) Exhibit G—Flow diagrams showing daily design capacity and reflecting operation with and without proposed facilities added. A flow diagram showing daily design capacity and reflecting operating conditions with only existing facilities in operation. A second flow diagram showing daily design capacity and reflecting...

18 CFR 157.14 - Exhibits.

Code of Federal Regulations, 2011 CFR

2011-04-01

...) Exhibit G—Flow diagrams showing daily design capacity and reflecting operation with and without proposed facilities added. A flow diagram showing daily design capacity and reflecting operating conditions with only existing facilities in operation. A second flow diagram showing daily design capacity and reflecting...

18 CFR 157.14 - Exhibits.

Code of Federal Regulations, 2014 CFR

2014-04-01

...) Exhibit G—Flow diagrams showing daily design capacity and reflecting operation with and without proposed facilities added. A flow diagram showing daily design capacity and reflecting operating conditions with only existing facilities in operation. A second flow diagram showing daily design capacity and reflecting...

Accuracy of mini peak flow meters in indicating changes in lung function in children with asthma.

PubMed Central

Sly, P. D.; Cahill, P.; Willet, K.; Burton, P.

1994-01-01

OBJECTIVE--To assess whether mini flow meters used to measure peak expiratory flow can track changes in lung function and indicate clinically important changes. DESIGN--Comparison of measurements with a spirometer and different brands of mini flow meter; the meters were allocated to subjects haphazardly. SUBJECTS--12 boys with asthma aged 11 to 17 attending boarding school. MAIN OUTCOME MEASURES--Peak expiratory flow measured twice daily for three months with a spirometer and at least one of four brands of mini flow meter. RESULTS--The relation between changes in lung function measured with the spirometer and those measured with the mini flow meters was generally poor. In all, 26 episodes (range 1-3 in an individual child) of clinically important deterioration in lung function were detected from the records obtained with the spirometer. One mini flow meter detected six of 19 episodes, one detected six of 15, one detected six of 18, and one detected three of 21. CONCLUSIONS--Not only are the absolute values of peak expiratory flow obtained with mini flow meters inaccurate but the clinical message may also be incorrect. These findings do not imply that home monitoring of peak expiratory flow has no place in the management of childhood asthma but that the values obtained should be interpreted cautiously. PMID:8148680

Evapotranspiration from forage grass replacing native vegetation in the Gila River valley of Arizona

USGS Publications Warehouse

Leppanen, O.E.

1981-01-01

Estimates of evapotranspiration from an area of forage grass, which had been planted to replace native vegetation of little economic value, were made daily for a 363-day period in 1969 and 1970. The measurement site was located in the Gila River valley in east-central Arizona. The forage, panigrass (Panicum antidotale Retz.), grew from seed during the early summer of 1969 and after winterkill, regrew in 1970. Daily evapotranspiration estimates, which were based on energy budget measurements, ranged from a maximum of 9.2 millimeters to small amounts of condensation. Two daily values of substantial condensation (0.9 and 0.4 millimeter) were of dubious quality, but were retained in the record. The annual evapotranspiration was 989 millimeters, of which about 332 millimeters came from precipitation at the site. The water table fluctuated between 210 and 280 centimeters below land surface. However, the measurement site was near a wash, so that undocumented, shallower subterranean flows may have occurred. (USGS)

Flow velocity, water temperature, and conductivity in Shark River Slough, Everglades National Park, Florida: June 2002-July 2003

USGS Publications Warehouse

Riscassi, Ami L.; Schaffranek, Raymond W.

2004-01-01

The data described in this report were collected in the U. S. Geological Survey (USGS) Priority Ecosystems Science project investigating Forcing Effects on Flow Structure in Vegetated Wetlands of the Everglades. Data collected at five locations in Shark River Slough, Everglades National Park, during the 2002-2003 wet season are documented in the report. Methods used to process the data are described. Daily mean flow velocities, water temperatures, and specific conductance values are presented in the appendices. The quality-checked and edited data have been compiled and stored on the USGS South Florida Information Access (SOFIA) website http://sofia.usgs.gov.

Low-flow frequency and flow duration of selected South Carolina streams in the Savannah and Salkehatchie River Basins through March 2014

USGS Publications Warehouse

Feaster, Toby D.; Guimaraes, Wladmir B.

2016-07-14

An ongoing understanding of streamflow characteristics of the rivers and streams in South Carolina is important for the protection and preservation of the State’s water resources. Information concerning the low-flow characteristics of streams is especially important during critical flow periods, such as during the historic droughts that South Carolina has experienced in the past few decades.In 2008, the U.S. Geological Survey, in cooperation with the South Carolina Department of Health and Environmental Control, initiated a study to update low-flow statistics at continuous-record streamgaging stations operated by the U.S. Geological Survey in South Carolina. This report presents the low-flow statistics for 28 selected streamgaging stations in the Savannah and Salkehatchie River Basins in South Carolina. The low-flow statistics include daily mean flow durations for the 5-, 10-, 25-, 50-, 75-, 90-, and 95-percent probability of exceedance and the annual minimum 1-, 3-, 7-, 14-, 30-, 60-, and 90-day mean flows with recurrence intervals of 2, 5, 10, 20, 30, and 50 years, depending on the length of record available at the streamgaging station. The low-flow statistics were computed from records available through March 31, 2014.Low-flow statistics are influenced by length of record, hydrologic regime under which the data were collected, analytical techniques used, and other factors, such as urbanization, diversions, and droughts that may have occurred in the basin. To assess changes in the low-flow statistics from the previously published values, a comparison of the low-flow statistics for the annual minimum 7-day average streamflow with a 10-year recurrence interval (7Q10) from this study was made with the most recently published values. Of the 28 streamgaging stations for which recurrence interval computations were made, 14 streamgaging stations were suitable for comparing to low-flow statistics that were previously published in U.S. Geological Survey reports. These comparisons indicated that seven of the streamgaging stations had values lower than the previous values, two streamgaging stations had values higher than the previous values, and two streamgaging stations had values that were unchanged from previous values. The remaining three stations for which previous 7Q10 values were computed, which are located on the main stem of the Savannah River, were not compared with current estimates because of differences in the way the pre-regulation and regulated flow data were analyzed.

The optimal dissolved oxygen profile in a nitrifying activated sludge process - comparisons with ammonium feedback control.

PubMed

Amand, L; Carlsson, B

2013-01-01

Ammonium feedback control is increasingly used to determine the dissolved oxygen (DO) set-point in aerated activated sludge processes for nitrogen removal. This study compares proportional-integral (PI) ammonium feedback control with a DO profile created from a mathematical minimisation of the daily air flow rate. All simulated scenarios are set to reach the same treatment level of ammonium, based on a daily average concentration. The influent includes daily variations only and the model has three aerated zones. Comparisons are made at different plant loads and DO concentrations, and the placement of the ammonium sensor is investigated. The results show that ammonium PI control can achieve the best performance if the DO set-point is limited at a maximum value and with little integral action in the controller. Compared with constant DO control the best-performing ammonium controller can achieve 1-3.5% savings in the air flow rate, while the optimal solution can achieve a 3-7% saving. Energy savings are larger when operating at higher DO concentrations.

Simulating Daily and Sub-daily Water Flow in Large, Semi-arid Watershed Using SWAT: A Case Study of Nueces River Basin, Texas

NASA Astrophysics Data System (ADS)

Bassam, S.; Ren, J.

2015-12-01

Runoff generated during heavy rainfall imposes quick, but often intense, changes in the flow of streams, which increase the chance of flash floods in the vicinity of the streams. Understanding the temporal response of streams to heavy rainfall requires a hydrological model that considers meteorological, hydrological, and geological components of the streams and their watersheds. SWAT is a physically-based, semi-distributed model that is capable of simulating water flow within watersheds with both long-term, i.e. annually and monthly, and short-term (daily and sub-daily) time scales. However, the capability of SWAT in sub-daily water flow modeling within large watersheds has not been studied much, compare to long-term and daily time scales. In this study we are investigating the water flow in a large, semi-arid watershed, Nueces River Basin (NRB) with the drainage area of 16950 mi2 located in South Texas, with daily and sub-daily time scales. The objectives of this study are: (1) simulating the response of streams to heavy, and often quick, rainfall, (2) evaluating SWAT performance in sub-daily modeling of water flow within a large watershed, and (3) examining means for model performance improvement during model calibration and verification based on results of sensitivity and uncertainty analysis. The results of this study can provide important information for water resources planning during flood seasons.

Decision Support System for Evaluation of Gunnison River Flow Regimes With Respect To Resources of the Black Canyon of the Gunnison National Park

USGS Publications Warehouse

Auble, Gregor T.; Wondzell, Mark; Talbert, Colin

2009-01-01

This report describes and documents a decision support system for the Gunnison River in Black Canyon of the Gunnison National Park. It is a macro-embedded EXCEL program that calculates and displays indicators representing valued characteristics or processes in the Black Canyon based on daily flows of the Gunnison River. The program is designed to easily accept input from downloaded stream gage records or output from the RIVERWARE reservoir operations model being used for the upstream Aspinall Unit. The decision support system is structured to compare as many as eight alternative flow regimes, where each alternative is represented by a daily sequence of at least 20 calendar years of streamflow. Indicators include selected flow statistics, riparian plant community distribution, clearing of box elder by inundation and scour, several measures of sediment mobilization, trout fry habitat, and federal reserved water rights. Calculation of variables representing National Park Service federal reserved water rights requires additional secondary input files pertaining to forecast and actual basin inflows and storage levels in Blue Mesa reservoir. Example input files representing a range of situations including historical, reconstructed natural, and simulated alternative reservoir operations are provided with the software.

Statistical summaries of streamflow data for selected gaging stations on and near the Idaho National Engineering Laboratory, Idaho, through September 1990

USGS Publications Warehouse

Stone, M.A.J.; Mann, Larry J.; Kjelstrom, L.C.

1993-01-01

Statistical summaries and graphs of streamflow data were prepared for 13 gaging stations with 5 or more years of continuous record on and near the Idaho National Engineering Laboratory. Statistical summaries of streamflow data for the Big and Little Lost Rivers and Birch Creek were analyzed as a requisite for a comprehensive evaluation of the potential for flooding of facilities at the Idaho National Engineering Laboratory. The type of statistical analyses performed depended on the length of streamflow record for a gaging station. Streamflow statistics generated for stations with 5 to 9 years of record were: (1) magnitudes of monthly and annual flows; (2) duration of daily mean flows; and (3) maximum, median, and minimum daily mean flows. Streamflow statistics generated for stations with 10 or more years of record were: (1) magnitudes of monthly and annual flows; (2) magnitudes and frequencies of daily low, high, instantaneous peak (flood frequency), and annual mean flows; (3) duration of daily mean flows; (4) exceedance probabilities of annual low, high, instantaneous peak, and mean annual flows; (5) maximum, median, and minimum daily mean flows; and (6) annual mean and mean annual flows.

40 CFR 63.1571 - How and when do I conduct a performance test or other initial compliance demonstration?

Code of Federal Regulations, 2010 CFR

2010-07-01

... heating value, TOC emission rate, and total organic HAP emission rate expected to yield the highest daily... conditions; (3) You may use maximum flow rate, TOC emission rate, organic HAP emission rate, or organic HAP or TOC concentration specified or implied within a permit limit applicable to the process vent; or (4...

Evaluation of a watershed model for estimating daily flow using limited flow measurements

USDA-ARS?s Scientific Manuscript database

The Soil and Water Assessment Tool (SWAT) model was evaluated for estimation of continuous daily flow based on limited flow measurements in the Upper Oyster Creek (UOC) watershed. SWAT was calibrated against limited measured flow data and then validated. The Nash-Sutcliffe model Efficiency (NSE) and...

Selected Streamflow Statistics for Streamgaging Stationsin Northeastern Maryland, 2006

USGS Publications Warehouse

Ries, Kernell G.

2006-01-01

Streamflow statistics were calculated for 47 U.S. Geological Survey (USGS) streamgaging stations in northeastern Maryland, in cooperation with (1) the University of Maryland, Baltimore County, Center for Urban Environmental Research and Education; (2) the Baltimore City Department of Public Works; and (3) the Baltimore County Department of Environmental Protection and Resource Management. The statistics include the mean, minimum, maximum, and standard deviation of the daily mean discharges for the periods of record at the stations, as well as flow-duration and low-flow frequency statistics. The flow-duration statistics include the 1-, 2-, 5-, 10-, 15-, 20-, 25-, 30-, 40-, 50-, 60-, 70-, 75-, 80-, 85-, 90-, 95-, 98-, and 99-percent duration discharges. The low-flow frequency statistics include the average discharges for 1, 7, 14, and 30 days that recur, on average, once in 1.01, 2, 5, 10, 20, 50, and 100 years. The statistics were computed only for the 25 stations with periods of record of 10 years or more. The statistics were computed from records available through September 30, 2004 using standard methods and computer software developed by the USGS. A comparison between low-flow frequency statistics computed for this study and for a previous study that used data available through September 30, 1989 was done for seven stations. The comparison indicated that, for the 7-day mean low flow, the newer values were 19.8 and 15.3 percent lower for the 20- and 10-year recurrence intervals, respectively, and 2.1 percent higher for the 2-year recurrence interval, than the older values. For the 14-day mean low flow, the newer 20- and 10-year values were 25.2 and 15.5 percent lower, respectively, and the 2-year value was 2.9 percent higher than the older values. For the 30-day mean low flow, the newer 20-, 10-, and 2-year values were 10.8, 7.9, and 0.8 percent lower, respectively, than the older values. The newer values are generally lower than the older ones most likely because two major droughts have occurred since the older study was completed.

Effects of daily precipitation and evapotranspiration patterns on flow and VOC transport to groundwater along a watershed flow path

USGS Publications Warehouse

Johnson, Richard L.; Thoms, R.B.; Zogorski, J.S.

2003-01-01

MTBE and other volatile organic compounds (VOCs) are widely observed in shallow groundwater in the United States, especially in urban areas. Previous studies suggest that the atmosphere and/or nonpoint surficial sources could be responsible for some of those VOCs, especially in areas where there is net recharge to groundwater. However, in semi-arid locations where annual potential evapotranspiration can exceed annual precipitation, VOC detections in groundwater can be frequent. VOC transport to groundwater under net discharge conditions has not previously been examined. A numerical model is used here to demonstrate that daily precipitation and evapotranspiration (ET) patterns can have a significant effect on recharge to groundwater, water table elevations, and VOC transport. Ten-year precipitation/ET scenarios from six sites in the United States are examined using both actual daily observed values and “average” pulsed precipitation. MTBE and tetrachloroethylene transport, including gas-phase diffusion, are considered. The effects of the precipitation/ET scenarios on net recharge and groundwater flow are significant and complicated, especially under low-precipitation conditions when pulsed precipitation can significantly underestimate transport to groundwater. In addition to precipitation and evapotranspiration effects, location of VOC entry into the subsurface within the watershed is important for transport in groundwater. This is caused by groundwater hydraulics at the watershed scale as well as variations in ET within the watershed. The model results indicate that it is important to consider both daily precipitation/ET patterns and location within the watershed in order to interpret VOC occurrence in groundwater, especially in low-precipitation settings.

Flow Velocity, Water Temperature, and Conductivity in Shark River Slough, Everglades National Park, Florida: August 2001-June 2002

USGS Publications Warehouse

Riscassi, Ami L.; Schaffranek, Raymond W.

2003-01-01

The data-collection effort described in this report is in support of the U.S. Geological Survey (USGS) Place-Based Studies project investigating 'Forcing Effects on Flow Structure in Vegetated Wetlands of the Everglades.' Data collected at four locations in Shark River Slough, Everglades National Park, during the 2001-2002 wet season are documented in the report and methods used to process the data are described. Daily mean flow velocities, water temperatures, and specific conductance values are presented in the appendices of the report. The quality-checked and edited data have been compiled and stored on the USGS South Florida Information Access (SOFIA) website http://sofia.usgs.gov.

Passenger Flow Forecasting Research for Airport Terminal Based on SARIMA Time Series Model

NASA Astrophysics Data System (ADS)

Li, Ziyu; Bi, Jun; Li, Zhiyin

2017-12-01

Based on the data of practical operating of Kunming Changshui International Airport during2016, this paper proposes Seasonal Autoregressive Integrated Moving Average (SARIMA) model to predict the passenger flow. This article not only considers the non-stationary and autocorrelation of the sequence, but also considers the daily periodicity of the sequence. The prediction results can accurately describe the change trend of airport passenger flow and provide scientific decision support for the optimal allocation of airport resources and optimization of departure process. The result shows that this model is applicable to the short-term prediction of airport terminal departure passenger traffic and the average error ranges from 1% to 3%. The difference between the predicted and the true values of passenger traffic flow is quite small, which indicates that the model has fairly good passenger traffic flow prediction ability.

Improved hydrological-model design by integrating nutrient and water flow

NASA Astrophysics Data System (ADS)

Arheimer, B.; Lindstrom, G.

2013-12-01

The potential of integrating hydrologic and nutrient concentration data to better understand patterns of catchment response and to better design hydrological modeling was explored using a national multi-basin model system for Sweden, called ';S-HYPE'. The model system covers more than 450 000 km2 and produce daily values of nutrient concentration and water discharge in 37 000 catchments from 1961 and onwards. It is based on the processed-based and semi-distributed HYdrological Predictions for the Environment (HYPE) code. The model is used operationally for assessments of water status or climate change impacts and for forecasts by the national warning service of floods, droughts and fire. The first model was launched in 2008, but S-HYPE is continuously improved and released in new versions every second year. Observations are available in 400 sites for daily water discharge and some 900 sites for monthly grab samples of nutrient concentrations. The latest version (2012) has an average NSE for water discharge of 0.7 and an average relative error of 5%, including both regulated and unregulated rivers with catchments from ten to several thousands of km2 and various landuse. The daily relative errors of nutrient concentrations are on average 20% for total Nitrogen and 35% for total Phosphorus. This presentation will give practical examples of how the nutrient data has been used to trace errors or inadequate parameter values in the hydrological model. Since 2008 several parts of the model structure has been reconsidered both in the source code, parameter values and input data of catchment characteristics. In this process water quality has been guiding much of the overall model design of catchment hydrological functions and routing along the river network. The model structure has thus been developed iteratively when evaluating results and checking time-series. Examples of water quality driven improvements will be given for estimation of vertical flow paths, such as separation of the hydrograph in surface flow, snow melt and baseflow, as well as horizontal flow paths in the landscape, such as mixing from various land use, impact from lakes and river channel volume. Overall, the S-HYPE model performance of water discharge increased from NSE 0.55 to 0.69 as an average for 400 gauges between the version 2010 and 2012. Most of this improvement, however, can be referred to improved regulations routines, rating curves for major lakes and parameters correcting ET and precipitation. Nevertheless, integrated water and nutrient modeling put constraints on the hydrological parameter values, which reduce equifinality for the hydrological part without reducing the model performance. The examples illustrates that the credibility of the hydrological model structure is thus improved by integrating water and nutrient flow. This lead to improved understanding of flow paths and water-nutrient process interactions in Sweden, which in turn will be very useful in further model analysis on impact of climate change or measures to reduce nutrient load from rivers to the Baltic Sea.

Temporal downscaling of decadal sediment load estimates to a daily interval for use in hindcast simulations

USGS Publications Warehouse

Ganju, N.K.; Knowles, N.; Schoellhamer, D.H.

2008-01-01

In this study we used hydrologic proxies to develop a daily sediment load time-series, which agrees with decadal sediment load estimates, when integrated. Hindcast simulations of bathymetric change in estuaries require daily sediment loads from major tributary rivers, to capture the episodic delivery of sediment during multi-day freshwater flow pulses. Two independent decadal sediment load estimates are available for the Sacramento/San Joaquin River Delta, California prior to 1959, but they must be downscaled to a daily interval for use in hindcast models. Daily flow and sediment load data to the Delta are available after 1930 and 1959, respectively, but bathymetric change simulations for San Francisco Bay prior to this require a method to generate daily sediment load estimates into the Delta. We used two historical proxies, monthly rainfall and unimpaired flow magnitudes, to generate monthly unimpaired flows to the Sacramento/San Joaquin Delta for the 1851-1929 period. This step generated the shape of the monthly hydrograph. These historical monthly flows were compared to unimpaired monthly flows from the modern era (1967-1987), and a least-squares metric selected a modern water year analogue for each historical water year. The daily hydrograph for the modern analogue was then assigned to the historical year and scaled to match the flow volume estimated by dendrochronology methods, providing the correct total flow for the year. We applied a sediment rating curve to this time-series of daily flows, to generate daily sediment loads for 1851-1958. The rating curve was calibrated with the two independent decadal sediment load estimates, over two distinct periods. This novel technique retained the timing and magnitude of freshwater flows and sediment loads, without damping variability or net sediment loads to San Francisco Bay. The time-series represents the hydraulic mining period with sustained periods of increased sediment loads, and a dramatic decrease after 1910, corresponding to a reduction in available mining debris. The analogue selection procedure also permits exploration of the morphological hydrograph concept, where a limited set of hydrographs is used to simulate the same bathymetric change as the actual set of hydrographs. The final daily sediment load time-series and morphological hydrograph concept will be applied as landward boundary conditions for hindcasting simulations of bathymetric change in San Francisco Bay.

SWB-A modified Thornthwaite-Mather Soil-Water-Balance code for estimating groundwater recharge

USGS Publications Warehouse

Westenbroek, S.M.; Kelson, V.A.; Dripps, W.R.; Hunt, R.J.; Bradbury, K.R.

2010-01-01

A Soil-Water-Balance (SWB) computer code has been developed to calculate spatial and temporal variations in groundwater recharge. The SWB model calculates recharge by use of commonly available geographic information system (GIS) data layers in combination with tabular climatological data. The code is based on a modified Thornthwaite-Mather soil-water-balance approach, with components of the soil-water balance calculated at a daily timestep. Recharge calculations are made on a rectangular grid of computational elements that may be easily imported into a regional groundwater-flow model. Recharge estimates calculated by the code may be output as daily, monthly, or annual values.

Myocardial blood flow quantification by Rb-82 cardiac PET/CT: A detailed reproducibility study between two semi-automatic analysis programs.

PubMed

Dunet, Vincent; Klein, Ran; Allenbach, Gilles; Renaud, Jennifer; deKemp, Robert A; Prior, John O

2016-06-01

Several analysis software packages for myocardial blood flow (MBF) quantification from cardiac PET studies exist, but they have not been compared using concordance analysis, which can characterize precision and bias separately. Reproducible measurements are needed for quantification to fully develop its clinical potential. Fifty-one patients underwent dynamic Rb-82 PET at rest and during adenosine stress. Data were processed with PMOD and FlowQuant (Lortie model). MBF and myocardial flow reserve (MFR) polar maps were quantified and analyzed using a 17-segment model. Comparisons used Pearson's correlation ρ (measuring precision), Bland and Altman limit-of-agreement and Lin's concordance correlation ρc = ρ·C b (C b measuring systematic bias). Lin's concordance and Pearson's correlation values were very similar, suggesting no systematic bias between software packages with an excellent precision ρ for MBF (ρ = 0.97, ρc = 0.96, C b = 0.99) and good precision for MFR (ρ = 0.83, ρc = 0.76, C b = 0.92). On a per-segment basis, no mean bias was observed on Bland-Altman plots, although PMOD provided slightly higher values than FlowQuant at higher MBF and MFR values (P < .0001). Concordance between software packages was excellent for MBF and MFR, despite higher values by PMOD at higher MBF values. Both software packages can be used interchangeably for quantification in daily practice of Rb-82 cardiac PET.

Expiratory flow limitation relates to symptoms during COPD exacerbations requiring hospital admission.

PubMed

Jetmalani, Kanika; Timmins, Sophie; Brown, Nathan J; Diba, Chantale; Berend, Norbert; Salome, Cheryl M; Wen, Fu-Qiang; Chen, Peng; King, Gregory G; Farah, Claude S

2015-01-01

Expiratory flow limitation (EFL) is seen in some patients presenting with a COPD exacerbation; however, it is unclear how EFL relates to the clinical features of the exacerbation. We hypothesized that EFL when present contributes to symptoms and duration of recovery during a COPD exacerbation. Our aim was to compare changes in EFL with symptoms in subjects with and without flow-limited breathing admitted for a COPD exacerbation. A total of 29 subjects with COPD were recruited within 48 hours of admission to West China Hospital for an acute exacerbation. Daily measurements of post-bronchodilator spirometry, resistance, and reactance using the forced oscillation technique and symptom (Borg) scores until discharge were made. Flow-limited breathing was defined as the difference between inspiratory and expiratory respiratory system reactance (EFL index) greater than 2.8 cmH2O·s·L(-1). The physiological predictors of symptoms during recovery were determined by mixed-effect analysis. Nine subjects (31%) had flow-limited breathing on admission despite similar spirometry compared to subjects without flow-limited breathing. Spirometry and resistance measures did not change between enrolment and discharge. EFL index values improved in subjects with flow-limited breathing on admission, with resolution in four patients. In subjects with flow-limited breathing on admission, symptoms were related to inspiratory resistance and EFL index values. In subjects without flow-limited breathing, symptoms related to forced expiratory volume in 1 second/forced vital capacity. In the whole cohort, EFL index values at admission was related to duration of stay (Rs=0.4, P=0.03). The presence of flow-limited breathing as well as abnormal respiratory system mechanics contribute independently to symptoms during COPD exacerbations.

Low-flow characteristics of streams in Ohio through water year 1997

USGS Publications Warehouse

Straub, David E.

2001-01-01

This report presents selected low-flow and flow-duration characteristics for 386 sites throughout Ohio. These sites include 195 long-term continuous-record stations with streamflow data through water year 1997 (October 1 to September 30) and for 191 low-flow partial-record stations with measurements into water year 1999. The characteristics presented for the long-term continuous-record stations are minimum daily streamflow; average daily streamflow; harmonic mean flow; 1-, 7-, 30-, and 90-day minimum average low flow with 2-, 5-, 10-, 20-, and 50-year recurrence intervals; and 98-, 95-, 90-, 85-, 80-, 75-, 70-, 60-, 50-, 40-, 30-, 20-, and 10-percent daily duration flows. The characteristics presented for the low-flow partial-record stations are minimum observed streamflow; estimated 1-, 7-, 30-, and 90-day minimum average low flow with 2-, 10-, and 20-year recurrence intervals; and estimated 98-, 95-, 90-, 85- and 80-percent daily duration flows. The low-flow frequency and duration analyses were done for three seasonal periods (warm weather, May 1 to November 30; winter, December 1 to February 28/29; and autumn, September 1 to November 30), plus the annual period based on the climatic year (April 1 to March 31).

Gazetteer of hydrologic characteristics of streams in Massachusetts; Blackstone River basin

USGS Publications Warehouse

Wandle, S.W.; Phipps, A.F.

1984-01-01

The Blackstone River basin encompasses 335 square miles in south-central Massachusetts, including parts of Bristol, Middlesex, Norfolk, and Worcester Counties. Drainage areas, using the latest available 1:24,000 scale topographic maps, were computed for the first time for streams draining more than 3 square miles and were recomputed for data-collection sites. Streamflow characteristics, were calculated using a new data base with records through 1980. These characteristics include annual and monthly flow statistics, duration of daily flow values, and the annual 7-day mean low flow at the 2-year and 10-year recurrence intervals. The 7-day, 10-year low-flow values are presented for 31 partial-record sites and the procedures used to determine the hydrologic characteristics of the basin are summarized. Basin characteristics representing 14 commonly used indices to estimate various streamflows are presented for the six gaged streams in the Blackstone River basin. This gazetteer will aid in the planning and siting of water-resources-related activities and will provide a common data base for governmental agencies and the engineering and planning communities. (USGS)

Scale appropriate modelling to represent dominant pollution processes in agricultural catchments, to underpin management and policy decisions

NASA Astrophysics Data System (ADS)

Adams, Russell; Quinn, Paul

2014-05-01

We present the development of scale appropriate modelling techniques to represent dominant pollution processes in agricultural catchments to underpin catchment management and its implications on policy. A quasi-physically based, spatially lumped macro-model (CRAFT), has been developed to assess mitigation options for nitrogen and phosphorus. CRAFT has been developed to use daily time series data of rainfall, stream flow and nutrient concentration data, and can be applied to catchments varying in size from a few hectares to 100s of square kilometres. If stream flow routing is added to the model then potentially larger catchments and sub-daily time steps could be represented. There are two key issues addressed here. Firstly, the model can be used to assess the usefulness of monitoring data collected at a high temporal resolution at considerable expense compared to routine grab sampling. An earlier study in the Frome catchment in southern England collected sub-daily water quality data for more than 12 months at the catchment outlet, comprising: total oxidised nitrogen (TON); soluble reactive phosphorus (SRP) and total phosphorus (TP) concentrations. The three data sets have quite different temporal signals relating to flow pathways with different residence times and the importance of runoff events in generating acute pollution. The flexible model structure was therefore developed to include different sources of runoff including overland flow from impervious areas in the catchment, where pollution hotspots will be located (e.g. farmyards). The model has been used to assess the value of collecting high resolution monitoring data, in this case by resampling the Frome sub-daily data to a daily timestep, and comparing these model simulations against those calibrated using all the samples. The usefulness of the high resolution data can be assessed on whether a daily model would undepredict (for example) high nutrient concentrations that can be identified in the sub-daily monitoring data. Secondly, the study aims to investigate the mitigation measures that can be used to address the catchment scale sources of N and P, under EU or other governmental legislation designed to reduce their loads. In a complex catchment like the Frome, the mitigation measures are likely to target both point and non-point sources, particularly of SRP (e.g. wastewater treatment plant discharges and soluble fertilizer applications respectively). For a modelling tool to be useful to land holders and policy makers, it is imperative that these stakeholders can investigate different scenarios by easily manipulating the model input parameters, e.g. by reducing the diffuse sources of SRP and TON (by parameter adjustment), or modifying flow pathways through runoff attenuation (e.g. reducing runoff from farmyards), and the model structure reflects this functionality allowing it to be used as a runoff attenuation tool.

A COMPREHENSIVE STUDY OF HOURLY AND DAILY SEWAGE FLOW RATES IN FLORIDA PUBLIC SCHOOLS.

ERIC Educational Resources Information Center

FOGARTY, WILLIAM J.; REEDER, MILTON E.

A DETERMINATION OF THE HOURLY AND DAILY SEWAGE FLOW RATES IN FLORIDA PUBLIC SCHOOLS WAS MADE TO IDENTIFY THE FLOW CHARACTERISTICS AND TO PROVIDE A MORE PRECISE BASIS FOR THE ESTABLISHMENT OF DESIGN CRITERIA FOR SEWAGE DISPOSAL FACILITIES IN SCHOOLS. WATER FLOW DATA WAS COLLECTED FOR 158 SCHOOLS AND SEWAGE FLOW DATA FROM 42 SCHOOLS. THE FINDINGS…

Scaling Erica arborea transpiration from trees up to the stand using auxiliary micrometeorological information in a wax myrtle-tree heath cloud forest (La Gomera, Canary Islands).

PubMed

Regalado, Carlos M; Ritter, Axel

2013-09-01

We investigate evapotranspiration, sap flow and top soil water content variations in a wax myrtle-tree heath ('fayal-brezal' in Spanish) cloud forest in the Garajonay National Park (La Gomera, Canary Islands) over a 1-year period. We provide transpiration estimates for one of the representative species, the shrubby needle-like Erica arborea L., present in this relict subtropical forest. An ad hoc tree up to the stand scaling method that combines the sap flow and auxiliary reference evapotranspiration data is illustrated, showing to be useful when sap flow in a limited number of trees has been monitored. Individual daily-based scaling curves of the Gompertz type were necessary to explain the observed sap flow variability in E. arborea during the 1-year period investigated (r(2) ≥ 0.953 with mode of r(2) = 0.9999). The mean daily sap flow of an E. arborea individual amounted to 8.37 ± 5.65 kg day(-1) tree(-1), with a maximum of 20.48 kg day(-1) tree(-1), yielding an annual total of 3052.89 kg tree(-1). A comparison of the computed daily transpiration with the continuous micrometeorological time series monitored in the studied plot suggested that solar radiation was the main driving force of transpiration in E. arborea (cross correlation index = 0.94). Fog may also affect tree transpiration via its reduction of radiation and temperature, such that during foggy periods the mean daily water loss estimate of E. arborea was 5.35 ± 4.30 kg day(-1) tree(-1), which sharply contrasted with the 2.4-fold average transpiration values obtained for fog-free days, i.e., 12.81 ± 4.33 kg day(-1) tree(-1). The annual water balance rendered a 288 mm year(-1) water input to the forest and evidenced the need for accurately quantifying the contribution of fog water dripping from the canopy.

Environmental controls on sap flow in black locust forest in Loess Plateau, China.

PubMed

Ma, Changkun; Luo, Yi; Shao, Mingan; Li, Xiangdong; Sun, Lin; Jia, Xiaoxu

2017-10-13

Black locust accounts for over 90% of artificial forests in China's Loess Plateau region. However, water use of black locust is an uphill challenge for this semi-arid region. To accurately quantify tree water use and to explain the related hydrological processes, it is important to collect reliable data for application in the estimation of sap flow and its response to environmental factors. This study measured sap flow in black locust in the 2015 and 2016 growth seasons using the thermal dissipation probes technique and laboratory-calibrated Granier's equation. The study showed that the laboratory calibrated coefficient α was much larger than the original value presented by Granier, while the coefficient β was similar to the original one. The average daily transpiration was 2.1 mm day -1 for 2015 and 1.6 mm day -1 for 2016. Net solar radiation (Rn) was the key meteorological factor controlling sap flow, followed by vapor pressure deficit (VPD) and then temperature (T). VPD had a threshold control on sap flow at threshold values of 1.9 kPa for 2015 and 1.6 kPa for 2016. The effects of diurnal hysteresis of Rn, VPD and T on sap flow were evident, indicating that black locust water use was conservative.

Regression equations to estimate seasonal flow duration, n-day high-flow frequency, and n-day low-flow frequency at sites in North Dakota using data through water year 2009

USGS Publications Warehouse

Williams-Sether, Tara; Gross, Tara A.

2016-02-09

Seasonal mean daily flow data from 119 U.S. Geological Survey streamflow-gaging stations in North Dakota; the surrounding states of Montana, Minnesota, and South Dakota; and the Canadian provinces of Manitoba and Saskatchewan with 10 or more years of unregulated flow record were used to develop regression equations for flow duration, n-day high flow and n-day low flow using ordinary least-squares and Tobit regression techniques. Regression equations were developed for seasonal flow durations at the 10th, 25th, 50th, 75th, and 90th percent exceedances; the 1-, 7-, and 30-day seasonal mean high flows for the 10-, 25-, and 50-year recurrence intervals; and the 1-, 7-, and 30-day seasonal mean low flows for the 2-, 5-, and 10-year recurrence intervals. Basin and climatic characteristics determined to be significant explanatory variables in one or more regression equations included drainage area, percentage of basin drainage area that drains to isolated lakes and ponds, ruggedness number, stream length, basin compactness ratio, minimum basin elevation, precipitation, slope ratio, stream slope, and soil permeability. The adjusted coefficient of determination for the n-day high-flow regression equations ranged from 55.87 to 94.53 percent. The Chi2 values for the duration regression equations ranged from 13.49 to 117.94, whereas the Chi2 values for the n-day low-flow regression equations ranged from 4.20 to 49.68.

Effects of nearshore recharge on groundwater interactions with a lake in mantled karst terrain

USGS Publications Warehouse

Lee, Terrie M.

2000-01-01

The recharge and discharge of groundwater were investigated for a lake basin in the mantled karst terrain of central Florida to determine the relative importance of transient groundwater inflow to the lake water budget. Variably saturated groundwater flow modeling simulated water table responses observed beneath two hillsides radiating outward from the groundwater flow‐through lake. Modeling results indicated that transient water table mounding and groundwater flow reversals in the nearshore region following large daily rainfall events generated most of the net groundwater inflow to the lake. Simulated daily groundwater inflow was greatest following water table mounding near the lake, not following subsequent peaks in the water level of upper basin wells. Transient mounding generated net groundwater inflow to the lake, that is, groundwater inflow in excess of the outflow occurring through the deeper lake bottom. The timing of the modeled net groundwater inflow agreed with an independent lake water budget; however, the quantity was considerably less than the budget‐derived value.

A Simple, Efficient and Effective Modeling Approach to Determine Baseflow Based on Concentration-Discharge Relationships

NASA Astrophysics Data System (ADS)

Liu, F.; Miller, M. P.; Conklin, M. H.

2017-12-01

Concentration-discharge relationships in streamflow are a precursor for diagnosing endmember mixing. With a strong power-law relationship between concentration and discharge, previous studies have shown that conservative solute concentrations in streamflow can be explained by mixing of two endmembers, i.e., quick runoff (QR) and baseflow (BF). This current study showed that the unique concentration-discharge power-law curve provides two characteristic values of solute concentrations at extremely high and low flows and these envelope values can be used to aid two-endmember mixing models. In an example conducted in the Upper Colorado River Basin (UCRB), daily specific conductance (SC) and discharge were strongly correlated by a power-law function on both rising and falling limbs from 1983 to 2015 (R2 > 0.9 for all years). The high envelope SC value in each year was directly used to characterize baseflow for that year, while the low envelope SC value was adjusted to represent quick runoff, a collective term for surface runoff and responsive shallow subsurface runoff. The peak flow was considered to be dominated by QR with only a small portion of BF. The ratio of minimum to maximum flows was used to calibrate the low envelope SC value. This ratio represents the least fraction of baseflow to total flow at the peak flow, as baseflow increases with total flow based on published studies. The SC value at the peak flow was considered to be a mixture of QR and BF with the minimum/maximum flow ratio as baseflow fraction and thus SC value in QR was determined with a mass balance equation. The baseflow fractions determined in two-endmember mixing models by this characterization of QR from 1983 to 2011 match those by Miller et al. [2014] very well (R2 = 0.96, slope = 1.07, intercept = -0.13). Baseflow fractions were slightly under-estimated by this approach mainly due to the fact that responsive shallow subsurface runoff was considered to be part of quick flow in this study rather than part of baseflow. This approach provides a simple, efficient and effective modeling tool for estimating baseflow without requiring any samples from endmembers in catchments with a strong power-law relation.

LFSTAT - An R-Package for Low-Flow Analysis

NASA Astrophysics Data System (ADS)

Koffler, D.; Laaha, G.

2012-04-01

When analysing daily streamflow data focusing on low flow and drought, the state of the art is well documented in the Manual on Low-Flow Estimation and Prediction [1] published by the WMO. While it is clear what has to be done, it is not so clear how to preform the analysis and make the calculation as reproducible as possible. Our software solution expands the high preforming statistical open source software package R to analyse daily stream flow data focusing on low-flows. As command-line based programs are not everyone's preference, we also offer a plug-in for the R-Commander, an easy to use graphical user interface (GUI) to analyse data in R. Functionality includes estimation of the most important low-flow indices. Beside standardly used flow indices also BFI and Recession constants can be computed. The main applications of L-moment based Extreme value analysis and regional frequency analysis (RFA) are available. Calculation of streamflow deficits is another important feature. The most common graphics are prepared and can easily be modified according to the users preferences. Graphics include hydrographs for different periods, flexible streamflow deficit plots, baseflow visualisation, flow duration curves as well as double mass curves just to name a few. The package uses a S3-class called lfobj (low-flow objects). Once this objects are created, analysis can be preformed by mouse-click, and a script can be saved to make the analysis easy reproducible. At the moment we are offering implementation of all major methods proposed in the WMO manual on Low-flow Estimation and Predictions. Future plans include e.g. report export in odt-file using odf-weave. We hope to offer a tool to ease and structure the analysis of stream flow data focusing on low-flows and to make analysis transparent and communicable. The package is designed for hydrological research and water management practice, but can also be used in teaching students the first steps in low-flow hydrology.

Evaporative water loss in man in a gravity-free environment

NASA Technical Reports Server (NTRS)

Leach, C. S.; Leonard, J. I.; Rambaut, P. C.; Johnson, P. C.

1978-01-01

Daily evaporative water losses (EWL) during the three Skylab missions were measured indirectly using mass and water-balance techniques. The mean daily values of EWL for the nine crew members who averaged 1 hr of daily exercise were: preflight 1,750 + or - 37 (SE) ml or 970 + or - 20 ml/sq m and inflight 1,560 + or - 26 ml or 860 + or - 14 ml/sq m. Although it was expected the EWL would increase in the hypobaric environment of Skylab, an average decrease from preflight sea-level conditions of 11% was measured. The results suggest that weightlessness decreased sweat losses during exercise and possibly reduced insensible skin losses. The weightlessness environment apparently promotes the formation of an observed sweat film on the skin surface during exercise by reducing convective flow and sweat drippage, resulting in high levels of skin wettedness that favor sweat suppression.

A comparison of the efficacy of ketotifen (HC 20-511) with sodium cromoglycate (SCG) in skin test positive asthma.

PubMed Central

Clarke, C W; May, C S

1980-01-01

1 Ketotifen (HC 20-511 Sandoz) 1 mg twice daily for 12 weeks was found to be equivalent to sodium cromoglycate (SCG) 20 mg four times daily for 12 weeks in 35 skin test positive asthmatic patients in a randomised double-blind cross-over study. 2 No statistically significant difference between the two drugs in mean values for daily peak flow rates, diary card scores and spirometry at monthly visits was demonstrated. 3 Treatment failures as judged by severe asthma requiring withdrawal from the trial or addition of short courses of prednisone occurred in three patients on each drug. 4 Sedation was noted by 10 patients onHC 20-511 and 5 on SCG. 5 Weight loss was noted in those patients on SCG, but not those on HC 20-511. PMID:6108129

A better understanding of long-range temporal dependence of traffic flow time series

NASA Astrophysics Data System (ADS)

Feng, Shuo; Wang, Xingmin; Sun, Haowei; Zhang, Yi; Li, Li

2018-02-01

Long-range temporal dependence is an important research perspective for modelling of traffic flow time series. Various methods have been proposed to depict the long-range temporal dependence, including autocorrelation function analysis, spectral analysis and fractal analysis. However, few researches have studied the daily temporal dependence (i.e. the similarity between different daily traffic flow time series), which can help us better understand the long-range temporal dependence, such as the origin of crossover phenomenon. Moreover, considering both types of dependence contributes to establishing more accurate model and depicting the properties of traffic flow time series. In this paper, we study the properties of daily temporal dependence by simple average method and Principal Component Analysis (PCA) based method. Meanwhile, we also study the long-range temporal dependence by Detrended Fluctuation Analysis (DFA) and Multifractal Detrended Fluctuation Analysis (MFDFA). The results show that both the daily and long-range temporal dependence exert considerable influence on the traffic flow series. The DFA results reveal that the daily temporal dependence creates crossover phenomenon when estimating the Hurst exponent which depicts the long-range temporal dependence. Furthermore, through the comparison of the DFA test, PCA-based method turns out to be a better method to extract the daily temporal dependence especially when the difference between days is significant.

Daily muscle stretching enhances blood flow, endothelial function, capillarity, vascular volume and connectivity in aged skeletal muscle.

PubMed

Hotta, Kazuki; Behnke, Bradley J; Arjmandi, Bahram; Ghosh, Payal; Chen, Bei; Brooks, Rachael; Maraj, Joshua J; Elam, Marcus L; Maher, Patrick; Kurien, Daniel; Churchill, Alexandra; Sepulveda, Jaime L; Kabolowsky, Max B; Christou, Demetra D; Muller-Delp, Judy M

2018-05-15

In aged rats, daily muscle stretching increases blood flow to skeletal muscle during exercise. Daily muscle stretching enhanced endothelium-dependent vasodilatation of skeletal muscle resistance arterioles of aged rats. Angiogenic markers and capillarity increased in response to daily stretching in muscles of aged rats. Muscle stretching performed with a splint could provide a feasible means of improving muscle blood flow and function in elderly patients who cannot perform regular aerobic exercise. Mechanical stretch stimuli alter the morphology and function of cultured endothelial cells; however, little is known about the effects of daily muscle stretching on adaptations of endothelial function and muscle blood flow. The present study aimed to determine the effects of daily muscle stretching on endothelium-dependent vasodilatation and muscle blood flow in aged rats. The lower hindlimb muscles of aged Fischer rats were passively stretched by placing an ankle dorsiflexion splint for 30 min day -1 , 5 days week -1 , for 4 weeks. Blood flow to the stretched limb and the non-stretched contralateral limb was determined at rest and during treadmill exercise. Endothelium-dependent/independent vasodilatation was evaluated in soleus muscle arterioles. Levels of hypoxia-induced factor-1α, vascular endothelial growth factor A and neuronal nitric oxide synthase were determined in soleus muscle fibres. Levels of endothelial nitric oxide synthase and superoxide dismutase were determined in soleus muscle arterioles, and microvascular volume and capillarity were evaluated by microcomputed tomography and lectin staining, respectively. During exercise, blood flow to plantar flexor muscles was significantly higher in the stretched limb. Endothelium-dependent vasodilatation was enhanced in arterioles from the soleus muscle from the stretched limb. Microvascular volume, number of capillaries per muscle fibre, and levels of hypoxia-induced factor-1α, vascular endothelial growth factor and endothelial nitric oxide synthase were significantly higher in the stretched limb. These results indicate that daily passive stretching of muscle enhances endothelium-dependent vasodilatation and induces angiogenesis. These microvascular adaptations may contribute to increased muscle blood flow during exercise in muscles that have undergone daily passive stretch. © 2018 The Authors. The Journal of Physiology © 2018 The Physiological Society.

Simulations of the north sea circulation, its variability, and its implementation as hydrodynamical forcing in ERSEM

NASA Astrophysics Data System (ADS)

Lenhart, Hermann J.; Radach, Günther; Backhaus, Jan O.; Pohlmann, Thomas

The rationale is given of how the gross physical features of the circulation and the stratification of the North Sea have been aggregated for inclusion in the ecosystem box model ERSEM. As the ecosystem dynamics are to a large extent determined by small-scale physical events, the ecosystem model is forced with the circulation of a specific year rather than using the long-term mean circulation field. Especially the vertical exchange processes have been explicitly included, because the primary production strongly depends on them. Simulations with a general circulation model (GCM), forced by three-hourly meteorological fields, have been utilized to derive daily horizontal transport values driving ERSEM on boxes of sizes of a few 100 km. The daily vertical transports across a fixed 30-m interface provide the necessary short-term event character of the vertical exchange. For the years 1988 and 1989 the properties of the hydrodynamic flow fields are presented in terms of trajectories of the flow, thermocline depths, of water budgets, flushing times and diffusion rates. The results of the standard simulation with ERSEM show that the daily variability of the circulation, being smoothed by the box integration procedure, is transferred to the chemical and biological state variables to a very limited degree only.

On the variability of cold region flooding

NASA Astrophysics Data System (ADS)

Matti, Bettina; Dahlke, Helen E.; Lyon, Steve W.

2016-03-01

Cold region hydrological systems exhibit complex interactions with both climate and the cryosphere. Improving knowledge on that complexity is essential to determine drivers of extreme events and to predict changes under altered climate conditions. This is particularly true for cold region flooding where independent shifts in both precipitation and temperature can have significant influence on high flows. This study explores changes in the magnitude and the timing of streamflow in 18 Swedish Sub-Arctic catchments over their full record periods available and a common period (1990-2013). The Mann-Kendall trend test was used to estimate changes in several hydrological signatures (e.g. annual maximum daily flow, mean summer flow, snowmelt onset). Further, trends in the flood frequency were determined by fitting an extreme value type I (Gumbel) distribution to test selected flood percentiles for stationarity using a generalized least squares regression approach. Results highlight shifts from snowmelt-dominated to rainfall-dominated flow regimes with all significant trends (at the 5% significance level) pointing toward (1) lower magnitudes in the spring flood; (2) earlier flood occurrence; (3) earlier snowmelt onset; and (4) decreasing mean summer flows. Decreasing trends in flood magnitude and mean summer flows suggest widespread permafrost thawing and are supported by increasing trends in annual minimum daily flows. Trends in selected flood percentiles showed an increase in extreme events over the full periods of record (significant for only four catchments), while trends were variable over the common period of data among the catchments. An uncertainty analysis emphasizes that the observed trends are highly sensitive to the period of record considered. As such, no clear overall regional hydrological response pattern could be determined suggesting that catchment response to regionally consistent changes in climatic drivers is strongly influenced by their physical characteristics.

Daily water-temperature records for Utah streams, 1944-68

USGS Publications Warehouse

Whitaker, G.L.

1970-01-01

Temperature is an important and sometimes critical factor for many uses of water. Temperature affects the usefulness of the water for recreation, fish and wildlife propagation, industrial cooling, food processing, and manufacturing. Temperature also affects the ability of the water to accommodate biologic and vegetative types of life.The purpose of this report is to summarize in tabular form the water- temperature data that have been collected by the U.S. Geological Survey on a daily basis for streams in Utah. A few stream sites near the boundaries of Utah in neighboring States have been included. These sites are on streams which either flow out of or into Utah, and they may provide information of value in studies dealing with water quality in the State.

Application of acoustical methods for estimating water flow and constituent loads in Perdido Bay, Florida

USGS Publications Warehouse

Grubbs, J.W.; Pittman, J.R.

1997-01-01

Water flow and quality data were collected from December 1994 to September 1995 to evaluate variations in discharge, water quality, and chemical fluxes (loads) through Perdido Bay, Florida. Data were collected at a cross section parallel to the U.S. Highway 98 bridge. Discharges measured with an acoustic Doppler current profiler (ADCP) and computed from stage-area and velocity ratings varied roughly between + or - 10,000 cubic feet per second during a typical tidal cycle. Large reversals in flow direction occurred rapidly (less than 1 hour), and complete reversals (resulting in near peak net-upstream or downstream discharges) occurred within a few hours of slack water. Observations of simultaneous upstream and downstream flow (bidirectional flow) were quite common in the ADCP measurements, with opposing directions of flow occurring predominantly in vertical layers. Continuous (every 15 minutes) discharge data were computed for the period from August 18, 1995, to September 28, 1995, and filtered daily mean discharge values were computed for the period from August 19 to September 26, 1995. Data were not computed prior to August 18, 1995, either because of missing data or because the velocity rating was poorly defined (because of insufficient data) for the period prior to landfall of hurricane Erin (August 3, 1995). The results of the study indicate that acoustical techniques can yield useful estimates of continuous (instantaneous) discharge in Perdido Bay. Useful estimates of average daily net flow rates can also be obtained, but the accuracy of these estimates will be limited by small rating shifts that introduce bias into the instantaneous values that are used to compute the net flows. Instantaneous loads of total nitrogen ranged from -180 to 220 grams per second for the samples collected during the study, and instantaneous loads of total phosphorous ranged from -10 to 11 grams per second (negative loads indicate net upstream transport). The chloride concentrations from the water samples collected from Perdido Bay indicated a significant amount of mixing of saltwater and freshwater. Mixing effects could greatly reduce the accuracy of estimates of net loads of nutrients or other substances. The study results indicate that acoustical techniques can yield acceptable estimates of instantaneous loads in Perdido Bay. However, estimates of net loads should be interpreted with great caution and may have unacceptably large errors, especially when saltwater and freshwater concentrations differ greatly.

Ion release from dental casting alloys as assessed by a continuous flow system: Nutritional and toxicological implications.

PubMed

López-Alías, José F; Martinez-Gomis, Jordi; Anglada, Josep M; Peraire, Maria

2006-09-01

The aims of this study were to quantify the metallic ions released by various dental alloys subjected to a continuous flow of saliva and to estimate the nutritional and toxicological implications of such a release. Four pieces of three nickel-based, one noble, one high-noble and two copper-aluminum alloys were cast and then immersed in a continuous flow of artificial saliva for 15 days. To simulate three meals a day, casts were subjected to thrice-daily episodes, lasting 30 min each and consisting of pH decreases and salinity increases. After 15 days, the metallic ions in the artificial saliva were analyzed. Data were expressed as averaged release rate: microg/cm2/day of ion released for each alloy. The highest value of 95% Cl of each ion was adapted to a hypothetical worst scenario of a subject with 100 cm2 of exposed metal surface. The results were compared with the tolerable upper daily intake level of each ion. The copper-aluminum alloys released copper, aluminum, nickel, manganese and iron. The nickel-based alloys essentially released nickel and chromium, while the beryllium-containing alloy released beryllium and significantly more nickel. The noble and high-noble alloys were very resistant to corrosion. The amount of ions released remained far below the upper tolerable intake level, with the exception of nickel, released by beryllium-containing nickel-based alloy, whose levels approach 50% of this threshold. The daily amount of ions released seems to be far below the tolerable upper intake levels for each ion.

Simulation of net infiltration and potential recharge using a distributed-parameter watershed model of the Death Valley region, Nevada and California

USGS Publications Warehouse

Hevesi, Joseph A.; Flint, Alan L.; Flint, Lorraine E.

2003-01-01

This report presents the development and application of the distributed-parameter watershed model, INFILv3, for estimating the temporal and spatial distribution of net infiltration and potential recharge in the Death Valley region, Nevada and California. The estimates of net infiltration quantify the downward drainage of water across the lower boundary of the root zone and are used to indicate potential recharge under variable climate conditions and drainage basin characteristics. Spatial variability in recharge in the Death Valley region likely is high owing to large differences in precipitation, potential evapotranspiration, bedrock permeability, soil thickness, vegetation characteristics, and contributions to recharge along active stream channels. The quantity and spatial distribution of recharge representing the effects of variable climatic conditions and drainage basin characteristics on recharge are needed to reduce uncertainty in modeling ground-water flow. The U.S. Geological Survey, in cooperation with the Department of Energy, developed a regional saturated-zone ground-water flow model of the Death Valley regional ground-water flow system to help evaluate the current hydrogeologic system and the potential effects of natural or human-induced changes. Although previous estimates of recharge have been made for most areas of the Death Valley region, including the area defined by the boundary of the Death Valley regional ground-water flow system, the uncertainty of these estimates is high, and the spatial and temporal variability of the recharge in these basins has not been quantified. To estimate the magnitude and distribution of potential recharge in response to variable climate and spatially varying drainage basin characteristics, the INFILv3 model uses a daily water-balance model of the root zone with a primarily deterministic representation of the processes controlling net infiltration and potential recharge. The daily water balance includes precipitation (as either rain or snow), snow accumulation, sublimation, snowmelt, infiltration into the root zone, evapotranspiration, drainage, water content change throughout the root-zone profile (represented as a 6-layered system), runoff (defined as excess rainfall and snowmelt) and surface water run-on (defined as runoff that is routed downstream), and net infiltration (simulated as drainage from the bottom root-zone layer). Potential evapotranspiration is simulated using an hourly solar radiation model to simulate daily net radiation, and daily evapotranspiration is simulated as an empirical function of root zone water content and potential evapotranspiration. The model uses daily climate records of precipitation and air temperature from a regionally distributed network of 132 climate stations and a spatially distributed representation of drainage basin characteristics defined by topography, geology, soils, and vegetation to simulate daily net infiltration at all locations, including stream channels with intermittent streamflow in response to runoff from rain and snowmelt. The temporal distribution of daily, monthly, and annual net infiltration can be used to evaluate the potential effect of future climatic conditions on potential recharge. The INFILv3 model inputs representing drainage basin characteristics were developed using a geographic information system (GIS) to define a set of spatially distributed input parameters uniquely assigned to each grid cell of the INFILv3 model grid. The model grid, which was defined by a digital elevation model (DEM) of the Death Valley region, consists of 1,252,418 model grid cells with a uniform grid cell dimension of 278.5 meters in the north-south and east-west directions. The elevation values from the DEM were used with monthly regression models developed from the daily climate data to estimate the spatial distribution of daily precipitation and air temperature. The elevation values were also used to simulate atmosp

Regionalized rainfall-runoff model to estimate low flow indices

NASA Astrophysics Data System (ADS)

Garcia, Florine; Folton, Nathalie; Oudin, Ludovic

2016-04-01

Estimating low flow indices is of paramount importance to manage water resources and risk assessments. These indices are derived from river discharges which are measured at gauged stations. However, the lack of observations at ungauged sites bring the necessity of developing methods to estimate these low flow indices from observed discharges in neighboring catchments and from catchment characteristics. Different estimation methods exist. Regression or geostatistical methods performed on the low flow indices are the most common types of methods. Another less common method consists in regionalizing rainfall-runoff model parameters, from catchment characteristics or by spatial proximity, to estimate low flow indices from simulated hydrographs. Irstea developed GR2M-LoiEau, a conceptual monthly rainfall-runoff model, combined with a regionalized model of snow storage and melt. GR2M-LoiEau relies on only two parameters, which are regionalized and mapped throughout France. This model allows to cartography monthly reference low flow indices. The inputs data come from SAFRAN, the distributed mesoscale atmospheric analysis system, which provides daily solid and liquid precipitation and temperature data from everywhere in the French territory. To exploit fully these data and to estimate daily low flow indices, a new version of GR-LoiEau has been developed at a daily time step. The aim of this work is to develop and regionalize a GR-LoiEau model that can provide any daily, monthly or annual estimations of low flow indices, yet keeping only a few parameters, which is a major advantage to regionalize them. This work includes two parts. On the one hand, a daily conceptual rainfall-runoff model is developed with only three parameters in order to simulate daily and monthly low flow indices, mean annual runoff and seasonality. On the other hand, different regionalization methods, based on spatial proximity and similarity, are tested to estimate the model parameters and to simulate low flow indices in ungauged sites. The analysis is carried out on 691 French catchments that are representative of various hydro-meteorological behaviors. The results are validated with a cross-validation procedure and are compared with the ones obtained with GR4J, a conceptual rainfall-runoff model, which already provides daily estimations, but involves four parameters that cannot easily be regionalized.

Evaluation of a method of estimating low-flow frequencies from base-flow measurements at Indiana streams

USGS Publications Warehouse

Wilson, John Thomas

2000-01-01

A mathematical technique of estimating low-flow frequencies from base-flow measurements was evaluated by using data for streams in Indiana. Low-flow frequencies at low- flow partial-record stations were estimated by relating base-flow measurements to concurrent daily flows at nearby streamflow-gaging stations (index stations) for which low-flowfrequency curves had been developed. A network of long-term streamflow-gaging stations in Indiana provided a sample of sites with observed low-flow frequencies. Observed values of 7-day, 10-year low flow and 7-day, 2-year low flow were compared to predicted values to evaluate the accuracy of the method. Five test cases were used to evaluate the method under a variety of conditions in which the location of the index station and its drainage area varied relative to the partial-record station. A total of 141 pairs of streamflow-gaging stations were used in the five test cases. Four of the test cases used one index station, the fifth test case used two index stations. The number of base-flow measurements was varied for each test case to see if the accuracy of the method was affected by the number of measurements used. The most accurate and least variable results were produced when two index stations on the same stream or tributaries of the partial-record station were used. All but one value of the predicted 7-day, 10-year low flow were within 15 percent of the values observed for the long-term continuous record, and all of the predicted values of the 7-day, 2-year lowflow were within 15 percent of the observed values. This apparent accuracy, to some extent, may be a result of the small sample set of 15. Of the four test cases that used one index station, the most accurate and least variable results were produced in the test case where the index station and partial-record station were on the same stream or on streams tributary to each other and where the index station had a larger drainage area than the partial-record station. In that test case, the method tended to over predict, based on the median relative error. In 23 of 28 test pairs, the predicted 7-day, 10-year low flow was within 15 percent of the observed value; in 26 of 28 test pairs, the predicted 7-day, 2-year low flow was within 15 percent of the observed value. When the index station and partial-record station were on the same stream or streams tributary to each other and the index station had a smaller drainage area than the partial-record station, the method tended to under predict the low-flow frequencies. Nineteen of 28 predicted values of the 7-day, 10-year low flow were within 15 percent of the observed values. Twenty-five of 28 predicted values of the 7-day, 2-year low flow were within 15 percent of the observed values. When the index station and the partial-record station were on different streams, the method tended to under predict regardless of whether the index station had a larger or smaller drainage area than that of the partial-record station. Also, the variability of the relative error of estimate was greatest for the test cases that used index stations and partial-record stations from different streams. This variability, in part, may be caused by using more streamflow-gaging stations with small low-flow frequencies in these test cases. A small difference in the predicted and observed values can equate to a large relative error when dealing with stations that have small low-flow frequencies. In the test cases that used one index station, the method tended to predict smaller low-flow frequencies as the number of base-flow measurements was reduced from 20 to 5. Overall, the average relative error of estimate and the variability of the predicted values increased as the number of base-flow measurements was reduced.

The use of broken power-laws to describe the distributions of daily flow above the mean annual flow across the conterminous U.S.

Treesearch

Catalina Segura; Davide Lazzati; Arumugam Sankarasubramanian

2013-01-01

A recent study employed a broken power-law (BPL) distribution for understanding the scaling frequency of bankfull discharge in snowmelt-dominated basins. This study, grounded from those findings, investigated the ability of a BPL function to describe the distribution of daily flows above the mean annual flow in 1217 sites across the conterminous U.S. (CONUS). The...

Estimation of natural historical flows for the Manitowish River near Manitowish Waters, Wisconsin

USGS Publications Warehouse

Juckem, Paul F.; Reneau, Paul C.; Robertson, Dale M.

2012-01-01

The Wisconsin Department of Natural Resources is charged with oversight of dam operations throughout Wisconsin and is considering modifications to the operating orders for the Rest Lake Dam in Vilas County, Wisconsin. State law requires that the operation orders be tied to natural low flows at the dam. Because the presence of the dam confounds measurement of natural flows, the U.S. Geological Survey, in cooperation with the Wisconsin Department of Natural Resources, installed streamflow-gaging stations and developed two statistical methods to improve estimates of natural flows at the Rest Lake Dam. Two independent methods were used to estimate daily natural flow for the Manitowish River approximately 1 mile downstream of the Rest Lake Dam. The first method was an adjusted drainage-area ratio method, which used a regression analysis that related measured water yield (flow divided by watershed area) from short-term (2009–11) gaging stations upstream of the Manitowish Chain of Lakes to the water yield from two nearby long-term gaging stations in order to extend the flow record (1991–2011). In this approach, the computed flows into the Chain of Lakes at the upstream gaging stations were multiplied by a coefficient to account for the monthly hydrologic contributions (precipitation, evaporation, groundwater, and runoff) associated with the additional watershed area between the upstream gaging stations and the dam at the outlet of the Chain of Lakes (Rest Lake Dam). The second method used to estimate daily natural flow at the Rest Lake Dam was a water-budget approach, which used lake stage and dam outflow data provided by the dam operator. A water-budget model was constructed and then calibrated with an automated parameter-estimation program by matching simulated flow-duration statistics with measured flow-duration statistics at the upstream gaging stations. After calibration of the water-budget model, the model was used to compute natural flow at the dam from 1973 to 2011. Daily natural flows at the dam, as computed by the adjusted drainage-area ratio method and the water-budget method, were used to compute monthly flow-duration values for the period of historical data available for each method. Monthly flow-durations provide a means for evaluating the frequency and range in flows that have been observed for each month over the course of many years. Both methods described the pattern and timing of measured high-flow and low-flow events at the upstream gaging stations. The adjusted drainage-area ratio method generally had smaller residual errors across the full range of observed flows and had smaller monthly biases than the water-budget method. Although it is not possible to evaluate which method may be more "correct" for estimating monthly natural flows at the dam, comparisons between the results of each method indicate that the adjusted drainage-area ratio method may be susceptible to biases at high flows due to isolated storms outside of the Manitowish River watershed. Conversely, it appears that the water-budget method may be susceptible to biases at low flows because of its sensitivity to the accuracy of reported lake stage and outflows, as well as effects of upstream diversions that could not be fully compensated for with this method. Results from both methods are useful for understanding the natural flow patterns at the dam. Flows for both methods have similar patterns, with high median flows in spring and low median flows in late summer. Similarly, the range from monthly high-flow durations to low-flow durations increases during spring, decreases during summer, and increases again during fall. These seasonal patterns illustrate a challenge with interpreting a single value of natural low flow. That is, a natural low flow computed for September is not representative of a natural low flow in April. Moreover, alteration of natural flows caused by storing water in the Chain of Lakes during spring and releasing it in fall causes a change in the timing of high and low flows compared with natural conditions. That is, the lowest reported dam outflows occurred in spring and highest reported outflows occurred in fall, which is opposite the natural patterns.

Advice on lifestyle changes (diet, red wine and physical activity) does not affect internal carotid and middle cerebral artery blood flow velocity in patients with carotid arteriosclerosis in a randomized controlled trial.

PubMed

Droste, Dirk W; Iliescu, Catalina; Vaillant, Michel; Gantenbein, Manon; De Bremaeker, Nancy; Lieunard, Charlotte; Velez, Telma; Meyer, Michèle; Guth, Tessy; Kuemmerle, Andrea; Chioti, Anna

2014-01-01

A Mediterranean diet, with and without small daily amounts of red wine, and physical activity reduce the risk of cerebrovascular disease and improve cognition. An increase in cerebral blood flow may be the underlying mechanism. Under normal conditions, cerebral blood flow velocity changes in the internal carotid arteries and in large basal cerebral arteries correlate closely with cerebral blood flow changes, as the diameter of these vessels hardly changes and only the smaller vessels downstream change their diameter. A prospective randomized controlled trial was performed in 108 patients with carotid atherosclerosis (mean age 64 years, 67% men, 66% on statin therapy). Half of them were advised to follow a polyphenol-rich modified Mediterranean diet including 1-2 tomatoes, 3-5 walnuts and a bar of dark chocolate (25 g) a day and to perform moderate physical exercise for 30 min/day (lifestyle changes). Within these two groups, half of the patients were randomized either to avoid any alcohol or to drink 100 ml of red wine (women) or 200 ml of red wine (men) daily. Bilateral middle cerebral and internal carotid blood flow velocity (peak systolic, peak end-diastolic and mean) was measured at baseline and after 4 and 20 weeks using colour-coded duplex ultrasound. Insonation depth and insonation angle were used to identically place the sample volume during follow-up investigations. A general linear model with Tukey-Kramer adjustment for multiple comparisons was used to assess the primary end points. For the analysis we used the mean values of the right and left artery. Neither lifestyle changes nor red wine had an effect on peak systolic, peak end-diastolic or mean cerebral blood flow velocity. Advice on lifestyle changes, including a modified polyphenol-rich Mediterranean diet, a glass of red wine daily and physical exercise, did not affect middle cerebral and internal carotid blood flow velocity in our patient group with carotid atherosclerosis. An increase in cerebral blood flow is thus unlikely to be the cause of the reduced risk of cerebrovascular disease and improved cognitive functioning described in the literature. One possible explanation for the fact that blood flow velocity was not affected by red wine, diet and physical activity advice is that two thirds of our patients were already on statin therapy. Statins increase cerebral blood flow and vasomotor reactivity via nitric oxide. © 2014 S. Karger AG, Basel.

Antecedent flow conditions and nitrate concentrations in the Mississippi River basin

USGS Publications Warehouse

Murphy, Jennifer C.; Hirsch, Robert M.; Sprague, Lori A.

2014-01-01

The relationship between antecedent flow conditions and nitrate concentrations was explored at eight sites in the 2.9 million square kilometers (km2) Mississippi River basin, USA. Antecedent flow conditions were quantified as the ratio between the mean daily flow of the previous year and the mean daily flow from the period of record (Qratio), and the Qratio was statistically related to nitrate anomalies (the unexplained variability in nitrate concentration after filtering out season, long-term trend, and contemporaneous flow effects) at each site. Nitrate anomaly and Qratio were negatively related at three of the four major tributary sites and upstream in the Mississippi River, indicating that when mean daily streamflow during the previous year was lower than average, nitrate concentrations were higher than expected. The strength of these relationships increased when data were subdivided by contemporaneous flow conditions. Five of the eight sites had significant negative relationships (p ≤ 0.05) at high or moderately high contemporaneous flows, suggesting nitrate that accumulates in these basins during a drought is flushed during subsequent high flows. At half of the sites, when mean daily flow during the previous year was 50 percent lower than average, nitrate concentration can be from 9 to 27 percent higher than nitrate concentrations that follow a year with average mean daily flow. Conversely, nitrate concentration can be from 8 to 21 percent lower than expected when flow during the previous year was 50 percent higher than average. Previously documented for small, relatively homogenous basins, our results suggest that relationships between antecedent flows and nitrate concentrations are also observable at a regional scale. Relationships were not observed (using all contemporaneous flow data together) for basins larger than 1 million km2, suggesting that above this limit the overall size and diversity within these basins may necessitate the use of more complicated statistical approaches or that there may be no discernible basin-wide relationship with antecedent flow. The relationships between nitrate concentration and Qratio identified in this study serve as the basis for future studies that can better define specific hydrologic processes occurring during and after a drought (or high flow period) which influence nitrate concentration, such as the duration or magnitude of low flows, and the timing of low and high flows.

Increased dry season water yield in burned watersheds in Southern California

NASA Astrophysics Data System (ADS)

Kinoshita, Alicia M.; Hogue, Terri S.

2015-01-01

The current work evaluates the effects of the 2003 Old Fire on semi-arid systems in the San Bernardino Mountains, California. Pre- and post-fire daily streamflow are used to analyze flow regimes in two burned watersheds. The average pre-fire runoff ratios in Devil Canyon and City Creek are 0.14 and 0.26, respectively, and both increase to 0.34 post-fire. Annual flow duration curves are developed for each watershed and the low flow is characterized by a 90% exceedance probability threshold. Post-fire low flow is statistically different from the pre-fire values (α = 0.05). In Devil Canyon the annual volume of pre-fire low flow increases on average from 2.6E + 02 to 3.1E + 03 m3 (1090% increase) and in City Creek the annual low flow volume increases from 2.3E + 03 to 5.0E + 03 m3 (118% increase). Predicting burn system resilience to disturbance (anthropogenic and natural) has significant implications for water sustainability and ultimately may provide an opportunity to utilize extended and increased water yield.

A nonparametric stochastic method for generating daily climate-adjusted streamflows

NASA Astrophysics Data System (ADS)

Stagge, J. H.; Moglen, G. E.

2013-10-01

A daily stochastic streamflow generation model is presented, which successfully replicates statistics of the historical streamflow record and can produce climate-adjusted daily time series. A monthly climate model relates general circulation model (GCM)-scale climate indicators to discrete climate-streamflow states, which in turn control parameters in a daily streamflow generation model. Daily flow is generated by a two-state (increasing/decreasing) Markov chain, with rising limb increments randomly sampled from a Weibull distribution and the falling limb modeled as exponential recession. When applied to the Potomac River, a 38,000 km2 basin in the Mid-Atlantic United States, the model reproduces the daily, monthly, and annual distribution and dynamics of the historical streamflow record, including extreme low flows. This method can be used as part of water resources planning, vulnerability, and adaptation studies and offers the advantage of a parsimonious model, requiring only a sufficiently long historical streamflow record and large-scale climate data. Simulation of Potomac streamflows subject to the Special Report on Emissions Scenarios (SRES) A1b, A2, and B1 emission scenarios predict a slight increase in mean annual flows over the next century, with the majority of this increase occurring during the winter and early spring. Conversely, mean summer flows are projected to decrease due to climate change, caused by a shift to shorter, more sporadic rain events. Date of the minimum annual flow is projected to shift 2-5 days earlier by the 2070-2099 period.

Regional flow duration curves: Geostatistical techniques versus multivariate regression

USGS Publications Warehouse

Pugliese, Alessio; Farmer, William H.; Castellarin, Attilio; Archfield, Stacey A.; Vogel, Richard M.

2016-01-01

A period-of-record flow duration curve (FDC) represents the relationship between the magnitude and frequency of daily streamflows. Prediction of FDCs is of great importance for locations characterized by sparse or missing streamflow observations. We present a detailed comparison of two methods which are capable of predicting an FDC at ungauged basins: (1) an adaptation of the geostatistical method, Top-kriging, employing a linear weighted average of dimensionless empirical FDCs, standardised with a reference streamflow value; and (2) regional multiple linear regression of streamflow quantiles, perhaps the most common method for the prediction of FDCs at ungauged sites. In particular, Top-kriging relies on a metric for expressing the similarity between catchments computed as the negative deviation of the FDC from a reference streamflow value, which we termed total negative deviation (TND). Comparisons of these two methods are made in 182 largely unregulated river catchments in the southeastern U.S. using a three-fold cross-validation algorithm. Our results reveal that the two methods perform similarly throughout flow-regimes, with average Nash-Sutcliffe Efficiencies 0.566 and 0.662, (0.883 and 0.829 on log-transformed quantiles) for the geostatistical and the linear regression models, respectively. The differences between the reproduction of FDC's occurred mostly for low flows with exceedance probability (i.e. duration) above 0.98.

Desagregation des debits mensuels en debits journaliers

NASA Astrophysics Data System (ADS)

Ypou, Tanou Ya Kouassi

A good estimate of the historical natural flow of water in a water system, allows an appropriate management of reservoirs of hydroelectric plants. This management is a guarantee for efficient planning of hydropower production. The reconstruction of the real natural inputs with quality features for the periods before and after the impoundment of reservoirs is sought by HQ. The implementation of a good quality daily historical data from monthly data remains a major concern both for HQ and for the scientific community. Beyond the benefits of mastering simulations of the basin's hydrological behavior in water systems, this study allows the establishment of appropriate measures to protect the population and the various properties located in riparian areas of water systems. The main objective of the study is the breakdown of monthly flows in daily flows. This study is in the business context of HQ. To reconstruct the historical supply of water systems, HSAMI and HYDROTEL models are used. Different methods have been used by HQ to constitute the daily historical rates. So far, a good quality of the reconstituted daily data analysis illustrates the serious discrepancies and errors in those series. Several previous studies in the literature have attempted to reconstruct the daily flow rates from historical monthly series, but as explained in the report, these different approaches have results that do not represent the reality of HQ's water systems. Clearly the methods are not effective in the operational framework of Hydro-Quebec. This report presents an optimized use based on the approach HSAMI and HYDROTEL models in order to transform the flow of rain for the reconstruction of natural flow series. This approach is applied to Outardes's and Saint-Maurice's water systems with the weather and physical field data available. Input the hydrological data are validated by a process of analyzing data quality, specific flow and evaporation parameters. Input the metrological data has been analysis by Statistics, climate and water for weather series criteria. An automatic calibration of the two models is made with the Matlab software. The results of the calibration of Outardes's and Saint-Maurice's water systems are presented in this report. The modeling of ground conditions is made for input data needs of different models using the features included in the models are generally presented in this report and in particularly the model for HYDROTEL and PHYSITEL. The historical simulation flows is performed using meteorological data and physical field data on the periods of 1965 to 2014. Based on the quality of input data available and the goal of generating daily historical supply series using monthly series of natural inputs, the quality criteria have been defined to qualify the model to choose. Indeed, the quality criteria for comparing the two models are the criterion of NSE and KGE. Analysis of the results led to the conclusion that the HYDROTEL model is most appropriate in the operational framework of HQ to disaggregate monthly historical series of daily flows in series. The HYDROTEL model enabled to disaggregate monthly debits daily flows. The daily discharges simulated ponds Beaumont, Vermillion, La tuque are presented and analyzed in this report. Keywords: disaggregation, natural flow, HYDROTEL, HSAMI, data reconstruction .

Estimating Low-Flow Frequency Statistics and Hydrologic Analysis of Selected Streamflow-Gaging Stations, Nooksack River Basin, Northwestern Washington and Canada

USGS Publications Warehouse

Curran, Christopher A.; Olsen, Theresa D.

2009-01-01

Low-flow frequency statistics were computed at 17 continuous-record streamflow-gaging stations and 8 miscellaneous measurement sites in and near the Nooksack River basin in northwestern Washington and Canada, including the 1, 3, 7, 15, 30, and 60 consecutive-day low flows with recurrence intervals of 2 and 10 years. Using these low-flow statistics, 12 regional regression equations were developed for estimating the same low-flow statistics at ungaged sites in the Nooksack River basin using a weighted-least-squares method. Adjusted R2 (coefficient of determination) values for the equations ranged from 0.79 to 0.93 and the root-mean-squared error (RMSE) expressed as a percentage ranged from 77 to 560 percent. Streamflow records from six gaging stations located in mountain-stream or lowland-stream subbasins of the Nooksack River basin were analyzed to determine if any of the gaging stations could be removed from the network without significant loss of information. Using methods of hydrograph comparison, daily-value correlation, variable space, and flow-duration ratios, and other factors relating to individual subbasins, the six gaging stations were prioritized from most to least important as follows: Skookum Creek (12209490), Anderson Creek (12210900), Warm Creek (12207750), Fishtrap Creek (12212050), Racehorse Creek (12206900), and Clearwater Creek (12207850). The optimum streamflow-gaging station network would contain all gaging stations except Clearwater Creek, and the minimum network would include Skookum Creek and Anderson Creek.

The relation between cerebral blood flow velocities as measured by TCD and the incidence of delayed ischemic deficits. A prospective study after subarachnoid hemorrhage.

PubMed

Jarus-Dziedzic, Katarzyna; Juniewicz, Henryk; Wroñski, Jerzy; Zub, Wojciech Leslaw; Kasper, Ekkehard; Gowacki, Mariusz; Mierzwa, Janusz

2002-09-01

Patients (n = 127) with aneurysmal subarachnoid hemorrhage (SAH) were examined by transcranial Doppler ultrasonography (TCD) in a prospective study to follow the time course of the posthemorrhagic blood flow velocity in both the middle cerebral artery (MCA) and in the anterior cerebral artery (ACA). Results were analysed to reveal their relationship and predictive use with respect to the occurrence of delayed ischemic deficits. Mean flow velocities (MFV) higher than 120 cm sec(-1) in MCA and 90 cm sec(-1) in ACA were interpreted as indicative for significant vasospasm. In 20 of our 127 patients (16%) a delayed ischemic deficit (DID) was subsequently diagnosed clinically (DID+ group). Patients in the DID+ group can be characterized as those individuals who presented early during the observation period post-SAH with highest values of MFV, a faster increase and longer persistence of pathologically elevated MFV-values (exceeding 120 cm sec(-1) in MCA and 90 cm sec(-1) in ACA). They also show a greater difference in MFV-values if one compares the operated to the nonoperated side. Differences in MFV-values obtained in MCA or ACA were statistically significant (p < 0.05) for DID+ and DID- patients. The daily maximal increase of MFV was found between days 9 and 11 after SAH. In the DID+ group, the maximal MFV was 181 +/- 26 cm sec(-1) in MCA and 119 +/- 14 cm sec(-1) in ACA. In contrast to this, patients in the DID- group were found to present with MFV of 138 +/- 11 cm sec(-1) in MCA and 100 +/- 7 cm sec(-1) in ACA respectively. Delayed ischemic deficits appeared three times more often in DID+ patients than in patients with MFV < 120 cm sec(-1), if they showed a MFV > 120 cm sec(-1) in MCA. If pathological values were obtained in ACA, this ratio increases to about four times, if DID + patients presented with MFV > 90 cm sec(-1) versus patients with MFV < 90 cm sec(-1). Daily monitoring of vasospasm using TCD examination is thus helpful to identify patients at high risk for delayed ischemic deficits. This should allow us to implement further preventive treatment regimens.

Predicting nitrate discharge dynamics in mesoscale catchments using the lumped StreamGEM model and Bayesian parameter inference

NASA Astrophysics Data System (ADS)

Woodward, Simon James Roy; Wöhling, Thomas; Rode, Michael; Stenger, Roland

2017-09-01

The common practice of infrequent (e.g., monthly) stream water quality sampling for state of the environment monitoring may, when combined with high resolution stream flow data, provide sufficient information to accurately characterise the dominant nutrient transfer pathways and predict annual catchment yields. In the proposed approach, we use the spatially lumped catchment model StreamGEM to predict daily stream flow and nitrate concentration (mg L-1 NO3-N) in four contrasting mesoscale headwater catchments based on four years of daily rainfall, potential evapotranspiration, and stream flow measurements, and monthly or daily nitrate concentrations. Posterior model parameter distributions were estimated using the Markov Chain Monte Carlo sampling code DREAMZS and a log-likelihood function assuming heteroscedastic, t-distributed residuals. Despite high uncertainty in some model parameters, the flow and nitrate calibration data was well reproduced across all catchments (Nash-Sutcliffe efficiency against Log transformed data, NSL, in the range 0.62-0.83 for daily flow and 0.17-0.88 for nitrate concentration). The slight increase in the size of the residuals for a separate validation period was considered acceptable (NSL in the range 0.60-0.89 for daily flow and 0.10-0.74 for nitrate concentration, excluding one data set with limited validation data). Proportions of flow and nitrate discharge attributed to near-surface, fast seasonal groundwater and slow deeper groundwater were consistent with expectations based on catchment geology. The results for the Weida Stream in Thuringia, Germany, using monthly as opposed to daily nitrate data were, for all intents and purposes, identical, suggesting that four years of monthly nitrate sampling provides sufficient information for calibration of the StreamGEM model and prediction of catchment dynamics. This study highlights the remarkable effectiveness of process based, spatially lumped modelling with commonly available monthly stream sample data, to elucidate high resolution catchment function, when appropriate calibration methods are used that correctly handle the inherent uncertainties.

Digital flow model of the Chowan River estuary, North Carolina

USGS Publications Warehouse

Daniel, C.C.

1977-01-01

A one-dimensional deterministic flow model based on the continuity equation had been developed to provide estimates of daily flow past a number of points on the Chowan River estuary of northeast North Carolina. The digital model, programmed in Fortran IV, computes daily average discharge for nine sites; four of these represent inflow at the mouths of major tributaries, the five other sites are at stage stations along the estuary. Because flows within the Chowan River and the lower reaches of its tributaries are tidally affected, flows occur in both upstream and downstream directions. The period of record generated by the model extends from April 1, 1974, to March 31, 1976. During the two years of model operation the average discharge at Edenhouse near the mouth of the estuary was 5,830 cfs (cubic feet per second). Daily average flows during this period ranged from 55,900 cfs in the downstream direction on July 17, 1975, to 14,200 cfs in the upstream direction on November 30, 1974

Base-flow characteristics of streams in the Valley and Ridge, Blue Ridge, and Piedmont physiographic provinces of Virginia

USGS Publications Warehouse

Nelms, D.L.; Harlow, G.E.; Hayes, Donald C.

1995-01-01

Growth within the Valley and Ridge, Blue Ridge, and Piedmont Physiographic Provinces of Virginia has focussed concern about allocation of surface-water flow and increased demands on the ground-water resources. The purpose of this report is to (1) describe the base-flow characteristics of streams, (2) identify regional differences in these flow characteristics, and (3) describe, if possible, the potential surface-water and ground-water yields of basins on the basis of the base-flow character- istics. Base-flow characteristics are presented for streams in the Valley and Ridge, Blue Ridge, and Piedmont Physiographic Provinces of Virginia. The provinces are separated into five regions: (1) Valley and Ridge, (2) Blue Ridge, (3) Piedmont/Blue Ridge transition, (4) Piedmont northern, and (5) Piedmont southern. Different flow statistics, which represent streamflows predominantly comprised of base flow, were determined for 217 continuous-record streamflow-gaging stations from historical mean daily discharge and for 192 partial-record streamflow-gaging stations by means of correlation of discharge measurements. Variability of base flow is represented by a duration ratio developed during this investigation. Effective recharge rates were also calculated. Median values for the different flow statistics range from 0.05 cubic foot per second per square mile for the 90-percent discharge on the streamflow-duration curve to 0.61 cubic foot per second per square mile for mean base flow. An excellent estimator of mean base flow for the Piedmont/Blue Ridge transition region and Piedmont southern region is the 50-percent discharge on the streamflow-duration curve, but tends to under- estimate mean base flow for the remaining regions. The base-flow variability index ranges from 0.07 to 2.27, with a median value of 0.55. Effective recharge rates range from 0.07 to 33.07 inches per year, with a median value of 8.32 inches per year. Differences in the base-flow characteristics exist between regions. The median discharges for the Valley and Ridge, Blue Ridge, and Piedmont/Blue Ridge transition regions are higher than those for the Piedmont regions. Results from statistical analysis indicate that the regions can be ranked in terms of base-flow characteristics from highest to lowest as follows: (1) Piedmont/Blue Ridge transition, (2) Valley and Ridge and Blue Ridge, (3) Piedmont southern, and (4) Piedmont northern. The flow statistics are consistently higher and the values for base-flow variability are lower for basins within the Piedmont/Blue Ridge transition region relative to those from the other regions, whereas the basins within the Piedmont northern region show the opposite pattern. The group rankings of the base-flow characteristics were used to designate the potential surface-water yield for the regions. In addition, an approach developed for this investigation assigns a rank for potential surface- water yield to a basin according to the quartiles in which the values for the base-flow character- istics are located. Both procedures indicate that the Valley and Ridge, Blue Ridge, and Piedmont/Blue Ridge transition regions have moderate-to-high potential surface-water yield and the Piedmont regions have low-to-moderate potential surface- water yield. In order to indicate potential ground-water yield from base-flow characteristics, aquifer properties for 51 streamflow-gaging stations with continuous record of streamflow data were determined by methods that use streamflow records and basin characteristics. Areal diffusivity ranges from 17,100 to 88,400 feet squared per day, with a median value of 38,400 feet squared per day. Areal transmissivity ranges from 63 to 830 feet squared per day, with a median value of 270 feet squared per day. Storage coefficients, which were estimated by dividing areal transmissivity by areal diffusivity, range from approximately 0.001 to 0.019 (dimensionless), with a median value of 0.007. The median value for areal diffus

Response of sap flow to environmental factors in the headwater catchment of Miyun Reservoir in subhumid North China

NASA Astrophysics Data System (ADS)

Tie, Qiang; Hu, Hongchang; Tian, Fuqiang; Liu, Yaping; Xu, Ran

2015-04-01

Since the headwater catchment of Miyun Reservoir is the main drinking water conservation area of Beijing, its water cycle is of importance for the regional water resource. Transpiration is an important component of water cycle, which can be estimated by sap flow. In this study, the dynamics of sap flow and its response to environmental factors and relationship with leaf area index (LAI) were analyzed. The field study was conducted in the Xitaizi Experimental Catchment, located in the headwater catchment of Miyun Reservoir in subhumid North China. The Aspen (Populus davidiana) and Epinette (Larix gmelinii) are the two dominant tree species. Sap flow in 15 Aspen (Populus davidiana) trees was monitored using thermal dissipation probes (TDP) during the growing season of 2013 and 2014, and sap flow in another 3 Epinette (Larix gmelinii) trees was also monitored during September and October in 2014 for comparative analysis. Physiological and biometric parameters of the selected trees and the environmental factors, including meteorological variables, soil moisture content and groundwater table depth were measured. Vapor pressure deficit (VPD), variable of transpiration (VT) and reference crop evapotranspiration (ET0) were calculated using the measured environmental factors. The LAI, which is used to characterize phenophase, was calculated using the Moderate Resolution Imaging Spectroradiometer (MODIS) LAI product (MCD15A3). Correlation analysis for daily sap flow and air temperature, relative humidity, precipitation, wind speed, solar radiation, VPD, VT and ET0 under different soil moisture and groundwater table depth conditions was performed. Diurnal course and hysteresis of sap flow were analyzed as a function of air temperature, solar radiation, VPD and VT on the typical sunny, cloudy and rainy days under different soil moisture conditions. Correlation analysis between daily sap flow and LAI showed that LAI and phenophase significantly influence sap flow and restrict the maximum value of sap flow. The sap flow and its response to environmental factors were compared between Aspen and Epinette. The result could make contributions to improve empirical transpiration modeling for efficient water resource management in the headwater catchment of subhumid region.

Estimation of future flow regime for a spatially varied Himalayan watershed using improved multi-site calibration method of SWAT model.

NASA Astrophysics Data System (ADS)

Pradhanang, S. M.; Hasan, M. A.; Booth, P.; Fallatah, O.

2016-12-01

The monsoon and snow driven regime in the Himalayan region has received increasing attention in the recent decade regarding the effects of climate change on hydrologic regimes. Modeling streamflow in such spatially varied catchment requires proper calibration and validation in hydrologic modeling. While calibration and validation are time consuming and computationally intensive, an effective regionalized approach with multi-site information is crucial for flow estimation, especially in daily scale. In this study, we adopted a multi-site approach to calibration and validation of the Soil Water Assessment Tool (SWAT) model for the Karnali river catchment, which is characterized as being the most vulnerable catchment to climate change in the Himalayan region. APHRODITE's (Asian Precipitation - Highly-Resolved Observational Data Integration Towards Evaluation) daily gridded precipitation data, one of the accurate and reliable weather date over this region were utilized in this study. The model evaluation of the entire catchment divided into four sub-catchments, utilizing discharge records from 1963 to 2010. In previous studies, multi-site calibration used only a single set of calibration parameters for all sub-catchment of a large watershed. In this study, we introduced a technique that can incorporate different sets of calibration parameters for each sub-basin, which eventually ameliorate the flow of the whole watershed. Results show that the calibrated model with new method can capture almost identical pattern of flow over the region. The predicted daily streamflow matched the observed values, with a Nash-Sutcliffe coefficient of 0.73 during calibration and 0.71 during validation period. The method perfumed better than existing multi-site calibration methods. To assess the influence of continued climate change on hydrologic processes, we modified the weather inputs for the model using precipitation and temperature changes for two Representative Concentration Pathways (RCPs) scenarios, RCP 4.5 and 8.5. Climate simulation for RCP scenarios were conducted from 1981-2100, where 1981-2005 was considered as baseline and 2006-2100 was considered as the future projection. The result shows that probability of flooding will eventually increase in future years due to increased flow in both scenarios.

Influence of peak flow changes on the macroinvertebrate drift downstream of a Brazilian hydroelectric dam.

PubMed

Castro, D M P; Hughes, R M; Callisto, M

2013-11-01

Successive daily peak flows from hydropower plants can disrupt aquatic ecosystems and alter the composition and structure of macroinvertebrates downstream. We evaluated the influence of peak flow changes on macroinvertebrate drift downstream of a hydroelectric plant as a basis for determining ecological flows that might reduce the disturbance of aquatic biota. The aim of this study was to assess the influence of flow fluctuations on the seasonal and daily drift patterns of macroinvertebrates. We collected macroinvertebrates during fixed flow rates (323 m3.s-1 in the wet season and 111 m3.s-1 in the dry season) and when peak flows fluctuated (378 to 481 m3.s-1 in the wet season, and 109 to 173 m3.s-1 in the dry season) in 2010. We collected 31,924 organisms belonging to 46 taxa in the four sampling periods. Taxonomic composition and densities of drifting invertebrates differed between fixed and fluctuating flows, in both wet and dry seasons, but family richness varied insignificantly. We conclude that macroinvertebrate assemblages downstream of dams are influenced by daily peak flow fluctuations. When making environmental flow decisions for dams, it would be wise to consider drifting macroinvertebrates because they reflect ecological changes in downstream biological assemblages.

Relation Between Flow and Dissolved Oxygen in the Roanoke River Between Roanoke Rapids and Jamesville, North Carolina, 1998-2005

USGS Publications Warehouse

Wehmeyer, Loren L.; Bales, Jerad D.

2009-01-01

Understanding the relation between dam release characteristics and downstream water quality in the lower Roanoke River, North Carolina, is important for natural-resource management and ecosystem protection. Data from four raingages, four water-quality monitoring sites, and one streamflow-measurement site were used to identify statistical relations and discernible quantitative or qualitative patterns linking Roanoke River instream dissolved-oxygen (DO) levels to releases at Roanoke Rapids Dam for the period 1998-2005. The time-series DO data, complicated by the occurrence of major hurricanes in the short period of hourly DO data collection at the dam, present a mixed picture of the effects of hydropower peaking (a technique used by hydropower dam operators to produce electricity when consumption is high by passing a large volume of water through the dam turbines, which dramatically increases the volume of flow below the dam) on downstream DO. Other than in 2003 when dissolved-oxygen concentrations in the Roanoke River were likely affected by runoff from Hurricane Isabel rains, there were not consistent, statistically significant differences detected in the annual medians of hourly and(or) daily DO values during peaking versus nonpeaking periods. Along the Roanoke River, downstream of Roanoke Rapids Dam at Oak City, North Carolina, using a 95-percent confidence interval, the median value of the May-November daily mean DO concentrations for each year was lower during peaking periods for 2 years, higher for 2 years, and not significantly different for 4 years. Downstream at Jamesville, North Carolina, also using a 95-percent confidence interval, the median value of the annual May-November daily mean DO concentrations during hydropower peaking was lower for 4 years, higher for 2 years, and not significantly different for 2 years. In summary, the effect of hydropower peaking on downstream DO was inconsistent. Conversely, large precipitation events downstream from the dam resulted in consistent, statistically significant decreases in DO in the mainstem of the Roanoke River at Oak City and Jamesville.

User's manual for computer program BASEPLOT

USGS Publications Warehouse

Sanders, Curtis L.

2002-01-01

The checking and reviewing of daily records of streamflow within the U.S. Geological Survey is traditionally accomplished by hand-plotting and mentally collating tables of data. The process is time consuming, difficult to standardize, and subject to errors in computation, data entry, and logic. In addition, the presentation of flow data on the internet requires more timely and accurate computation of daily flow records. BASEPLOT was developed for checking and review of primary streamflow records within the U.S. Geological Survey. Use of BASEPLOT enables users to (1) provide efficiencies during the record checking and review process, (2) improve quality control, (3) achieve uniformity of checking and review techniques of simple stage-discharge relations, and (4) provide a tool for teaching streamflow computation techniques. The BASEPLOT program produces tables of quality control checks and produces plots of rating curves and discharge measurements; variable shift (V-shift) diagrams; and V-shifts converted to stage-discharge plots, using data stored in the U.S. Geological Survey Automatic Data Processing System database. In addition, the program plots unit-value hydrographs that show unit-value stages, shifts, and datum corrections; input shifts, datum corrections, and effective dates; discharge measurements; effective dates for rating tables; and numeric quality control checks. Checklist/tutorial forms are provided for reviewers to ensure completeness of review and standardize the review process. The program was written for the U.S. Geological Survey SUN computer using the Statistical Analysis System (SAS) software produced by SAS Institute, Incorporated.

How would peak rainfall intensity affect runoff predictions using conceptual water balance models?

NASA Astrophysics Data System (ADS)

Yu, B.

2015-06-01

Most hydrological models use continuous daily precipitation and potential evapotranspiration for streamflow estimation. With the projected increase in mean surface temperature, hydrological processes are set to intensify irrespective of the underlying changes to the mean precipitation. The effect of an increase in rainfall intensity on the long-term water balance is, however, not adequately accounted for in the commonly used hydrological models. This study follows from a previous comparative analysis of a non-stationary daily series of stream flow of a forested watershed (River Rimbaud) in the French Alps (area = 1.478 km2) (1966-2006). Non-stationarity in the recorded stream flow occurred as a result of a severe wild fire in 1990. Two daily models (AWBM and SimHyd) were initially calibrated for each of three distinct phases in relation to the well documented land disturbance. At the daily and monthly time scales, both models performed satisfactorily with the Nash-Sutcliffe coefficient of efficiency (NSE) varying from 0.77 to 0.92. When aggregated to the annual time scale, both models underestimated the flow by about 22% with a reduced NSE at about 0.71. Exploratory data analysis was undertaken to relate daily peak hourly rainfall intensity to the discrepancy between the observed and modelled daily runoff amount. Preliminary results show that the effect of peak hourly rainfall intensity on runoff prediction is insignificant, and model performance is unlikely to improve when peak daily precipitation is included. Trend analysis indicated that the large decrease of precipitation when daily precipitation amount exceeded 10-20 mm may have contributed greatly to the decrease in stream flow of this forested watershed.

Implications of flood pulse restoration for Populus regeneration on the upper Missouri River

USGS Publications Warehouse

Bovee, Ken D.; Scott, Michael L.

2002-01-01

We developed a mass balance flow model to reconstruct unregulated daily peak flows in the National Wild and Scenic reach of the Missouri River, Montana. Results indicated that although the observed frequency of large peak flows has not changed in the post-dam period, their magnitude has been reduced from 40 to 50% as a consequence of flow regulation. Reductions in the magnitude of these flows should reduce the expected frequency of large flood-pulses over a longer time-scale. Results of a two-dimensional hydraulic model indicated that limited cottonwood (Populus deltoides subsp. Monilifera) recruitment occurs at relatively small peak discharges, but to maximize establishment of cottonwoods in the Wild and Scenic reach, a threshold of 1850 m3/s would be necessary at the Virgelle gauge. Floods of this magnitude or greater lead to establishment of cottonwood seedlings above the zone of frequent ice-drive disturbance. Restoring the frequency, magnitude, duration and timing of these flood pulses would benefit important natural resource values including riparian cottonwood forests and native fish species in the upper Missouri River basin. However, efforts to naturalize flow must be made in the context of a water management system that was authorized and constructed for the primary purposes of flood control, power generation and irrigation. Using the synthesized flow model and flood damage curves, we examined six scenarios for delivering flows ≥1850 m3/s to the Wild and Scenic reach. Whereas some scenarios appeared to be politically and economically infeasible, our analysis suggested that there is enough operational flexibility in the system to restore more natural flood pulses without greatly compromising other values.

Assessment of flow regime alterations over a spectrum of temporal scales using wavelet-based approaches

NASA Astrophysics Data System (ADS)

Wu, Fu-Chun; Chang, Ching-Fu; Shiau, Jenq-Tzong

2015-05-01

The full range of natural flow regime is essential for sustaining the riverine ecosystems and biodiversity, yet there are still limited tools available for assessment of flow regime alterations over a spectrum of temporal scales. Wavelet analysis has proven useful for detecting hydrologic alterations at multiple scales via the wavelet power spectrum (WPS) series. The existing approach based on the global WPS (GWPS) ratio tends to be dominated by the rare high-power flows so that alterations of the more frequent low-power flows are often underrepresented. We devise a new approach based on individual deviations between WPS (DWPS) that are root-mean-squared to yield the global DWPS (GDWPS). We test these two approaches on the three reaches of the Feitsui Reservoir system (Taiwan) that are subjected to different classes of anthropogenic interventions. The GDWPS reveal unique features that are not detected with the GWPS ratios. We also segregate the effects of individual subflow components on the overall flow regime alterations using the subflow GDWPS. The results show that the daily hydropeaking waves below the reservoir not only intensified the flow oscillations at daily scale but most significantly eliminated subweekly flow variability. Alterations of flow regime were most severe below the diversion weir, where the residual hydropeaking resulted in a maximum impact at daily scale while the postdiversion null flows led to large hydrologic alterations over submonthly scales. The smallest impacts below the confluence reveal that the hydrologic alterations at scales longer than 2 days were substantially mitigated with the joining of the unregulated tributary flows, whereas the daily-scale hydrologic alteration was retained because of the hydropeaking inherited from the reservoir releases. The proposed DWPS approach unravels for the first time the details of flow regime alterations at these intermediate scales that are overridden by the low-frequency high-power flows when the long-term averaged GWPS are used.

Streamflow statistical summaries for Colorado streams through September 30, 1975; Volume 2, Colorado River basin

USGS Publications Warehouse

Petsch, Harold E.

1979-01-01

Statistical summaries of daily streamflow data for 189 stations west of the Continental Divide in Colorado are presented in this report. Duration tables, high-flow sequence tables, and low-flow sequence tables provide information about daily mean discharge. The mean, variance, standard deviation, skewness, and coefficient of variation are provided for monthly and annual flows. Percentages of average flow are provided for monthly flows and first-order serial-correlation coefficients are provided for annual flows. The text explain the nature and derivation of the data and illustrates applications of the tabulated information by examples. The data may be used by agencies and individuals engaged in water studies. (USGS)

Flow experience in the daily lives of older adults: an analysis of the interaction between flow, individual differences, serious leisure, location, and social context.

PubMed

Heo, Jinmoo; Lee, Youngkhill; Pedersen, Paul M; McCormick, Bryan P

2010-09-01

This study examined how serious leisure, individual differences, social context, and location contribute to older adults' experiences of flow - an intense psychological state - in their daily lives. The Experience Sampling Method was used with 19 older adults in a Midwestern city in the United States. Experience of flow was the outcome measure, and the data were analyzed using hierarchical linear modeling. Results indicated that location and employment status influenced the subjects' flow experience. Furthermore, the findings revealed that retirement was negatively related to experiencing flow, and there was a significant association between home and the flow experience. The results of this study enhance the understanding of flow experiences in the everyday lives of older adults.

On the impacts of computing daily temperatures as the average of the daily minimum and maximum temperatures

NASA Astrophysics Data System (ADS)

Villarini, Gabriele; Khouakhi, Abdou; Cunningham, Evan

2017-12-01

Daily temperature values are generally computed as the average of the daily minimum and maximum observations, which can lead to biases in the estimation of daily averaged values. This study examines the impacts of these biases on the calculation of climatology and trends in temperature extremes at 409 sites in North America with at least 25 years of complete hourly records. Our results show that the calculation of daily temperature based on the average of minimum and maximum daily readings leads to an overestimation of the daily values of 10+ % when focusing on extremes and values above (below) high (low) thresholds. Moreover, the effects of the data processing method on trend estimation are generally small, even though the use of the daily minimum and maximum readings reduces the power of trend detection ( 5-10% fewer trends detected in comparison with the reference data).

Streamflow characteristics and trends in New Jersey, water years 1897-2003

USGS Publications Warehouse

Watson, Kara M.; Reiser, Robert G.; Nieswand, Steven P.; Schopp, Robert D.

2005-01-01

Streamflow statistics were computed for 111 continuous-record streamflow-gaging stations with 20 or more years of continuous record and for 500 low-flow partial-record stations, including 66 gaging stations with less than 20 years of continuous record. Daily mean streamflow data from water year 1897 through water year 2001 were used for the computations at the gaging stations. (The water year is the 12-month period, October 1 through September 30, designated by the calendar year in which it ends). The characteristics presented for the long-term continuous-record stations are daily streamflow, harmonic mean flow, flow frequency, daily flow durations, trend analysis, and streamflow variability. Low-flow statistics for gaging stations with less than 20 years of record and for partial-record stations were estimated by correlating base-flow measurements with daily mean flows at long-term (more than 20 years) continuous-record stations. Instantaneous streamflow measurements through water year 2003 were used to estimate low-flow statistics at the partial-record stations. The characteristics presented for partial-record stations are mean annual flow; harmonic mean flow; and annual and winter low-flow frequency. The annual 1-, 7-, and 30-day low- and high-flow data sets were tested for trends. The results of trend tests for high flows indicate relations between upward trends for high flows and stream regulation, and high flows and development in the basin. The relation between development and low-flow trends does not appear to be as strong as for development and high-flow trends. Monthly, seasonal, and annual precipitation data for selected long-term meteorological stations also were tested for trends to analyze the effects of climate. A significant upward trend in precipitation in northern New Jersey, Climate Division 1 was identified. For Climate Division 2, no general increase in average precipitation was observed. Trend test results indicate that high flows at undeveloped, unregulated sites have not been affected by the increase in average precipitation. The ratio of instantaneous peak flow to 3-day mean flow, ratios of flow duration, ratios of high-flow/low-flow frequency, and coefficient of variation were used to define streamflow variability. Streamflow variability was significantly greater among the group of gaging stations located outside the Coastal Plain than among the group of gaging stations located in the Coastal Plain.

Solute kinetics with short-daily home hemodialysis using slow dialysate flow rate.

PubMed

Kohn, Orly F; Coe, Fredric L; Ing, Todd S

2010-01-01

"NxStage System One()" is increasingly used for daily home hemodialysis. The ultrapure dialysate volumes are typically between 15 L and 30 L per dialysis, substantially smaller than the volumes used in conventional dialysis. In this study, the impact of the use of low dialysate volumes on the removal rates of solutes of different molecular weights and volumes of distribution was evaluated. Serum measurements before and after dialysis and total dialysate collection were performed over 30 times in 5 functionally anephric patients undergoing short-daily home hemodialysis (6 d/wk) over the course of 8 to 16 months. Measured solutes included beta(2) microglobulin (beta(2)M), phosphorus, urea nitrogen, and potassium. The average spent dialysate volume (dialysate plus ultrafiltrate) was 25.4+/-4.7 L and the dialysis duration was 175+/-15 min. beta(2) microglobulin clearance of the polyethersulfone dialyzer averaged 53+/-14 mL/min. Total beta(2)M recovered in the dialysate was 106+/-42 mg per treatment (n=38). Predialysis serum beta(2)M levels remained stable over the observation period. Phosphorus removal averaged 694+/-343 mg per treatment with a mean predialysis serum phosphorus of 5.2+/-1.8 mg/dL (n=34). Standard Kt/V averaged 2.5+/-0.3 per week and correlated with the dialysate-based weekly Kt/V. Weekly beta(2)M, phosphorus, and urea nitrogen removal in patients dialyzing 6 d/wk with these relatively low dialysate volumes compared favorably with values published for thrice weekly conventional and with short-daily hemodialysis performed with machines using much higher dialysate flow rates. Results of the present study were achieved, however, with an average of 17.5 hours of dialysis per week.

A stochastic flow-capturing model to optimize the location of fast-charging stations with uncertain electric vehicle flows

DOE PAGES

Wu, Fei; Sioshansi, Ramteen

2017-05-04

Here, we develop a model to optimize the location of public fast charging stations for electric vehicles (EVs). A difficulty in planning the placement of charging stations is uncertainty in where EV charging demands appear. For this reason, we use a stochastic flow-capturing location model (SFCLM). A sample-average approximation method and an averaged two-replication procedure are used to solve the problem and estimate the solution quality. We demonstrate the use of the SFCLM using a Central-Ohio based case study. We find that most of the stations built are concentrated around the urban core of the region. As the number ofmore » stations built increases, some appear on the outskirts of the region to provide an extended charging network. We find that the sets of optimal charging station locations as a function of the number of stations built are approximately nested. We demonstrate the benefits of the charging-station network in terms of how many EVs are able to complete their daily trips by charging midday—six public charging stations allow at least 60% of EVs that would otherwise not be able to complete their daily tours without the stations to do so. We finally compare the SFCLM to a deterministic model, in which EV flows are set equal to their expected values. We show that if a limited number of charging stations are to be built, the SFCLM outperforms the deterministic model. As the number of stations to be built increases, the SFCLM and deterministic model select very similar station locations.« less

Comparison of HSPF and PRMS model simulated flows using different temporal and spatial scales in the Black Hills, South Dakota

USGS Publications Warehouse

Chalise, D. R.; Haj, Adel E.; Fontaine, T.A.

2018-01-01

The hydrological simulation program Fortran (HSPF) [Hydrological Simulation Program Fortran version 12.2 (Computer software). USEPA, Washington, DC] and the precipitation runoff modeling system (PRMS) [Precipitation Runoff Modeling System version 4.0 (Computer software). USGS, Reston, VA] models are semidistributed, deterministic hydrological tools for simulating the impacts of precipitation, land use, and climate on basin hydrology and streamflow. Both models have been applied independently to many watersheds across the United States. This paper reports the statistical results assessing various temporal (daily, monthly, and annual) and spatial (small versus large watershed) scale biases in HSPF and PRMS simulations using two watersheds in the Black Hills, South Dakota. The Nash-Sutcliffe efficiency (NSE), Pearson correlation coefficient (r">rr), and coefficient of determination (R2">R2R2) statistics for the daily, monthly, and annual flows were used to evaluate the models’ performance. Results from the HSPF models showed that the HSPF consistently simulated the annual flows for both large and small basins better than the monthly and daily flows, and the simulated flows for the small watershed better than flows for the large watershed. In comparison, the PRMS model results show that the PRMS simulated the monthly flows for both the large and small watersheds better than the daily and annual flows, and the range of statistical error in the PRMS models was greater than that in the HSPF models. Moreover, it can be concluded that the statistical error in the HSPF and the PRMSdaily, monthly, and annual flow estimates for watersheds in the Black Hills was influenced by both temporal and spatial scale variability.

Model for economic evaluation of high energy gas fracturing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Engi, D.

1984-05-01

The HEGF/NPV model has been developed and adapted for interactive microcomputer calculations of the economic consequences of reservoir stimulation by high energy gas fracturing (HEGF) in naturally fractured formations. This model makes use of three individual models: a model of the stimulated reservoir, a model of the gas flow in this reservoir, and a model of the discounted expected net cash flow (net present value, or NPV) associated with the enhanced gas production. Nominal values of the input parameters, based on observed data and reasonable estimates, are used to calculate the initial expected increase in the average daily rate ofmore » production resulting from the Meigs County HEGF stimulation experiment. Agreement with the observed initial increase in rate is good. On the basis of this calculation, production from the Meigs County Well is not expected to be profitable, but the HEGF/NPV model probably provides conservative results. Furthermore, analyses of the sensitivity of the expected NPV to variations in the values of certain reservoir parameters suggest that the use of HEGF stimulation in somewhat more favorable formations is potentially profitable. 6 references, 4 figures, 3 tables.« less

Daily dynamics of emerging pollutants in a sewer network (région Centre, France)

NASA Astrophysics Data System (ADS)

Thiebault, Thomas; Réty, Maxime; Jacob, Jérémy; Destandau, Emilie; Fougère, Laetitia; Morio, Cédric

2017-04-01

As any catchment, cities are characterized by important flux of various materials. The specificity of urban socio-ecosystems lies in the nature of these materials that mainly result from human activities or are man-made. An important issue concerns emerging pollutants for which an understanding of their temporal dynamics is crucial to better forecast flux and adapt remediation treatments before waters are released in the environment. This study aims at better understanding the socio-economic drivers of emerging pollutants temporal dynamics by monitoring, on a daily basis during 85 consecutive days, a series of fifty illicit drugs and pharmaceuticals as well as their metabolites in a sewer network that collects wastewater from 90,000 inhabitants and upstream a wastewater plant. Flow-enslaved composite samples were automatically collected over 24h, then filtered, and target compounds were concentrated by solid-phase extraction before quantitation by HPLC-MS. Concentrations were converted into mass loads per population equivalent by several corrections (i) the flow, (ii) the solid/liquid partition and the molar ratio between target residue and parent-compound (iii) the number of population-equivalent on the catchment and (iv) the excretion rate of target residue. The large dataset obtained, combined to a literature survey, allows us discussing several issues. (1) Calculated daily mass loads of pharmaceuticals are in agreement with literature data for comparable cities except for to anti-inflammatory drugs: ketoprofen that shows the highest values and ibuprofen that displays the lowest values. This would attest to local therapeutic preference that remains to be explained. Daily mass loads for illicit drugs are lower than those measured in more populated cities, except for tetrahydrocannabinol that exceeds the highest reported values. (2) Consumption estimates of pharmaceutical based on our approach are very close to theoretical values from the literature. Additionally, ratios of co-consumed antibiotics such as sulfamethoxazole and trimethoprim are constant over the study and afford similar estimates for their consumption. For evident reasons, this comparison between theoretical and calculated consumption could not be achieved for illicit drugs. (3) Distinction can clearly be made on the temporal pattern of consumptions. Some compounds (e.g. acetaminophen, atenolol) do not exhibit clear week/week-end pattern whereas it is clearly expressed for cocaine and ecstasy. For the first time, some week/week-end patterns were also found for some pharmaceuticals such as metoprolol. Lower values noticed during week-end days could result from the mobility of the population in the catchment. Our study reveals that monitoring of pharmaceuticals and illicit drugs in wastewaters can bring significant information on the evolution of consumption practices in urban areas. Additional work in engaged to evaluate temporal trends on shorter (hour, minute) and longer (season, year) timescales. Applying this approach to a larger set of cities could reveal useful for developing decision tools for stakeholders and health agencies.

Streamflow statistical summaries for Colorado streams through September 30, 1975: Volume 1: Missouri River, Arkansas River, and Rio Grande Basins

USGS Publications Warehouse

Petsch, Harold E.

1979-01-01

Statistical summaries of daily streamflow data for 246 stations east of the Continental Divide in Colorado and adjacent States are presented in this report. Duration tables, high-flow sequence tables, and low-flow sequence tables provide information about daily mean discharge. The mean, variance, standard deviation, skewness, and coefficient of variation are provided for monthly and annual flows. Percentages of average flow are provided for monthly flows and first-order serial-correlation coefficients are provided for annual flows. The text explains the nature and derivation of the data and illustrates applications of the tabulated information by examples. The data may be used by agencies and individuals engaged in water studies. (USGS)

Assessing the Impact of Climate Change on Stream Temperatures in the Methow River Basin, Washington

NASA Astrophysics Data System (ADS)

Gangopadhyay, S.; Caldwell, R. J.; Lai, Y.; Bountry, J.

2011-12-01

The Methow River in Washington offers prime spawning habitat for salmon and other cold-water fishes. During the summer months, low streamflows on the Methow result in cutoff side channels that limit the habitat available to these fishes. Future climate scenarios of increasing air temperature and decreasing precipitation suggest the potential for increasing loss of habitat and fish mortality as stream temperatures rise in response to lower flows and additional heating. To assess the impacts of climate change on stream temperature in the Methow River, the US Bureau of Reclamation is developing an hourly time-step, two-dimensional hydraulic model of the confluence of the Methow and Chewuch Rivers above Winthrop. The model will be coupled with a physical stream temperature model to generate spatial representations of stream conditions conducive for fish habitat. In this study, we develop a statistical framework for generating stream temperature time series from global climate model (GCM) and hydrologic model outputs. Regional observations of stream temperature and hydrometeorological conditions are used to develop statistical models of daily mean stream temperature for the Methow River at Winthrop, WA. Temperature and precipitation projections from 10 global climate models (GCMs) are coupled with the streamflow generated using the University of Washington Variable Infiltration Capacity model. The projections serve as input to the statistical models to generate daily time series of mean daily stream temperature. Since the output from the GCM, VIC, and statistical models offer only daily data, a k-nearest neighbor (k-nn) resampling technique is employed to select appropriate proportion vectors for disaggregating the Winthrop daily flow and temperature to an upstream location on each of the rivers above the confluence. Hourly proportion vectors are then used to disaggregate the daily flow and temperature to hourly values to be used in the hydraulic model. Historical meteorological variables are also selected using the k-nn method. We present the statistical modeling framework using Generalized Linear Models (GLMs), along with diagnostics and measurements of skill. We will also provide a comparison of the stream temperature projections from the future years of 2020, 2040, and 2080 and discuss the potential implications on fish habitat in the Methow River. Future integration of the hourly climate scenarios in the hydraulic model will provide the ability to assess the spatial extent of habitat impacts and allow the USBR to evaluate the effectiveness of various river restoration projects in maintaining or improving habitat in a changing climate.

Runoff characteristics of California streams

USGS Publications Warehouse

Rantz, S.E.

1972-01-01

California streams exhibit a wide range of runoff characteristics that are related to the climatologic, topographic, and geologic characteristics of the basins they drain. The annual volume of runoff of a stream, expressed in inches, may be large or small, and daily discharge rates may be highly variable or relatively steady. The bulk of the annual runoff may be storm runoff, or snowmelt runoff, or a combination of both. The streamflow may be ephemeral, intermittent, or perennial; if perennial, base flow may be well sustained or poorly sustained. In this report the various runoff characteristics are identified by numerical index values. They are shown to be related generally to mean annual precipitation, altitude, latitude, and location with respect to the 11 geomorphic provinces in the California Region. With respect to mean annual precipitation on the watershed, streamflow is generally (1) ephemeral if the mean annual precipitation is less than 10 inches, (2) intermittent if the mean annual precipitation is between 10 and 40 inches, and (3) perennial if the mean annual precipitation is more than 40 inches. Departures from those generalizations are associated with (a) the areal variation of such geologic factors as the infiltration and storage capacities of the rocks underlying the watersheds, and (b) the areal variation of evapotranspiration loss as influenced by varying conditions of climate, soil, vegetal cover, and geologic structure. Latitude and altitude determine the proportion of the winter precipitation that will be stored for subsequent runoff in the late spring and summer. In general, if a watershed has at least 30 percent of its area above the normal altitude of the snowline on April 1, it will have significant snowmelt runoff. Snowmelt runoff in California is said to be significant if at least 30 percent of the annual runoff occurs during the 4 months, April through July. Storm runoff is said to be predominant if at least 65 percent of the annual runoff occurs during the 6 months, October through March. Base flow (ground-water outflow), as a factor in the regimen of streamflow, is qualified on the basis of the percentage of the mean annual runoff that occurs during the fair-weather months of August and September. If the sum of the August and September runoff exceeds 3.0 percent of the annual runoff, base flow is considered to be well sustained; if the percentage is between 1.5 and 3.0, base flow is considered to be fairly well sustained; if the percentage is less than 1.5, baseflow is considered to be poorly sustained. The characteristics of duration curves of daily streamflow are influenced by the regimen of runoff. The distribution of daily flow is skewed for all streams, but it is more skewed for streams whose flow is predominantly storm runoff than for streams that carry significantly large quantities of snowmelt. Least skewed is the distribution for streams that carry large quantities of base flow. Either of two characteristics of the duration curve may be used as an index of skew--the percentage of time that the mean discharge is equaled or exceeded or the ratio of the median discharge to the mean discharge. As for variability of daily discharge, the variability of storm-runoff streams is greater than that of snowmelt streams, and the lowest values of variability are associated with streams that carry large quantities of base flow. The index of variability used in this study was the ratio of the discharge equaled or exceeded 10 percent of the time to the discharge equaled or exceeded 90 percent of the time. The identification of streamflow characteristics by numerical index figures greatly facilitates comparison of the diverse runoff regimens of streams in the California Region.

Recharge Area, Base-Flow and Quick-Flow Discharge Rates and Ages, and General Water Quality of Big Spring in Carter County, Missouri, 2000-04

USGS Publications Warehouse

Imes, Jeffrey L.; Plummer, Niel; Kleeschulte, Michael J.; Schumacher, John G.

2007-01-01

Exploration for lead deposits has occurred in a mature karst area of southeast Missouri that is highly valued for its scenic beauty and recreational opportunities. The area contains the two largest springs in Missouri (Big Spring and Greer Spring), both of which flow into federally designated scenic rivers. Concerns about potential mining effects on the area ground water and aquatic biota prompted an investigation of Big Spring. Water-level measurements made during 2000 helped define the recharge area of Big Spring, Greer Spring, Mammoth Spring, and Boze Mill Spring. The data infer two distinct potentiometric surfaces. The shallow potentiometric surface, where the depth-to-water is less than about 250 feet, tends to mimic topographic features and is strongly controlled by streams. The deep potentiometric surface, where the depth-to-water is greater than about 250 feet represents ground-water hydraulic heads within the more mature karst areas. A highly permeable zone extends about 20 mile west of Big Spring toward the upper Hurricane Creek Basin. Deeper flowing water in the Big Spring recharge area is directed toward this permeable zone. The estimated sizes of the spring recharge areas are 426 square miles for Big Spring, 352 square miles for Greer Spring, 290 square miles for Mammoth Spring, and 54 square miles for Boze Mill Spring. A discharge accumulation curve using Big Spring daily mean discharge data shows no substantial change in the discharge pattern of Big Spring during the period of record (water years 1922 through 2004). The extended periods when the spring flow deviated from the trend line can be attributed to prolonged departures from normal precipitation. The maximum possible instantaneous flow from Big Spring has not been adequately defined because of backwater effects from the Current River during high-flow conditions. Physical constraints within the spring conduit system may restrict its maximum flow. The largest discharge measured at Big Spring during the period of record (water years 1922 through 2004) was 1,170 cubic feet per second on December 7, 1982. The daily mean water temperature of Big Spring was monitored during water years 2001 through 2004 and showed little variability, ranging from 13 to 15? C (degree Celsius). Water temperatures generally vary less than 1? C throughout the year. The warmest temperatures occur during October and November and decrease until April, indicating Big Spring water temperature does show a slight seasonal variation. The use of the traditional hydrograph separation program HYSEP to determine the base flow and quick flow or runoff components at Big Spring failed to yield base-flow and quick-flow discharge curves that matched observations of spring characteristics. Big Spring discharge data were used in combination with specific conductance data to develop an improved hydrograph separation method for the spring. The estimated annual mean quick flow ranged from 15 to 48 cubic feet per second for the HYSEP analysis and ranged from 26 to 154 cubic feet per second for the discharge and specific conductance method for water years 2001 to 2004. Using the discharge and specific conductance method, the estimated base-flow component rises abruptly as the spring hydrograph rises, attains a peak value on the same day as the discharge peak, and then declines abruptly from its peak value. Several days later, base flow begins to increase again at an approximately linear trend, coinciding with the time at which the percentage of quick flow has reached a maximum after each recharge-induced discharge peak. The interval between the discharge peak and the peak in percentage quick flow ranges from 8 to 11 days for seven hydrograph peaks, consistent with quick-flow traveltime estimates by dye-trace tests from the mature karst Hurricane Creek Basin in the central part of the recharge area. Concentrations of environmental tracers chlorofluorocarbons (CFCs: CFC-11, CFC-12, CFC-113)

Validation and Development of the GPCP Experimental One-Degree Daily (1DD) Global Precipitation Product

NASA Technical Reports Server (NTRS)

Huffman, George J.; Adler, Robert F.; Bolvin, David T.; Einaud, Franco (Technical Monitor)

2000-01-01

The One-Degree Daily (1DD) precipitation dataset has been developed for the Global Precipitation Climatology Project (GPCP) and is currently in beta test preparatory to release as an official GPCP product. The 1DD provides a globally-complete, observation-only estimate of precipitation on a daily 1 deg. x 1 deg. grid for the period 1997 through early 2000 (by the time of the conference). In the latitude band 40N-40S the 1DD uses the Threshold-Matched Precipitation Index (TMPI), a GPI-like IR product with the pixel-level T(sub b) threshold and (single) conditional rain rate determined locally for each month by the frequency of precipitation in the GPROF SSM/I product and by, the precipitation amount in the GPCP monthly satellite-gauge (SG) combination. Outside 40N-40S the 1DD uses a scaled TOVS precipitation estimate that has month-by-month adjustments based on the TMPI and the SG. Early validation results are encouraging. The 1DD shows relatively large scatter about the daily validation values in individual grid boxes, as expected for a technique that depends on cloud-sensing schemes such as the TMPI and TOVS. On the other hand, the time series of 1DD shows good correlation with validation in individual boxes. For example, the 1997-1998 time series of 1DD and Oklahoma Mesonet values in a grid box in northeastern Oklahoma have the correlation coefficient = 0.73. Looking more carefully at these two time series, the number of raining days for the 1DD is within 7% of the Mesonet value, while the distribution of daily rain values is very similar. Other tests indicate that area- or time-averaging improve the error characteristics, making the data set highly attractive to users interested in stream flow, short-term regional climatology, and model comparisons. The second generation of the 1DD product is currently under development; it is designed to directly incorporate TRMM and other high-quality precipitation estimates. These data are generally sparse because they are observed by low-orbit satellites, so a fair amount of work must be devoted to analyzing the effect of data boundaries. This work is laying, the groundwork for effective use of the NASA Global Precipitation Mission, which will have full Global coverage by low-orbit passive microwave satellites every three hours.

The U.S. Geological Survey Peak-Flow File Data Verification Project, 2008–16

USGS Publications Warehouse

Ryberg, Karen R.; Goree, Burl B.; Williams-Sether, Tara; Mason, Robert R.

2017-11-21

Annual peak streamflow (peak flow) at a streamgage is defined as the maximum instantaneous flow in a water year. A water year begins on October 1 and continues through September 30 of the following year; for example, water year 2015 extends from October 1, 2014, through September 30, 2015. The accuracy, characterization, and completeness of the peak streamflow data are critical in determining flood-frequency estimates that are used daily to design water and transportation infrastructure, delineate flood-plain boundaries, and regulate development and utilization of lands throughout the United States and are essential to understanding the implications of climate and land-use change on flooding and high-flow conditions.As of November 14, 2016, peak-flow data existed for 27,240 unique streamgages in the United States and its territories. The data, collectively referred to as the “peak-flow file,” are available as part of the U.S. Geological Survey (USGS) public web interface, the National Water Information System, at https://nwis.waterdata.usgs.gov/usa/nwis/peak. Although the data have been routinely subjected to periodic review by the USGS Office of Surface Water and screening at the USGS Water Science Center level, these data were not reviewed in a national, systematic manner until 2008 when automated scripts were developed and applied to detect potential errors in peak-flow values and their associated dates, gage heights, and peak-flow qualification codes, as well as qualification codes associated with the gage heights. USGS scientists and hydrographers studied the resulting output, accessed basic records and field notes, and corrected observed errors or, more commonly, confirmed existing data as correct.This report summarizes the changes in peak-flow file data at a national level, illustrates their nature and causation, and identifies the streamgages affected by these changes. Specifically, the peak-flow data were compared for streamgages with peak flow measured as of November 19, 2008 (before the automated scripts were widely applied) and on November 14, 2016 (after several rounds of corrections). There were 659,332 peak-flow values in the 2008 dataset and 731,965 peak-flow values in the 2016 dataset. When compared to the 2016 dataset, 5,179 (0.79 percent) peak-flow values had changed; 36,506 (5.54 percent) of the peak-flow qualification codes had changed; 1,938 (0.29 percent) peak-flow dates had changed; 18,599 (2.82 percent) of the peak-flow gage heights had changed; and 20,683 (3.14 percent) of the gage-height qualification codes had changed—most as a direct result of the peak-flow file data verification effort led by USGS personnel. The various types of changes are summarized and mapped in this report. In addition to this report, a corresponding USGS data release is provided to identify changes in peak flows at individual streamgages. The data release and the procedures to access the data release are described in this report.

Analysis of low flows and selected methods for estimating low-flow characteristics at partial-record and ungaged stream sites in western Washington

USGS Publications Warehouse

Curran, Christopher A.; Eng, Ken; Konrad, Christopher P.

2012-01-01

Regional low-flow regression models for estimating Q7,10 at ungaged stream sites are developed from the records of daily discharge at 65 continuous gaging stations (including 22 discontinued gaging stations) for the purpose of evaluating explanatory variables. By incorporating the base-flow recession time constant τ as an explanatory variable in the regression model, the root-mean square error for estimating Q7,10 at ungaged sites can be lowered to 72 percent (for known values of τ), which is 42 percent less than if only basin area and mean annual precipitation are used as explanatory variables. If partial-record sites are included in the regression data set, τ must be estimated from pairs of discharge measurements made during continuous periods of declining low flows. Eight measurement pairs are optimal for estimating τ at partial-record sites, and result in a lowering of the root-mean square error by 25 percent. A low-flow survey strategy that includes paired measurements at partial-record sites requires additional effort and planning beyond a standard strategy, but could be used to enhance regional estimates of τ and potentially reduce the error of regional regression models for estimating low-flow characteristics at ungaged sites.

Viscosity changes of riparian water controls diurnal fluctuations of stream-flow and DOC concentration

NASA Astrophysics Data System (ADS)

Schwab, Michael; Klaus, Julian; Pfister, Laurent; Weiler, Markus

2015-04-01

Diurnal fluctuations in stream-flow are commonly explained as being triggered by the daily evapotranspiration cycle in the riparian zone, leading to stream flow minima in the afternoon. While this trigger effect must necessarily be constrained by the extent of the growing season of vegetation, we here show evidence of daily stream flow maxima in the afternoon in a small headwater stream during the dormant season. We hypothesize that the afternoon maxima in stream flow are induced by viscosity changes of riparian water that is caused by diurnal temperature variations of the near surface groundwater in the riparian zone. The patterns were observed in the Weierbach headwater catchment in Luxembourg. The catchment is covering an area of 0.45 km2, is entirely covered by forest and is dominated by a schistous substratum. DOC concentration at the outlet of the catchment was measured with the field deployable UV-Vis spectrometer spectro::lyser (scan Messtechnik GmbH) with a high frequency of 15 minutes over several months. Discharge was measured with an ISCO 4120 Flow Logger. During the growing season, stream flow shows a frequently observed diurnal pattern with discharge minima in the afternoon. During the dormant season, a long dry period with daily air temperature amplitudes of around 10 ° C occurred in March and April 2014, with discharge maxima in the afternoon. The daily air temperature amplitude led to diurnal variations in the water temperature of the upper 10 cm of the riparian zone. Higher riparian water temperatures cause a decrease in water viscosity and according to the Hagen-Poiseuille equation, the volumetric flow rate is inversely proportional to viscosity. Based on the Hagen-Poiseuille equation and the viscosity changes of water, we calculated higher flow rates of near surface groundwater through the riparian zone into the stream in the afternoon which explains the stream flow maxima in the afternoon. With the start of the growing season, the viscosity induced diurnal effect is overlain by the stronger influence of evapotranspiration. Diurnal DOC fluctuations show daily maxima in the afternoon. While daily variations in DOC concentrations are often explained by faster in-stream biogeochemical processes during daylight, we here propose that the viscosity effect in the riparian zone could explain the afternoon peaks in DOC concentrations. Our records show that daily water temperature variations and therefore viscosity changes only occur in the near surface parts of the riparian zone, where the DOC concentrations are higher than in deeper parts of the riparian zone. We calculated, that the viscosity induced higher flow rates from the near surface parts of the riparian zone can explain the DOC concentration maxima in the afternoon. As the viscosity effect does not disappear during the growing season but is just smaller than the evapotranspiration effect, the DOC concentration pattern is not changing between the dormant and growing seasons. The different controls of diurnal fluctuations of stream-flow and water quality concentrations need to be carefully considered in order to better understand the different patterns in catchment hydrology.

Estimates of natural streamflow at two streamgages on the Esopus Creek, New York, water years 1932 to 2012

USGS Publications Warehouse

Burns, Douglas A.; Gazoorian, Christopher L.

2015-01-01

Natural discharge at the Mount Marion streamgage was estimated by summing the natural discharge estimated for the Coldbrook streamgage and the discharge estimated for the intervening basin area through application of the New York Streamflow Estimation Tool, recently developed for estimating unaltered streamflow at ungaged locations in the State. Estimates of natural daily discharge at the Mount Marion streamgage were about three times greater than gaged daily discharge throughout the moderate- to low-flow range from October 1, 1970, to September 30, 2012, the period of record for full water years at this streamgage. The relative difference between the two discharge time series declined as flow increased beyond the moderate range, but gaged daily discharge was still 25 to 43 percent less than estimated natural daily discharge for the high-flow metrics calculated in this analysis, and the mean relative difference was 43 percent for the annual 1-day maximum discharge. Overall, these estimates of natural discharge reflect the absence of effects of the Shandaken Tunnel and Ashokan Reservoir on flows in the Esopus Creek over broad time frames. However, caution is warranted if one is attempting to apply the natural estimates at short time scales because the regression prediction intervals indicate that uncertainty at a daily time step ranges from about 40 to 80 percent.

Improving estuary models by reducing uncertainties associated with river flows

NASA Astrophysics Data System (ADS)

Robins, Peter E.; Lewis, Matt J.; Freer, Jim; Cooper, David M.; Skinner, Christopher J.; Coulthard, Tom J.

2018-07-01

To mitigate against future changes to estuaries such as water quality, catchment and estuary models can be coupled to simulate the transport of harmful pathogenic viruses, pollutants and nutrients from their terrestrial sources, through the estuary and to the coast. To predict future changes to estuaries, daily mean river flow projections are typically used. We show that this approach cannot resolve higher frequency discharge events that have large impacts to estuarine dilution, contamination and recovery for two contrasting estuaries. We therefore characterise sub-daily scale flow variability and propagate this through an estuary model to provide robust estimates of impacts for the future. River flow data (35-year records at 15-min sampling) were used to characterise variabilities in storm hydrograph shapes and simulate the estuarine response. In particular, we modelled a fast-responding catchment-estuary system (Conwy, UK), where the natural variability in hydrograph shapes generated large variability in estuarine circulation that was not captured when using daily-averaged river forcing. In the extreme, the freshwater plume from a 'flash' flood (lasting <12 h) was underestimated by up to 100% - and the response to nutrient loading was underestimated further still. A model of a slower-responding system (Humber, UK), where hydrographs typically last 2-4 days, showed less variability in estuarine circulation and good approximation with daily-averaged flow forcing. Our result has implications for entire system impact modelling; when we determine future changes to estuaries, some systems will need higher resolution future river flow estimates.

COMT ValMet moderation of cannabis-induced psychosis: a momentary assessment study of 'switching on' hallucinations in the flow of daily life.

PubMed

Henquet, C; Rosa, A; Delespaul, P; Papiol, S; Fananás, L; van Os, J; Myin-Germeys, I

2009-02-01

A functional polymorphism in the catechol-o-methyltransferase gene (COMT Val(158)Met) may moderate the psychosis-inducing effects of cannabis. In order to extend this finding to dynamic effects in the flow of daily life, a momentary assessment study of psychotic symptoms in response to cannabis use was conducted. The experience sampling technique was used to collect data on cannabis use and occurrence of symptoms in daily life in patients with a psychotic disorder (n = 31) and healthy controls (n = 25). Carriers of the COMT Val(158)Met Val allele, but not subjects with the Met/Met genotype, showed an increase in hallucinations after cannabis exposure, conditional on prior evidence of psychometric psychosis liability. The findings confirm that in people with psychometric evidence of psychosis liability, COMT Val(158)Met genotype moderates the association between cannabis and psychotic phenomena in the flow of daily life.

Streamflow simulation studies of the Hillsborough, Alafia, and Anclote Rivers, west-central Florida

USGS Publications Warehouse

Turner, J.F.

1979-01-01

A modified version of the Georgia Tech Watershed Model was applied for the purpose of flow simulation in three large river basins of west-central Florida. Calibrations were evaluated by comparing the following synthesized and observed data: annual hydrographs for the 1959, 1960, 1973 and 1974 water years, flood hydrographs (maximum daily discharge and flood volume), and long-term annual flood-peak discharges (1950-72). Annual hydrographs, excluding the 1973 water year, were compared using average absolute error in annual runoff and daily flows and correlation coefficients of monthly and daily flows. Correlations coefficients for simulated and observed maximum daily discharges and flood volumes used for calibrating range from 0.91 to 0.98 and average standard errors of estimate range from 18 to 45 percent. Correlation coefficients for simulated and observed annual flood-peak discharges range from 0.60 to 0.74 and average standard errors of estimate range from 33 to 44 percent. (Woodard-USGS)

Assessing the skill of seasonal precipitation and streamflow forecasts in sixteen French catchments

NASA Astrophysics Data System (ADS)

Crochemore, Louise; Ramos, Maria-Helena; Pappenberger, Florian

2015-04-01

Meteorological centres make sustained efforts to provide seasonal forecasts that are increasingly skilful. Streamflow forecasting is one of the many applications than can benefit from these efforts. Seasonal flow forecasts generated using seasonal ensemble precipitation forecasts as input to a hydrological model can help to take anticipatory measures for water supply reservoir operation or drought risk management. The objective of the study is to assess the skill of seasonal precipitation and streamflow forecasts in France. First, we evaluated the skill of ECMWF SYS4 seasonal precipitation forecasts for streamflow forecasting in sixteen French catchments. Daily flow forecasts were produced using raw seasonal precipitation forecasts as input to the GR6J hydrological model. Ensemble forecasts are issued every month with 15 or 51 members according to the month of the year and evaluated for up to 90 days ahead. In a second step, we applied eight variants of bias correction approaches to the precipitation forecasts prior to generating the flow forecasts. The approaches were based on the linear scaling and the distribution mapping methods. The skill of the ensemble forecasts was assessed in accuracy (MAE), reliability (PIT Diagram) and overall performance (CRPS). The results show that, in most catchments, raw seasonal precipitation and streamflow forecasts are more skilful in terms of accuracy and overall performance than a reference prediction based on historic observed precipitation and watershed initial conditions at the time of forecast. Reliability is the only attribute that is not significantly improved. The skill of the forecasts is, in general, improved when applying bias correction. Two bias correction methods showed the best performance for the studied catchments: the simple linear scaling of monthly values and the empirical distribution mapping of daily values. L. Crochemore is funded by the Interreg IVB DROP Project (Benefit of governance in DROught adaPtation).

Hydrological alteration along the Missouri River Basin: A time series approach

USGS Publications Warehouse

Pegg, M.A.; Pierce, C.L.; Roy, A.

2003-01-01

Human alteration of large rivers is common-place, often resulting in significant changes in flow characteristics. We used a time series approach to examine daily mean flow data from locations throughout the main-stem Missouri River. Data from a pre-alteration period (1925-1948) were compared with a post-alteration period (1967-1996), with separate analyses conducted using either data from the entire year or restricted to the spring fish spawning period (1 April-30 June). Daily mean flows were significantly higher during the post-alteration period at all locations. Flow variability was markedly reduced during the post-alteration period as a probable result of flow regulation and climatological shifts. Daily mean flow during the spring fish spawning period was significantly lower during the post-alteration period at the most highly altered locations in the middle portion of the river, but unchanged at the least altered locations in the upper and lower portions of the river. Our data also corroborate other analyses, using alternate statistical approaches, that suggest similar changes to the Missouri River system. Our results suggest human alterations on the Missouri River, particularly in the middle portion most strongly affected by impoundments and channelization, have resulted in changes to the natural flow regime.

Flood Frequency Analysis For Partial Duration Series In Ganjiang River Basin

NASA Astrophysics Data System (ADS)

zhangli, Sun; xiufang, Zhu; yaozhong, Pan

2016-04-01

Accurate estimation of flood frequency is key to effective, nationwide flood damage abatement programs. The partial duration series (PDS) method is widely used in hydrologic studies because it considers all events above a certain threshold level as compared to the annual maximum series (AMS) method, which considers only the annual maximum value. However, the PDS has a drawback in that it is difficult to define the thresholds and maintain an independent and identical distribution of the partial duration time series; this drawback is discussed in this paper. The Ganjiang River is the seventh largest tributary of the Yangtze River, the longest river in China. The Ganjiang River covers a drainage area of 81,258 km2 at the Wanzhou hydrologic station as the basin outlet. In this work, 56 years of daily flow data (1954-2009) from the Wanzhou station were used to analyze flood frequency, and the Pearson-III model was employed as the hydrologic probability distribution. Generally, three tasks were accomplished: (1) the threshold of PDS by percentile rank of daily runoff was obtained; (2) trend analysis of the flow series was conducted using PDS; and (3) flood frequency analysis was conducted for partial duration flow series. The results showed a slight upward trend of the annual runoff in the Ganjiang River basin. The maximum flow with a 0.01 exceedance probability (corresponding to a 100-year flood peak under stationary conditions) was 20,000 m3/s, while that with a 0.1 exceedance probability was 15,000 m3/s. These results will serve as a guide to hydrological engineering planning, design, and management for policymakers and decision makers associated with hydrology.

Examination of Direct Discharge Measurement Data and Historic Daily Data for Selected Gages on the Middle Mississippi River, 1861-2008

USGS Publications Warehouse

Huizinga, Richard J.

2009-01-01

An examination of data from two continuous stage and discharge streamgages and one continuous stage-only gage on the Middle Mississippi River was made to determine stage-discharge relation changes through time and to investigate cause-and-effect mechanisms through evaluation of hydraulic geometry, channel elevation and water-surface elevation data. Data from discrete, direct measurements at the streamgages at St. Louis, Missouri, and Chester, Illinois, during the period of operation by the U.S. Geological Survey from 1933 to 2008 were examined for changes with time. Daily stage values from the streamgages at St. Louis (1861-2008) and Chester (1891-2008) and the stage-only gage at Cape Girardeau, Missouri (1896-2008), throughout the historic period of record also were examined for changes with time. Stage and discharge from measurements and stage-discharge relations at the streamgages at St. Louis and Chester indicate that stage for a given discharge has changed with time at both locations. An apparent increase in stage for a given discharge at increased flows (greater than flood stage) likely is caused by the raising of levees on the flood plains, and a decrease in stage for a given discharge at low flows (less than one-half flood stage) likely is caused by a combination of dikes in the channel that deepen the channel thalweg at the end of the dikes, and reduced sediment flux into the Middle Mississippi River. Since the 1960s at St. Louis, Missouri, the stage-discharge relations indicated no change or a decrease in stage for a given discharge for all discharges, whereas at Chester, Illinois, the stage-discharge relations indicate increasing stage for a given discharge above bankfull because of sediment infilling of the overflow channel. Top width and average velocity from measurements at a given discharge for the streamgage at St. Louis, Missouri, were relatively constant through time, with the only substantial change in top width resulting from the change in measurement location from the Municipal/MacArthur Bridge to the Poplar Street Bridge in 1968. The average bed elevation appeared to be lowering with time at both measurement locations at St. Louis. Flow in the Horse Island Chute overflow channel for the streamgage at Chester, Illinois had an effect on top width and average velocity from measurements, and this effect changed with time as the inflow channel to Horse Island Chute filled with sediment. Top width from measurements at a given discharge was consistent through time at the Chester streamgage when adjusted to remove the part of the flow through Horse Island Chute. Average velocity from measurements at a given discharge appears to be increasing with time, possibly as a result of a series of dikes built or extended in the channel immediately upstream from the Chester streamgage; however, the average bed elevation for all discharges less than bankfull at the Chester streamgage fluctuate around an average value from 1948 to 2000, and the fluctuations appear to be related to the occurrence of moderate and large floods. Daily stage and discharge values available for the streamgage at St. Louis, Missouri, from 1861 to 1932 display distinct, fixed relations that change slightly with time before operation by the U.S. Geological Survey, indicating daily discharge was obtained from the daily stage value during this timeframe. A sudden and substantial reduction of about 24 percent at the upper end of the ratings for discharge at a given stage occurred between 1932 and 1933 when the U.S. Geological Survey began operating the streamgage. This change likely is the result of the change to Price AA current meters from other, less-accurate methods used for discharge measurements before 1933. Based on modeling results for the Middle Mississippi River by the U.S. Army Corps of Engineers and the findings of this study, the accuracy of the historic record before 1933 is questionable, and needs to be examined further. The differ

Dimensionless Numbers For Morphological, Thermal And Biogeochemical Controls Of Hyporheic Processes

NASA Astrophysics Data System (ADS)

Bellin, Alberto; Marzadri, Alessandra; Tonina, Daniele

2013-04-01

Transport of solutes and heat within the hyporheic zone are interface processes that gained growing attention in the last decade, when several modelling strategies have been proposed, mainly at the local or reach scale. We propose to upscale local hyporheic biogeochemical processes to reach and network scales by means of a Lagrangian modelling framework, which allows to consider the impact of the flow structure on the processes modelled. This analysis shows that geochemical processes can be parametrized through two new Damköhler numbers, DaO, and DaT. DaO = ?up,50-?lim is defined as the ratio between the median hyporheic residence time, ?up,50 and the time of consuming dissolved oxygen to a prescribed threshold concentration, ?lim, below which reductive reactions are activated. It quantifies the biogeochemical status of the hyporheic zone and could be a metric for upscaling local hyporheic biogeochemical processes to reach and river-network scale processes. In addition, ?up,50 is the time scale of hyporheic advection; while ?lim is the representative time scale of biogeochemical reactions and indicates the distance along the streamline, measured as the time needed to travel that distance, that a particle of water travels before the dissolved oxygen concentration declines to [DO]lim, the value at which denitrification is activated. We show that DaO is representative of the redox status and indicates whether the hyporheic zone is a source or a sink of nitrate. Values of DaO larger than 1 indicate prevailing anaerobic conditions, whereas values smaller than 1 prevailing aerobic conditions. Similarly, DaT quantifies the importance of the temperature daily oscillations of the stream water on the hyporheic environment. It is defined as the ratio between ?up,50, and the time limit at which the ratio between the amplitude of the temperature oscillation within the hyporheic zone (evaluated along the streamline) and in the stream water is smaller than e-1. We show that values of DaT > 1 indicate a thermally stable hyporheic zone, where organism metabolism is not influenced by surface water thermal oscillations and biogeochemical reaction rates depend on the mean daily stream water temperature. Values smaller than 1 suggest that organisms need to adapt to the daily thermal variations and biogeochemical reaction rates will depend on the daily fluctuations induced by stream water.

Changes in Water Quality of Grand Lake St. Marys Watershed Following Implementation of a Distressed Watershed Rules Package.

PubMed

Jacquemin, Stephen J; Johnson, Laura T; Dirksen, Theresa A; McGlinch, Greg

2018-01-01

Grand Lake St. Marys watershed has drawn attention over the past decade as water quality issues resulting from nutrient loading have come to the forefront of public opinion, political concern, and scientific study. The objective of this study was to assess long-term changes in water quality (nutrient and sediment concentrations) following the distressed watershed rules package instituted in 2011. Since that time, a variety of rules (e.g., winter manure ban) and best management practices (cover crops, manure storage or transfers, buffers, etc.) have been implemented. We used a general linear model to assess variation in total suspended solids, particulate phosphorus, soluble reactive phosphorus (SRP), nitrate N, and total Kjeldahl nitrogen concentrations from daily Chickasaw Creek (drains ∼25% of watershed) samples spanning 2008 to 2016. Parameters were related to flow (higher values during high flows), timing (lower values during winter months), and the implementation of the distressed watershed rules package (lower values following implementation). Overall, reductions following the distressed designation for all parameters ranged from 5 to 35% during medium and high flow periods (with exception of SRP). Reductions were even more pronounced during winter months covered by the manure ban, where all parameters (including SRP) exhibited decreases at medium and high flows between 20 and 60%. While the reductions seen in this study are significant, concentrations are still highly elevated and continue to be a problem. We are optimistic that this study will serve to inform future management in the region and elsewhere. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Extreme Value Theory and the New Sunspot Number Series

NASA Astrophysics Data System (ADS)

Acero, F. J.; Carrasco, V. M. S.; Gallego, M. C.; García, J. A.; Vaquero, J. M.

2017-04-01

Extreme value theory was employed to study solar activity using the new sunspot number index. The block maxima approach was used at yearly (1700-2015), monthly (1749-2016), and daily (1818-2016) scales, selecting the maximum sunspot number value for each solar cycle, and the peaks-over-threshold (POT) technique was used after a declustering process only for the daily data. Both techniques led to negative values for the shape parameters. This implies that the extreme sunspot number value distribution has an upper bound. The return level (RL) values obtained from the POT approach were greater than when using the block maxima technique. Regarding the POT approach, the 110 year (550 and 1100 year) RLs were lower (higher) than the daily maximum observed sunspot number value of 528. Furthermore, according to the block maxima approach, the 10-cycle RL lay within the block maxima daily sunspot number range, as expected, but it was striking that the 50- and 100-cycle RLs were also within that range. Thus, it would seem that the RL is reaching a plateau, and, although one must be cautious, it would be difficult to attain sunspot number values greater than 550. The extreme value trends from the four series (yearly, monthly, and daily maxima per solar cycle, and POT after declustering the daily data) were analyzed with the Mann-Kendall test and Sen’s method. Only the negative trend of the daily data with the POT technique was statistically significant.

Comparison of SWAT Hydrological Model Results from TRMM 3B42, NEXRAD Stage III, and Oklahoma Mesonet Data

NASA Astrophysics Data System (ADS)

Tobin, K. J.; Bennett, M. E.

2008-05-01

The Cimarron River Basin (3110 sq km) between Dodge and Guthrie, Oklahoma is located in northern Oklahoma and was used as a test bed to compare the hydrological model performance associated with different methods of precipitation quantification. The Soil and Water Assessment Tool (SWAT) was selected for this project, which is a comprehensive model that, besides quantifying watershed hydrology, can simulate water quality as well as nutrient and sediment loading within stream reaches. An advantage of this location is the extensive monitoring of MET parameters (precipitation, temperature, relative humidity, wind speed, solar radiation) afforded by the Oklahoma Mesonet, which has been documented to improve the performance of SWAT. The utility of TRMM 3B42 and NEXRAD Stage III data in supporting the hydrologic modeling of Cimarron River Basin is demonstrated. Minor adjustments to selected model parameters were made to make parameter values more realistic based on results from previous studies and information and to more realistically simulate base flow. Significantly, no ad hoc adjustments to major parameters such as Curve Number or Available Soil Water were made and robust simulations were obtained. TRMM and NEXRAD data are aggregated into an average daily estimate of precipitation for each TRMM grid cell (0.25 degree X 0.25 degree). Preliminary simulation of stream flow (year 2004 to 2006) in the Cimarron River Basin yields acceptable monthly results with very little adjustment of model parameters using TRMM 3B42 precipitation data (mass balance error = 3 percent; Monthly Nash-Sutcliffe efficiency coefficients (NS) = 0.77). However, both Oklahoma Mesonet rain gauge (mass balance error = 13 percent; Monthly NS = 0.91; Daily NS = 0.64) and NEXRAD Stage III data (mass balance error = -5 percent; Monthly NS = 0.95; Daily NS = 0.69) produces superior simulations even at a sub-monthly time scale; daily results are time averaged over a three day period. Note that all types of precipitation data perform better than a synthetic precipitation dataset generated using a weather simulator (mass balance error = 12 percent; Monthly NS = 0.40). Our study again documents that merged precipitation satellite products, such as TRMM 3B42, can support semi-distributed hydrologic modeling at the watershed scale. However, apparently additional work is required to improve TRMM precipitation retrievals over land to generate a product that yields more robust hydrological simulations especially at finer time scales. Additionally, ongoing work in this basin will compare TRMM results with stream flow model results generated using CMORPH precipitation estimates. Finally, in the future we plan to use simulated, semi-distributed soil moisture values determined by SWAT for comparison with gridded soil moisture estimates from TRMM-TMI that should provide further validation of our modeling efforts.

Estimating Evapotranspiration Demands of Different Land Cover Using Diurnal Signals in Dry Season Stream Discharge

NASA Astrophysics Data System (ADS)

Bhalla, R. S.; K, K.; Srinivas, V.; Krishnaswamy, J.; Chappell, N. A.; Jones, T.

2015-12-01

We use a paired catchment approach to compare the dry season flows between natural grasslands and introduced plantations of black wattle (Acacia mearnsii) in the Nilgiri South range forest which lies in the southern parts of the Western Ghat mountain range in Sothern India, a global biodiversity hot-spot. Discharges were measured using a portable flume and a weir fitted with capacitance probes logging water levels every five minutes in two adjacent catchments. Sensor artefacts in the data were filtered out before analysis. Diurnal variations in dry season flows from March 1st to April 15th, 2014 were used to estimate the daily ET based on Boronina et al. 2005 (Hyd. Proc. 19, 20, pp. 4055-4068.) using the equation 1. : E T daily = ∑ i=1 24 ( Q max - Q i ) Δ t , where E T daily is the daily loss of water from the catchment through ET, Q max is the daily maximum flow rate in the river, Q i is the average flow rate for every hour of the day and Δ t is one hour. Our results show that land use conversion from grasslands to wattle has increased ET by 40.97mm which is to the order of 60% during the period of the study (table 1). This has immediate relevance for dry season flows in the region. Nilgiris provide 40% of the total hydro-power generation for the state of Tamil Nadu and these streams sustain biodiversity and are tributaries of the Cauvery river, the largest the state. They also highlight the potential consequences of programmes such as the National Mission for Greening India which explicitly targets conversions of 10m ha of degraded forests, scrub and grasslands to tree cover and forest. Grassland Wattle Difference 1st Qu. 1.14 1.36 -1.33 Median 1.94 2.04 0.28 Mean 2.06 2.97 0.91 3rd Qu. 2.66 3.51 2.43 Sum 92.63 133.60 40.97 Table 1: Summary statistics for daily dry season ET for catchment under grassland, wattle and the daily differences between the two in mm per day.

Rainfall characteristics and thresholds for periglacial debris flows in the Parlung Zangbo Basin, southeast Tibetan Plateau

NASA Astrophysics Data System (ADS)

Deng, Mingfeng; Chen, Ningsheng; Ding, Haitao

2018-02-01

The Parlung Zangbo Basin in the southeastern Tibet Plateau is affected by the summer monsoon from the Indian Ocean, which produces large rainfall gradients in the basin. Rainfall data during 2012-2015 from five new meteorological stations are used to analyse the rainfall characteristics. The daily rainfall, rainfall duration, mean rainfall intensity, and peak rainfall intensity are consistent, but sometimes contrasting. For example, these values decrease with increasing altitude, and the gradient is large downstream and small upstream, respectively. Moreover, the rainfall intensity peaks between 01:00 and 06:00 and increases during the afternoon. Based on the analysis of 14 debris flow cases in the basin, differences in the rainfall threshold differ depending on the location as sediment varieties. The sediment in the middle portions of the basin is wet and well structured; thus, long-duration, high-intensity rainfall is required to generate debris flows. Ravels in the upstream area are arid and not well structured, and short-duration rainfall is required to trigger debris flows. Between the above two locations, either long-duration, low-intensity rainfall or short-duration, high-intensity rainfall could provoke debris flows. Clearly, differences in rainfall characteristics and rainfall thresholds that are associated with the location must be considered in debris flow monitoring and warnings.

Atmospheric circulation types and daily mortality in Athens, Greece.

PubMed Central

Kassomenos, P; Gryparis, A; Samoli, E; Katsouyanni, K; Lykoudis, S; Flocas, H A

2001-01-01

We investigated the short-term effects of synoptic and mesoscale atmospheric circulation types on mortality in Athens, Greece. The synoptic patterns in the lower troposphere were classified in 8 a priori defined categories. The mesoscale weather types were classified into 11 categories, using meteorologic parameters from the Athens area surface monitoring network; the daily number of deaths was available for 1987-1991. We applied generalized additive models (GAM), extending Poisson regression, using a LOESS smoother to control for the confounding effects of seasonal patterns. We adjusted for long-term trends, day of the week, ambient particle concentrations, and additional temperature effects. Both classifications, synoptic and mesoscale, explain the daily variation of mortality to a statistically significant degree. The highest daily mortality was observed on days characterized by southeasterly flow [increase 10%; 95% confidence interval (CI), 6.1-13.9% compared to the high-low pressure system), followed by zonal flow (5.8%; 95% CI, 1.8-10%). The high-low pressure system and the northwesterly flow are associated with the lowest mortality. The seasonal patterns are consistent with the annual pattern. For mesoscale categories, in the cold period the highest mortality is observed during days characterized by the easterly flow category (increase 9.4%; 95% CI, 1.0-18.5% compared to flow without the main component). In the warm period, the highest mortality occurs during the strong southerly flow category (8.5% increase; 95% CI, 2.0-15.4% compared again to flow without the main component). Adjusting for ambient particle levels leaves the estimated associations unchanged for the synoptic categories and slightly increases the effects of mesoscale categories. In conclusion, synoptic and mesoscale weather classification is a useful tool for studying the weather-health associations in a warm Mediterranean climate situation. PMID:11445513

Pressure-flow specificity of inspiratory muscle training.

PubMed

Tzelepis, G E; Vega, D L; Cohen, M E; Fulambarker, A M; Patel, K K; McCool, F D

1994-08-01

The inspiratory muscles (IM) can be trained by having a subject breathe through inspiratory resistive loads or by use of unloaded hyperpnea. These disparate training protocols are characterized by high inspiratory pressure (force) or high inspiratory flow (velocity), respectively. We tested the hypothesis that the posttraining improvements in IM pressure or flow performance are specific to training protocols in a way that is similar to force-velocity specificity of skeletal muscle training. IM training was accomplished in 15 normal subjects by use of three protocols: high inspiratory pressure-no flow (group A, n = 5), low inspiratory pressure-high flow (group B, n = 5), and intermediate inspiratory pressure and flow (group C, n = 5). A control group (n = 4) did no training. Before and after training, we measured esophageal pressure (Pes) and inspiratory flow (VI) during single maximal inspiratory efforts against a range of external resistances including an occluded airway. Efforts originated below relaxation volume (Vrel), and peak Pes and VI were measured at Vrel. Isovolume maximal Pes-VI plots were constructed to assess maximal inspiratory pressure-flow performance. Group A (pressure training) performed 30 maximal static inspiratory maneuvers at Vrel daily, group B (flow training) performed 30 sets of three maximal inspiratory maneuvers with no added external resistance daily, and group C (intermediate training) performed 30 maximal inspiratory efforts on a midrange external resistance (7 mm ID) daily. Subjects trained 5 days/wk for 6 wk. Data analysis included comparison of posttraining Pes-VI slopes among training groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Coupling climate and hydrological models to evaluate the impact of climate change on run of the river hydropower schemes from UK study sites

NASA Astrophysics Data System (ADS)

Pasten-Zapata, Ernesto; Jones, Julie; Moggridge, Helen

2015-04-01

As climate change is expected to generate variations on the Earth's precipitation and temperature, the water cycle will also experience changes. Consequently, water users will have to be prepared for possible changes in future water availability. The main objective of this research is to evaluate the impacts of climate change on river regimes and the implications to the operation and feasibility of run of the river hydropower schemes by analyzing four UK study sites. Run of the river schemes are selected for analysis due to their higher dependence to the available river flow volumes when compared to storage hydropower schemes that can rely on previously accumulated water volumes (linked to poster in session HS5.3). Global Climate Models (GCMs) represent the main tool to assess future climate change. In this research, Regional Climate Models (RCMs), which dynamically downscale GCM outputs providing higher resolutions, are used as starting point to evaluate climate change within the study catchments. RCM daily temperature and precipitation will be downscaled to an appropriate scale for impact studies and bias corrected using different statistical methods: linear scaling, local intensity scaling, power transformation, variance scaling and delta change correction. The downscaled variables will then be coupled to hydrological models that have been previously calibrated and validated against observed daily river flow data. The coupled hydrological and climate models will then be used to simulate historic river flows that are compared to daily observed values in order to evaluate the model accuracy. As this research will employ several different RCMs (from the EURO-CORDEX simulations), downscaling and bias correction methodologies, greenhouse emission scenarios and hydrological models, the uncertainty of each element will be estimated. According to their uncertainty magnitude, a prediction of the best downscaling approach (or approaches) is expected to be obtained. The current progress of the project will be presented along with the steps to be followed in the future.

Influence of septic systems on stream base flow in the Apalachicola-Chattahoochee-Flint River Basin near Metropolitan Atlanta, Georgia, 2012

USGS Publications Warehouse

Clarke, John S.; Painter, Jaime A.

2014-01-01

Septic systems were identified at 241,733 locations in a 2,539-square-mile (mi2) study area that includes all or parts of 12 counties in the Metropolitan Atlanta, Georgia, area. Septic system percolation may locally be an important component of streamflow in small drainage basins where it augments natural groundwater recharge, especially during extreme low-flow conditions. The amount of groundwater reaching streams depends on how much is intercepted by plants or infiltrates to deeper parts of the groundwater system that flows beyond a basin divide and does not discharge into streams within a basin. The potential maximum percolation from septic systems in the study area is 62 cubic feet per second (ft3/s), of which 52 ft3/s is in the Chattahoochee River Basin and 10 ft3/s is in the Flint River Basin. These maximum percolation rates represent 0.4 to 5.7 percent of daily mean streamflow during the 2011–12 period at the farthest downstream gaging site (station 02338000) on the Chattahoochee River, and 0.5 to 179 percent of daily mean streamflow at the farthest downstream gaging site on the Flint River (02344350). To determine the difference in base flow between basins having different septic system densities, hydrograph separation analysis was completed using daily mean streamflow data at streamgaging stations at Level Creek (site 02334578), with a drainage basin having relatively high septic system density of 101 systems per square mile, and Woodall Creek (site 02336313), with a drainage basin having relatively low septic system density of 18 systems per square mile. Results indicated that base-flow yield during 2011–12 was higher at the Level Creek site, with a median of 0.47 cubic feet per second per square mile ([ft3/s]/mi2), compared to a median of 0.16 (ft3/s)/mi2, at the Woodall Creek site. At the less urbanized Level Creek site, there are 515 septic systems with a daily maximum percolation rate of 0.14 ft3/s, accounting for 11 percent of the base flow in September 2012. At the more urban Woodall Creek site, there are 50 septic systems with an average daily maximum percolation rate of 0.0097 ft3/s, accounting for 5 percent of base flow in September 2012. Streamflow measurements at 133 small drainage basins (less than 5 mi2 in area) during September 2012 indicated no statistically significant difference in streamflow or specific conductance between basins having high and low density of septic systems (HDS and LDS, respectively). The median base-flow yield was 0.04 (f3/s)/mi2 for HDS sites, ranging from 0 to 0.52 (ft3/s)/mi2, and 0.10 (ft3/s)/mi2 for LDS sites, ranging from 0 to 0.49 (ft3/s)/mi2. A Wilcoxon rank-sum test indicated the median base-flow yields for HDS and LDS sites were not statistically different, with a p-value of 0.345. Because of the large size of the study area and associated variations in basin characteristics, data collected in September 2012 were also evaluated on the basis of the basins physical characteristics in an attempt to reduce or eliminate other basin characteristics that might affect base flow. Basins were evaluated based on geologic area, four geographic subareas, and 45-meter (147.6 ft) buffer zone; there were no statistically significant differences between median base-flow yield for HDS and LDS basins. It is probable that detection of the contribution from septic system percolation in base flow at many of the sites visited in September 2012 was obscured by a combination of the limitations of measurement accuracy and evapotranspiration. Detection of septic system percolation may also have been complicated by leaky water and sewer mains, which may have resulted in higher streamflows in LDS basins relative to HDS basins.

Trend analysis of hydro-climatic variables in the north of Iran

NASA Astrophysics Data System (ADS)

Nikzad Tehrani, E.; Sahour, H.; Booij, M. J.

2018-04-01

Trend analysis of climate variables such as streamflow, precipitation, and temperature provides useful information for understanding the hydrological changes associated with climate change. In this study, a nonparametric Mann-Kendall test was employed to evaluate annual, seasonal, and monthly trends of precipitation and streamflow for the Neka basin in the north of Iran over a 44-year period (1972 to 2015). In addition, the Inverse Distance Weight (IDW) method was used for annual seasonal, monthly, and daily precipitation trends in order to investigate the spatial correlation between precipitation and streamflow trends in the study area. Results showed a downward trend in annual and winter precipitation (Z < -1.96) and an upward trend in annual maximum daily precipitation. Annual and monthly mean flows for most of the months in the Neka basin decreased by 14% significantly, but the annual maximum daily flow increased by 118%. Results for the trend analysis of streamflow and climatic variables showed that there are statistically significant relationships between precipitation and streamflow (p value < 0.05). Correlation coefficients for Kendall, Spearman's rank and linear regression are 0.43, 0.61, and 0.67, respectively. The spatial presentation of the detected precipitation and streamflow trends showed a downward trend for the mean annual precipitation observed in the upstream part of the study area which is consistent with the streamflow trend. Also, there is a good correlation between monthly and seasonal precipitation and streamflow for all sub-basins (Sefidchah, Gelvard, Abelu). In general, from a hydro-climatic point of view, the results showed that the study area is moving towards a situation with more severe drought events.

A coupled synoptic-hydrological model for climate change impact assessment

NASA Astrophysics Data System (ADS)

Wilby, Robert; Greenfield, Brian; Glenny, Cathy

1994-01-01

A coupled atmospheric-hydrological model is presented. Sequences of daily rainfall occurrence for the 20 year period 1971-1990 at sites in the British Isles are related to the Lamb's Weather Types (LWT) by using conditional probabilities. Time series of circulation patterns and hence rainfall were then generated using a Markov representation of matrices of transition probabilities between weather types. The resultant precipitation data were used as input to a semidistributed catchment model to simulate daily flows. The combined model successfully reproduced aspects of the daily weather, precipitation and flow regimes. A range of synoptic scenarios were further investigated with particular reference to low flows in the River Coln, UK. The modelling approach represents a means of translating general circulation model (GCM) climate change predictions at the macro-scale into hydrological concerns at the catchment scale.

On the stability of the relationship between reference evapotranspiration and single tree transpiration: test and validation over several irrigated tree orchards

NASA Astrophysics Data System (ADS)

Ayyoub, Abdellatif; Er-Raki, Salah; Khabba, Saïd; Merlin, Olivier; César Rodriguez, Julio; Ezzahar, Jamal; Bahlaoui, Ahmed; Chehbouni, Abdelghani

2016-04-01

The present work aims to develop a simple approach relating normalized daily sap flow (per unit of leaf area) and daily ET0 (mm/day) calculated by two methods: FAO-Penman-Monteith (FAO-PM) and Hargreaves-Samani (HARG). The data sets used for developing this approach are taken from three experimental sites (olive trees, cv. "Oleaeuropaea L.", olive trees, cv. "Arbequino" and citrus trees cv. "Clementine Afourar") conducted in the Tensift region around Marrakech, Morocco and one experimental site (pecan orchard, cv. "Caryaillinoinensis, Wangenh. K. Koch") conducted in the Yaqui Valley, northwest of Mexico). The results showed that the normalized daily sap flow (volume of transpired water per unit of leaf area) was linearly correlated with ET0 (mm per day) calculated by FAO-PM method. The coefficient of determination (R2) and the slope of this linear regression varied between 0.71 and 0.97 and between 0.30 and 0.35, respectively, depending on the type of orchards. For HARG method, the relationship between both terms is also linear but with less accuracy (R2 =0.7) as expected due to the underestimation of ET0 by this method. Afterward, the validation of the developed linear relationship was performed over an olive orchard ("Oleaeuropaea L.") where the measurements of sap flow were available for another (2004) cropping season. The scatter plot between the normalized measured and estimated sap flow based on FAO-PM method reveals a very good agreement (slope = 1, with R2 = 0.83 and RMSE=0.14 L/m2 leaf area). However, for the estimation of normalized sap flow based on HARG method, the correlation is more scattered with some underestimation (5%). A further validation wasperformed using the measurements of evapotranspiration (ET) by eddy correlation system and the results showed that the correlation between normalized measured ET and estimated normalized sap flow is best when using FAO-PM method (RMSE=0.33 L/m2 leaf area) for estimating ET0 than when using HARG method (RMSE= 0.51 L/m2 leaf area). Finally, the performance of the developed approach was compared to the traditional dual crop coefficient scheme for estimating plant transpiration. Cross-comparison of these two approaches with the measurements data gave satisfactory results with an average value of RMSE equal to about 0.37 mm/day for both approaches.

Retrieving atmospheric transmissivity for biologically active daily dose, in various european sites

NASA Astrophysics Data System (ADS)

de La Casinière, A.; Touré, M. L.; Lenoble, J.; Cabot, T.

2003-04-01

In the frame of the European Project EDUCE, global UV irradiance spectra recorded all along the year in several European sites are stored in a common database located in Finland. From the spectra set of some of these stations, are calculated atmospheric transmissivities for daily doses of four biologically active UV radiation, namely: UV-B, erythema, DNA damage, and plant damage. A transmissivity is defined as the ratio of the ground level value of the daily dose of interest to its corresponding extra-atmospheric value. Multiple linear correlation of the various transmissivities with three predictors (daily sunshine fraction, cosine of the daily minimum SZA, and daily total ozone column) assumed to be independent variables, are done for year 2000. The coefficients obtained from year 2000 correlation in a given site are expected to retrieve, from the local predictors, the daily dose for year 2001 in the same site, the average error being lesser than 10% for monthly mean values, and lesser than 5% for three-monthly mean values, depending on the daily dose type. Comparison of yearly mean daily doses retrieved in a given site from coefficients obtained in other sites is also presented.

The Value of Hydrograph Partitioning Curves for Calibrating Hydrological Models in Glacierized Basins

NASA Astrophysics Data System (ADS)

He, Zhihua; Vorogushyn, Sergiy; Unger-Shayesteh, Katy; Gafurov, Abror; Kalashnikova, Olga; Omorova, Elvira; Merz, Bruno

2018-03-01

This study refines the method for calibrating a glacio-hydrological model based on Hydrograph Partitioning Curves (HPCs), and evaluates its value in comparison to multidata set optimization approaches which use glacier mass balance, satellite snow cover images, and discharge. The HPCs are extracted from the observed flow hydrograph using catchment precipitation and temperature gradients. They indicate the periods when the various runoff processes, such as glacier melt or snow melt, dominate the basin hydrograph. The annual cumulative curve of the difference between average daily temperature and melt threshold temperature over the basin, as well as the annual cumulative curve of average daily snowfall on the glacierized areas are used to identify the starting and end dates of snow and glacier ablation periods. Model parameters characterizing different runoff processes are calibrated on different HPCs in a stepwise and iterative way. Results show that the HPC-based method (1) delivers model-internal consistency comparably to the tri-data set calibration method; (2) improves the stability of calibrated parameter values across various calibration periods; and (3) estimates the contributions of runoff components similarly to the tri-data set calibration method. Our findings indicate the potential of the HPC-based approach as an alternative for hydrological model calibration in glacierized basins where other calibration data sets than discharge are often not available or very costly to obtain.

Daily nursing care on patients undergoing venous-venous extracorporeal membrane oxygenation: a challenging procedure!

PubMed

Redaelli, Sara; Zanella, Alberto; Milan, Manuela; Isgrò, Stefano; Lucchini, Alberto; Pesenti, Antonio; Patroniti, Nicolò

2016-12-01

Daily nursing in critical care patients may alter vital parameters, especially in the most critically ill patients. The aim of our study was to evaluate feasibility and safety of daily nursing on patients undergoing venous-venous extracorporeal membrane oxygenation (vv-ECMO) for severe respiratory failure. Daily nursing was performed following defined phases (sponge bath, elevation with scooping stretcher, change position of endotracheal tube, dressing replacement). We recorded physiological and ECMO parameters before and during daily nursing in 5 patients for several days (total: 25 daily nursing) and adverse events: desaturation, hypertension, reduction of mixed venous oxygen saturation, arterial oxygen saturation or ECMO blood flow and elevation in minute ventilation. Sedative drug dosage and additional bolus were recorded. Daily nursing was performed in 92 % of cases (23/25), with a minimum of two adverse events per daily nursing. Hypertension and tachycardia were mostly recorded at the beginning, while desaturation, reduction in mixed venous oxygen saturation and blood flow were recorded during elevation with scooping stretcher. Increase in minute ventilation was frequent in spontaneous breathing patients. Additional bolus of sedation was required before and/or during nursing. Daily nursing significantly alters physiologic parameters; thus, it should be performed only when physicians are readily available to treat adverse events.

Design flow factors for sewerage systems in small arid communities.

PubMed

Imam, Emad H; Elnakar, Haitham Y

2014-09-01

Reliable estimation of sewage flow rates is essential for the proper design of sewers, pumping stations, and treatment plants. The design of the various components of the sewerage system should be based on the most critical flow rates with a focus on extremely low and peak flow rates that would be sustained for a duration related to the acceptable limits of behavior of the components under consideration. The extreme flow conditions and to what extent they differ from the average values are closely related to the size of the community or network, and the socioeconomic conditions. A single pumping station is usually sufficient to pump flow from small community in either flat or non-undulating topography. Therefore, the hydraulic loading on the wastewater treatment plant (WWTP) results from the pumped flow from the pumping station rather than the trunk sewer flow. The intermittent operation of the pumping units further accentuates the sewage hydrograph in the final trunk sewer. Accordingly, the design flow for the various components of the WWTP should be determined based on their relevant flow factors. In this study, analysis of one representative small community out of five monitored small communities in Egypt and the Kingdom of Saudi Arabia is presented. Pumped sewage flow rates were measured and the sewer incoming flows were hydraulically derived. The hourly and daily sewer and pumped flow records were analyzed to derive the relationship between the flow factors that would be sustained for various durations (instantaneously, 1 h, 2 h, etc.) and their probability of non-exceedance. The resulting peaking factors with a consideration for their sustained flow duration and specified probability would permit the design of the various components of the treatment plant using more accurate critical flows.

Design flow factors for sewerage systems in small arid communities

PubMed Central

Imam, Emad H.; Elnakar, Haitham Y.

2013-01-01

Reliable estimation of sewage flow rates is essential for the proper design of sewers, pumping stations, and treatment plants. The design of the various components of the sewerage system should be based on the most critical flow rates with a focus on extremely low and peak flow rates that would be sustained for a duration related to the acceptable limits of behavior of the components under consideration. The extreme flow conditions and to what extent they differ from the average values are closely related to the size of the community or network, and the socioeconomic conditions. A single pumping station is usually sufficient to pump flow from small community in either flat or non-undulating topography. Therefore, the hydraulic loading on the wastewater treatment plant (WWTP) results from the pumped flow from the pumping station rather than the trunk sewer flow. The intermittent operation of the pumping units further accentuates the sewage hydrograph in the final trunk sewer. Accordingly, the design flow for the various components of the WWTP should be determined based on their relevant flow factors. In this study, analysis of one representative small community out of five monitored small communities in Egypt and the Kingdom of Saudi Arabia is presented. Pumped sewage flow rates were measured and the sewer incoming flows were hydraulically derived. The hourly and daily sewer and pumped flow records were analyzed to derive the relationship between the flow factors that would be sustained for various durations (instantaneously, 1 h, 2 h, etc.) and their probability of non-exceedance. The resulting peaking factors with a consideration for their sustained flow duration and specified probability would permit the design of the various components of the treatment plant using more accurate critical flows. PMID:25685521

Does Arterial Spin-labeling MR Imaging–measured Tumor Perfusion Correlate with Renal Cell Cancer Response to Antiangiogenic Therapy in a Mouse Model?

PubMed Central

Schor-Bardach, Rachel; Alsop, David C.; Pedrosa, Ivan; Solazzo, Stephanie A.; Wang, Xiaoen; Marquis, Robert P.; Atkins, Michael B.; Regan, Meredith; Signoretti, Sabina; Lenkinski, Robert E.; Goldberg, S. Nahum

2009-01-01

Purpose: To determine whether arterial spin-labeling (ASL) magnetic resonance (MR) imaging findings at baseline and early during antiangiogenic therapy can predict later resistance to therapy. Materials and Methods: Protocol was approved by an institutional animal care and use committee. Caki-1, A498, and 786-0 human renal cell carcinoma (RCC) xenografts were implanted in 39 nude mice. Animals received 80 mg sorafenib per kilogram of body weight once daily once tumors measured 12 mm. ASL imaging was performed at baseline and day 14, with additional imaging performed for 786-0 and A498 (3 days to 12 weeks). Mean blood flow values and qualitative differences in spatial distribution of blood flow were analyzed and compared with histopathologic findings for viability and microvascular density. t Tests were used to compare differences in mean tumor blood flow. Bonferroni-adjusted P values less than .05 denoted significant differences. Results: Baseline blood flow was 80.1 mL/100 g/min ± 23.3 (standard deviation) for A498, 75.1 mL/100 g/min ± 28.6 for 786-0, and 10.2 mL/100 g/min ± 9.0 for Caki-1. Treated Caki-1 showed no significant change (14.9 mL/100 g/min ± 7.6) in flow, whereas flow decreased in all treated A498 on day 14 (47.9 mL/100 g/min ± 21.1) and in 786-0 on day 3 (20.3 mL/100 g/min ± 8.7) (P = .003 and .03, respectively). For A498, lowest values were measured at 28–42 days of receiving sorafenib. Regions of increased flow occurred on days 35–49, 17–32 days before documented tumor growth and before significant increases in mean flow (day 77). Although 786-0 showed new, progressive regions with signal intensity detected as early as day 5 that correlated to viable tumor at histopathologic examination, no significant changes in mean flow were noted when day 3 was compared with all subsequent days (P > .99). Conclusion: ASL imaging provides clinically relevant information regarding tumor viability in RCC lines that respond to sorafenib. © RSNA, 2009 PMID:19474376

Managing length of stay using patient flow--part 1.

PubMed

Cesta, Toni

2013-02-01

This month we have discussed the fundamentals of patient flow and its related theories. We reviewed the concepts of demand and capacity management as they apply to the hospital setting. Patient flow requires daily diligence and attention. It should not be something focused on only on busy days, but should be managed each and every day. By taking a proactive approach to patient flow, the number of days your hospital will be bottlenecked can be reduced. Patient flow needs to be part of the daily activities of every case management department and should be factored in as a core role and function in a contemporary case management department. Patient flow needs to be addressed at the patient, departmental, and hospital level. In next month's issue we will continue our discussion on patient flow with a detailed review of specific examples that any case management department can use. We will also review all the departments and disciplines that contribute to patient flow and their role in it.

Environmental flow studies of the Fort Collins Science Center, U.S. Geological Survey-Cherry Creek, Arizona

USGS Publications Warehouse

Waddle, Terry J.; Bovee, Ken D.

2010-01-01

At the request of the U.S. Forest Service, an instream flow assessment was conducted at Cherry Creek, Ariz., to investigate habitat for native and introduced fish species and to describe the beneficial use of a possible instream flow water right. The U.S. Geological Survey (USGS) Fort Collins Science Center performed an intensive field study of two sections of Cherry Creek in September 2008 to provide base data for hydrodynamic simulation of the flow conditions in the stream. The USGS Arizona Cooperative Fish and Wildlife Research Unit, at the University of Arizona School of Natural Resources, conducted a survey of the habitat requirements of the resident fish species in Cherry Creek and provided the habitat suitability criteria used in this study. The habitat suitability criteria were combined with hydrodynamic simulation results to quantify fish habitat for the full range of daily flow experienced in the creek and to produce maps of habitat occurrence for those flows. The flow record at the Cherry Creek stream gage was used to generate habitat response values over time. The long-term habitat response was incorporated into an Excel (Registered) spreadsheet to allow evaluation of habitat occurrence with and without an instream water right under different hypothetical water withdrawal scenarios. The spreadsheet displays information about the time sequence of habitat events, the duration of critical events, and habitat retention.

Evaluation of medium-range ensemble flood forecasting based on calibration strategies and ensemble methods in Lanjiang Basin, Southeast China

NASA Astrophysics Data System (ADS)

Liu, Li; Gao, Chao; Xuan, Weidong; Xu, Yue-Ping

2017-11-01

Ensemble flood forecasts by hydrological models using numerical weather prediction products as forcing data are becoming more commonly used in operational flood forecasting applications. In this study, a hydrological ensemble flood forecasting system comprised of an automatically calibrated Variable Infiltration Capacity model and quantitative precipitation forecasts from TIGGE dataset is constructed for Lanjiang Basin, Southeast China. The impacts of calibration strategies and ensemble methods on the performance of the system are then evaluated. The hydrological model is optimized by the parallel programmed ε-NSGA II multi-objective algorithm. According to the solutions by ε-NSGA II, two differently parameterized models are determined to simulate daily flows and peak flows at each of the three hydrological stations. Then a simple yet effective modular approach is proposed to combine these daily and peak flows at the same station into one composite series. Five ensemble methods and various evaluation metrics are adopted. The results show that ε-NSGA II can provide an objective determination on parameter estimation, and the parallel program permits a more efficient simulation. It is also demonstrated that the forecasts from ECMWF have more favorable skill scores than other Ensemble Prediction Systems. The multimodel ensembles have advantages over all the single model ensembles and the multimodel methods weighted on members and skill scores outperform other methods. Furthermore, the overall performance at three stations can be satisfactory up to ten days, however the hydrological errors can degrade the skill score by approximately 2 days, and the influence persists until a lead time of 10 days with a weakening trend. With respect to peak flows selected by the Peaks Over Threshold approach, the ensemble means from single models or multimodels are generally underestimated, indicating that the ensemble mean can bring overall improvement in forecasting of flows. For peak values taking flood forecasts from each individual member into account is more appropriate.

Deterministic chaotic dynamics of Raba River flow (Polish Carpathian Mountains)

NASA Astrophysics Data System (ADS)

Kędra, Mariola

2014-02-01

Is the underlying dynamics of river flow random or deterministic? If it is deterministic, is it deterministic chaotic? This issue is still controversial. The application of several independent methods, techniques and tools for studying daily river flow data gives consistent, reliable and clear-cut results to the question. The outcomes point out that the investigated discharge dynamics is not random but deterministic. Moreover, the results completely confirm the nonlinear deterministic chaotic nature of the studied process. The research was conducted on daily discharge from two selected gauging stations of the mountain river in southern Poland, the Raba River.

Salt-front movement in the Hudson River estuary, New York—Simulations by one-dimensional flow and solute-transport models

USGS Publications Warehouse

de Vries, M. Peter; Weiss, Lawrence A.

2001-01-01

The Hudson River is being considered for use as a supplemental source of water supply for New York City during droughts. One proposal entails withdrawal of Hudson River water from locations near Newburgh, Chelsea, or Kingston, but the extent to which this could cause the salt front to advance upstream to points where it could adversely affect community water supplies is unknown. The U.S. Geological Survey (USGS) one-dimensional Branch-Network Dynamic Flow model (BRANCH) was used in conjunction with the USGS one-dimensional Branched Lagrangian Solute-Transport Model (BLTM) to simulate the effect of five water-withdrawal scenarios on the salt-front location.The modeled reach contains 132 miles of the lower Hudson River between the Federal Dam at Troy and Hastings-on-Hudson (near New York City). The BRANCH model was calibrated and verified to 19 tidal-cycle discharge measurements made at 11 locations by conventional and acoustic Doppler current-profiler methods. Maximum measured instantaneous tidal flow ranged from 20,000 ft3/s (cubic feet per second) at Albany to 368,000 ft3/s at Tellers Point; daily-mean flow at Green Island near Troy ranged from 3,030 ft3/s to 45,000 ft3/s during the flow measurements. Successive ebb- and flood-flow volumes were measured and compared with computed volumes; daily-mean bias was -1.6 percent (range from -21.0 to +23.7 percent; 13.5 percent mean absolute error). Daily-mean deviation between simulated and measured stage at eight locations (from Bowline Point to Albany) over the 19 tidal-cycle measurements averaged +0.06 ft (range from -0.31 to +0.40 ft; 0.21 ft root mean square error, RMSE). These results indicate that the model can accurately simulate flow in the Hudson River under a wide range of flow, tide, and meteorological conditions.The BLTM was used to simulate chloride transport in the 61-mi reach from Turkey Point to Bowline Point under two seasonal conditions in 1990.one representing spring conditions of high inflow and low salinity (April-June), the other representing typical summer conditions of low inflow and high salinity (July-August). Measured chloride concentrations at Bowline Point were used to drive the BLTM simulations, and data collected at West Point were used for calibration. Mean bias in simulated chloride concentration for the April-June 1990 (high flow) data (observed range from 12 to 201 mg/L [milligrams per liter]; 30 mg/L RMSE) was .16 mg/L, and mean bias for the July-August 1990 (low flow) data (observed range from 31 to 2,000 mg/L; 535 mg/ L RMSE) was +126 mg/L. The salt front (saltwater/ freshwater interface) on the Hudson River was defined as the furthest upstream location where the chloride concentration exceeded 100 mg/L. Data from August 1991 were used to evaluate solute transport between West Point and Poughkeepsie because a chloride concentration of 100 mg/L was not observed at Clinton Point in 1990. The BLTM then was used to simulate chloride concentrations at Chelsea Pump Station and Clinton Point. Regression equations, based on daily mean values of specific conductance measured at West Point, were used to estimate daily mean chloride concentrations at Chelsea Pump Station and Clinton Point for model analysis. Mean biases in BLTM-simulated daily mean chloride concentrations for August 1991 were .38 mg/L at Chelsea Pump Station (range from 189 to 551 mg/L; 103 mg/L RMSE) and .9 mg/L at Clinton Point (range from 53 to 264 mg/L; 62 mg/L RMSE).Hypothetical withdrawals at (1) Newburgh, (2) Chelsea, (3) Chelsea and Newburgh, (4) Chelsea and Kingston, and (5) Kingston and Newburgh, were simulated to compute the effects of withdrawals on salt-front movement. Withdrawals of 300 Mgal/d from any combination of Chelsea or Newburgh could result in upstream movement of the salt front of as much as 1.0 mi, given an initial salt-front location between West Point and Rogers Point. Scenarios that included withdrawals at Kingston caused the greatest upstream salt-front movement. Simulation of a 90-day April-June high-flow period during which discharges at Green Island averaged 25,200 ft3/s indicated that withdrawals of 1,939 Mgal/d (million gallons per day) at Chelsea Pump Station would not measureably increase chloride concentrations at Chelsea Pump Station under normal tidal and meteorological conditions, but withdrawals at twice that rate (3,878 Mgal/d) could increase the chloride concentration at Chelsea Pump Station to 250 mg/L.

Summary of Flow Loss between Selected Cross Sections on the Rio Grande in and near Albuquerque, New Mexico

USGS Publications Warehouse

Veenhuis, Jack E.

2002-01-01

The upper middle Rio Grande Basin, as defined by the U.S. Army Corps of Engineers, extends from the headwaters of the Rio Grande in southwestern Colorado to Fort Quitman, Texas. Most of the basin has a semiarid climate typical of the southwestern United States. This climate drives a highly variable streamflow regime that contributes to the complexity of water management in the basin. Currently, rapid population growth in the basin has resulted in increasing demands on the hydrologic system. Water management decisions have become increasingly complex because of the broad range of interests and issues. For these reasons, the U.S. Geological Survey, in cooperation with the City of Albuquerque, New Mexico, conducted paired flow measurements at two cross sections to determine cross-sectional loss in the Albuquerque reach of the Rio Grande. This report statistically summarizes flow losses in the Albuquerque reach of the Rio Grande during the winter nonirrigation season from December 1996 to February 2000. The two previous flow-loss investigations are statistically summarized. Daily mean flow losses are calculated for the winter nonirrigation season using daily mean flows at three selected Rio Grande streamflow-gaging stations.For the winter nonirrigation season cross-sectional measurements (1996-2000), an average of 210 cubic feet per second was returned to the river between the measurement sites, of which 165 cubic feet per second was intercepted by riverside drains along the 21.9-mile reach from the Rio Grande near Bernalillo to the Rio Grande at Rio Bravo Bridge streamflow-gaging stations. Total cross-sectional losses in this reach averaged about 90 cubic feet per second. Regression equations were determined for estimating downstream total outflow from upstream total inflow for all three paired measurement studies. Regression equations relating the three daily mean flow recording stations also were determined. In each succeeding study, additional outside variables were controlled, which provided more accurate flow-loss measurements. Regression-equation losses between measurement cross sections ranged from 1.9 to 7.9 percent during the nonirrigation season and from about 5.9 to 6.4 percent during the irrigation season. Mean and median loss by reach length for all three daily mean flow stations and all three cross-sectional measurement reaches showed consistent flow loss per mile by season with allowance for nonideal river conditions for the initial measurement studies. Unsteady measurement conditions were reflected in the regression equation mean-square errors and ultimately in the change in daily mean discharge at the Rio Grande at Albuquerque gaging station during the measurement periods.

Hydrometeorological daily recharge assessment model (DREAM) for the Western Mountain Aquifer, Israel: Model application and effects of temporal patterns

NASA Astrophysics Data System (ADS)

Sheffer, N. A.; Dafny, E.; Gvirtzman, H.; Navon, S.; Frumkin, A.; Morin, E.

2010-05-01

Recharge is a critical issue for water management. Recharge assessment and the factors affecting recharge are of scientific and practical importance. The purpose of this study was to develop a daily recharge assessment model (DREAM) on the basis of a water balance principle with input from conventional and generally available precipitation and evaporation data and demonstrate the application of this model to recharge estimation in the Western Mountain Aquifer (WMA) in Israel. The WMA (area 13,000 km2) is a karst aquifer that supplies 360-400 Mm3 yr-1 of freshwater, which constitutes 20% of Israel's freshwater and is highly vulnerable to climate variability and change. DREAM was linked to a groundwater flow model (FEFLOW) to simulate monthly hydraulic heads and spring flows. The models were calibrated for 1987-2002 and validated for 2003-2007, yielding high agreement between calculated and measured values (R2 = 0.95; relative root-mean-square error = 4.8%; relative bias = 1.04). DREAM allows insights into the effect of intra-annual precipitation distribution factors on recharge. Although annual precipitation amount explains ˜70% of the variability in simulated recharge, analyses with DREAM indicate that the rainy season length is an important factor controlling recharge. Years with similar annual precipitation produce different recharge values as a result of temporal distribution throughout the rainy season. An experiment with a synthetic data set exhibits similar results, explaining ˜90% of the recharge variability. DREAM represents significant improvement over previous recharge estimation techniques in this region by providing near-real-time recharge estimates that can be used to predict the impact of climate variability on groundwater resources at high temporal and spatial resolution.

Estimated Loads of Suspended Sediment and Selected Trace Elements Transported through the Milltown Reservoir Project Area Before and After the Breaching of Milltown Dam in the Upper Clark Fork Basin, Montana, Water Year 2008

USGS Publications Warehouse

Lambing, John H.; Sando, Steven K.

2009-01-01

This report presents estimated daily and cumulative loads of suspended sediment and selected trace elements transported during water year 2008 at three streamflow-gaging stations that bracket the Milltown Reservoir project area in the upper Clark Fork basin of western Montana. Milltown Reservoir is a National Priorities List Superfund site where sediments enriched in trace elements from historical mining and ore processing have been deposited since the construction of Milltown Dam in 1907. Milltown Dam was breached on March 28, 2008, as part of Superfund remedial activities to remove the dam and contaminated sediment that had accumulated in Milltown Reservoir. The estimated loads transported through the project area during the periods before and after the breaching of Milltown Dam, and for the entire water year 2008, were used to quantify the net gain or loss (mass balance) of suspended sediment and trace elements within the project area during the transition from a reservoir environment to a free-flowing river. This study was done in cooperation with the U.S. Environmental Protection Agency. Streamflow during water year 2008 compared to long-term streamflow, as represented by the record for Clark Fork above Missoula (water years 1930-2008), generally was below normal (long-term median) from about October 2007 through April 2008. Sustained runoff started in mid-April, which increased flows to near normal by mid-May. After mid-May, flows sharply increased to above normal, reaching a maximum daily mean streamflow of 16,800 cubic feet per second (ft3/s) on May 21, which essentially equaled the long-term 10th-exceedance percentile for that date. Flows substantially above normal were sustained through June, then decreased through the summer and reached near-normal by August. Annual mean streamflow during water year 2008 (3,040 ft3/s) was 105 percent of the long-term mean annual streamflow (2,900 ft3/s). The annual peak flow (17,500 ft3/s) occurred on May 21 and was 112 percent of the long-term mean annual peak flow (15,600 ft3/s). About 81 percent of the annual flow volume was discharged during the post-breach period. Daily loads of suspended sediment were estimated directly by using high-frequency sampling of the daily sediment monitoring. Daily loads of unfiltered-recoverable arsenic, cadmium, copper, iron, lead, manganese, and zinc were estimated by using regression equations relating trace-element discharge to either streamflow or suspended-sediment discharge. Regression equations for estimating trace-element discharge in water year 2008 were developed from instantaneous streamflow and concentration data for periodic water-quality samples collected during all or part of water years 2004-08. The equations were applied to records of daily mean streamflow or daily suspended-sediment loads to produce estimated daily trace-element loads. Variations in daily suspended-sediment and trace-element loads generally coincided with variations in streamflow. Relatively small to moderately large daily net losses from the project area were common during the pre-breach period when low-flow conditions were prevalent. Outflow loads from the project area sharply increased immediately after the breaching of Milltown Dam and during the rising limb and peak flow of the annual hydrograph. Net losses of suspended sediment and trace elements from the project area decreased as streamflow decreased during the summer, eventually becoming small or reaching an approximate net balance between inflow and outflow. Estimated daily loads of suspended sediment and trace elements for all three stations were summed to determine cumulative inflow and outflow loads for the pre-breach and post-breach periods, as well as for the entire water year 2008. Overall, the mass balance between the combined inflow loads from two upstream source areas (upper Clark Fork and Blackfoot River basins) and the outflow loads at Clark Fork above Missoula indicates net losses

Spatially explicit simulation of peatland hydrology and carbon dioxide exchange: Influence of mesoscale topography

NASA Astrophysics Data System (ADS)

Sonnentag, O.; Chen, J. M.; Roulet, N. T.; Ju, W.; Govind, A.

2008-06-01

Carbon dynamics in peatlands are controlled, in large part, by their wetness as defined by water table depth and volumetric liquid soil moisture content. A common type of peatland is raised bogs that typically have a multiple-layer canopy of vascular plants over a Sphagnum moss ground cover. Their convex form restricts water supply to precipitation and water is shed toward the margins, usually by lateral subsurface flow. The hydraulic gradient for lateral subsurface flow is governed by the peat surface topography at the mesoscale (˜200 m to 5 km). To investigate the influence of mesoscale topography on wetness, evapotranspiration (ET), and gross primary productivity (GPP) in a bog during the snow-free period, we compare the outputs of a further developed version of the daily Boreal Ecosystem Productivity Simulator (BEPS) with observations made at the Mer Bleue peatland, located near Ottawa, Canada. Explicitly considering mesoscale topography, simulated total ET and GPP correlate well with measured ET (r = 0.91) and derived gross ecosystem productivity (GEP; r = 0.92). Both measured ET and derived GEP are simulated similarly well when mesoscale topography is neglected, but daily simulated values are systematically underestimated by about 10% and 12% on average, respectively, due to greater wetness resulting from the lack of lateral subsurface flow. Owing to the differences in moss surface conductances of water vapor and carbon dioxide with increasing moss water content, the differences in the spatial patterns of simulated total ET and GPP are controlled by the mesotopographic position of the moss ground cover.

Effect of 1,6-hexamethylene diisocyanate exposure on peak flowmetry in automobile paint shop workers in Iran.

PubMed

Pourabedian, Siyamak; Barkhordari, Abdullah; Habibi, Ehsanallah; Rismanchiyan, Masoud; Zare, Mohsen

2010-06-01

The aim of this study was to investigate the effects of occupational exposure to 1,6-hexamethylene diisocyanate (HDI) on peak flowmetry in automobile body paint shop workers in Iran. We studied a population of 43 car painters exposed to HDI at their workplaces. Peak expiratory flow was tested for one working week, from the start to the end of each shift. Air was sampled and HDI analysed in parallel, according to the OSHA 42 method. Daily and weekly HDI exposure averages were (0.42+/-0.1) mg m(-3) and (0.13+/-0.05) mg m(-3), respectively. On painting days, 72 % of workers showed more than a 10 % variation in peak expiratory flow. Inhalation exposure exceeded the threshold limit value (TLV) ten times over. This strongly suggests that HDI affected the peak flowmetry in the studied workers.

[Home Daily Hemodialysis with NxStage System One: monocentric italian casistic results].

PubMed

Brunati, Chiara; Cassaro, Franca; Cretti, Laura; Izzo, Michela; Pegoraro, Marisa; Negri, Daniela; Gervasi, Francesca; Colussi, Giacomo

2017-09-28

NxStage System One is a new dialytic technology based on easy setup, simplicity of use and reduced dimensions, which is increasingly in use worldwide for home hemodialysis treatments. The system utilizes a low amount of dialysate, usually 15-30 liters according to anthropometric patients' values. The dialysate is supplied at very low flux, generally about 1/3 of blood flow, in order to obtain an elevated saturation of dialysate for solutes. In these conditions the clearance of urea will be almost equal to dialysate flow rate. In order to achieve an obptimal weekly clearance evaluated by Std Kt/V the dialysis sessions are repeated six times a week. In this way a good control of blood voleme can be reached. In this paper we report our experience of treatment with NxStage System One in 12 patients from May 2011 to Dicember 2016. Copyright by Società Italiana di Nefrologia SIN, Rome, Italy.

Recherche d'une politique de gestion des stocks d'eau de barrages-réservoirs en vue de soutenir les étiages. 1. Élaboration d'un modèle alterné annuel apports-déficits

NASA Astrophysics Data System (ADS)

Bocquillon, C.; Masson, J. M.

1983-01-01

Lack of water supply during periods of deficient flow affects the economic potentiality of the great river valleys which are the most developed areas in the country. Reservoir dams built in the upper stream catchments store excess flow and provide controlled release in the dry season. Capital costs of construction and the consequences of failures justify a thorough study of operating rules. The low flows and conditional variability of availability of water call for carry-over procedures (reservoir capacity is sometimes greater than the mean available water). It is not possible to predict future sequence of flows, thus the carry-over rule is a statistical decision-making tool. The flow data are only one of the very many possible sources of information. But the analysis of flow data provides us with statistical measures to generate long series of synthetic inflows associated with summer deficits. A simplification has been introduced by choosing only the values which are absolutely necessary for optimal management research: available water volumes and reserve volumes for a flow threshold. Yearly alternate periods of excess and deficiency of water are defined by the values above and below a threshold of flow discharge at a location gage named "objective point", where the reservoir effects are to be estimated. Yearly periods are described by water volumes, either inflows into reservoirs, or deficits below various thresholds of summer flow discharges. Marginal and conditional probability distributions of these volumes and the physical laws which mark their bounds and relationships were estimated on the basis of 31 years of daily flow records. The synthetic simulated series for 1000 years was compared to records of historical levels (since 1863). Extreme events such as sequences of dry years, have return periods of comparable magnitude. This synthetic series has a similar statistical character of short historical series and makes the analysis of operating rules possible.

Methods for estimating selected low-flow statistics and development of annual flow-duration statistics for Ohio

USGS Publications Warehouse

Koltun, G.F.; Kula, Stephanie P.

2013-01-01

This report presents the results of a study to develop methods for estimating selected low-flow statistics and for determining annual flow-duration statistics for Ohio streams. Regression techniques were used to develop equations for estimating 10-year recurrence-interval (10-percent annual-nonexceedance probability) low-flow yields, in cubic feet per second per square mile, with averaging periods of 1, 7, 30, and 90-day(s), and for estimating the yield corresponding to the long-term 80-percent duration flow. These equations, which estimate low-flow yields as a function of a streamflow-variability index, are based on previously published low-flow statistics for 79 long-term continuous-record streamgages with at least 10 years of data collected through water year 1997. When applied to the calibration dataset, average absolute percent errors for the regression equations ranged from 15.8 to 42.0 percent. The regression results have been incorporated into the U.S. Geological Survey (USGS) StreamStats application for Ohio (http://water.usgs.gov/osw/streamstats/ohio.html) in the form of a yield grid to facilitate estimation of the corresponding streamflow statistics in cubic feet per second. Logistic-regression equations also were developed and incorporated into the USGS StreamStats application for Ohio for selected low-flow statistics to help identify occurrences of zero-valued statistics. Quantiles of daily and 7-day mean streamflows were determined for annual and annual-seasonal (September–November) periods for each complete climatic year of streamflow-gaging station record for 110 selected streamflow-gaging stations with 20 or more years of record. The quantiles determined for each climatic year were the 99-, 98-, 95-, 90-, 80-, 75-, 70-, 60-, 50-, 40-, 30-, 25-, 20-, 10-, 5-, 2-, and 1-percent exceedance streamflows. Selected exceedance percentiles of the annual-exceedance percentiles were subsequently computed and tabulated to help facilitate consideration of the annual risk of exceedance or nonexceedance of annual and annual-seasonal-period flow-duration values. The quantiles are based on streamflow data collected through climatic year 2008.

Potential effects of landscape change on water supplies in the presence of reservoir storage

NASA Astrophysics Data System (ADS)

Guswa, Andrew J.; Hamel, Perrine; Dennedy-Frank, P. James

2017-04-01

This work presents a set of methods to evaluate the potential effects of landscape changes on water supplies. Potential impacts are a function of the seasonality of precipitation, losses of water to evapotranspiration and deep recharge, the flow-regulating ability of watersheds, and the availability of reservoir storage. For a given reservoir capacity, simple reservoir simulations with daily precipitation and streamflow enable the determination of the maximum steady supply of water for both the existing watershed and a hypothetical counter-factual that has neither flow-regulating benefits nor any losses. These two supply values, representing land use end-members, create an envelope that defines the water-supply service and bounds the effect of landscape change on water supply. These bounds can be used to discriminate between water supplies that may be vulnerable to landscape change and those that are unlikely to be affected. Two indices of the water-supply service exhibit substantial variability across 593 watersheds in the continental United States. Rcross, the reservoir capacity at which landscape change is unlikely to have any detrimental effect on water supply has an interquartile range of 0.14-4% of mean-annual-streamflow. Steep, forested watersheds with seasonal climates tend to have greater service values, and the indices of water-supply service are positively correlated with runoff ratios during the months with lowest flows.

Statistical summaries of New Jersey streamflow records

USGS Publications Warehouse

Laskowski, Stanley L.

1970-01-01

In 1961 the U.S. Geological Survey prepared a report which was published by the State of New Jersey as Water Resources Circular 6, "New Jersey Streamflow Records analyzed with Electronic Computer" by Miller and McCall. Basic discharge data for periods of record through 1958 were analyzed for 59 stream-gaging stations in New Jersey and flow-duration, low-flow, and high-flow tables were presented.The purpose of the current report is to update and expand Circular 6 by presenting, with a few meaningful statistics and tables, the bulk of the information that may be obtained from the mass of streamflow records available. The records for 79 of approximately 110 stream-gaging stations presently or previously operated in New Jersey, plus records for three stations in Pennsylvania, and one in New York are presented in summarized form. In addition to inclusing a great number of stations in this report, more years of record and more tables are listed for each station. A description of the station, three arrangements of data summarizing the daily flow records and one table listing statistics of the monthly mean flows are provided. No data representing instantaneous extreme flows are given. Plotting positions for the three types of curves describing the characteristics of daily discharge are listed for each station. Statistical parameters are also presented so that alternate curves may be drawn.All stations included in this report have 5 or more years of record. The data presented herein are based on observed flow past the gaging station. For any station where the observed flow is affected by regulation or diversion, a "Remarks" paragraph, explaining the possible effect on the data, is included in the station description.Since any streamflow record is a sample in time, the data derived from these records can provide only a guide to expected future flows. For this reason the flow records are analyzed by statistical techniques, and the magnitude of sampling errors should be recognized.These analyzed data will be useful to a large number of municipal, state, and federal agencies, industries, utilities, engineers, and hydrologists concerned with the availability, conservation, control, and use of surface waters. The tabulated data and curves illustrated herein can be used to select sites for water supplies, to determine flood or drought storage requirements, and to appraise the adequacy of flows for dilution of wastes or generation of power. The statistical values presented herein can be used in computer programs available in many universities, Federal and State agencies, and engineering firms for a broad spectrum of research and other studies.

Noninvasive parametric blood flow imaging of head and neck tumours using [15O]H2O and PET/CT.

PubMed

Komar, Gaber; Oikonen, Vesa; Sipilä, Hannu; Seppänen, Marko; Minn, Heikki

2012-11-01

The aim of this study was to develop a simple noninvasive method for measuring blood flow using [15O]H2O PET/CT for the head and neck area applicable in daily clinical practice. Fifteen dynamic [15O]H2O PET emission scans with simultaneous online radioactivity measurements of radial arterial blood [Blood-input functions (IFs)] were performed. Two noninvasively obtained population-based input functions were calculated by averaging all Blood-IF curves corrected for patients' body mass and injected dose [standardized uptake value (SUV)-IF] and for body surface area (BSA-IF) and injected dose. Parametric perfusion images were calculated for each set of IFs using a linearized two-compartment model, and values for several tissues were compared using Blood-IF as the gold standard. On comparing all tissues, the correlation between blood flow obtained with the invasive Blood-IF and both SUV-IF and BSA-IF was significant (R2=0.785 with P<0.001 and R2=0.813 with P<0.001, respectively). In individual tissues, the performance of the two noninvasive methods was most reliable in resting muscle and slightly less reliable in tumour and cerebellar regions. In these two tissues, only BSA-IF showed a significant correlation with Blood-IF (R2=0.307 with P=0.032 in tumours and R2=0.398 with P<0.007 in the cerebellum). The BSA-based noninvasive method enables clinically relevant delineation between areas of low and high blood flow in tumours. The blood flow of low-perfusion tissues can be reliably quantified using either of the evaluated noninvasive methods.

Changes in skin blood flow during the menstrual cycle: the influence of the menstrual cycle on the peripheral circulation in healthy female volunteers.

PubMed

Bartelink, M L; Wollersheim, H; Theeuwes, A; van Duren, D; Thien, T

1990-05-01

1. It is known that females have a lower skin perfusion than males. In women there are also differences in blood flow at different reproductive stages of their lives. As an initial investigation of the possible contribution of sex hormones to these differences, we studied skin and forearm blood flow during the natural changes in hormone levels which occur during the menstrual cycle. 2. Thirty-one healthy female volunteers were studied. The effect of a standardized finger cooling test (immersion of a gloved hand in a 16 degrees C water bath) on finger skin temperature and on laser Doppler flux in the finger, and forearm blood flow (strain gauge venous occlusion plethysmography) was assessed at four different times during one cycle: during menstruation, 1 day before ovulation, 2 days after ovulation and at the mid-luteal phase. Test days were determined by daily measurements of basal body temperature and were confirmed afterwards by determinations of serum luteinizing hormone, follicle-stimulating hormone, 17 beta-oestradiol and progesterone. 3. Peripheral skin circulation varied significantly within one menstrual cycle. The extremes were a mean finger skin temperature of 25.9 +/- 3.0 degrees C in the luteal phase compared with 28.4 +/- 3.7 degrees C in the pre-ovulatory phase (P = 0.002). The respective values for the mean laser Doppler flux were 18.4 +/- 10.9 compared with 29.2 +/- 16.4 arbitrary units (P = 0.003). 4. Baseline forearm muscle blood flow also varied significantly (P = 0.04) within one menstrual cycle, with low values in the menstrual phase compared with the other phases.(ABSTRACT TRUNCATED AT 250 WORDS)

Climate Informed Low Flow Frequency Analysis Using Nonstationary Modeling

NASA Astrophysics Data System (ADS)

Liu, D.; Guo, S.; Lian, Y.

2014-12-01

Stationarity is often assumed for frequency analysis of low flows in water resources management and planning. However, many studies have shown that flow characteristics, particularly the frequency spectrum of extreme hydrologic events,were modified by climate change and human activities and the conventional frequency analysis without considering the non-stationary characteristics may lead to costly design. The analysis presented in this paper was based on the more than 100 years of daily flow data from the Yichang gaging station 44 kilometers downstream of the Three Gorges Dam. The Mann-Kendall trend test under the scaling hypothesis showed that the annual low flows had significant monotonic trend, whereas an abrupt change point was identified in 1936 by the Pettitt test. The climate informed low flow frequency analysis and the divided and combined method are employed to account for the impacts from related climate variables and the nonstationarities in annual low flows. Without prior knowledge of the probability density function for the gaging station, six distribution functions including the Generalized Extreme Values (GEV), Pearson Type III, Gumbel, Gamma, Lognormal, and Weibull distributions have been tested to find the best fit, in which the local likelihood method is used to estimate the parameters. Analyses show that GEV had the best fit for the observed low flows. This study has also shown that the climate informed low flow frequency analysis is able to exploit the link between climate indices and low flows, which would account for the dynamic feature for reservoir management and provide more accurate and reliable designs for infrastructure and water supply.

Progress report on daily flow-routing simulation for the Carson River, California and Nevada

USGS Publications Warehouse

Hess, G.W.

1996-01-01

A physically based flow-routing model using Hydrological Simulation Program-FORTRAN (HSPF) was constructed for modeling streamflow in the Carson River at daily time intervals as part of the Truckee-Carson Program of the U.S. Geological Survey (USGS). Daily streamflow data for water years 1978-92 for the mainstem river, tributaries, and irrigation ditches from the East Fork Carson River near Markleeville and West Fork Carson River at Woodfords down to the mainstem Carson River at Fort Churchill upstream from Lahontan Reservoir were obtained from several agencies and were compiled into a comprehensive data base. No previous physically based flow-routing model of the Carson River has incorporated multi-agency streamflow data into a single data base and simulated flow at a daily time interval. Where streamflow data were unavailable or incomplete, hydrologic techniques were used to estimate some flows. For modeling purposes, the Carson River was divided into six segments, which correspond to those used in the Alpine Decree that governs water rights along the river. Hydraulic characteristics were defined for 48 individual stream reaches based on cross-sectional survey data obtained from field surveys and previous studies. Simulation results from the model were compared with available observed and estimated streamflow data. Model testing demonstrated that hydraulic characteristics of the Carson River are adequately represented in the models for a range of flow regimes. Differences between simulated and observed streamflow result mostly from inadequate data characterizing inflow and outflow from the river. Because irrigation return flows are largely unknown, irrigation return flow percentages were used as a calibration parameter to minimize differences between observed and simulated streamflows. Observed and simulated streamflow were compared for daily periods for the full modeled length of the Carson River and for two major subreaches modeled with more detailed input data. Hydrographs and statistics presented in this report describe these differences. A sensitivity analysis of four estimated components of the hydrologic system evaluated which components were significant in the model. Estimated ungaged tributary streamflow is not a significant component of the model during low runoff, but is significant during high runoff. The sensitivity analysis indicates that changes in the estimated irrigation diversion and estimated return flow creates a noticeable change in the statistics. The modeling for this study is preliminary. Results of the model are constrained by current availability and accuracy of observed hydrologic data. Several inflows and outflows of the Carson River are not described by time-series data and therefore are not represented in the model.

Simulated Water-Management Alternatives Using the Modular Modeling System for the Methow River Basin, Washington

USGS Publications Warehouse

Konrad, Christopher P.

2004-01-01

A precipitation-runoff model for the Methow River Basin was used to simulate six alternatives: (1) baseline of current flow, (2) line irrigation canals to limit seepage losses, (3) increase surface-water diversions through unlined canals for aquifer recharge, (4) convert from surface-water to ground-water resources to supply water for irrigation, and (5) reduce tree density in forested headwater catchments, and (6) natural flow. Daily streamflow from October 1, 1959, to September 30, 2001 (water years 1960?2001) was simulated. Lining irrigation canals (alternative 2) increased flows in the Chewuch, Twisp, and the Methow (upstream and at Twisp) Rivers during September because of lower diversion rates, but not in the Methow River near Pateros. Increasing diversions for aquifer recharge (alternative 3) increased streamflow from September into January, but reduced streamflow earlier in the summer. Conversion of surface-water diversions to ground-water wells (alternative 4) resulted in the largest increase in September streamflow of any alternative, but also marginally lower January flows (at most -8 percent in the 90-percent exceedence value). Forest-cover reduction (alternative 5) produced large increases in streamflow during high-flow periods in May and June and earlier onset of high flows and small increases in January streamflows. September streamflows were largely unaffected by alternative 5. Natural streamflow (alternative 6) was higher in September and lower in January than the baseline alternative.

Effects of coal mining on the water resources of the Tradewater River Basin, Kentucky

USGS Publications Warehouse

Grubb, Hayes F.; Ryder, Paul D.

1973-01-01

The effects of coal-mine drainage on the water resources of the Tradewater River basin, in the Western Coal Field region of Kentucky, were evaluated (1) by synthesis and interpretation of 16 years of daily conductance data. 465 chemical analyses covering an 18-year period, 28 years of daily discharge data, and 14 years of daily suspended-sediment data from the Tradewater River at Olney and (2) by collection, synthesis, and interpretation of chemical and physical water-quality data and water-quantity data collected over a 2-year period from mined and nonmined sites in the basin. Maximum observed values of 13 chemical and physical water-quality parameters were three to 300 times greater in the discharge from mined subbasins than in the discharge from nonmined subbasins. Potassium, chloride, and nitrate concentrations were not significantly different between mined and nonmined areas. Mean sulfate loads carried by the Tradewater River at Olney were about 75 percent greater for the period 1955-67 than for the period 1952-54. Suspended-sediment loads at Olney for the November-April storm-runoff periods generally vary in response to strip-mine coal production in the basin above Olney. Streamflow is maintained during extended dry periods in mined subbasins after streams in nonmined subbasins have ceased flowing. Some possible methods of reducing the effects of mine drainage on the streams are considered in view of a geochemical model proposed by Ivan Barnes and F. E. Clarke. Use of low-flow-augmenting reservoirs and crushed limestone in streambeds in nonmined areas seems to be the most promising method for alleviating effects of mine drainage at the present time. Other aspects of the water resources such as variability of water quantity and water quality in the basin are discussed briefly.

Long-term flow forecasts based on climate and hydrologic modeling: Uruguay River basin

NASA Astrophysics Data System (ADS)

Tucci, Carlos Eduardo Morelli; Clarke, Robin Thomas; Collischonn, Walter; da Silva Dias, Pedro Leite; de Oliveira, Gilvan Sampaio

2003-07-01

This paper describes a procedure for predicting seasonal flow in the Rio Uruguay drainage basin (area 75,000 km2, lying in Brazilian territory), using sequences of future daily rainfall given by the global climate model (GCM) of the Brazilian agency for climate prediction (Centro de Previsão de Tempo e Clima, or CPTEC). Sequences of future daily rainfall given by this model were used as input to a rainfall-runoff model appropriate for large drainage basins. Forecasts of flow in the Rio Uruguay were made for the period 1995-2001 of the full record, which began in 1940. Analysis showed that GCM forecasts underestimated rainfall over almost all the basin, particularly in winter, although interannual variability in regional rainfall was reproduced relatively well. A statistical procedure was used to correct for the underestimation of rainfall. When the corrected rainfall sequences were transformed to flow by the hydrologic model, forecasts of flow in the Rio Uruguay basin were better than forecasts based on historic mean or median flows by 37% for monthly flows and by 54% for 3-monthly flows.

Effects of the Temporal Variability of Evapotranspiration on Hydrologic Simulation in Central Florida

USGS Publications Warehouse

O'Reilly, Andrew M.

2007-01-01

The transient response of a hydrologic system can be of concern to water-resource managers, because it is often extreme relatively short-lived events, such as floods or droughts, that profoundly influence the management of the resource. The water available to a hydrologic system for stream flow and aquifer recharge is determined by the difference of precipitation and evapotranspiration (ET). As such, temporal variations in precipitation and ET determine the degree of influence each has on the transient response of the hydrologic system. Meteorological, ET, and hydrologic data collected from 1993 to 2003 and spanning 1- to 3 2/3 -year periods were used to develop a hydrologic model for each of five sites in central Florida. The sensitivities of simulated water levels and flows to simple approximations of ET were quantified and the adequacy of each ET approximation was assessed. ET was approximated by computing potential ET, using the Hargreaves and Priestley-Taylor equations, and applying vegetation coefficients to adjust the potential ET values to actual ET. The Hargreaves and Priestley-Taylor ET approximations were used in the calibrated hydrologic models while leaving all other model characteristics and parameter values unchanged. Two primary factors that influence how the temporal variability of ET affects hydrologic simulation in central Florida were identified: (1) stochastic character of precipitation and ET and (2) the ability of the local hydrologic system to attenuate variability in input stresses. Differences in the stochastic character of precipitation and ET, both the central location and spread of the data, result in substantial influence of precipitation on the quantity and timing of water available to the hydrologic system and a relatively small influence of ET. The temporal variability of ET was considerably less than that of precipitation at each site over a wide range of time scales (from daily to annual). However, when precipitation and ET are of similar magnitude, small errors in ET can produce relatively large errors in available water, and accurate estimates of actual ET are more important. Local hydrologic conditions can also be an important factor influencing the hydrologic response to ET variability. Various points along a flow path in a hydrologic system respond differently to temporal variations in ET. For example, soil moisture contents in the root zone are sensitive to daily variations in ET, whereas spring flow responds to only longer term variations in ET. Both the Hargreaves and Priestley-Taylor equations for potential ET, when applied with an annually invariant monthly vegetation coefficient derived from comparison of measured ET with computed potential ET values, can be used with a hydrologic model to produce reasonable predictions of water levels and flows. Baseline-adjusted modified coefficients of efficiency for simulated water levels ranged from 0.0, indicating that water levels were simulated equally as well with approximated ET as with actual ET values, to -0.6, indicating that water levels were simulated better with actual ET values. Simulations using the Hargreaves approximation consistently yielded larger absolute and relative errors than the Priestley-Taylor approximation. However, the differences between the Hargreaves and Priestley-Taylor simulations generally were much smaller than differences between these simulations and the simulations using actual ET. This suggests that the simpler Hargreaves equation may be an adequate substitute for the more complex Priestley-Taylor equation, depending on the level of accuracy required to satisfy the particular modeling objectives.

Experimental palatal candidosis and saliva flow in monkeys.

PubMed

Olsen, I; Haanaes, H R

1977-01-01

Maxillary acrylic plates, inoculated with Candida albicans, were inserted for 3 weeks in 10 monkeys (Cercopithecus aethiops) (Series I), and reinserted in five of the animals 8 weeks after removal (Series II). To suppress saliva flow oxyphencyclimine was injected intramuscularly (0.125 mg/kg) thrice daily for 3 weeks in six monkeys of Series I, while four controls received no drug. In Series II the oxyphencyclimine dose was doubled in three animals, and two controls were sham-treated with sodium chloride. Mean saliva flow was reduced to 58% after 1 week and to 63% after 3 weeks with the low dose of oxyphencyclimine. The values with the high dose were 56% and 64%, respectively. After 1 week thrush had developed beneath the plates of all monkeys. The patches were more extensive and regressed slower with oxyphencyclimine. Enlarged lesions were seen with the double dose. In Series I intraepithelial invasion by hyphae was detected more frequently and longer after inoculation in the oxyphencyclimine group. Such invasion was not found in biopsies from Series II. It is likely that saliva offers some protection against yeasts colonizing the fitting size of a denture.

Examining diel patterns of soil and xylem moisture using electrical resistivity imaging

NASA Astrophysics Data System (ADS)

Mares, Rachel; Barnard, Holly R.; Mao, Deqiang; Revil, André; Singha, Kamini

2016-05-01

The feedbacks among forest transpiration, soil moisture, and subsurface flowpaths are poorly understood. We investigate how soil moisture is affected by daily transpiration using time-lapse electrical resistivity imaging (ERI) on a highly instrumented ponderosa pine and the surrounding soil throughout the growing season. By comparing sap flow measurements to the ERI data, we find that periods of high sap flow within the diel cycle are aligned with decreases in ground electrical conductivity and soil moisture due to drying of the soil during moisture uptake. As sap flow decreases during the night, the ground conductivity increases as the soil moisture is replenished. The mean and variance of the ground conductivity decreases into the summer dry season, indicating drier soil and smaller diel fluctuations in soil moisture as the summer progresses. Sap flow did not significantly decrease through the summer suggesting use of a water source deeper than 60 cm to maintain transpiration during times of shallow soil moisture depletion. ERI captured spatiotemporal variability of soil moisture on daily and seasonal timescales. ERI data on the tree showed a diel cycle of conductivity, interpreted as changes in water content due to transpiration, but changes in sap flow throughout the season could not be interpreted from ERI inversions alone due to daily temperature changes.

Assessment of catchments' flooding potential: a physically-based analytical tool

NASA Astrophysics Data System (ADS)

Botter, G.; Basso, S.; Schirmer, M.

2016-12-01

The assessment of the flooding potential of river catchments is critical in many research and applied fields, ranging from river science and geomorphology to urban planning and the insurance industry. Predicting magnitude and frequency of floods is key to prevent and mitigate the negative effects of high flows, and has therefore long been the focus of hydrologic research. Here, the recurrence intervals of seasonal flow maxima are estimated through a novel physically-based analytic approach, which links the extremal distribution of streamflows to the stochastic dynamics of daily discharge. An analytical expression of the seasonal flood-frequency curve is provided, whose parameters embody climate and landscape attributes of the contributing catchment and can be estimated from daily rainfall and streamflow data. Only one parameter, which expresses catchment saturation prior to rainfall events, needs to be calibrated on the observed maxima. The method has been tested in a set of catchments featuring heterogeneous daily flow regimes. The model is able to reproduce characteristic shapes of flood-frequency curves emerging in erratic and persistent flow regimes and provides good estimates of seasonal flow maxima in different climatic regions. Performances are steady when the magnitude of events with return times longer than the available sample size is estimated. This makes the approach especially valuable for regions affected by data scarcity.

Streamflow characteristics for selected stations in and near the Grand Mesa, Uncompahgre, and Gunnison National Forests, southwestern Colorado

USGS Publications Warehouse

Kuhn, Gerhard

2002-01-01

The U.S Geological Survey, in cooperation with the Grand Mesa, Uncompahgre, and Gunnison National Forests, began a study in 2000 to develop selected streamflow characteristics for 60 streamflow-gaging stations in and near the Grand Mesa, Uncompahgre, and Gunnison National Forests. The study area is located in southwestern Colorado within the Gunnison River, Dolores River, and Plateau Creek Basins, which are tributaries of the Colorado River. In addition to presenting the compiled daily, monthly, and annual discharge data for the 60 stations, the report presents tabular and graphical results for the following computed streamflow characteristics: (1) Instantaneous peak-flow frequency; (2) flow duration for daily mean discharges on an annual (water year) basis and on a monthly basis, and flow duration for the annual and monthly mean discharges; (3) low-flow and high-flow frequency of daily mean discharges for periods of 1, 3, 7, 15, 30, 60, 120, and 183 consecutive days; and (4) annual and monthly mean and median discharges for each year and month of record, and frequency of the annual and monthly mean and median discharges. All discharge data and results from the streamflow-characteristics analyses are presented in Microsoft Excel workbooks on the enclosed CD-ROM.

Hour-Glass Neural Network Based Daily Money Flow Estimation for Automatic Teller Machines

NASA Astrophysics Data System (ADS)

Karungaru, Stephen; Akashi, Takuya; Nakano, Miyoko; Fukumi, Minoru

Monetary transactions using Automated Teller Machines (ATMs) have become a normal part of our daily lives. At ATMs, one can withdraw, send or debit money and even update passbooks among many other possible functions. ATMs are turning the banking sector into a ubiquitous service. However, while the advantages for the ATM users (financial institution customers) are many, the financial institution side faces an uphill task in management and maintaining the cash flow in the ATMs. On one hand, too much money in a rarely used ATM is wasteful, while on the other, insufficient amounts would adversely affect the customers and may result in a lost business opportunity for the financial institution. Therefore, in this paper, we propose a daily cash flow estimation system using neural networks that enables better daily forecasting of the money required at the ATMs. The neural network used in this work is a five layered hour glass shaped structure that achieves fast learning, even for the time series data for which seasonality and trend feature extraction is difficult. Feature extraction is carried out using the Akamatsu Integral and Differential transforms. This work achieves an average estimation accuracy of 92.6%.

Quality of experience in real and virtual environments: some suggestions for the development of positive technologies.

PubMed

Gaggioli, Andrea

2012-01-01

What does one feel when one uses virtual reality? How does this experience differ from the experience associated with "real life" activities and situations? To answer these questions, we used the Experience Sampling Method (ESM), a procedure that allows researchers to investigate the daily fluctuations in the quality of experience through on-line self reports that participants fill out during daily life. The investigation consisted in one-week ESM observation (N = 42). During this week, participants underwent two virtual reality sessions: Immediately after the exposure to virtual environments, they were asked to complete a ESM report. For data analysis, experiential variables were aggregated into four dimensions: Mood, Engagement, Confidence, and Intrinsic Motivation Intrinsic Motivation. Findings showed that virtual experience is characterized by a specific configuration, which comprises significantly positive values for affective and cognitive components. In particular, positive scores of Mood suggest that participants perceived VR as an intrinsically pleasurable activity, while positive values of Engagement indicate that the use of VR and the experimental task provided valid opportunities for action and high skill investment. Furthermore, results showed that virtual experience is associated with Flow, a state of consciousness characterized by narrowed focus of attention, deep concentration, positive affect and intrinsic reward. Implications for VR research and practice are discussed.

Future Flows Hydrology: an ensemble of daily river flow and monthly groundwater levels for use for climate change impact assessment across Great Britain

NASA Astrophysics Data System (ADS)

Prudhomme, C.; Haxton, T.; Crooks, S.; Jackson, C.; Barkwith, A.; Williamson, J.; Kelvin, J.; Mackay, J.; Wang, L.; Young, A.; Watts, G.

2012-12-01

The dataset Future Flows Hydrology was developed as part of the project "Future Flows and Groundwater Levels" to provide a consistent set of transient daily river flow and monthly groundwater levels projections across England, Wales and Scotland to enable the investigation of the role of climate variability on river flow and groundwater levels nationally and how this may change in the future. Future Flows Hydrology is derived from Future Flows Climate, a national ensemble projection derived from the Hadley Centre's ensemble projection HadRM3-PPE to provide a consistent set of climate change projections for the whole of Great Britain at both space and time resolutions appropriate for hydrological applications. Three hydrological models and one groundwater level model were used to derive Future Flows Hydrology, with 30 river sites simulated by two hydrological models to enable assessment of hydrological modelling uncertainty in studying the impact of climate change on the hydrology. Future Flows Hydrology contains an 11-member ensemble of transient projections from January 1951 to December 2098, each associated with a single realisation from a different variant of HadRM3 and a single hydrological model. Daily river flows are provided for 281 river catchments and monthly groundwater levels at 24 boreholes as .csv files containing all 11 ensemble members. When separate simulations are done with two hydrological models, two separate .csv files are provided. Because of potential biases in the climate-hydrology modelling chain, catchment fact sheets are associated with each ensemble. These contain information on the uncertainty associated with the hydrological modelling when driven using observed climate and Future Flows Climate for a period representative of the reference time slice 1961-1990 as described by key hydrological statistics. Graphs of projected changes for selected hydrological indicators are also provided for the 2050s time slice. Limitations associated with the dataset are provided, along with practical recommendation of use. Future Flows Hydrology is freely available for non-commercial use under certain licensing conditions. For each study site, catchment averages of daily precipitation and monthly potential evapotranspiration, used to drive the hydrological models, are made available, so that hydrological modelling uncertainty under climate change conditions can be explored further. doi:10.5285/f3723162-4fed-4d9d-92c6-dd17412fa37b.

Future Flows Hydrology: an ensemble of daily river flow and monthly groundwater levels for use for climate change impact assessment across Great Britain

NASA Astrophysics Data System (ADS)

Prudhomme, C.; Haxton, T.; Crooks, S.; Jackson, C.; Barkwith, A.; Williamson, J.; Kelvin, J.; Mackay, J.; Wang, L.; Young, A.; Watts, G.

2013-03-01

The dataset Future Flows Hydrology was developed as part of the project "Future Flows and Groundwater Levels'' to provide a consistent set of transient daily river flow and monthly groundwater level projections across England, Wales and Scotland to enable the investigation of the role of climate variability on river flow and groundwater levels nationally and how this may change in the future. Future Flows Hydrology is derived from Future Flows Climate, a national ensemble projection derived from the Hadley Centre's ensemble projection HadRM3-PPE to provide a consistent set of climate change projections for the whole of Great Britain at both space and time resolutions appropriate for hydrological applications. Three hydrological models and one groundwater level model were used to derive Future Flows Hydrology, with 30 river sites simulated by two hydrological models to enable assessment of hydrological modelling uncertainty in studying the impact of climate change on the hydrology. Future Flows Hydrology contains an 11-member ensemble of transient projections from January 1951 to December 2098, each associated with a single realisation from a different variant of HadRM3 and a single hydrological model. Daily river flows are provided for 281 river catchments and monthly groundwater levels at 24 boreholes as .csv files containing all 11 ensemble members. When separate simulations are done with two hydrological models, two separate .csv files are provided. Because of potential biases in the climate-hydrology modelling chain, catchment fact sheets are associated with each ensemble. These contain information on the uncertainty associated with the hydrological modelling when driven using observed climate and Future Flows Climate for a period representative of the reference time slice 1961-1990 as described by key hydrological statistics. Graphs of projected changes for selected hydrological indicators are also provided for the 2050s time slice. Limitations associated with the dataset are provided, along with practical recommendation of use. Future Flows Hydrology is freely available for non-commercial use under certain licensing conditions. For each study site, catchment averages of daily precipitation and monthly potential evapotranspiration, used to drive the hydrological models, are made available, so that hydrological modelling uncertainty under climate change conditions can be explored further. doi:10.5285/f3723162-4fed-4d9d-92c6-dd17412fa37b

Analysis of the solar radiation data for Beer Sheva, Israel, and its environs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kudish, A.I.; Ianetz, A.

The solar radiation climate of Beer Sheva, Israel, is reported upon in detail. The database utilized in this analysis consisted of global radiation on a horizontal surface, normal incidence beam radiation, and global radiation on a south-facing surface tilted at 40{degree}. Monthly-average hourly and daily values are reported for each of these three types of measured radiations, together with the calculated monthly-average daily values for the components of the global radiation, viz. the horizontal beam and diffuse radiations. The monthly-average hourly and daily clearness index values have also been calculated and analyzed. Monthly-average daily frequency distributions of the clearness indexmore » values are reported for each month. The solar radiation climate of Beer Sheva has also been compared to those reported for a number of countries in this region. The annual-average daily global radiation incident on a horizontal surface is 18.91 MG/m{sup 2} and that for normal incidence beam radiation is 21.17 MG/m{sup 2}. The annual-average daily fraction of the horizontal global radiation that is beam is 0.72. The annual-average daily value for the clearness index is 0.587 and the average frequency of clear days annually is 58.6%. The authors conclude, based upon the above analysis, that Beer Sheva and its environs are characterized by relatively high, average-daily irradiation rates, both global and beam, and a relatively high frequency of clear days.« less

A Statistical Model-Based Decision Support System for Managing Summer Stream Temperatures with Quantified Confidence Analysis

NASA Astrophysics Data System (ADS)

Neumann, D. W.; Zagona, E. A.; Rajagopalan, B.

2005-12-01

Warm summer stream temperatures due to low flows and high air temperatures are a critical water quality problem in many western U.S. river basins because they impact threatened fish species' habitat. Releases from storage reservoirs and river diversions are typically driven by human demands such as irrigation, municipal and industrial uses and hydropower production. Historically, fish needs have not been formally incorporated in the operating procedures, which do not supply adequate flows for fish in the warmest, driest periods. One way to address this problem is for local and federal organizations to purchase water rights to be used to increase flows, hence decrease temperatures. A statistical model-predictive technique for efficient and effective use of a limited supply of fish water has been developed and incorporated in a Decision Support System (DSS) that can be used in an operations mode to effectively use water acquired to mitigate warm stream temperatures. The DSS is a rule-based system that uses the empirical, statistical predictive model to predict maximum daily stream temperatures based on flows that meet the non-fish operating criteria, and to compute reservoir releases of allocated fish water when predicted temperatures exceed fish habitat temperature targets with a user specified confidence of the temperature predictions. The empirical model is developed using a step-wise linear regression procedure to select significant predictors, and includes the computation of a prediction confidence interval to quantify the uncertainty of the prediction. The DSS also includes a strategy for managing a limited amount of water throughout the season based on degree-days in which temperatures are allowed to exceed the preferred targets for a limited number of days that can be tolerated by the fish. The DSS is demonstrated by an example application to the Truckee River near Reno, Nevada using historical flows from 1988 through 1994. In this case, the statistical model predicts maximum daily Truckee River stream temperatures in June, July, and August using predicted maximum daily air temperature and modeled average daily flow. The empirical relationship was created using a step-wise linear regression selection process using 1993 and 1994 data. The adjusted R2 value for this relationship is 0.91. The model is validated using historic data and demonstrated in a predictive mode with a prediction confidence interval to quantify the uncertainty. Results indicate that the DSS could substantially reduce the number of target temperature violations, i.e., stream temperatures exceeding the target temperature levels detrimental to fish habitat. The results show that large volumes of water are necessary to meet a temperature target with a high degree of certainty and violations may still occur if all of the stored water is depleted. A lower degree of certainty requires less water but there is a higher probability that the temperature targets will be exceeded. Addition of the rules that consider degree-days resulted in a reduction of the number of temperature violations without increasing the amount of water used. This work is described in detail in publications referenced in the URL below.

[Effects of different irrigations on the water physiological characteristics of Haloxylon ammodendron in Taklimakan Desert hinterland].

PubMed

Xie, Ting-ting; Zhang, Xi-ming; Liang, Shao-min; Shan, Li-shan; Yang, Xiao-lin; Hua, Yong-hui

2008-04-01

By using heat-balance stem flow gauge and press chamber, the water physiological characteristics of Haloxylon ammodendron under different irrigations in Taklimakan Desert hinterland were measured and analyzed. The results indicated that the diurnal variation curve of H. ammodendron stem sap flow varied with irrigations. When irrigated 35 and 24.5 kg x plant(-1) once time, the diurnal variation of stem sap flow changed in single peak curve and the variation extent was higher; while irrigated 14 kg x plant(-1) once time, the diurnal variation changed in two-peak curve and the variation extent was small. With the decrease of irrigations, the average daily sap flow rate and the daily water consumption of H. ammodendron decreased gradually, the dawn and postmeridian water potential also had a gradual decrease, and the correlations of stem sap flow with total radiation, air temperature, relative humidity, and wind speed enhanced. Under different irrigations, the correlation between stem sap flow rate and total radiation was always the best.

Comparison and evaluation of model structures for the simulation of pollution fluxes in a tile-drained river basin.

PubMed

Hoang, Linh; van Griensven, Ann; van der Keur, Peter; Refsgaard, Jens Christian; Troldborg, Lars; Nilsson, Bertel; Mynett, Arthur

2014-01-01

The European Union Water Framework Directive requires an integrated pollution prevention plan at the river basin level. Hydrological river basin modeling tools are therefore promising tools to support the quantification of pollution originating from different sources. A limited number of studies have reported on the use of these models to predict pollution fluxes in tile-drained basins. This study focused on evaluating different modeling tools and modeling concepts to quantify the flow and nitrate fluxes in the Odense River basin using DAISY-MIKE SHE (DMS) and the Soil and Water Assessment Tool (SWAT). The results show that SWAT accurately predicted flow for daily and monthly time steps, whereas simulation of nitrate fluxes were more accurate at a monthly time step. In comparison to the DMS model, which takes into account the uncertainty of soil hydraulic and slurry parameters, SWAT results for flow and nitrate fit well within the range of DMS simulated values in high-flow periods but were slightly lower in low-flow periods. Despite the similarities of simulated flow and nitrate fluxes at the basin outlet, the two models predicted very different separations into flow components (overland flow, tile drainage, and groundwater flow) as well as nitrate fluxes from flow components. It was concluded that the assessment on which the model provides a better representation of the reality in terms of flow paths should not only be based on standard statistical metrics for the entire river basin but also needs to consider additional data, field experiments, and opinions of field experts. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Evaluation of streamflow traveltime and streamflow gains and losses along the lower Purgatoire River, southeastern Colorado, 1984-92

USGS Publications Warehouse

Dash, R.G.; Edelmann, P.R.

1997-01-01

Traveltime and gains and losses within a stream are important basic characteristics of streamflow. The lower Purgatoire River flows more than 160 river miles from Trinidad to the Arkansas River near Las Animas. A better knowledge of streamflow traveltime and streamflow gains and losses along the lower Purgatoire River would enable more informed management decisions about the availability of water supplies for irrigation use in southeastern Colorado. In 1994-95, the U.S.\\x11Geological Survey, in cooperation with the Purgatoire River Water Conservancy District and the Arkansas River Compact Administration, evaluated streamflow traveltime and estimated streamflow gains and losses using historical surface-water records. Traveltime analyses were used along the lower Purgatoire River to determine when streamflows would arrive at selected downstream sites. The substantial effects of diversions for irrigation and unmeasured return flows in the most upstream reach of the river prevented the tracking of streamflow through reach\\x111. Therefore, the estimation of streamflow traveltime for the 60.6 miles of river downstream from Trinidad could not be made.Hourly streamflow data from 1990 through 1994 were used to estimate traveltimes of more than 30 streamflow events for about 100 miles of the lower Purgatoire River. In the middle reach of the river, the traveltime of streamflow for the 40.1\\x11miles ranged from about 11 to about 47\\x11hours, and in the lower reach of the river, traveltime for the 58.5 miles ranged from about 6 to about 61 hours.Traveltime in the river reaches generally increased as streamflow decreased, but also varied for a specific streamflow in both reaches. Streamflow gains and losses were estimated using daily streamflow data at the upstream and downstream sites, available tributary inflow data, and daily diversion data. Differences between surface-water inflows and surface-water outflows in a reach determined the quantity of water gained or lost. In the most upstream reach of the river near Trinidad, difficulties in establishing streamflow traveltimes prevented the estimation of streamflow gains or losses. From 1984 through 1992, more than 2,900 daily estimates of streamflow gains or losses were made for the last 100\\x11miles of the lower Purgatoire River that indicated daily gains and losses in streamflow were common during all four seasons of the year. Although some large daily streamflow gains and losses were computed, most daily estimates indicated small gains and losses in streamflow. The daily median streamflow gain or loss for the middle reach of the river was close to zero during every season, whereas median values for the lower most reach of the river indicated a daily gain in streamflow during every season.

Evaluation of statistical and rainfall-runoff models for predicting historical daily streamflow time series in the Des Moines and Iowa River watersheds

USGS Publications Warehouse

Farmer, William H.; Knight, Rodney R.; Eash, David A.; Kasey J. Hutchinson,; Linhart, S. Mike; Christiansen, Daniel E.; Archfield, Stacey A.; Over, Thomas M.; Kiang, Julie E.

2015-08-24

Daily records of streamflow are essential to understanding hydrologic systems and managing the interactions between human and natural systems. Many watersheds and locations lack streamgages to provide accurate and reliable records of daily streamflow. In such ungaged watersheds, statistical tools and rainfall-runoff models are used to estimate daily streamflow. Previous work compared 19 different techniques for predicting daily streamflow records in the southeastern United States. Here, five of the better-performing methods are compared in a different hydroclimatic region of the United States, in Iowa. The methods fall into three classes: (1) drainage-area ratio methods, (2) nonlinear spatial interpolations using flow duration curves, and (3) mechanistic rainfall-runoff models. The first two classes are each applied with nearest-neighbor and map-correlated index streamgages. Using a threefold validation and robust rank-based evaluation, the methods are assessed for overall goodness of fit of the hydrograph of daily streamflow, the ability to reproduce a daily, no-fail storage-yield curve, and the ability to reproduce key streamflow statistics. As in the Southeast study, a nonlinear spatial interpolation of daily streamflow using flow duration curves is found to be a method with the best predictive accuracy. Comparisons with previous work in Iowa show that the accuracy of mechanistic models with at-site calibration is substantially degraded in the ungaged framework.

Median and Low-Flow Characteristics for Streams under Natural and Diverted Conditions, Northeast Maui, Hawaii

USGS Publications Warehouse

Gingerich, Stephen B.

2005-01-01

Flow-duration statistics under natural (undiverted) and diverted flow conditions were estimated for gaged and ungaged sites on 21 streams in northeast Maui, Hawaii. The estimates were made using the optimal combination of continuous-record gaging-station data, low-flow measurements, and values determined from regression equations developed as part of this study. Estimated 50- and 95-percent flow duration statistics for streams are presented and the analyses done to develop and evaluate the methods used in estimating the statistics are described. Estimated streamflow statistics are presented for sites where various amounts of streamflow data are available as well as for locations where no data are available. Daily mean flows were used to determine flow-duration statistics for continuous-record stream-gaging stations in the study area following U.S. Geological Survey established standard methods. Duration discharges of 50- and 95-percent were determined from total flow and base flow for each continuous-record station. The index-station method was used to adjust all of the streamflow records to a common, long-term period. The gaging station on West Wailuaiki Stream (16518000) was chosen as the index station because of its record length (1914-2003) and favorable geographic location. Adjustments based on the index-station method resulted in decreases to the 50-percent duration total flow, 50-percent duration base flow, 95-percent duration total flow, and 95-percent duration base flow computed on the basis of short-term records that averaged 7, 3, 4, and 1 percent, respectively. For the drainage basin of each continuous-record gaged site and selected ungaged sites, morphometric, geologic, soil, and rainfall characteristics were quantified using Geographic Information System techniques. Regression equations relating the non-diverted streamflow statistics to basin characteristics of the gaged basins were developed using ordinary-least-squares regression analyses. Rainfall rate, maximum basin elevation, and the elongation ratio of the basin were the basin characteristics used in the final regression equations for 50-percent duration total flow and base flow. Rainfall rate and maximum basin elevation were used in the final regression equations for the 95-percent duration total flow and base flow. The relative errors between observed and estimated flows ranged from 10 to 20 percent for the 50-percent duration total flow and base flow, and from 29 to 56 percent for the 95-percent duration total flow and base flow. The regression equations developed for this study were used to determine the 50-percent duration total flow, 50-percent duration base flow, 95-percent duration total flow, and 95-percent duration base flow at selected ungaged diverted and undiverted sites. Estimated streamflow, prediction intervals, and standard errors were determined for 48 ungaged sites in the study area and for three gaged sites west of the study area. Relative errors were determined for sites where measured values of 95-percent duration discharge of total flow were available. East of Keanae Valley, the 95-percent duration discharge equation generally underestimated flow, and within and west of Keanae Valley, the equation generally overestimated flow. Reduction in 50- and 95-percent flow-duration values in stream reaches affected by diversions throughout the study area average 58 to 60 percent.

Trends in 1970-2010 southern California surface maximum temperatures: extremes and heat waves

NASA Astrophysics Data System (ADS)

Ghebreegziabher, Amanuel T.

Daily maximum temperatures from 1970-2010 were obtained from the National Climatic Data Center (NCDC) for 28 South Coast Air Basin (SoCAB) Cooperative Network (COOP) sites. Analyses were carried out on the entire data set, as well as on the 1970-1974 and 2006-2010 sub-periods, including construction of spatial distributions and time-series trends of both summer-average and annual-maximum values and of the frequency of two and four consecutive "daytime" heat wave events. Spatial patterns of average and extreme values showed three areas consistent with climatological SoCAB flow patterns: cold coastal, warm inland low-elevation, and cool further-inland mountain top. Difference (2006-2010 minus 1970-1974) distributions of both average and extreme-value trends were consistent with the shorter period (1970-2005) study of previous study, as they showed the expected inland regional warming and a "reverse-reaction" cooling in low elevation coastal and inland areas open to increasing sea breeze flows. Annual-extreme trends generally showed cooling at sites below 600 m and warming at higher elevations. As the warming trends of the extremes were larger than those of the averages, regional warming thus impacts extremes more than averages. Spatial distributions of hot-day frequencies showed expected maximum at inland low-elevation sites. Regional warming again thus induced increases at both elevated-coastal areas, but low-elevation areas showed reverse-reaction decreases.

A comparison of airborne evapotranspiration maps and sapflow measurements in oak and beech forest stands

NASA Astrophysics Data System (ADS)

Schlerf, M.; Mallick, K.; Hassler, S. K.; Blume, T.; Ronellenfitsch, F.; Gerhards, M.; Udelhoven, T.; Weiler, M.

2017-12-01

Accurate estimations of spatially explicit daily Evapotranspiration (ET) may help water managers quantifying the water requirements of agricultural crops or trees. Airborne remote sensing may provide suitable ET maps, but uncertainties need to be better understood. In this study we compared high spatial resolution remotely sensed ET maps for 7 July 2016 with sap flow measurements over 32 forest stands located in the Attert catchment, Luxembourg. Forest stands differed in terms of species (Quercus robur, Fagus sylvatica), geology (schist, marl, sandstone), and geomorphology (slope position, plain, valley). Within each plot, at 1-3 trees the sap flow velocity (cm per hour) was measured between 8 am and 8 pm in 10 min intervals and averaged into a single value per plot and converted into values of volume flux (litres per day). Remotely sensed ET maps were derived by integrating airborne thermal infrared (TIR) images with an analytical surface energy balance model, Surface Temperature Initiated Closure (STIC1.2, Mallick et al. 2016). Airborne TIR images were acquired under clear sky conditions at 9:12, 10:08, 13:56, 14:50, 15:54, and 18:41 local time using a hyperspectral-thermal instrument. Images were geometrically corrected, calibrated, mosaicked, and converted to surface radiometric temperature. Surface temperature maps in conjunction with meteorological measurements recorded in the forest plots (air temperature, global radiation, relative humidity) were used as input to STIC1.2, for simultaneously estimating ET, sensible heat flux as well as surface and aerodynamic conductances. Instantaneous maps of ET were converted into daily ET maps and compared with the sap flow measurements. Results reveal a significant correspondence between remote sensing and field measured ET. The differences in the magnitude of predicted versus observed ET was found to be associated the biophysical conductances, radiometric surface temperature, and ecohydrological characteristics of the underlying landscape. Forest plots reveal differences in ET depending on the underlying geology and the slope position. Airborne remote sensing offers new ways of estimating the diurnal course of plant transpiration over entire landscapes and is an important bridging technology before high resolution TIR sensors will come into space.

Daily Streamflow Predictions in an Ungauged Watershed in Northern California Using the Precipitation-Runoff Modeling System (PRMS): Calibration Challenges when nearby Gauged Watersheds are Hydrologically Dissimilar

NASA Astrophysics Data System (ADS)

Dhakal, A. S.; Adera, S.

2017-12-01

Accurate daily streamflow prediction in ungauged watersheds with sparse information is challenging. The ability of a hydrologic model calibrated using nearby gauged watersheds to predict streamflow accurately depends on hydrologic similarities between the gauged and ungauged watersheds. This study examines daily streamflow predictions using the Precipitation-Runoff Modeling System (PRMS) for the largely ungauged San Antonio Creek watershed, a 96 km2 sub-watershed of the Alameda Creek watershed in Northern California. The process-based PRMS model is being used to improve the accuracy of recent San Antonio Creek streamflow predictions generated by two empirical methods. Although San Antonio Creek watershed is largely ungauged, daily streamflow data exists for hydrologic years (HY) 1913 - 1930. PRMS was calibrated for HY 1913 - 1930 using streamflow data, modern-day land use and PRISM precipitation distribution, and gauged precipitation and temperature data from a nearby watershed. The PRMS model was then used to generate daily streamflows for HY 1996-2013, during which the watershed was ungauged, and hydrologic responses were compared to two nearby gauged sub-watersheds of Alameda Creek. Finally, the PRMS-predicted daily flows between HY 1996-2013 were compared to the two empirically-predicted streamflow time series: (1) the reservoir mass balance method and (2) correlation of historical streamflows from 80 - 100 years ago between San Antonio Creek and a nearby sub-watershed located in Alameda Creek. While the mass balance approach using reservoir storage and transfers is helpful for estimating inflows to the reservoir, large discrepancies in daily streamflow estimation can arise. Similarly, correlation-based predicted daily flows which rely on a relationship from flows collected 80-100 years ago may not represent current watershed hydrologic conditions. This study aims to develop a method of streamflow prediction in the San Antonio Creek watershed by examining PRMS's model outputs as well as empirically generated flow data for their use in water resources management decisions. PRMS is also being used to better understand the streamflow patterns in the San Antonio Creek watershed for a variety of antecedent soil moisture conditions as the creek is generally dry between late Spring and early Fall.

MicroDAIMON study: Microcirculatory DAIly MONitoring in critically ill patients: a prospective observational study.

PubMed

Scorcella, Claudia; Damiani, Elisa; Domizi, Roberta; Pierantozzi, Silvia; Tondi, Stefania; Carsetti, Andrea; Ciucani, Silvia; Monaldi, Valentina; Rogani, Mara; Marini, Benedetto; Adrario, Erica; Romano, Rocco; Ince, Can; Boerma, E Christiaan; Donati, Abele

2018-05-15

Until now, the prognostic value of microcirculatory alterations in critically ill patients has been mainly evaluated in highly selected subgroups. Aim of this study is to monitor the microcirculation daily in mixed group of Intensive Care Unit (ICU)-patients and to establish the association between (the evolution of) microcirculatory alterations and outcome. This is a prospective longitudinal observational single-centre study in adult patients admitted to a 12-bed ICU in an Italian teaching hospital. Sublingual microcirculation was evaluated daily, from admission to discharge/death, using Sidestream Dark Field imaging. Videos were analysed offline to assess flow and density variables. Laboratory and clinical data were recorded simultaneously. A priori, a Microvascular Flow Index (MFI) < 2.6 was defined as abnormal. A binary logistic regression analysis was performed to evaluate the association between microcirculatory variables and outcomes; a Kaplan-Meier survival curve was built. Outcomes were ICU and 90-day mortality. A total of 97 patients were included. An abnormal MFI was present on day 1 in 20.6%, and in 55.7% of cases during ICU admission. Patients with a baseline MFI < 2.6 had higher ICU, in-hospital and 90-day mortality (45 vs. 15.6%, p = 0.012; 55 vs. 28.6%, p = 0.035; 55 vs. 26%, p = 0.017, respectively). An independent association between baseline MFI < 2.6 and outcome was confirmed in a binary logistic analysis (odds ratio 4.594 [1.340-15.754], p = 0.015). A heart rate (HR) ≥ 90 bpm was an adjunctive predictor of mortality. However, a model with stepwise inclusion of mean arterial pressure < 65 mmHg, HR ≥ 90 bpm, lactate > 2 mmol/L and MFI < 2.6 did not detect significant differences in ICU mortality. In case an abnormal MFI was present on day 1, ICU mortality was significantly higher in comparison with patients with an abnormal MFI after day 1 (38 vs. 6%, p = 0.001), indicating a time-dependent significant difference in prognostic value. In a general ICU population, an abnormal microcirculation at baseline is an independent predictor for mortality. In this setting, additional routine daily microcirculatory monitoring did not reveal extra prognostic information. Further research is needed to integrate microcirculatory monitoring in a set of commonly available hemodynamic variables. Trial registration NCT 02649088, www.clinicaltrials.gov . Date of registration: 23 December 2015, retrospectively registered.

Independent technical review and analysis of hydraulic modeling and hydrology under low-flow conditions of the Des Plaines River near Riverside, Illinois

USGS Publications Warehouse

Over, Thomas M.; Straub, Timothy D.; Hortness, Jon E.; Murphy, Elizabeth A.

2012-01-01

The U.S. Geological Survey (USGS) has operated a streamgage and published daily flows for the Des Plaines River at Riverside since Oct. 1, 1943. A HEC-RAS model has been developed to estimate the effect of the removal of Hofmann Dam near the gage on low-flow elevations in the reach approximately 3 miles upstream from the dam. The Village of Riverside, the Illinois Department of Natural Resources-Office of Water Resources (IDNR-OWR), and the U. S. Army Corps of Engineers-Chicago District (USACE-Chicago) are interested in verifying the performance of the HEC-RAS model for specific low-flow conditions, and obtaining an estimate of selected daily flow quantiles and other low-flow statistics for a selected period of record that best represents current hydrologic conditions. Because the USGS publishes streamflow records for the Des Plaines River system and provides unbiased analyses of flows and stream hydraulic characteristics, the USGS served as an Independent Technical Reviewer (ITR) for this study.

Methods to estimate historical daily streamflow for ungaged stream locations in Minnesota

USGS Publications Warehouse

Lorenz, David L.; Ziegeweid, Jeffrey R.

2016-03-14

Effective and responsible management of water resources relies on a thorough understanding of the quantity and quality of available water; however, streamgages cannot be installed at every location where streamflow information is needed. Therefore, methods for estimating streamflow at ungaged stream locations need to be developed. This report presents a statewide study to develop methods to estimate the structure of historical daily streamflow at ungaged stream locations in Minnesota. Historical daily mean streamflow at ungaged locations in Minnesota can be estimated by transferring streamflow data at streamgages to the ungaged location using the QPPQ method. The QPPQ method uses flow-duration curves at an index streamgage, relying on the assumption that exceedance probabilities are equivalent between the index streamgage and the ungaged location, and estimates the flow at the ungaged location using the estimated flow-duration curve. Flow-duration curves at ungaged locations can be estimated using recently developed regression equations that have been incorporated into StreamStats (http://streamstats.usgs.gov/), which is a U.S. Geological Survey Web-based interactive mapping tool that can be used to obtain streamflow statistics, drainage-basin characteristics, and other information for user-selected locations on streams.

Simulation of streamflow in the McTier Creek watershed, South Carolina

USGS Publications Warehouse

Feaster, Toby D.; Golden, Heather E.; Odom, Kenneth R.; Lowery, Mark A.; Conrads, Paul; Bradley, Paul M.

2010-01-01

The McTier Creek watershed is located in the Sand Hills ecoregion of South Carolina and is a small catchment within the Edisto River Basin. Two watershed hydrology models were applied to the McTier Creek watershed as part of a larger scientific investigation to expand the understanding of relations among hydrologic, geochemical, and ecological processes that affect fish-tissue mercury concentrations within the Edisto River Basin. The two models are the topography-based hydrological model (TOPMODEL) and the grid-based mercury model (GBMM). TOPMODEL uses the variable-source area concept for simulating streamflow, and GBMM uses a spatially explicit modified curve-number approach for simulating streamflow. The hydrologic output from TOPMODEL can be used explicitly to simulate the transport of mercury in separate applications, whereas the hydrology output from GBMM is used implicitly in the simulation of mercury fate and transport in GBMM. The modeling efforts were a collaboration between the U.S. Geological Survey and the U.S. Environmental Protection Agency, National Exposure Research Laboratory. Calibrations of TOPMODEL and GBMM were done independently while using the same meteorological data and the same period of record of observed data. Two U.S. Geological Survey streamflow-gaging stations were available for comparison of observed daily mean flow with simulated daily mean flow-station 02172300, McTier Creek near Monetta, South Carolina, and station 02172305, McTier Creek near New Holland, South Carolina. The period of record at the Monetta gage covers a broad range of hydrologic conditions, including a drought and a significant wet period. Calibrating the models under these extreme conditions along with the normal flow conditions included in the record enhances the robustness of the two models. Several quantitative assessments of the goodness of fit between model simulations and the observed daily mean flows were done. These included the Nash-Sutcliffe coefficient of model-fit efficiency index, Pearson's correlation coefficient, the root mean square error, the bias, and the mean absolute error. In addition, a number of graphical tools were used to assess how well the models captured the characteristics of the observed data at the Monetta and New Holland streamflow-gaging stations. The graphical tools included temporal plots of simulated and observed daily mean flows, flow-duration curves, single-mass curves, and various residual plots. The results indicated that TOPMODEL and GBMM generally produced simulations that reasonably capture the quantity, variability, and timing of the observed streamflow. For the periods modeled, the total volume of simulated daily mean flows as compared to the total volume of the observed daily mean flow from TOPMODEL was within 1 to 5 percent, and the total volume from GBMM was within 1 to 10 percent. A noticeable characteristic of the simulated hydrographs from both models is the complexity of balancing groundwater recession and flow at the streamgage when flows peak and recede rapidly. However, GBMM results indicate that groundwater recession, which affects the receding limb of the hydrograph, was more difficult to estimate with the spatially explicit curve number approach. Although the purpose of this report is not to directly compare both models, given the characteristics of the McTier Creek watershed and the fact that GBMM uses the spatially explicit curve number approach as compared to the variable-source-area concept in TOPMODEL, GBMM was able to capture the flow characteristics reasonably well.

A physically based analytical model of flood frequency curves

NASA Astrophysics Data System (ADS)

Basso, S.; Schirmer, M.; Botter, G.

2016-09-01

Predicting magnitude and frequency of floods is a key issue in hydrology, with implications in many fields ranging from river science and geomorphology to the insurance industry. In this paper, a novel physically based approach is proposed to estimate the recurrence intervals of seasonal flow maxima. The method links the extremal distribution of streamflows to the stochastic dynamics of daily discharge, providing an analytical expression of the seasonal flood frequency curve. The parameters involved in the formulation embody climate and landscape attributes of the contributing catchment and can be estimated from daily rainfall and streamflow data. Only one parameter, which is linked to the antecedent wetness condition in the watershed, needs to be calibrated on the observed maxima. The performance of the method is discussed through a set of applications in four rivers featuring heterogeneous daily flow regimes. The model provides reliable estimates of seasonal maximum flows in different climatic settings and is able to capture diverse shapes of flood frequency curves emerging in erratic and persistent flow regimes. The proposed method exploits experimental information on the full range of discharges experienced by rivers. As a consequence, model performances do not deteriorate when the magnitude of events with return times longer than the available sample size is estimated. The approach provides a framework for the prediction of floods based on short data series of rainfall and daily streamflows that may be especially valuable in data scarce regions of the world.

A double-blind, randomized, placebo-controlled study of cevimeline in Sjögren's syndrome patients with xerostomia and keratoconjunctivitis sicca.

PubMed

Petrone, Dianne; Condemi, John J; Fife, Rose; Gluck, Oscar; Cohen, Stanley; Dalgin, Paul

2002-03-01

To evaluate the safety and efficacy of 2 dosages of cevimeline for the treatment of xerostomia and keratoconjunctivitis sicca in patients with Sjögren's syndrome. A 12-week double-blind, randomized, placebo-controlled study was performed. Patients were randomly assigned to receive either placebo, 15 mg of cevimeline 3 times daily, or 30 mg of cevimeline 3 times daily. Patients were evaluated at baseline and throughout the study for their global assessment of dryness (mouth, eyes, overall) as well as their subjective assessment of the specific symptoms of dry mouth and dry eyes. Total saliva and tear flow also were measured. Patients taking 30 mg of cevimeline 3 times daily had statistically significant improvements in their subjective global assessment of dry eyes (P = 0.0453), dry mouth (P = 0.0004), and increased salivary flow (P = 0.007). Patients receiving the 30-mg dosage also showed greater objective improvement (increased salivary and lacrimal flow rates, as measured by Schirmer's test) than did patients receiving placebo. Frequently reported adverse events included headache, increased sweating, abdominal pain, and nausea. Treatment with cevimeline at a dosage of 30 mg 3 times daily resulted in substantive improvement by increasing the rate of saliva and tear flow in patients with Sjögren's syndrome, as well as improving subjective symptoms of dry mouth, dry eyes, and overall dryness. The 15-mg dosage relieved some symptoms, and both dosages were well tolerated.

Summary of percentages of zero daily mean streamflow for 712 U.S. Geological Survey streamflow-gaging stations in Texas through 2003

USGS Publications Warehouse

Asquith, William H.; Vrabel, Joseph; Roussel, Meghan C.

2007-01-01

Analysts and managers of surface-water resources might have interest in the zero-flow potential for U.S.Geological Survey (USGS) streamflow-gaging stations in Texas. The USGS, in cooperation with the Texas Commission on Environmental Quality, initiated a data and reporting process to generate summaries of percentages of zero daily mean streamflow for 712 USGS streamflow-gaging stations in Texas. A summary of the percentages of zero daily mean streamflow for most active and inactive, continuous-record gaging stations in Texas provides valuable information by conveying the historical perspective for zero-flow potential for the watershed. The summaries of percentages of zero daily mean streamflow for each station are graphically depicted using two thematic perspectives: annual and monthly. The annual perspective consists of graphs of annual percentages of zero streamflow by year with the addition of lines depicting the mean and median annual percentage of zero streamflow. Monotonic trends in the percentages of zero streamflow also are identified using Kendall's T. The monthly perspective consists of graphs of the percentage of zero streamflow by month with lines added to indicate the mean and median monthly percentage of zero streamflow. One or more summaries could be used in a watershed, river basin, or other regional context by analysts and managers of surface-water resources to guide scientific, regulatory, or other inquiries of zero-flow or other low-flow conditions in Texas.

An assessment of the suspended sediment rating curve approach for load estimation on the Rivers Bandon and Owenabue, Ireland

NASA Astrophysics Data System (ADS)

Harrington, Seán T.; Harrington, Joseph R.

2013-03-01

This paper presents an assessment of the suspended sediment rating curve approach for load estimation on the Rivers Bandon and Owenabue in Ireland. The rivers, located in the South of Ireland, are underlain by sandstone, limestones and mudstones, and the catchments are primarily agricultural. A comprehensive database of suspended sediment data is not available for rivers in Ireland. For such situations, it is common to estimate suspended sediment concentrations from the flow rate using the suspended sediment rating curve approach. These rating curves are most commonly constructed by applying linear regression to the logarithms of flow and suspended sediment concentration or by applying a power curve to normal data. Both methods are assessed in this paper for the Rivers Bandon and Owenabue. Turbidity-based suspended sediment loads are presented for each river based on continuous (15 min) flow data and the use of turbidity as a surrogate for suspended sediment concentration is investigated. A database of paired flow rate and suspended sediment concentration values, collected between the years 2004 and 2011, is used to generate rating curves for each river. From these, suspended sediment load estimates using the rating curve approach are estimated and compared to the turbidity based loads for each river. Loads are also estimated using stage and seasonally separated rating curves and daily flow data, for comparison purposes. The most accurate load estimate on the River Bandon is found using a stage separated power curve, while the most accurate load estimate on the River Owenabue is found using a general power curve. Maximum full monthly errors of - 76% to + 63% are found on the River Bandon with errors of - 65% to + 359% found on the River Owenabue. The average monthly error on the River Bandon is - 12% with an average error of + 87% on the River Owenabue. The use of daily flow data in the load estimation process does not result in a significant loss of accuracy on either river. Historic load estimates (with a 95% confidence interval) were hindcast from the flow record and average annual loads of 7253 ± 673 tonnes on the River Bandon and 1935 ± 325 tonnes on the River Owenabue were estimated to be passing the gauging stations.

Which catchment characteristics control the temporal dependence structure of daily river flows?

NASA Astrophysics Data System (ADS)

Chiverton, Andrew; Hannaford, Jamie; Holman, Ian; Corstanje, Ron; Prudhomme, Christel; Bloomfield, John; Hess, Tim

2014-05-01

A hydrological classification system would provide information about the dominant processes in the catchment enabling information to be transferred between catchments. Currently there is no widely-agreed upon system for classifying river catchments. This paper developed a novel approach to assess the influence that catchment characteristics have on the precipitation-to-flow relationship, using a catchment classification based on the average temporal dependence structure in daily river flow data over the period 1980 to 2010. Temporal dependence in river flow data is driven by the flow pathways, connectivity and storage within the catchment. Temporal dependence was analysed by creating temporally averaged semi-variograms for a set of 116 near-natural catchments (in order to prevent direct anthropogenic disturbances influencing the results) distributed throughout the UK. Cluster analysis, using the variogram, classified the catchments into four well defined clusters driven by the interaction of catchment characteristics, predominantly characteristics which influence the precipitation-to-flow relationship. Geology, depth to gleyed layer in soils, slope of the catchment and the percentage of arable land were significantly different between the clusters. These characteristics drive the temporal dependence structure by influencing the rate at which water moves through the catchment and / or the storage in the catchment. Arable land is correlated with several other variables, hence is a proxy indicating the residence time of the water in the catchment. Finally, quadratic discriminant analysis was used to show that a model with five catchment characteristics is able to predict the temporal dependence structure for un-gauged catchments. This work demonstrates that a variogram-based approach is a powerful and flexible methodology for grouping catchments based on the precipitation-to-flow relationship which could be applied to any set of catchments with a relatively complete daily river flow record.

A statistical analysis of the daily streamflow hydrograph

NASA Astrophysics Data System (ADS)

Kavvas, M. L.; Delleur, J. W.

1984-03-01

In this study a periodic statistical analysis of daily streamflow data in Indiana, U.S.A., was performed to gain some new insight into the stochastic structure which describes the daily streamflow process. This analysis was performed by the periodic mean and covariance functions of the daily streamflows, by the time and peak discharge -dependent recession limb of the daily streamflow hydrograph, by the time and discharge exceedance level (DEL) -dependent probability distribution of the hydrograph peak interarrival time, and by the time-dependent probability distribution of the time to peak discharge. Some new statistical estimators were developed and used in this study. In general features, this study has shown that: (a) the persistence properties of daily flows depend on the storage state of the basin at the specified time origin of the flow process; (b) the daily streamflow process is time irreversible; (c) the probability distribution of the daily hydrograph peak interarrival time depends both on the occurrence time of the peak from which the inter-arrival time originates and on the discharge exceedance level; and (d) if the daily streamflow process is modeled as the release from a linear watershed storage, this release should depend on the state of the storage and on the time of the release as the persistence properties and the recession limb decay rates were observed to change with the state of the watershed storage and time. Therefore, a time-varying reservoir system needs to be considered if the daily streamflow process is to be modeled as the release from a linear watershed storage.

The effectiveness of reducing the daily dose of finasteride in men with benign prostatic hyperplasia

PubMed Central

Sullivan, Michael J; Geller, Jack

2002-01-01

Background Finasteride, a 5 alpha reductase inhibitor, is an established treatment for benign prostatic hyperplasia. The recommended dosage is 5 mg a day, however case reports have show effectiveness with lower doses. The objective of the current study was to determine in men with benign prostatic hyperplasia, previously treated for at least one year with finasteride 5 mg daily, if they will maintain subjective and objective improvements in urinary obstruction when treated with 2.5 mg of finasteride daily for one year. Methods In an open label, prospective study, 40 men with benign prostatic hyperplasia, previously treated for at least one year with 5 mg of finasteride, took 2.5 mg of finasteride daily for one year. Measurements included AUA symptom score, maximum flow rate, voided volume and PSA. Results There were no significant changes in maximum flow rate, voided volume, or AUA symptom score after one year of finasteride 2.5 mg daily therapy. PSA increased significantly, p < .01, after one year of finasteride 2.5 mg daily, 2.0 +1.4 ng/ml, when compared to finasteride 5 mg daily, 1.4+ 1.0 ng/ml. Conclusions The daily dose of finasteride can be reduced to 2.5 mg daily without significant effect on subjective and objective measures of urinary obstruction. Although statistically significant increases in PSA are noted when reducing the daily finasteride dose from 5 mg to 2.5 mg, the clinical significance of a mean .6 ng/ml increase in PSA is questionable. PMID:11818031

Modeling water quality in an urban river using hydrological factors--data driven approaches.

PubMed

Chang, Fi-John; Tsai, Yu-Hsuan; Chen, Pin-An; Coynel, Alexandra; Vachaud, Georges

2015-03-15

Contrasting seasonal variations occur in river flow and water quality as a result of short duration, severe intensity storms and typhoons in Taiwan. Sudden changes in river flow caused by impending extreme events may impose serious degradation on river water quality and fateful impacts on ecosystems. Water quality is measured in a monthly/quarterly scale, and therefore an estimation of water quality in a daily scale would be of good help for timely river pollution management. This study proposes a systematic analysis scheme (SAS) to assess the spatio-temporal interrelation of water quality in an urban river and construct water quality estimation models using two static and one dynamic artificial neural networks (ANNs) coupled with the Gamma test (GT) based on water quality, hydrological and economic data. The Dahan River basin in Taiwan is the study area. Ammonia nitrogen (NH3-N) is considered as the representative parameter, a correlative indicator in judging the contamination level over the study. Key factors the most closely related to the representative parameter (NH3-N) are extracted by the Gamma test for modeling NH3-N concentration, and as a result, four hydrological factors (discharge, days w/o discharge, water temperature and rainfall) are identified as model inputs. The modeling results demonstrate that the nonlinear autoregressive with exogenous input (NARX) network furnished with recurrent connections can accurately estimate NH3-N concentration with a very high coefficient of efficiency value (0.926) and a low RMSE value (0.386 mg/l). Besides, the NARX network can suitably catch peak values that mainly occur in dry periods (September-April in the study area), which is particularly important to water pollution treatment. The proposed SAS suggests a promising approach to reliably modeling the spatio-temporal NH3-N concentration based solely on hydrological data, without using water quality sampling data. It is worth noticing that such estimation can be made in a much shorter time interval of interest (span from a monthly scale to a daily scale) because hydrological data are long-term collected in a daily scale. The proposed SAS favorably makes NH3-N concentration estimation much easier (with only hydrological field sampling) and more efficient (in shorter time intervals), which can substantially help river managers interpret and estimate water quality responses to natural and/or manmade pollution in a more effective and timely way for river pollution management. Copyright © 2014 Elsevier Ltd. All rights reserved.

Quality assurance of a gimbaled head swing verification using feature point tracking.

PubMed

Miura, Hideharu; Ozawa, Shuichi; Enosaki, Tsubasa; Kawakubo, Atsushi; Hosono, Fumika; Yamada, Kiyoshi; Nagata, Yasushi

2017-01-01

To perform dynamic tumor tracking (DTT) for clinical applications safely and accurately, gimbaled head swing verification is important. We propose a quantitative gimbaled head swing verification method for daily quality assurance (QA), which uses feature point tracking and a web camera. The web camera was placed on a couch at the same position for every gimbaled head swing verification, and could move based on a determined input function (sinusoidal patterns; amplitude: ± 20 mm; cycle: 3 s) in the pan and tilt directions at isocenter plane. Two continuous images were then analyzed for each feature point using the pyramidal Lucas-Kanade (LK) method, which is an optical flow estimation algorithm. We used a tapped hole as a feature point of the gimbaled head. The period and amplitude were analyzed to acquire a quantitative gimbaled head swing value for daily QA. The mean ± SD of the period were 3.00 ± 0.03 (range: 3.00-3.07) s and 3.00 ± 0.02 (range: 3.00-3.07) s in the pan and tilt directions, respectively. The mean ± SD of the relative displacement were 19.7 ± 0.08 (range: 19.6-19.8) mm and 18.9 ± 0.2 (range: 18.4-19.5) mm in the pan and tilt directions, respectively. The gimbaled head swing was reliable for DTT. We propose a quantitative gimbaled head swing verification method for daily QA using the feature point tracking method and a web camera. Our method can quantitatively assess the gimbaled head swing for daily QA from baseline values, measured at the time of acceptance and commissioning. © 2016 The Authors. Journal of Applied Clinical Medical Physics published by Wiley Periodicals, Inc. on behalf of American Association of Physicists in Medicine.

Use of plant woody species electrical potential for irrigation scheduling

PubMed Central

Ríos-Rojas, Liliana; Morales-Moraga, David; Alcalde, José A; Gurovich, Luis A

2015-01-01

The electrical response of plants to environmental stimuli can be measured and quantitatively related to the intensity of several stimulating sources, like temperature, solar radiation, soil water content, evapotranspiration rates, sap flow and dendrometric cycles. These relations can be used to assess the influence of different environmental situations on soil water availability to plants, defined as a steady state condition between leaf transpirative flow and soil water flow to plant roots. A restricted soil water flow due to soil dryness can trigger water stress in plants, if the atmospheric evaporative demand is high, causing partial stomata closure as a physiological response to avoid plant dehydration; water stressed and unstressed plants manifest a differential electrical response. Real time plant electrical response measurements can anticipate actions that prevent the plant reaching actual stress conditions, optimizing stomata gas exchange and photosynthetic rates. An electrophysiological sensor developed in this work, allows remote real-time recording information on plant electrical potential (EP) in the field, which is highly related to EP measurements obtained with a laboratory Keithley voltmeter sensor used in an highly controlled experimental setup. Our electrophysiological sensor is a wireless, autonomous devise, which transmits EP information via Internet to a data server. Using both types of sensors (EP electrodes with a Keithley voltmeter and the electrophysiological sensor), we measured in real time the electrical responses of Persea americana and Prunus domestica plants, to induced water deficits. The differential response for 2 scenarios: irrigation and water restriction is identified by a progressive change in slope on the daily maximal and minimal electric signal values in stressed plants, and a zero-slope for similar signals for well-watered plants. Results show a correspondence between measured signals obtained by our electrophysiological sensor and the EP electrodes connected to the Keithley voltmeter in each irrigation stage. Also, both sensors show a daily cyclical signal (circadian cycle). PMID:25826257

Assessing the Impact of Climate Change on Extreme Streamflow and Reservoir Operation for Nuuanu Watershed, Oahu, Hawaii

NASA Astrophysics Data System (ADS)

Leta, O. T.; El-Kadi, A. I.; Dulaiova, H.

2016-12-01

Extreme events, such as flooding and drought, are expected to occur at increased frequencies worldwide due to climate change influencing the water cycle. This is particularly critical for tropical islands where the local freshwater resources are very sensitive to climate. This study examined the impact of climate change on extreme streamflow, reservoir water volume and outflow for the Nuuanu watershed, using the Soil and Water Assessment Tool (SWAT) model. Based on the sensitive parameters screened by the Latin Hypercube-One-factor-At-a-Time (LH-OAT) method, SWAT was calibrated and validated to daily streamflow using the SWAT Calibration and Uncertainty Program (SWAT-CUP) at three streamflow gauging stations. Results showed that SWAT adequately reproduced the observed daily streamflow hydrographs at all stations. This was verified with Nash-Sutcliffe Efficiency that resulted in acceptable values of 0.58 to 0.88, whereby more than 90% of observations were bracketed within 95% model prediction uncertainty interval for both calibration and validation periods, signifying the potential applicability of SWAT for future prediction. The climate change impact on extreme flows, reservoir water volume and outflow was assessed under the Representative Concentration Pathways of 4.5 and 8.5 scenarios. We found wide changes in extreme peak and low flows ranging from -44% to 20% and -50% to -2%, respectively, compared to baseline. Consequently, the amount of water stored in Nuuanu reservoir will be decreased up to 27% while the corresponding outflow rates are expected to decrease up to 37% relative to the baseline. In addition, the stored water and extreme flows are highly sensitive to rainfall change when compared to temperature and solar radiation changes. It is concluded that the decrease in extreme low and peak flows can have serious consequences, such as flooding, drought, with detrimental effects on riparian ecological functioning. This study's results are expected to aid in reservoir operation as well as in identifying appropriate climate change adaptation strategies.

Use of plant woody species electrical potential for irrigation scheduling.

PubMed

Ríos-Rojas, Liliana; Morales-Moraga, David; Alcalde, José A; Gurovich, Luis A

2015-01-01

The electrical response of plants to environmental stimuli can be measured and quantitatively related to the intensity of several stimulating sources, like temperature, solar radiation, soil water content, evapotranspiration rates, sap flow and dendrometric cycles. These relations can be used to assess the influence of different environmental situations on soil water availability to plants, defined as a steady state condition between leaf transpirative flow and soil water flow to plant roots. A restricted soil water flow due to soil dryness can trigger water stress in plants, if the atmospheric evaporative demand is high, causing partial stomata closure as a physiological response to avoid plant dehydration; water stressed and unstressed plants manifest a differential electrical response. Real time plant electrical response measurements can anticipate actions that prevent the plant reaching actual stress conditions, optimizing stomata gas exchange and photosynthetic rates. An electrophysiological sensor developed in this work, allows remote real-time recording information on plant electrical potential (EP) in the field, which is highly related to EP measurements obtained with a laboratory Keithley voltmeter sensor used in an highly controlled experimental setup. Our electrophysiological sensor is a wireless, autonomous devise, which transmits EP information via Internet to a data server. Using both types of sensors (EP electrodes with a Keithley voltmeter and the electrophysiological sensor), we measured in real time the electrical responses of Persea americana and Prunus domestica plants, to induced water deficits. The differential response for 2 scenarios: irrigation and water restriction is identified by a progressive change in slope on the daily maximal and minimal electric signal values in stressed plants, and a zero-slope for similar signals for well-watered plants. Results show a correspondence between measured signals obtained by our electrophysiological sensor and the EP electrodes connected to the Keithley voltmeter in each irrigation stage. Also, both sensors show a daily cyclical signal (circadian cycle).

Effect of exogenous estradiol Benzoate on uterine blood flow in postpartum dairy cows.

PubMed

Rawy, Mohamed; Mido, Shogo; El-Sheikh Ali, Hossam; Derar, Derar; Megahed, Gaber; Kitahara, Go; Osawa, Takeshi

2018-05-01

The objective of this study was to assess the uterine blood flow following estradiol benzoate administration in Holstein-Friesian dairy cows by trans-rectal color Doppler ultrasonography. Six healthy lactating Holstein-Friesian cows were examined daily for 10 days starting at 4 weeks postpartum. All the cows, which were clinically healthy based on vaginal mucus scoring and endometrial cytology, were examined by trans-rectal Doppler ultrasonography to measure pulsatility index (PI), resistance index (RI), time average maximum velocity (TAMAX), blood flow volume (BFV) and diameter in the uterine arteries ipsilateral and contralateral to the previously pregnant uterine horn. On the third day of the experiment, the six cows were administered 10 mg intramuscular injection of estradiol-17β (E 2 ).Blood samples were collected at the time of daily examination for the assessment ofE 2 concentrations.The PI and RI values decreased while TAMAX, BFV and diameter of uterine arteries increased in response toE 2 administration (P < 0.05).There was a high correlation between both the ipsilateral and contralateral uterine arteries for all variables that were studied(r = 0.860, P < 0.0001, r = 0.922, P < 0.0001, r = 0.651, P < 0.0001, r = 0.879, P < 0.0001, r = 0.861, P < 0.0001 for the PI, RI, TAMAX, BFV and uterine arteries diameter, respectively).In conclusion, the greater blood concentrations ofE 2 may be responsible for the greater TAMAX, BFV, increased diameters and decreased PI and RI of the uterine arteries during the puerperium in dairy cows. Copyright © 2018 Elsevier B.V. All rights reserved.

Prediction of Daily Flow Duration Curves and Streamflow for Ungauged Catchments Using Regional Flow Duration Curves

EPA Science Inventory

This study presents a method to predict flow duration curves (FDCs) and streamflow for ungauged catchments in the Mid-Atlantic Region, USA. We selected 29 catchments from the Appalachian Plateau, Ridge and Valley, and Piedmont physiographic provinces to develop and test the propo...

Extreme summer temperatures in Iberia: health impacts and associated synoptic conditions

NASA Astrophysics Data System (ADS)

García-Herrera, R.; Díaz, J.; Trigo, R. M.; Hernández, E.

2005-02-01

This paper examines the effect of extreme summer temperatures on daily mortality in two large cities of Iberia: Lisbon (Portugal) and Madrid (Spain). Daily mortality and meteorological variables are analysed using the same methodology based on Box-Jenkins models. Results reveal that in both cases there is a triggering effect on mortality when maximum daily temperature exceeds a given threshold (34°C in Lisbon and 36°C in Madrid). The impact of most intense heat events is very similar for both cities, with significant mortality values occurring up to 3 days after the temperature threshold has been surpassed. This impact is measured as the percentual increase of mortality associated to a 1°C increase above the threshold temperature. In this respect, Lisbon shows a higher impact, 31%, as compared with Madrid at 21%. The difference can be attributed to demographic and socio-economic factors. Furthermore, the longer life span of Iberian women is critical to explain why, in both cities, females are more susceptible than males to heat effects, with an almost double mortality impact value. The analysis of Sea Level Pressure (SLP), 500hPa geopotential height and temperature fields reveals that, despite being relatively close to each other, Lisbon and Madrid have relatively different synoptic circulation anomalies associated with their respective extreme summer temperature days. The SLP field reveals higher anomalies for Lisbon, but extending over a smaller area. Extreme values in Madrid seem to require a more western location of the Azores High, embracing a greater area over Europe, even if it is not as deep as for Lisbon. The origin of the hot and dry air masses that usually lead to extreme heat days in both cities is located in Northern Africa. However, while Madrid maxima require wind blowing directly from the south, transporting heat from Southern Spain and Northern Africa, Lisbon maxima occur under more easterly conditions, when Northern African air flows over the central Iberian plateau, which had been previously heated.

Sensitivity of peak flow to the change of rainfall temporal pattern due to warmer climate

NASA Astrophysics Data System (ADS)

Fadhel, Sherien; Rico-Ramirez, Miguel Angel; Han, Dawei

2018-05-01

The widely used design storms in urban drainage networks has different drawbacks. One of them is that the shape of the rainfall temporal pattern is fixed regardless of climate change. However, previous studies have shown that the temporal pattern may scale with temperature due to climate change, which consequently affects peak flow. Thus, in addition to the scaling of the rainfall volume, the scaling relationship for the rainfall temporal pattern with temperature needs to be investigated by deriving the scaling values for each fraction within storm events, which is lacking in many parts of the world including the UK. Therefore, this study analysed rainfall data from 28 gauges close to the study area with a 15-min resolution as well as the daily temperature data. It was found that, at warmer temperatures, the rainfall temporal pattern becomes less uniform, with more intensive peak rainfall during higher intensive times and weaker rainfall during less intensive times. This is the case for storms with and without seasonal separations. In addition, the scaling values for both the rainfall volume and the rainfall fractions (i.e. each segment of rainfall temporal pattern) for the summer season were found to be higher than the corresponding results for the winter season. Applying the derived scaling values for the temporal pattern of the summer season in a hydrodynamic sewer network model produced high percentage change of peak flow between the current and future climate. This study on the scaling of rainfall fractions is the first in the UK, and its findings are of importance to modellers and designers of sewer systems because it can provide more robust scenarios for flooding mitigation in urban areas.

USGS Streamgages Linked to the Medium Resolution NHD

USGS Publications Warehouse

Stewart, David W.; Rea, Alan; Wolock, David M.

2006-01-01

The locations of approximately 23,000 current and historical U.S. Geological Survey (USGS) streamgages in the United States and Puerto Rico (with the exception of Alaska) have been snapped to the medium resolution National Hydrography Dataset (NHD). The NHD contains geospatial information about mapped surface-water features, such as streams, lakes, and reservoirs, etc., creating a hydrologic network that can be used to determine what is upstream or downstream from a point of interest on the NHD network. An automated snapping process made the initial determination of the NHD location of each streamgage. These initial NHD locations were comprehensively reviewed by local USGS personnel to ensure that streamgages were snapped to the correct NHD reaches. About 75 percent of the streamgages snapped to the appropriate NHD reach location initially and 25 percent required adjustment and relocation. This process resulted in approximately 23,000 gages being successfully snapped to the NHD. This dataset contains the latitude and longitude coordinates of the point on the NHD to which the streamgage is snapped and the location of the gage house for each streamgage. A process known as indexing may be used to create reference points (event tables) to the NHD reaches, expressed as a reach code and measure (distance along the reach). Indexing is dependent on the version of NHD to which the indexing is referenced. These data are well suited for use in indexing because nearly all the streamgage NHD locations have been reviewed and adjusted if necessary, to ensure they will index to the appropriate NHD reach. Flow characteristics were computed from the daily streamflow data recorded at each streamgage for the period of record. The flow characteristics associated with each streamgage include: *First date (year, month, day) of streamflow data *Last date (year, month, day) of streamflow data *Number of days of streamflow data *Number of days of non-zero streamflow data *Minimum and maximum daily flow for the period of record (cubic feet per second) *Percentiles (1, 5, 10, 20, 25, 50, 75, 80, 90, 95, 99) of daily flow for the period of record (cubic feet per second) *Average and standard deviation of daily flow for the period of record (cubic feet per second) *Mean annual base-flow index (BFI) computed for the period of record (fraction, ranging from 0 to 1) *Year-to-year standard deviation of the annual base-flow index computed for the period of record (fraction) *Number of years of data used to compute the base-flow index (years) The streamflow data used to compute flow characteristics were copied from the NWIS-Web historical daily discharge archive (nadww01.er.usgs.gov:/www/htdocs/nwisweb/data/discharge) on June 15, 2005.

Evaluating potential impacts of species conversion on transpiration in the Piedmont of North Carolina

NASA Astrophysics Data System (ADS)

Boggs, J.; Treasure, E.; Simpson, G.; Domec, J.; Sun, G.; McNulty, S.

2010-12-01

Land management practices that include species conversion or vegetation manipulation can have consequences to surface water availability, groundwater recharge, streamflow generation, and water quality through altering the transpiration processes in forested watersheds. Our objective in this study is to compare stand water use or transpiration in a piedmont mixed hardwood stand (i.e., present stand) to five hypothetical single species stands (i.e., management scenarios), [Quercus spp. (oak), Acer Rubrum (red maple), Liquidambar styraciflua (sweetgum), Liriodendron tulipifera (tulip poplar), and Pinus Taeda (loblolly pine]. Since October 2007, six watersheds with a flume or v-notch weir installed at the watershed outlet have been monitored for baseline streamflow rates (mm d-1). In the summer of 2010, five trees from each of the above species were instrumented with sap flow sensors in the riparian upland of one watershed to develop linkages between stand stream runoff and transpiration. The sap flow or thermal heat dissipation method was used to calculate tree sap flux density for the mixed hardwood stand. Tree sapwood area and stand tree density were then used to compute stand transpiration rates, mm d-1, from June - August 2010. The parameters of the hypothetical single species stands were based on values determined from mixed hardwood stand conditions (e.g., the same stand sapwood area and stand tree density were applied to each option). The diameter at beast height of the monitored trees ranged from 10 cm to 38 cm with a water use range of 1.8 kg d-1 to 104 kg d-1. From our preliminary data, we found daily transpiration from the mixed hardwood stand (2.8 mm d-1 ± 0.06) was significantly (p < 0.05) lower than daily transpiration from the red maple (3.7 mm d-1 ± 0.14) and tulip poplar (3.5 mm d-1 ± 0.12) single species stand management option and significantly (p < 0.05) higher than the loblolly pine (2.3 mm d-1 ± 0.08), sweetgum (2.1 mm d-1 ± 0.08) and oak spp. (1.4 mm d-1 ± 0.04) option. Given that our data represent growing season conditions, these daily transpiration differences are likely a result of physical and physiological differences related to species canopy properties or root distribution and functions. Daily streamflow rates could be reduced by as much as 40% in the red maple scenario because of the increase in daily transpiration. This reduction in flow could have long-term implications and risk to water quality conditions and aquatic species habitat. We will continue to monitor transpiration rates in this mixed hardwood stand to quantify the seasonal variability in water use.

Documentation of a deep percolation model for estimating ground-water recharge

USGS Publications Warehouse

Bauer, H.H.; Vaccaro, J.J.

1987-01-01

A deep percolation model, which operates on a daily basis, was developed to estimate long-term average groundwater recharge from precipitation. It has been designed primarily to simulate recharge in large areas with variable weather, soils, and land uses, but it can also be used at any scale. The physical and mathematical concepts of the deep percolation model, its subroutines and data requirements, and input data sequence and formats are documented. The physical processes simulated are soil moisture accumulation, evaporation from bare soil, plant transpiration, surface water runoff, snow accumulation and melt, and accumulation and evaporation of intercepted precipitation. The minimum data sets for the operation of the model are daily values of precipitation and maximum and minimum air temperature, soil thickness and available water capacity, soil texture, and land use. Long-term average annual precipitation, actual daily stream discharge, monthly estimates of base flow, Soil Conservation Service surface runoff curve numbers, land surface altitude-slope-aspect, and temperature lapse rates are optional. The program is written in the FORTRAN 77 language with no enhancements and should run on most computer systems without modifications. Documentation has been prepared so that program modifications may be made for inclusions of additional physical processes or deletion of ones not considered important. (Author 's abstract)

18 CFR 156.5 - Exhibits.

Code of Federal Regulations, 2011 CFR

2011-04-01

... showing daily design capacity and reflecting operation with proposed transmission facilities. A flow diagram showing daily design capacity of all transmission facilities proposed to be installed and operated... engineering design data in explanation and support of the diagrams and the proposed project, setting forth: (i...

18 CFR 156.5 - Exhibits.

Code of Federal Regulations, 2012 CFR

2012-04-01

... showing daily design capacity and reflecting operation with proposed transmission facilities. A flow diagram showing daily design capacity of all transmission facilities proposed to be installed and operated... engineering design data in explanation and support of the diagrams and the proposed project, setting forth: (i...

18 CFR 156.5 - Exhibits.

Code of Federal Regulations, 2010 CFR

2010-04-01

... showing daily design capacity and reflecting operation with proposed transmission facilities. A flow diagram showing daily design capacity of all transmission facilities proposed to be installed and operated... engineering design data in explanation and support of the diagrams and the proposed project, setting forth: (i...

18 CFR 156.5 - Exhibits.

Code of Federal Regulations, 2014 CFR

2014-04-01

... showing daily design capacity and reflecting operation with proposed transmission facilities. A flow diagram showing daily design capacity of all transmission facilities proposed to be installed and operated... engineering design data in explanation and support of the diagrams and the proposed project, setting forth: (i...

18 CFR 156.5 - Exhibits.

Code of Federal Regulations, 2013 CFR

2013-04-01

... showing daily design capacity and reflecting operation with proposed transmission facilities. A flow diagram showing daily design capacity of all transmission facilities proposed to be installed and operated... engineering design data in explanation and support of the diagrams and the proposed project, setting forth: (i...

Estimating missing daily temperature extremes in Jaffna, Sri Lanka

NASA Astrophysics Data System (ADS)

Thevakaran, A.; Sonnadara, D. U. J.

2018-04-01

The accuracy of reconstructing missing daily temperature extremes in the Jaffna climatological station, situated in the northern part of the dry zone of Sri Lanka, is presented. The adopted method utilizes standard departures of daily maximum and minimum temperature values at four neighbouring stations, Mannar, Anuradhapura, Puttalam and Trincomalee to estimate the standard departures of daily maximum and minimum temperatures at the target station, Jaffna. The daily maximum and minimum temperatures from 1966 to 1980 (15 years) were used to test the validity of the method. The accuracy of the estimation is higher for daily maximum temperature compared to daily minimum temperature. About 95% of the estimated daily maximum temperatures are within ±1.5 °C of the observed values. For daily minimum temperature, the percentage is about 92. By calculating the standard deviation of the difference in estimated and observed values, we have shown that the error in estimating the daily maximum and minimum temperatures is ±0.7 and ±0.9 °C, respectively. To obtain the best accuracy when estimating the missing daily temperature extremes, it is important to include Mannar which is the nearest station to the target station, Jaffna. We conclude from the analysis that the method can be applied successfully to reconstruct the missing daily temperature extremes in Jaffna where no data is available due to frequent disruptions caused by civil unrests and hostilities in the region during the period, 1984 to 2000.

Informed Decision Making Process for Managing Environmental Flows in Small River Basins

NASA Astrophysics Data System (ADS)

Padikkal, S.; Rema, K. P.

2013-03-01

Numerous examples exist worldwide of partial or complete alteration to the natural flow regime of river systems as a consequence of large scale water abstraction from upstream reaches. The effects may not be conspicuous in the case of very large rivers, but the ecosystems of smaller rivers or streams may be completely destroyed over a period of time. While restoration of the natural flow regime may not be possible, at present there is increased effort to implement restoration by regulating environmental flow. This study investigates the development of an environmental flow management model at an icon site in the small river basin of Bharathapuzha, west India. To determine optimal environmental flow regimes, a historic flow model based on data assimilated since 1978 indicated a satisfactory minimum flow depth for river ecosystem sustenance is 0.907 m (28.8 m3/s), a value also obtained from the hydraulic model; however, as three of the reservoirs were already operational at this time a flow depth of 0.922 m is considered a more viable estimate. Analysis of daily stream flow in 1997-2006, indicated adequate flow regimes during the monsoons in June-November, but that sections of the river dried out in December-May with alarming water quality conditions near the river mouth. Furthermore, the preferred minimum `dream' flow regime expressed by stakeholders of the region is a water depth of 1.548 m, which exceeds 50 % of the flood discharge in July. Water could potentially be conserved for environmental flow purposes by (1) the de-siltation of existing reservoirs or (2) reducing water spillage in the transfer between river basins. Ultimately environmental flow management of the region requires the establishment of a co-ordinated management body and the regular assimilation of water flow information from which science based decisions are made, to ensure both economic and environmental concerns are adequately addressed.

Testing the Interstellar Wind Helium Flow Direction with Galileo Euvs Data

NASA Astrophysics Data System (ADS)

Pryor, W. R.; Simmons, K. E.; Ajello, J. M.; Tobiska, W. K.; Retherford, K. D.; Stern, S. A.; Feldman, P. D.; Frisch, P. C.; Bzowski, M.; Grava, C.

2014-12-01

Forty years of measurements of the flow of interstellar helium through the heliosphere suggest that variations of the flow direction with time are possible. We will model Galileo Extreme Ultraviolet Spectrometer (EUVS) data to determine the best-fitting flow direction and compare it to values obtained by other spacecraft. The Galileo EUVS (Hord et al., 1992) was mounted on the spinning part of the spacecraft and obtained interstellar wind hydrogen Lyman-alpha 121.6 nm and helium 58.4 nm data on great circles passing near the ecliptic poles during the interplanetary cruise phase of the mission and also during the Jupiter orbital phase of the mission. The Galileo hydrogen cruise data have been previously published (Hord et al., 1991, Pryor et al., 1992; 1996; 2001), but the helium data have not. Our model was previously used by Ajello et al., 1978, 1979 to model Mariner 10 interstellar wind helium data, and by Stern et al., 2012 and Feldman et al., 2012 to model the interplanetary helium background near the moon in Lunar Reconnaissance Orbiter (LRO) Lyman-alpha Mapping Project (LAMP) data. The model has been updated to include recent determinations of daily helium 58.4 nm solar flux variations and helium losses due to EUV photoionization and electron impact ionization.

Which metric of ambient ozone to predict daily mortality?

NASA Astrophysics Data System (ADS)

Moshammer, Hanns; Hutter, Hans-Peter; Kundi, Michael

2013-02-01

It is well known that ozone concentration is associated with daily cause specific mortality. But which ozone metric is the best predictor of the daily variability in mortality? We performed a time series analysis on daily deaths (all causes, respiratory and cardiovascular causes as well as death in elderly 65+) in Vienna for the years 1991-2009. We controlled for seasonal and long term trend, day of the week, temperature and humidity using the same basic model for all pollutant metrics. We found model fit was best for same day variability of ozone concentration (calculated as the difference between daily hourly maximum and minimum) and hourly maximum. Of these the variability displayed a more linear dose-response function. Maximum 8 h moving average and daily mean value performed not so well. Nitrogen dioxide (daily mean) in comparison performed better when previous day values were assessed. Same day ozone and previous day nitrogen dioxide effect estimates did not confound each other. Variability in daily ozone levels or peak ozone levels seem to be a better proxy of a complex reactive secondary pollutant mixture than daily average ozone levels in the Middle European setting. If this finding is confirmed this would have implications for the setting of legally binding limit values.

Assessment of future variability in extreme precipitation and the potential effects on the wadi flow regime.

PubMed

Gunawardhana, Luminda Niroshana; Al-Rawas, Ghazi A; Kazama, So; Al-Najar, Khalid A

2015-10-01

The objective of this study is to investigate how the magnitude and occurrence of extreme precipitation events are affected by climate change and to predict the subsequent impacts on the wadi flow regime in the Al-Khod catchment area, Muscat, Oman. The tank model, a lumped-parameter rainfall-runoff model, was used to simulate the wadi flow. Precipitation extremes and their potential future changes were predicted using six-member ensembles of general circulation models (GCMs) from the Coupled Model Intercomparison Project Phase 5 (CMIP5). Yearly maxima of the daily precipitation and wadi flow for varying return periods were compared for observed and projected data by fitting the generalized extreme value (GEV) distribution function. Flow duration curves (FDC) were developed and compared for the observed and projected wadi flows. The results indicate that extreme precipitation events consistently increase by the middle of the twenty-first century for all return periods (49-52%), but changes may become more profound by the end of the twenty-first century (81-101%). Consequently, the relative change in extreme wadi flow is greater than twofolds for all of the return periods in the late twenty-first century compared to the relative changes that occur in the mid-century period. Precipitation analysis further suggests that greater than 50% of the precipitation may be associated with extreme events in the future. The FDC analysis reveals that changes in low-to-moderate flows (Q60-Q90) may not be statistically significant, whereas increases in high flows (Q5) are statistically robust (20 and 25% for the mid- and late-century periods, respectively).

Temporal variation in stable isotopes ( 18O and 2H) and major ion concentrations within the Darling River between Bourke and Wilcannia due to variable flows, saline groundwater influx and evaporation

NASA Astrophysics Data System (ADS)

Meredith, K. T.; Hollins, S. E.; Hughes, C. E.; Cendón, D. I.; Hankin, S.; Stone, D. J. M.

2009-11-01

SummaryThe Darling River faces environmental pressures from both climate change and anthropogenic influences leading to a reduction in fresh water availability for the river system. This study uses temporal hydrochemical and stable isotope data ( 18O and 2H) that has been collected over a five-year period (2002 to 2007), as part of the Global Network for Isotopes in Rivers (GNIR) programme, which is aimed at monitoring hydrological processes in large river systems throughout the world. Daily stream flow, monthly stable isotope and major ion chemistry data is presented for sampling locations along the Darling River at Bourke, Louth and Wilcannia, as well as additional more detailed data from locations near Glen Villa. The hydrochemical data is used to partition groundwater influx that is not readily separable by using only the available isotopic data. Individual flow events in the river were found to be isotopically distinct but the Local Evaporation Lines (LELs) that develop after these events have a similar slope indicating similar climatic conditions across this region. After a storm event, fresh waters that are isotopically depleted are introduced to the system and d-excess ( d) values return towards meteoric values. During low flow, the Cl -, Na +, Mg 2+, SO 42-, δ 18O and δ 2H values all increase systematically, and d values become more negative. Hydrochemical and isotopic tracers in conjunction with high resolution sampling strategies have been used to quantify the contribution of evaporation, bank storage release and saline groundwater influx to the evolution of the river waters. Fractional contributions (% of volume) of groundwater to the river water were calculated for different reaches using Cl - concentrations, δ 18O and d values and it was found that river waters comprised of approximately 60-99% saline groundwater during zero flow. The reduced water levels in the river during the drought conditions experienced in the period of this study had detrimental impacts on the surface water system by providing a pathway for saline groundwaters to discharge into the river system. Persistent drought and continued over-abstraction of surface waters will lead to further saline groundwater intrusion along this reach of the river. This work shows that a suite of hydrochemical and isotopic tracers are needed on spatially and temporally significant scales to unravel the hydrological complexities of dryland river systems such as the Darling River.

Patterns of diel variation in nitrate concentrations in the Potomac River

USGS Publications Warehouse

Burns, Douglas A.; Miller, Matthew P.; Pellerin, Brian; Capel, Paul D.

2016-01-01

The Potomac River is a large source of N to Chesapeake Bay, where reducing nutrient loads is a focus of efforts to improve trophic status. Better understanding of NO3– loss, reflected in part by diel variation in NO3– concentrations, may refine model predictions of N loads to the Bay. We analyzed 2 y of high-frequency NO3– sensor data in the Potomac to quantify seasonal variation in the magnitude and timing of diel NO3– loss. Diel patterns were evident, especially during low flow, despite broad seasonal and flow-driven variation in NO3– concentrations. Diel variation was ~0.01 mg N/L in winter and 0.02 to 0.03 mg N/L in summer with intermediate values in spring and autumn, equivalent to <1% of the daily mean NO3– concentration in winter and ~2 to 4% in summer. Maximum diel NO3– values generally occurred in mid- to late morning, with more repeatable patterns in summer and wider variation in autumn and winter. Diel NO3– loss reduced loads by 0.7% in winter and 3% in summer. These losses were less than estimates of total in-stream NO3– load loss across the basin that averaged 33% of the annual groundwater contribution to the river. Water temperature and discharge had stronger relationships to the daily magnitude of diel NO3– variation than did photosynthetically active radiation. Estimated diel areal NO3– loss rates were generally >1000 mg N m–2 d–1, greater than most published values because measurements in this large river integrate over a greater depth/unit stream bottom area than do those from smaller rivers. These diel NO3– patterns are consistent with the influence of photoautotrophic uptake and related denitrification, but we cannot attribute these patterns to assimilation alone because the magnitude and timing of diel dynamics were affected to an unknown extent by processes, such as evapotranspiration, transient storage, and hydrodynamic dispersion. Improvements to diel loss estimates will require additional high-frequency measures, such as dissolved O2, dissolved organic N, and NH4+, and deployment of 2 measurement stations.

Global SWOT Data Assimilation of River Hydrodynamic Model; the Twin Simulation Test of CaMa-Flood

NASA Astrophysics Data System (ADS)

Ikeshima, D.; Yamazaki, D.; Kanae, S.

2016-12-01

CaMa-Flood is a global scale model for simulating hydrodynamics in large scale rivers. It can simulate river hydrodynamics such as river discharge, flooded area, water depth and so on by inputting water runoff derived from land surface model. Recently many improvements at parameters or terrestrial data are under process to enhance the reproducibility of true natural phenomena. However, there are still some errors between nature and simulated result due to uncertainties in each model. SWOT (Surface water and Ocean Topography) is a satellite, which is going to be launched in 2021, can measure open water surface elevation. SWOT observed data can be used to calibrate hydrodynamics model at river flow forecasting and is expected to improve model's accuracy. Combining observation data into model to calibrate is called data assimilation. In this research, we developed data-assimilated river flow simulation system in global scale, using CaMa-Flood as river hydrodynamics model and simulated SWOT as observation data. Generally at data assimilation, calibrating "model value" with "observation value" makes "assimilated value". However, the observed data of SWOT satellite will not be available until its launch in 2021. Instead, we simulated the SWOT observed data using CaMa-Flood. Putting "pure input" into CaMa-Flood produce "true water storage". Extracting actual daily swath of SWOT from "true water storage" made simulated observation. For "model value", we made "disturbed water storage" by putting "noise disturbed input" to CaMa-Flood. Since both "model value" and "observation value" are made by same model, we named this twin simulation. At twin simulation, simulated observation of "true water storage" is combined with "disturbed water storage" to make "assimilated value". As the data assimilation method, we used ensemble Kalman filter. If "assimilated value" is closer to "true water storage" than "disturbed water storage", the data assimilation can be marked effective. Also by changing the input disturbance of "disturbed water storage", acceptable rate of uncertainty at the input may be discussed.

Stream channels: The link between forests and fishes

Treesearch

Kathleen Sullivan; Thomas E. Lisle; C. Andrew Dolloff; Gordon E. Grant; Leslie M. Reid

1987-01-01

Abstract - The hydraulic characteristics of flow through channels are an important component of fish habitat. Salmonids have evolved in stream systems in which water velocity and flow depth vary spatially within the watershed and temporally on a daily, seasonal, and annual basis. Flow requirements vary during different phases of the freshwater life cycle of salmonids...

Curios relationship revealed by looking at long term data sets-The geometry and allometric scaling of diel xylem sap flux in tropical trees.

PubMed

Kunert, Norbert

2016-10-20

Daily xylem sap flux values (daily J s ) and maximum xylem sap flux values (max J s ) from 125 tropical trees from different study sites in the Neotropics were compared. A cross species and study site relationship was found between daily and maximum values. The relationship can be expressed as daily J s =6.5x max J s . The geometrical relationship between the maximum xylem sap flux of a given day is thus defining the daily xylem sap flux rates. Assuming a bell-shaped diurnal sap flux course and a relatively constant day length the maximum xylem sap flux is the only possible changing variable to define daily fluxes. Further, this relationship is showing the inertia of the xylem sap flux as a physical object and highlights the delayed response to environmental changes and its subsequent inevitable susceptibility under environmental stress to hydraulic failure. Copyright © 2016 Elsevier GmbH. All rights reserved.

Effects of including surface depressions in the application of the Precipitation-Runoff Modeling System in the Upper Flint River Basin, Georgia

USGS Publications Warehouse

Viger, Roland J.; Hay, Lauren E.; Jones, John W.; Buell, Gary R.

2010-01-01

This report documents an extension of the Precipitation Runoff Modeling System that accounts for the effect of a large number of water-holding depressions in the land surface on the hydrologic response of a basin. Several techniques for developing the inputs needed by this extension also are presented. These techniques include the delineation of the surface depressions, the generation of volume estimates for the surface depressions, and the derivation of model parameters required to describe these surface depressions. This extension is valuable for applications in basins where surface depressions are too small or numerous to conveniently model as discrete spatial units, but where the aggregated storage capacity of these units is large enough to have a substantial effect on streamflow. In addition, this report documents several new model concepts that were evaluated in conjunction with the depression storage functionality, including: ?hydrologically effective? imperviousness, rates of hydraulic conductivity, and daily streamflow routing. All of these techniques are demonstrated as part of an application in the Upper Flint River Basin, Georgia. Simulated solar radiation, potential evapotranspiration, and water balances match observations well, with small errors for the first two simulated data in June and August because of differences in temperatures from the calibration and evaluation periods for those months. Daily runoff simulations show increasing accuracy with streamflow and a good fit overall. Including surface depression storage in the model has the effect of decreasing daily streamflow for all but the lowest flow values. The report discusses the choices and resultant effects involved in delineating and parameterizing these features. The remaining enhancements to the model and its application provide a more realistic description of basin geography and hydrology that serve to constrain the calibration process to more physically realistic parameter values.

Comprehensive evaluation of Ensemble Multi-Satellite Precipitation Dataset using the Dynamic Bayesian Model Averaging scheme over the Tibetan plateau

NASA Astrophysics Data System (ADS)

Ma, Yingzhao; Yang, Yuan; Han, Zhongying; Tang, Guoqiang; Maguire, Lane; Chu, Zhigang; Hong, Yang

2018-01-01

The objective of this study is to comprehensively evaluate the new Ensemble Multi-Satellite Precipitation Dataset using the Dynamic Bayesian Model Averaging scheme (EMSPD-DBMA) at daily and 0.25° scales from 2001 to 2015 over the Tibetan Plateau (TP). Error analysis against gauge observations revealed that EMSPD-DBMA captured the spatiotemporal pattern of daily precipitation with an acceptable Correlation Coefficient (CC) of 0.53 and a Relative Bias (RB) of -8.28%. Moreover, EMSPD-DBMA outperformed IMERG and GSMaP-MVK in almost all metrics in the summers of 2014 and 2015, with the lowest RB and Root Mean Square Error (RMSE) values of -2.88% and 8.01 mm/d, respectively. It also better reproduced the Probability Density Function (PDF) in terms of daily rainfall amount and estimated moderate and heavy rainfall better than both IMERG and GSMaP-MVK. Further, hydrological evaluation with the Coupled Routing and Excess STorage (CREST) model in the Upper Yangtze River region indicated that the EMSPD-DBMA forced simulation showed satisfying hydrological performance in terms of streamflow prediction, with Nash-Sutcliffe coefficient of Efficiency (NSE) values of 0.82 and 0.58, compared to gauge forced simulation (0.88 and 0.60) at the calibration and validation periods, respectively. EMSPD-DBMA also performed a greater fitness for peak flow simulation than a new Multi-Source Weighted-Ensemble Precipitation Version 2 (MSWEP V2) product, indicating a promising prospect of hydrological utility for the ensemble satellite precipitation data. This study belongs to early comprehensive evaluation of the blended multi-satellite precipitation data across the TP, which would be significant for improving the DBMA algorithm in regions with complex terrain.

PDF added value of a high resolution climate simulation for precipitation

NASA Astrophysics Data System (ADS)

Soares, Pedro M. M.; Cardoso, Rita M.

2015-04-01

General Circulation Models (GCMs) are models suitable to study the global atmospheric system, its evolution and response to changes in external forcing, namely to increasing emissions of CO2. However, the resolution of GCMs, of the order of 1o, is not sufficient to reproduce finer scale features of the atmospheric flow related to complex topography, coastal processes and boundary layer processes, and higher resolution models are needed to describe observed weather and climate. The latter are known as Regional Climate Models (RCMs) and are widely used to downscale GCMs results for many regions of the globe and are able to capture physically consistent regional and local circulations. Most of the RCMs evaluations rely on the comparison of its results with observations, either from weather stations networks or regular gridded datasets, revealing the ability of RCMs to describe local climatic properties, and assuming most of the times its higher performance in comparison with the forcing GCMs. The additional climatic details given by RCMs when compared with the results of the driving models is usually named as added value, and it's evaluation is still scarce and controversial in the literuature. Recently, some studies have proposed different methodologies to different applications and processes to characterize the added value of specific RCMs. A number of examples reveal that some RCMs do add value to GCMs in some properties or regions, and also the opposite, elighnening that RCMs may add value to GCM resuls, but improvements depend basically on the type of application, model setup, atmospheric property and location. The precipitation can be characterized by histograms of daily precipitation, or also known as probability density functions (PDFs). There are different strategies to evaluate the quality of both GCMs and RCMs in describing the precipitation PDFs when compared to observations. Here, we present a new method to measure the PDF added value obtained from dynamical downscaling, based on simple PDF skill scores. The measure can assess the full quality of the PDFs and at the same time integrates a flexible manner to weight differently the PDF tails. In this study we apply the referred method to characaterize the PDF added value of a high resolution simulation with the WRF model. Results from a WRF climate simulation centred at the Iberian Penisnula with two nested grids, a larger one at 27km and a smaller one at 9km. This simulation is forced by ERA-Interim. The observational data used covers from rain gauges precipitation records to observational regular grids of daily precipitation. Two regular gridded precipitation datasets are used. A Portuguese grid precipitation dataset developed at 0.2°× 0.2°, from observed rain gauges daily precipitation. A second one corresponding to the ENSEMBLES observational gridded dataset for Europe, which includes daily precipitation values at 0.25°. The analisys shows an important PDF added value from the higher resolution simulation, regarding the full PDF and the extremes. This method shows higher potential to be applied to other simulation exercises and to evaluate other variables.

Methods for estimating selected flow-duration and flood-frequency characteristics at ungaged sites in Central Idaho

USGS Publications Warehouse

Kjelstrom, L.C.

1998-01-01

Methods for estimating daily mean discharges for selected flow durations and flood discharge for selected recurrence intervals at ungaged sites in central Idaho were applied using data collected at streamflow-gaging stations in the area. The areal and seasonal variability of discharge from ungaged drainage basins may be described by estimating daily mean discharges that are exceeded 20, 50, and 80 percent of the time each month. At 73 gaging stations, mean monthly discharge was regressed with discharge at three points—20, 50, and 80—from daily mean flow-duration curves for each month. Regression results were improved by dividing the study area into six regions. Previously determined estimates of mean monthly discharge from about 1,200 ungaged drainage basins provided the basis for applying the developed techniques to the ungaged basins. Estimates of daily mean discharges that are exceeded 20, 50, and 80 percent of the time each month at ungaged drainage basins can be made by multiplying mean monthly discharges estimated at ungaged sites by a regression factor for the appropriate region. In general, the flow-duration data were less accurately estimated at discharges exceeded 80 percent of the time than at discharges exceeded 20 percent of the time. Curves drawn through the three points for each of the six regions were most similar in July and most different from December through March. Coefficients of determination of the regressions indicate that differences in mean monthly discharge largely explain differences in discharge at points on the daily mean flow-duration curve. Inherent in the method are errors in the technique used to estimate mean monthly discharge. Flood discharge estimates for selected recurrence intervals at ungaged sites upstream or downstream from gaging stations can be determined by a transfer technique. A weighted ratio of drainage area times flood discharge for selected recurrence intervals at the gaging station can be used to estimate flood discharge at the ungaged site. Best results likely are obtained when the difference between gaged and ungaged drainage areas is small.

On the distributions of annual and seasonal daily rainfall extremes in central Arizona and their spatial variability

NASA Astrophysics Data System (ADS)

Mascaro, Giuseppe

2018-04-01

This study uses daily rainfall records of a dense network of 240 gauges in central Arizona to gain insights on (i) the variability of the seasonal distributions of rainfall extremes; (ii) how the seasonal distributions affect the shape of the annual distribution; and (iii) the presence of spatial patterns and orographic control for these distributions. For this aim, recent methodological advancements in peak-over-threshold analysis and application of the Generalized Pareto Distribution (GPD) were used to assess the suitability of the GPD hypothesis and improve the estimation of its parameters, while limiting the effect of short sample sizes. The distribution of daily rainfall extremes was found to be heavy-tailed (i.e., GPD shape parameter ξ > 0) during the summer season, dominated by convective monsoonal thunderstorms. The exponential distribution (a special case of GPD with ξ = 0) was instead showed to be appropriate for modeling wintertime daily rainfall extremes, mainly caused by cold fronts transported by westerly flow. The annual distribution exhibited a mixed behavior, with lighter upper tails than those found in summer. A hybrid model mixing the two seasonal distributions was demonstrated capable of reproducing the annual distribution. Organized spatial patterns, mainly controlled by elevation, were observed for the GPD scale parameter, while ξ did not show any clear control of location or orography. The quantiles returned by the GPD were found to be very similar to those provided by the National Oceanic and Atmospheric Administration (NOAA) Atlas 14, which used the Generalized Extreme Value (GEV) distribution. Results of this work are useful to improve statistical modeling of daily rainfall extremes at high spatial resolution and provide diagnostic tools for assessing the ability of climate models to simulate extreme events.

A coupled metabolic-hydraulic model and calibration scheme for estimating of whole-river metabolism during dynamic flow conditions

USGS Publications Warehouse

Payn, Robert A.; Hall, Robert O Jr.; Kennedy, Theodore A.; Poole, Geoff C; Marshall, Lucy A.

2017-01-01

Conventional methods for estimating whole-stream metabolic rates from measured dissolved oxygen dynamics do not account for the variation in solute transport times created by dynamic flow conditions. Changes in flow at hourly time scales are common downstream of hydroelectric dams (i.e. hydropeaking), and hydrologic limitations of conventional metabolic models have resulted in a poor understanding of the controls on biological production in these highly managed river ecosystems. To overcome these limitations, we coupled a two-station metabolic model of dissolved oxygen dynamics with a hydrologic river routing model. We designed calibration and parameter estimation tools to infer values for hydrologic and metabolic parameters based on time series of water quality data, achieving the ultimate goal of estimating whole-river gross primary production and ecosystem respiration during dynamic flow conditions. Our case study data for model design and calibration were collected in the tailwater of Glen Canyon Dam (Arizona, USA), a large hydropower facility where the mean discharge was 325 m3 s 1 and the average daily coefficient of variation of flow was 0.17 (i.e. the hydropeaking index averaged from 2006 to 2016). We demonstrate the coupled model’s conceptual consistency with conventional models during steady flow conditions, and illustrate the potential bias in metabolism estimates with conventional models during unsteady flow conditions. This effort contributes an approach to solute transport modeling and parameter estimation that allows study of whole-ecosystem metabolic regimes across a more diverse range of hydrologic conditions commonly encountered in streams and rivers.

Cerebral flow velocities during daily activities depend on blood pressure in patients with chronic ischemic infarctions

PubMed Central

Novak, Vera; Hu, Kun; Desrochers, Laura; Novak, Peter; Caplan, Louis; Lipsitz, Lewis; Selim, Magdy

2010-01-01

Background Target blood pressure (BP) values for optimal cerebral perfusion after an ischemic stroke are still debated. We sought to examine the relationship between BP and cerebral blood flow velocities (BFV) during daily activities. Methods We studied 43 patients with chronic large vessel ischemic infarctions in middle cerebral artery (MCA) territory (aged 64.2±8.94 years; at 6.1±4.9 years after stroke), and 67 age-matched controls. BFV in MCAs were measured during supine baseline, sitting, standing and tilt. A regression analysis and a dynamic phase analysis were used to quantify BP-BFV relationship. Results The mean arterial pressure was similar between the groups (89±15 mmHg). Baseline BFV were lower by ~ 30% in the stroke patients compared to the controls (p=0.0001). BFV declined further with postural changes, and remained lower in the stroke group during sitting (p=0.003), standing (p=0.003) and tilt (p=0.002) as compared to the control group. Average BFV on the stroke side were positively correlated with BP during baseline (R=0.54, p=0.0022, the slope 0.46 cm/s/mm Hg) and tilt (R=0.52, p=0.0028, the slope 0.40 cm/s/mm Hg). Regression analysis suggested that BFV may increase ~ 30-50% at mean BP > 100 mmHg. Orthostatic hypotension during the first minute of tilt or standing was independently associated with lower BFV on the stroke side (p=0.0008). Baseline BP-BFV phase shift derived from the phase analysis was smaller on the stroke-side (p=0.0006). Conclusion We found that BFV are lower in stroke patients and daily activities such as standing could induce hypoperfusion. BFV increase with mean arterial pressure > 100 mmHg. Dependency of BFV on arterial pressure may have implications for BP management after stroke. Further prospective investigations are needed to determine the impact of these findings on functional recovery and strategies to improve perfusion pressure during daily activities after ischemic stroke. PMID:19959536

Cerebral flow velocities during daily activities depend on blood pressure in patients with chronic ischemic infarctions.

PubMed

Novak, Vera; Hu, Kun; Desrochers, Laura; Novak, Peter; Caplan, Louis; Lipsitz, Lewis; Selim, Magdy

2010-01-01

Target blood pressure (BP) values for optimal cerebral perfusion after an ischemic stroke are still debated. We sought to examine the relationship between BP and cerebral blood flow velocities (BFVs) during daily activities. We studied 43 patients with chronic large vessel ischemic infarctions in the middle cerebral artery territory (aged 64.2+/-8.94 years; at 6.1+/-4.9 years after stroke) and 67 age-matched control subjects. BFVs in middle cerebral arteries were measured during supine baseline, sitting, standing, and tilt. A regression analysis and a dynamic phase analysis were used to quantify the BP-BFV relationship. The mean arterial pressure was similar between the groups (89+/-15 mm Hg). Baseline BFVs were lower by approximately 30% in the patients with stroke compared with the control subjects (P=0.0001). BFV declined further with postural changes and remained lower in the stroke group during sitting (P=0.003), standing (P=0.003), and tilt (P=0.002) as compared with the control group. Average BFVs on the stroke side were positively correlated with BP during baseline (R=0.54, P=0.0022, the slope 0.46 cm/s/mm Hg) and tilt (R=0.52, P=0.0028, the slope 0.40 cm/s/mm Hg). Regression analysis suggested that BFV may increase approximately 30% to 50% at mean BP >100 mm Hg. Orthostatic hypotension during the first minute of tilt or standing was independently associated with lower BFV on the stroke side (P=0.0008). Baseline BP-BFV phase shift derived from the phase analysis was smaller on the stroke side (P=0.0006). We found that BFVs are lower in patients with stroke and daily activities such as standing could induce hypoperfusion. BFVs increase with mean arterial pressure >100 mm Hg. Dependency of BFV on arterial pressure may have implications for BP management after stroke. Further prospective investigations are needed to determine the impact of these findings on functional recovery and strategies to improve perfusion pressure during daily activities after ischemic stroke.

Geomorphological origin of recession curves

NASA Astrophysics Data System (ADS)

Biswal, Basudev; Marani, Marco

2010-12-01

We identify a previously undetected link between the river network morphology and key recession curves properties through a conceptual-physical model of the drainage process of the riparian unconfined aquifer. We show that the power-law exponent, α, of -dQ/dt vs. Q curves is related to the power-law exponent of N(l) vs. G(l) curves (which we show to be connected to Hack's law), where l is the downstream distance from the channel heads, N(l) is the number of channel reaches exactly located at a distance l from their channel head, and G(l) is the total length of the network located at a distance greater or equal to l from channel heads. Using Digital Terrain Models and daily discharge observations from 67 US basins we find that geomorphologic α estimates match well the values obtained from recession curves analyses. Finally, we argue that the link between recession flows and network morphology points to an important role of low-flow discharges in shaping the channel network.

Oceanic corrosion test of bare and zinc-protected aluminum alloys for seawater heat exchangers

NASA Technical Reports Server (NTRS)

Sasscer, D. S.; Morgan, T. O.; Rivera, C.; Ernst, R.; Scott, A. C.; Summerson, T. J.

1982-01-01

Bare 3004 tubes, 7072 Alclad 3004 tubes, and bare and zinc diffusion treated 3003 extrusions from a brazed aluminum, plate-fin heat exchanger were exposed to 1.8 m/sec flowing seawater aboard an open ocean test facility moored 3.4 km off the southeast coast of Puerto Rico. After six months exposure, the average corrosion rates for most varieties of aluminum materials converged to a low value of 0.015 mm/yr (0.6 mils/yr). Pitting did not occur in bare 3003 and 3004 samples during the six month test. Pitting did occur to varying degrees in the Alclad and zinc diffusion treated material, but did not penetrate to the base metal. Biofouling countermeasures (intermittent chlorination and brushing) did not affect the corrosion rates to any significant extent. Intermittent chlorination at a level of 0.5 ppm for 28 minutes daily controlled microbiofouling of the samples but did not prevent the development of a macrobiofouling community in areas of the plumbing with low flow.

Methods for estimating drought streamflow probabilities for Virginia streams

USGS Publications Warehouse

Austin, Samuel H.

2014-01-01

Maximum likelihood logistic regression model equations used to estimate drought flow probabilities for Virginia streams are presented for 259 hydrologic basins in Virginia. Winter streamflows were used to estimate the likelihood of streamflows during the subsequent drought-prone summer months. The maximum likelihood logistic regression models identify probable streamflows from 5 to 8 months in advance. More than 5 million streamflow daily values collected over the period of record (January 1, 1900 through May 16, 2012) were compiled and analyzed over a minimum 10-year (maximum 112-year) period of record. The analysis yielded the 46,704 equations with statistically significant fit statistics and parameter ranges published in two tables in this report. These model equations produce summer month (July, August, and September) drought flow threshold probabilities as a function of streamflows during the previous winter months (November, December, January, and February). Example calculations are provided, demonstrating how to use the equations to estimate probable streamflows as much as 8 months in advance.

Flow monitoring along the western Tamiami Trail between County Road 92 and State Road 29 in support of the Comprehensive Everglades Restoration Plan, 2007-2010

USGS Publications Warehouse

Booth, Amanda C.; Soderqvist, Lars E.; Berry, Marcia C.

2014-01-01

The construction of U.S. Highway 41 (Tamiami Trail), the Southern Golden Gate Estates development, and the Barron River Canal has altered the flow of freshwater to the Ten Thousand Islands estuary of Southwest Florida. Two restoration projects, the Picayune Strand Restoration Project and the Tamiami Trail Culverts Project, both associated with the Comprehensive Everglades Restoration Plan, were initiated to address this issue. Quantifying the flow of freshwater to the estuary is essential to assessing the effectiveness of these projects. The U.S. Geological Survey conducted a study between March 2006 and September 2010 to quantify the freshwater flowing under theTamiami Trail between County Road 92 and State Road 29 in southwest Florida, excluding the Faka Union Canal (which is monitored by South Florida Water Management District). The study period was after the completion of the Tamiami Trail Culverts Project and prior to most of the construction related to the Picayune Restoration Project. The section of the Tamiami Trail that was studied contains too many structures (35 bridges and 16 culverts) to cost-effectively measure each structure on a continuous basis, so the area was divided into seven subbasins. One bridge within each of the subbasins was instrumented with an acoustic Doppler velocity meter. The index velocity method was used to compute discharge at the seven instrumented bridges. Periodic discharge measurements were made at all structures, using acoustic Doppler current profilers at bridges and acoustic Doppler velocity meters at culverts. Continuous daily mean values of discharge for the uninstrumented structures were calculated on the basis of relations between the measured discharge at the uninstrumented stations and the discharge and stage at the instrumented bridge. Estimates of daily mean discharge are available beginning in 2006 or 2007 through September 2010 for all structures. Subbasin comparison is limited to water years 2008–2010. The Faka Union Canal contributed more than half (on average 60 percent) of the flow under the Tamiami Trail between State Road 29 and County Road 92 during water years 2008–2010. During water years 2008–2010, an average 9 percent of the flow through the study area came from west of the Faka Union Canal and an average 31 percent came from east of the Faka Union Canal. Flow data provided by this study serve as baseline information about the seasonal and spatial distribution of freshwater flow under the Tamiami Trail between County Road 92 and State Road 29, and study results provide data to evaluate restoration efforts.

Graphical method for estimating occurrence and duration of a critical low flow in the Sacramento River at Freeport, California

USGS Publications Warehouse

Harmon, J.G.

1983-01-01

Sacramento County expects to begin operation of the Sacramento Regional Wastewater Treatment Plant in 1982. The California State Water Resources Control Board has ruled that the plant will not be allowed to release effluent into the Sacramento River when flow in the river is 4,000 cubic feet per second or less. Depending on tide condition, flows less than 4,000 cubic feet per second may occur either once or twice during each 24-hour 50-minute tide cycle when the daily mean flow is less than about 12,000 cubic feet per second. Daily means flows less than 12,000 cubic feet per second occur about 28% of the time. Riverflow at the plant outfall is monitored by an acoustic streamflow-measuring system. Regulation of effluent released from the plant will normally be based on real-time flow data computed by the acoustic system. A graphical method for determining the occurrence and duration of flows of 4,000 cubic feet per second and less was developed as a backup system to be used if a temporary failure in the acoustic system occurs. (USGS)

Topography significantly influencing low flows in snow-dominated watersheds

NASA Astrophysics Data System (ADS)

Li, Qiang; Wei, Xiaohua; Yang, Xin; Giles-Hansen, Krysta; Zhang, Mingfang; Liu, Wenfei

2018-03-01

Watershed topography plays an important role in determining the spatial heterogeneity of ecological, geomorphological, and hydrological processes. Few studies have quantified the role of topography in various flow variables. In this study, 28 watersheds with snow-dominated hydrological regimes were selected with daily flow records from 1989 to 1996. These watersheds are located in the Southern Interior of British Columbia, Canada, and range in size from 2.6 to 1780 km2. For each watershed, 22 topographic indices (TIs) were derived, including those commonly used in hydrology and other environmental fields. Flow variables include annual mean flow (Qmean), Q10 %, Q25 %, Q50 %, Q75 %, Q90 %, and annual minimum flow (Qmin), where Qx % is defined as the daily flow that occurred each year at a given percentage (x). Factor analysis (FA) was first adopted to exclude some redundant or repetitive TIs. Then, multiple linear regression models were employed to quantify the relative contributions of TIs to each flow variable in each year. Our results show that topography plays a more important role in low flows (flow magnitudes ≤ Q75 %) than high flows. However, the effects of TIs on different flow magnitudes are not consistent. Our analysis also determined five significant TIs: perimeter, slope length factor, surface area, openness, and terrain characterization index. These can be used to compare watersheds when low flow assessments are conducted, specifically in snow-dominated regions with the watershed size less than several thousand square kilometres.

Water quality in Reedy Fork and Buffalo Creek basins in the Greensboro area, North Carolina, 1986-87

USGS Publications Warehouse

Davenport, M.S.

1989-01-01

Water and bottom-sediment samples were collected from April 1986 through September 1987 at 19 sites in Guilford County and the City of Greensboro, North Carolina. Sampling locations included 13 stream sites, two lakes that supply the City of Greensboro with drinking water, two City of Greensboro finished drinking-water filtration plants, and effluent from the two municipal wastewater plants prior to outfall into receiving streams. Water sampling consisted of six surveys during various stages of steady ground-water flow at all sites and high-flow-event sampling during two storms at six sites. Bottom-sediment samples were collected at three sites during two routine sampling surveys. A summary of nearly 22, 000 separate chemical or physical analyses of water samples or bottom sediment is presented and discussed as individual values, ranges of values, or median values with respect to the locations of sampling sites, streamflow conditions, or other information bearing on water-quality conditions under discussion. The results include discussions of general water-quality indicators; major ion, nutrient, and trace-element concentrations; acid and base/neutral extractable organic compounds; volatile organic compounds; and organochlorine and organophosphorus pesticides detected at each sampling site. Loadings of selected constituents are also estimated on a yearly and daily basis. The quality of the raw and finished water, municipal effluents, and streams in the Greensboro area are characterized by using State and Federal water-quality standards. Inorganic constituents most commonly found in excess of standards were iron, copper, zinc, arsenic, phosphorus, manganese, cyanide, and mercury. Relatively few organic compounds were detected; however, those consistently reported were phthalate, thihalomethane, organophosphorus pesticide, benzol, and phenolic compounds. Selected inorganic, physical, and total organic carbon data are used in a Wilcoxon test for two independent variables to statistically compare water-quality characteristics in selected rural, semideveloped and urban basins. During low-flow sampling, the constituents that differed significantly among all sites were calcium, magnesium, and chloride. During low flows, concentrations of orthophosphate, fluoride, sulfate, and TOC differed at the urban site from the rural and semideveloped and urban sites. There were no significant differences among sites in concentrations of sodium, suspended sediment, nickel, zinc, copper, and mercury during low flows. The Wilcoxon test performed on high-flow data indicated that concentrations of TOC, chloride, sulfate, suspended sediment, and nickel were not significantly different among the sites.

Hydropeaking in Nordic rivers - combined analysis from effects of changing climate conditions and energy demands to river regimes

NASA Astrophysics Data System (ADS)

Ashraf, Faisal Bin; Marttila, Hannu; Torabi Haghighi, Ali; Alfredsen, Knut; Riml, Joakim; Kløve, Bjørn

2017-04-01

Increasing national and international demands for more flexible management of the energy resources with more non-storable renewables being used in adapting to the ongoing climate change will influence hydropower operations. Damming and regulation practices of river systems causes homogenization of long term river dynamics but also higher temporal sub-daily flow variations i.e. hydropeaking. In Nordic countries, many major rivers and lakes are regulated for hydropower purposes, which have caused considerable changes in river biotic, hydrologic and morphologic structures. Due to rapidly changing energy markets in the Nordic countries (deregulation of the power market and adding of renewable but intermittent sources of energy like, wind, solar, etc.) sub-daily flow conditions are under change within regulated river systems due to the increased demand on hydropower for providing balancing power. However, holistic analysis from changes in energy markets and its effect on sub-daily river regimes is lacking. This study analyzes the effects of hydropeaking on river regime in Finland, Sweden and Norway using long term high resolution data (15 minutes to hourly time interval) from 72 pristine and 136 regulated rivers with large spatial coverage across Fennoscandia. Since the sub-daily discharge variation is masked through the monthly or daily analyzes, in order to quantify these changes high resolution data is needed. In our study we will document, characterize and classify the impacts of sub-daily flow variation due to regulation and climatic variation on various river systems in Fennoscandia. Further, with increasing social demands for ecosystem services in regulated rivers, it is important to evaluate the new demand and update hydropower operation plan accordingly. We will analyse ecological response relationships along gradients of hydrological alteration for the biological communities, processes of river ecosystems and climate boundaries together with considering the new energy demands and consumptions in the Nordic energy market. For assessing sub-daily flow data various already available indices will be used which measure the magnitude of hydropeaking and temporal rate of discharge changes. For the impact quantification, the hydropeaking pressure will be calculated and set for each of the impact class. Also work will be done to formulate some new indices which will specifically quantify sub-daily change in the boreal rivers. We select representative case-studies, future scenarios and develop optimization methods to reduce impacts on aquatic ecosystems and maximizing the economic benefits from hydropower generation for stakeholders.

40 CFR 60.213 - Monitoring of operations.

Code of Federal Regulations, 2010 CFR

2010-07-01

..., maintain, and operate a flow monitoring device which can be used to determine the mass flow of phosphorus... daily record of equivalent P2O5 feed by first determining the total mass rate in Mg/hr of phosphorus...

40 CFR 60.213 - Monitoring of operations.

Code of Federal Regulations, 2011 CFR

2011-07-01

..., maintain, and operate a flow monitoring device which can be used to determine the mass flow of phosphorus... daily record of equivalent P2O5 feed by first determining the total mass rate in Mg/hr of phosphorus...

40 CFR 98.323 - Calculating GHG emissions.

Code of Federal Regulations, 2011 CFR

2011-07-01

... the meter automatically corrects for temperature and pressure, replace “520 °R/Ti × Pi/1 atm” with “1... at which flow is measured (°R). Pi = Daily pressure at which flow is measured (atm). 1,440...

Nutrient-based ecological consideration of a temporary river catchment affected by a reservoir operation to facilitate efficient management.

PubMed

Tzoraki, Ourania A; Dörflinger, Gerald; Kathijotes, Nicholas; Kontou, Artemis

2014-01-01

The water quality status of the Kouris river in Cyprus was examined in order to fulfil the requirements for ecological quality as defined by the Water Framework Directive-2000/60/EC. Nitrate concentration (mean value) was increased in the Limnatis (2.8 mg L(-1)) tributary in comparison with the Kryos (2.1 mg L(-1)) and Kouris (1.0 mg L(-1)) tributaries depicting the influence of anthropogenic activities. The total maximum daily nutrients loads (TMDLs) based on the flow duration curves approach, showed that nutrients loads exceeded threshold values (33.3-75.6% in all hydrologic condition classes in the Kouris tributary, and 65-78% in the Limnatis tributary) especially under low flow conditions. The TMDL graph is intended to guide the temporal schedule for chemical sampling in all hydrologic classes. Kouris reservoir is an oligotrophic system, strongly influenced by the river's flash-flood character but also by the implemented management practices. Kouris river outflow, which was reduced to one-tenth in the post dam period altered the wetland hydrologic network and contributed to the decrease of aquifer thickness. Continuous evaluation and update of the River Basin Management Plans will be the basis for the sustainable development of the Kouris basin.

Tree water storage and its diurnal dynamics related to sap flow and changes in stem volume in old-growth Douglas-fir trees.

PubMed

Cermák, Jan; Kucera, Jiri; Bauerle, William L; Phillips, Nathan; Hinckley, Thomas M

2007-02-01

Diurnal and seasonal tree water storage was studied in three large Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco) trees at the Wind River Canopy Crane Research site. Changes in water storage were based on measurements of sap flow and changes in stem volume and tissue water content at different heights in the stem and branches. We measured sap flow by two variants of the heat balance method (with internal heating in stems and external heating in branches), stem volume with electronic dendrometers, and tissue water content gravimetrically. Water storage was calculated from the differences in diurnal courses of sap flow at different heights and their integration. Old-growth Douglas-fir trees contained large amounts of free water: stem sapwood was the most important storage site, followed by stem phloem, branch sapwood, branch phloem and needles. There were significant time shifts (minutes to hours) between sap flow measured at different positions within the transport system (i.e., stem base to shoot tip), suggesting a highly elastic transport system. On selected fine days between late July and early October, when daily transpiration ranged from 150 to 300 liters, the quantity of stored water used daily ranged from 25 to 55 liters, i.e., about 20% of daily total sap flow. The greatest amount of this stored water came from the lower stem; however, proportionally more water was removed from the upper parts of the tree relative to their water storage capacity. In addition to lags in sap flow from one point in the hydrolic pathway to another, the withdrawal and replacement of stored water was reflected in changes in stem volume. When point-to-point lags in sap flow (minutes to hours near the top and stem base, respectively) were considered, there was a strong linear relationship between stem volume changes and transpiration. Volume changes of the whole tree were small (equivalent to 14% of the total daily use of stored water) indicating that most stored water came from the stem and from its inelastic (sapwood) tissues. Whole tree transpiration can be maintained with stored water for about a week, but it can be maintained with stored water from the upper crown alone for no more than a few hours.

Concentration and flux of total and dissolved phosphorus, total nitrogen, chloride, and total suspended solids for monitored tributaries of Lake Champlain, 1990-2012

USGS Publications Warehouse

Medalie, Laura

2014-01-01

Annual and daily concentrations and fluxes of total and dissolved phosphorus, total nitrogen, chloride, and total suspended solids were estimated for 18 monitored tributaries to Lake Champlain by using the Weighted Regressions on Time, Discharge, and Seasons regression model. Estimates were made for 21 or 23 years, depending on data availability, for the purpose of providing timely and accessible summary reports as stipulated in the 2010 update to the Lake Champlain “Opportunities for Action” management plan. Estimates of concentration and flux were provided for each tributary based on (1) observed daily discharges and (2) a flow-normalizing procedure, which removed the random fluctuations of climate-related variability. The flux bias statistic, an indicator of the ability of the Weighted Regressions on Time, Discharge, and Season regression models to provide accurate representations of flux, showed acceptable bias (less than ±10 percent) for 68 out of 72 models for total and dissolved phosphorus, total nitrogen, and chloride. Six out of 18 models for total suspended solids had moderate bias (between 10 and 30 percent), an expected result given the frequently nonlinear relation between total suspended solids and discharge. One model for total suspended solids with a very high bias was influenced by a single extreme value; however, removal of that value, although reducing the bias substantially, had little effect on annual fluxes.

Modeling Integrated Cave Drip Recharge Data using DReAM (Daily Recharge Assessment Model) in a Dry Eastern Mediterranean Area, Sif Cave - Israel

NASA Astrophysics Data System (ADS)

Anker, Y.; Sheffer, N. A.; Scanlon, B. R.; Gimburg, A.; Morin, E.

2010-12-01

Understanding recharge mechanisms and controls in karst regions is extremely important for managing water resources because of the dynamic nature of the system. To better understand this mechanism, a cave in the recharge area of the karstic Western Mountain Aquifer (WMA) of Israel was equipped to measure precipitation infiltration (2006-2008) by collecting integrated water drips from three areas in the cave (14, 46, and 52 m2 areas). Barrels equipped with pressure transducers record drip rate and volume for each of the three areas and enable estimation of recharge. A water budget model - DReAM (Daily Recharge Assessment Model) was used to quantify and predict infiltration behavior at the cave. DReAM includes calculations of all water cycle components - precipitation, evapotranspiration, runoff and recharge. The model was calibrated and validated using two independent sets of values, providing good agreement between calculated and observed data. Modeling results agree with previous studies that show: 1) three distinct flow paths (slow, intermediate, and fast flows) of water infiltrating at the cave; 2) a threshold of ~100 mm rain at the beginning of the rainy season for infiltration to begin; and 3) a decrease in lag time between rain events and infiltration response throughout the rainy season. This modeling tool and analysis approach can translate precipitation to groundwater recharge which will be very important for projecting future water resources in response to climate variability.

Measuring and modeling the variation in species-specific transpiration in temperate deciduous hardwoods.

PubMed

Bowden, Joseph D; Bauerle, William L

2008-11-01

We investigated which parameters required by the MAESTRA model were most important in predicting leaf-area-based transpiration in 5-year-old trees of five deciduous hardwood species-yoshino cherry (Prunus x yedoensis Matsum.), red maple (Acer rubrum L. 'Autumn Flame'), trident maple (Acer buergeranum Miq.), Japanese flowering cherry (Prunus serrulata Lindl. 'Kwanzan') and London plane-tree (Platanus x acerifolia (Ait.) Willd.). Transpiration estimated from sap flow measured by the heat balance method in branches and trunks was compared with estimates predicted by the three-dimensional transpiration, photosynthesis and absorbed radiation model, MAESTRA. MAESTRA predicted species-specific transpiration from the interactions of leaf-level physiology and spatially explicit micro-scale weather patterns in a mixed deciduous hardwood plantation on a 15-min time step. The monthly differences between modeled mean daily transpiration estimates and measured mean daily sap flow ranged from a 35% underestimation for Acer buergeranum in June to a 25% overestimation for A. rubrum in July. The sensitivity of the modeled transpiration estimates was examined across a 30% error range for seven physiological input parameters. The minimum value of stomatal conductance as incident solar radiation tends to zero was determined to be eight times more influential than all other physiological model input parameters. This work quantified the major factors that influence modeled species-specific transpiration and confirmed the ability to scale leaf-level physiological attributes to whole-crown transpiration on a species-specific basis.

Flood risk reduction and flow buffering as ecosystem services - Part 2: Land use and rainfall intensity effects in Southeast Asia

NASA Astrophysics Data System (ADS)

van Noordwijk, Meine; Tanika, Lisa; Lusiana, Betha

2017-05-01

Watersheds buffer the temporal pattern of river flow relative to the temporal pattern of rainfall. This ecosystem service is inherent to geology and climate, but buffering also responds to human use and misuse of the landscape. Buffering can be part of management feedback loops if salient, credible and legitimate indicators are used. The flow persistence parameter Fp in a parsimonious recursive model of river flow (Part 1, van Noordwijk et al., 2017) couples the transmission of extreme rainfall events (1 - Fp), to the annual base-flow fraction of a watershed (Fp). Here we compare Fp estimates from four meso-scale watersheds in Indonesia (Cidanau, Way Besai and Bialo) and Thailand (Mae Chaem), with varying climate, geology and land cover history, at a decadal timescale. The likely response in each of these four to variation in rainfall properties (including the maximum hourly rainfall intensity) and land cover (comparing scenarios with either more or less forest and tree cover than the current situation) was explored through a basic daily water-balance model, GenRiver. This model was calibrated for each site on existing data, before being used for alternative land cover and rainfall parameter settings. In both data and model runs, the wet-season (3-monthly) Fp values were consistently lower than dry-season values for all four sites. Across the four catchments Fp values decreased with increasing annual rainfall, but specific aspects of watersheds, such as the riparian swamp (peat soils) in Cidanau reduced effects of land use change in the upper watershed. Increasing the mean rainfall intensity (at constant monthly totals for rainfall) around the values considered typical for each landscape was predicted to cause a decrease in Fp values by between 0.047 (Bialo) and 0.261 (Mae Chaem). Sensitivity of Fp to changes in land use change plus changes in rainfall intensity depends on other characteristics of the watersheds, and generalisations made on the basis of one or two case studies may not hold, even within the same climatic zone. A wet-season Fp value above 0.7 was achievable in forest-agroforestry mosaic case studies. Inter-annual variability in Fp is large relative to effects of land cover change. Multiple (5-10) years of paired-plot data would generally be needed to reject no-change null hypotheses on the effects of land use change (degradation and restoration). Fp trends over time serve as a holistic scale-dependent performance indicator of degrading/recovering watershed health and can be tested for acceptability and acceptance in a wider social-ecological context.

Updated computations and estimates of streamflows tributary to Carson Valley, Douglas County, Nevada, and Alpine County, California, 1990-2002

USGS Publications Warehouse

Maurer, Douglas K.; Watkins, Sharon A.; Burrowws, Robert L.

2004-01-01

Rapid population growth in Carson Valley has caused concern over the continued availability of water resources to sustain future growth. The U.S. Geological Survey, in cooperation with Douglas County, began a study to update estimates of water-budget components in Carson Valley for current climatic conditions. Data collected at 19 sites included 9 continuous records of tributary streamflows, 1 continuous record of outflow from the valley, and 408 measurements of 10 perennially flowing but ungaged drainages. These data were compiled and analyzed to provide updated computations and estimates of streamflows tributary to Carson Valley, 1990-2002. Mean monthly and annual flows were computed from continuous records for the period 1990-2002 for five streams, and for the period available, 1990-97, for four streams. Daily mean flow from ungaged drainages was estimated using multi-variate regressions of individual discharge measurements against measured flow at selected continuous gages. From the estimated daily mean flows, monthly and annual mean flows were calculated from 1990 to 2002. These values were used to compute estimates of mean monthly and annual flows for the ungaged perennial drainages. Using the computed and estimated mean annual flows, annual unit-area runoff was computed for the perennial drainages, which ranged from 0.30 to 2.02 feet. For the period 1990-2002, estimated inflow of perennial streams tributary to Carson Valley totaled about 25,900 acre-feet per year. Inflow computed from gaged perennial drainages totaled 10,300 acre-feet per year, and estimated inflow from ungaged perennial drainages totaled 15,600 acre-feet per year. The annual flow of perennial streams ranges from 4,210 acre-feet at Clear Creek to 450 acre-feet at Stutler Canyon Creek. Differences in unit-area runoff and in the seasonal timing of flow likely are caused by differences in geologic setting, altitude, slope, or aspect of the individual drainages. The remaining drainages are ephemeral and supply inflow to the valley floor only during spring runoff in wet years or during large precipitation events. Annual unit-area runoff for the perennial drainages was used to estimate inflow from ephemeral drainages totaling 11,700 acre-feet per year. The totaled estimate of perennial and ephemeral tributary inflows to Carson Valley is 37,600 acre-feet per year. Gaged perennial inflow is 27 percent of the total, ungaged perennial inflow is 42 percent, and ephemeral inflow is 31 percent. The estimate is from 50 to 60 percent greater than three previous estimates, one made for a larger area and similar to two other estimates made for larger areas. The combined uncertainty of the estimates totaled about 33 percent of the total inflow or about 12,000 acre-feet per year.

Quantitative identification of riverine nitrogen from point, direct runoff and base flow sources.

PubMed

Huang, Hong; Zhang, Baifa; Lu, Jun

2014-01-01

We present a methodological example for quantifying the contributions of riverine total nitrogen (TN) from point, direct runoff and base flow sources by combining a recursive digital filter technique and statistical methods. First, we separated daily riverine flow into direct runoff and base flow using a recursive digital filter technique; then, a statistical model was established using daily simultaneous data for TN load, direct runoff rate, base flow rate, and temperature; and finally, the TN loading from direct runoff and base flow sources could be inversely estimated. As a case study, this approach was adopted to identify the TN source contributions in Changle River, eastern China. Results showed that, during 2005-2009, the total annual TN input to the river was 1,700.4±250.2 ton, and the contributions of point, direct runoff and base flow sources were 17.8±2.8%, 45.0±3.6%, and 37.2±3.9%, respectively. The innovation of the approach is that the nitrogen from direct runoff and base flow sources could be separately quantified. The approach is simple but detailed enough to take the major factors into account, providing an effective and reliable method for riverine nitrogen loading estimation and source apportionment.

Short-term and long-term evapotranspiration rates at ecological restoration sites along a large river receiving rare flow events

USGS Publications Warehouse

Shanafield, Margaret; Jurado, Hugo Gutierrez; Burgueño, Jesús Eliana Rodríguez; Hernández, Jorge Ramírez; Jarchow, Christopher; Nagler, Pamela L.

2017-01-01

Many large rivers around the world no longer flow to their deltas, due to ever greater water withdrawals and diversions for human needs. However, the importance of riparian ecosystems is drawing increasing recognition, leading to the allocation of environmental flows to restore river processes. Accurate estimates of riparian plant evapotranspiration (ET) are needed to understand how the riverine system responds to these rare events and achieve the goals of environmental flows. In 2014, historic environmental flows were released into the Lower Colorado River at Morelos Dam (Mexico); this once perennial but now dry reach is the final stretch to the mighty Colorado River Delta. One of the primary goals was to supply native vegetation restoration sites along the reach with water to help seedlings establish and boost groundwater levels to foster the planted saplings. Patterns in ET before, during, and after the flows are useful for evaluating whether this goal was met and understanding the role that ET plays in this now ephemeral river system. Here, diurnal fluctuations in groundwater levels and MODIS data were used to compare estimates of ET specifically at three native vegetation restoration sites during 2014 planned flow events, while MODIS data was used to evaluate long-term (2002 – 2016) ET responses to restoration efforts at these sites. Overall, ET was generally 0 - 10 mm d-1 across sites and although daily ET values from groundwater data were highly variable, weekly averaged estimates were highly correlated with MODIS-derived estimates at most sites. The influence of the 2014 flow events was not immediately apparent in the results, although the process of clearing vegetation and planting native vegetation at the restoration sites was clearly visible in the results.

Daily fluctuation of hepatic P450 monooxygenase activities in male rats is controlled by the suprachiasmatic nucleus but remains unaffected by adrenal hormones.

PubMed

Furukawa, T; Manabe, S; Watanabe, T; Sehata, S; Sharyo, S; Okada, T; Mori, Y

1999-09-01

Hepatic P450 monooxygenase activities, which strongly influence the efficacy and/or toxicity of drugs, are known to fluctuate daily. We also know that the P450 activities assessed by measurement of 7-alkoxycoumarin O-dealkylase (ACD) activities fluctuate daily, with apparently high values during the dark period in male rats. However, there is little knowledge about the factors that regulate daily fluctuation of P450 monooxygenase activities. In the present study using rats, we induced lesions in the suprachiasmatic nucleus (SCN) of the brain, the known site of the body's internal clock, and examined the effects on the daily fluctuation of the ACD activities to clarify the relationship between the SCN and the daily fluctuation of P450 monooxygenase activities. In addition, adrenalectomy was performed to re-evaluate the influence of adrenal hormones on the P450 activities. Our results indicated that daily fluctuations of the hepatic ACD activities were completely eliminated in the SCN-lesioned rats. However, the ACD activities in the adrenalectomized rats showed apparent daily fluctuations with high values during the dark period and low values during the light period. Therefore, this study demonstrated that the daily fluctuation of the hepatic P450 monooxygenase activities in male rats is controlled by the SCN but remains unaffected by the adrenal hormones.

40 CFR 65.162 - Nonflare control and recovery device monitoring records.

Code of Federal Regulations, 2010 CFR

2010-07-01

...). For catalytic incinerators, record the daily average of the temperature upstream of the catalyst bed and the daily average of the temperature differential across the bed. For halogen scrubbers, record... regeneration stream flow and carbon bed regeneration temperature are monitored, the following records shall be...

40 CFR Table 2 to Subpart Nnnnn of... - Operating Limits

Code of Federal Regulations, 2011 CFR

2011-07-01

... vented to a control device. For each . . . You must . . . 1. Caustic scrubber or water scrubber/absorber a. Maintain the daily average scrubber inlet liquid or recirculating liquid flow rate, as appropriate, above the operating limit; andb. Maintain the daily average scrubber effluent pH within the...

40 CFR Table 2 to Subpart Nnnnn of... - Operating Limits

Code of Federal Regulations, 2010 CFR

2010-07-01

... vented to a control device. For each . . . You must . . . 1. Caustic scrubber or water scrubber/absorber a. Maintain the daily average scrubber inlet liquid or recirculating liquid flow rate, as appropriate, above the operating limit; andb. Maintain the daily average scrubber effluent pH within the...

Surface waters of Illinois River basin in Arkansas and Oklahoma

USGS Publications Warehouse

Laine, L.L.

1959-01-01

The estimated runoff from the Illinois River basin of 1,660 square miles has averaged 1,160,000 acre-feet per year during the water years 1938-56, equivalent to an average annual runoff depth of 13.1 inches. About 47 percent of the streamflow is contributed from drainage in Arkansas, where an average of 550,000 acre-ft per year runs off from 755 square miles, 45.5 percent of the total drainage area. The streamflow is highly variable. Twenty-two years of record for Illinois River near Tahlequah, Okla., shows a variation in runoff for the water year 1945 in comparison with 1954 in a ratio of almost 10 to 1. Runoff in 1927 may have exceeded that of 1945, according to records for White River at Beaver, Ark., the drainage basin just east of the Illinois River basin. Variation in daily discharge is suggested by a frequency analysis of low flows at the gaging station near Tahlequah, Okla. The mean flow at that site is 901 cfs (cubic feet per second), the median daily flow is 350 cfs, and the lowest 30-day mean flow in a year probably will be less than 130 cfs half of the time and less than 20 cfs every 10 years on the average. The higher runoff tends to occur in the spring months, March to May, a 3-month period that, on the average, accounts for almost half of the annual flow. High runoff may occur during any month in the year, but in general, the streamflow is the lowest in the summer. The mean monthly flow of Illinois River near Tahlequah, Okla., for September is about 11 percent of that for May. Records show that there is flow throughout the year in Illinois River and its principal tributaries Osage Creek, Flint Creek and Barren Fork. The high variability in streamflow in this region requires the development of storage by impoundment if maximum utilization of the available water supplies is to be attained. For example, a 120-day average low flow of 22 cfs occurred in 1954 at Illinois River near Tahlequah, Okla. To have maintained the flow at 350 cfs, the median daily flow during the 19-year base period, an impoundment at that site would have required a usable storage of 185,000 acre-ft to satisfy this demand during the drought years 1954-1956. The surface waters of the Illinois River basin are excellent quality being suitable for municipal, agriculture and most industrial uses. The average concentration of the dissolved mineral content is about 105 ppm (parts per million) and the hardness about 85 ppm. The water is slightly alkaline, having a range of pH values from 7.2 to 8.0. This report gives the estimated average discharge at gaging stations and approximations of average discharge at the State line for 3 sub-basins during the 19-year period October 1937 to September 1956, used as a base period in this report. Duration-of-flow data for various percentages of the time are shown for the period of observed record at the gaging stations; similar data are estimated for the selected base period. Storage requirements to sustain flow during the recent drought years are given for 3 stations. The streamflow records in the basin are presented on a monthly and annual basis through September 1957; provisional records for 3 stations are included through July 1958 for correlation purposes. Results of discharge measurements are given for miscellaneous sites where low-flow observations have been made. (available as photostat copy only)

Estimation of shallow ground-water recharge in the Great Lakes basin

USGS Publications Warehouse

Neff, B.P.; Piggott, A.R.; Sheets, R.A.

2006-01-01

This report presents the results of the first known integrated study of long-term average ground-water recharge to shallow aquifers (generally less than 100 feet deep) in the United States and Canada for the Great Lakes, upper St. Lawrence, and Ottawa River Basins. The approach used was consistent throughout the study area and allows direct comparison of recharge rates in disparate parts of the study area. Estimates of recharge are based on base-flow estimates for streams throughout the Great Lakes Basin and the assumption that base flow in a given stream is equal to the amount of shallow ground-water recharge to the surrounding watershed, minus losses to evapotranspiration. Base-flow estimates were developed throughout the study area using a single model based on an empirical relation between measured base-flow characteristics at streamflow-gaging stations and the surficial-geologic materials, which consist of bedrock, coarse-textured deposits, fine-textured deposits, till, and organic matter, in the surrounding surface-water watershed. Model calibration was performed using base-flow index (BFI) estimates for 959 stations in the U.S. and Canada using a combined 28,784 years of daily streamflow record determined using the hydrograph-separation software program PART. Results are presented for watersheds represented by 8-digit hydrologic unit code (HUC, U.S.) and tertiary (Canada) watersheds. Recharge values were lowest (1.6-4.0 inches/year) in the eastern Lower Peninsula of Michigan; southwest of Green Bay, Wisconsin; in northwestern Ohio; and immediately south of the St. Lawrence River northeast of Lake Ontario. Recharge values were highest (12-16.8 inches/year) in snow shadow areas east and southeast of each Great Lake. Further studies of deep aquifer recharge and the temporal variability of recharge would be needed to gain a more complete understanding of ground-water recharge in the Great Lakes Basin.

75 FR 68736 - Approval of One-Year Extension for Attaining the 1997 8-Hour Ozone Standard for the Delaware...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-11-09

... 4th highest daily 8-hour monitored ozone value during the 2009 ozone season is 0.084 parts per million... extensions of the attainment date if: (a) For the first 1-year extension, the area's 4th highest daily 8...'s 4th highest daily 8-hour value, averaged over both the original attainment year and the first...

Rethinking physical activity communication: using focus groups to understand women's goals, values, and beliefs to improve public health.

PubMed

Segar, Michelle; Taber, Jennifer M; Patrick, Heather; Thai, Chan L; Oh, April

2017-05-18

Communication about physical activity (PA) frames PA and influences what it means to people, including the role it plays in their lives. To the extent that PA messages can be designed to reflect outcomes that are relevant to what people most value experiencing and achieving in their daily lives, the more compelling and effective they will be. Aligned with self-determination theory, this study investigated proximal goals and values that are salient in everyday life and how they could be leveraged through new messaging to better support PA participation among women. The present study was designed to examine the nature of women's daily goals and priorities and investigate women's PA beliefs, feelings, and experiences, in order to identify how PA may compete with or facilitate women's daily goals and priorities. Preliminary recommendations are proposed for designing new PA messages that align PA with women's daily goals and desired experiences to better motivate participation. Eight focus groups were conducted with White, Black, and Hispanic/Latina women aged 22-49, stratified by amount of self-reported PA (29 low active participants, 11 high active participants). Respondents discussed their goals, values, and daily priorities along with beliefs, feelings about and experiences being physically active. Data were collected, coded, and analyzed using a thematic analysis strategy to identify emergent themes. Many of the goals and values that both low and high active participants discussed as desiring and valuing map on to key principles of self-determination theory. However, the discussions among low active participants suggested that their beliefs, feelings, experiences, and definitions of PA were in conflict with their proximal goals, values, and priorities, also undermining their psychological needs for autonomy, competence, and relatedness. Findings from this study can be used to inform and evaluate new physical activity communication strategies that leverage more proximal goals, values, and experiences of happiness and success to better motivate PA among ethnically diverse low active women. Specifically, this research suggests a need to address how women's daily goals and desired experiences may undermine PA participation, in addition to framing PA as facilitating rather than competing with their daily priorities and desired leisure-time experiences.

Comparison of microbial fermentation of high- and low-forage diets in Rusitec, single-flow continuous-culture fermenters and sheep rumen.

PubMed

Carro, M D; Ranilla, M J; Martín-García, A I; Molina-Alcaide, E

2009-04-01

Eight Rusitec and eight single-flow continuous-culture fermenters (SFCCF) were used to compare the ruminal fermentation of two diets composed of alfalfa hay and concentrate in proportions of 80 : 20 (F80) and 20 : 80 (F20). Results were validated with those obtained previously in sheep fed the same diets. Rusitec fermenters were fed once daily and SFCCF twice, but liquid dilution rates were similar in both types of fermenters. Mean values of pH over the 12 h postfeeding were higher (P < 0.001) in Rusitec than in SFCCF, with diet F80 showing higher values (P < 0.001) in both types of fermenters. Concentrations of total volatile fatty acids (VFA) were higher (P < 0.001) in SFCCF than in Rusitec, and in both systems were higher (P = 0.002) for diet F20 than for diet F80. There were significant differences between systems in the proportions of the main VFA, and a fermentation system × diet interaction (P < 0.001) was detected for all VFA with the exception of valerate. No differences (P = 0.145) between the two types of fermenters were detected in dry matter (DM) digestibility, but NDF, microbial N flow and its efficiency were higher (P = 0.001) in SFCCF compared to Rusitec. Whereas pH values and VFA concentrations remained fairly stable through the day in both in vitro systems, pH dropped and VFA increased shortly after feeding in sheep rumen reaching the minimum and maximal values, respectively, about 4 h after feeding. Both in vitro systems detected differences between diets similar to those found in sheep for liquid dilution rate, pH values, DM digestibility, microbial N flow and growth efficiency. In contrast, acetate/propionate ratios were lower for diet F20 than for F80 in sheep rumen (2.73 and 3.97) and SFCCF (3.07 and 4.80), but were higher for diet F20 compared to F80 (4.29 and 3.40) in Rusitec, with values considered to be unphysiological for high-concentrate diets. In vivo NDF digestibility was affected (P = 0.017) by diet, but no differences between diets (P > 0.05) were found in any in vitro system. A more precise control of pH in both types of fermenters and a reduction of concentrate retention time in Rusitec could probably improve the simulation of in vivo fermentation.

Combination of radar and daily precipitation data to estimate meaningful sub-daily point precipitation extremes

NASA Astrophysics Data System (ADS)

Bárdossy, András; Pegram, Geoffrey

2017-01-01

The use of radar measurements for the space time estimation of precipitation has for many decades been a central topic in hydro-meteorology. In this paper we are interested specifically in daily and sub-daily extreme values of precipitation at gauged or ungauged locations which are important for design. The purpose of the paper is to develop a methodology to combine daily precipitation observations and radar measurements to estimate sub-daily extremes at point locations. Radar data corrected using precipitation-reflectivity relationships lead to biased estimations of extremes. Different possibilities of correcting systematic errors using the daily observations are investigated. Observed gauged daily amounts are interpolated to unsampled points and subsequently disaggregated using the sub-daily values obtained by the radar. Different corrections based on the spatial variability and the subdaily entropy of scaled rainfall distributions are used to provide unbiased corrections of short duration extremes. Additionally a statistical procedure not based on a matching day by day correction is tested. In this last procedure as we are only interested in rare extremes, low to medium values of rainfall depth were neglected leaving a small number of L days of ranked daily maxima in each set per year, whose sum typically comprises about 50% of each annual rainfall total. The sum of these L day maxima is first iterpolated using a Kriging procedure. Subsequently this sum is disaggregated to daily values using a nearest neighbour procedure. The daily sums are then disaggregated by using the relative values of the biggest L radar based days. Of course, the timings of radar and gauge maxima can be different, so the method presented here uses radar for disaggregating daily gauge totals down to 15 min intervals in order to extract the maxima of sub-hourly through to daily rainfall. The methodologies were tested in South Africa, where an S-band radar operated relatively continuously at Bethlehem from 1998 to 2003, whose scan at 1.5 km above ground [CAPPI] overlapped a dense (10 km spacing) set of 45 pluviometers recording in the same 6-year period. This valuable set of data was obtained from each of 37 selected radar pixels [1 km square in plan] which contained a pluviometer not masked out by the radar foot-print. The pluviometer data were also aggregated to daily totals, for the same purpose. The extremes obtained using disaggregation methods were compared to the observed extremes in a cross validation procedure. The unusual and novel goal was not to obtain the reproduction of the precipitation matching in space and time, but to obtain frequency distributions of the point extremes, which we found to be stable.

Extrapolating regional probability of drying of headwater streams using discrete observations and gauging networks

NASA Astrophysics Data System (ADS)

Beaufort, Aurélien; Lamouroux, Nicolas; Pella, Hervé; Datry, Thibault; Sauquet, Eric

2018-05-01

Headwater streams represent a substantial proportion of river systems and many of them have intermittent flows due to their upstream position in the network. These intermittent rivers and ephemeral streams have recently seen a marked increase in interest, especially to assess the impact of drying on aquatic ecosystems. The objective of this paper is to quantify how discrete (in space and time) field observations of flow intermittence help to extrapolate over time the daily probability of drying (defined at the regional scale). Two empirical models based on linear or logistic regressions have been developed to predict the daily probability of intermittence at the regional scale across France. Explanatory variables were derived from available daily discharge and groundwater-level data of a dense gauging/piezometer network, and models were calibrated using discrete series of field observations of flow intermittence. The robustness of the models was tested using an independent, dense regional dataset of intermittence observations and observations of the year 2017 excluded from the calibration. The resulting models were used to extrapolate the daily regional probability of drying in France: (i) over the period 2011-2017 to identify the regions most affected by flow intermittence; (ii) over the period 1989-2017, using a reduced input dataset, to analyse temporal variability of flow intermittence at the national level. The two empirical regression models performed equally well between 2011 and 2017. The accuracy of predictions depended on the number of continuous gauging/piezometer stations and intermittence observations available to calibrate the regressions. Regions with the highest performance were located in sedimentary plains, where the monitoring network was dense and where the regional probability of drying was the highest. Conversely, the worst performances were obtained in mountainous regions. Finally, temporal projections (1989-2016) suggested the highest probabilities of intermittence (> 35 %) in 1989-1991, 2003 and 2005. A high density of intermittence observations improved the information provided by gauging stations and piezometers to extrapolate the temporal variability of intermittent rivers and ephemeral streams.

An analysis of potential water availability from the Atwood, Leesville, and Tappan Lakes in the Muskingum River Watershed, Ohio

USGS Publications Warehouse

Koltun, G.F.

2013-01-01

This report presents the results of a study to assess potential water availability from the Atwood, Leesville, and Tappan Lakes, located within the Muskingum River Watershed, Ohio. The assessment was based on the criterion that water withdrawals should not appreciably affect maintenance of recreation-season pool levels in current use. To facilitate and simplify the assessment, it was assumed that historical lake operations were successful in maintaining seasonal pool levels, and that any discharges from lakes constituted either water that was discharged to prevent exceeding seasonal pool levels or discharges intended to meet minimum in-stream flow targets downstream from the lakes. It further was assumed that the volume of water discharged in excess of the minimum in-stream flow target is available for use without negatively impacting seasonal pool levels or downstream water uses and that all or part of it is subject to withdrawal. Historical daily outflow data for the lakes were used to determine the quantity of water that potentially could be withdrawn and the resulting quantity of water that would flow downstream (referred to as “flow-by”) on a daily basis as a function of all combinations of three hypothetical target minimum flow-by amounts (1, 2, and 3 times current minimum in-stream flow targets) and three pumping capacities (1, 2, and 3 million gallons per day). Using both U.S. Geological Survey streamgage data and lake-outflow data provided by the U.S. Army Corps of Engineers resulted in analytical periods ranging from 51 calendar years for the Atwood Lake to 73 calendar years for the Leesville and Tappan Lakes. The observed outflow time series and the computed time series of daily flow-by amounts and potential withdrawals were analyzed to compute and report order statistics (95th, 75th, 50th, 25th, 10th, and 5th percentiles) and means for the analytical period, in aggregate, and broken down by calendar month. In addition, surplus-water mass curve data were tabulated for each of the lakes. Monthly order statistics of computed withdrawals indicated that, for the three pumping capacities considered, increasing the target minimum flow-by amount tended to reduce the amount of water that can be withdrawn. The reduction was greatest in the lower percentiles of withdrawal; however, increasing the flow-by amount had no impact on potential withdrawals during high flow. In addition, for a given target minimum flow-by amount, increasing the pumping rate increased the total amount of water that could be withdrawn; however, that increase was less than a direct multiple of the increase in pumping rate for most flow statistics. Potential monthly withdrawals were observed to be more variable and more limited in some calendar months than others. Monthly order statistics and means of computed daily mean flow-by amounts indicated that flow-by amounts generally tended to be lowest during June–October and February. Increasing the target minimum flow-by amount for a given pumping rate resulted in some small increases in the magnitudes of the mean and 50th percentile and lower order statistics of computed mean flow-by, but had no effect on the magnitudes of the higher percentile statistics. Increasing the pumping rate for a given target minimum flow-by amount resulted in decreases in magnitudes of higher-percentile flow-by statistics by an amount equal to the flow equivalent of the increase in pumping rate; however, some lower percentile statistics remained unchanged.

Regional regression equations for the estimation of selected monthly low-flow duration and frequency statistics at ungaged sites on streams in New Jersey

USGS Publications Warehouse

Watson, Kara M.; McHugh, Amy R.

2014-01-01

Regional regression equations were developed for estimating monthly flow-duration and monthly low-flow frequency statistics for ungaged streams in Coastal Plain and non-coastal regions of New Jersey for baseline and current land- and water-use conditions. The equations were developed to estimate 87 different streamflow statistics, which include the monthly 99-, 90-, 85-, 75-, 50-, and 25-percentile flow-durations of the minimum 1-day daily flow; the August–September 99-, 90-, and 75-percentile minimum 1-day daily flow; and the monthly 7-day, 10-year (M7D10Y) low-flow frequency. These 87 streamflow statistics were computed for 41 continuous-record streamflow-gaging stations (streamgages) with 20 or more years of record and 167 low-flow partial-record stations in New Jersey with 10 or more streamflow measurements. The regression analyses used to develop equations to estimate selected streamflow statistics were performed by testing the relation between flow-duration statistics and low-flow frequency statistics for 32 basin characteristics (physical characteristics, land use, surficial geology, and climate) at the 41 streamgages and 167 low-flow partial-record stations. The regression analyses determined drainage area, soil permeability, average April precipitation, average June precipitation, and percent storage (water bodies and wetlands) were the significant explanatory variables for estimating the selected flow-duration and low-flow frequency statistics. Streamflow estimates were computed for two land- and water-use conditions in New Jersey—land- and water-use during the baseline period of record (defined as the years a streamgage had little to no change in development and water use) and current land- and water-use conditions (1989–2008)—for each selected station using data collected through water year 2008. The baseline period of record is representative of a period when the basin was unaffected by change in development. The current period is representative of the increased development of the last 20 years (1989–2008). The two different land- and water-use conditions were used as surrogates for development to determine whether there have been changes in low-flow statistics as a result of changes in development over time. The State was divided into two low-flow regression regions, the Coastal Plain and the non-coastal region, in order to improve the accuracy of the regression equations. The left-censored parametric survival regression method was used for the analyses to account for streamgages and partial-record stations that had zero flow values for some of the statistics. The average standard error of estimate for the 348 regression equations ranged from 16 to 340 percent. These regression equations and basin characteristics are presented in the U.S. Geological Survey (USGS) StreamStats Web-based geographic information system application. This tool allows users to click on an ungaged site on a stream in New Jersey and get the estimated flow-duration and low-flow frequency statistics. Additionally, the user can click on a streamgage or partial-record station and get the “at-site” streamflow statistics. The low-flow characteristics of a stream ultimately affect the use of the stream by humans. Specific information on the low-flow characteristics of streams is essential to water managers who deal with problems related to municipal and industrial water supply, fish and wildlife conservation, and dilution of wastewater.

Hydrologic Evaluation of TRMM Multisatellite Precipitation Analysis for Nanliu River Basin in Humid Southwestern China.

PubMed

Zhao, Yinjun; Xie, Qiongying; Lu, Yuan; Hu, Baoqing

2017-06-01

The accuracy of Tropical Rainfall Measuring Mission (TRMM) multi-satellite precipitation analysis (TMPA) daily accumulated precipitation products (3B42RTV7 and 3B42V7) was evaluated for a small basin (the Nanliu river basin). A direct comparison was performed against gauge observations from a period of 9 years (2000-2009) at temporal and spatial scales. The results show that the temporal-spatial precipitation characteristics of the Nanliu river basin are highly consistent with 3B42V7 relative to 3B42RTV7, with higher correlation coefficient (CC) approximately 0.9 at all temporal scales except for the daily scale and a lower relative bias percentage. 3B42V7 slightly overestimates precipitation at all temporal scales except the yearly scale; it slightly underestimates the precipitation at the daily spatial scale. The results also reveal that the precision of TMPA products increases with longer time-aggregated data, and the detection capability of daily TMPA precipitation products are enhanced by augmentation with daily precipitation rates. In addition, daily TMPA products were input into the Xin'anjiang hydrologic model; the results show that 3B42V7-based simulated outputs were well in line with actual stream flow observations, with a high CC (0.90) and Nash-Sutcliffe efficiency coefficient (NSE, 0.79), and the results adequately captured the pattern of the observed flow curve.

Assessing the ecological base flow in an experimental watershed of Central Taiwan

NASA Astrophysics Data System (ADS)

Wei, Chiang; Yang, Ping-Shih; Tian, Pei-Ling

2010-05-01

The ecological base flow is crucial for the assessment and design for habitat rehabilitation and recovery. The amount of discharge affects the aquatic creatures and may damage the existence and balance of the community under extreme low conditions. Aquatic insect is selected as the target species in this study to evaluate the influence of the discharge and to estimate the ecological base flow. The distribution of the number of species and abundance (density) versus discharge is assessed to define the critical discharge. A stream located at the alpine area in central Taiwan is selected as the study area to evaluate the base flow. From the preliminary data (Aug 2008 to May 2009) collected from Creek C of Sitou watershed (area: 1.3 km^2) shows that the abundance of several species varies with the discharge. The dominate family and genus of aquatic insects is Baetidae (Order Ephemeroptera) and Baetis spp. that accounts for 26.3 and 17.2 %, respectively. The Hilsenhoff family biotic index (FBI) shows that the water quality is classified to "Excellent" and "Good" level while the EPT Index (Index of three orders: Ephemeroptera, Plecoptera, and Trichoptera) indicates that the stream is non-polluted. The discharge of base flow interpreted from the 90%, 95% and 96% curve of duration for the daily discharge is 0.1582, 0.0476 and 0.0378 cms; the threshold value evaluated by curve of abundance vs. discharge is 0.0154 cms. Consistent observations are yet to be collected to yield more accurate results.

Development and comparison of Bayesian modularization method in uncertainty assessment of hydrological models

NASA Astrophysics Data System (ADS)

Li, L.; Xu, C.-Y.; Engeland, K.

2012-04-01

With respect to model calibration, parameter estimation and analysis of uncertainty sources, different approaches have been used in hydrological models. Bayesian method is one of the most widely used methods for uncertainty assessment of hydrological models, which incorporates different sources of information into a single analysis through Bayesian theorem. However, none of these applications can well treat the uncertainty in extreme flows of hydrological models' simulations. This study proposes a Bayesian modularization method approach in uncertainty assessment of conceptual hydrological models by considering the extreme flows. It includes a comprehensive comparison and evaluation of uncertainty assessments by a new Bayesian modularization method approach and traditional Bayesian models using the Metropolis Hasting (MH) algorithm with the daily hydrological model WASMOD. Three likelihood functions are used in combination with traditional Bayesian: the AR (1) plus Normal and time period independent model (Model 1), the AR (1) plus Normal and time period dependent model (Model 2) and the AR (1) plus multi-normal model (Model 3). The results reveal that (1) the simulations derived from Bayesian modularization method are more accurate with the highest Nash-Sutcliffe efficiency value, and (2) the Bayesian modularization method performs best in uncertainty estimates of entire flows and in terms of the application and computational efficiency. The study thus introduces a new approach for reducing the extreme flow's effect on the discharge uncertainty assessment of hydrological models via Bayesian. Keywords: extreme flow, uncertainty assessment, Bayesian modularization, hydrological model, WASMOD

Potential effects of four Flaming Gorge Dam hydropower operational scenarios on the fishes of the Green River, Utah and Colorado

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hlohowskyj, I.; Hayse, J.W.

1995-09-01

Aerial videography and modeling were used to evaluate the impacts of four hydropower operational scenarios at Flaming Gorge Dam, Utah, on trout and native fishes in the Green River, Utah and Colorado. The four operational scenarios studied were year-round high fluctuations, seasonally adjusted high fluctuations, seasonally adjusted moderate fluctuations, and seasonally adjusted steady flows. Impacts on trout were evaluated by examining differences among scenarios in the areas of inundated substrates that serve as spawning and feeding habitat. All scenarios would provide at least 23 acres per mile of habitat for spawning and food production; seasonally adjusted operations would provide additionalmore » areas during periods of sustained high release. Seasonally adjusted high fluctuations would increase inundated areas by 12 to 26% for a short period in winter and spring, but food production and reproduction would not be expected to increase. Seasonally adjusted moderate fluctuations and steady flows would produce similar increases in area, but the longer period of inundation could also result in increased food production and provide additional spawning sites for trout. Impacts on native fishes were assessed by examining daily changes in backwater nursery areas. Compared with year-round high fluctuations, the daily changes in backwater area would decrease by about 47, 89, and 100% under the seasonally adjusted high fluctuation, moderate fluctuation, and steady flow scenarios, respectively. Similarly, daily stage fluctuations during the nursery period would decrease by 72, 89, and 100% under the seasonally adjusted high fluctuation, moderate fluctuation, and steady flow scenarios, respectively. These reductions in daily fluctuations in backwater area and stage would improve conditions in nursery habitats and could in turn improve recruitment and overwinter survival. Introduced fish species could also benefit from the seasonally adjusted operational scenarios.« less

Effect of Isometric Hand Grip Exercises on Blood Flow and Placement of IV Catheters for Administration of Chemotherapy.

PubMed

Ozkaraman, Ayse; Yesilbalkan, Öznur Usta

2016-04-01

Complications may occur in the subcutaneous or subdermal tissues during IV administration of chemotherapy related to blood flow and catheter placement. Daily isometric hand grip exercises were evaluated for their effect on blood flow in the vessels of the nondominant arm before placement of IV catheters and the success rate of IV catheter placement on the first attempt. The study focused on patients with non-Hodgkin lymphoma receiving the first and second cycles of chemotherapy. The intervention group performed daily isometric hand grip exercises before chemotherapy with peripheral catheter insertion. The control group performed routine activities only. Blood flow was measured by ultrasound in the brachial artery (BA) and brachial vein (BV) of the nondominant arm before the first (T1) and second (T2) cycles of chemotherapy. Blood flow slightly increased in the intervention group at T2 compared to T1. In the control group, blood flow decreased in the BA and did not change in the BV at T2 compared to T1. The success rate for first-attempt placement of a peripheral IV catheter was the same for the intervention and control groups.

Modeling and monitoring cyclic and linear volatile methylsiloxanes in a wastewater treatment plant using constant water level sequencing batch reactors.

PubMed

Wang, De-Gao; Du, Juan; Pei, Wei; Liu, Yongjun; Guo, Mingxing

2015-04-15

The fate of cyclic and linear volatile methylsiloxanes (VMSs) was evaluated in a wastewater treatment plant (WWTP) using constant water level sequencing batch reactors from Dalian, China. Influent, effluent, and sewage sludge samples were collected for seven consecutive days. The mean concentrations of cyclic VMSs (cVMSs) in influent and effluent samples are 1.05 μg L(-1) and 0.343 μg L(-1); the total removal efficiency of VMSs is >60%. Linear VMS (lVMS) concentration is under the quantification limitation in aquatic samples but is found in sludge samples with a value of 90 μg kg(-1). High solid-water partition coefficients result in high VMS concentrations in sludge with the mean value of 5030 μg kg(-1). No significant differences of the daily mass flows are found when comparing the concentration during the weekend and during working days. The estimated mass load of total cVMSs is 194 mg d(-1)1000 inhabitants(-1) derived for the population. A mass balance model of the WWTP was developed and derived to simulate the fate of cVMSs. The removal by sorption on sludge increases, and the volatilization decreases with increasing hydrophobicity and decreasing volatility for cVMSs. Sensitivity analysis shows that the total suspended solid concentration in the effluent, mixed liquor suspended solid concentration, the sewage sludge flow rate, and the influent flow rate are the most influential parameters on the mass distribution of cVMSs in this WWTP. Copyright © 2015 Elsevier B.V. All rights reserved.

Use of flow-normalization to evaluate nutrient concentration and flux changes in Lake Champlain tributaries, 1990-2009

USGS Publications Warehouse

Medalie, Laura; Hirsch, Robert M.; Archfield, Stacey A.

2012-01-01

The U.S. Geological Survey evaluated 20 years of total phosphorus (P) and total nitrogen (N) concentration data for 18 Lake Champlain tributaries using a new statistical method based on weighted regressions to estimate daily concentration and flux histories based on discharge, season, and trend as explanatory variables. The use of all the streamflow discharge values for a given date in the record, in a process called "flow-normalization," removed the year-to-year variation due to streamflow and generated a smooth time series from which trends were calculated. This approach to data analysis can be of great value to evaluations of the success of restoration efforts because it filters out the large random fluctuations in the flux that are due to the temporal variability in streamflow. Results for the full 20 years of record showed a mixture of upward and downward trends for concentrations and yields of P and N. When the record was broken into two 10-year periods, for many tributaries, the more recent period showed a reversal in N from upward to downward trends and a similar reversal or reduction in magnitude of upward trends for P. Some measures of P and N concentrations and yields appear to be related to intensity of agricultural activities, point-source loads of P, or population density. Total flow-normalized P flux aggregated from the monitored tributaries showed a decrease of 30 metric tons per year from 1991 to 2009, which is about 15% of the targeted reduction established by the operational management plan for the Lake Champlain Basin.

Special features of the dayCent modeling package and additional procedures for parameterization, calibration, validation, and applications

USDA-ARS?s Scientific Manuscript database

DayCent (Daily Century) is a biogeochemical model of intermediate complexity used to simulate flows of carbon and nutrients for crop, grassland, forest, and savanna ecosystems. Required model inputs are: soil texture, current and historical land use, vegetation cover, and daily maximum/minimum tempe...

Impacts of calibration strategies and ensemble methods on ensemble flood forecasting over Lanjiang basin, Southeast China

NASA Astrophysics Data System (ADS)

Liu, Li; Xu, Yue-Ping

2017-04-01

Ensemble flood forecasting driven by numerical weather prediction products is becoming more commonly used in operational flood forecasting applications.In this study, a hydrological ensemble flood forecasting system based on Variable Infiltration Capacity (VIC) model and quantitative precipitation forecasts from TIGGE dataset is constructed for Lanjiang Basin, Southeast China. The impacts of calibration strategies and ensemble methods on the performance of the system are then evaluated.The hydrological model is optimized by parallel programmed ɛ-NSGAII multi-objective algorithm and two respectively parameterized models are determined to simulate daily flows and peak flows coupled with a modular approach.The results indicatethat the ɛ-NSGAII algorithm permits more efficient optimization and rational determination on parameter setting.It is demonstrated that the multimodel ensemble streamflow mean have better skills than the best singlemodel ensemble mean (ECMWF) and the multimodel ensembles weighted on members and skill scores outperform other multimodel ensembles. For typical flood event, it is proved that the flood can be predicted 3-4 days in advance, but the flows in rising limb can be captured with only 1-2 days ahead due to the flash feature. With respect to peak flows selected by Peaks Over Threshold approach, the ensemble means from either singlemodel or multimodels are generally underestimated as the extreme values are smoothed out by ensemble process.

Combination of radar and daily precipitation data to estimate meaningful sub-daily point precipitation extremes

NASA Astrophysics Data System (ADS)

Pegram, Geoff; Bardossy, Andras; Sinclair, Scott

2017-04-01

The use of radar measurements for the space time estimation of precipitation has for many decades been a central topic in hydro-meteorology. In this presentation we are interested specifically in daily and sub-daily extreme values of precipitation at gauged or ungauged locations which are important for design. The purpose of the presentation is to develop a methodology to combine daily precipitation observations and radar measurements to estimate sub-daily extremes at point locations. Radar data corrected using precipitation-reflectivity relationships lead to biased estimations of extremes. Different possibilities of correcting systematic errors using the daily observations are investigated. Observed gauged daily amounts are interpolated to un-sampled points and subsequently disaggregated using the sub-daily values obtained by the radar. Different corrections based on the spatial variability and the sub-daily entropy of scaled rainfall distributions are used to provide unbiased corrections of short duration extremes. In addition, a statistical procedure not based on a matching day by day correction is tested. In this last procedure, as we are only interested in rare extremes, low to medium values of rainfall depth were neglected leaving 12 days of ranked daily maxima in each set per year, whose sum typically comprises about 50% of each annual rainfall total. The sum of these 12 day maxima is first interpolated using a Kriging procedure. Subsequently this sum is disaggregated to daily values using a nearest neighbour procedure. The daily sums are then disaggregated by using the relative values of the biggest 12 radar based days in each year. Of course, the timings of radar and gauge maxima can be different, so the new method presented here uses radar for disaggregating daily gauge totals down to 15 min intervals in order to extract the maxima of sub-hourly through to daily rainfall. The methodologies were tested in South Africa, where an S-band radar operated relatively continuously at Bethlehem from 1998 to 2003, whose scan at 1.5 km above ground [CAPPI] overlapped a dense [10 km spacing] set of 45 pluviometers recording in the same 6-year period. This valuable set of data was obtained from each of 37 selected radar pixels [1 km square in plan] which contained a pluviometer, not masked out by the radar foot-print. The pluviometer data were also aggregated to daily totals, for the same purpose. The extremes obtained using disaggregation methods were compared to the observed extremes in a cross validation procedure. The unusual and novel goal was not to obtain the reproduction of the precipitation matching in space and time, but to obtain frequency distributions of the point extremes, which we found to be stable. Published as: Bárdossy, A., and G. G. S. Pegram (2017) Journal of Hydrology, Volume 544, pp 397-406

Hypnosis as an adjunct therapy for asthma: case report.

PubMed

Neinstein, L S; Dash, J

1982-08-01

This study reports the effect of hypnotherapy in an asthmatic. The patient had moderately severe asthma with frequent attacks despite multiple medications. He received four weekly hypnosis sessions, and was then followed bimonthly for a year. The patient's course was followed by subjective daily scoring of wheezing severity, daily recording of peak expiratory flow rate by a Wright minispirometer, and once a month recording of his Forced Vital Capacity (FVC), Forced Expiratory Volume in one second/Forced Rate (MMRF). The severity rating showed improvement at one year when the start of therapy was compared to pretherapy (P less than .005). The daily peak flow rate averaged 486 liter/min before starting hypnotherapy and 502 liter/min after one year. There was no charge in the FEV1/FVC and MMFR before and after therapy. School attendance and academic performance may be a helpful adjunct in asthma therapy during adolescence.

DFLOW USER'S MANUAL

EPA Science Inventory

DFLOW is a computer program for estimating design stream flows for use in water quality studies. The manual describes the use of the program on both the EPA's IBM mainframe system and on a personal computer (PC). The mainframe version of DFLOW can extract a river's daily flow rec...

Low-flow characteristics of Virginia streams

USGS Publications Warehouse

Austin, Samuel H.; Krstolic, Jennifer L.; Wiegand, Ute

2011-01-01

Low-flow annual non-exceedance probabilities (ANEP), called probability-percent chance (P-percent chance) flow estimates, regional regression equations, and transfer methods are provided describing the low-flow characteristics of Virginia streams. Statistical methods are used to evaluate streamflow data. Analysis of Virginia streamflow data collected from 1895 through 2007 is summarized. Methods are provided for estimating low-flow characteristics of gaged and ungaged streams. The 1-, 4-, 7-, and 30-day average streamgaging station low-flow characteristics for 290 long-term, continuous-record, streamgaging stations are determined, adjusted for instances of zero flow using a conditional probability adjustment method, and presented for non-exceedance probabilities of 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.3, 0.2, 0.1, 0.05, 0.02, 0.01, and 0.005. Stream basin characteristics computed using spatial data and a geographic information system are used as explanatory variables in regional regression equations to estimate annual non-exceedance probabilities at gaged and ungaged sites and are summarized for 290 long-term, continuous-record streamgaging stations, 136 short-term, continuous-record streamgaging stations, and 613 partial-record streamgaging stations. Regional regression equations for six physiographic regions use basin characteristics to estimate 1-, 4-, 7-, and 30-day average low-flow annual non-exceedance probabilities at gaged and ungaged sites. Weighted low-flow values that combine computed streamgaging station low-flow characteristics and annual non-exceedance probabilities from regional regression equations provide improved low-flow estimates. Regression equations developed using the Maintenance of Variance with Extension (MOVE.1) method describe the line of organic correlation (LOC) with an appropriate index site for low-flow characteristics at 136 short-term, continuous-record streamgaging stations and 613 partial-record streamgaging stations. Monthly streamflow statistics computed on the individual daily mean streamflows of selected continuous-record streamgaging stations and curves describing flow-duration are presented. Text, figures, and lists are provided summarizing low-flow estimates, selected low-flow sites, delineated physiographic regions, basin characteristics, regression equations, error estimates, definitions, and data sources. This study supersedes previous studies of low flows in Virginia.

Methods for estimating flow-duration and annual mean-flow statistics for ungaged streams in Oklahoma

USGS Publications Warehouse

Esralew, Rachel A.; Smith, S. Jerrod

2010-01-01

Flow statistics can be used to provide decision makers with surface-water information needed for activities such as water-supply permitting, flow regulation, and other water rights issues. Flow statistics could be needed at any location along a stream. Most often, streamflow statistics are needed at ungaged sites, where no flow data are available to compute the statistics. Methods are presented in this report for estimating flow-duration and annual mean-flow statistics for ungaged streams in Oklahoma. Flow statistics included the (1) annual (period of record), (2) seasonal (summer-autumn and winter-spring), and (3) 12 monthly duration statistics, including the 20th, 50th, 80th, 90th, and 95th percentile flow exceedances, and the annual mean-flow (mean of daily flows for the period of record). Flow statistics were calculated from daily streamflow information collected from 235 streamflow-gaging stations throughout Oklahoma and areas in adjacent states. A drainage-area ratio method is the preferred method for estimating flow statistics at an ungaged location that is on a stream near a gage. The method generally is reliable only if the drainage-area ratio of the two sites is between 0.5 and 1.5. Regression equations that relate flow statistics to drainage-basin characteristics were developed for the purpose of estimating selected flow-duration and annual mean-flow statistics for ungaged streams that are not near gaging stations on the same stream. Regression equations were developed from flow statistics and drainage-basin characteristics for 113 unregulated gaging stations. Separate regression equations were developed by using U.S. Geological Survey streamflow-gaging stations in regions with similar drainage-basin characteristics. These equations can increase the accuracy of regression equations used for estimating flow-duration and annual mean-flow statistics at ungaged stream locations in Oklahoma. Streamflow-gaging stations were grouped by selected drainage-basin characteristics by using a k-means cluster analysis. Three regions were identified for Oklahoma on the basis of the clustering of gaging stations and a manual delineation of distinguishable hydrologic and geologic boundaries: Region 1 (western Oklahoma excluding the Oklahoma and Texas Panhandles), Region 2 (north- and south-central Oklahoma), and Region 3 (eastern and central Oklahoma). A total of 228 regression equations (225 flow-duration regressions and three annual mean-flow regressions) were developed using ordinary least-squares and left-censored (Tobit) multiple-regression techniques. These equations can be used to estimate 75 flow-duration statistics and annual mean-flow for ungaged streams in the three regions. Drainage-basin characteristics that were statistically significant independent variables in the regression analyses were (1) contributing drainage area; (2) station elevation; (3) mean drainage-basin elevation; (4) channel slope; (5) percentage of forested canopy; (6) mean drainage-basin hillslope; (7) soil permeability; and (8) mean annual, seasonal, and monthly precipitation. The accuracy of flow-duration regression equations generally decreased from high-flow exceedance (low-exceedance probability) to low-flow exceedance (high-exceedance probability) . This decrease may have happened because a greater uncertainty exists for low-flow estimates and low-flow is largely affected by localized geology that was not quantified by the drainage-basin characteristics selected. The standard errors of estimate of regression equations for Region 1 (western Oklahoma) were substantially larger than those standard errors for other regions, especially for low-flow exceedances. These errors may be a result of greater variability in low flow because of increased irrigation activities in this region. Regression equations may not be reliable for sites where the drainage-basin characteristics are outside the range of values of independent vari

LFSTAT - Low-Flow Analysis in R

NASA Astrophysics Data System (ADS)

Koffler, Daniel; Laaha, Gregor

2013-04-01

The calculation of characteristic stream flow during dry conditions is a basic requirement for many problems in hydrology, ecohydrology and water resources management. As opposed to floods, a number of different indices are used to characterise low flows and streamflow droughts. Although these indices and methods of calculation have been well documented in the WMO Manual on Low-flow Estimation and Prediction [1], a comprehensive software was missing which enables a fast and standardized calculation of low flow statistics. We present the new software package lfstat to fill in this obvious gap. Our software package is based on the statistical open source software R, and expands it to analyse daily stream flow data records focusing on low-flows. As command-line based programs are not everyone's preference, we also offer a plug-in for the R-Commander, an easy to use graphical user interface (GUI) provided for R which is based on tcl/tk. The functionality of lfstat includes estimation methods for low-flow indices, extreme value statistics, deficit characteristics, and additional graphical methods to control the computation of complex indices and to illustrate the data. Beside the basic low flow indices, the baseflow index and recession constants can be computed. For extreme value statistics, state-of-the-art methods for L-moment based local and regional frequency analysis (RFA) are available. The tools for deficit characteristics include various pooling and threshold selection methods to support the calculation of drought duration and deficit indices. The most common graphics for low flow analysis are available, and the plots can be modified according to the user preferences. Graphics include hydrographs for different periods, flexible streamflow deficit plots, baseflow visualisation, recession diagnostic, flow duration curves as well as double mass curves, and many more. From a technical point of view, the package uses a S3-class called lfobj (low-flow objects). This objects are usual R-data-frames including date, flow, hydrological year and possibly baseflow information. Once these objects are created, analysis can be performed by mouse-click and a script can be saved to make the analysis easily reproducible. At the moment we are offering implementation of all major methods proposed in the WMO manual on Low-flow Estimation and Predictions [1]. Future plans include a dynamic low flow report in odt-file format using odf-weave which allows automatic updates if data or analysis change. We hope to offer a tool to ease and structure the analysis of stream flow data focusing on low-flows and to make analysis transparent and communicable. The package can also be used in teaching students the first steps in low-flow hydrology. The software packages can be installed from CRAN (latest stable) and R-Forge: http://r-forge.r-project.org (development version). References: [1] Gustard, Alan; Demuth, Siegfried, (eds.) Manual on Low-flow Estimation and Prediction. Geneva, Switzerland, World Meteorological Organization, (Operational Hydrology Report No. 50, WMO-No. 1029).

Continuous Improvement and Employee Engagement, Part 2: Design, Implementation, and Outcomes of a Daily Management System.

PubMed

Maurer, Marsha; Browall, Pamela; Phelan, Cynthia; Sanchez, Sandra; Sulmonte, Kimberlyann; Wandel, Jane; Wang, Allison

2018-04-01

A daily management system (DMS) can be used to implement continuous quality improvement and advance employee engagement. It can empower staff to identify problems in the care environment that impact quality or work flow and to address them on a daily basis. Through a DMS, improvement becomes the work of everyone, every day. The authors of this 2-part series describe their work to develop a DMS. Part 2 describes the implementation and outcomes of the program.

Multiple regression and inverse moments improve the characterization of the spatial scaling behavior of daily streamflows in the Southeast United States

USGS Publications Warehouse

Farmer, William H.; Over, Thomas M.; Vogel, Richard M.

2015-01-01

Understanding the spatial structure of daily streamflow is essential for managing freshwater resources, especially in poorly-gaged regions. Spatial scaling assumptions are common in flood frequency prediction (e.g., index-flood method) and the prediction of continuous streamflow at ungaged sites (e.g. drainage-area ratio), with simple scaling by drainage area being the most common assumption. In this study, scaling analyses of daily streamflow from 173 streamgages in the southeastern US resulted in three important findings. First, the use of only positive integer moment orders, as has been done in most previous studies, captures only the probabilistic and spatial scaling behavior of flows above an exceedance probability near the median; negative moment orders (inverse moments) are needed for lower streamflows. Second, assessing scaling by using drainage area alone is shown to result in a high degree of omitted-variable bias, masking the true spatial scaling behavior. Multiple regression is shown to mitigate this bias, controlling for regional heterogeneity of basin attributes, especially those correlated with drainage area. Previous univariate scaling analyses have neglected the scaling of low-flow events and may have produced biased estimates of the spatial scaling exponent. Third, the multiple regression results show that mean flows scale with an exponent of one, low flows scale with spatial scaling exponents greater than one, and high flows scale with exponents less than one. The relationship between scaling exponents and exceedance probabilities may be a fundamental signature of regional streamflow. This signature may improve our understanding of the physical processes generating streamflow at different exceedance probabilities. 

Comparisons of xylem sap flow and water vapour flux at the stand level and derivation of canopy conductance for Scots pine

NASA Astrophysics Data System (ADS)

Granier, A.; Biron, P.; Köstner, B.; Gay, L. W.; Najjar, G.

1996-03-01

Simultaneous measurements of xylem sap flow and water vapour flux over a Scots pine ( Pinus sylvestris) forest (Hartheim, Germany), were carried out during the Hartheim Experiment (HartX), an intensive observation campaign of the international programme REKLIP. Sap flow was measured every 30 min using both radial constant heating (Granier, 1985) and two types of Cermak sap flowmeters installed on 24 trees selected to cover a wide range of the diameter classes of the stand (min 8 cm; max 17.5 cm). Available energy was high during the observation period (5.5 to 6.9 mm.day-1), and daily cumulated sap flow on a ground area basis varied between 2.0 and 2.7 mm day-1 depending on climate conditions. Maximum hourly values of sap flow reached 0.33 mm h-1, i.e., 230 W m-2. Comparisons of sap flow with water vapour flux as measured with two OPEC (One Propeller Eddy Correlation, University of Arizona) systems showed a time lag between the two methods, sap flow lagging about 90 min behind vapour flux. After taking into account this time lag in the sap flow data set, a good agreement was found between both methods: sap flow = 0.745* vapour flux, r 2 = 0.86. The difference between the two estimates was due to understory transpiration. Canopy conductance ( g c ) was calculated from sap flow measurements using the reverse form of Penman-Monteith equation and climatic data measured 4 m above the canopy. Variations of g c were well correlated ( r 2 = 0.85) with global radiation ( R) and vapour pressure deficit ( vpd). The quantitative expression for g c = f ( R, vpd) was very similar to that previously found with maritime pine ( Pinus pinaster) in the forest of Les Landes, South Western France.

Optimization of contour ridge water harvesting systems for arid zones.

NASA Astrophysics Data System (ADS)

Berliner, Pedro; Arazi, Adit

2017-04-01

Runoff is generated along slopes in semi-arid regions during rainfall events and flows into the lower lying areas, usually ephemeral streams. Depending on the slope and volume of water involved, the flow can become turbulent and cause the detachments of soil particles (erosion). The purpose of the system under investigation is to capture the water after a relatively short flow distance and allow it to be absorbed by the soil. This action accomplishes two objectives: erosion is averted and the stored water can be used for plant production. Depending on the ratio of contributing to receiving areas and storm characteristics the stored water can be significantly higher than the precipitation. The objective of the present project was to develop a simple model that describes the above biomass production in such a system and allows to determine the optimum distribution of structures along a given slope in order to meet one criteria (e.g. minimize variance, maximize production, maximize lowest production, etc.) or a suite of them. The basic assumption is that tree above ground biomass production is linearly related to transpired water, the latter driven by an external force (potential evaporation) and modulated by water availability in the soil. PET is computed using the standard Penman-Monteith formulation for evaporation from open water bodies, if the latter is not available. Four water fluxes are computed: Evaporation, Transpiration, Runoff and Drainage, the first two not interacting directly. All of the above mentioned fluxes and rates are daily lumped values and water content in the profile is updated daily, assuming that rainfall events happen after the computation of fluxes. Daily water inputs are estimated from rainfall data and computed runoff. A dynamic runoff coefficient (=cumulative generated runoff generated/cumulative precipitation) was derived from measurements carried out in the area and used in order to estimate runoff volumes from total recorded precipitation and varying runoff generating areas. Tree development, as parameterized by cross-sectional canopy area, was estimated from the sigmoid that describes cross-sectional as a function of cumulative water used. Results of simulations carried out for consecutive five year periods in one thirty-year period indicated that contour ridges at 2 m. intervals resulted in the highest canopy covered area, irrespective of soil depth.

Dynamics of transpiration, sap flow and use of stored water in tropical forest canopy trees.

Treesearch

Frederick C. Meinzer; Shelley A. James; Guillermo Goldstein

2004-01-01

In large trees the daily onset of transpiration causes water to be withdrawn from internal storage compartments resulting in lags between changes in transpiration and sap flow at the base of the tree. We measured time courses of sap flow, hydraulic resistance, plant water potential and stomatal resistance in co-occuring tropical forest canopy trees with trunk diameters...

Influence of sampling frequency and load calculation methods on quantification of annual river nutrient and suspended solids loads.

PubMed

Elwan, Ahmed; Singh, Ranvir; Patterson, Maree; Roygard, Jon; Horne, Dave; Clothier, Brent; Jones, Geoffrey

2018-01-11

Better management of water quality in streams, rivers and lakes requires precise and accurate estimates of different contaminant loads. We assessed four sampling frequencies (2 days, weekly, fortnightly and monthly) and five load calculation methods (global mean (GM), rating curve (RC), ratio estimator (RE), flow-stratified (FS) and flow-weighted (FW)) to quantify loads of nitrate-nitrogen (NO 3 - -N), soluble inorganic nitrogen (SIN), total nitrogen (TN), dissolved reactive phosphorus (DRP), total phosphorus (TP) and total suspended solids (TSS), in the Manawatu River, New Zealand. The estimated annual river loads were compared to the reference 'true' loads, calculated using daily measurements of flow and water quality from May 2010 to April 2011, to quantify bias (i.e. accuracy) and root mean square error 'RMSE' (i.e. accuracy and precision). The GM method resulted into relatively higher RMSE values and a consistent negative bias (i.e. underestimation) in estimates of annual river loads across all sampling frequencies. The RC method resulted in the lowest RMSE for TN, TP and TSS at monthly sampling frequency. Yet, RC highly overestimated the loads for parameters that showed dilution effect such as NO 3 - -N and SIN. The FW and RE methods gave similar results, and there was no essential improvement in using RE over FW. In general, FW and RE performed better than FS in terms of bias, but FS performed slightly better than FW and RE in terms of RMSE for most of the water quality parameters (DRP, TP, TN and TSS) using a monthly sampling frequency. We found no significant decrease in RMSE values for estimates of NO 3 - N, SIN, TN and DRP loads when the sampling frequency was increased from monthly to fortnightly. The bias and RMSE values in estimates of TP and TSS loads (estimated by FW, RE and FS), however, showed a significant decrease in the case of weekly or 2-day sampling. This suggests potential for a higher sampling frequency during flow peaks for more precise and accurate estimates of annual river loads for TP and TSS, in the study river and other similar conditions.

Impacts of precipitation and temperature trends on different time scales on the water cycle and water resource availability in mountainous Mediterranean catchments.

NASA Astrophysics Data System (ADS)

José Pérez-Palazón, María; Pimentel, Rafael; Herrero, Javier; José Polo, María

2017-04-01

Climatology trends, precipitation and temperature variations condition the hydrological evolution of the river flow response at basin and sub-basin scales. The link between both climate and flow trends is crucial in mountainous areas, where small variations in temperature can produce significant impacts on precipitation (occurrence as rainfall or snowfall), snowmelt and evaporation, and consequently very different flow signatures. This importance is greater in semiarid regions, where the high variability of the climatic annual and seasonal regimes usually amplifies this impact on river flow. The Sierra Nevada National Park (Southern Spain), with altitudes ranging from 2000 to 3500 m.a.s.l., is part of the global climate change observatories network and a clear example of snow regions in a semiarid environment. This mountain range is head of different catchments, being the Guadalfeo River Basin one of the most influenced by the snow regime. This study shows the observed 55-year (1961-2015) trends of annual precipitation and daily mean temperature, and the associated impacts on snowfall and snow persistence, and the resulting trend of the annual river flow in the Guadalfeo River Basin (Southern Spain), a semiarid abrupt mountainous area (up to 3450 m a.s.l.) facing the Mediterranean Sea where the Alpine and Mediterranean climates coexist in a domain highly influenced by the snow regime, and a significant seasonality in the flow regime. The annual precipitation and annual daily mean temperature experimented a decreasing trend of 2.05 mm/year and an increasing trend of 0.037 °C/year, respectively, during the study period, with a high variability on a decadal basis. However, the torrential precipitation events are more frequent in the last few years of the study period, with an apparently increasing associated dispersion. The estimated annual snowfall trend shows a decreasing trend of 0.24 mm/year, associated to the decrease of precipitation rather than to temperature increase. From the analyses of river flow observations and hydrological modelling, these trends result in an estimated decreasing annual trend of the mean river inflow to reservoirs of 0.091 m3/s, which is equivalent to a mean loss of 2.87 hm3/year during the study period. Nonetheless, these results are associated to a high variability of both extreme values and the annual and decadal values. Moreover, the decrease of the annual inflow is approximately a 25% higher than the loss of precipitation, due to the impact on the different water fluxes from the snowpack associated to the enhanced torrential behaviour of both snowfall/rainfall occurrence and snow persistence. The results show the complexity of hydrological processes in Mediterranean regions, especially under the snow influence, and point out to a significant shift in the precipitation and temperature regime, and thus on the snow-affected hydrological variables in the study area, with a decrease of the available water resource volume in the medium and long term. However, on an annual basis, years with an intense snowfall regime but mild and longer dry periods result in a significant increase of the annual river flow and water storage. Reservoir operation criteria and water allocation should undergo a revision based on hydrological modelling of the snow regions and scenario analysis.

Effect of two different bleaching regimens on the gloss of tooth colored restorative materials.

PubMed

Yalcin, Filiz; Gürgan, Sevil

2005-05-01

Vital tooth bleaching with peroxide is one of the most common cosmetic procedures in dentistry and can be accomplished using a variety of methods or regimens. Recently, new generation of tooth color restorative materials were introduced to market. The purpose of this in vitro study was to determine the gloss changes of three different tooth color restorative materials: Flowable composite (Filtek Flow/3M), packable composite (Filtek P60/3M) and ormocer (Definite/DEGUSSA) after two different bleaching regimens (Vivastyle/VIVADENT) and (Crest Professional Whitestrips/PROCTER and GAMBLE). 16 specimens 30 x 30 x 2 mm size were fabricated from each restorative material. After gloss values were measured with gloss meter, at two different angles of illumination (20 and 60 degrees ), 10% carbamide peroxide (Vivastyle) was applied for 2 h per day for fourteen days to the half of the specimens while 6.5% hydrogen peroxide strip bands (Crest Professional Whitestrips) were applied to the remaining eight of the specimens for 30 min twice daily for 14 days. During the test period the specimens were stored in 37 degrees C and 100% relative humidity. At the end of bleaching regimen the gloss measurements were repeated and the data were subjected to statistical analysis. The Wilcoxon Signed Rank Test analysis revealed that the gloss values were affected by both bleaching regimens (P=0.012). Whitestrips decreased the gloss values of Filtek P60 (at 20 and 60 degrees , P<0.001) and Filtek Flow (at 20 degrees , P=0.05 and at 60 degrees , P=0.05) significantly compared to Vivastyle, while the gloss values of Definite did not show any significant change between Vivastyle and Whitestrips application (at 20 degrees P=0.279; at 60 degrees , P=0.279, Mann-Whitney U Test). The gloss values of materials were significantly different before (at 20 degrees P<0.001; at 60 degrees , P=0.003) and after bleaching (at 20 degrees P<0.05; at 60 degrees , P<0.05) with the highest value of Filtek Flow followed Filtek P60 and then by Definite (Kruskal Wallis test). As the gloss of tooth colored restorative materials could be affected by bleaching regimens, it is necessary to consider the type of the material before starting the treatment.

Streamflow Forecasting Using Nuero-Fuzzy Inference System

NASA Astrophysics Data System (ADS)

Nanduri, U. V.; Swain, P. C.

2005-12-01

The prediction of flow into a reservoir is fundamental in water resources planning and management. The need for timely and accurate streamflow forecasting is widely recognized and emphasized by many in water resources fraternity. Real-time forecasts of natural inflows to reservoirs are of particular interest for operation and scheduling. The physical system of the river basin that takes the rainfall as an input and produces the runoff is highly nonlinear, complicated and very difficult to fully comprehend. The system is influenced by large number of factors and variables. The large spatial extent of the systems forces the uncertainty into the hydrologic information. A variety of methods have been proposed for forecasting reservoir inflows including conceptual (physical) and empirical (statistical) models (WMO 1994), but none of them can be considered as unique superior model (Shamseldin 1997). Owing to difficulties of formulating reasonable non-linear watershed models, recent attempts have resorted to Neural Network (NN) approach for complex hydrologic modeling. In recent years the use of soft computing in the field of hydrological forecasting is gaining ground. The relatively new soft computing technique of Adaptive Neuro-Fuzzy Inference System (ANFIS), developed by Jang (1993) is able to take care of the non-linearity, uncertainty, and vagueness embedded in the system. It is a judicious combination of the Neural Networks and fuzzy systems. It can learn and generalize highly nonlinear and uncertain phenomena due to the embedded neural network (NN). NN is efficient in learning and generalization, and the fuzzy system mimics the cognitive capability of human brain. Hence, ANFIS can learn the complicated processes involved in the basin and correlate the precipitation to the corresponding discharge. In the present study, one step ahead forecasts are made for ten-daily flows, which are mostly required for short term operational planning of multipurpose reservoirs. A Neuro-Fuzzy model is developed to forecast ten-daily flows into the Hirakud reservoir on River Mahanadi in the state of Orissa in India. Correlation analysis is carried out to find out the most influential variables on the ten daily flow at Hirakud. Based on this analysis, four variables, namely, flow during the previous time period, ql1, rainfall during the previous two time periods, rl1 and rl2, and flow during the same period in previous year, qpy, are identified as the most influential variables to forecast the ten daily flow. Performance measures such as Root Mean Square Error (RMSE), Correlation Coefficient (CORR) and coefficient of efficiency R2 are computed for training and testing phases of the model to evaluate its performance. The results indicate that the ten-daily forecasting model is efficient in predicting the high and medium flows with reasonable accuracy. The forecast of low flows is associated with less efficiency. REFERENCES Jang, J.S.R. (1993). "ANFIS: Adaptive - network- based fuzzy inference system." IEEE Trans. on Systems, Man and Cybernetics, 23 (3), 665-685. Shamseldin, A.Y. (1997). "Application of a neural network technique to rainfall-runoff modeling." Journal of Hydrology, 199, 272-294. World Meteorological Organization (1975). Intercomparison of conceptual models used in operational hydrological forecasting. World Meteorological Organization, Technical Report No.429, Geneva, Switzerland.

Inferring Aquifer Transmissivity from River Flow Data

NASA Astrophysics Data System (ADS)

Trichakis, Ioannis; Pistocchi, Alberto

2016-04-01

Daily streamflow data is the measurable result of many different hydrological processes within a basin; therefore, it includes information about all these processes. In this work, recession analysis applied to a pan-European dataset of measured streamflow was used to estimate hydrogeological parameters of the aquifers that contribute to the stream flow. Under the assumption that base-flow in times of no precipitation is mainly due to groundwater, we estimated parameters of European shallow aquifers connected with the stream network, and identified on the basis of the 1:1,500,000 scale Hydrogeological map of Europe. To this end, Master recession curves (MRCs) were constructed based on the RECESS model of the USGS for 1601 stream gauge stations across Europe. The process consists of three stages. Firstly, the model analyses the stream flow time-series. Then, it uses regression to calculate the recession index. Finally, it infers characteristics of the aquifer from the recession index. During time-series analysis, the model identifies those segments, where the number of successive recession days is above a certain threshold. The reason for this pre-processing lies in the necessity for an adequate number of points when performing regression at a later stage. The recession index derives from the semi-logarithmic plot of stream flow over time, and the post processing involves the calculation of geometrical parameters of the watershed through a GIS platform. The program scans the full stream flow dataset of all the stations. For each station, it identifies the segments with continuous recession that exceed a predefined number of days. When the algorithm finds all the segments of a certain station, it analyses them and calculates the best linear fit between time and the logarithm of flow. The algorithm repeats this procedure for the full number of segments, thus it calculates many different values of recession index for each station. After the program has found all the recession segments, it performs calculations to determine the expression for the MRC. Further processing of the MRCs can yield estimates of transmissivity or response time representative of the aquifers upstream of the station. These estimates can be useful for large scale (e.g. continental) groundwater modelling. The above procedure allowed calculating values of transmissivity for a large share of European aquifers, ranging from Tmin = 4.13E-04 m²/d to Tmax = 8.12E+03 m²/d, with an average value Taverage = 9.65E+01 m²/d. These results are in line with the literature, indicating that the procedure may provide realistic results for large-scale groundwater modelling. In this contribution we present the results in the perspective of their application for the parameterization of a pan-European bi-dimensional shallow groundwater flow model.

Statistical procedures for evaluating daily and monthly hydrologic model predictions

USGS Publications Warehouse

Coffey, M.E.; Workman, S.R.; Taraba, J.L.; Fogle, A.W.

2004-01-01

The overall study objective was to evaluate the applicability of different qualitative and quantitative methods for comparing daily and monthly SWAT computer model hydrologic streamflow predictions to observed data, and to recommend statistical methods for use in future model evaluations. Statistical methods were tested using daily streamflows and monthly equivalent runoff depths. The statistical techniques included linear regression, Nash-Sutcliffe efficiency, nonparametric tests, t-test, objective functions, autocorrelation, and cross-correlation. None of the methods specifically applied to the non-normal distribution and dependence between data points for the daily predicted and observed data. Of the tested methods, median objective functions, sign test, autocorrelation, and cross-correlation were most applicable for the daily data. The robust coefficient of determination (CD*) and robust modeling efficiency (EF*) objective functions were the preferred methods for daily model results due to the ease of comparing these values with a fixed ideal reference value of one. Predicted and observed monthly totals were more normally distributed, and there was less dependence between individual monthly totals than was observed for the corresponding predicted and observed daily values. More statistical methods were available for comparing SWAT model-predicted and observed monthly totals. The 1995 monthly SWAT model predictions and observed data had a regression Rr2 of 0.70, a Nash-Sutcliffe efficiency of 0.41, and the t-test failed to reject the equal data means hypothesis. The Nash-Sutcliffe coefficient and the R r2 coefficient were the preferred methods for monthly results due to the ability to compare these coefficients to a set ideal value of one.

Acute Inactivity Impairs Glycemic Control but Not Blood Flow to Glucose Ingestion

PubMed Central

Reynolds, Leryn J; Credeur, Daniel P; Holwerda, Seth W; Leidy, Heather J; Fadel, Paul J; Thyfault, John P

2014-01-01

Purpose Insulin-stimulated increases in skeletal muscle blood flow play a role in glucose disposal. Indeed, 7 days of aerobic exercise in type 2 diabetes patients increased blood flow responses to an oral glucose tolerance test (OGTT) and improved glucose tolerance. More recent work suggests that reduced daily physical activity impairs glycemic control (GC) in healthy individuals. Herein, we sought to determine if an acute reduction in daily activity (from >10,000 to <5,000 steps/day) for 5 days (RA5) in healthy individuals reduced insulin-stimulated blood flow and GC in parallel and if a 1 day return to activity (RTA1) improved these outcomes. Methods OGTTs were performed as a stimulus to increase insulin in 14 healthy, recreationally active men (24±1.1 yrs) at baseline, RA5, and RTA1. Measures of insulin sensitivity (Matsuda index) and femoral and brachial artery blood flow were made during the OGTT. Free living measures of GC including peak postprandial glucose (peak PPG) were also made via continuous glucose monitoring. Results Femoral and brachial artery blood flow increased during the OGTT but neither was significantly impacted by changes in physical activity (p>0.05). However, insulin sensitivity was decreased by RA5 (11.3±1.5 to 8.0±1.0; p<0.05). Likewise, free living GC measures of peak post prandial blood glucose (113±3 to 123±5 mg/dL; p<0.05) was significantly increased at RA5. Interestingly, insulin sensitivity and GC as assessed by peak PPG were not restored after RTA1 (p>0.05). Conclusions Thus, acute reductions in physical activity impaired GC and insulin sensitivity; however blood flow responses to an OGTT were not affected. Further, a 1 day return to activity was not sufficient to normalize GC following 5 days of reduced daily physical activity. PMID:25207931

Development of stream-subsurface flow module in sub-daily simulation of Escherichia coli using SWAT

NASA Astrophysics Data System (ADS)

Kim, Minjeong; Boithias, Laurie; Cho, Kyung Hwa; Silvera, Norbert; Thammahacksa, Chanthamousone; Latsachack, Keooudone; Rochelle-Newall, Emma; Sengtaheuanghoung, Oloth; Pierret, Alain; Pachepsky, Yakov A.; Ribolzi, Olivier

2017-04-01

Water contaminated with pathogenic bacteria poses a large threat to public health, especially in the rural areas in the tropics where sanitation and drinking water facilities are often lacking. Several studies have used the Soil and Water Assessment Tool (SWAT) to predict the export of in-stream bacteria at a watershed-scale. However, SWAT is limited to in-stream processes, such as die-off, resuspension and, deposition; and it is usually implemented on a daily time step using the SCS Curve Number method, making it difficult to explore the dynamic fate and transport of bacteria during short but intense events such as flash floods in tropical humid montane headwaters. To address these issues, this study implemented SWAT on an hourly time step using the Green-Ampt infiltration method, and tested the effects of subsurface flow (LATQ+GWQ in SWAT) on bacterial dynamics. We applied the modified SWAT model to the 60-ha Houay Pano catchment in Northern Laos, using sub-daily rainfall and discharge measurements, electric conductivity-derived fractions of overland and subsurface flows, suspended sediments concentrations, and the number of fecal indicator organism Escherichia coli monitored at the catchment outlet from 2011 to 2013. We also took into account land use change by delineating the watershed with the 3-year composite land use map. The results show that low subsurface flow of less than 1 mm recovered the underestimation of E. coli numbers during the dry season, while high subsurface flow caused an overestimation during the wet season. We also found that it is more reasonable to apply the stream-subsurface flow interaction to simulate low in-stream bacteria counts. Using fecal bacteria to identify and understand the possible interactions between overland and subsurface flows may well also provide some insight into the fate of other bacteria, such as those involved in biogeochemical fluxes both in-stream and in the adjacent soils and hyporheic zones.

Low-flow frequency and flow duration of selected South Carolina streams in the Pee Dee River basin through March 2007

USGS Publications Warehouse

Feaster, Toby D.; Guimaraes, Wladmir B.

2009-01-01

Part of the mission of the South Carolina Department of Health and Environmental Control and the South Carolina Department of Natural Resources is to protect and preserve South Carolina's water resources. Doing so requires an ongoing understanding of streamflow characteristics of the rivers and streams in South Carolina. A particular need is information concerning the low-flow characteristics of streams; this information is especially important for effectively managing the State's water resources during critical flow periods such as the severe drought that occurred between 1998 and 2002 and the most recent drought that occurred between 2006 and 2009. In 2008, the U.S. Geological Survey, in cooperation with the South Carolina Department of Health and Environmental Control, initiated a study to update low-flow statistics at continuous-record streamgaging stations operated by the U.S. Geological Survey in South Carolina. Under this agreement, the low-flow characteristics at continuous-record streamgaging stations will be updated in a systematic manner during the monitoring and assessment of the eight major basins in South Carolina as defined and grouped according to the South Carolina Department of Health and Environmental Control's Watershed Water Quality Management Strategy. Depending on the length of record available at the continuous-record streamgaging stations, low-flow frequency characteristics are estimated for annual minimum 1-, 3-, 7-, 14-, 30-, 60-, and 90-day average flows with recurrence intervals of 2, 5, 10, 20, 30, and 50 years. Low-flow statistics are presented for 18 streamgaging stations in the Pee Dee River basin. In addition, daily flow durations for the 5-, 10-, 25-, 50-, 75-, 90-, and 95-percent probability of exceedance also are presented for the stations. The low-flow characteristics were computed from records available through March 31, 2007. The last systematic update of low-flow characteristics in South Carolina occurred more than 20 years ago and included data through March 1987. Of the 17 streamgaging stations included in this study, 15 had low-flow characteristics that were published in previous U.S. Geological Survey reports. A comparison of the low-flow characteristic for the minimum average flow for a 7-consecutive-day period with a 10-year recurrence interval from this study with the most recently published values indicated that 10 of the 15 streamgaging stations had values that were within ±25 percent of each other. Nine of the 15 streamgaging stations had negative percentage differences indicating the low-flow statistic had decreased since the previous study, 4 streamgaging stations had positive percent differences indicating that the low-flow statistic had increased since the previous study, and 2 streamgaging stations had a zero percent difference indicating no change since the previous study. The low-flow characteristics are influenced by length of record, hydrologic regime under which the record was collected, techniques used to do the analysis, and other changes that may have occurred in the watershed.

Estimates of tropical analysis differences in daily values produced by two operational centers

NASA Technical Reports Server (NTRS)

Kasahara, Akira; Mizzi, Arthur P.

1992-01-01

To assess the uncertainty of daily synoptic analyses for the atmospheric state, the intercomparison of three First GARP Global Experiment level IIIb datasets is performed. Daily values of divergence, vorticity, temperature, static stability, vertical motion, mixing ratio, and diagnosed diabatic heating rate are compared for the period of 26 January-11 February 1979. The spatial variance and mean, temporal mean and variance, 2D wavenumber power spectrum, anomaly correlation, and normalized square difference are employed for comparison.

Hydrologic system state at debris flow initiation in the Pitztal catchment, Austria

NASA Astrophysics Data System (ADS)

Mostbauer, Karin; Hrachowitz, Markus; Prenner, David; Kaitna, Roland

2017-04-01

Debris flows represent a severe hazard in mountain regions. Though significant effort has been made to forecast such events, the trigger conditions as well as the hydrologic disposition of a watershed at the time of debris flow occurrence are not well understood. To improve our knowledge on the connection between debris flow initiation and the hydrologic system, this study applies a semi-distributed conceptual rainfall-runoff model, linking different system state variables such as soil moisture, snowmelt, or runoff with documented debris flow events in the Pitztal watershed, western Austria. The hydrologic modelling was performed on a daily basis between 1953 and 2012. High-intensity rainfall could be identified as the dominant trigger (31 out of 43 debris flows), while triggering exclusively by low-intensity, long-lasting rainfall was only observed in one single case. The remaining events were related to snowmelt; whether all of these events where triggered by rain-on-snow, or whether some of these events were actually triggered by snowmelt only, remains unclear since the occurrence of un- resp. underrecorded rainfall was detected frequently. The usage of a conceptual hydrological model for investigating debris flow initiation constitutes a novel approach in debris flow research and was assessed as very valuable. For future studies, it is recommended to evaluate also sub-daily information. As antecedent snowmelt was found to be much more important to debris flow initiation than antecedent rainfall, it might prove beneficial to include snowmelt in the commonly used rainfall intensity-duration thresholds.

Comparison of two methods for estimating discharge and nutrient loads from Tidally affected reaches of the Myakka and Peace Rivers, West-Central Florida

USGS Publications Warehouse

Levesque, V.A.; Hammett, K.M.

1997-01-01

The Myakka and Peace River Basins constitute more than 60 percent of the total inflow area and contribute more than half the total tributary inflow to the Charlotte Harbor estuarine system. Water discharge and nutrient enrichment have been identified as significant concerns in the estuary, and consequently, it is important to accurately estimate the magnitude of discharges and nutrient loads transported by inflows from both rivers. Two methods for estimating discharge and nutrient loads from tidally affected reaches of the Myakka and Peace Rivers were compared. The first method was a tidal-estimation method, in which discharge and nutrient loads were estimated based on stage, water-velocity, discharge, and water-quality data collected near the mouths of the rivers. The second method was a traditional basin-ratio method in which discharge and nutrient loads at the mouths were estimated from discharge and loads measured at upstream stations. Stage and water-velocity data were collected near the river mouths by submersible instruments, deployed in situ, and discharge measurements were made with an acoustic Doppler current profiler. The data collected near the mouths of the Myakka River and Peace River were filtered, using a low-pass filter, to remove daily mixed-tide effects with periods less than about 2 days. The filtered data from near the river mouths were used to calculate daily mean discharge and nutrient loads. These tidal-estimation-method values were then compared to the basin-ratio-method values. Four separate 30-day periods of differing streamflow conditions were chosen for monitoring and comparison. Discharge and nutrient load estimates computed from the tidal-estimation and basin-ratio methods were most similar during high-flow periods. However, during high flow, the values computed from the tidal-estimation method for the Myakka and Peace Rivers were consistently lower than the values computed from the basin-ratio method. There were substantial differences between discharges and nutrient loads computed from the tidal-estimation and basin-ratio methods during low-flow periods. Furthermore, the differences between the methods were not consistent. Discharges and nutrient loads computed from the tidal-estimation method for the Myakka River were higher than those computed from the basin-ratio method, whereas discharges and nutrients loads computed by the tidal-estimation method for the Peace River were not only lower than those computed from the basin-ratio method, but they actually reflected a negative, or upstream, net movement. Short-term tidal measurement results should be used with caution, because antecedent conditions can influence the discharge and nutrient loads. Continuous tidal data collected over a 1- or 2-year period would be necessary to more accurately estimate the tidally affected discharge and nutrient loads for the Myakka and Peace River Basins.

Improvement of emergency department patient flow using lean thinking.

PubMed

Sánchez, Miquel; Suárez, Montse; Asenjo, María; Bragulat, Ernest

2018-05-01

To apply lean thinking in triage acuity level-3 patients in order to improve emergency department (ED) throughtput and waiting time. A prospective interventional study. An ED of a tertiary care hospital. Triage acuity level-3 patients. To apply lean techniques such as value stream mapping, workplace organization, reduction of wastes and standardization by the frontline staff. Two periods were compared: (i) pre-lean: April-September, 2015; and (ii) post-lean: April-September, 2016. Variables included: median process time (time from beginning of nurse preparation to the end of nurse finalization after doctor disposition) of both discharged and transferred to observation patients; median length of stay; median waiting time; left without being seen, 72-h revisit and mortality rates, and daily number of visits. There was no additional staff or bed after lean implementation. Despite an increment in the daily number of visits (+8.3%, P < 0.001), significant reductions in process time of discharged (182 vs 160 min, P < 0.001) and transferred to observation (186 vs 176 min, P < 0.001) patients, in length of stay (389 vs 329 min, P < 0.001), and in waiting time (71 vs 48 min, P < 0.001) were achieved after lean implementation. No significant differences were registered in left without being seen rate (5.23% vs 4.95%), 72-h revisit rate (3.41% vs 3.93%), and mortality rate (0.23% vs 0.15%). Lean thinking is a methodology that can improve triage acuity level-3 patient flow in the ED, resulting in better throughput along with reduced waiting time.

GCLAS: a graphical constituent loading analysis system

USGS Publications Warehouse

McKallip, T.E.; Koltun, G.F.; Gray, J.R.; Glysson, G.D.

2001-01-01

The U. S. Geological Survey has developed a program called GCLAS (Graphical Constituent Loading Analysis System) to aid in the computation of daily constituent loads transported in stream flow. Due to the relative paucity with which most water-quality data are collected, computation of daily constituent loads is moderately to highly dependent on human interpretation of the relation between stream hydraulics and constituent transport. GCLAS provides a visual environment for evaluating the relation between hydraulic and other covariate time series and the constituent chemograph. GCLAS replaces the computer program Sedcalc, which is the most recent USGS sanctioned tool for constructing sediment chemographs and computing suspended-sediment loads. Written in a portable language, GCLAS has an interactive graphical interface that permits easy entry of estimated values and provides new tools to aid in making those estimates. The use of a portable language for program development imparts a degree of computer platform independence that was difficult to obtain in the past, making implementation more straightforward within the USGS' s diverse computing environment. Some of the improvements introduced in GCLAS include (1) the ability to directly handle periods of zero or reverse flow, (2) the ability to analyze and apply coefficient adjustments to concentrations as a function of time, streamflow, or both, (3) the ability to compute discharges of constituents other than suspended sediment, (4) the ability to easily view data related to the chemograph at different levels of detail, and (5) the ability to readily display covariate time series data to provide enhanced visual cues for drawing the constituent chemograph.

Development and integration of sub-hourly rainfall-runoff modeling capability within a watershed model

USDA-ARS?s Scientific Manuscript database

Increasing urbanization changes runoff patterns to be flashy and instantaneous with decreased base flow. A model with the ability to simulate sub-daily rainfall–runoff processes and continuous simulation capability is required to realistically capture the long-term flow and water quality trends in w...

Comparison of corn transpiration, eddy covariance, and soil water loss

USDA-ARS?s Scientific Manuscript database

Stem flow gages are used to estimate plant transpiration, but only a few studies compare transpiration with other measures of soil water loss. The purpose of this study was to compare transpiration from stem flow measurements with soil water changes estimated by daily neutron probe readings. Monitor...

Improving riverine constituent concentration and flux estimation by accounting for antecedent discharge conditions

NASA Astrophysics Data System (ADS)

Zhang, Qian; Ball, William P.

2017-04-01

Regression-based approaches are often employed to estimate riverine constituent concentrations and fluxes based on typically sparse concentration observations. One such approach is the recently developed WRTDS ("Weighted Regressions on Time, Discharge, and Season") method, which has been shown to provide more accurate estimates than prior approaches in a wide range of applications. Centered on WRTDS, this work was aimed at developing improved models for constituent concentration and flux estimation by accounting for antecedent discharge conditions. Twelve modified models were developed and tested, each of which contains one additional flow variable to represent antecedent conditions and which can be directly derived from the daily discharge record. High-resolution (∼daily) data at nine diverse monitoring sites were used to evaluate the relative merits of the models for estimation of six constituents - chloride (Cl), nitrate-plus-nitrite (NOx), total Kjeldahl nitrogen (TKN), total phosphorus (TP), soluble reactive phosphorus (SRP), and suspended sediment (SS). For each site-constituent combination, 30 concentration subsets were generated from the original data through Monte Carlo subsampling and then used to evaluate model performance. For the subsampling, three sampling strategies were adopted: (A) 1 random sample each month (12/year), (B) 12 random monthly samples plus additional 8 random samples per year (20/year), and (C) flow-stratified sampling with 12 regular (non-storm) and 8 storm samples per year (20/year). Results reveal that estimation performance varies with both model choice and sampling strategy. In terms of model choice, the modified models show general improvement over the original model under all three sampling strategies. Major improvements were achieved for NOx by the long-term flow-anomaly model and for Cl by the ADF (average discounted flow) model and the short-term flow-anomaly model. Moderate improvements were achieved for SS, TP, and TKN by the ADF model. By contrast, no such achievement was achieved for SRP by any proposed model. In terms of sampling strategy, performance of all models (including the original) was generally best using strategy C and worst using strategy A, and especially so for SS, TP, and SRP, confirming the value of routinely collecting stormflow samples. Overall, this work provides a comprehensive set of statistical evidence for supporting the incorporation of antecedent discharge conditions into the WRTDS model for estimation of constituent concentration and flux, thereby combining the advantages of two recent developments in water quality modeling.

The FASB explores accounting for future cash flows.

PubMed

Luecke, R W; Meeting, D T

2001-03-01

The FASB's Statement of Financial Accounting Concepts No. 7, Using Cash Flow Information and Present Value in Accounting Measurements (Statement No. 7), presents the board's views regarding how cash-flow information and present values should be used in accounting for future cash flows when information on fair values is not available. Statement No. 7 presents new concepts regarding how an asset's present value should be calculated and when the interest method of allocation should be used. The FASB proposes a present-value method that takes into account the degree of uncertainty associated with future cash flows among different assets and liabilities. The FASB also suggests that rather than use estimated cash flows (in which a single set of cash flows and a single interest rate is used to reflect the risk associated with an asset or liability), accountants should use expected cash flows (in which all expectations about possible cash flows are used) in calculating present values.

Generalized additive regression models of discharge and mean velocity associated with direct-runoff conditions in Texas: Utility of the U.S. Geological Survey discharge measurement database

USGS Publications Warehouse

Asquith, William H.; Herrmann, George R.; Cleveland, Theodore G.

2013-01-01

A database containing more than 17,700 discharge values and ancillary hydraulic properties was assembled from summaries of discharge measurement records for 424 U.S. Geological Survey streamflow-gauging stations (stream gauges) in Texas. Each discharge exceeds the 90th-percentile daily mean streamflow as determined by period-of-record, stream-gauge-specific, flow-duration curves. Each discharge therefore is assumed to represent discharge measurement made during direct-runoff conditions. The hydraulic properties of each discharge measurement included concomitant cross-sectional flow area, water-surface top width, and reported mean velocity. Systematic and statewide investigation of these data in pursuit of regional models for the estimation of discharge and mean velocity has not been previously attempted. Generalized additive regression modeling is used to develop readily implemented procedures by end-users for estimation of discharge and mean velocity from select predictor variables at ungauged stream locations. The discharge model uses predictor variables of cross-sectional flow area, top width, stream location, mean annual precipitation, and a generalized terrain and climate index (OmegaEM) derived for a previous flood-frequency regionalization study. The mean velocity model uses predictor variables of discharge, top width, stream location, mean annual precipitation, and OmegaEM. The discharge model has an adjusted R-squared value of about 0.95 and a residual standard error (RSE) of about 0.22 base-10 logarithm (cubic meters per second); the mean velocity model has an adjusted R-squared value of about 0.67 and an RSE of about 0.063 fifth root (meters per second). Example applications and computations using both regression models are provided. - See more at: http://ascelibrary.org/doi/abs/10.1061/%28ASCE%29HE.1943-5584.0000635#sthash.jhGyPxgZ.dpuf

Effects of particulate air pollution on the respiratory health of subjects who live in three areas in Kanpur, India.

PubMed

Sharma, Mukesh; Kumar, V Narendra; Katiyar, Subodh K; Sharma, Richa; Shukla, Bhanu P; Sengupta, Babu

2004-07-01

In this study, the authors assessed the relationship between daily changes in respiratory health and particulate levels with diameters of (a) less than 10 microm (PM10) and (b) less than 2.5 microm (PM2.5) in Kanpur, India. The subjects (N = 91) were recruited from 3 areas in Kanpur: (1) Indian Institute of Technology (Kanpur), which was a relatively clean area; (b) Vikas Nagar, a typical commercial area; and (c) finally, the residential area of Juhilal Colony. All subjects resided near to air quality monitoring sites. Air quality and peak expiratory flow rate samplings were conducted for 39 d. Once during the sampling period, lung-function tests (i.e., forced expiratory volume in 1 s, forced vital capacity) were performed on each subject. Subjects who resided at the clean site performed at predicted (i.e., acceptable) values more often than did subjects who lived at the remaining 2 sites. Subjects who lived at all 3 sites demonstrated a substantial average deficit in baseline forced vital capacity and forced expiratory volume in 1 s values. The authors used a statistical model to estimate that an increase of 100 microg/m3 of the pollutant PM10 could reduce the mean peak expiratory flow rate of an individual by approximately 3.2 l/min.

Simulation of ground-water flow and rainfall runoff with emphasis on the effects of land cover, Whittlesey Creek, Bayfield County, Wisconsin, 1999-2001

USGS Publications Warehouse

Lenz, Bernard N.; Saad, David A.; Fitzpatrick, Faith A.

2003-01-01

The effects of land cover on flooding and base-flow characteristics of Whittlesey Creek, Bayfield County, Wis., were examined in a study that involved ground-water-flow and rainfall-runoff modeling. Field data were collected during 1999-2001 for synoptic base flow, streambed head and temperature, precipitation, continuous streamflow and stream stage, and other physical characteristics. Well logs provided data for potentiometric-surface altitudes and stratigraphic descriptions. Geologic, soil, hydrography, altitude, and historical land-cover data were compiled into a geographic information system and used in two ground-water-flow models (GFLOW and MODFLOW) and a rainfall-runoff model (SWAT). A deep ground-water system intersects Whittlesey Creek near the confluence with the North Fork, producing a steady base flow of 17?18 cubic feet per second. Upstream from the confluence, the creek has little or no base flow; flow is from surface runoff and a small amount of perched ground water. Most of the base flow to Whittlesey Creek originates as recharge through the permeable sands in the center of the Bayfield Peninsula to the northwest of the surface-water-contributing basin. Based on simulations, model-wide changes in recharge caused a proportional change in simulated base flow for Whittlesey Creek. Changing the simulated amount of recharge by 25 to 50 percent in only the ground-water-contributing area results in relatively small changes in base flow to Whittlesey Creek (about 2?11 percent). Simulated changes in land cover within the Whittlesey Creek surface-water-contributing basin would have minimal effects on base flow and average annual runoff, but flood peaks (based on daily mean flows on peak-flow days) could be affected. Based on the simulations, changing the basin land cover to a reforested condition results in a reduction in flood peaks of about 12 to 14 percent for up to a 100-yr flood. Changing the basin land cover to 25 percent urban land or returning basin land cover to the intensive row-crop agriculture of the 1920s results in flood peaks increasing by as much as 18 percent. The SWAT model is limited to a daily time step, which is adequate for describing the surface-water/ground-water interaction and percentage changes. It may not, however, be adequate in describing peak flow because the instantaneous peak flow in Whittlesey Creek during a flood can be more than twice the magnitude of the daily mean flow during that same flood. In addition, the storage and infiltration capacities of wetlands in the basin are not fully understood and need further study.

Preferential flow pathways revealed by field based stable isotope analysis of CO2 by mid-infrared laser spectroscopy

NASA Astrophysics Data System (ADS)

van Geldern, Robert; Nowak, Martin; Zimmer, Martin; Szizybalski, Alexandra; Myrttinen, Anssi; Barth, Johannes A. C.; Jost, Hj

2016-04-01

A newly developed and commercially available isotope ratio laser spectrometer for CO2 analyses has been tested during a 10-day field monitoring campaign at the Ketzin pilot site for CO2 storage in northern Germany. The laser instrument is based on tunable laser direct absorption in the mid-infrared. The instrument recorded a continuous 10-day carbon stable isotope data set with 30 minutes resolution directly on-site in a field-based laboratory container during a tracer experiment. To test the instruments performance and accuracy the monitoring campaign was accompanied by daily CO2 sampling for laboratory analyses with isotope ratio mass spectrometry (IRMS). The carbon stable isotope ratios measured by conventional IRMS technique and by the new mid-infrared laser spectrometer agree remarkably well within 2σ analytical precision (<0.3 ‰). This proves the capability of the new mid-infrared direct absorption technique to measure high precision and accurate real-time table isotope data directly in the field. The injected CO2 tracer had a distinct δ13C value that was largely different from the reservoir background value. The laser spectroscopy data revealed a prior to this study unknown, intensive dynamic with fast changing δ13C values. The arrival pattern of the tracer suggest that the observed fluctuations were probably caused by migration along separate and distinct preferential flow paths between injection well and observation well. The new technique might contribute to a better tracing of the migration of the underground CO2 plume and help to ensure the long-term integrity of the reservoir.

Use of selenium-silymarin mix reduces lower urinary tract symptoms and prostate specific antigen in men.

PubMed

Vostalova, Jitka; Vidlar, Ales; Ulrichova, Jitka; Vrbkova, Jana; Simanek, Vilim; Student, Vladimir

2013-12-15

The aim of this double-blind, placebo controlled clinical trial was to assess the effects of a combination of selenium and silymarin in men with lower urinary tract symptoms, benign prostatic hyperplasia and a prostate specific antigen (PSA) ≤2.5ng/ml. The volunteers were randomized to two groups: the first one (n=26) received 240μg selenium (in the form of yeast l-selenomethionine) plus 570mg silymarin daily for 6 months and the second (n=29) received placebo. Outcome measures were changes in the International Prostate Symptom Score (IPSS), bladder volume (V), urinary flow rate, ultrasound estimated postvoid residual urine volume (RV), serum PSA, testosterone and selenium levels, safety clinical biochemistry, hematology and oxidative stress parameters at baseline and on day 180. The results showed statistically significant differences (p<0.05) between treatment and control groups for the following parameters: IPSS score, urodynamic parameters: maximal rate of urine flow (Qmax), average flow (Qave), V and RV, total PSA value and serum selenium levels. There was a significant reduction in PSA in the selenium-silymarin group but no effect on blood testosterone level. Overall the treatment was well-tolerated with no adverse effects. Copyright © 2013 Elsevier GmbH. All rights reserved.

Forecasting the Emergency Department Patients Flow.

PubMed

Afilal, Mohamed; Yalaoui, Farouk; Dugardin, Frédéric; Amodeo, Lionel; Laplanche, David; Blua, Philippe

2016-07-01

Emergency department (ED) have become the patient's main point of entrance in modern hospitals causing it frequent overcrowding, thus hospital managers are increasingly paying attention to the ED in order to provide better quality service for patients. One of the key elements for a good management strategy is demand forecasting. In this case, forecasting patients flow, which will help decision makers to optimize human (doctors, nurses…) and material(beds, boxs…) resources allocation. The main interest of this research is forecasting daily attendance at an emergency department. The study was conducted on the Emergency Department of Troyes city hospital center, France, in which we propose a new practical ED patients classification that consolidate the CCMU and GEMSA categories into one category and innovative time-series based models to forecast long and short term daily attendance. The models we developed for this case study shows very good performances (up to 91,24 % for the annual Total flow forecast) and robustness to epidemic periods.

Suspended sediment in the St. Francis River at St. Francis, Arkansas, 1986-95

USGS Publications Warehouse

Green, W. Reed; Barks, C. Shane; Hall, Alan P.

2000-01-01

Daily suspended-sediment concentrations were analyzed from the St. Francis River at St. Francis, Arkansas during 1986 through 1995. Suspended-sediment particle size distribution was measured in selected samples from 1978 through 1998. These data are used to assess changes in suspended-sediment concentrations and loads through time. Suspended-sediment concentrations were positively related to discharge. At higher flows, percent silt-clay was negatively related to discharge. Nonparametric trend analysis (Mann-Kendall test) of suspended-sediment concentration over the period of record indicated a slight decrease in concentration. Flow-adjusted residuals of suspended-sediment concentration also decreased slightly through the same period. No change was identified in annual suspended-sediment load or annual flow-weighted concentration. Continued monitorig of daily-suspended-sediment concentrations at this site and others, and similar data analysis at other sites where data are available will provide a better understanding of sediment transport withint the St. Francis River.

Development of a precipitation-runoff model to simulate unregulated streamflow in the South Fork Flathead River Basin, Montana

USGS Publications Warehouse

Chase, K.J.

2011-01-01

This report documents the development of a precipitation-runoff model for the South Fork Flathead River Basin, Mont. The Precipitation-Runoff Modeling System model, developed in cooperation with the Bureau of Reclamation, can be used to simulate daily mean unregulated streamflow upstream and downstream from Hungry Horse Reservoir for water-resources planning. Two input files are required to run the model. The time-series data file contains daily precipitation data and daily minimum and maximum air-temperature data from climate stations in and near the South Fork Flathead River Basin. The parameter file contains values of parameters that describe the basin topography, the flow network, the distribution of the precipitation and temperature data, and the hydrologic characteristics of the basin soils and vegetation. A primary-parameter file was created for simulating streamflow during the study period (water years 1967-2005). The model was calibrated for water years 1991-2005 using the primary-parameter file. This calibration was further refined using snow-covered area data for water years 2001-05. The model then was tested for water years 1967-90. Calibration targets included mean monthly and daily mean unregulated streamflow upstream from Hungry Horse Reservoir, mean monthly unregulated streamflow downstream from Hungry Horse Reservoir, basin mean monthly solar radiation and potential evapotranspiration, and daily snapshots of basin snow-covered area. Simulated streamflow generally was in better agreement with observed streamflow at the upstream gage than at the downstream gage. Upstream from the reservoir, simulated mean annual streamflow was within 0.0 percent of observed mean annual streamflow for the calibration period and was about 2 percent higher than observed mean annual streamflow for the test period. Simulated mean April-July streamflow upstream from the reservoir was about 1 percent lower than observed streamflow for the calibration period and about 4 percent higher than observed for the test period. Downstream from the reservoir, simulated mean annual streamflow was 17 percent lower than observed streamflow for the calibration period and 12 percent lower than observed streamflow for the test period. Simulated mean April-July streamflow downstream from the reservoir was 13 percent lower than observed streamflow for the calibration period and 6 percent lower than observed streamflow for the test period. Calibrating to solar radiation, potential evapotranspiration, and snow-covered area improved the model representation of evapotranspiration, snow accumulation, and snowmelt processes. Simulated basin mean monthly solar radiation values for both the calibration and test periods were within 9 percent of observed values except during the month of December (28 percent different). Simulated basin potential evapotranspiration values for both the calibration and test periods were within 10 percent of observed values except during the months of January (100 percent different) and February (13 percent different). The larger percent errors in simulated potential evaporation occurred in the winter months when observed potential evapotranspiration values were very small; in January the observed value was 0.000 inches and in February the observed value was 0.009 inches. Simulated start of melting of the snowpack occurred at about the same time as observed start of melting. The simulated snowpack accumulated to 90-100 percent snow-covered area 1 to 3 months earlier than observed snowpack. This overestimated snowpack during the winter corresponded to underestimated streamflow during the same period. In addition to the primary-parameter file, four other parameter files were created: for a "recent" period (1991-2005), a historical period (1967-90), a "wet" period (1989-97), and a "dry" period (1998-2005). For each data file of projected precipitation and air temperature, a single parameter file can be used to simulate a s

Validating alternative methodologies to estimate the regime of temporary rivers when flow data are unavailable.

PubMed

Gallart, F; Llorens, P; Latron, J; Cid, N; Rieradevall, M; Prat, N

2016-09-15

Hydrological data for assessing the regime of temporary rivers are often non-existent or scarce. The scarcity of flow data makes impossible to characterize the hydrological regime of temporary streams and, in consequence, to select the correct periods and methods to determine their ecological status. This is why the TREHS software is being developed, in the framework of the LIFE Trivers project. It will help managers to implement adequately the European Water Framework Directive in this kind of water body. TREHS, using the methodology described in Gallart et al. (2012), defines six transient 'aquatic states', based on hydrological conditions representing different mesohabitats, for a given reach at a particular moment. Because of its qualitative nature, this approach allows using alternative methodologies to assess the regime of temporary rivers when there are no observed flow data. These methods, based on interviews and high-resolution aerial photographs, were tested for estimating the aquatic regime of temporary rivers. All the gauging stations (13) belonging to the Catalan Internal Catchments (NE Spain) with recurrent zero-flow periods were selected to validate this methodology. On the one hand, non-structured interviews were conducted with inhabitants of villages near the gauging stations. On the other hand, the historical series of available orthophotographs were examined. Flow records measured at the gauging stations were used to validate the alternative methods. Flow permanence in the reaches was estimated reasonably by the interviews and adequately by aerial photographs, when compared with the values estimated using daily flows. The degree of seasonality was assessed only roughly by the interviews. The recurrence of disconnected pools was not detected by flow records but was estimated with some divergences by the two methods. The combination of the two alternative methods allows substituting or complementing flow records, to be updated in the future through monitoring by professionals and citizens. Copyright © 2016 Elsevier B.V. All rights reserved.

Modeling suspended sediment transport and assessing the impacts of climate change in a karstic Mediterranean watershed.

PubMed

Nerantzaki, S D; Giannakis, G V; Efstathiou, D; Nikolaidis, N P; Sibetheros, I Α; Karatzas, G P; Zacharias, I

2015-12-15

Mediterranean semi-arid watersheds are characterized by a climate type with long periods of drought and infrequent but high-intensity rainfalls. These factors lead to the formation of temporary flow tributaries which present flashy hydrographs with response times ranging from minutes to hours and high erosion rates with significant sediment transport. Modeling of suspended sediment concentration in such watersheds is of utmost importance due to flash flood phenomena, during which, large quantities of sediments and pollutants are carried downstream. The aim of this study is to develop a modeling framework for suspended sediment transport in a karstic watershed and assess the impact of climate change on flow, soil erosion and sediment transport in a hydrologically complex and intensively managed Mediterranean watershed. The Soil and Water Assessment Tool (SWAT) model was coupled with a karstic flow and suspended sediment model in order to simulate the hydrology and sediment yield of the karstic springs and the whole watershed. Both daily flow data (2005-2014) and monthly sediment concentration data (2011-2014) were used for model calibration. The results showed good agreement between observed and modeled values for both flow and sediment concentration. Flash flood events account for 63-70% of the annual sediment export depending on a wet or dry year. Simulation results for a set of IPCC "A1B" climate change scenarios suggested that major decreases in surface flow (69.6%) and in the flow of the springs (76.5%) take place between the 2010-2049 and 2050-2090 time periods. An assessment of the future ecological flows revealed that the frequency of minimum flow events increases over the years. The trend of surface sediment export during these periods is also decreasing (54.5%) but the difference is not statistically significant due to the variability of the sediment. On the other hand, sediment originating from the springs is not affected significantly by climate change. Copyright © 2015 Elsevier B.V. All rights reserved.

Supporting data for hydrologic studies in San Francisco Bay, California; meteorological measurements at the Port of Redwood City during 1992-1994

USGS Publications Warehouse

Schemel, Laurence E.

1995-01-01

Meteorological data were collected during 1992-94 at the Port of Redwood City, California, to support hydrologic studies in southern San Francisco Bay. The meteorological variables that were measured were air temperature, atmospheric pressure, quantum flux (insolation), and four parameters of wind speed and direction: scalar mean horizontal wind speed, (vector) resultant horizontal wind speed, resultant wind direction, and standard deviation of the wind direction. Hourly mean values based on measurements at five-minute intervals were logged at the site, then transferred to a portable computer monthly. Daily mean values were computed for temperature, insolation, pressure, and scalar wind speed. Hourly- mean and daily-mean values are presented in time- series plots and daily variability and seasonal and annual cycles are described. All data are provided in ASCII files on an IBM-formatted disk. Observations of temperature and wind speed at the Port of Redwood City were compared with measurements made at the San Francisco International Airport. Most daily mean values for temperature agreed within one- to two-tenths of a degree Celsius between the two locations. Daily mean wind speeds at the Port of Redwood City were typically half the values at the San Francisco International Airport. During summers, the differences resulted from stronger wind speeds at the San Francisco International Airport occurring over longer periods of each day. A comparison of hourly wind speeds at the Palo Alto Municipal Airport with those at the Port of Redwood City showed that values were similar in magnitude.

An auxiliary method to reduce potential adverse impacts of projected land developments: subwatershed prioritization.

PubMed

Kalin, Latif; Hantush, Mohamed M

2009-02-01

An index based method is developed that ranks the subwatersheds of a watershed based on their relative impacts on watershed response to anticipated land developments, and then applied to an urbanizing watershed in Eastern Pennsylvania. Simulations with a semi-distributed hydrologic model show that computed low- and high-flow frequencies at the main outlet increase significantly with the projected landscape changes in the watershed. The developed index is utilized to prioritize areas in the urbanizing watershed based on their contributions to alterations in the magnitude of selected flow characteristics at two spatial resolutions. The low-flow measure, 7Q10, rankings are shown to mimic the spatial trend of groundwater recharge rates, whereas average annual maximum daily flow, QAMAX, and average monthly median of daily flows, QMMED, rankings are influenced by both recharge and proximity to watershed outlet. Results indicate that, especially with the higher resolution, areas having quicker responses are not necessarily the more critical areas for high-flow scenarios. Subwatershed rankings are shown to vary slightly with the location of water quality/quantity criteria enforcement. It is also found that rankings of subwatersheds upstream from the site of interest, which could be the main outlet or any interior point in the watershed, may be influenced by the time scale of the hydrologic processes.

River and Reservoir Operations Model, Truckee River basin, California and Nevada, 1998

USGS Publications Warehouse

Berris, Steven N.; Hess, Glen W.; Bohman, Larry R.

2001-01-01

The demand for all uses of water in the Truckee River Basin, California and Nevada, commonly is greater than can be supplied. Storage reservoirs in the system have a maximum effective total capacity equivalent to less than two years of average river flows, so longer-term droughts can result in substantial water-supply shortages for irrigation and municipal users and may stress fish and wildlife ecosystems. Title II of Public Law (P.L.) 101-618, the Truckee?Carson?Pyramid Lake Water Rights Settlement Act of 1990, provides a foundation for negotiating and developing operating criteria, known as the Truckee River Operating Agreement (TROA), to balance interstate and interbasin allocation of water rights among the many interests competing for water from the Truckee River. In addition to TROA, the Truckee River Water Quality Settlement Agreement (WQSA), signed in 1996, provides for acquisition of water rights to resolve water-quality problems during low flows along the Truckee River in Nevada. Efficient execution of many of the planning, management, or environmental assessment requirements of TROA and WQSA will require detailed water-resources data coupled with sound analytical tools. Analytical modeling tools constructed and evaluated with such data could help assess effects of alternative operational scenarios related to reservoir and river operations, water-rights transfers, and changes in irrigation practices. The Truckee?Carson Program of the U.S. Geological Survey, to support U.S. Department of the Interior implementation of P.L. 101-618, is developing a modeling system to support efficient water-resources planning, management, and allocation. The daily operations model documented herein is a part of the modeling system that includes a database management program, a graphical user interface program, and a program with modules that simulate river/reservoir operations and a variety of hydrologic processes. The operations module is capable of simulating lake/ reservoir and river operations including diversion of Truckee River water to the Truckee Canal for transport to the Carson River Basin. In addition to the operations and streamflow-routing modules, the modeling system is structured to allow integration of other modules, such as water-quality and precipitation-runoff modules. The USGS Truckee River Basin operations model was designed to provide simulations that allow comparison of the effects of alternative management practices or allocations on streamflow or reservoir storages in the Truckee River Basin over long periods of time. Because the model was not intended to reproduce historical streamflow or reservoir storage values, a traditional calibration that includes statistical comparisons of observed and simulated values would be problematic with this model and database. This report describes a chronology and background of decrees, agreements, and laws that affect Truckee River operational practices; the construction of the Truckee River daily operations model; the simulation of Truckee River Basin operations, both current and proposed under the draft TROA and WQSA; and suggested model improvements and limitations. The daily operations model uses Hydrological Simulation Program?FORTRAN (HSPF) to simulate flow-routing and reservoir and river operations. The operations model simulates reservoir and river operations that govern streamflow in the Truckee River from Lake Tahoe to Pyramid Lake, including diversions through the Truckee Canal to Lahontan Reservoir in the Carson River Basin. A general overview is provided of daily operations and their simulation. Supplemental information that documents the extremely complex operating rules simulated by the model is available.

Low-flow analysis and selected flow statistics representative of 1930-2002 for streamflow-gaging stations in or near West Virginia

USGS Publications Warehouse

Wiley, Jeffrey B.

2006-01-01

Five time periods between 1930 and 2002 are identified as having distinct patterns of annual minimum daily mean flows (minimum flows). Average minimum flows increased around 1970 at many streamflow-gaging stations in West Virginia. Before 1930, however, there might have been a period of minimum flows greater than any period identified between 1930 and 2002. The effects of climate variability are probably the principal causes of the differences among the five time periods. Comparisons of selected streamflow statistics are made between values computed for the five identified time periods and values computed for the 1930-2002 interval for 15 streamflow-gaging stations. The average difference between statistics computed for the five time periods and the 1930-2002 interval decreases with increasing magnitude of the low-flow statistic. The greatest individual-station absolute difference was 582.5 percent greater for the 7-day 10-year low flow computed for 1970-1979 compared to the value computed for 1930-2002. The hydrologically based low flows indicate approximately equal or smaller absolute differences than biologically based low flows. The average 1-day 3-year biologically based low flow (1B3) and 4-day 3-year biologically based low flow (4B3) are less than the average 1-day 10-year hydrologically based low flow (1Q10) and 7-day 10-year hydrologic-based low flow (7Q10) respectively, and range between 28.5 percent less and 13.6 percent greater. Seasonally, the average difference between low-flow statistics computed for the five time periods and 1930-2002 is not consistent between magnitudes of low-flow statistics, and the greatest difference is for the summer (July 1-September 30) and fall (October 1-December 31) for the same time period as the greatest difference determined in the annual analysis. The greatest average difference between 1B3 and 4B3 compared to 1Q10 and 7Q10, respectively, is in the spring (April 1-June 30), ranging between 11.6 and 102.3 percent greater. Statistics computed for the individual station's record period may not represent the statistics computed for the period 1930 to 2002 because (1) station records are available predominantly after about 1970 when minimum flows were greater than the average between 1930 and 2002 and (2) some short-term station records are mostly during dry periods, whereas others are mostly during wet periods. A criterion-based sampling of the individual station's record periods at stations was taken to reduce the effects of statistics computed for the entire record periods not representing the statistics computed for 1930-2002. The criterion used to sample the entire record periods is based on a comparison between the regional minimum flows and the minimum flows at the stations. Criterion-based sampling of the available record periods was superior to record-extension techniques for this study because more stations were selected and areal distribution of stations was more widespread. Principal component and correlation analyses of the minimum flows at 20 stations in or near West Virginia identify three regions of the State encompassing stations with similar patterns of minimum flows: the Lower Appalachian Plateaus, the Upper Appalachian Plateaus, and the Eastern Panhandle. All record periods of 10 years or greater between 1930 and 2002 where the average of the regional minimum flows are nearly equal to the average for 1930-2002 are determined as representative of 1930-2002. Selected statistics are presented for the longest representative record period that matches the record period for 77 stations in West Virginia and 40 stations near West Virginia. These statistics can be used to develop equations for estimating flow in ungaged stream locations.

Use of a watershed model to characterize the fate and transport of fluometuron, a soil-applied cotton herbicide, in surface water

USGS Publications Warehouse

Coupe, R.H.

2007-01-01

The Soil and Water Assessment Tool (SWAT) was used to characterize the fate and transport of fluometuron (a herbicide used on cotton) in the Bogue Phalia Basin in northwestern Mississippi, USA. SWAT is a basin-scale watershed model, able to simulate hydrological, chemical, and sediment transport processes. After adjustments to a few parameters (specifically the SURLAG variable, the runoff curve number, Manning's N for overland flow, soil available water capacity, and the base-flow alpha factor) the SWAT model fit the observed streamflow well (the Coefficient of Efficiency and R2 were greater than 60). The results from comparing observed fluometuron concentrations with simulated concentrations were reasonable. The simulated concentrations (which were daily averages) followed the pattern of observed concentrations (instantaneous values) closely, but could be off in magnitude at times. Further calibration might have improved the fit, but given the uncertainties in the input data, it was not clear that any improvement would be due to a better understanding of the input variables. ?? 2007 Taylor & Francis.

Snow cover, snowmelt and runoff in the Himalayan River basins

NASA Technical Reports Server (NTRS)

Dey, B.; Sharma, V. K.; Goswami, D. C.; Rao, P. Subba

1988-01-01

Not withstanding the seasonal vagaries of both rainfall amount and snowcover extent, the Himalayan rivers retain their basic perennial character. However, it is the component of snowmelt yield that accounts for some 60 to 70 percent of the total annual flow volumes from Hamilayan watersheds. On this large hydropotential predominantly depends the temporal performance of hydropower generation and major irrigation projects. The large scale effects of Himalayan snowcover on the hydrologic responses of a few selected catchments in western Himalayas was studied. The antecedent effects of snowcover area on long and short term meltwater yields can best be analyzed by developing appropriate hydrologic models forecasting the pattern of snowmelt as a function of variations in snowcover area. It is hoped that these models would be of practical value in the management of water resources. The predictability of meltwater for the entire snowmelt season was studied, as was the concurrent flow variation in adjacent watersheds, and their hydrologic significance. And the applicability of the Snowmelt-Runoff Model for real time forecast of daily discharges during the major part of the snowmelt season is examined.

A new approach to flow simulation using hybrid models

NASA Astrophysics Data System (ADS)

Solgi, Abazar; Zarei, Heidar; Nourani, Vahid; Bahmani, Ramin

2017-11-01

The necessity of flow prediction in rivers, for proper management of water resource, and the need for determining the inflow to the dam reservoir, designing efficient flood warning systems and so forth, have always led water researchers to think about models with high-speed response and low error. In the recent years, the development of Artificial Neural Networks and Wavelet theory and using the combination of models help researchers to estimate the river flow better and better. In this study, daily and monthly scales were used for simulating the flow of Gamasiyab River, Nahavand, Iran. The first simulation was done using two types of ANN and ANFIS models. Then, using wavelet theory and decomposing input signals of the used parameters, sub-signals were obtained and were fed into the ANN and ANFIS to obtain hybrid models of WANN and WANFIS. In this study, in addition to the parameters of precipitation and flow, parameters of temperature and evaporation were used to analyze their effects on the simulation. The results showed that using wavelet transform improved the performance of the models in both monthly and daily scale. However, it had a better effect on the monthly scale and the WANFIS was the best model.

Characteristics of seasonal variation and solar activity dependence of the geomagnetic solar quiet daily variation

NASA Astrophysics Data System (ADS)

Shinbori, A.; Koyama, Y.; Nose, M.; Hori, T.

2017-12-01

Characteristics of seasonal variation and solar activity dependence of the X- and Y-components of the geomagnetic solar quiet (Sq) daily variation at Memanbetsu in mid-latitudes and Guam near the equator have been investigated using long-term geomagnetic field data with 1-h time resolution from 1957 to 2016. In this analysis, we defined the quiet day when the maximum value of the Kp index is less than 3 for that day. In this analysis, we used the monthly average of the adjusted daily F10.7 corresponding to geomagnetically quiet days. For identification of the monthly mean Sq variation in the X and Y components (Sq-X and Sq-Y), we first determined the baseline of the X and Y components from the average value from 22 to 2 h (LT: local time) for each quiet day. Next, we calculated a deviation from the baseline of the X- and Y-components of the geomagnetic field for each quiet day, and computed the monthly mean value of the deviation for each local time. As a result, Sq-X and Sq-Y shows a clear seasonal variation and solar activity dependence. The amplitude of seasonal variation increases significantly during high solar activities, and is proportional to the solar F10.7 index. The pattern of the seasonal variation is quite different between Sq-X and Sq-Y. The result of the correlation analysis between the solar F10.7 index and Sq-X and Sq-Y shows almost the linear relationship, but the slope and intercept of the linear fitted line varies as function of local time and month. This implies that the sensitivity of Sq-X and Sq-Y to the solar activity is different for different local times and seasons. The local time dependence of the offset value of Sq-Y at Guam and its seasonal variation suggest a magnetic field produced by inter-hemispheric field-aligned currents (FACs). From the sign of the offset value of Sq-Y, it is infer that the inter-hemispheric FACs flow from the summer to winter hemispheres in the dawn and dusk sectors and from the winter to summer hemispheres in the pre-noon to afternoon sectors. From the slope of the linear fitted line, we observe a weak solar activity dependence of the inter-hemispheric FACs, which shows that the intensity of inter-hemispheric FACs has positive and negative correlations in the morning-noon and afternoon sectors, respectively.

Characterizing effects of hydropower plants on sub-daily flow regimes

NASA Astrophysics Data System (ADS)

Bejarano, María Dolores; Sordo-Ward, Álvaro; Alonso, Carlos; Nilsson, Christer

2017-07-01

A characterization of short-term changes in river flow is essential for understanding the ecological effects of hydropower plants, which operate by turning the turbines on or off to generate electricity following variations in the market demand (i.e., hydropeaking). The goal of our study was to develop an approach for characterizing the effects of hydropower plant operations on within-day flow regimes across multiple dams and rivers. For this aim we first defined ecologically meaningful metrics that provide a full representation of the flow regime at short time scales from free-flowing rivers and rivers exposed to hydropeaking. We then defined metrics that enable quantification of the deviation of the altered short-term flow regime variables from those of the unaltered state. The approach was successfully tested in two rivers in northern Sweden, one free-flowing and another regulated by cascades of hydropower plants, which were additionally classified based on their impact on short-term flows in sites of similar management. The largest differences between study sites corresponded to metrics describing sub-daily flow magnitudes such as amplitude (i.e., difference between the highest and the lowest hourly flows) and rates (i.e., rise and fall rates of hourly flows). They were closely followed by frequency-related metrics accounting for the numbers of within-day hourly flow patterns (i.e., rises, falls and periods of stability of hourly flows). In comparison, between-site differences for the duration-related metrics were smallest. In general, hydropeaking resulted in higher within-day flow amplitudes and rates and more but shorter periods of a similar hourly flow patterns per day. The impacted flow feature and the characteristics of the impact (i.e., intensity and whether the impact increases or decreases whatever is being described by the metric) varied with season. Our approach is useful for catchment management planning, defining environmental flow targets, prioritizing river restoration or dam reoperation efforts and contributing information for relicensing hydropower dams.

Cultural Orientations, Daily Activities, and Adjustment in Mexican American Youth

ERIC Educational Resources Information Center

McHale, Susan M.; Updegraff, Kimberly A.; Kim, Ji-Yeon; Cansler, Emily

2009-01-01

The links between youth's daily activities and adjustment and the role of cultural practices and values in these links were studied in 469 youth from 237 Mexican American families. In home interviews, data on mothers', fathers', and two adolescent-age siblings' cultural practices (language use, social contacts) and values (for familism, for…

76 FR 3840 - Approval of One-Year Extension for Attaining the 1997 8-Hour Ozone Standard for the Delaware...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-01-21

... 4th highest daily 8-hour monitored ozone value during the 2009 ozone season is 0.084 parts per million... Philadelphia Area's 4th highest daily 8-hour monitored value during the 2009 ozone season is 0.084 ppm or less...

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chambers, Mark S.; Posner, Marshall; Jones, Christopher Uwe

Purpose: To study the efficacy and safety of cevimeline in two double-blind trials (Studies 003 and 004) enrolling patients with head and neck cancer in whom xerostomia developed after radiotherapy. Methods and Materials: Subjects were randomly assigned to receive cevimeline, 30 mg three times daily, or placebo for 12 weeks, with the possibility of dose escalation to 45 mg three times daily at 6 weeks. The primary efficacy endpoint was the patient's final global evaluation of oral dryness; change in unstimulated salivary flow was a secondary endpoint. Results: Five hundred seventy subjects (284 in Study 003 and 286 in Studymore » 004) were randomized. Significantly more cevimeline-treated subjects than placebo recipients (47.4% vs. 33.3%, p = 0.0162) in Study 003 reported improvement in dry mouth in the final global evaluation of oral dryness. No significant difference between groups in the final global evaluation was seen in Study 004, in which a high placebo response rate of 47.6% was observed. In both studies, cevimeline-treated subjects had significantly greater increases in the objective measure of unstimulated salivary flow than placebo recipients (p 0.0093 [Study 003] and p = 0.0215 [Study 004]), whereas no significant differences in stimulated salivary flow were observed. The most frequent adverse event was increased sweating. Conclusion: Cevimeline was well tolerated by patients with xerostomia after radiotherapy for head and neck cancer, and oral administration of 30-45 mg of cevimeline three times daily increased unstimulated salivary flow.« less

Cevimeline for the treatment of postirradiation xerostomia in patients with head and neck cancer.

PubMed

Chambers, Mark S; Posner, Marshall; Jones, Christopher Uwe; Biel, Merrill A; Hodge, Kenneth M; Vitti, Robert; Armstrong, Ingrid; Yen, Cindy; Weber, Randal S

2007-07-15

To study the efficacy and safety of cevimeline in two double-blind trials (Studies 003 and 004) enrolling patients with head and neck cancer in whom xerostomia developed after radiotherapy. Subjects were randomly assigned to receive cevimeline, 30 mg three times daily, or placebo for 12 weeks, with the possibility of dose escalation to 45 mg three times daily at 6 weeks. The primary efficacy endpoint was the patient's final global evaluation of oral dryness; change in unstimulated salivary flow was a secondary endpoint. Five hundred seventy subjects (284 in Study 003 and 286 in Study 004) were randomized. Significantly more cevimeline-treated subjects than placebo recipients (47.4% vs. 33.3%, p = 0.0162) in Study 003 reported improvement in dry mouth in the final global evaluation of oral dryness. No significant difference between groups in the final global evaluation was seen in Study 004, in which a high placebo response rate of 47.6% was observed. In both studies, cevimeline-treated subjects had significantly greater increases in the objective measure of unstimulated salivary flow than placebo recipients (p = 0.0093 [Study 003] and p = 0.0215 [Study 004]), whereas no significant differences in stimulated salivary flow were observed. The most frequent adverse event was increased sweating. Cevimeline was well tolerated by patients with xerostomia after radiotherapy for head and neck cancer, and oral administration of 30-45 mg of cevimeline three times daily increased unstimulated salivary flow.

Water-quality characteristics of urban runoff and estimates of annual loads in the Tampa Bay area, Florida, 1975-80

USGS Publications Warehouse

Lopez, M.A.; Giovannelli, R.F.

1984-01-01

Rainfall, runoff, and water quality data were collected at nine urban watersheds in the Tampa Bay area from 1975 to 1980. Watershed drainage area ranged from 0.34 to 0.45 sq mi. Land use was mixed. Development ranged from a mostly residential watershed with a 19% impervious surface, to a commercial-residential watershed with a 61% impervious surface. Average biochemical oxygen demand concentrations of base flow at two sites and of stormwater runoff at five sites exceeded treated sewage effluent standards. Average coliform concentrations of stormwater runoff at all sites were several orders of magnitude greater than standards for Florida Class III receiving water (for recreation or propagation and management of fish and wildlife). Average concentrations of lead and zinc in stormwater runoff were consistently higher than Class III standards. Stormwater-runoff loads and base-flow concentrations of biochemical oxygen demand, chemical oxygen demand, total nitrogen, total organic nitrogen, total phosphorus, and lead were related to runoff volume, land use, urban development, and antecedent daily rainfall by multiple linear regression. Stormwater-runoff volume was related to pervious area, hydraulically connected impervious surfaces, storm rainfall, and soil-infiltration index. Base-flow daily discharge was related to drainage area and antecedent daily rainfall. The flow regression equations of this report were used to compute 1979 water-year loads of biochemical oxygen demand, chemical oxygen demand, total nitrogen, total organic nitrogen, total phosphorus , and total lead for the nine Tampa Bay area urban watersheds. (Lantz-PTT)

Long-term changes (1980-2003) in total ozone time series over Northern Hemisphere midlatitudes

NASA Astrophysics Data System (ADS)

Białek, Małgorzata

2006-03-01

Long-term changes in total ozone time series for Arosa, Belsk, Boulder and Sapporo stations are examined. For each station we analyze time series of the following statistical characteristics of the distribution of daily ozone data: seasonal mean, standard deviation, maximum and minimum of total daily ozone values for all seasons. The iterative statistical model is proposed to estimate trends and long-term changes in the statistical distribution of the daily total ozone data. The trends are calculated for the period 1980-2003. We observe lessening of negative trends in the seasonal means as compared to those calculated by WMO for 1980-2000. We discuss a possibility of a change of the distribution shape of ozone daily data using the Kolmogorov-Smirnov test and comparing trend values in the seasonal mean, standard deviation, maximum and minimum time series for the selected stations and seasons. The distribution shift toward lower values without a change in the distribution shape is suggested with the following exceptions: the spreading of the distribution toward lower values for Belsk during winter and no decisive result for Sapporo and Boulder in summer.

A computer program for simulating salinity loads in streams

USGS Publications Warehouse

Glover, Kent C.

1978-01-01

A FORTRAN IV program that simulates salinity loads in streams is described. Daily values of stream-discharge in cubic feet per second, or stream-discharge and specific conductance in micromhos, are used to estimate daily loads in tons by one of five available methods. The loads are then summarized by computing either total and mean monthly loads or various statistics for each calendar day. Results are output in tabular and, if requested, punch card format. Under selection of appropriate methods for estimating and summarizing daily loads is provided through the coding of program control cards. The program is designed to interface directly with data retrieved from the U.S. Geological Survey WATSTORE Daily Values File. (Woodard-USGS)

Determination of streamflow of the Arkansas River near Bentley in south-central Kansas

USGS Publications Warehouse

Perry, Charles A.

2012-01-01

The Kansas Department of Agriculture, Division of Water Resources, requires that the streamflow of the Arkansas River just upstream from Bentley in south-central Kansas be measured or calculated before groundwater can be pumped from the well field. When the daily streamflow of the Arkansas River near Bentley is less than 165 cubic feet per second (ft3/s), pumping must be curtailed. Daily streamflow near Bentley was calculated by determining the relations between streamflow data from two reference streamgages with a concurrent record of 24 years, one located 17.2 miles (mi) upstream and one located 10.9 mi downstream, and streamflow at a temporary gage located just upstream from Bentley (Arkansas River near Bentley, Kansas). Flow-duration curves for the two reference streamgages indicate that during 1988?2011, the mean daily streamflow was less than 165 ft3/s 30 to 35 percent of the time. During extreme low-flow (drought) conditions, the reach of the Arkansas River between Hutchinson and Maize can lose flow to the adjacent alluvial aquifer, with streamflow losses as much as 1.6 cubic feet per second per mile. Three models were developed to calculate the streamflow of the Arkansas River near Bentley, Kansas. The model chosen depends on the data available and on whether the reach of the Arkansas River between Hutchinson and Maize is gaining or losing groundwater from or to the adjacent alluvial aquifer. The first model was a pair of equations developed from linear regressions of the relation between daily streamflow data from the Bentley streamgage and daily streamflow data from either the Arkansas River near Hutchinson, Kansas, station (station number 07143330) or the Arkansas River near Maize, Kansas, station (station number 07143375). The standard error of the Hutchinson-only equation was 22.8 ft3/s, and the standard error of the Maize-only equation was 22.3 ft3/s. The single-station model would be used if only one streamgage was available. In the second model, the flow gradient between the streamflow near Hutchinson and the streamflow near Maize was used to calculate the streamflow at the Bentley streamgage. This equation resulted in a standard error of 26.7 ft3/s. In the third model, a multiple regression analysis between both the daily streamflow of the Arkansas River near Hutchinson, Kansas, and the daily streamflow of the Arkansas River near Maize, Kansas, was used to calculate the streamflow at the Bentley streamgage. The multiple regression equation had a standard error of 21.2 ft3/s, which was the smallest of the standard errors for all the models. An analysis of the number of low-flow days and the number of days when the reach between Hutchinson and Maize loses flow to the adjacent alluvial aquifer indicates that the long-term trend is toward fewer days of losing conditions. This trend may indicate a long-term increase in water levels in the alluvial aquifer, which could be caused by one or more of several conditions, including an increase in rainfall, a decrease in pumping, a decrease in temperature, and an increase in streamflow upstream from the Hutchinson-to-Maize reach of the Arkansas River.

A similarity based approach to identify homogeneous regions for seasonal forecasting

NASA Astrophysics Data System (ADS)

Schick, Simon; Rössler, Ole; Weingartner, Rolf

2015-04-01

Seasonal runoff forecasting using statistical models is challenged by a large number of candidate predictors and a general weak predictor-predictand relationship. As the area of the target basin increases, often also the available data sets do, thus reinforcing the predictor selection challenge. We propose an approach which follows the idea of 'divide and conquer' as developed in computational sciences and machine learning: First, the macroscale target basin is partitioned into homogeneous regions using all its gauged mesoscale subbasins. Second, one representative subbasin per homogeneous region is identified, for which models are fitted and applied. Third, the resulting forecasts are combined at the scale of the macroscale target basin. This approach requires a suitable method to identify homogeneous regions and representative subbasins. We suggest a way based on hydrological similarity, as catchment similarity estimated with respect to physiographic-climatic descriptors does not necessarily imply similar runoff response. Each descriptor is derived from daily runoff series and aimed to reflect a specific catchment characteristic: autocorrelation coefficient, parameters of fitted Gamma distribution and low/high flow indices (based on daily runoff values) fluctuation of the standard deviation within the yearly cycle (based on weekly runoff values) dominant harmonics obtained from the discrete Fourier transform (based on monthly runoff values) long term trend (based on yearly runoff values) Where necessary, the runoff series first need to be standardized, aggregated, detrended or deseasonalized. As a preliminary study we present the results of a cluster analysis for the Swiss Rhine River as macroscale target basin, which leads to about 40 mesoscale subbasins with runoff series for the period 1991-2010. Problems we have to address include the choice of a clustering algorithm, the identification of an appropriate number of regions and the selection of representative subbasins per region. The results are finally discussed with respect to the runoff regimes as defined in the Hydrological Atlas of Switzerland.

The Stratigraphic Incompleteness of Submarine Channels

NASA Astrophysics Data System (ADS)

Vendettuoli, D.; Clare, M. A.; Hughes Clarke, J. E.; Cartigny, M.; Vellinga, A. J.; Talling, P.; Hizzett, J. L.; Hage, S.; Waltham, D.; Hubbard, S. M.

2017-12-01

Turbidity currents transport prodigious quantities of sediment across the world's oceans through submarine channels. These flows damage strategically important seafloor infrastructure and their deposits host major oil and gas reservoirs. We therefore need to understand these flows, but their very powerful nature makes direct monitoring challenging. Most studies to date focus on the deposits that turbidity currents leave behind in the sedimentological record. However, deposits of individual flows are likely to be reworked by successive flows, but it is unclear as to what extent. How complete is the stratigraphy of these deposits? What percentage of flow deposits are preserved in the rock record? Are some events better preserved than others, and if so, why? We address these questions by re-analysing the most detailed time-lapse mapping yet of a turbidity current system. This field dataset comes from the fjord-head Squamish Delta in British Columbia, Canada where Hughes Clarke (2016) collected 93 near-daily repeat surveys in 2011. These surveys revealed the seafloor response to more than 100 turbidity currents. Here we use temporal changes in seabed elevation to understand patterns of deposition and erosion. We calculate the total thickness of sediment deposited at each location, and document the percentage of sediment that is preserved (i.e. stratigraphic completeness) at multiple time-steps over the surveyed period. The average stratigraphic completeness across the delta near submarine channels is <1%, but this is highly spatially variable. Some levees record up to 40% completeness. The low value is largely due to upstream migrating bedforms that constantly rework previously emplaced sediments. Surprisingly, even at the terminal lobes, stratigraphic completeness is typically <5%. These results provide new insights into the evolution of submarine channels and why their deposits produce a highly incomplete record of submarine flows.

Variable Trends in High Peak Flow Generation Across the Swedish Sub-Arctic

NASA Astrophysics Data System (ADS)

Matti, B.; Dahlke, H. E.; Lyon, S. W.

2015-12-01

There is growing concern about increased frequency and severity of floods and droughts globally in recent years. Improving knowledge on the complexity of hydrological systems and their interactions with climate is essential to be able to determine drivers of these extreme events and to predict changes in these drivers under altered climate conditions. This is particularly true in cold regions such as the Swedish Sub-Arctic where independent shifts in both precipitation and temperature can have significant influence on extremes. This study explores changes in the magnitude and timing of the annual maximum daily flows in 18 Swedish sub-arctic catchments. The Mann-Kendall trend test was used to estimate changes in selected hydrological signatures. Further, a flood frequency analysis was conducted by fitting a Gumbel (Extreme Value type I) distribution whereby selected flood percentiles were tested for stationarity using a generalized least squares regression approach. Our results showed that hydrological systems in cold climates have complex, heterogeneous interactions with climate. Shifts from a snowmelt-dominated to a rainfall-dominated flow regime were evident with all significant trends pointing towards (1) lower flood magnitudes in the spring flood; (2) earlier flood occurrence; (3) earlier snowmelt onset; and (4) decreasing mean summer flows. Decreasing trends in flood magnitude and mean summer flows suggest permafrost thawing and are in agreement with the increasing trends in annual minimum flows. Trends in the selected flood percentiles showed an increase in extreme events over the entire period of record, while trends were variable under shorter periods. A thorough uncertainty analysis emphasized that the applied trend test is highly sensitive to the period of record considered. As such, no clear overall regional pattern could be determined suggesting that how catchments are responding to changes in climatic drivers is strongly influenced by their physical characteristics.

Analysis of stochastic characteristics of the Benue River flow process

NASA Astrophysics Data System (ADS)

Otache, Martins Y.; Bakir, Mohammad; Li, Zhijia

2008-05-01

Stochastic characteristics of the Benue River streamflow process are examined under conditions of data austerity. The streamflow process is investigated for trend, non-stationarity and seasonality for a time period of 26 years. Results of trend analyses with Mann-Kendall test show that there is no trend in the annual mean discharges. Monthly flow series examined with seasonal Kendall test indicate the presence of positive change in the trend for some months, especially the months of August, January, and February. For the stationarity test, daily and monthly flow series appear to be stationary whereas at 1%, 5%, and 10% significant levels, the stationarity alternative hypothesis is rejected for the annual flow series. Though monthly flow appears to be stationary going by this test, because of high seasonality, it could be said to exhibit periodic stationarity based on the seasonality analysis. The following conclusions are drawn: (1) There is seasonality in both the mean and variance with unimodal distribution. (2) Days with high mean also have high variance. (3) Skewness coefficients for the months within the dry season period are greater than those of the wet season period, and seasonal autocorrelations for streamflow during dry season are generally larger than those of the wet season. Precisely, they are significantly different for most of the months. (4) The autocorrelation functions estimated “over time” are greater in the absolute value for data that have not been deseasonalised but were initially normalised by logarithmic transformation only, while autocorrelation functions for i = 1, 2, ..., 365 estimated “over realisations” have their coefficients significantly different from other coefficients.

Development of Inspection and Investigation Techniques to Prepare Debris Flow in Urban Areas

NASA Astrophysics Data System (ADS)

Seong, Joo-Hyun; Jung, Min-Hyeong; Park, Kyung-Han; An, Jai-Wook; Kim, Jiseong

2017-04-01

Due to the urban development, various facilities are located in mountainous areas near the city, and the damage to the occurrence of the debris flow is increasing in the urban area. However, quantitative inspection and investigation techniques are not sufficient for preparing debris flow in the urban area around the world. Therefore, in this study, we developed the debris flow inspection and investigation techniques, which are suitable for urban characteristics, regarding the soil hazard prevention and restoration in urban area. First, the inspection and investigation system is divided into the daily occurrence and the occurrence of the soil hazard event, and the inspection / investigation flow chart were developed based on the kind of inspection and correspondence required for each situation. The types of inspections applied in this study were determined as daily inspection, regular inspections, special emergency inspection, damage emergency inspection and In-depth safety inspection. The management agency, term of inspection, objects to be inspected, and contents of inspection work were presented according to type of each inspection. The daily inspection routinely checks for signs of collapse and conditions of facilities in urban areas which show vulnerability for soil hazard and that are conducted from the management agency. In the case of regular inspection, an expert for soil hazards regularly conducts detailed visual surveys on mountainous areas, steep slopes, prevention facilities and adjacent facilities in vulnerable areas. On the other hand, it was decided that the emergency inspection is carried out in the event of the occurrence of vulnerable element or soil hazards. Acknowledgement This study was conducted with the research iund support by the constructiontechnology research project of the Ministry of Land, Infrastructure and Transport (project number 16SCIP-B069989-04)

Combined effects of projected sea level rise, storm surge, and peak river flows on water levels in the Skagit Floodplain

USGS Publications Warehouse

Hamman, Josheph J; Hamlet, Alan F.; Fuller, Roger; Grossman, Eric E.

2016-01-01

Current understanding of the combined effects of sea level rise (SLR), storm surge, and changes in river flooding on near-coastal environments is very limited. This project uses a suite of numerical models to examine the combined effects of projected future climate change on flooding in the Skagit floodplain and estuary. Statistically and dynamically downscaled global climate model scenarios from the ECHAM-5 GCM were used as the climate forcings. Unregulated daily river flows were simulated using the VIC hydrology model, and regulated river flows were simulated using the SkagitSim reservoir operations model. Daily tidal anomalies (TA) were calculated using a regression approach based on ENSO and atmospheric pressure forcing simulated by the WRF regional climate model. A 2-D hydrodynamic model was used to estimate water surface elevations in the Skagit floodplain using resampled hourly hydrographs keyed to regulated daily flood flows produced by the reservoir simulation model, and tide predictions adjusted for SLR and TA. Combining peak annual TA with projected sea level rise, the historical (1970–1999) 100-yr peak high water level is exceeded essentially every year by the 2050s. The combination of projected sea level rise and larger floods by the 2080s yields both increased flood inundation area (+ 74%), and increased average water depth (+ 25 cm) in the Skagit floodplain during a 100-year flood. Adding sea level rise to the historical FEMA 100-year flood resulted in a 35% increase in inundation area by the 2040's, compared to a 57% increase when both SLR and projected changes in river flow were combined.

Daily river flow prediction based on Two-Phase Constructive Fuzzy Systems Modeling: A case of hydrological - meteorological measurements asymmetry

NASA Astrophysics Data System (ADS)

Bou-Fakhreddine, Bassam; Mougharbel, Imad; Faye, Alain; Abou Chakra, Sara; Pollet, Yann

2018-03-01

Accurate daily river flow forecast is essential in many applications of water resources such as hydropower operation, agricultural planning and flood control. This paper presents a forecasting approach to deal with a newly addressed situation where hydrological data exist for a period longer than that of meteorological data (measurements asymmetry). In fact, one of the potential solutions to resolve measurements asymmetry issue is data re-sampling. It is a matter of either considering only the hydrological data or the balanced part of the hydro-meteorological data set during the forecasting process. However, the main disadvantage is that we may lose potentially relevant information from the left-out data. In this research, the key output is a Two-Phase Constructive Fuzzy inference hybrid model that is implemented over the non re-sampled data. The introduced modeling approach must be capable of exploiting the available data efficiently with higher prediction efficiency relative to Constructive Fuzzy model trained over re-sampled data set. The study was applied to Litani River in the Bekaa Valley - Lebanon by using 4 years of rainfall and 24 years of river flow daily measurements. A Constructive Fuzzy System Model (C-FSM) and a Two-Phase Constructive Fuzzy System Model (TPC-FSM) are trained. Upon validating, the second model has shown a primarily competitive performance and accuracy with the ability to preserve a higher day-to-day variability for 1, 3 and 6 days ahead. In fact, for the longest lead period, the C-FSM and TPC-FSM were able of explaining respectively 84.6% and 86.5% of the actual river flow variation. Overall, the results indicate that TPC-FSM model has provided a better tool to capture extreme flows in the process of streamflow prediction.

Flood Seasonality in a Changing Climate - A Comparison Between Northern Europe and Northeastern North America

NASA Astrophysics Data System (ADS)

Matti, B.; Dahlke, H. E.; Dieppois, B.; Lawler, D.; Lyon, S. W.

2016-12-01

Fluvial flood events have a large impact on humans, both socially and economically. Concurrent with climate change flood seasonality in cold environments is expected to shift from a snowmelt-dominated to a rainfall-dominated flow regime. This would have profound impacts on water management strategies, i.e. flood risk mitigation, drinking water supply and hydro power. In addition, cold climate hydrological systems exhibit complex interactions with catchment properties and large-scale climate fluctuations making the manifestation of changes difficult to detect and predict. Understanding a possible change in flood seasonality is essential to mitigate risk and to keep management strategies viable under a changing climate. This study explored changes in flood seasonality across near-natural catchments in cold environments of the North Atlantic region (40 - 70° N) using circular statistics and trend tests. Results indicate strong seasonality in flooding for snowmelt-dominated catchments with a single peak occurring in spring (March through May), whereas flood peaks are more equally distributed throughout the year for catchments located close to the Atlantic coast and in the south of the study area. Flood seasonality has changed over the past century seen as decreasing trends in summer maximum daily flows and increasing winter and spring maximum daily flows. Mean daily flows corroborate those findings with approximately 50% of the catchments showing significant changes. Comparing Scandinavia to North America the same trends could be detected with a stronger signal at the west coast of Scandinavia due to the Westerlies. Contrasting trends were detected for spring flows, for which North American catchments showed decreasing trends whereas increasing trends were observed across Scandinavia. Such changes in flood seasonality have clear implications for management strategies such as the estimation of design floods for flood prevention measures.

Daily River Flow Forecasting with Hybrid Support Vector Machine – Particle Swarm Optimization

NASA Astrophysics Data System (ADS)

Zaini, N.; Malek, M. A.; Yusoff, M.; Mardi, N. H.; Norhisham, S.

2018-04-01

The application of artificial intelligence techniques for river flow forecasting can further improve the management of water resources and flood prevention. This study concerns the development of support vector machine (SVM) based model and its hybridization with particle swarm optimization (PSO) to forecast short term daily river flow at Upper Bertam Catchment located in Cameron Highland, Malaysia. Ten years duration of historical rainfall, antecedent river flow data and various meteorology parameters data from 2003 to 2012 are used in this study. Four SVM based models are proposed which are SVM1, SVM2, SVM-PSO1 and SVM-PSO2 to forecast 1 to 7 day ahead of river flow. SVM1 and SVM-PSO1 are the models with historical rainfall and antecedent river flow as its input, while SVM2 and SVM-PSO2 are the models with historical rainfall, antecedent river flow data and additional meteorological parameters as input. The performances of the proposed model are measured in term of RMSE and R2 . It is found that, SVM2 outperformed SVM1 and SVM-PSO2 outperformed SVM-PSO1 which meant the additional meteorology parameters used as input to the proposed models significantly affect the model performances. Hybrid models SVM-PSO1 and SVM-PSO2 yield higher performances as compared to SVM1 and SVM2. It is found that hybrid models are more effective in forecasting river flow at 1 to 7 day ahead at the study area.

Water use, ground-water recharge and availability, and quality of water in the Greenwich area, Fairfield County, Connecticut and Westchester County, New York, 2000-2002

USGS Publications Warehouse

Mullaney, John R.

2004-01-01

Ground-water budgets were developed for 32 small basin-based zones in the Greenwich area of southwestern Connecticut, where crystalline-bedrock aquifers supply private wells, to determine the status of residential ground-water consumption relative to rates of ground-water recharge and discharge. Estimated residential ground-water withdrawals for small basins (averaging 1.7 square miles (mi2)) ranged from 0 to 0.16 million gallons per day per square mile (Mgal/d/mi2). To develop these budgets, residential ground-water withdrawals were estimated using multiple-linear regression models that relate water use from public water supply to data on residential property characteristics. Average daily water use of households with public water supply ranged from 219 to 1,082 gallons per day (gal/d). A steady-state finite-difference ground-water- flow model was developed to track water budgets, and to estimate optimal values for hydraulic conductivity of the bedrock (0.05 feet per day) and recharge to the overlying till deposits (6.9 inches) using nonlinear regression. Estimated recharge rates to the small basins ranged from 3.6 to 7.5 inches per year (in/yr) and relate to the percentage of the basin underlain by coarse- grained glacial stratified deposits. Recharge was not applied to impervious areas to account for the effects of urbanization. Net residential ground-water consumption was estimated as ground-water withdrawals increased during the growing season, and ranged from 0 to 0.9 in/yr. Long-term average stream base flows simulated by the ground-water-flow model were compared to calculated values of average base flow and low flow to determine if base flow was substantially reduced in any of the basins studied. Three of the 32 basins studied had simulated base flows less than 3 in/yr, as a result of either ground-water withdrawals or reduced recharge due to urbanization. A water-availability criteria of the difference between the 30-day 2-year low flow and the recharge rate for each basin was explored as a method to rate the status of water consumption in each basin. Water consumption ranged from 0 to 14.3 percent of available water based on this criteria for the 32 basins studied. Base-flow water quality was related to the amount of urbanized area in each basin sampled. Concentrations of total nitrogen and phosphorus, chloride, indicator bacteria, and the number of pesticide detections increased with basin urbanization, which ranged from 18 to 63 percent of basin area.

Low-flow characteristics of the Mississippi River upstream from the Twin Cities Metropolitan Area, Minnesota, 1932-2007

USGS Publications Warehouse

Kessler, Erich; Lorenz, David L.

2010-01-01

The U.S. Geological Survey, in cooperation with the Metropolitan Council, conducted a study to characterize regional low flows during 1932?2007 in the Mississippi River upstream from the Twin Cities metropolitan area in Minnesota and to describe the low-flow profile of the Mississippi River between the confluence of the Crow River and St. Anthony Falls. Probabilities of extremely low flow were estimated for the streamflow-gaging station (Mississippi River near Anoka) and the coincidence of low-flow periods, defined as the extended periods (at least 7 days) when all the daily flows were less than the 10th percentile of daily mean flows for the entire period of record, at four selected streamflow-gaging stations located upstream. The likelihood of extremely low flows was estimated by a superposition method for the Mississippi River near Anoka that created 5,776 synthetic hydrographs resulting in a minimum synthetic low flow of 398 cubic feet per second at a probability of occurrence of 0.0002 per year. Low-flow conditions at the Mississippi River above Anoka were associated with low-flow conditions at two or fewer of four upstream streamflow-gaging stations 42 percent of the time, indicating that sufficient water is available within the basin for many low flows and the occurrence of extremely low-flows is small. However, summer low-flow conditions at the Mississippi River above Anoka were almost always associated with low-stage elevations in three or more of the six upper basin reservoirs. A low-flow profile of the Mississippi River between the confluence of the Crow River and St. Anthony Falls was completed using a real-time kinematic global positioning system, and the water-surface profile was mapped during October 8?9, 2008, and annotated with local landmarks. This was done so that water-use planners could relate free-board elevations of selected water utility structures to the lowest flow conditions during 2008.

Correlations between the circadian patterns of body temperature, metabolism and breathing in rats.

PubMed

Mortola, Jacopo P

2007-02-15

It had been demonstrated previously that the circadian patterns of activity and state of arousal are not essential for the manifestation of the daily patterns of pulmonary ventilation (V(E)), tidal volume (V(T)) and breathing frequency (f). In this study we investigated the extent of the linkage between the circadian pattern of breathing and those of body temperature (T(b)) and metabolic rate (oxygen consumption, V(O2), and carbon dioxide production, V(CO2)). Rats were instrumented for measurements of T(b) (by telemetry), and placed in a chamber for continuous 13-day period of measurement of breathing (by a modification of the barometric methodology), and of V(O2) and V(CO2) (by an open flow method). After the first 4 days in control conditions under a 12 h light:12 h dark (L:D) cycle, a perturbation was introduced on day 4, with an L-phase prolongation of 12 h, and on day 9, with an D-phase prolongation of 12 h. During the control days 1-4, all variables had daily oscillations (higher values in D), in phase with each other. During the perturbations (days 4-13), changes in T(b), V(O2) and V(CO2), averaged over the whole period, correlated significantly better with f than with V(T). Day-by-day X-Y loops indicated that V (E), V(T) and f could lead significantly the changes of T(b), V(O2) and V(CO2), and that these relations changed throughout the perturbation period. In addition, f and V(T) did not change necessarily in phase with each other. It is concluded that neither the oscillation in T(b) nor that in metabolism can be considered the direct cause of the daily oscillation of breathing. Presumably, the circadian pattern of breathing reflects the interplay of the daily patterns of many variables, none acting as the primary guide of the breathing daily rhythm.

Empirical solution of Green-Ampt equation using soil conservation service - curve number values

NASA Astrophysics Data System (ADS)

Grimaldi, S.; Petroselli, A.; Romano, N.

2012-09-01

The Soil Conservation Service - Curve Number (SCS-CN) method is a popular widely used rainfall-runoff model for quantifying the total stream-flow volume generated by storm rainfall, but its application is not appropriate for sub-daily resolutions. In order to overcome this drawback, the Green-Ampt (GA) infiltration equation is considered and an empirical solution is proposed and evaluated. The procedure, named CN4GA (Curve Number for Green-Ampt), aims to calibrate the Green-Ampt model parameters distributing in time the global information provided by the SCS-CN method. The proposed procedure is evaluated by analysing observed rainfall-runoff events; results show that CN4GA seems to provide better agreement with the observed hydrographs respect to the classic SCS-CN method.

Periodic water- and air-temperature records for Utah streams, 1966-70

USGS Publications Warehouse

Whitaker, G.L.

1971-01-01

Since 1967, all Geological Survey hydrographers have been instructed to observe and record the water and air temperatures at times when water-discharge measurements were being made at stream-gaging stations in Utah. The frequency of these observations generally varies from I to 5 weeks, depending upon the magnitude of the stream flow.This report summarizes the periodic water and air temperatures that have been recorded in Utah since that effort began. This information may be of value to individuals or agencies concerned with thermal pollution of streams, or with enforcement of water-quality standards.A compilation of all daily water-temperature records recorded for streams in Utah by the U. S. Geological Survey during the period 1944-68 is contained in Utah Basic-Data Release No. 19.

CREST v2.1 Refined by a Distributed Linear Reservoir Routing Scheme

NASA Astrophysics Data System (ADS)

Shen, X.; Hong, Y.; Zhang, K.; Hao, Z.; Wang, D.

2014-12-01

Hydrologic modeling is important in water resources management, and flooding disaster warning and management. Routing scheme is among the most important components of a hydrologic model. In this study, we replace the lumped LRR (linear reservoir routing) scheme used in previous versions of the distributed hydrological model, CREST (coupled routing and excess storage) by a newly proposed distributed LRR method, which is theoretically more suitable for distributed hydrological models. Consequently, we have effectively solved the problems of: 1) low values of channel flow in daily simulation, 2) discontinuous flow value along the river network during flood events and 3) irrational model parameters. The CREST model equipped with both the routing schemes have been tested in the Gan River basin. The distributed LRR scheme has been confirmed to outperform the lumped counterpart by two comparisons, hydrograph validation and visual speculation of the continuity of stream flow along the river: 1) The CREST v2.1 (version 2.1) with the implementation of the distributed LRR achieved excellent result of [NSCE(Nash coefficient), CC (correlation coefficient), bias] =[0.897, 0.947 -1.57%] while the original CREST v2.0 produced only negative NSCE, close to zero CC and large bias. 2) CREST v2.1 produced more naturally smooth river flow pattern along the river network while v2.0 simulated bumping and discontinuous discharge along the mainstream. Moreover, we further observe that by using the distributed LRR method, 1) all model parameters fell within their reasonable region after an automatic optimization; 2) CREST forced by satellite-based precipitation and PET products produces a reasonably well result, i.e., (NSCE, CC, bias) = (0.756, 0.871, -0.669%) in the case study, although there is still room to improve regarding their low spatial resolution and underestimation of the heavy rainfall events in the satellite products.

Unifying Access to National Hydrologic Data Repositories via Web Services

NASA Astrophysics Data System (ADS)

Valentine, D. W.; Jennings, B.; Zaslavsky, I.; Maidment, D. R.

2006-12-01

The CUAHSI hydrologic information system (HIS) is designed to be a live, multiscale web portal system for accessing, querying, visualizing, and publishing distributed hydrologic observation data and models for any location or region in the United States. The HIS design follows the principles of open service oriented architecture, i.e. system components are represented as web services with well defined standard service APIs. WaterOneFlow web services are the main component of the design. The currently available services have been completely re-written compared to the previous version, and provide programmatic access to USGS NWIS. (steam flow, groundwater and water quality repositories), DAYMET daily observations, NASA MODIS, and Unidata NAM streams, with several additional web service wrappers being added (EPA STORET, NCDC and others.). Different repositories of hydrologic data use different vocabularies, and support different types of query access. Resolving semantic and structural heterogeneities across different hydrologic observation archives and distilling a generic set of service signatures is one of the main scalability challenges in this project, and a requirement in our web service design. To accomplish the uniformity of the web services API, data repositories are modeled following the CUAHSI Observation Data Model. The web service responses are document-based, and use an XML schema to express the semantics in a standard format. Access to station metadata is provided via web service methods, GetSites, GetSiteInfo and GetVariableInfo. The methdods form the foundation of CUAHSI HIS discovery interface and may execute over locally-stored metadata or request the information from remote repositories directly. Observation values are retrieved via a generic GetValues method which is executed against national data repositories. The service is implemented in ASP.Net, and other providers are implementing WaterOneFlow services in java. Reference implementation of WaterOneFlow web services is available. More information about the ongoing development of CUAHSI HIS is available from http://www.cuahsi.org/his/.

Establishment of Textbook Information Management System Based on Active Server Page

ERIC Educational Resources Information Center

Geng, Lihua

2011-01-01

In the process of textbook management of universities, the flow of storage, collection and check of textbook is quite complicated and daily management flow and system also seriously constrains the efficiency of the management process. Thus, in order to combine the information management model and the traditional management model, it is necessary…

Atmospheric blocking as a traffic jam in the jet stream

NASA Astrophysics Data System (ADS)

Nakamura, N.; Huang, S. Y.

2017-12-01

It is demonstrated using the ERA-Interim product that synoptic to intraseasonal variabilities of extratropical circulation in the boreal storm track regions are strongly affected by the zonal convergence of the column-integrated eastward flux of local wave activity (LWA). In particular, from the multi-year daily samples of LWA fluxes, we find that the wintertime zonal LWA flux in the jet exit regions tends to maximize for an intermediate value of column-averaged LWA. This is because an increasing LWA decelerates the zonal flow, eventually weakening the eastward advection of LWA. From theory we argue that large wave events on the decreasing side of the flux curve with increasing LWA cannot be maintained as a stable steady state. Consistent with this argument, observed states corresponding to that side of flux curve often exhibit local wave breaking and blocking events. A close parallelism exists for the traffic flow problem, in which the traffic flux (traffic density times traffic speed) is often observed to maximize for an intermediate value of traffic density. This is because the traffic speed is controlled not only by the imposed speed limit but also by the traffic density — an increasingly heavy traffic slows down the flow naturally and eventually decreases the flux. Once the flux starts to decrease with an increasing traffic density, a traffic jam kicks in suddenly (Lighthill and Whitham 1955, Richards 1956). The above idea is demonstrated by a simple conceptual model based on the equivalent barotropic PV contour design (Nakamura and Huang 2017, JAS), which predicts a threshold of blocking onset. The idea also suggests that the LWA that gives the `flux capacity,' i.e., the maximum LWA flux at a given location, is a useful predictor of local wave breaking/block formation.

An A-train climatology of extratropical cyclone clouds and precipitation

NASA Astrophysics Data System (ADS)

Naud, C. M.; Booth, J.; Del Genio, A. D.; van den Heever, S. C.; Posselt, D. J.

2016-12-01

It is demonstrated using the ERA-Interim product that synoptic to intraseasonal variabilities of extratropical circulation in the boreal storm track regions are strongly affected by the zonal convergence of the column-integrated eastward flux of local wave activity (LWA). In particular, from the multi-year daily samples of LWA fluxes, we find that the wintertime zonal LWA flux in the jet exit regions tends to maximize for an intermediate value of column-averaged LWA. This is because an increasing LWA decelerates the zonal flow, eventually weakening the eastward advection of LWA. From theory we argue that large wave events on the decreasing side of the flux curve with increasing LWA cannot be maintained as a stable steady state. Consistent with this argument, observed states corresponding to that side of flux curve often exhibit local wave breaking and blocking events. A close parallelism exists for the traffic flow problem, in which the traffic flux (traffic density times traffic speed) is often observed to maximize for an intermediate value of traffic density. This is because the traffic speed is controlled not only by the imposed speed limit but also by the traffic density — an increasingly heavy traffic slows down the flow naturally and eventually decreases the flux. Once the flux starts to decrease with an increasing traffic density, a traffic jam kicks in suddenly (Lighthill and Whitham 1955, Richards 1956). The above idea is demonstrated by a simple conceptual model based on the equivalent barotropic PV contour design (Nakamura and Huang 2017, JAS), which predicts a threshold of blocking onset. The idea also suggests that the LWA that gives the `flux capacity,' i.e., the maximum LWA flux at a given location, is a useful predictor of local wave breaking/block formation.

Mitral annular plane systolic excursion/left ventricular length (MAPSE/L) as a simple index for assessing left ventricular longitudinal function in children.

PubMed

Terada, Tomomasa; Mori, Kazuhiro; Inoue, Miki; Yasunobu, Hayabuchi

2016-11-01

Assessment of longitudinal left ventricular (LV) function is important for early detection of cardiac dysfunction. Although mitral annular plane systolic excursion (MAPSE) obtained by M-mode echocardiography offers a simple method for assessing longitudinal LV function, normal values of MAPSE for children change according to body size. To minimize the effects of body size, MAPSE was divided by LV long-axis length (MAPSE/L). MAPSE/L was measured in 210 healthy children from birth to 15 years of age and classified into five subgroups. MAPSE/L was then compared with 10 parameters in 136 children (age, heart rate, mean blood pressure, ejection fraction of the LV (EF), peak atrial flow velocity/peak early diastolic flow velocity of mitral flow, tissue Doppler velocity during systole (s') and early diastole (e'), E/e' ratio, Tei index, and global longitudinal strain (GLS) of the LV by the speckle tracking method). MAPSE/L was significantly lower in the neonate group than in the remaining four groups. MAPSE/L then increased with age to peak at 1-5 years and gradually decreased thereafter. In all cases beyond the neonatal period, MAPSE/L was more than 0.17. Among various parameters, GLS, age, EF, Tei index and s' were significantly associated with MAPSE/L in that order. In univariate analysis, GLS was most significantly associated with MAPSE/L (r=.56). We have established normal reference values for MPSE/L in healthy children. MAPSE/L is expected to offer a simple parameter to evaluate LV longitudinal systolic function during daily routine echocardiography in children. © 2016, Wiley Periodicals, Inc.

Momentary Associations Between Reported Craving and Valuing Health in Daily Smokers.

PubMed

MacLean, Robert Ross; Martino, Steve; Carroll, Kathleen M; Smyth, Joshua M; Pincus, Aaron L; Wilson, Stephen J

2017-06-01

Research suggests that a blunted response to nondrug rewards, especially under conditions associated with strong cigarette cravings, is associated with reduced abstinence motivation in daily smokers. One limitation of previous studies is that they have largely focused on monetary rewards as broad representative of nondrug rewards. It remains unclear whether craving dampens responses to more abstract nondrug rewards, such as personal values. Personal values often have a positive valence and are frequently assumed to remain stable across time and situations. However, there may be time-varying and contextual influences on smokers' appraisal of values in daily life. Characterizing fluctuations in value importance in relation to relapse precipitants (eg, craving) may inform interventions that leverage personal values as motivation for cessation. Daily smokers (n = 18) completed ecological momentary assessment surveys measuring the importance of specific personal values and smoking-related variables during 8 days of monetarily reinforced cigarette abstinence. We hypothesized that value ratings would demonstrate adequate within-person heterogeneity for multilevel modeling and that within-person fluctuations in craving would be negatively related to valuing personal health. All values demonstrated adequate within-person variability for multilevel modeling. Within-person craving was negatively related to health valuation (p = .012) and a cross-level interaction (p > .0001) suggested this effect is stronger for individuals who report greater overall craving. Greater craving is associated with decreased importance of personal health in the moment, particularly for those with high average levels of craving. Timely interventions that bolster importance of health during moments of elevated craving can potentially improve cessation outcomes. This study builds on research highlighting the positive influence of personal values in motivating behavior change. Values are an often used, but poorly studied, construct that has considerable utility in smoking cessation. Valuing personal health is frequently reported as a primary motivator for a quit attempt. Inasmuch as personal health is a distal nondrug reward used to motivate smoking abstinence, naturalistic evaluation of health importance, and motivators for continued smoking (ie, craving) could inform the timing and content of smoking treatment. This study is among the first to evaluate momentary assessment of personal values and craving within daily life. Published by Oxford University Press on behalf of the Society for Research on Nicotine and Tobacco 2017. This work is written by (a) US Government employee(s) and is in the public domain in the US.

Estimating sediment discharge: Appendix D

USGS Publications Warehouse

Gray, John R.; Simões, Francisco J. M.

2008-01-01

Sediment-discharge measurements usually are available on a discrete or periodic basis. However, estimates of sediment transport often are needed for unmeasured periods, such as when daily or annual sediment-discharge values are sought, or when estimates of transport rates for unmeasured or hypothetical flows are required. Selected methods for estimating suspended-sediment, bed-load, bed- material-load, and total-load discharges have been presented in some detail elsewhere in this volume. The purposes of this contribution are to present some limitations and potential pitfalls associated with obtaining and using the requisite data and equations to estimate sediment discharges and to provide guidance for selecting appropriate estimating equations. Records of sediment discharge are derived from data collected with sufficient frequency to obtain reliable estimates for the computational interval and period. Most sediment- discharge records are computed at daily or annual intervals based on periodically collected data, although some partial records represent discrete or seasonal intervals such as those for flood periods. The method used to calculate sediment- discharge records is dependent on the types and frequency of available data. Records for suspended-sediment discharge computed by methods described by Porterfield (1972) are most prevalent, in part because measurement protocols and computational techniques are well established and because suspended sediment composes the bulk of sediment dis- charges for many rivers. Discharge records for bed load, total load, or in some cases bed-material load plus wash load are less common. Reliable estimation of sediment discharges presupposes that the data on which the estimates are based are comparable and reliable. Unfortunately, data describing a selected characteristic of sediment were not necessarily derived—collected, processed, analyzed, or interpreted—in a consistent manner. For example, bed-load data collected with different types of bed-load samplers may not be comparable (Gray et al. 1991; Childers 1999; Edwards and Glysson 1999). The total suspended solids (TSS) analytical method tends to produce concentration data from open-channel flows that are biased low with respect to their paired suspended-sediment concentration values, particularly when sand-size material composes more than about a quarter of the material in suspension. Instantaneous sediment-discharge values based on TSS data may differ from the more reliable product of suspended- sediment concentration values and the same water-discharge data by an order of magnitude (Gray et al. 2000; Bent et al. 2001; Glysson et al. 2000; 2001). An assessment of data comparability and reliability is an important first step in the estimation of sediment discharges. There are two approaches to obtaining values describing sediment loads in streams. One is based on direct measurement of the quantities of interest, and the other on relations developed between hydraulic parameters and sediment- transport potential. In the next sections, the most common techniques for both approaches are briefly addressed.

Determination of flow losses in the Cape Fear River between B. Everett Jordan Lake and Lillington, North Carolina, 2008-2010

USGS Publications Warehouse

Weaver, J. Curtis; McSwain, Kristen Bukowski

2013-01-01

During 2008-2010, the U.S. Geological Survey conducted a hydrologic investigation in cooperation with the Triangle J Council of Governments Cape Fear River Flow Study Committee and the North Carolina Division of Water Resources to collect hydrologic data in the Cape Fear River between B. Everett Jordan Lake and Lillington in central North Carolina to help determine if suspected flow losses occur in the reach. Flow loss analyses were completed by summing the daily flow releases at Jordan Lake Dam with the daily discharges at Deep River at Moncure and Buckhorn Creek near Corinth, then subtracting these values from the daily discharges at Cape Fear River at Lillington. Examination of long-term records revealed that during 10,227 days of the 1983-2010 water years, 408 days (4.0 percent) had flow loss when conditions were relatively steady with respect to the previous day's records. The flow loss that occurred on these 40 days ranged from 0.49 to 2,150 cubic feet per second with a median flow loss of 37.2 cubic feet per second. The months with the highest number of days with flow losses were June (16. percent), September (16.9 percent), and October (19.4 percent). A series of synoptic discharge measurements made on six separate days in 2009 provided "snapshots" of overall flow conditions along the study reach. The largest water diversion is just downstream from the confluence of the Haw and Deep Rivers, and discharges substantially decrease in the main stem downstream from the intake point. Downstream from Buckhorn Dam, minimal gain or loss between the dam and Raven Rock State Park was noted. Analyses of discharge measurements and ratings for two streamgages-one at Deep River at Moncure and the other at Cape Fear River at Lillington-were completed to address the accuracy of the relation between stage and discharge at these sites. The ratings analyses did not indicate a particular time during the 1982-2011 water years in which a consistent bias occurred in the computations of discharge records that would indicate false flow losses. A total of 34 measured discharges at a streamgage on the Haw River below B. Everett Jordan Lake near Moncure were compared with the reported hourly flow releases from Jordan Lake Dam. Because 28 of 34 measurements were within plus or minus 10 percent of the hourly flow releases reported by the U.S Army Corps of Engineers, use of the current discharge computation tables for reporting Jordan Lake Dam flow releases is generally supported. A stage gage was operated on the Cape Fear River at Buckhorn Dam near Corinth to collect continuous stage-only records. Throughout the study period, flow over the dam was observed along its length, and flow loss within the study reach is not attributed to river-level fluctuations at the dam. Water-use information and (or) data were obtained for five industrial facilities, a regional power utility, two municipalities, one small hydropower facility on the Deep River, and one quarry operation also adjacent to the Deep River. The largest water users are the regional power producer, a small hydropower operation, and the two municipalities. The total water-use diversions for these facilities range from almost 25.5 to 38.5 cubic feet per second (39.5 to 59.5 million gallons per day) during the winter and summer periods, respectively. This range is equivalent to 69 to 104 percent of the 37 cubic feet per second median flow loss. The Lockville hydropower station is on the Deep River about 1 mile downstream from the streamgage near Moncure. Run-of-river operations at the facility do not appear to affect flow losses in the study reach. The largest water user in the study area is a regional power producer at a coal-fired power-generation plant located immediately adjacent to the Cape Fear River just downstream from the confluence of the Haw an Deep Rivers. Comparisons of daily water withdrawals, sup-plied by the regional power producer, and discharge records at a streamgage on the diversion canal indicated many days when consumption exceeded the producer's estimates for the cooling towers. Uncertainty surrounding reasonable estimates of consumption remained in effect at the end of the study. Data concerning evaporative losses were compiled using two approaches-an analysis of available pan-evaporation data from a National Weather Service cooperative observer station in Chapel Hill, North Carolina; and a compilation of reference open-water evaporation computed by the State Climate Office of North Carolina. The potential flow loss by evaporation from the main stem and the Deep River was estimated to be in the range of 4 to 14 cubic feet per second during May through October, equivalent to 10 to 38 percent of the 37 cubic feet per second median flow loss. Daily water-use diversions and evaporation losses were compared to flow-loss occurrences during the period April 2008 through September 2010. In comparing the surface-water, water-use, and evaporation data compiled for 2008-2010, it is evident that documented water diversions combined with flow losses by open-water evaporation can exceed the net flow gain in the study area and result in flow losses from the reach. Analysis of data from a streamgage downstream from the regional power plant on the diversion canal adjacent to the Cape Fear River provided insight into the occurrence of an apparent flow loss at the streamgage at Lillington. Assessment of the daily discharges and subsequent hydrographs for the canal streamgage indicated at least 24 instances during the study when the flows suddenly changed by magnitudes of 100 to more that 200 cubic feet per second, resulting in a noted time-lag effect on the downstream discharges at the Lillington streamgage, beginning 8 to 16 hours after the sudden flow change. A fiber-optic distributed temperature-sensing survey was conducted on the Cape Fear River at the Raven Rock State Park reach August 12-14, 2009, to determine if the presence of diabase dikes were preferentially directing groundwater discharge. No temperature anomalies of colder water were measured during the survey, which indicated that at the time of the survey that particular reach of the Cape Fear River was a "no-flow" or losing stream. An aerial thermal-infrared survey was conducted on the Haw and Cape Fear Rivers on February 27, 2010, from Jordan Lake Dam to Lillington to qualitatively delineate areas of groundwater discharge on the basis of the contrast between warm groundwater discharge and cold surface-water temperatures. Dis-charge generally was noted as diffuse seepage, but in a few cases springs were detected as inflow at a discrete point of discharge. Two reaches of the Cape Fear River (regional power plant and Bradley Road reaches) were selected for groundwater monitoring with a transect of piezometers installed within the flood plain. Groundwater-level altitudes at these reaches were analyzed for 1 water year (October 1, 2009, to September 30, 2010). Data collected as part of this study represent only a brief period of time and may not represent all conditions and all years; however, the data indicate that, during the dry summer months, the Cape Fear River within the study area is losing an undetermined quantity of water through seepage. Analyses completed during this investigation indicate a study reach with complex flow patterns affected by numerous concurrent factors resulting in flow losses. The causes of flow loss could not be solely attributed to any one factor. Among the factors considered, the occurrences of water diversions and evaporative losses were determined to be sufficient on some days (particularly during the base-flow period) to exceed the net gain in flows between the upstream and downstream ends of the study area. Losses by diversions and evaporation can exceed the median flow loss of 3 cubic feet per second, which indicates that flow loss from the study reach is real. Groundwater data collected during 2009-2010 indicate the possibility of localized flow loss during the summer, particularly in the impounded reach above Buckhorn Dam. However, no indication of unusual patterns was noted that would cause substantial flow loss by groundwater and surface-water interaction at the river bottom.

Summary of hydrologic data collected during 1976 in Dade County, Florida

USGS Publications Warehouse

Hull, John E.

1978-01-01

During 1976 rainfall was 1.58 inches below the long-term average. Ground-water levels ranged from 0.4 foot above to 0.5 foot below average. The highest and lowest ground water for the year were both 1 foot below their long-term averages. In the Hialeah-Miami Springs area, water levels in wells near the centers of the heaviest pumping ranged from 8.0 to 9.5 feet below msl (mean sea level, 1929); and in the southwest well-field area, ground-water levels near the centers of pumping ranged from 2.0 feet above to 3.0 feet below msl. The combined average daily discharge from nine major streams and canals that flow eastward into tidal waters was 1,666 cubic feet per second (cfs), 609 cfs above the combined average daily flow for the 1975 water year. The combined average daily flow through the Tamiami Canal outlets was 783 cfs, 215 cfs above that of the 1975 water year. The 1976 position of the salt fron in the coastal part of the Biscayne aquifer was about the same as in 1975 except in the vicinity of Mowry Canal south of Homestead Air Force Base where the salt front had encroached farther inland. (Woodard-USGS)

Summary of hydrologic data collected during 1977 in Dade County, Florida

USGS Publications Warehouse

Hull, John E.

1979-01-01

During 1977 rainfall was 1.52 inches above the long-term average in Dade County, Fla. Ground-water levels ranged from 0.3 foot above to 0.1 foot below average. The highest and lowest ground-water levels for the year were 1 foot below and 1 foot above their long-term average. In the Hialeah-Miami Springs area , water levels in wells near the centers of the heaviest pumping ranged from 7.2 to 11.9 feet below mean sea level, 1929; and in the Southwest well-field area, ground-water levels near the centers of pumping ranged from 1.0 foot above to 1.5 feet below mean sea level. In 1977 the combined average daily discharge from nine major streams and canals that flow eastward into tidal waters was 1,712 cubic feet per second (cfs), 46 cfs above the combined average daily flow for 1976. The combined average daily flow through the Tamiami Canal outlets was 582 cfs, 201 cfs above that of 1976. The 1977 position of the salt front in the coastal part of the Biscayne aquifer was about the same as in 1976, except south of Homestead Air Force Base where the salt front had encroached farther inland. (Woodard-USGS)

Summary of hydrologic data collected during 1975 in Dade County, Florida

USGS Publications Warehouse

Hull, John E.; Beaven, T.R.

1977-01-01

During the 1975 calendar year rainfall in Dade County, Fla., was 14.89 inches below the long-term average (57.17 in.). Ground-water levels ranged from 0.1 foot above to 1.1 feet below average. The highest and lowest ground-water levels for the year were both 1 foot below their long-term averages. In the Hialeah-Miami Springs area, ground-water levels in wells near the centers of the heaviest pumping ranged from 9.8 to 11.2 feet below mean sea level and in the Southwest well field area, ground-water levels near the centers of pumping ranged from 3.5 feet above to 3.4 feet below mean sea level. The combined average daily discharge from eight major streams and canals that flow into Biscayne Bay was 1,014 cubic feet per second (cfs), 124 cfs above the combined average daily flow for the 1974 water year. The combined average daily flow through the Tamiami Canal outlets was 568 cfs, 202 cfs below that of the 1974 water year. The position of the salt front in 1975 in the coastal part of the Biscayne aquifer was about the same as in 1974 except at Miami International Airport and Homestead Air Force Base where the salt front had encroached farther inland. (Woodard-USGS)

An analysis of potential water availability from the Charles Mill, Clendening, Piedmont, Pleasant Hill, Senecaville, and Wills Creek Lakes in the Muskingum River Watershed, Ohio

USGS Publications Warehouse

Koltun, G.F.

2014-01-01

This report presents the results of a study to assess potential water availability from the Charles Mill, Clendening, Piedmont, Pleasant Hill, Senecaville, and Wills Creek Lakes, located within the Muskingum River Watershed, Ohio. The assessment was based on the criterion that water withdrawals should not appreciably affect maintenance of recreation-season pool levels in current use. To facilitate and simplify the assessment, it was assumed that historical lake operations were successful in maintaining seasonal pool levels, and that any discharges from lakes constituted either water that was discharged to prevent exceeding seasonal pool levels or discharges intended to meet minimum in-stream flow targets downstream from the lakes. It further was assumed that the volume of water discharged in excess of the minimum in-stream flow target is available for use without negatively impacting seasonal pool levels or downstream water uses and that all or part of it is subject to withdrawal. Historical daily outflow data for the lakes were used to determine the quantity of water that potentially could be withdrawn and the resulting quantity of water that would flow downstream (referred to as “flow-by”) on a daily basis as a function of all combinations of three hypothetical target minimum flow-by amounts (1, 2, and 3 times current minimum in-stream flow targets) and three pumping capacities (1, 2, and 3 million gallons per day). Using both U.S. Geological Survey streamgage data (where available) and lake-outflow data provided by the U.S. Army Corps of Engineers resulted in analytical periods ranging from 51 calendar years for Charles Mill, Clendening, and Piedmont Lakes to 74 calendar years for Pleasant Hill, Senecaville, and Wills Creek Lakes. The observed outflow time series and the computed time series of daily flow-by amounts and potential withdrawals were analyzed to compute and report order statistics (95th, 75th, 50th, 25th, 10th, and 5th percentiles) and means for the analytical period, in aggregate, and broken down by calendar month. In addition, surplus-water mass curve data were tabulated for each of the lakes. Monthly order statistics of computed withdrawals indicated that, for the three pumping capacities considered, increasing the target minimum flow-by amount tended to reduce the amount of water that can be withdrawn. The reduction was greatest in the lower percentiles of withdrawal; however, increasing the flow-by amount had no impact on potential withdrawals during high flow. In addition, for a given target minimum flow-by amount, increasing the pumping rate typically increased the total amount of water that could be withdrawn; however, that increase was less than a direct multiple of the increase in pumping rate for most flow statistics. Potential monthly withdrawals were observed to be more variable and more limited in some calendar months than others. Monthly order statistics and means of computed daily mean flow-by amounts indicated that flow-by amounts generally tended to be lowest during June–October. Increasing the target minimum flow-by amount for a given pumping rate resulted in some small increases in the magnitudes of the mean and 50th percentile and lower order statistics of computed mean flow-by, but had no effect on the magnitudes of the higher percentile statistics. Increasing the pumping rate for a given target minimum flow-by amount resulted in decreases in magnitudes of higher-percentile flow-by statistics by an amount equal to the flow equivalent of the increase in pumping rate; however, some lower percentile statistics remained unchanged.

Combining Radar and Daily Precipitation Data to Estimate Meaningful Sub-daily Precipitation Extremes

NASA Astrophysics Data System (ADS)

Pegram, G. G. S.; Bardossy, A.

2016-12-01

Short duration extreme rainfalls are important for design. The purpose of this presentation is not to improve the day by day estimation of precipitation, but to obtain reasonable statistics for the subdaily extremes at gauge locations. We are interested specifically in daily and sub-daily extreme values of precipitation at gauge locations. We do not employ the common procedure of using time series of control station to determine the missing data values in a target. We are interested in individual rare events, not sequences. The idea is to use radar to disaggregate daily totals to sub-daily amounts. In South Arica, an S-band radar operated relatively continuously at Bethlehem from 1998 to 2003, whose scan at 1.5 km above ground [CAPPI] overlapped a dense (10 km spacing) set of 45 pluviometers recording in the same 6-year period. Using this valuable set of data, we are only interested in rare extremes, therefore small to medium values of rainfall depth were neglected, leaving 12 days of ranked daily maxima in each set per year, whose sum typically comprised about 50% of each annual rainfall total. The method presented here uses radar for disaggregating daily gauge totals in subdaily intervals down to 15 minutes in order to extract the maxima of sub-hourly through to daily rainfall at each of 37 selected radar pixels [1 km square in plan] which contained one of the 45 pluviometers not masked out by the radar foot-print. The pluviometer data were aggregated to daily totals, to act as if they were daily read gauges; their only other task was to help in the cross-validation exercise. The extrema were obtained as quantiles by ordering the 12 daily maxima of each interval per year. The unusual and novel goal was not to obtain the reproduction of the precipitation matching in space and time, but to obtain frequency distributions of the gauge and radar extremes, by matching their ranks, which we found to be stable and meaningful in cross-validation tests. We provide and compare a range of different methodologies to enable reasonable estimation of subdaily extremes using radar and daily precipitation observations.

Research on Daily Objects Detection Based on Deep Neural Network

NASA Astrophysics Data System (ADS)

Ding, Sheng; Zhao, Kun

2018-03-01

With the rapid development of deep learning, great breakthroughs have been made in the field of object detection. In this article, the deep learning algorithm is applied to the detection of daily objects, and some progress has been made in this direction. Compared with traditional object detection methods, the daily objects detection method based on deep learning is faster and more accurate. The main research work of this article: 1. collect a small data set of daily objects; 2. in the TensorFlow framework to build different models of object detection, and use this data set training model; 3. the training process and effect of the model are improved by fine-tuning the model parameters.

Modelling of Sub-daily Hydrological Processes Using Daily Time-Step Models: A Distribution Function Approach to Temporal Scaling

NASA Astrophysics Data System (ADS)

Kandel, D. D.; Western, A. W.; Grayson, R. B.

2004-12-01

Mismatches in scale between the fundamental processes, the model and supporting data are a major limitation in hydrologic modelling. Surface runoff generation via infiltration excess and the process of soil erosion are fundamentally short time-scale phenomena and their average behaviour is mostly determined by the short time-scale peak intensities of rainfall. Ideally, these processes should be simulated using time-steps of the order of minutes to appropriately resolve the effect of rainfall intensity variations. However, sub-daily data support is often inadequate and the processes are usually simulated by calibrating daily (or even coarser) time-step models. Generally process descriptions are not modified but rather effective parameter values are used to account for the effect of temporal lumping, assuming that the effect of the scale mismatch can be counterbalanced by tuning the parameter values at the model time-step of interest. Often this results in parameter values that are difficult to interpret physically. A similar approach is often taken spatially. This is problematic as these processes generally operate or interact non-linearly. This indicates a need for better techniques to simulate sub-daily processes using daily time-step models while still using widely available daily information. A new method applicable to many rainfall-runoff-erosion models is presented. The method is based on temporal scaling using statistical distributions of rainfall intensity to represent sub-daily intensity variations in a daily time-step model. This allows the effect of short time-scale nonlinear processes to be captured while modelling at a daily time-step, which is often attractive due to the wide availability of daily forcing data. The approach relies on characterising the rainfall intensity variation within a day using a cumulative distribution function (cdf). This cdf is then modified by various linear and nonlinear processes typically represented in hydrological and erosion models. The statistical description of sub-daily variability is thus propagated through the model, allowing the effects of variability to be captured in the simulations. This results in cdfs of various fluxes, the integration of which over a day gives respective daily totals. Using 42-plot-years of surface runoff and soil erosion data from field studies in different environments from Australia and Nepal, simulation results from this cdf approach are compared with the sub-hourly (2-minute for Nepal and 6-minute for Australia) and daily models having similar process descriptions. Significant improvements in the simulation of surface runoff and erosion are achieved, compared with a daily model that uses average daily rainfall intensities. The cdf model compares well with a sub-hourly time-step model. This suggests that the approach captures the important effects of sub-daily variability while utilizing commonly available daily information. It is also found that the model parameters are more robustly defined using the cdf approach compared with the effective values obtained at the daily scale. This suggests that the cdf approach may offer improved model transferability spatially (to other areas) and temporally (to other periods).

Dialyzer clearances and mass transfer-area coefficients for small solutes at low dialysate flow rates.

PubMed

Leypoldt, John K; Kamerath, Craig D; Gilson, Janice F; Friederichs, Goetz

2006-01-01

New daily hemodialysis therapies operate at low dialysate flow rates to minimize dialysate volume requirements; however, the dependence of dialyzer clearances and mass transfer-area coefficients for small solutes on dialysate flow rate under these conditions have not been studied extensively. We evaluated in vitro dialyzer clearances for urea and creatinine at dialysate flow rates of 40, 80, 120, 160, and 200 ml/min and ultrafiltration flow rates of 0, 1, and 2 l/h, using a dialyzer containing PUREMA membranes (NxStage Medical, Lawrence, MA). Clearances were measured directly across the dialyzer by perfusing bovine blood with added urea and creatinine single pass through the dialyzer at a nominal blood flow rate of 400 ml/min. Limited, additional studies were performed with the use of dialyzers containing PUREMA membranes at a blood flow rate of 200 ml/min and also with the use of other dialyzers containing polysulfone membranes (Optiflux 160NR, FMC-NA, Ogden, UT) and dialyzers containing Synphan membranes (NxStage Medical). For dialyzers containing PUREMA membranes, urea and creatinine clearances increased (p < 0.001) with increasing dialysate and ultrafiltration flow rates but were not different at blood flow rates of 200 and 400 ml/min. Dialysate saturation, defined as dialysate outlet concentration divided by blood water inlet concentration, for urea and creatinine was independent of blood and ultrafiltration flow rate but varied inversely (p < 0.001) with dialysate flow rate. Mass transfer-area coefficients for urea and creatinine were independent of blood and ultrafiltration flow rate but decreased (p < 0.001) with decreasing dialysate flow rate. Calculated mass transfer-area coefficients at low dialysate flow rates for all dialyzers tested were substantially lower than those reported by the manufacturers under conventional conditions. We conclude that dialyzers require specific characterization under relevant conditions if they are used in novel daily hemodialysis therapies at low dialysate flow rate.

Relationship of stream ecological conditions to simulated hydraulic metrics across a gradient of basin urbanization

USGS Publications Warehouse

Steuer, J.J.; Bales, J.D.; Giddings, E.M.P.

2009-01-01

The relationships among urbanization, stream hydraulics, and aquatic biology were investigated across a gradient of urbanization in 30 small basins in eastern Wisconsin, USA. Simulation of hydraulic metrics with 1-dimensional unsteady flow models was an effective means for mechanistically coupling the effects of urbanization with stream ecological conditions (i.e., algae, invertebrates, and fish). Urbanization, characterized by household, road, and urban land density, was positively correlated with the lowest shear stress for 2 adjacent transects in a reach for the low-flow summer (p < 0.001) and autumn (p < 0.01) periods. Urbanization also was positively correlated with Reynolds number and % exposed stream bed during months with moderate to low flows. Our study demonstrated the value of temporally and spatially explicit hydraulic models for providing mechanistic insight into the relationships between hydraulic variables and biological responses. For example, the positive correlation between filter-feeding invertebrate richness and minimum 2-transect shear stress observed in our study is consistent with a higher concentration of water-column particulates available for filtration. The strength of correlations between hydraulic and biological metrics is related to the time period (annual, seasonal, or monthly) considered. The hydraulic modeling approach, whether based on hourly or daily flow data, allowed documentation of the effects of a spatially variable response within a reach, and the results suggest that stream response to urbanization varies with hydraulic habitat type. ?? North American Benthological Society.

Trends in Streamflow Characteristics of Selected Sites in the Elkhorn River, Salt Creek, and Lower Platte River Basins, Eastern Nebraska, 1928-2004, and Evaluation of Streamflows in Relation to Instream-Flow Criteria, 1953-2004

USGS Publications Warehouse

Dietsch, Benjamin J.; Godberson, Julie A.; Steele, Gregory V.

2009-01-01

The Nebraska Department of Natural Resources approved instream-flow appropriations on the Platte River to maintain fish communities, whooping crane roost habitat, and wet meadows used by several wild bird species. In the lower Platte River region, the Nebraska Game and Parks Commission owns an appropriation filed to maintain streamflow for fish communities between the Platte River confluence with the Elkhorn River and the mouth of the Platte River. Because Elkhorn River flow is an integral part of the flow in the reach addressed by this appropriation, the Upper Elkhorn and Lower Elkhorn Natural Resources Districts are involved in overall management of anthropogenic effects on the availability of surface water for instream requirements. The Physical Habitat Simulation System (PHABSIM) and other estimation methodologies were used previously to determine instream requirements for Platte River biota, which led to the filing of five water appropriations applications with the Nebraska Department of Natural Resources in 1993 by the Nebraska Game and Parks Commission. One of these requested instream-flow appropriations of 3,700 cubic feet per second was for the reach from the Elkhorn River to the mouth of the Platte River. Four appropriations were granted with modifications in 1998, by the Nebraska Department of Natural Resources. Daily streamflow data for the periods of record were summarized for 17 streamflow-gaging stations in Nebraska to evaluate streamflow characteristics, including low-flow intervals for consecutive durations of 1, 3, 7, 14, 30, 60, and 183 days. Temporal trends in selected streamflow statistics were not adjusted for variability in precipitation. Results indicated significant positive temporal trends in annual flow for the period of record at eight streamflow-gaging stations - Platte River near Duncan (06774000), Platte River at North Bend (06796000), Elkhorn River at Neligh (06798500), Logan Creek near Uehling (06799500), Maple Creek near Nickerson (06800000), Elkhorn River at Waterloo (06800500), Salt Creek at Greenwood (06803555), and Platte River at Louisville (06805500). In general, sites in the Elkhorn River Basin upstream from Norfolk showed fewer significant trends than did sites downstream from Norfolk and sites in the Platte River and Salt Creek basins, where trends in low flows also were positive. Historical Platte River streamflow records for the streamflow-gaging station at Louisville, Nebraska, were used to determine the number of days per water year (Sept. 30 to Oct. 1) when flows failed to satisfy the minimum criteria of the instream-flow appropriation prior to its filing in 1993. Before 1993, the median number of days the criteria were not satisfied was about 120 days per water year. During 1993 through 2004, daily mean flows at Louisville, Nebraska, have failed to satisfy the criteria for 638 days total (median value equals 21.5 days per year). Most of these low-flow intervals occurred in summer through early fall. For water years 1953 through 2004, of the discrete intervals when flow was less that the criteria levels, 61 percent were 3 days or greater in duration, and 38 percent were 7 days or greater in duration. The median duration of intervals of flow less than the criteria levels was 4 consecutive days during 1953 through 2004.

Influence of the extreme conditions on the water quality and material exchange flux in the Strait of Istanbul

NASA Astrophysics Data System (ADS)

Altıok, Hüsne; Aslan, Aslı; Övez, Süleyman; Demirel, Nazlı; Yüksek, Ahsen; Kıratlı, Nur; Taş, Seyfettin; Müftüoğlu, Ahmet Edip; Sur, Halil Ibrahim; Okuş, Erdoğan

2014-11-01

This study focuses on the influence of extreme hydrological events on the water quality of the Strait of Istanbul (Bosphorus), a stratified waterway, polluted by sewage outfalls and non-point sources. Monthly collected water quality parameters (nitrate + nitrite, ortho-phosphate, silicate, dissolved oxygen, total suspended solids, chlorophyll-a and fecal indicator bacteria (fecal coliform and enterococci)) were evaluated together with the hydrological data (salinity, temperature and current flow) for 1 year. Two blockage events, identified as extreme conditions, were detected during the study: a lower layer blockage in February 2003 and an upper layer blockage in October 2003. During the lower layer blockage, the volume fluxes of the upper layer significantly increased to 28,140 m3 s- 1 and the lower layer almost stopped flowing (19 m3 s- 1). The dissolved oxidative nitrogen, ortho-phosphate and silicate inputs outflowing from the Black Sea were 117, 17.6, and 309 tons which were 3, 2, and 4 times the average daily fluxes respectively, in addition to enhancement of fecal indicator bacteria contamination in the sea surface flow. During the upper layer blockage, the volume flux of the upper layer was 3837 m3 s- 1 and the counter flow reached 24,985 m3 s- 1 at the northern exit of the Strait of Istanbul resulting in 2.7 fold increase in the mean bottom flow. The daily exports of nutrients, total suspended solid and dissolved oxygen by the lower layer flow increased by at least 2 fold compared to the mass fluxes estimated from the seasonal/annual means of volume flux and concentrations. On the other hand, fecal indicator bacteria flux by the lower layer inflow to the Black Sea decreased by at least 2 fold compared to the mean daily flux. These results show that the material exchange between the Marmara and the Black seas becomes more important during blockage events.

The Sponge Pump: The Role of Current Induced Flow in the Design of the Sponge Body Plan

PubMed Central

Leys, Sally P.; Yahel, Gitai; Reidenbach, Matthew A.; Tunnicliffe, Verena; Shavit, Uri; Reiswig, Henry M.

2011-01-01

Sponges are suspension feeders that use flagellated collar-cells (choanocytes) to actively filter a volume of water equivalent to many times their body volume each hour. Flow through sponges is thought to be enhanced by ambient current, which induces a pressure gradient across the sponge wall, but the underlying mechanism is still unknown. Studies of sponge filtration have estimated the energetic cost of pumping to be <1% of its total metabolism implying there is little adaptive value to reducing the cost of pumping by using “passive” flow induced by the ambient current. We quantified the pumping activity and respiration of the glass sponge Aphrocallistes vastus at a 150 m deep reef in situ and in a flow flume; we also modeled the glass sponge filtration system from measurements of the aquiferous system. Excurrent flow from the sponge osculum measured in situ and in the flume were positively correlated (r>0.75) with the ambient current velocity. During short bursts of high ambient current the sponges filtered two-thirds of the total volume of water they processed daily. Our model indicates that the head loss across the sponge collar filter is 10 times higher than previously estimated. The difference is due to the resistance created by a fine protein mesh that lines the collar, which demosponges also have, but was so far overlooked. Applying our model to the in situ measurements indicates that even modest pumping rates require an energetic expenditure of at least 28% of the total in situ respiration. We suggest that due to the high cost of pumping, current-induced flow is highly beneficial but may occur only in thin walled sponges living in high flow environments. Our results call for a new look at the mechanisms underlying current-induced flow and for reevaluation of the cost of biological pumping and its evolutionary role, especially in sponges. PMID:22180779

Setting up an atmospheric-hydrologic model for seasonal forecasts of water flow into dams in a mountainous semi-arid environment (Cyprus)

NASA Astrophysics Data System (ADS)

Camera, Corrado; Bruggeman, Adriana; Zittis, Georgios; Hadjinicolaou, Panos

2017-04-01

Due to limited rainfall concentrated in the winter months and long dry summers, storage and management of water resources is of paramount importance in Cyprus. For water storage purposes, the Cyprus Water Development Department is responsible for the operation of 56 large dams total volume of 310 Mm3) and 51 smaller reservoirs (total volume of 17 Mm3) over the island. Climate change is also expected to heavily affect Cyprus water resources with a 1.5%-12% decrease in mean annual rainfall (Camera et al., 2016) projected for the period 2020-2050, relative to 1980-2010. This will make reliable seasonal water inflow forecasts even more important for water managers. The overall aim of this study is to set-up the widely used Weather Research and Forecasting (WRF) model with its hydrologic extension (WRF-hydro), for seasonal forecasts of water inflow in dams located in the Troodos Mountains of Cyprus. The specific objectives of this study are: i) the calibration and evaluation of WRF-Hydro for the simulation of stream flows, in the Troodos Mountains, for past rainfall seasons; ii) a sensitivity analysis of the model parameters; iii) a comparison of the application of the atmospheric-hydrologic modelling chain versus the use of climate observations as forcing. The hydrologic model is run in its off-line version with daily forcing over a 1-km grid, while the overland and channel routing is performed on a 100-m grid with a time-step of 6 seconds. Model outputs are exported on a daily base. First, WRF-Hydro is calibrated and validated over two 1-year periods (October-September), using a 1-km gridded observational precipitation dataset (Camera et al., 2014) as input. For the calibration and validation periods, years with annual rainfall close to the long-term average and with the presence of extreme rainfall and flow events were selected. A sensitivity analysis is performed, for the following parameters: partitioning of rainfall into runoff and infiltration (REFKDT), the partitioning of deep percolation between losses and baseflow contribution (LOSS_BASE), water retention depth (RETDEPRTFAC), overland roughness (OVROUGHRTFAC), and channel manning coefficients (MANN). The calibrated WRF-Hydro shows a good ability to reproduce annual total streamflow (-19% error) and total peak discharge volumes (+3% error), although very high values of MANN were used to match the timing of the peak and get positive values of Nash-Sutcliffe efficiency coefficient (0.13). The two most sensitive parameters for the modeled seasonal flow were REFKDT and LOSS_BASE. Simulations of the calibrated WRF-Hydro with WRF modelled atmospheric forcing showed high errors in comparison with those forced with observations, which can be corrected only by modifying the most sensitive parameters by at least one order of magnitude. This study has received funding from the EU H2020 BINGO Project (GA 641739). Camera C., Bruggeman A., Hadjinicolaou P., Pashiardis S., Lange M.A., 2016. Evaluation of interpolation techniques for the creation of gridded daily precipitation (1 × 1 km2); Cyprus, 1980-2010. J Geophys Res Atmos 119, 693-712, DOI:10.1002/2013JD020611 Camera C., Bruggeman A., Hadjinicolaou P., Michaelides S., Lange M.A., 2016. Evaluation of a spatial rainfall generator for generating high resolution precipitation projections over orographically complex terrain. Stoch Environ Res Risk Assess, DOI 10.1007/s00477-016-1239-1

Influence of declining mean annual rainfall on the behavior and yield of sediment and particulate organic carbon from tropical watersheds

NASA Astrophysics Data System (ADS)

Strauch, Ayron M.; MacKenzie, Richard A.; Giardina, Christian P.; Bruland, Gregory L.

2018-04-01

The capacity to forecast climate and land-use driven changes to runoff, soil erosion and sediment transport in the tropics is hindered by a lack of long-term data sets and model study systems. To address these issues we utilized three watersheds characterized by similar shape, geology, soils, vegetation cover, and land use arranged across a 900 mm gradient in mean annual rainfall (MAR). Using this space-for-time design, we quantified suspended sediment (SS) and particulate organic carbon (POC) export over 18 months to examine how large-scale climate trends (MAR) affect sediment supply and delivery patterns (hysteresis) in tropical watersheds. Average daily SS yield ranged from 0.128 to 0.618 t km- 2 while average daily POC ranged from 0.002 to 0.018 t km- 2. For the largest storm events, we found that sediment delivery exhibited similar clockwise hysteresis patterns among the watersheds, with no significant differences in the similarity function between watershed pairs, indicating that: (1) in-stream and near-stream sediment sources drive sediment flux; and (2) the shape and timing of hysteresis is not affected by MAR. With declining MAR, the ratio of runoff to baseflow and inter-storm length between pulse events both increased. Despite increases in daily rainfall and the number of days with large rainfall events increasing with MAR, there was a decline in daily SS yield possibly due to the exhaustion of sediment supply by frequent runoff events in high MAR watersheds. By contrast, mean daily POC yield increased with increasing MAR, possibly as a result of increased soil organic matter decomposition, greater biomass, or increased carbon availability in higher MAR watersheds. We compared results to modeled values using the Load Estimator (LOADEST) FORTRAN model, confirming the negative relationship between MAR and sediment yield. However, because of its dependency on mean daily flow, LOADEST tended to under predict sediment yield, a result of its poor ability to capture the high variability in tropical streamflow. Taken together, results indicate that declines in MAR can have contrasting effects on hydrological processes in tropical watersheds, with consequences for instream ecology, downstream water users, and nearshore habitat.

Supporting data for hydrologic studies in San Francisco Bay, California : meteorological measurements at the Port of Redwood City during 1998-2001

USGS Publications Warehouse

Schemel, Laurence E.

2002-01-01

Meteorological data were collected during 1998-2001 at the Port of Redwood City, California, to support hydrologic studies in South San Francisco Bay. The measured meteorological variables were air temperature, atmospheric pressure, quantum flux (insolation), and four parameters of wind speed and direction: scalar mean horizontal wind speed, (vector) resultant horizontal wind speed, resultant wind direction, and standard deviation of the wind direction. Hourly mean values based on measurements at five-minute intervals were logged at the site. Daily mean values were computed for temperature, infolation, pressure, and scalar wind speed. Daily mean values for 1998-2001 are described in this report, and a short record of hourly mean values is compared to data from another near-by station. Data (hourly and daily mean) from the entire period of record (starting in April 1992) and reports describing data prior to 1998 are provided.

Impacts of Land Use/Cover Uncertainty on Predictions of Ecologically Relevant Flow Metrics

NASA Astrophysics Data System (ADS)

Kalin, L.; Dosdogru, F.

2016-12-01

Streamflow regimes are crucial parts of the ecological integrity in river systems. Although species are adopted to natural flow variability, permanent changes in flow regimes as a result of alterations in land use/cover of the watersheds can adversely impact ecosystem health. This study assessed the impacts of land use/cover (LULC) changes on ecologically relevant flow (ERF) metrics in the rapidly urbanizing upper Cahaba River basin in north-central Alabama. Cahaba River is the longest free-flowing river in the state of Alabama and is identified by the Nature Conservancy as one of the only eight "Hotspot of Biodiversity" in the contiguous United States. Cahaba River and its major tributaries support 69 rare and imperiled species, making it one of the most various aquatic ecosystems in the United States. SWAT model was used to generate daily streamflows, which were then fed into the Indicators of Hydrological Alterations (IHA) software to generate 38 key ERF metrics that capture high, low, and median flow, as well as flashiness, which are known to have significant impacts on flora and fauna. SWAT was calibrated and validated twice with two different sources of LULC. Model performances during calibration and validations were very good and were very similar with both LULC. The flow duration curves generated based on each LULC also look very similar. However, when we compared the ERF metrics significant differences were observed signifying the importance of LULC sources. The biggest differences were in Oct-Dec low flows, rise and fall rates of daily flows, annual maximum flow and average during month od October. This study shows that although model calibration can compensate for the differences in differences in LULC sources, when it comes to key ERF metrics the use of the most reliable LULC source is evident.

Flow characteristics of the Clearwater River and tributaries from Clearbrook to Plummer, northwestern Minnesota

USGS Publications Warehouse

Payne, G.A.

1989-01-01

During March through October 1986, 52,560 acre-feet of water passed the continuous-record stream gaging station on the Clearwater River near Clearbrook, Minnesota, 4.8 river miles upstream from the Red Lake Indian Reservation. Flow at the downstream boundary of the Reservation totaled 93,770 acre-feet. The increase in Clearwater River flow in the reach bordering the Reservation equaled 32,950 acre-feet; 60 percent of the increase occurred during March, April, and May. During those months, flow in the Clearwater River was augmented by flow from Kiwosay Reservoir and Butcher Knife Creek, which are located on the Reservation. Daily streamflow records showed that flow in the river increased in the Reservation reach throughout the study except for 13 days during October when losses occurred. At the downstream Reservation boundary, all daily mean flows exceeded the 36 cubic feet per second minimum flow required by the Minnesota Department of Natural Resources for the gaging station at Plummer, Minnesota located 29.9 miles downstream from the Reservation boundary. Monthly flows generally followed expected seasonal trends, with the highest monthly totals occurring in April and May and the lowest monthly totals occurring during August, September, and October. Seasonal trends were modified by reservoir releases, withdrawals for irrigation, and return flows that resulted from drainage of adjacent wild-rice fields. A series of flow measurements showed that localized withdrawals and return flows at times exceeded 20 percent of total streamflow. Discharge measurements made during low flow indicated higher rates of groundwater discharge in the vicinity of the Kiwosay Reservoir than in other parts of the study reach. Measurements made during August indicated that groundwater discharge in the reach of the river bordering the Reservation resulted in a flow gain of about 20 percent. Analysis of long-term streamflow records showed that near-average hydrologic conditions prevailed during the study period.

Characterization of suspended solids and total phosphorus loadings from small watersheds in Wisconsin

USGS Publications Warehouse

Danz, Mari E.; Corsi, Steven R.; Graczyk, David J.; Bannerman, Roger T.

2010-01-01

Knowledge of the daily, monthly, and yearly distribution of contaminant loadings and streamflow can be critical for the successful implementation and evaluation of water-quality management practices. Loading data for solids (suspended sediment and total suspended solids) and total phosphorus and streamflow data for 23 watersheds were summarized for four ecoregions of Wisconsin: the Driftless Area Ecoregion, the Northern Lakes and Forests Ecoregion, the North Central Hardwoods Ecoregion, and the Southeastern Wisconsin Till Plains Ecoregion. The Northern Lakes and Forests and the North Central Hardwoods Ecoregions were combined into one region for analysis due to a lack of sufficient data in each region. Urban watersheds, all located in the Southeastern Wisconsin Till Plains, were analyzed separately from rural watersheds as the Rural Southeastern Wisconsin Till Plains region and the Urban Southeastern Wisconsin Till Plains region. Results provide information on the distribution of loadings and streamflow between base flow and stormflow, the timing of loadings and streamflow throughout the year, and information regarding the number of days in which the majority of the annual loading is transported. The average contribution to annual solids loading from stormflow periods for the Driftless Area Ecoregion was 84 percent, the Northern Lakes and Forests/North Central Hardwoods region was 71 percent, the Rural Southeastern Wisconsin Till Plains region was 70 percent, and the Urban Southeastern Wisconsin Till Plains region was 90 percent. The average contributions to annual total phosphorus loading from stormflow periods were 72, 49, 61, and 76 percent for each of the respective regions. The average contributions to annual streamflow from stormflow periods are 20, 23, 31, and 50 percent for each of the respective regions. In all regions, the most substantial loading contributions for solids were in the late winter (February through March), spring (April through May), and early summer (June through July), with fall (October through November) and early winter (December through January) contributing the smallest loadings. The Northern Lakes and Forests/North Central Hardwoods region had some substantial loading in September. There was a similar pattern for total phosphorus loading in all regions, with the pattern somewhat less pronounced in urban watersheds. As with the loading results, average monthly streamflow values were greatest in late winter, spring, and early summer, with the lowest values typically in fall and early winter. Loading contributions were greater from stormflow than from base flow in all instances, except total phosphorus in the Northern Lakes and Forests/North Central Hardwoods region, which had equal or greater base-flow contribution for several months. Base flow constituted a greater percentage of the total streamflow than stormflow in all rural watersheds for all regions. Only a few storms each year dominated the annual loading totals for solids and total phosphorus. When daily loading values were ranked for the year, all regions reached 50 percent of the annual solids loading in the 5 highest loading days and nearly 50 percent of the annual total phosphorus loading in the 14 highest loading days.

Behavioural and physiological responses of brook trout Salvelinus fontinalis to midwinter flow reduction in a small ice-free mountain stream.

PubMed

Krimmer, A N; Paul, A J; Hontela, A; Rasmussen, J B

2011-09-01

This study presents an experimental analysis of the effects of midwinter flow reduction (50-75%, reduction in discharge in 4 h daily pulses) on the physical habitat and on behaviour and physiology of overwintering brook trout Salvelinus fontinalis in a small mountain stream. Flow reduction did not result in significant lowering of temperature or formation of surface or subsurface ice. The main findings were (1) daily movement by S. fontinalis increased (c. 2·5-fold) during flow reduction, but was limited to small-scale relocations (<10 m). (2) Undercut banks were the preferred habitat and availability of these habitats was reduced during flow reduction. (3) Although both experimental and reference fish did lose mass and condition during the experiment, no effects of flow reduction on stress indicators (blood cortisol or glucose) or bioenergetics (total body fat, water content or mass loss) were detected, probably because access to the preferred type of cover remained available. Like other salmonids, S. fontinalis moves little and seeks physical cover during winter. Unlike many of the more studied salmonids, however, this species overwinters successfully in small groundwater-rich streams that often remain ice-free, and this study identifies undercut banks as the critical winter habitat rather than substratum cover. © 2011 The Authors. Journal of Fish Biology © 2011 The Fisheries Society of the British Isles.

26 CFR 1.1411-6 - Income on investment of working capital subject to tax.

Code of Federal Regulations, 2014 CFR

2014-04-01

... current obligations with cash flow generated by the restaurant. S utilizes an interest-bearing checking account at a local bank to make daily deposits of cash receipts generated by the restaurant, and also to... significantly more or less than this amount depending on the short-term cash flow needs of the business. In...

78 FR 79061 - Noise Exposure Map Notice; Key West International Airport, Key West, FL

Federal Register 2010, 2011, 2012, 2013, 2014

2013-12-27

..., Flight Track Utilization by Aircraft Category for East Flow Operations; Table 4-3, Flight Track Utilization by Aircraft Category for West Flow Operations; Table 4-4, 2013 Air Carrier Flight Operations; Table 4-5, 2013 Commuter and Air Taxi Flight Operations; Table 4-6, 2013 Average Daily Engine Run-Up...

Simulating the effect of climate extremes on groundwater flow through a lakebed

USGS Publications Warehouse

Virdi, Makhan L.; Lee, Terrie M.; Swancar, Amy; Niswonger, Richard G.

2012-01-01

Groundwater exchanges with lakes resulting from cyclical wet and dry climate extremes maintain lake levels in the environment in ways that are not well understood, in part because they remain difficult to simulate. To better understand the atypical groundwater interactions with lakes caused by climatic extremes, an original conceptual approach is introduced using MODFLOW-2005 and a kinematic-wave approximation to variably saturated flow that allows lake size and position in the basin to change while accurately representing the daily lake volume and three-dimensional variably saturated groundwater flow responses in the basin. Daily groundwater interactions are simulated for a calibrated lake basin in Florida over a decade that included historic wet and dry departures from the average rainfall. The divergent climate extremes subjected nearly 70% of the maximum lakebed area and 75% of the maximum shoreline perimeter to both groundwater inflow and lake leakage. About half of the lakebed area subject to flow reversals also went dry. A flow-through pattern present for 73% of the decade caused net leakage from the lake 80% of the time. Runoff from the saturated lake margin offset the groundwater deficit only about half of that time. A centripetal flow pattern present for 6% of the decade was important for maintaining the lake stage and generated 30% of all net groundwater inflow. Pumping effects superimposed on dry climate extremes induced the least frequent but most cautionary flow pattern with leakage from over 90% of the actual lakebed area.

78 FR 72099 - Agency Information Collection Activities: Submitted for Office of Management and Budget Review...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-12-02

... from leases in California or Alaska. Value is the average of the daily mean ANS spot prices published.... . . . (1) To calculate the daily mean spot price . . . (2) Use only the days . . . (3) You must adjust the... to your refinery and the NYMEX 330 2 660 price or ANS spot price is an unreasonable value. (1...

78 FR 14824 - Agency Information Collection Activities: Submitted for Office of Management and Budget Review...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-03-07

... Alaska. Value is the average of the daily mean ANS spot prices published in any ONRR-approved publication during the trading month most concurrent with the production month. (1) To calculate the daily mean spot... ANS spot price is an unreasonable value. (1) . . . you may apply to the ONRR Director to establish a...

Energy Expended by Adults with and without Intellectual Disabilities during Activities of Daily Living

ERIC Educational Resources Information Center

Lante, Kerrie; Reece, John; Walkley, Jeff

2010-01-01

The aims of this study were to (1) determine the energy expenditure of adults with and without intellectual disabilities during common activities of daily living (ADL), (2) use these values to evaluate the accuracy of equivalent activity values reported in the Compendium of Physical Activities (CPA), and (3) identify ADL that may confer a health…

40 CFR 418.32 - Effluent limitations guidelines representing the degree of effluent reduction attainable by the...

Code of Federal Regulations, 2013 CFR

2013-07-01

... AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS FERTILIZER MANUFACTURING POINT SOURCE CATEGORY Urea... daily values for 30 consecutive days shall not exceed— Ammonia (as N) 0.95 0.48 Organic nitrogen (as N...) Maximum for any 1 day Average of daily values for 30 consecutive days shall not exceed— Ammonia (as N) 1...

40 CFR 418.32 - Effluent limitations guidelines representing the degree of effluent reduction attainable by the...

Code of Federal Regulations, 2014 CFR

2014-07-01

... AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS FERTILIZER MANUFACTURING POINT SOURCE CATEGORY Urea... daily values for 30 consecutive days shall not exceed— Ammonia (as N) 0.95 0.48 Organic nitrogen (as N...) Maximum for any 1 day Average of daily values for 30 consecutive days shall not exceed— Ammonia (as N) 1...

40 CFR 418.32 - Effluent limitations guidelines representing the degree of effluent reduction attainable by the...

Code of Federal Regulations, 2012 CFR

2012-07-01

... AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS FERTILIZER MANUFACTURING POINT SOURCE CATEGORY Urea... daily values for 30 consecutive days shall not exceed— Ammonia (as N) 0.95 0.48 Organic nitrogen (as N...) Maximum for any 1 day Average of daily values for 30 consecutive days shall not exceed— Ammonia (as N) 1...

40 CFR 418.32 - Effluent limitations guidelines representing the degree of effluent reduction attainable by the...

Code of Federal Regulations, 2011 CFR

2011-07-01

... AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS FERTILIZER MANUFACTURING POINT SOURCE CATEGORY Urea... daily values for 30 consecutive days shall not exceed— Ammonia (as N) 0.95 0.48 Organic nitrogen (as N...) Maximum for any 1 day Average of daily values for 30 consecutive days shall not exceed— Ammonia (as N) 1...

Weekend effect of O3, NO, NO2, CO and PM10 concentrations in the south of Spain during 2003-2008

NASA Astrophysics Data System (ADS)

Adame Carnero, Jose Antonio; Lozano, Antonio; Sorribas, Mar; Contreras, Juan; Ángel Hernández-Ceballos, Miguel; Godoy, Francisca; Fernández-León, Mercedes; Bolívar, Juan Pedro; de La Morena, Benito A.

2010-05-01

The weekly evolutions and the difference between labour and non-labour days for O3, NO, NO2, CO and PM10 concentrations have been analysed in the south of Spain (Andalusia). The hourly data have been collected in 70 stations (urban, suburban and rural) belong to the Air Quality Network of Andalusia. The data period used was 2003-2008. The study has been focused in order to identify the weekend effect for those pollutants. The weekly patterns has been evaluated using daily mean of O3 and CO and 90th percentile daily values of NO, NO2 and PM10. The mean daily ozone concentrations show similar values during the week days with a maximum increase of the concentrations during weekend days of 5 ?g m-3 in urban stations. The NO and NO2 levels present in general a decrease of 90th percentile daily values during weekend days. The maximum decrease observed was of 50 and 25 ?g m-3 for NO and NO2 respectively. The most of stations show similar concentrations for the mean daily CO levels during the week. In the event of PM10 while some stations present an increase of the concentrations during the weekdays others have similar values during all days with 90th percentile of 45 ?g m-3. The daily pollutants variation between week and weekend days has been evaluated from the hourly differences between weekend and week concentrations. The ozone daily evolution show negative differences from 00:00 to 5:00 local time (LT) while during the rest of the day the differences are positives. The maximum differences were registered early in the morning ranging between 4 ?g m-3 for rural stations to 14 ?g m-3 for urban stations. The NO and NO2 show positive differences between 00:00 to 7:00 (LT) with negative values within the next hours. The higher differences could reach 80 ?g m-3 for NO and 25 ?g m-3 for NO2, both in urban stations, with values lower than 10 ?g m-3and 5 ?g m-3 in suburban and rural stations respectively. The CO daily evolution show similar values in week and weekend days. The behaviour of the PM10 daily differences is similar to the observed for NO and NO2, with higher differences between 10:00 to 14:00 and values between 5 to 20 ?g m-3. The results obtained in this work point out a weak or absence for weekend effect of O3 and CO concentrations over the study area. Nevertheless, for NO, NO2 and PM10 concentrations present a decrease during the weekend. This phenomenon has been observed with more intensity over the metropolitan areas, mainly in urban stations. The results obtained in this study are being used to define the air quality plans in the south of Spain. These plans will start to apply during 2010 with the purpose to reduce the levels of these air pollutants in Andalusia.

Application of a medium-range global hydrologic probabilistic forecast scheme to the Ohio River Basin

DOE Office of Scientific and Technical Information (OSTI.GOV)

Voisin, Nathalie; Pappenberger, Florian; Lettenmaier, D. P.

2011-08-15

A 10-day globally applicable flood prediction scheme was evaluated using the Ohio River basin as a test site for the period 2003-2007. The Variable Infiltration Capacity (VIC) hydrology model was initialized with the European Centre for Medium Range Weather Forecasts (ECMWF) analysis temperatures and wind, and Tropical Rainfall Monitoring Mission Multi Satellite Precipitation Analysis (TMPA) precipitation up to the day of forecast. In forecast mode, the VIC model was then forced with a calibrated and statistically downscaled ECMWF ensemble prediction system (EPS) 10-day ensemble forecast. A parallel set up was used where ECMWF EPS forecasts were interpolated to the spatialmore » scale of the hydrology model. Each set of forecasts was extended by 5 days using monthly mean climatological variables and zero precipitation in order to account for the effect of initial conditions. The 15-day spatially distributed ensemble runoff forecasts were then routed to four locations in the basin, each with different drainage areas. Surrogates for observed daily runoff and flow were provided by the reference run, specifically VIC simulation forced with ECMWF analysis fields and TMPA precipitation fields. The flood prediction scheme using the calibrated and downscaled ECMWF EPS forecasts was shown to be more accurate and reliable than interpolated forecasts for both daily distributed runoff forecasts and daily flow forecasts. Initial and antecedent conditions dominated the flow forecasts for lead times shorter than the time of concentration depending on the flow forecast amounts and the drainage area sizes. The flood prediction scheme had useful skill for the 10 following days at all sites.« less

The Implementation and Evaluation of the Patient Admission Prediction Tool: Assessing Its Impact on Decision-Making Strategies and Patient Flow Outcomes in 2 Australian Hospitals.

PubMed

Crilly, Julia L; Boyle, Justin; Jessup, Melanie; Wallis, Marianne; Lind, James; Green, David; FitzGerald, Gerry

2015-01-01

To evaluate the implementation of a Patient Admission Prediction Tool (PAPT) in terms of patient flow outcomes and decision-making strategies. The PAPT was implemented in 2 Australian public teaching hospitals during October-December 2010 (hospital A) and October-December 2011 (hospital B). A multisite prospective, comparative (before and after) design was used. Patient flow outcomes measured included access block and hospital occupancy. Daily and weekly data were collected from patient flow reports and routinely collected emergency department information by the site champion and researchers. Daily decision-making strategies ranged from business as usual to use of overcensus beds. Weekly strategies included advanced approval to use of overcensus beds and prebooking nursing staff. These strategies resulted in improved weekend discharges to manage incoming demand for the following week. Following the introduction of the PAPT and workflow guidelines, patient access and hospital occupancy levels could be maintained despite increases in patient presentations (hospital A). The use of a PAPT, embedded in patient flow management processes and championed by a manager, can benefit bed and staff management. Further research that incorporates wider evaluation of the use of the tool at other sites is warranted.

Modeled streamflow metrics on small, ungaged stream reaches in the Upper Colorado River Basin

USGS Publications Warehouse

Reynolds, Lindsay V.; Shafroth, Patrick B.

2016-01-20

Modeling streamflow is an important approach for understanding landscape-scale drivers of flow and estimating flows where there are no streamgage records. In this study conducted by the U.S. Geological Survey in cooperation with Colorado State University, the objectives were to model streamflow metrics on small, ungaged streams in the Upper Colorado River Basin and identify streams that are potentially threatened with becoming intermittent under drier climate conditions. The Upper Colorado River Basin is a region that is critical for water resources and also projected to experience large future climate shifts toward a drying climate. A random forest modeling approach was used to model the relationship between streamflow metrics and environmental variables. Flow metrics were then projected to ungaged reaches in the Upper Colorado River Basin using environmental variables for each stream, represented as raster cells, in the basin. Last, the projected random forest models of minimum flow coefficient of variation and specific mean daily flow were used to highlight streams that had greater than 61.84 percent minimum flow coefficient of variation and less than 0.096 specific mean daily flow and suggested that these streams will be most threatened to shift to intermittent flow regimes under drier climate conditions. Map projection products can help scientists, land managers, and policymakers understand current hydrology in the Upper Colorado River Basin and make informed decisions regarding water resources. With knowledge of which streams are likely to undergo significant drying in the future, managers and scientists can plan for stream-dependent ecosystems and human water users.

Dietary intake of trace elements, minerals, and vitamins of patients on chronic hemodialysis.

PubMed

Bossola, Maurizio; Di Stasio, Enrico; Viola, Antonella; Leo, Alessandra; Carlomagno, Giusy; Monteburini, Tania; Cenerelli, Stefano; Santarelli, Stefano; Boggi, Rolando; Miggiano, Giacinto; Vulpio, Carlo; Mele, Cristina; Tazza, Luigi

2014-04-01

We aimed to estimate dietary intakes of trace elements, minerals, and vitamins in hemodialysis patients (HDP) of three centers in one metropolitan and two urban areas of Italy. Daily dietary intake was assessed using a 3-day diet diary in 128 HDP. Mean daily intakes of trace elements were as follows: zinc, 7.6 ± 5.4 mg; copper, 14.3 ± 11.8 mg; selenium, 28.3 ± 18.1 μg; and iron, 7.2 ± 4.1 mg (7.8 ± 2.6 mg in women, 6.9 ± 2.4 mg in men). The distribution of patients by daily intakes of trace elements showed most were under the recommended values, with the exception of copper intake, which was much higher. Mean daily intakes of minerals were as follows: magnesium, 174.4 ± 94.3 mg; phosphorus, 842.6 ± 576.8 mg; calcium, 371.8 ± 363.7 mg; potassium, 1,616.2 ± 897.3 mg; and sodium, 1,350 ± 1,281 mg. Mean daily intakes of vitamins were as follows: vitamin A, 486.1 ± 544.6 μg; vitamin B1, 0.86 ± 0.7 mg; vitamin B2, 1.1 ± 0.7 mg; vitamin B3, 13.3 ± 8.1 mg; vitamin C, 47.8 ± 50.3 mg; and vitamin E, 9.5 ± 3.6 mg. The distribution of patients by daily intakes of vitamins showed most were under the recommended values. Daily intakes of trace elements and vitamins were similar among the three centers and did not differ between dialysis and non-dialysis days. Many HDP have daily dietary intakes of trace elements and vitamins below the recommended values, whereas the intake of copper is much higher.

Estimating annual high-flow statistics and monthly and seasonal low-flow statistics for ungaged sites on streams in Alaska and conterminous basins in Canada

USGS Publications Warehouse

Wiley, Jeffrey B.; Curran, Janet H.

2003-01-01

Methods for estimating daily mean flow-duration statistics for seven regions in Alaska and low-flow frequencies for one region, southeastern Alaska, were developed from daily mean discharges for streamflow-gaging stations in Alaska and conterminous basins in Canada. The 15-, 10-, 9-, 8-, 7-, 6-, 5-, 4-, 3-, 2-, and 1-percent duration flows were computed for the October-through-September water year for 222 stations in Alaska and conterminous basins in Canada. The 98-, 95-, 90-, 85-, 80-, 70-, 60-, and 50-percent duration flows were computed for the individual months of July, August, and September for 226 stations in Alaska and conterminous basins in Canada. The 98-, 95-, 90-, 85-, 80-, 70-, 60-, and 50-percent duration flows were computed for the season July-through-September for 65 stations in southeastern Alaska. The 7-day, 10-year and 7-day, 2-year low-flow frequencies for the season July-through-September were computed for 65 stations for most of southeastern Alaska. Low-flow analyses were limited to particular months or seasons in order to omit winter low flows, when ice effects reduce the quality of the records and validity of statistical assumptions. Regression equations for estimating the selected high-flow and low-flow statistics for the selected months and seasons for ungaged sites were developed from an ordinary-least-squares regression model using basin characteristics as independent variables. Drainage area and precipitation were significant explanatory variables for high flows, and drainage area, precipitation, mean basin elevation, and area of glaciers were significant explanatory variables for low flows. The estimating equations can be used at ungaged sites in Alaska and conterminous basins in Canada where streamflow regulation, streamflow diversion, urbanization, and natural damming and releasing of water do not affect the streamflow data for the given month or season. Standard errors of estimate ranged from 15 to 56 percent for high-duration flow statistics, 25 to greater than 500 percent for monthly low-duration flow statistics, 32 to 66 percent for seasonal low-duration flow statistics, and 53 to 64 percent for low-flow frequency statistics.

Assessment of foetal wellbeing in pregnant women subjected to pelvic floor muscle training: a controlled randomised study.

PubMed

Okido, Marcos Massaru; Valeri, Fabiana Lellis; Martins, Wellington Paula; Ferreira, Cristine Homsi Jorge; Duarte, Geraldo; Cavalli, Ricardo Carvalho

2015-10-01

The objective was to assess foetal wellbeing in pregnant women subjected to pelvic floor muscle training (PFMT) by evaluating the acute and chronic effects of the procedure using the Doppler method. Ninety-six primigravidae with singleton pregnancies and at a low risk of pregnancy complications were randomised to either intervention with PFMT or no intervention. The final analysis included 26 women in the intervention group and 33 in the control group. Women from the intervention group were subjected to a daily PFMT program. Evidence of possible foetal risk was assessed by Doppler and the control group received standard care. The protocol was conducted from 20 to 36 weeks' gestation. The pulsatility indices (PI) of the uterine, umbilical and middle cerebral arteries were determined at 28, 32 and 36 weeks' gestation. The acute effects were determined by comparing the values obtained before and after exercise in the group subjected to PFMT and the chronic effects were determined by comparing the resting values of the trained group with those of the control group. The results obtained showed normal values for the three gestational ages in both groups, with no difference between groups. Comparison before and after exercise showed a significant decline in the PI of uterine artery at 36 weeks without changes in the flow of umbilical and middle cerebral arteries. Pelvic floor muscle training in low-risk primigravidae with singleton pregnancies was associated with a significant decline in PI of the uterine artery after exercise, while no significant changes in the flow of the middle cerebral and umbilical arteries were found. The PFMT may be recommended to women as a first-line measure to prevent of urinary incontinence during pregnancy.

The potential of different artificial neural network (ANN) techniques in daily global solar radiation modeling based on meteorological data

DOE Office of Scientific and Technical Information (OSTI.GOV)

Behrang, M.A.; Assareh, E.; Ghanbarzadeh, A.

2010-08-15

The main objective of present study is to predict daily global solar radiation (GSR) on a horizontal surface, based on meteorological variables, using different artificial neural network (ANN) techniques. Daily mean air temperature, relative humidity, sunshine hours, evaporation, and wind speed values between 2002 and 2006 for Dezful city in Iran (32 16'N, 48 25'E), are used in this study. In order to consider the effect of each meteorological variable on daily GSR prediction, six following combinations of input variables are considered: (I)Day of the year, daily mean air temperature and relative humidity as inputs and daily GSR as output.more » (II)Day of the year, daily mean air temperature and sunshine hours as inputs and daily GSR as output. (III)Day of the year, daily mean air temperature, relative humidity and sunshine hours as inputs and daily GSR as output. (IV)Day of the year, daily mean air temperature, relative humidity, sunshine hours and evaporation as inputs and daily GSR as output. (V)Day of the year, daily mean air temperature, relative humidity, sunshine hours and wind speed as inputs and daily GSR as output. (VI)Day of the year, daily mean air temperature, relative humidity, sunshine hours, evaporation and wind speed as inputs and daily GSR as output. Multi-layer perceptron (MLP) and radial basis function (RBF) neural networks are applied for daily GSR modeling based on six proposed combinations. The measured data between 2002 and 2005 are used to train the neural networks while the data for 214 days from 2006 are used as testing data. The comparison of obtained results from ANNs and different conventional GSR prediction (CGSRP) models shows very good improvements (i.e. the predicted values of best ANN model (MLP-V) has a mean absolute percentage error (MAPE) about 5.21% versus 10.02% for best CGSRP model (CGSRP 5)). (author)« less

Applications of ERTS-A Data Collection System (DCS) in the Arizona Regional Ecological Test Site (ARETS)

NASA Technical Reports Server (NTRS)

Schumann, H. H. (Principal Investigator)

1972-01-01

The author has identified the following significant results. Preliminary analysis of DCS data from the USGS Verde River stream flow measuring site indicates the DCS system is furnishing high quality data more frequently than had been expected. During the 43-day period between Nov. 3, and Dec. 15, 1972, 552 DCS transmissions were received during 193 data passes. The amount of data received far exceeded the single high quality transmission per 12-hour period expected from the DCS system. The digital-parallel ERTS-1 data has furnished sufficient to accurately compute mean daily gage heights. These in turn, are used to compute average daily streamflow rates during periods of stable or slowly changing flow conditions. The digital-parallel data has also furnished useful information during peak flow periods. However, the serial-digital DCS capability, currently under development for transmitting streamflow data, should provide data of greater utility for determining times of flood peaks.

Summary of annual mean and annual harmonic mean statistics of daily mean streamflow for 620 U.S. Geological Survey streamflow-gaging stations in Texas through water year 2007

USGS Publications Warehouse

Asquith, William H.; Heitmuller, Franklin T.

2008-01-01

Analysts and managers of surface-water resources have interest in annual mean and annual harmonic mean statistics of daily mean streamflow for U.S. Geological Survey (USGS) streamflow-gaging stations in Texas. The mean streamflow represents streamflow volume, whereas the harmonic mean streamflow represents an appropriate statistic for assessing constituent concentrations that might adversely affect human health. In 2008, the USGS, in cooperation with the Texas Commission on Environmental Quality, conducted a large-scale documentation of mean and harmonic mean streamflow for 620 active and inactive, continuous-record, streamflow-gaging stations using period of record data through water year 2007. About 99 stations within the Texas USGS streamflow-gaging network are part of the larger national Hydroclimatic Data Network and are identified. The graphical depictions of annual mean and annual harmonic mean statistics in this report provide a historical perspective of streamflow at each station. Each figure consists of three time-series plots, two flow-duration curves, and a statistical summary of the mean annual and annual harmonic mean streamflow statistics for available data for each station.The first time-series plot depicts daily mean streamflow for the period 1900-2007. Flow-duration curves follow and are a graphical depiction of streamflow variability. Next, the remaining two time-series plots depict annual mean and annual harmonic mean streamflow and are augmented with horizontal lines that depict mean and harmonic mean for the period of record. Monotonic trends for the annual mean streamflow and annual harmonic mean streamflow also are identified using Kendall's tau, and the slope of the trend is depicted using the nonparametric (linear) Theil-Sen line, which is only drawn for p-values less than .10 of tau. The history of annual mean and annual harmonic mean streamflow of one or more streamflow-gaging stations could be used in a watershed, river basin, or other regional context by analysts and managers of surface-water resources to guide scientific, regulatory, or other inquiries of streamflow conditions in Texas.

Improving asthma control through telemedicine: a study of short-message service.

PubMed

Ostojic, Vedran; Cvoriscec, Branimir; Ostojic, Sanja Barsic; Reznikoff, Dimitry; Stipic-Markovic, Asja; Tudjman, Zdenko

2005-02-01

Home peak expiratory flow (PEF) measurement is recommended by asthma guidelines. In a 16-week randomized controlled study on 16 subjects with asthma (24.6 6.5 years old, asthma duration small ze, Cyrillic 6 months), we examined Global System for Mobile Communications (GSM) mobile telephone short-message service (SMS) as a novel means of telemedicine in PEF monitoring. All subjects received asthma education, self-management plan, and standard treatment. All measured PEF three times daily and kept a symptom diary. In the study group, therapy was adjusted weekly by an asthma specialist according to PEF values received daily from the patients. There was no significant difference between the groups in absolute PEF, but PEF variability was significantly smaller in the study group (16.12 +/- 6.93% vs. 27.24 +/- 10.01%, p = 0.049). forced expiratory flow in 1 second (FEV1; % predicted) in the study group was slightly but significantly increased (81.25 +/- 17.31 vs. 77.63 +/- 14.80, p = 0.014) and in the control group, unchanged (78.25 +/- 21.09 vs. 78.88 +/- 22.02, p = 0.497). Mean FEV1 was similar in the two groups both before and after the study. Controls had significantly higher scores for cough (1.85 +/- 0.43 vs. 1.42 +/- 0.28, p < 0.05) and night symptoms (1.22 +/- 0.23 vs. 0.85 +/- 0.32, p < 0.05). There was no significant difference between the groups in daily consumption of inhaled medicine, forced vital capacity, or compliance. Per patient, per week, the additional cost of follow-up by SMS was Euros 1.67 (equivalent to approximately $1.30 per 1 Euro), and SMS transmission required 11.5 minutes. Although a study group of 40 patients is needed for the follow-up study to achieve the power of 80% within the 95% confidence interval, we conclude that SMS is a convenient, reliable, affordable, and secure means of telemedicine that may improve asthma control when added to a written action plan and standard follow-up.

Streamflow losses along the Balcones Fault Zone, Nueces River basin, Texas

USGS Publications Warehouse

Land, L.F.; Boning, C.W.; Harmsen, Lynn; Reeves, R.D.

1983-01-01

Statistical evaluations of historical daily flow records for the streams that have gaging stations upstream and downstream from the recharge zone provided mathematical relationships that expressed downstream flow in terms of other significant parameters. For each stream, flow entering the recharge zone is most significant in defining downstream flow; for some streams, antecedent flows at the upstream site and ground-water levels are also significantly related to downstream flow. The analyses also determined the discharges required upstream from the recharge zone to sustain flow downstream from that zone. These discharges ranged from 355 cubic feet per second for the combined Frio and Dry Frio Rivers to 33 cubic feet per second for the Nueces River. The entire flows of lesser magnitude are generally lost to recharge to the aquifer.

Probability modeling of high flow extremes in Yingluoxia watershed, the upper reaches of Heihe River basin

NASA Astrophysics Data System (ADS)

Li, Zhanling; Li, Zhanjie; Li, Chengcheng

2014-05-01

Probability modeling of hydrological extremes is one of the major research areas in hydrological science. Most basins in humid and semi-humid south and east of China are concerned for probability modeling analysis of high flow extremes. While, for the inland river basin which occupies about 35% of the country area, there is a limited presence of such studies partly due to the limited data availability and a relatively low mean annual flow. The objective of this study is to carry out probability modeling of high flow extremes in the upper reach of Heihe River basin, the second largest inland river basin in China, by using the peak over threshold (POT) method and Generalized Pareto Distribution (GPD), in which the selection of threshold and inherent assumptions for POT series are elaborated in details. For comparison, other widely used probability distributions including generalized extreme value (GEV), Lognormal, Log-logistic and Gamma are employed as well. Maximum likelihood estimate is used for parameter estimations. Daily flow data at Yingluoxia station from 1978 to 2008 are used. Results show that, synthesizing the approaches of mean excess plot, stability features of model parameters, return level plot and the inherent independence assumption of POT series, an optimum threshold of 340m3/s is finally determined for high flow extremes in Yingluoxia watershed. The resulting POT series is proved to be stationary and independent based on Mann-Kendall test, Pettitt test and autocorrelation test. In terms of Kolmogorov-Smirnov test, Anderson-Darling test and several graphical diagnostics such as quantile and cumulative density function plots, GPD provides the best fit to high flow extremes in the study area. The estimated high flows for long return periods demonstrate that, as the return period increasing, the return level estimates are probably more uncertain. The frequency of high flow extremes exhibits a very slight but not significant decreasing trend from 1978 to 2008, while the intensity of such flow extremes is comparatively increasing especially for the higher return levels.

Proxy-based reconstruction of erythemal UV doses over Estonia for 1955 2004

NASA Astrophysics Data System (ADS)

Eerme, K.; Veismann, U.; Lätt, S.

2006-08-01

A proxy-based reconstruction of the erythemally-weighted UV doses for 1955-2004 has been performed for the Tartu-Tõravere Meteorological Station (58°16' N, 26°28' E, 70 m a.s.l.) site. The pyrheliometer-measured daily sum of direct irradiance on partly cloudy and clear days, and the pyranometer-measured daily sum of global irradiance on overcast days were used as the cloudiness influence related proxies. The TOMS ozone data have been used for detecting the daily deviations from the climatic value (averaged annual cycle). In 1998-2004, the biases between the measured and reconstructed daily doses in 55.5% of the cases were within ±10% and in 83.5% of the cases within ±20%, on average. In the summer half-year these amounts were 62% and 88%, respectively. In most years the results for longer intervals did not differ significantly, if no correction was made for the daily deviations of total ozone from its climatic value. The annual and summer half-yearly erythemal doses (contributing, on average, 89% of the annual value) agreed within ±2%, except for the years after major volcanic eruptions and one extremely fine weather year (2002). Using the daily relative sunshine duration as a proxy without detailed correction for atmospheric turbidity results in biases of 2-4% in the summer half-yearly dose in the years after major volcanic eruptions and a few other years of high atmospheric turbidity. The year-to-year variations of the summer half-yearly erythemal dose in 1955-2004 were found to be within 92-111% relative to their average value. Exclusion of eight extreme years reduces this range for the remaining to 95-105.5%. Due to the quasi-periodic alternation of wet and dry periods, the interval of cloudy summers 1976-1993 regularly manifests summer half-yearly erythemal dose values lower than the 1955-2004 average. Since 1996/1997 midwinters have been darker than on average.

Getting into the musical zone: trait emotional intelligence and amount of practice predict flow in pianists

PubMed Central

Marin, Manuela M.; Bhattacharya, Joydeep

2013-01-01

Being “in flow” or “in the zone” is defined as an extremely focused state of consciousness which occurs during intense engagement in an activity. In general, flow has been linked to peak performances (high achievement) and feelings of intense pleasure and happiness. However, empirical research on flow in music performance is scarce, although it may offer novel insights into the question of why musicians engage in musical activities for extensive periods of time. Here, we focused on individual differences in a group of 76 piano performance students and assessed their flow experience in piano performance as well as their trait emotional intelligence. Multiple regression analysis revealed that flow was predicted by the amount of daily practice and trait emotional intelligence. Other background variables (gender, age, duration of piano training and age of first piano training) were not predictive. To predict high achievement in piano performance (i.e., winning a prize in a piano competition), a seven-predictor logistic regression model was fitted to the data, and we found that the odds of winning a prize in a piano competition were predicted by the amount of daily practice and the age at which piano training began. Interestingly, a positive relationship between flow and high achievement was not supported. Further, we explored the role of musical emotions and musical styles in the induction of flow by a self-developed questionnaire. Results suggest that besides individual differences among pianists, specific structural and compositional features of musical pieces and related emotional expressions may facilitate flow experiences. Altogether, these findings highlight the role of emotion in the experience of flow during music performance and call for further experiments addressing emotion in relation to the performer and the music alike. PMID:24319434

Low-flow characteristics and flow-duration statistics for selected USGS continuous-record streamgaging stations in North Carolina through 2012

USGS Publications Warehouse

Weaver, J. Curtis

2015-03-12

In 2013, the U.S. Geological Survey, in cooperation with the North Carolina Division of Water Resources, compiled updated low-flow characteristics and flow-duration statistics for selected continuous-record streamgages in North Carolina. The compilation of updated streamflow statistics provides regulators and planners with relevant hydrologic information reflective of the recent droughts, which can be used to better manage the quantity and quality of streams in North Carolina. Streamflow records available through the 2012 water year1 were used to determine the annual (based on climatic year2) and winter 7-day, 10-year (7Q10, W7Q10) low-flow discharges, the 30-day, 2-year (30Q2) low-flow discharge, and the 7-day, 2-year (7Q2) low-flow discharge. Consequently, streamflow records available through March 31, 2012 (or the 2011 climatic year) were used to determine the updated low-flow characteristics. Low-flow characteristics were published for 177 unregulated sites, 56 regulated sites, and 33 sites known or considered to be affected by varying degrees of minor regulation and (or) diversions upstream from the streamgages (266 sites total). The updated 7Q10 discharges were compared for 63 streamgages across North Carolina where (1) long-term streamflow record consisted of 30 or more climatic years of data available as of the 1998 climatic year, and (2) streamflows were not known to be regulated. The 7Q10 discharges did not change for 3 sites, whereas increases and decreases were noted at 5 and 55 sites, respectively. Positive changes (increases) ranged from 4.3 percent (site 362) to 34.1 percent (site 112) with a median of 13.2 percent. Negative percentage changes (decreases) ranged from –3.3 percent (site 514) to –80.0 percent (site 308) with a median of –22.2 percent. The median percentage change for all 63 streamgages was –18.4 percent. Streamflow statistics determined as a part of this compilation included minimum, mean, maximum, and flow-duration statistics of daily mean discharges for categorical periods. Flow-duration statistics based on the daily mean discharge records were compiled in this study for the 5th, 10th, 25th, 50th, 75th, 90th, and 95th percentiles. Flow-duration statistics were determined for each complete water year of record at a streamgage as well as the available period of record (or selected periods if flows were regulated) and selected seasonal, monthly, and calendar day periods. In addition to the streamflow statistics compiled for each of the water years, the number of days the daily mean discharge was at or below the 10th percentile was summed for each water year as well as the number of events during the water year when streamflow was consistently at or below the 10th percentile. All low-flow characteristics for the streamgages were added into the StreamStatsDB, which is a database accessible to users through the recently released USGS StreamStats application for North Carolina. The minimum, mean, maximum, and flow-duration statistics of daily mean discharges based on the available (or selected if regulated flows) period of record were updated in the North Carolina StreamStatsDB. However, for the selected seasonal, monthly, calendar day, and annual water year periods, tab-delimited American Standard Code for Information Interchange (ASCII) tables of the streamflow statistics are available online to users from a link provided in the StreamStats application. 1The annual period from October 1 through September 30, designated by the year in which the period ends. 2The annual period from April 1 through March 31, designated by the year in which the period begins.

Dual-test monitoring of hyperglycemia using daily glucose and weekly fructosamine values.

PubMed

Carter, A W; Borchardt, N; Cooney, M; Greene, D

2001-01-01

The purpose of this study was to assess the impact of using a dual-test blood glucose/fructosamine home monitoring system to assist individuals identified as having the potential for poor glycemic control to achieve values closer to normal. Forty-eight subjects found to have a fasting blood glucose value of > or = 126 mg/dL, casual blood glucose value of > or = 140 mg/dL, and/or blood fructosamine value of > or = 310 micromol/L, agreed to perform daily self testing for 90 days and were provided a dual-test blood glucose/fructosamine home monitoring system and testing supplies at no charge to them. Medication changes/compliance along with dietary and exercise habits were compared to testing results by the principle investigator at approximate 30-day intervals. The desired goal of this project was to achieve and/or maintain a fasting blood glucose value of < or = 110 mg/dL, a casual blood glucose value of < or = 140 mg/dL and a blood fructosamine value of < or = 310 micromol/L by encouraging each individual to realize the effect of dietary intake and exercise habits, and understand the importance of medication compliance, if appropriate, in achieving better overall glycemic control. Four subjects withdrew from the study prior to completion, 11 of the remaining 44 completed 60 days of testing and 33 of 44 completed 90 days of testing. Regular monitoring and counseling achieved an average reduction in blood glucose of 27.5% and a 16.6% reduction in average blood fructosamine when compared to original screening results of these 44 individuals. This study indicates that the addition of weekly fructosamine values to daily blood glucose values provides both the patient and clinician valuable information to evaluate the impact of dietary, exercise, and medication therapy changes on glycemic control by bridging the existing gap between daily blood glucose values and quarterly HbA1c confirmation of intervention results.

Decreased Peak Expiratory Flow Associated with Muscle Fiber-Type Switching in Spinal and Bulbar Muscular Atrophy

PubMed Central

Yamada, Shinichiro; Hashizume, Atsushi; Hijikata, Yasuhiro; Inagaki, Tomonori; Suzuki, Keisuke; Kondo, Naohide; Kawai, Kaori; Noda, Seiya; Nakanishi, Hirotaka; Banno, Haruhiko; Hirakawa, Akihiro; Koike, Haruki; Halievski, Katherine; Jordan, Cynthia L.; Katsuno, Masahisa; Sobue, Gen

2016-01-01

The aim of this study was to characterize the respiratory function profile of subjects with spinal and bulbar muscular atrophy (SBMA), and to explore the underlying pathological mechanism by comparing the clinical and biochemical indices of this disease with those of amyotrophic lateral sclerosis (ALS). We enrolled male subjects with SBMA (n = 40) and ALS (n = 25) along with 15 healthy control subjects, and assessed their respiratory function, motor function, and muscle strength. Predicted values of peak expiratory flow (%PEF) and forced vital capacity were decreased in subjects with SBMA compared with controls. In SBMA, both values were strongly correlated with the trunk subscores of the motor function tests and showed deterioration relative to disease duration. Compared with activities of daily living (ADL)-matched ALS subjects, %PEF, tongue pressure, and grip power were substantially decreased in subjects with SBMA. Both immunofluorescence and RT-PCR demonstrated a selective decrease in the expression levels of the genes encoding the myosin heavy chains specific to fast-twitch fibers in SBMA subjects. The mRNA levels of peroxisome proliferator-activated receptor gamma coactivator 1-alpha and peroxisome proliferator-activated receptor delta were up-regulated in SBMA compared with ALS and controls. In conclusion, %PEF is a disease-specific respiratory marker for the severity and progression of SBMA. Explosive muscle strength, including %PEF, was selectively affected in subjects with SBMA and was associated with activation of the mitochondrial biogenesis-related molecular pathway in skeletal muscles. PMID:28005993

Box Model of a Series of Salt Ponds, as Applied to the Alviso Salt Pond Complex, South San Francisco Bay, California

USGS Publications Warehouse

Lionberger, Megan A.; Schoellhamer, David H.; Shellenbarger, Gregory; Orlando, James L.; Ganju, Neil K.

2007-01-01

This report documents the development and application of a box model to simulate water level, salinity, and temperature of the Alviso Salt Pond Complex in South San Francisco Bay. These ponds were purchased for restoration in 2003 and currently are managed by the U.S. Fish and Wildlife Service to maintain existing wildlife habitat and prevent a build up of salt during the development of a long-term restoration plan. The model was developed for the purpose of aiding pond managers during the current interim management period to achieve these goals. A previously developed box model of a salt pond, SPOOM, which calculates daily pond volume and salinity, was reconfigured to simulate multiple connected ponds and a temperature subroutine was added. The updated model simulates rainfall, evaporation, water flowing between the ponds and the adjacent tidal slough network, and water flowing from one pond to the next by gravity and pumps. Theoretical and measured relations between discharge and corresponding differences in water level are used to simulate most flows between ponds and between ponds and sloughs. The principle of conservation of mass is used to calculate daily pond volume and salinity. The model configuration includes management actions specified in the Interim Stewardship Plan for the ponds. The temperature subroutine calculates hourly net heat transfer to or from a pond resulting in a rise or drop in pond temperature and daily average, minimum, and maximum pond temperatures are recorded. Simulated temperature was compared with hourly measured data from pond 3 of the Napa?Sonoma Salt Pond Complex and monthly measured data from pond A14 of the Alviso Salt-Pond Complex. Comparison showed good agreement of measured and simulated pond temperature on the daily and monthly time scales.

40 CFR Appendix N to Part 50 - Interpretation of the National Ambient Air Quality Standards for PM2.5

Code of Federal Regulations, 2014 CFR

2014-07-01

... series of daily values represents the 98th percentile for that year. Creditable samples include daily... measured (or averaged from hourly measurements in AQS) from midnight to midnight (local standard time) from... design value (DV) or a 24-hour PM2.5 NAAQS DV to determine if those metrics, which are judged to be based...

75 FR 68733 - Approval and Promulgation of One-Year Extension for Attaining the 1997 8-Hour Ozone Standard for...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-11-09

... Philadelphia Area's 4th highest daily 8-hour monitored ozone value during the 2009 ozone season at each monitor...-year extensions of the attainment date if: (a) For the first 1-year extension, the area's 4th highest... second 1-year extension, the area's 4th highest daily 8-hour value, averaged over both the original...

Consumer understanding of calorie labeling: a healthy monday e-mail and text message intervention.

PubMed

Abel, Michelle L; Lee, Katherine; Loglisci, Ralph; Righter, Allison; Hipper, Thomas J; Cheskin, Lawrence J

2015-03-01

To assess caloric knowledge of participants and determine if an e-mail and/or text message intervention could increase knowledge of recommended daily caloric intake. Randomized, control trial. Johns Hopkins Hospital Cobblestone Café. The 246 participants reported eating at the Café at least twice/week. Participants randomized to control, e-mail, or text condition. The text and e-mail conditions received a message on four consecutive Mondays stating the recommended daily caloric intake. Knowledge of the government reference value of 2,000 calories. Intention-to-treat analysis was conducted. Multivariate logistic regression examined the effectiveness of text and e-mail messaging for improving knowledge of the government calorie reference value. Baseline awareness of the daily calorie reference value in study population was low. Participants in the text message condition were twice as likely to know the government calorie reference value compared to controls (p = .047, odds ratio = 2.2, 95% confidence interval [1.01, 4.73]). No significant differences were found for the e-mail condition (p = .5). Many people do not know the daily recommended caloric intake. Public education on the government calorie reference value is necessary for menu-labeling interventions to be more effective. Weekly text messaging can serve as an effective modality for delivering calorie information and nutrition education. © 2014 Society for Public Health Education.

Effect of Intermittent Energy Restriction on Flow Mediated Dilatation, a Measure of Endothelial Function: A Short Report.

PubMed

Headland, Michelle L; Clifton, Peter M; Keogh, Jennifer B

2018-06-04

Intermittent energy restriction is a popular alternative to daily energy restriction for weight loss; however, it is unknown if endothelial function, a risk factor for cardiovascular disease, is altered by periods of severe energy restriction. The objective of the study was to determine the impact of two consecutive very low energy intake days, which is the core component of the 5:2 intermittent energy restriction diet strategy, on endothelial function compared to consecutive ad libitum eating days. The secondary objective was to explore the effects of these dietary conditions on fasting glucose concentrations. This was a 4-week randomized, single-blinded, crossover study of 35 participants. Participants consumed a very low energy diet (500 calories for women, 600 calories for men) on two consecutive days per week and 5 days of habitual eating. In weeks 3 and 4 of the trial, participants had measurements of flow mediated dilatation (FMD) and blood samples taken following either 2 habitual eating days or 2 energy restricted days in a randomized order. FMD values were not different after the two eating states (8.6% vs. 8.3%, p = 0.7). All other outcome variables were unchanged. Endothelial function, as measured by flow mediated dilatation, was not altered by two consecutive very low energy intake days. Further investigations assessing the impact in specific population groups as well as different testing conditions would be beneficial.

Using Predictive Uncertainty Analysis to Assess Hydrologic Model Performance for a Watershed in Oregon

NASA Astrophysics Data System (ADS)

Brannan, K. M.; Somor, A.

2016-12-01

A variety of statistics are used to assess watershed model performance but these statistics do not directly answer the question: what is the uncertainty of my prediction. Understanding predictive uncertainty is important when using a watershed model to develop a Total Maximum Daily Load (TMDL). TMDLs are a key component of the US Clean Water Act and specify the amount of a pollutant that can enter a waterbody when the waterbody meets water quality criteria. TMDL developers use watershed models to estimate pollutant loads from nonpoint sources of pollution. We are developing a TMDL for bacteria impairments in a watershed in the Coastal Range of Oregon. We setup an HSPF model of the watershed and used the calibration software PEST to estimate HSPF hydrologic parameters and then perform predictive uncertainty analysis of stream flow. We used Monte-Carlo simulation to run the model with 1,000 different parameter sets and assess predictive uncertainty. In order to reduce the chance of specious parameter sets, we accounted for the relationships among parameter values by using mathematically-based regularization techniques and an estimate of the parameter covariance when generating random parameter sets. We used a novel approach to select flow data for predictive uncertainty analysis. We set aside flow data that occurred on days that bacteria samples were collected. We did not use these flows in the estimation of the model parameters. We calculated a percent uncertainty for each flow observation based 1,000 model runs. We also used several methods to visualize results with an emphasis on making the data accessible to both technical and general audiences. We will use the predictive uncertainty estimates in the next phase of our work, simulating bacteria fate and transport in the watershed.

Efficiency of Silver Impregnated Porous Pot (SIPP) Filters for Production of Clean Potable Water

PubMed Central

Mahlangu, Oranso; Mamba, Bhekie; Momba, Maggie

2012-01-01

The Silver Impregnated Porous Pot (SIPP) filter is a product of the Tshwane University of Technology manufactured for the production of safe drinking water at a household (home) level. Two SIPP devices were assessed for the reduction efficiency of chemical contaminants such as calcium, magnesium, iron, arsenic, fluorides and total organic carbon (TOC) as well as microbial contaminants from environmental samples. Turbidity change after filtration, together with correlation between chlorophyll a in the feed water and SIPP’s flow rates were also evaluated in order to give comprehensive guidelines on the quality of intake water that could be filtered through the filter without causing a significant decrease in flow rate. The SIPP filters removed contaminants from environmental water samples as follows: 70% to 92% iron, 36% to 68% calcium, 42% to 82% arsenic, 39% to 98% magnesium, 39% to 95% fluorides, 12% to 35% TOC and 45% to 82% turbidity. The SIPP filters had initial flow rates of 1 L/h to 4 L/h but the flow rates dropped to 0.5 L/h with an increase in cumulative volume of intake water as the filter was used. Turbidity and chemical contaminant reduction rates decreased with accumulating volume of intake water but the filter removed Ca, Fe and Mg to levels that comply with the South African National Standards (SANS 241) and the World Health Organization (WHO) guideline values. However, the SIPP filters cannot produce enough water to satisfy the daily drinking water requirement of a typical household (25 L/p·d). Chlorophyll a was associated with a decrease in the flow rate through the SIPP filters. PMID:23202668

Efficiency of Silver Impregnated Porous Pot (SIPP) filters for production of clean potable water.

PubMed

Mahlangu, Oranso; Mamba, Bhekie; Momba, Maggie

2012-08-24

The Silver Impregnated Porous Pot (SIPP) filter is a product of the Tshwane University of Technology manufactured for the production of safe drinking water at a household (home) level. Two SIPP devices were assessed for the reduction efficiency of chemical contaminants such as calcium, magnesium, iron, arsenic, fluorides and total organic carbon (TOC) as well as microbial contaminants from environmental samples. Turbidity change after filtration, together with correlation between chlorophyll a in the feed water and SIPP's flow rates were also evaluated in order to give comprehensive guidelines on the quality of intake water that could be filtered through the filter without causing a significant decrease in flow rate. The SIPP filters removed contaminants from environmental water samples as follows: 70% to 92% iron, 36% to 68% calcium, 42% to 82% arsenic, 39% to 98% magnesium, 39% to 95% fluorides, 12% to 35% TOC and 45% to 82% turbidity. The SIPP filters had initial flow rates of 1 L/h to 4 L/h but the flow rates dropped to 0.5 L/h with an increase in cumulative volume of intake water as the filter was used. Turbidity and chemical contaminant reduction rates decreased with accumulating volume of intake water but the filter removed Ca, Fe and Mg to levels that comply with the South African National Standards (SANS 241) and the World Health Organization (WHO) guideline values. However, the SIPP filters cannot produce enough water to satisfy the daily drinking water requirement of a typical household (25 L/p·d). Chlorophyll a was associated with a decrease in the flow rate through the SIPP filters.

[Humidification and heating of anesthetic gases during pediatric anesthesia using the Cicero Anesthesia Workstation].

PubMed

Strauss, J M; Hausdörfer, J; Hagemann, H; Schröder, D

1992-09-01

A series of 52 infants underwent general or urological surgery; all were ventilated with the CICERO. Two different flows of fresh gas were used. In group I (n = 21) the fresh gas flow was set exactly at the level of the minute volume, representing a half-open, non-rebreathing system. In group II (n = 31) the fresh gas flow was adjusted to 10% of the required minute volume. Temperature and relative humidity of the inspired gas were measured continuously close to the tracheal tube. Anaesthesia was accomplished with 2 vol% isoflurane, 21-30 vol% oxygen in nitrous oxide. The results were compared with those achieved with our time-tested paediatric equipment, a SERVO 900D ventilator with a Fisher-Paykel humidifier (Group III, n = 35). Using a high fresh gas flow, no increase in relative humidity in the inspired gas could be detected. The values varied between 12% and 25% (group I). Reducing the flow of fresh gas as indicated above resulted in an increase in the relative humidity (group II). Over the evaluated period of 2 h, humidity increased slowly from an initial mean value of 20% to a maximum of something over 70%. Using the SERVO 900D ventilator combined with the Fisher-Paykel humidifier, humidity reached a value of greater 90% within 10 min after activation of the heated cascade. Humidity in the inspired gas should exceed 70% to avoid damage to infant airways. This will not be attained until after more than 2 h with unaided breathing systems, by when most operations performed on paediatric patients will already be over. Condensed water may aspirated by small infants. This potentially dangerous situation was only encountered in the CICERO circuit, and not in the system protected by the Fisher-Paykel cascade. Dry gases can result in thickened mucous and in obstruction of a small tracheal tube, which requires emergency reintubation. With artificial airways dry gases damage the ciliated epithelia of the trachea and cause loss of water and body heat. The temperature of the "cold" gases varied within a range of 21-33 degrees C and could not be adjusted by the anaesthetist. In the CICERO system, heating the gases at the valve only prevents mechanical failure caused by water condensation. In pediatric anaesthesia, variable heating and non-condensing humidity are essential. The dry and heated gases of the CICERO are not acceptable in the daily practice of paediatric anaesthesia.

Steady-state balance model to calculate the indoor climate of livestock buildings, demonstrated for finishing pigs

NASA Astrophysics Data System (ADS)

Schauberger, G.; Piringer, M.; Petz, E.

The indoor climate of livestock buildings is of importance for the well-being and health of animals and their production performance (daily weight gain, milk yield etc). By using a steady-state model for the sensible and latent heat fluxes and the CO2 and odour mass flows, the indoor climate of mechanically ventilated livestock buildings can be calculated. These equations depend on the livestock (number of animals and how they are kept), the insulation of the building and the characteristics of the ventilation system (ventilation rate). Since the model can only be applied to animal houses where the ventilation systems are mechanically controlled (this is the case for a majority of finishing pig units), the calculations were done for an example of a finishing pig unit with 1000 animal places. The model presented used 30 min values of the outdoor parameters temperature and humidity, collected over a 2-year period, as input. The projected environment inside the livestock building was compared with recommended values. The duration of condensation on the inside surfaces was also calculated.

Soil temperature investigations using satellite acquired thermal-infrared data in semi-arid regions. Thesis. Final Report; [Utah

NASA Technical Reports Server (NTRS)

Day, R. L.; Petersen, G. W.

1983-01-01

Thermal-infrared data from the Heat Capacity Mapping Mission satellite were used to map the spatial distribution of diurnal surface temperatures and to estimate mean annual soil temperatures (MAST) and annual surface temperature amplitudes (AMP) in semi-arid east central Utah. Diurnal data with minimal snow and cloud cover were selected for five dates throughout a yearly period and geometrically co-registered. Rubber-sheet stretching was aided by the WARP program which allowed preview of image transformations. Daytime maximum and nighttime minimum temperatures were averaged to generation average daily temperature (ADT) data set for each of the five dates. Five ADT values for each pixel were used to fit a sine curve describing the theoretical annual surface temperature response as defined by a solution of a one-dimensinal heat flow equation. Linearization of the equation produced estimates of MAST and AMP plus associated confidence statistics. MAST values were grouped into classes and displayed on a color video screen. Diurnal surface temperatures and MAST were primarily correlated with elevation.

Analysis of trends of water quality and streamflow in the Blackstone, Branch, Pawtuxet, and Pawcatuck Rivers, Massachusetts and Rhode Island, 1979 to 2015

USGS Publications Warehouse

Savoie, Jennifer G.; Mullaney, John R.; Bent, Gardner C.

2017-02-21

Trends in long-term water-quality and streamflow data from six water-quality-monitoring stations within three major river basins in Massachusetts and Rhode Island that flow into Narragansett Bay and Little Narragansett Bay were evaluated for water years 1979–2015. In this study, conducted by the U.S. Geological Survey in cooperation with the Rhode Island Department of Environmental Management, the Rhode Island Water Resources Board, and the U.S. Environmental Protection Agency, water-quality and streamflow data were evaluated with a Weighted Regressions on Time, Discharge, and Season smoothing method, which removes the effects of year-to-year variation in water-quality conditions due to variations in streamflow (discharge). Trends in annual mean, annual median, annual maximum, and annual 7-day minimum flows at four continuous streamgages were evaluated by using a time-series smoothing method for water years 1979–2015.Water quality at all monitoring stations changed over the study period. Decreasing trends in flow-normalized nutrient concentrations and loads were observed during the period at most monitoring stations for total nitrogen, nitrite plus nitrate, and total phosphorus. Average flow-normalized loads for water years 1979–2015 decreased in the Blackstone River by up to 46 percent in total nitrogen, 17 percent in nitrite plus nitrate, and 69 percent in total phosphorus. The other rivers also had decreasing flow-normalized trends in nutrient concentrations and loads, except for the Pawtuxet River, which had an increasing trend in nitrite plus nitrate. Increasing trends in flow-normalized chloride concentrations and loads were observed during the study period at all of the rivers, with increases of more than 200 percent in the Blackstone River.Small increasing trends in annual mean daily streamflow were observed in 3 of the 4 rivers, with increases of 1.2 to 11 percent; however, the trends were not significant. All 4 rivers had decreases in streamflow for the annual 7-day minimums, but only 3 of the 4 rivers had decreases that were significant (34 to 54 percent). The Branch River had decreasing annual mean daily streamflow (7.5 percent) and the largest decrease in the annual 7-day minimum streamflow. The Blackstone and Pawtuxet Rivers had the largest increases in annual maximum daily flows but had decreases in the annual 7-day minimum flows.

Quantifying changes in the contribution of upstream snow and glacier melt to downstream low flows in the River Rhine

NASA Astrophysics Data System (ADS)

Stahl, K.; Kohn, I.; Boehm, M.; Seibert, J.; Freudiger, D.; Gerlinger, K.; Weiler, M.

2016-12-01

Low flows impact river ecosystems and impair water use. In the mid- and downstream reaches of one of the largest rivers in Europe, the River Rhine, low flows can threaten a variety of ecosystem services and direct uses. Low flows in summer and fall are sustained by the snow and ice melt contribution from the glacierized mountain headwaters upstream. This study explores changes in the discharge components of rain, snowmelt and ice melt during extreme low flow events from a downstream perspective. Quantification of the discharge components is based on a novel method of runoff component tracking that was implemented into a model chain, consisting of the HBV model, which includes a glacier mass balance model allowing for areal glacier changes, for the headwaters and the distributed hydrological model LARSIM for the remaining Rhine basin. A transient model run at daily resolution was calibrated to glacier volume change, basin-wide snow cover and snow water equivalent and discharge variability at many gauging stations over the period 1901-2006. The analysis of the resulting discharge components revealed that over the course of the 20th Century, the loss of glacier volume and glacier area in the headwaters appears to have compensated an increasingly negative glacier mass balance, resulting in little long-term change to the ice melt component in summer streamflow - thus showing no clear `peak-water' trend. While the glacier ice melt component was less than two percent of the average annual discharge of the mid and lower reaches of the River Rhine, models suggest its fraction was much higher during extreme low flow events. The low flows of the summers of 1921, 1947, and 2003 were comprised of record daily ice melt fractions of more than one fifth of the daily discharge along the mid and lower reaches from Basel to the mouth. A scenario model run with suppressed glacier area change suggests that the ice melt discharge component would have doubled if the same meteorological event as in 2003 had occurred in the early 1900s when glacier areas were still much larger. Impacts on ecology and water use most likely would have also been less severe. The modeled changes in discharge components thus allow a quantification of the low flow hazard that may loom ahead as the glaciers continue to decline.

On a Model of a Nonlinear Feedback System for River Flow Prediction

NASA Astrophysics Data System (ADS)

Ozaki, T.

1980-02-01

A nonlinear system with feedback is proposed as a dynamic model for the hydrological system, whose input is the rainfall and whose output is the discharge of river flow. Parameters and orders of the model are estimated using Akaike's information criterion. Its application to the prediction of daily discharges of Kanna River and Bird Creek is discussed.

Predicting Average Vehicle Speed in Two Lane Highways Considering Weather Condition and Traffic Characteristics

NASA Astrophysics Data System (ADS)

Mirbaha, Babak; Saffarzadeh, Mahmoud; AmirHossein Beheshty, Seyed; Aniran, MirMoosa; Yazdani, Mirbahador; Shirini, Bahram

2017-10-01

Analysis of vehicle speed with different weather condition and traffic characteristics is very effective in traffic planning. Since the weather condition and traffic characteristics vary every day, the prediction of average speed can be useful in traffic management plans. In this study, traffic and weather data for a two-lane highway located in Northwest of Iran were selected for analysis. After merging traffic and weather data, the linear regression model was calibrated for speed prediction using STATA12.1 Statistical and Data Analysis software. Variables like vehicle flow, percentage of heavy vehicles, vehicle flow in opposing lane, percentage of heavy vehicles in opposing lane, rainfall (mm), snowfall and maximum daily wind speed more than 13m/s were found to be significant variables in the model. Results showed that variables of vehicle flow and heavy vehicle percent acquired the positive coefficient that shows, by increasing these variables the average vehicle speed in every weather condition will also increase. Vehicle flow in opposing lane, percentage of heavy vehicle in opposing lane, rainfall amount (mm), snowfall and maximum daily wind speed more than 13m/s acquired the negative coefficient that shows by increasing these variables, the average vehicle speed will decrease.

A precipitation-runoff model for the analysis of the effects of water withdrawals and land-use change on streamflow in the Usquepaug-Queen River Basin, Rhode Island

USGS Publications Warehouse

Zarriello, Phillip J.; Bent, Gardner C.

2004-01-01

The 36.1-square-mile UsquepaugQueen River Basin in south-central Rhode Island is an important water resource. Streamflow records indicate that withdrawals may have diminished flows enough to affect aquatic habitat. Concern over the effect of withdrawals on streamflow and aquatic habitat prompted the development of a Hydrologic Simulation ProgramFORTRAN (HSPF) model to evaluate the water-management alternatives and land-use change in the basin. Climate, streamflow, and water-use data were collected to support the model development. A logistic-regression equation was developed for long-term simulations to predict the likelihood of irrigation, the primary water use in the basin, from antecedent potential evapotranspiration and precipitation for generating irrigation demands. The HSPF model represented the basin by 13 pervious-area and 2 impervious-area land-use segments and 20 stream reaches. The model was calibrated to the period January 1, 2000 to September 30, 2001, at three continuous streamflow-gaging stations that monitor flow from 10, 54, and 100 percent of the basin drainage area. Hydrographs and flow-duration curves of observed and simulated discharges, along with statistics compiled for various model-fit metrics, indicate a satisfactory model performance. The calibrated HSPF model was modified to evaluate streamflow (1) under no withdrawals to streamflow under current (200001) withdrawal conditions under long-term (19602001) climatic conditions, (2) under withdrawals by the former Ladd School water-supply wells, and (3) under fully developed land use. The effects of converting from direct-stream withdrawals to ground-water withdrawals were evaluated outside of the HSPF model by use of the STRMDEPL program, which calculates the time delayed response of ground-water withdrawals on streamflow depletion. Simulated effects of current withdrawals relative to no withdrawals indicate about a 20-percent decrease in the lowest mean daily streamflows at the basin outlet, but withdrawals have little effect on flows that are exceeded less than about 90 percent of the time. Tests of alternative model structures to evaluate model uncertainty indicate that the lowest mean daily flows ranged between 3 and 5 cubic feet per second (ft3/s) without withdrawals and 2.2 to 4 ft3/s with withdrawals. Changes in the minimum daily streamflows are more pronounced, however; at the upstream streamflow-gaging station, a minimum daily flow of 0.2 ft3/s was sustained without withdrawals, but simulations with withdrawals indicate that the reach would stop flowing part of a day about 5 percent of the time. The effect on streamflow of potential ground-water withdrawals of 0.20, 0.90, and 1.78 million gallons per day (Mgal/d) at the former Ladd School near the central part of the basin were evaluated. The lowest daily mean flows in model reach 3, the main stem of the Queen River closest to the pumped wells, decreased by about 50 percent for withdrawals of 0.20 Mgal/d (from about 0.4 to 0.2 ft3/s) in comparison to current withdrawals. Reach 3 would occasionally stop flowing during part of the day at the 0.20-Mgal/d withdrawal rate because of diurnal fluctuation in streamflow. The higher withdrawal rates (0.90 and 1.78 Mgal/d) would cause reach 3 to stop flowing about 10 to 20 percent of the time, but the effects of pumping rapidly diminished downstream because of tributary inflows. Simulation results indicate little change in the annual 1-, 7-, and 30-day low flows at the 0.20 Mgal/d pumping rate, but at the 1.78 Mgal/d pumping rate, reach 3 stopped flowing for nearly a 7-day period every year and for a 30-day period about every other year. At the 0.90 Mgal/d pumping rate, reach 3 stopped flowing about every other year for a 7-day period and about once every 5 years for a 30-day period. Land-use change was simulated by converting model hydrologic-response units (HRUs) representing undeveloped areas to HRUs representing developed areas o

Water-use dynamics of an alien-invaded riparian forest within the Mediterranean climate zone of the Western Cape, South Africa

NASA Astrophysics Data System (ADS)

Scott-Shaw, Bruce C.; Everson, Colin S.; Clulow, Alistair D.

2017-09-01

In South Africa, the invasion of riparian forests by alien trees has the potential to affect the country's limited water resources. Tree water-use measurements have therefore become an important component of recent hydrological studies. It is difficult for South African government initiatives, such as the Working for Water (WfW) alien clearing program, to justify alien tree removal and implement rehabilitation unless hydrological benefits are known. Consequently, water use within a riparian forest along the Buffeljags River in the Western Cape of South Africa was monitored over a 3-year period. The site consisted of an indigenous stand of Western Cape afrotemperate forest adjacent to a large stand of introduced Acacia mearnsii. The heat ratio method of the heat pulse velocity sap flow technique was used to measure the sap flow of a selection of indigenous species in the indigenous stand, a selection of A. mearnsii trees in the alien stand and two clusters of indigenous species within the alien stand. The indigenous trees in the alien stand at Buffeljags River showed significant intraspecific differences in the daily sap flow rates varying from 15 to 32 L day-1 in summer (sap flow being directly proportional to tree size). In winter (June), this was reduced to only 7 L day-1 when limited energy was available to drive the transpiration process. The water use in the A. mearnsii trees showed peaks in transpiration during the months of March 2012, September 2012 and February 2013. These periods had high average temperatures, rainfall and high daily vapor pressure deficits (VPDs - average of 1.26 kPa). The average daily sap flow ranged from 25 to 35 L in summer and approximately 10 L in the winter. The combined accumulated daily sap flow per year for the three Vepris lanceolata and three A. mearnsii trees was 5700 and 9200 L, respectively, clearly demonstrating the higher water use of the introduced Acacia trees during the winter months. After spatially upscaling the findings, it was concluded that, annually, the alien stand used nearly 6 times more water per unit area than the indigenous stand (585 mm a-1 compared to 101 mm a-1). This finding indicates that there would be a gain in groundwater recharge and/or streamflow if the alien species are removed from riparian forests and rehabilitated back to their natural state.

Design of Environmental Flows Below Diversion Hydropower Dams: Is There Benefit to Advanced Streamflow Prediction in Sparse Data Landscapes?

NASA Astrophysics Data System (ADS)

Kibler, K. M.; Alipour, M.

2017-12-01

Diversion hydropower has been shown to significantly alter river flow regimes by dewatering diversion bypass reaches. Data scarcity is one of the foremost challenges to establishing environmental flow regimes below diversion hydropower dams, especially in regions of sparse hydro-meteorological observation. Herein, we test two prediction strategies for generating daily flows in rivers developed with diversion hydropower: a catchment similarity model, and a rainfall-runoff model selected by multi-objective optimization based on soft data. While both methods are designed for ungauged rivers embedded within large regions of sparse hydrologic observation, one is more complex and computationally-intensive. The objective of this study is to assess the benefit of using complex modeling tools in data-sparse landscapes to support design of environmental flow regimes. Models were tested in gauged catchments and then used to simulate a 28-year record of daily flows in 32 ungauged rivers. After perturbing flows with the hydropower diversion, we detect alteration using Indicators of Hydrologic Alteration (IHA) metrics and compare outcomes of the two modeling approaches. The catchment similarity model simulates low flows well (Nash-Sutcliff efficiency (NSE) = 0.91), but poorly represents moderate to high flows (overall NSE = 0.25). The multi-objective rainfall-runoff model performs well overall (NSE = 0.72). Both models agree that flow magnitudes and variability consistently decrease following diversion as temporally-dynamic flows are replaced by static minimal flows. Mean duration of events sustained below the pre-diversion Q75 and mean hydrograph rise and fall rates increase. While we see broad areas of agreement, significant effects and thresholds vary between models, particularly in the representation of moderate flows. Thus, use of simplified streamflow models may bias detected alterations or inadequately characterize pre-regulation flow regimes, providing inaccurate information as a basis for flow regime design. As an alternative, the multi-objective framework can be applied globally, and is robust to common challenges of flow prediction in ungauged rivers, such as equifinality and hydrologic dissimilarity of reference catchments.

Predictive modelling of flow in a two-dimensional intermediate-scale, heterogeneous porous media

USGS Publications Warehouse

Barth, Gilbert R.; Hill, M.C.; Illangasekare, T.H.; Rajaram, H.

2000-01-01

To better understand the role of sedimentary structures in flow through porous media, and to determine how small-scale laboratory-measured values of hydraulic conductivity relate to in situ values this work deterministically examines flow through simple, artificial structures constructed for a series of intermediate-scale (10 m long), two-dimensional, heterogeneous, laboratory experiments. Nonlinear regression was used to determine optimal values of in situ hydraulic conductivity, which were compared to laboratory-measured values. Despite explicit numerical representation of the heterogeneity, the optimized values were generally greater than the laboratory-measured values. Discrepancies between measured and optimal values varied depending on the sand sieve size, but their contribution to error in the predicted flow was fairly consistent for all sands. Results indicate that, even under these controlled circumstances, laboratory-measured values of hydraulic conductivity need to be applied to models cautiously.To better understand the role of sedimentary structures in flow through porous media, and to determine how small-scale laboratory-measured values of hydraulic conductivity relate to in situ values this work deterministically examines flow through simple, artificial structures constructed for a series of intermediate-scale (10 m long), two-dimensional, heterogeneous, laboratory experiments. Nonlinear regression was used to determine optimal values of in situ hydraulic conductivity, which were compared to laboratory-measured values. Despite explicit numerical representation of the heterogeneity, the optimized values were generally greater than the laboratory-measured values. Discrepancies between measured and optimal values varied depending on the sand sieve size, but their contribution to error in the predicted flow was fairly consistent for all sands. Results indicate that, even under these controlled circumstances, laboratory-measured values of hydraulic conductivity need to be applied to models cautiously.

Assessment of fluid distribution and flow properties in two phase fluid flow using X-ray CT technology

NASA Astrophysics Data System (ADS)

Jiang, Lanlan; Wu, Bohao; Li, Xingbo; Wang, Sijia; Wang, Dayong; Zhou, Xinhuan; Zhang, Yi

2018-04-01

To study on microscale distribution of CO2 and brine during two-phase flow is crucial for understanding the trapping mechanisms of CO2 storage. In this study, CO2-brine flow experiments in porous media were conducted using X-ray computed tomography. The porous media were packed with glass beads. The pore structure (porosity/tortuosity) and flow properties at different flow rates and flow fractions were investigated. The results showed that porosity of the packed beads differed at different position as a result of heterogeneity. The CO2 saturation is higher at low injection flow rates and high CO2 fractions. CO2 distribution at the pore scale was also visualized. ∅ Porosity of porous media CT brine_ sat grey value of sample saturated with brine CT dry grey value of sample saturated with air CT brine grey value of pure brine CT air grey value of pure air CT flow grey values of sample with two fluids occupying the pore space {CT}_{CO_2_ sat} grey value of sample saturated with CO2 {f}_{CO_2}({S}_{CO_2}) CO2 fraction {q}_{CO_2} the volume flow rate for CO2 q brine the volume flow rate for brine L Thickness of the porous media, mm L e a bundle of capillaries of equal length, mm τ Tortuosity, calculated from L e / L.

Dielectric properties of lava flows west of Ascraeus Mons, Mars

USGS Publications Warehouse

Carter, L.M.; Campbell, B.A.; Holt, J.W.; Phillips, R.J.; Putzig, N.E.; Mattei, S.; Seu, R.; Okubo, C.H.; Egan, A.F.

2009-01-01

The SHARAD instrument on the Mars Reconnaissance Orbiter detects subsurface interfaces beneath lava flow fields northwest of Ascraeus Mons. The interfaces occur in two locations; a northern flow that originates south of Alba Patera, and a southern flow that originates at the rift zone between Ascraeus and Pavonis Montes. The northern flow has permittivity values, estimated from the time delay of echoes from the basal interface, between 6.2 and 17.3, with an average of 12.2. The southern flow has permittivity values of 7.0 to 14.0, with an average of 9.8. The average permittivity values for the northern and southern flows imply densities of 3.7 and 3.4 g cm-3, respectively. Loss tangent values for both flows range from 0.01 to 0.03. The measured bulk permittivity and loss tangent values are consistent with those of terrestrial and lunar basalts, and represent the first measurement of these properties for dense rock on Mars. Copyright 2009 by the American Geophysical Union.

Applications of Extreme Value Theory in Public Health.

PubMed

Thomas, Maud; Lemaitre, Magali; Wilson, Mark L; Viboud, Cécile; Yordanov, Youri; Wackernagel, Hans; Carrat, Fabrice

2016-01-01

We present how Extreme Value Theory (EVT) can be used in public health to predict future extreme events. We applied EVT to weekly rates of Pneumonia and Influenza (P&I) deaths over 1979-2011. We further explored the daily number of emergency department visits in a network of 37 hospitals over 2004-2014. Maxima of grouped consecutive observations were fitted to a generalized extreme value distribution. The distribution was used to estimate the probability of extreme values in specified time periods. An annual P&I death rate of 12 per 100,000 (the highest maximum observed) should be exceeded once over the next 30 years and each year, there should be a 3% risk that the P&I death rate will exceed this value. Over the past 10 years, the observed maximum increase in the daily number of visits from the same weekday between two consecutive weeks was 1133. We estimated at 0.37% the probability of exceeding a daily increase of 1000 on each month. The EVT method can be applied to various topics in epidemiology thus contributing to public health planning for extreme events.

Estimation of baseline daily mean streamflows for ungaged locations on Pennsylvania streams, water years 1960-2008

USGS Publications Warehouse

Stuckey, Marla H.; Koerkle, Edward H.; Ulrich, James E.

2012-01-01

BaSE uses the map correlation method and flow-duration exceedance probability regression equations to estimate baseline daily mean streamflow for an ungaged location. The output from BaSE is a Microsoft Excel® report file that summarizes the reference streamgage and ungaged location information, including basin characteristics, percent difference in basin characteristics between the two locations, any warning associated with the basin characteristics, mean and median streamflow for the ungaged location, and a daily hydrograph of streamflow for water years 1960–2008 for the ungaged location. The daily mean streamflow for the ungaged location can be exported as a text file to be used as input into other statistical software packages. BaSE estimates daily mean streamflow for baseline conditions only, and any alterations to streamflow from regulation, large water use, or substantial mining are not reflected in the estimated streamflow.

Blending Pan-European and local hydrological models for water resource assessment in Mediterranean areas: lessons learnt from a mountainous catchment

NASA Astrophysics Data System (ADS)

José Polo, María; José Pérez-Palazón, María; Saénz de Rodrigáñez, Marta; Pimentel, Rafael; Arheimer, Berit

2017-04-01

Global hydrological models provide scientists and technicians with distributed data over medium to large areas from which assessment of water resource planning and use can be easily performed. However, scale conflicts between global models' spatial resolution and the local significant spatial scales in heterogeneous areas usually pose a constraint for the direct use and application of these models' results. The SWICCA (Service for Water Indicators in Climate Change Adaptation) Platform developed under the Copernicus Climate Change Service (C3S) offers a wide range of both climate and hydrological indicators obtained on a global scale with different time and spatial resolutions. Among the different study cases supporting the SWICCA demonstration of local impact assessment, the Sierra Nevada study case (South Spain) is a representative example of mountainous coastal catchments in the Mediterranean region. This work shows the lessons learnt during the study case development to derive local impact indicator tailored to suit the local end-users of water resource in this snow-dominated area. Different approaches were followed to select the most accurate method to downscale the global data and variables to the local level in a highly abrupt topography, in a sequential step approach. 1) SWICCA global climate variable downscaling followed by river flow simulation from a local hydrological model in selected control points in the catchment, together with 2) SWICCA global river flow values downscaling to the control points followed by corrections with local transfer functions were both tested against the available local river flow series of observations during the reference period. This test was performed for the different models and the available spatial resolutions included in the SWICCA platform. From the results, the second option, that is, the use of SWICCA river flow variables, performed the best approximations, once the local transfer functions were applied to the global values and an additional correction was performed based on the relative anomalies obtained instead of the absolute values. This approach was used to derive the future projections of selected local indicators for each end-user in the area under different climate change scenarios. Despite the spatial scale conflicts, the SWICCA river flow indicators (simulated by the E-HYPEv3.1.2 model) succeeded in approximating the observations during the reference period 1970-2000 when provided on a catchment scale, once local transfer functions and further anomaly correction were performed. Satisfactory results were obtained on a monthly scale for river flow in the main stream of the watershed, and on a daily scale for the headwater streams. The accessibility to the hydrological model WiMMed, which includes a snow module, locally validated in the study area has been crucial to downscale the SWICCA results and prove their usefulness.

Minimum number of days required for a reliable estimate of daily step count and energy expenditure, in people with MS who walk unaided.

PubMed

Norris, Michelle; Anderson, Ross; Motl, Robert W; Hayes, Sara; Coote, Susan

2017-03-01

The purpose of this study was to examine the minimum number of days needed to reliably estimate daily step count and energy expenditure (EE), in people with multiple sclerosis (MS) who walked unaided. Seven days of activity monitor data were collected for 26 participants with MS (age=44.5±11.9years; time since diagnosis=6.5±6.2years; Patient Determined Disease Steps=≤3). Mean daily step count and mean daily EE (kcal) were calculated for all combinations of days (127 combinations), and compared to the respective 7-day mean daily step count or mean daily EE using intra-class correlations (ICC), the Generalizability Theory and Bland-Altman. For step count, ICC values of 0.94-0.98 and a G-coefficient of 0.81 indicate a minimum of any random 2-day combination is required to reliably calculate mean daily step count. For EE, ICC values of 0.96-0.99 and a G-coefficient of 0.83 indicate a minimum of any random 4-day combination is required to reliably calculate mean daily EE. For Bland-Altman analyses all combinations of days, bar single day combinations, resulted in a mean bias within ±10%, when expressed as a percentage of the 7-day mean daily step count or mean daily EE. A minimum of 2days for step count and 4days for EE, regardless of day type, is needed to reliably estimate daily step count and daily EE, in people with MS who walk unaided. Copyright © 2017 Elsevier B.V. All rights reserved.

Preliminary Retrospective Analysis of Daily Tomotherapy Output Constancy Checks Using Statistical Process Control.

PubMed

Mezzenga, Emilio; D'Errico, Vincenzo; Sarnelli, Anna; Strigari, Lidia; Menghi, Enrico; Marcocci, Francesco; Bianchini, David; Benassi, Marcello

2016-01-01

The purpose of this study was to retrospectively evaluate the results from a Helical TomoTherapy Hi-Art treatment system relating to quality controls based on daily static and dynamic output checks using statistical process control methods. Individual value X-charts, exponentially weighted moving average charts, and process capability and acceptability indices were used to monitor the treatment system performance. Daily output values measured from January 2014 to January 2015 were considered. The results obtained showed that, although the process was in control, there was an out-of-control situation in the principal maintenance intervention for the treatment system. In particular, process capability indices showed a decreasing percentage of points in control which was, however, acceptable according to AAPM TG148 guidelines. Our findings underline the importance of restricting the acceptable range of daily output checks and suggest a future line of investigation for a detailed process control of daily output checks for the Helical TomoTherapy Hi-Art treatment system.

Tree and stand water fluxes of hybrid poplar clone (Populus nigra x P. maximowiczii) in short rotation coppice culture

NASA Astrophysics Data System (ADS)

Fischer, M.; Trnka, M.; Kucera, J.; Zalud, Z.

2010-09-01

This study reports on evapotranspiration and tree water use in short rotation coppice culture of hybrid poplar (Populus nigra x P. maximowiczii) for biomass energy in the Czech Republic. The high density poplar plantation (10 000 trees per ha) was established in 2003 on arable land in Czech-Moravian Highland (49°32´ N, 16°15´ E, 530 m a.s.l.) and has been coppiced in rotation period of 7 years. Firstly, evapotranspiration of the stand has been estimated by applying the Bowen ratio-energy budget method, which is considered as reliable, robust, quite simple and inexpensive technique with comparable results to eddy covariance and lysimeters. The gaps in evapotranspiration diurnal patterns caused by limitation of the bowen ratio method were filled with simple linear regression model based on relation between potential and actual evapotranspiration with regard to soil water availability and leaf area index and thus the daily, monthly and seasonal totals could be calculated. The amount of evapotranspiration during the growing season 2009 (1 March - 31 October) was 593 mm with highest monthly total 116 mm in June. Mean daily water loss over the season reached 2.43 mm per day. During the hot summer day, the maximal value 5.73 mm per day, which presented 89 % of potential evapotranspiration calculated by Penman equation, was recorded with a peak rate 0.94 mm per hour. Secondly, the transpiration was measured by sap flow tissue heat balance techniques on four individual trees with greatest stem diameters (11 - 12 cm d.b.h.) and height of 12 - 12.5 m. Relatively high transpiration values by the poplars were found during the measured part of growing season (18 June - 31 October), with maximum and mean daily transpiration of 44.41 dm3 and 16.69 dm3 per day, respectively. The seasonal transpiration of the most vigorous from the investigated individuals amounted 2542 dm3. Because in this study we didńt evaluate the transpiration of thinner trees (technical features of sap flow method dońt enable to assess trees smaller than 10 cm and bigger than 2 cm d.b.h.), scaling the transpiration to the whole stand through the relation between leaf area index, d.b.h. and the sap flow is under evaluation and results will be presented at the conference. The presentation will also include comparison between actual evapotranspiration over the reference grass surface in the immediate vicinity of the poplar plantation. The differences between the actual evapotranspiration and transpiration of the poplar stand and other special features of this bioenergy production system will be revealed in more detail. Acknowledgement: We gratefully acknowledge the support of the In-house Grant Agency at Mendel university in Brno no. IP 19/2010, In-house Grant Agency at Mendel university in Brno no. TP 11/2010 and the Research plan no. MSM6215648905 "Biological and technological aspects of sustainability of controlled ecosystems and their adaptability to climate change".

Comparison of Tissue Heat Balance- and Thermal Dissipation-Derived Sap Flow Measurements in Ring-Porous Oaks and a Pine

PubMed Central

Renninger, Heidi J.; Schäfer, Karina V. R.

2012-01-01

Sap flow measurements have become integral in many physiological and ecological investigations. A number of methods are used to estimate sap flow rates in trees, but probably the most popular is the thermal dissipation (TD) method because of its affordability, relatively low power consumption, and ease of use. However, there have been questions about the use of this method in ring-porous species and whether individual species and site calibrations are needed. We made concurrent measurements of sap flow rates using TD sensors and the tissue heat balance (THB) method in two oak species (Quercus prinus Willd. and Quercus velutina Lam.) and one pine (Pinus echinata Mill.). We also made concurrent measurements of sap flow rates using both 1 and 2-cm long TD sensors in both oak species. We found that both the TD and THB systems tended to match well in the pine individual, but sap flow rates were underestimated by 2-cm long TD sensors in five individuals of the two ring-porous oak species. Underestimations of 20–35% occurred in Q. prinus even when a “Clearwater” correction was applied to account for the shallowness of the sapwood depth relative to the sensor length and flow rates were underestimated by up to 50% in Q. velutina. Two centimeter long TD sensors also underestimated flow rates compared with 1-cm long sensors in Q. prinus, but only at large flow rates. When 2-cm long sensor data in Q. prinus were scaled using the regression with 1-cm long data, daily flow rates matched well with the rates measured by the THB system. Daily plot level transpiration estimated using TD sap flow rates and scaled 1 cm sensor data averaged about 15% lower than those estimated by the THB method. Therefore, these results suggest that 1-cm long sensors are appropriate in species with shallow sapwood, however more corrections may be necessary in ring-porous species. PMID:22661978

Simulating the effect of climate extremes on groundwater flow through a lakebed.

PubMed

Virdi, Makhan L; Lee, Terrie M; Swancar, Amy; Niswonger, Richard G

2013-03-01

Groundwater exchanges with lakes resulting from cyclical wet and dry climate extremes maintain lake levels in the environment in ways that are not well understood, in part because they remain difficult to simulate. To better understand the atypical groundwater interactions with lakes caused by climatic extremes, an original conceptual approach is introduced using MODFLOW-2005 and a kinematic-wave approximation to variably saturated flow that allows lake size and position in the basin to change while accurately representing the daily lake volume and three-dimensional variably saturated groundwater flow responses in the basin. Daily groundwater interactions are simulated for a calibrated lake basin in Florida over a decade that included historic wet and dry departures from the average rainfall. The divergent climate extremes subjected nearly 70% of the maximum lakebed area and 75% of the maximum shoreline perimeter to both groundwater inflow and lake leakage. About half of the lakebed area subject to flow reversals also went dry. A flow-through pattern present for 73% of the decade caused net leakage from the lake 80% of the time. Runoff from the saturated lake margin offset the groundwater deficit only about half of that time. A centripetal flow pattern present for 6% of the decade was important for maintaining the lake stage and generated 30% of all net groundwater inflow. Pumping effects superimposed on dry climate extremes induced the least frequent but most cautionary flow pattern with leakage from over 90% of the actual lakebed area. Published 2012. This article is a U.S. Government work and is in the public domain in the USA.

Spatial distribution of the daily precipitation concentration index in Southern Russia

NASA Astrophysics Data System (ADS)

Vyshkvarkova, Elena; Voskresenskaya, Elena; Martin-Vide, Javier

2018-05-01

The territory of Southern Russia presents a great diversity of climates and complex orography that lead to a very different precipitation distribution. Annual precipitation amounts differ between 222 mm in the coast of the Caspian Sea and > 2000 mm in the highest parts of the Caucasus Mountains. In order to investigate the statistical structure of daily precipitation across the study region the daily precipitation Concentration Index (CI) was used. In present paper, the CI was calculated for 42 meteorological stations during the 1970-2010 period. The analysis of precipitation concentration identified that the distribution of daily precipitation is more regular over the west, north and south regions compared to the east (the Caspian Sea coast and the Caspian Depression). The Crimean peninsula is characterized by low CI values in the north and high values in the eastern part.

Students' daily emotions in the classroom: intra-individual variability and appraisal correlates.

PubMed

Ahmed, Wondimu; van der Werf, Greetje; Minnaert, Alexander; Kuyper, Hans

2010-12-01

Recent literature on emotions in education has shown that competence- and value-related beliefs are important sources of students' emotions; nevertheless, the role of these antecedents in students' daily functioning in the classroom is not yet well-known. More importantly, to date we know little about intra-individual variability in students' daily emotions. The objectives of the study were (1) to examine within-student variability in emotional experiences and (2) to investigate how competence and value appraisals are associated with emotions. It was hypothesized that emotions would show substantial within-student variability and that there would be within-person associations between competence and value appraisals and the emotions. (s) The sample consisted of 120 grade 7 students (52%, girls) in 5 randomly selected classrooms in a secondary school. A diary method was used to acquire daily process variables of emotions and appraisals. Daily emotions and daily appraisals were assessed using items adapted from existing measures. Multi-level modelling was used to test the hypotheses. As predicted, the within-person variability in emotional states accounted for between 41% (for pride) and 70% (for anxiety) of total variability in the emotional states. Also as hypothesized, the appraisals were generally associated with the emotions. The within-student variability in emotions and appraisals clearly demonstrates the adaptability of students with respect to situational affordances and constraints in their everyday classroom experiences. The significant covariations between the appraisals and emotions suggest that within-student variability in emotions is systematic.

Development of a stream-aquifer numerical flow model to assess river water management under water scarcity in a Mediterranean basin.

PubMed

Mas-Pla, Josep; Font, Eva; Astui, Oihane; Menció, Anna; Rodríguez-Florit, Agustí; Folch, Albert; Brusi, David; Pérez-Paricio, Alfredo

2012-12-01

Stream flow, as a part of a basin hydrological cycle, will be sensible to water scarcity as a result of climate change. Stream vulnerability should then be evaluated as a key component of the basin water budget. Numerical flow modeling has been applied to an alluvial formation in a small mountain basin to evaluate the stream-aquifer relationship under these future scenarios. The Arbúcies River basin (116 km(2)) is located in the Catalan Inner Basins (NE Spain) and its lower reach, which is related to an alluvial aquifer, usually becomes dry during the summer period. This study seeks to determine the origin of such discharge losses whether from natural stream leakage and/or induced capture due to groundwater withdrawal. Our goal is also investigating how discharge variations from the basin headwaters, representing potential effects of climate change, may affect stream flow, aquifer recharge, and finally environmental preservation and human supply. A numerical flow model of the alluvial aquifer, based on MODFLOW and especially in the STREAM routine, reproduced the flow system after the usual calibration. Results indicate that, in the average, stream flow provides more than 50% of the water inputs to the alluvial aquifer, being responsible for the amount of stored water resources and for satisfying groundwater exploitation for human needs. Detailed simulations using daily time-steps permit setting threshold values for the stream flow entering at the beginning of the studied area so surface discharge is maintained along the whole watercourse and ecological flow requirements are satisfied as well. The effects of predicted rainfall and temperature variations on the Arbúcies River alluvial aquifer water balance are also discussed from the outcomes of the simulations. Finally, model results indicate the relevance of headwater discharge management under future climate scenarios to preserve downstream hydrological processes. They also point out that small mountain basins could be self-sufficient units so long as the response of the main hydrological components to external forces that produce water scarcity, as climate change or human pressures, is appropriately considered in water resource planning. Copyright © 2012 Elsevier B.V. All rights reserved.

A procedure for calculating daily moisture stress and its utility in regressions of growth and weather

Treesearch

Robert Zahner; Albert R. Stage

1966-01-01

A method is described for computing daily values of moisture stress on forest vegetation, or water deficits, based on the differences between Thornthwaite's potential evapotranspiration and computed soil-moisture depletion. More realistic functions are used for soil-moisture depletion on specific soil types than have been customary. These functions relate daily...

Hydrology of a groundwater-irrigated rice field in Bangladesh: Seasonal and daily mechanisms of infiltration

NASA Astrophysics Data System (ADS)

Neumann, Rebecca B.; Polizzotto, Matthew L.; Badruzzaman, A. Borhan M.; Ali, M. Ashraf; Zhang, Zhongyuan; Harvey, Charles F.

2009-09-01

Flow through a groundwater-irrigated rice field in Bangladesh was characterized with data collected from a transect of tensiometers and time domain reflectometry sensors, novel tracer tests, infiltration tests, soil core analyses, and calculated water budgets. The combined data captured the dynamic hydrologic behavior of the rice field over an entire growing season, which included many irrigation events. Recharge to the aquifer flowed from the surface of the rice field through preferential flow paths located in the subsoil beneath the plowed surface of the field and in the bunds, the raised boundaries around the perimeter of the field. Water that remained within the soil matrix did not recharge the aquifer. Bund flow was the dominant loss for the field because the bulk hydraulic conductivity of the soil beneath the bunds was greater than that in the plowed and planted region of the rice field. Each year, farmers plow the rice fields, destroying cracks and decreasing the conductivity of the shallow soil, but leave the bunds unplowed because they follow property boundaries. We determined bund flow with a daily water balance and confirmed its importance by comparing irrigation losses among fields of different sizes and geometries and hence different ratios of perimeter to area. The perimeter-to-area ratio predicted the fraction of water lost down the bunds for these and other fields located throughout Southeast Asia. Finally, we determined the economic and environmental benefits of reducing bund flow.

A statistical method to predict flow permanence in dryland streams from time series of stream temperature

USGS Publications Warehouse

Arismendi, Ivan; Dunham, Jason B.; Heck, Michael; Schultz, Luke; Hockman-Wert, David

2017-01-01

Intermittent and ephemeral streams represent more than half of the length of the global river network. Dryland freshwater ecosystems are especially vulnerable to changes in human-related water uses as well as shifts in terrestrial climates. Yet, the description and quantification of patterns of flow permanence in these systems is challenging mostly due to difficulties in instrumentation. Here, we took advantage of existing stream temperature datasets in dryland streams in the northwest Great Basin desert, USA, to extract critical information on climate-sensitive patterns of flow permanence. We used a signal detection technique, Hidden Markov Models (HMMs), to extract information from daily time series of stream temperature to diagnose patterns of stream drying. Specifically, we applied HMMs to time series of daily standard deviation (SD) of stream temperature (i.e., dry stream channels typically display highly variable daily temperature records compared to wet stream channels) between April and August (2015–2016). We used information from paired stream and air temperature data loggers as well as co-located stream temperature data loggers with electrical resistors as confirmatory sources of the timing of stream drying. We expanded our approach to an entire stream network to illustrate the utility of the method to detect patterns of flow permanence over a broader spatial extent. We successfully identified and separated signals characteristic of wet and dry stream conditions and their shifts over time. Most of our study sites within the entire stream network exhibited a single state over the entire season (80%), but a portion of them showed one or more shifts among states (17%). We provide recommendations to use this approach based on a series of simple steps. Our findings illustrate a successful method that can be used to rigorously quantify flow permanence regimes in streams using existing records of stream temperature.

Effects of rainfall patterns and land cover on the subsurface flow generation of sloping Ferralsols in southern China

PubMed Central

Yang, Jie; Tang, Chongjun; Chen, Lihua; Liu, Yaojun; Wang, Lingyun

2017-01-01

Rainfall patterns and land cover are two important factors that affect the runoff generation process. To determine the surface and subsurface flows associated with different rainfall patterns on sloping Ferralsols under different land cover types, observational data related to surface and subsurface flows from 5 m × 15 m plots were collected from 2010 to 2012. The experiment was conducted to assess three land cover types (grass, litter cover and bare land) in the Jiangxi Provincial Soil and Water Conservation Ecological Park. During the study period, 114 natural rainfall events produced subsurface flow and were divided into four groups using k-means clustering according to rainfall duration, rainfall depth and maximum 30-min rainfall intensity. The results showed that the total runoff and surface flow values were highest for bare land under all four rainfall patterns and lowest for the covered plots. However, covered plots generated higher subsurface flow values than bare land. Moreover, the surface and subsurface flows associated with the three land cover types differed significantly under different rainfall patterns. Rainfall patterns with low intensities and long durations created more subsurface flow in the grass and litter cover types, whereas rainfall patterns with high intensities and short durations resulted in greater surface flow over bare land. Rainfall pattern I had the highest surface and subsurface flow values for the grass cover and litter cover types. The highest surface flow value and lowest subsurface flow value for bare land occurred under rainfall pattern IV. Rainfall pattern II generated the highest subsurface flow value for bare land. Therefore, grass or litter cover are able to convert more surface flow into subsurface flow under different rainfall patterns. The rainfall patterns studied had greater effects on subsurface flow than on total runoff and surface flow for covered surfaces, as well as a greater effect on surface flows associated with bare land. PMID:28792507

Uncertainty in low-flow data from three streamflow-gaging stations on the upper Verde River, Arizona

USGS Publications Warehouse

Anning, D.W.; ,

2004-01-01

The evaluation of uncertainty in low-flow data collected from three streamflow-gaging stations on the upper Verde River, Arizona, was presented. In downstream order, the stations are Verde River near Paulden, Verde River near Clarkdale, and Verde River near Camp Verde. A monitoring objective of the evaluation was to characterize discharge of the lower flow regime through a variety of procedures such as frequency analysis and base-flow analysis. For Verde River near Paulden and near Camp Verde, the uncertainty of daily low flows can be reduced by decreasing the uncertainty of discharge-measurement frequency, or building an artificial control that would have a stable stage-discharge relation over time.

Nutrient contributions and biogas potential of co-digestion of feedstocks and dairy manure.

PubMed

Ma, Guiling; Neibergs, J Shannon; Harrison, Joseph H; Whitefield, Elizabeth M

2017-06-01

This study focused on collection of data on nutrient flow and biogas yield at a commercial anaerobic digester managed with dairy manure from a 1000 cow dairy and co-digestion of additional feedstocks. Feedstocks included: blood, fish, paper pulp, out of date beverages and grease trap waste. Mass flow of inputs and outputs, nutrient concentration of inputs and outputs, and biogas yield were obtained. It was determined that manure was the primary source of nutrients to the anaerobic digester when co-digested with feedstocks. The percentage of contribution from manure to the total nutrient inputs for total nitrogen, ammonia-nitrogen, phosphorus and total solids was 46.3%, 67.7%, 32.8% and 23.4%, respectively. On average, manure contributed the greatest amount of total nitrogen and ammonia-nitrogen. Grease trap waste contributed the greatest amount of phosphorus and total solids at approximately 50%. Results demonstrated that a reliable estimate of nutrient inflow could be obtained from the product of the nutrient analyses of a single daily composite of influent subsamples times the total daily flow estimated with an in-line flow meter. This approach to estimate total daily nutrient inflow would be more cost effective than testing and summing the contribution of individual feedstocks. Data collected after liquid-solid separation confirmed that the majority (>75%) of nutrients remain with the liquid effluent portion of the manure stream. It was demonstrated that the ash concentration in solids before and after composting could be used to estimate the mass balance of total solids during the compost process. This data confirms that biogas or methane yield could be accurately measured from the ratio of % volatile solids to % total solids. Copyright © 2017 Elsevier Ltd. All rights reserved.

On the relationship between the tree and its environment, based on electrical potential difference monitoring on trunk of trees

NASA Astrophysics Data System (ADS)

Koppan, A.; Fenyvesi, A.; Szarka, L.; Wesztergom, V.

2002-05-01

Electrical potential differences (EPD) in the trunk of a Turkey oak tree (measured by using non-polarising electrodes deepened in the sap wood) have been continuously recorded in the Geophysical Observatory "Istv n Széchenyi" of the Hungarian Academy of Sciences since 1997. Besides of various geophysical observations, meteorological and direct sap-flow measurements have also been carried out in the observatory. As it was found (Kopp n A., Szarka L., Wesztergom V., 2000: Annual fluctuation in amplitudes of daily variations of electrical signals measured in the trunk of a standing tree. C.R. Acad. Sci. Paris, Life Sciences 323, 559-563), the measured electric potential difference data have a characteristic sinusoidal daily fluctuation, and the intensity of the diurnal variations has a double-peak annual characteristics, which coincides with the life activity maximums of the tree. We have found a remarkable inter-correlation between trunk EPD, water potential of air (derived from meteorological data), and direct sap flow velocity data from a neighboring tree. All these results clearly demonstrate that the sap streaming due to the transpiration and root pressure generates the largest part of measured potential differences. The ratio of the flow velocity of a diluted solution forced through stems and the potential differences was found to be constant (Gindl, W., L”ppert, H.-G., Wimmer, R., 1999: Relationship between streaming potential and sap velocity in Salix alba L. Phyton, 39, 217-224.). On the contrary in our in-vivo experiments the relationship between the measured sap flow velocity and EPD is non-linear, which means that the conductivity (i.e. ion concentration) of the xylem sap itself also has a daily fluctuation.

Use of continuous and grab sample data for calculating total maximum daily load (TMDL) in agricultural watersheds.

PubMed

Gulati, Shelly; Stubblefield, Ashley A; Hanlon, Jeremy S; Spier, Chelsea L; Stringfellow, William T

2014-03-01

Measuring the discharge of diffuse pollution from agricultural watersheds presents unique challenges. Flows in agricultural watersheds, particularly in Mediterranean climates, can be predominately irrigation runoff and exhibit large diurnal fluctuation in both volume and concentration. Flow and pollutant concentrations in these smaller watersheds dominated by human activity do not conform to a normal distribution and it is not clear if parametric methods are appropriate or accurate for load calculations. The objective of this study was to compare the accuracy of five load estimation methods to calculate pollutant loads from agricultural watersheds. Calculation of loads using results from discrete (grab) samples was compared with the true-load computed using in situ continuous monitoring measurements. A new method is introduced that uses a non-parametric measure of central tendency (the median) to calculate loads (median-load). The median-load method was compared to more commonly used parametric estimation methods which rely on using the mean as a measure of central tendency (mean-load and daily-load), a method that utilizes the total flow volume (volume-load), and a method that uses measure of flow at the time of sampling (instantaneous-load). Using measurements from ten watersheds in the San Joaquin Valley of California, the average percent error compared to the true-load for total dissolved solids (TDS) was 7.3% for the median-load, 6.9% for the mean-load, 6.9% for the volume-load, 16.9% for the instantaneous-load, and 18.7% for the daily-load methods of calculation. The results of this study show that parametric methods are surprisingly accurate, even for data that have starkly non-normal distributions and are highly skewed. Copyright © 2013 Elsevier Ltd. All rights reserved.

Evaluating the spatial distribution of water balance in a small watershed, Pennsylvania

NASA Astrophysics Data System (ADS)

Yu, Zhongbo; Gburek, W. J.; Schwartz, F. W.

2000-04-01

A conceptual water-balance model was modified from a point application to be distributed for evaluating the spatial distribution of watershed water balance based on daily precipitation, temperature and other hydrological parameters. The model was calibrated by comparing simulated daily variation in soil moisture with field observed data and results of another model that simulates the vertical soil moisture flow by numerically solving Richards' equation. The impacts of soil and land use on the hydrological components of the water balance, such as evapotranspiration, soil moisture deficit, runoff and subsurface drainage, were evaluated with the calibrated model in this study. Given the same meteorological conditions and land use, the soil moisture deficit, evapotranspiration and surface runoff increase, and subsurface drainage decreases, as the available water capacity of soil increases. Among various land uses, alfalfa produced high soil moisture deficit and evapotranspiration and lower surface runoff and subsurface drainage, whereas soybeans produced an opposite trend. The simulated distribution of various hydrological components shows the combined effect of soil and land use. Simulated hydrological components compare well with observed data. The study demonstrated that the distributed water balance approach is efficient and has advantages over the use of single average value of hydrological variables and the application at a single point in the traditional practice.

Mixing the Green-Ampt model and Curve Number method as an empirical tool for rainfall excess estimation in small ungauged catchments.

NASA Astrophysics Data System (ADS)

Grimaldi, S.; Petroselli, A.; Romano, N.

2012-04-01

The Soil Conservation Service - Curve Number (SCS-CN) method is a popular rainfall-runoff model that is widely used to estimate direct runoff from small and ungauged basins. The SCS-CN is a simple and valuable approach to estimate the total stream-flow volume generated by a storm rainfall, but it was developed to be used with daily rainfall data. To overcome this drawback, we propose to include the Green-Ampt (GA) infiltration model into a mixed procedure, which is referred to as CN4GA (Curve Number for Green-Ampt), aiming to distribute in time the information provided by the SCS-CN method so as to provide estimation of sub-daily incremental rainfall excess. For a given storm, the computed SCS-CN total net rainfall amount is used to calibrate the soil hydraulic conductivity parameter of the Green-Ampt model. The proposed procedure was evaluated by analyzing 100 rainfall-runoff events observed in four small catchments of varying size. CN4GA appears an encouraging tool for predicting the net rainfall peak and duration values and has shown, at least for the test cases considered in this study, a better agreement with observed hydrographs than that of the classic SCS-CN method.

Accumulated exposure to ozone and measurement of health effects in children and counselors at two summer camps

DOE Office of Scientific and Technical Information (OSTI.GOV)

Berry, M.; Lioy, P.J.; Gelperin, K.

1991-04-01

In the summer of 1988 a multiorganizational field health study was conducted at two summer day camps in suburban-central New Jersey. Thirty-four campers and counselors had daily pulmonary function tests performed each afternoon while attending camp during the month of July. The subjects ranged from 9 to 35 years of age. A mobile medical screening van was used to house the spirometric equipment and travel to each camp. Continuous ozone measurements were collected over the 19-test day study period. An intense ozone episode was recorded just prior to and during the first 2 weeks of the study. The campers hadmore » an increase in respiratory symptoms with increases in ozone concentrations above 120 ppb. Exposures below 120 ppb ozone were not significantly associated with symptoms. Peak expiratory flow rate in children was the only lung function measure associated with increasing ozone concentrations, with an average loss of 4.74 ml/sec/ppb (P-value = 0.05) for the 8-hr ozone exposure measure. Furthermore, it appears that the early intense exposure to ozone produced a persistent decrease in lung function and baseline shift for three days after the episode that obscured the daily dose-response relationship.« less

Sensitivity of Daily Doses of Biologically Active Radiation, To Ozone Changes In Southern French Alps

NASA Astrophysics Data System (ADS)

de La Casinière, A.; Touré, M. L.; Masserot, D.; Lenoble, J.; Cabot, T.; Pinedo Vega, J. L.

Global UV irradiance spectra we re recorded each half an hour between sunrise and sunset, along the year 2000 in Briançon (1300m asl) at the CEMBREU (Centre Européen Médical Bioclimatique de Recherche et d'Enseignement Universitaire), a site of the French spectral UV network in Southern Alps. From these spectra are retrieved atmospheric transmissivities corresponding to daily doses of various biologically active radiation. A transmissivity is defined as the ratio of the ground level value of a daily dose to the extra -atmospheric value of this daily dose. The daily doses studied relate to UVB, erythema, DNA damage, and plant damage. Multiple linear correlations of the various transmissivities with the three predictors (daily sunshine fraction), µmin (cosine of the daily minimum SZA), and (daily total ozone column) assumed to be independent variables, are done for year 2000. These correlations permit to assess the mean sensitivities of the various transmissivities, to changes in for different cloud cover conditions in Briançon. The variations of each sensitivity is studied as a function of , µmin and . Comparing the results obtained with those given in the literature, we find for = 1 (that is for a strong probability of clear sky conditions) and SZA min = 45°, a radiation amplification factor (RAF) of the erythemal daily dose equal to 1.1 when = 285 DU, and to 1.4 when = 315 DU.

Watershed model calibration framework developed using an influence coefficient algorithm and a genetic algorithm and analysis of pollutant discharge characteristics and load reduction in a TMDL planning area.

PubMed

Cho, Jae Heon; Lee, Jong Ho

2015-11-01

Manual calibration is common in rainfall-runoff model applications. However, rainfall-runoff models include several complicated parameters; thus, significant time and effort are required to manually calibrate the parameters individually and repeatedly. Automatic calibration has relative merit regarding time efficiency and objectivity but shortcomings regarding understanding indigenous processes in the basin. In this study, a watershed model calibration framework was developed using an influence coefficient algorithm and genetic algorithm (WMCIG) to automatically calibrate the distributed models. The optimization problem used to minimize the sum of squares of the normalized residuals of the observed and predicted values was solved using a genetic algorithm (GA). The final model parameters were determined from the iteration with the smallest sum of squares of the normalized residuals of all iterations. The WMCIG was applied to a Gomakwoncheon watershed located in an area that presents a total maximum daily load (TMDL) in Korea. The proportion of urbanized area in this watershed is low, and the diffuse pollution loads of nutrients such as phosphorus are greater than the point-source pollution loads because of the concentration of rainfall that occurs during the summer. The pollution discharges from the watershed were estimated for each land-use type, and the seasonal variations of the pollution loads were analyzed. Consecutive flow measurement gauges have not been installed in this area, and it is difficult to survey the flow and water quality in this area during the frequent heavy rainfall that occurs during the wet season. The Hydrological Simulation Program-Fortran (HSPF) model was used to calculate the runoff flow and water quality in this basin. Using the water quality results, a load duration curve was constructed for the basin, the exceedance frequency of the water quality standard was calculated for each hydrologic condition class, and the percent reduction required to achieve the water quality standard was estimated. The R(2) value for the calibrated BOD5 was 0.60, which is a moderate result, and the R(2) value for the TP was 0.86, which is a good result. The percent differences obtained for the calibrated BOD5 and TP were very good; therefore, the calibration results using WMCIG were satisfactory. From the load duration curve analysis, the WQS exceedance frequencies of the BOD5 under dry conditions and low-flow conditions were 75.7% and 65%, respectively, and the exceedance frequencies under moist and mid-range conditions were higher than under other conditions. The exceedance frequencies of the TP for the high-flow, moist and mid-range conditions were high and the exceedance rate for the high-flow condition was particularly high. Most of the data from the high-flow conditions exceeded the WQSs. Thus, nonpoint-source pollutants from storm-water runoff substantially affected the TP concentration in the Gomakwoncheon. Copyright © 2015 Elsevier Ltd. All rights reserved.

Concentrations and transport of atrazine in the Delaware River-Perry Lake system, northeast Kansas, July 1993 through September 1995

USGS Publications Warehouse

Pope, L.M.; Brewer, L.D.; Foley, G.A.; Morgan, S.C.

1996-01-01

A study of the distribution and transport of atrazine in surface water in the 1,117 square-mile Delaware River Basin in northeast Kansas was conducted from July 1992 through September 1995. The purpose of this report is to present information to assess the present (1992-95) conditions and possible future changes in the distribution and magnitude of atrazine concentrations, loads, and yields spatially, temporally, and in relation to hydrologic conditions and land-use characteristics. A network of 11 stream-monitoring and sample-collection sites was established within the basin. Stream- water samples were collected during a wide range of hydrologic conditions throughout the study. Nearly 5,000 samples were analyzed by enzyme- linked immunosorbent assay (ELISA) for triazine herbicide concentrations. Daily mean triazine herbicide concentrations were calculated for all sampling sites and subsequently used to estimate daily mean atrazine concentrations with a linear- regression relation between ELISA-derived triazine concentrations and atrazine concentrations determined by gas chromatography/mass spectrometry for 141 dual-analyzed surface-water samples. During May, June, and July, time-weighted, daily mean atrazine concentrations in streams in the Delaware River Basin commonly exceeded the value of 3.0-ug/L (micrograms per liter) annual mean Maximum Contaminant Level (MCL) established by the U.S. Environmental Protection Agency for drinking-water supplies. Time-weighted, daily mean concentrations equal to or greater than 20 ug/L were not uncommon. However, most time- weighted, daily mean concentrations were less than 1.0 ug/L from August through April. The largest time-weighted, monthly mean atrazine concentrations occurred during May, June, and July. Most monthly mean concentrations between August and April were less than 0.50 ug/L. Large differences were documented in monthly mean concentrations within the basin. Sites receiving runoff from the northern and northeastern parts of the Delaware River Basin had the largest monthly and annual mean atrazine concentrations. Time- weighted, annual mean atrazine concentrations did not exceed the MCL in water from any sampling site for either the 1993 or 1994 crop years (April-March); however, concentrations were during 1994 than during 1993. Time-weighted, annual mean concentrations in water from among the 11 sampling sites during the 1993 crop year ranged from 0.27 to 1.5 ug/L and from 0.36 to 2.8 ug/L during the 1994 crop year. Furthermore, concentrations in samples from the outflow of Perry Lake were larger during the first 6 months of the 1995 crop year than during the previous year. Flow-weighted, annual mean atrazine concentrations were larger than time-weighted, annual mean concentrations in water from all sampling sites upstream of Perry Lake, and samples from several sites had concentrations were substantially larger than the MCL. This difference explained why time-weighted, annual mean concentrations in the outflow of Perry Lake were larger than corresponding time-weighted concentrations in water from sampling sites upstream of Perry Lake. Flow- weighted, annual mean concentrations in water from among the 11 sampling sites during the 1993 crop year ranged from 1.0 to 4.4 ug/L and from 1.0 to 8.9 ug/L during the 1994 crop year. Statistically significant linear-regression equations were identified relating the percentage of subbasin in cropland to time- and flow-weighted, average annual mean atrazine concentrations. The relations indicate that time-weighted, average annual mean atrazine concentrations may not exceed the MCL in water from subbasins with at least about 70-percent cropland. However, flow-weighted, average annual mean atrazine concentrations may exceed the MCL when the percentage of cropland is greater than about 40 percent. Approximately 90 percent of the annual atrazine load is transport from May through July. Atrazine loads and yields were larger during the 1993 cro

Impact of blood flow on diffusion coefficients of the human kidney: a time-resolved ECG-triggered diffusion-tensor imaging (DTI) study at 3T.

PubMed

Heusch, Philipp; Wittsack, Hans-Jörg; Kröpil, Patric; Blondin, Dirk; Quentin, Michael; Klasen, Janina; Pentang, Gael; Antoch, Gerald; Lanzman, Rotem S

2013-01-01

To evaluate the impact of renal blood flow on apparent diffusion coefficients (ADC) and fractional anisotropy (FA) using time-resolved electrocardiogram (ECG)-triggered diffusion-tensor imaging (DTI) of the human kidneys. DTI was performed in eight healthy volunteers (mean age 29.1 ± 3.2) using a single slice coronal echoplanar imaging (EPI) sequence (3 b-values: 0, 50, and 300 s/mm(2)) at the timepoint of minimum (20 msec after R wave) and maximum renal blood flow (200 msec after R wave) at 3T. Following 2D motion correction, region of interest (ROI)-based analysis of cortical and medullary ADC- and FA-values was performed. ADC-values of the renal cortex at maximum blood flow (2.6 ± 0.19 × 10(-3) mm(2)/s) were significantly higher than at minimum blood flow (2.2 ± 0.11 × 10(-3) mm(2)/s) (P < 0.001), while medullary ADC-values did not differ significantly (maximum blood flow: 2.2 ± 0.18 × 10(-3) mm(2)/s; minimum blood flow: 2.15 ± 0.14 × 10(-3) mm(2)/s). FA-values of the renal medulla were significantly greater at maximal blood (0.53 ± 0.05) than at minimal blood flow (0.47 ± 0.05) (P < 0.01). In contrast, cortical FA-values were comparable at different timepoints of the cardiac cycle. ADC-values in the renal cortex as well as FA-values in the renal medulla are influenced by renal blood flow. This impact has to be considered when interpreting renal ADC- and FA-values. Copyright © 2012 Wiley Periodicals, Inc.

The influence of broiler activity, growth rate, and litter on carbon dioxide balances for the determination of ventilation flow rates in broiler production.

PubMed

Calvet, S; Estellés, F; Cambra-López, M; Torres, A G; Van den Weghe, H F A

2011-11-01

Carbon dioxide balances are useful in determining ventilation rates in livestock buildings. These balances need an accurate estimation of the CO(2) produced by animals and their litter to determine the ventilation flows. To estimate the daily variation in ventilation flow, it is necessary to precisely know the daily variation pattern of CO(2) production, which mainly depends on animal activity. The objective of this study was to explore the applicability of CO(2) balances for determining ventilation flows in broiler buildings. More specifically, this work aimed to quantify the amount of CO(2) produced by the litter, as well as the amount of CO(2) produced by the broilers, as a function of productive parameters, and to analyze the influence of broiler activity on CO(2) emissions. Gas concentrations and ventilation flows were simultaneously measured in 3 trials, with 1 under experimental conditions and the other 2 in a commercial broiler farm. In the experimental assay, broiler activity was also determined. At the end of the experimental trial, on the day after the removal of the broilers, the litter accounted for 20% of the total CO(2) produced, and the broilers produced 3.71 L/h of CO(2) per kg of metabolic weight. On the commercial farm, CO(2) production was the same for the 2 cycles (2.60 L/h per kg of metabolic weight, P > 0.05). However, substantial differences were found between CO(2) and broiler activity patterns after changes in light status. A regression model was used to explain these differences (R(2) = 0.52). Carbon dioxide increased with bird activity, being on average 3.02 L/h per kg of metabolic weight for inactive birds and 4.73 L/h per kg of metabolic weight when bird activity was highest. Overall, CO(2) balances are robust tools for determining the daily average ventilation flows in broiler farms. These balances could also be applied at more frequent intervals, but in this case, particular care is necessary after light status changes because of discrepancy between animal activity and CO(2) production.

Estimates of Flow Duration, Mean Flow, and Peak-Discharge Frequency Values for Kansas Stream Locations

USGS Publications Warehouse

Perry, Charles A.; Wolock, David M.; Artman, Joshua C.

2004-01-01

Streamflow statistics of flow duration and peak-discharge frequency were estimated for 4,771 individual locations on streams listed on the 1999 Kansas Surface Water Register. These statistics included the flow-duration values of 90, 75, 50, 25, and 10 percent, as well as the mean flow value. Peak-discharge frequency values were estimated for the 2-, 5-, 10-, 25-, 50-, and 100-year floods. Least-squares multiple regression techniques were used, along with Tobit analyses, to develop equations for estimating flow-duration values of 90, 75, 50, 25, and 10 percent and the mean flow for uncontrolled flow stream locations. The contributing-drainage areas of 149 U.S. Geological Survey streamflow-gaging stations in Kansas and parts of surrounding States that had flow uncontrolled by Federal reservoirs and used in the regression analyses ranged from 2.06 to 12,004 square miles. Logarithmic transformations of climatic and basin data were performed to yield the best linear relation for developing equations to compute flow durations and mean flow. In the regression analyses, the significant climatic and basin characteristics, in order of importance, were contributing-drainage area, mean annual precipitation, mean basin permeability, and mean basin slope. The analyses yielded a model standard error of prediction range of 0.43 logarithmic units for the 90-percent duration analysis to 0.15 logarithmic units for the 10-percent duration analysis. The model standard error of prediction was 0.14 logarithmic units for the mean flow. Regression equations used to estimate peak-discharge frequency values were obtained from a previous report, and estimates for the 2-, 5-, 10-, 25-, 50-, and 100-year floods were determined for this report. The regression equations and an interpolation procedure were used to compute flow durations, mean flow, and estimates of peak-discharge frequency for locations along uncontrolled flow streams on the 1999 Kansas Surface Water Register. Flow durations, mean flow, and peak-discharge frequency values determined at available gaging stations were used to interpolate the regression-estimated flows for the stream locations where available. Streamflow statistics for locations that had uncontrolled flow were interpolated using data from gaging stations weighted according to the drainage area and the bias between the regression-estimated and gaged flow information. On controlled reaches of Kansas streams, the streamflow statistics were interpolated between gaging stations using only gaged data weighted by drainage area.

Multi-model ensemble hydrologic prediction using Bayesian model averaging

NASA Astrophysics Data System (ADS)

Duan, Qingyun; Ajami, Newsha K.; Gao, Xiaogang; Sorooshian, Soroosh

2007-05-01

Multi-model ensemble strategy is a means to exploit the diversity of skillful predictions from different models. This paper studies the use of Bayesian model averaging (BMA) scheme to develop more skillful and reliable probabilistic hydrologic predictions from multiple competing predictions made by several hydrologic models. BMA is a statistical procedure that infers consensus predictions by weighing individual predictions based on their probabilistic likelihood measures, with the better performing predictions receiving higher weights than the worse performing ones. Furthermore, BMA provides a more reliable description of the total predictive uncertainty than the original ensemble, leading to a sharper and better calibrated probability density function (PDF) for the probabilistic predictions. In this study, a nine-member ensemble of hydrologic predictions was used to test and evaluate the BMA scheme. This ensemble was generated by calibrating three different hydrologic models using three distinct objective functions. These objective functions were chosen in a way that forces the models to capture certain aspects of the hydrograph well (e.g., peaks, mid-flows and low flows). Two sets of numerical experiments were carried out on three test basins in the US to explore the best way of using the BMA scheme. In the first set, a single set of BMA weights was computed to obtain BMA predictions, while the second set employed multiple sets of weights, with distinct sets corresponding to different flow intervals. In both sets, the streamflow values were transformed using Box-Cox transformation to ensure that the probability distribution of the prediction errors is approximately Gaussian. A split sample approach was used to obtain and validate the BMA predictions. The test results showed that BMA scheme has the advantage of generating more skillful and equally reliable probabilistic predictions than original ensemble. The performance of the expected BMA predictions in terms of daily root mean square error (DRMS) and daily absolute mean error (DABS) is generally superior to that of the best individual predictions. Furthermore, the BMA predictions employing multiple sets of weights are generally better than those using single set of weights.

Hydrochemical processes in lowland rivers: insights from in situ, high-resolution monitoring

NASA Astrophysics Data System (ADS)

Wade, A. J.; Palmer-Felgate, E. J.; Halliday, S. J.; Skeffington, R. A.; Loewenthal, M.; Jarvie, H. P.; Bowes, M. J.; Greenway, G. M.; Haswell, S. J.; Bell, I. M.; Joly, E.; Fallatah, A.; Neal, C.; Williams, R. J.; Gozzard, E.; Newman, J. R.

2012-11-01

This paper introduces new insights into the hydrochemical functioning of lowland river systems using field-based spectrophotometric and electrode technologies. The streamwater concentrations of nitrogen species and phosphorus fractions were measured at hourly intervals on a continuous basis at two contrasting sites on tributaries of the River Thames - one draining a rural catchment, the River Enborne, and one draining a more urban system, The Cut. The measurements complement those from an existing network of multi-parameter water quality sondes maintained across the Thames catchment and weekly monitoring based on grab samples. The results of the sub-daily monitoring show that streamwater phosphorus concentrations display highly complex dynamics under storm conditions dependent on the antecedent catchment wetness, and that diurnal phosphorus and nitrogen cycles occur under low flow conditions. The diurnal patterns highlight the dominance of sewage inputs in controlling the streamwater phosphorus and nitrogen concentrations at low flows, even at a distance of 7 km from the nearest sewage treatment works in the rural River Enborne. The time of sample collection is important when judging water quality against ecological thresholds or standards. An exhaustion of the supply of phosphorus from diffuse and multiple septic tank sources during storm events was evident and load estimation was not improved by sub-daily monitoring beyond that achieved by daily sampling because of the eventual reduction in the phosphorus mass entering the stream during events. The results highlight the utility of sub-daily water quality measurements and the discussion considers the practicalities and challenges of in situ, sub-daily monitoring.

Probable effects of the proposed Sulphur Gulch Reservoir on Colorado River quantity and quality near Grand Junction, Colorado

USGS Publications Warehouse

Friedel, M.J.

2004-01-01

A 16,000 acre-foot reservoir is proposed to be located about 25 miles east of Grand Junction, Colorado, on a tributary of the Colorado River that drains the Sulphur Gulch watershed between De Beque and Cameo, Colorado. The Sulphur Gulch Reservoir, which would be filled by pumping water from the Colorado River, is intended to provide the Colorado River with at least 5,412.5 acre-feet of water during low-flow conditions to meet the East Slopes portion of the 10,825 acre-feet of water required under the December 20, 1999, Final Programmatic Biological Opinion for the Upper Colorado River. The reservoir also may provide additional water in the low-flow period and as much as 10,000 acre-feet of water to supplement peak flows when flows in the Colorado River are between 12,900 and 26,600 cubic feet per second. For this study, an annual stochastic mixing model with a daily time step and 1,500 Monte Carlo trials were used to evaluate the probable effect that reservoir operations may have on water quality in the Colorado River at the Government Highline Canal and the Grand Valley Irrigation Canal. Simulations of the divertible flow (ambient background streamflow), after taking into account demands of downstream water rights, indicate that divertible flow will range from 621,860 acre-feet of water in the driest year to 4,822,732 acrefeet of water in the wettest year. Because of pumping limitations, pumpable flow (amount of streamflow available after considering divertible flow and subsequent pumping constraints) will be less than divertible flow. Assuming a pumping capacity of 150 cubic feet per second and year round pumping, except during reservoir release periods, the simulations indicate that there is sufficient streamflow to fill a 16,000 acre-feet reservoir 100 percent of the time. Simulated pumpable flows in the driest year are 91,669 acre-feet and 109,500 acre-feet in the wettest year. Simulations of carryover storage together with year-round pumping indicate that there is generally sufficient pumpable flow available to refill the reservoir to capacity each year following peak-flow releases of as much as 10,000 acrefeet and low-flow releases of 5,412.5 acre-feet of water. It is assumed that at least 5,412.5 acre-feet of stored water will be released during low-flow conditions irrespective of the hydrologic condition. Simulations indicate that peak-flow release conditions (flows between 12,900 and 26,600 cubic feet per second) to allow release of 10,000 acre-feet of stored water in the spring will occur only about 50 percent of the time. Under typical (5 of 10 years) to moderately dry (3 of 10 years) hydrologic conditions, the duration of the peak-flow conditions will not allow the full 10,000 acre-feet to be released from storage to supplement peak flows. During moderate to extremely dry (2 of 10 years) hydrologic conditions, the peak-flow release conditions will not occur, and there will be no opportunity to release water from storage to supplement peak flows. In general, the simulated daily background dissolved-solids concentrations (salinity) increase due to the reservoir releases as hydrologic conditions go from wet to dry at the Government Highline Canal. For example, the simulated median concentrations during the low-flow period range from 417 milligrams per liter (wet year) to 723 milligrams per liter (dry year), whereas the simulated median concentrations observed during the peak-flow period range from 114 milligrams per liter (wet year) to 698 milligrams per liter (dry year). Background concentration values at the Grand Valley Irrigation Canal are generally only a few percent less than those at the Government Highline Canal except during dry years. Low-flow reservoir releases of 5,412.5 acre-feet and 10,825 acre-feet were simulated for a 30-day period in September, and low-flow releases of 5,412.5 acre-feet were simulated for a 78-day period in the months of August through October. In general, these low-flo

[Comparison of eddy covariance and static chamber/gas chromatogram methods in measuring ecosystem respiration].

PubMed

Zheng, Ze-Mei; Yu, Gui-Rui; Sun, Xiao-Min; Cao, Guang-Min; Wang, Yue-Si; Du, Ming-Yuan; Li, Jun; Li, Ying-Nian

2008-02-01

Based on the measurement of carbon flux by the methods of eddy covariance and static chamber/gas chromatogram, a comparison was made between the two methods in evaluating ecosystem respiration over winter wheat (Triticum aestivum)--summer maize (Zea mays) double cropland and Kobresia humilis alpine meadow. The results showed that under the conditions of obtained data having good quality, nighttime ecosystem respiration from eddy covariance measurement was significantly agreed with that from static chamber/gas chromatogram measurement, with the correlation coefficients ranging from 0.95 to 0.98, and the daytime ecosystem respiration from these two measurements also had a good consistency though the static chamber/gas chromatogram measurement often produced higher values. The daily mean value of ecosystem respiration was significantly different between these two measurements, but the seasonal pattern was similar. For winter wheat-summer maize double cropland, the difference of mean air temperature inside and outside the chamber was 1.8 degrees C, and the daily mean value of ecosystem respiration across the whole study period was 30.3% lower in eddy covariance measurement than in static chamber/gas chromatogram measurement; while for alpine meadow, the difference of the mean air temperature was 1.9 degrees C, and the daily mean value of ecosystem respiration was 31.4% lower in eddy covariance measurement than in static chamber/gas chromatogram measurement. The variance between the daily mean values of ecosystem respiration obtained from the two measurements was higher in growing season than in dormant season.

Associations between women's subjective perceptions of daily occupations and life satisfaction, and the role of perceived control.

PubMed

Håkansson, Carita; Björkelund, Cecilia; Eklund, Mona

2011-12-01

More knowledge is needed about the role of perceived control in the associations between different perceptions of daily occupations and positive health outcomes. The aim was to explore the associations between different subjective perceptions of daily occupations, in terms of occupational balance, occupational meaning, occupational value and satisfaction with occupations, and life satisfaction, and the role of perceived control in those associations. A questionnaire including questions about perceptions of daily occupations, perceived control and life satisfaction were answered by a random sample of 488 middle-aged Swedish women. Multiple logistic regression analysis was used to test the associations between perceptions of daily occupations and life satisfaction, and the role of perceived control. After adjustments for perceived control women who perceived a high level of satisfaction with work and leisure, occupational balance, occupational meaning and occupational value perceived greater life satisfaction than the other women. Perceived control was not significant in the model. It seems that occupational balance and occupational meaning were pivotal for the women's life satisfaction, but satisfaction with work and leisure, as well as perceived occupational value, was also of importance. The assumption that perceived control would have a role in the association between perceptions of occupations and life satisfaction was not confirmed. The results indicate that occupational therapists need to focus on occupational balance, occupational meaning, occupational value and satisfaction with work and leisure to promote positive health outcomes, in terms of life satisfaction, when working with middle-aged female clients. © 2011 The Authors. Australian Occupational Therapy Journal © 2011 Occupational Therapy Australia.

Fuel cell and membrane therefore

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aindow, Tai-Tsui

A fuel cell includes first and second flow field plates, and an anode electrode and a cathode electrode between the flow field plates. A polymer electrolyte membrane (PEM) is arranged between the electrodes. At least one of the flow field plates influences, at least in part, an in-plane anisotropic physical condition of the PEM that varies in magnitude between a high value direction and a low value direction. The PEM has an in-plane physical property that varies in magnitude between a high value direction and a low value direction. The PEM is oriented with its high value direction substantially alignedmore » with the high value direction of the flow field plate.« less

Copper and zinc level in biological samples from healthy subjects of vegetarian food habit in reference to community environment.

PubMed

Bhattacharya, R D; Patel, T S; Pandya, C B

1985-01-01

Many epidemiologists have found a correlation between copper and zinc in the community environment and diseases, such as myocardial and vascular pathologies, and diabetes. The purpose of this study was to investigate the total daily intake of these two metals in cooked food, drinking water and air and their respective levels in blood and urine. A chronobiological methodology has been adopted to establish the reference values of these two metals in biological samples. It has been observed that the daily intake of copper is within the recommended value, whereas its urinary excretion is high. The daily intake of zinc is below the recommended value and its urinary excretion is also high. Both the metals showed a temporal oscillation pattern in blood and urine. A possible chronic zinc deficiency has been anticipated in this particular ethnic group of vegetarian food habit.

Electric Transport Traction Power Supply System With Distributed Energy Sources

NASA Astrophysics Data System (ADS)

Abramov, E. Y.; Schurov, N. I.; Rozhkova, M. V.

2016-04-01

The paper states the problem of traction substation (TSS) leveling of daily-load curve for urban electric transport. The circuit of traction power supply system (TPSS) with distributed autonomous energy source (AES) based on photovoltaic (PV) and energy storage (ES) units is submitted here. The distribution algorithm of power flow for the daily traction load curve leveling is also introduced in this paper. In addition, it illustrates the implemented experiment model of power supply system.

Forecasting daily passenger traffic volumes in the Moscow metro

NASA Astrophysics Data System (ADS)

Ivanov, V. V.; Osetrov, E. S.

2018-01-01

In this paper we have developed a methodology for the medium-term prediction of daily volumes of passenger traffic in the Moscow metro. It includes three options for the forecast: (1) based on artificial neural networks (ANNs), (2) singular-spectral analysis implemented in the Caterpillar-SSA package, and (3) a combination of the ANN and Caterpillar-SSA approaches. The methods and algorithms allow the mediumterm forecasting of passenger traffic flows in the Moscow metro with reasonable accuracy.

Landscape and flow metrics affecting the distribution of a federally-threatened fish: Improving management, model fit, and model transferability

USGS Publications Warehouse

Brewer, Shannon K.; Worthington, Thomas A.; Zhang, Tianjioa; Logue, Daniel R.; Mittelstet, Aaron R.

2016-01-01

Truncated distributions of pelagophilic fishes have been observed across the Great Plains of North America, with water use and landscape fragmentation implicated as contributing factors. Developing conservation strategies for these species is hindered by the existence of multiple competing flow regime hypotheses related to species persistence. Our primary study objective was to compare the predicted distributions of one pelagophil, the Arkansas River Shiner Notropis girardi, constructed using different flow regime metrics. Further, we investigated different approaches for improving temporal transferability of the species distribution model (SDM). We compared four hypotheses: mean annual flow (a baseline), the 75th percentile of daily flow, the number of zero-flow days, and the number of days above 55th percentile flows, to examine the relative importance of flows during the spawning period. Building on an earlier SDM, we added covariates that quantified wells in each catchment, point source discharges, and non-native species presence to a structured variable framework. We assessed the effects on model transferability and fit by reducing multicollinearity using Spearman’s rank correlations, variance inflation factors, and principal component analysis, as well as altering the regularization coefficient (β) within MaxEnt. The 75th percentile of daily flow was the most important flow metric related to structuring the species distribution. The number of wells and point source discharges were also highly ranked. At the default level of β, model transferability was improved using all methods to reduce collinearity; however, at higher levels of β, the correlation method performed best. Using β = 5 provided the best model transferability, while retaining the majority of variables that contributed 95% to the model. This study provides a workflow for improving model transferability and also presents water-management options that may be considered to improve the conservation status of pelagophils.

40 CFR 439.12 - Effluent limitations attainable by the application of the best practicable control technology...

Code of Federal Regulations, 2011 CFR

2011-07-01

... percent reduction in the long-term average daily BOD5 load of the raw (untreated) process wastewater, multiplied by a variability factor of 3.0. (1) The long-term average daily BOD5 load of the raw process... concentration value reflecting a reduction in the long-term average daily COD load in the raw (untreated...

40 CFR 439.12 - Effluent limitations attainable by the application of the best practicable control technology...

Code of Federal Regulations, 2010 CFR

2010-07-01

... percent reduction in the long-term average daily BOD5 load of the raw (untreated) process wastewater, multiplied by a variability factor of 3.0. (1) The long-term average daily BOD5 load of the raw process... concentration value reflecting a reduction in the long-term average daily COD load in the raw (untreated...

In Search of Coherence: To What Extent Is the Level of Congruence between Daily Actions and Espousals of Middle School Principals?

ERIC Educational Resources Information Center

Tesauro, Michele Blanche

2012-01-01

Research discloses that principals' effectiveness influences student success (Stronge, 2008). This study examined the extent of congruence between the daily activities and espousals of four middle school principals, and the extent their daily activities were artifacts of their values and beliefs about leadership. Also, this study examined if…

78 FR 69509 - Self-Regulatory Organizations; BATS Exchange, Inc.; Notice of Filing and Immediate Effectiveness...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-11-19

... of daily financial rewards on the number of SET Credits awarded to CLPs; (3) change the allocation of the daily financial rewards to a set dollar value per CLP in each class of security; and (4) make... Daily Financial Rewards The Exchange is also proposing to amend its Rules in order to base the...

Daily Flow Model of the Delaware River Basin. Main Report.

DTIC Science & Technology

1981-09-01

DATE U.S. Army Engineer District, Philadelphia Sept. 1981 2nd & Chestnut Sts. 13. NUMBER OF PAGES Philadelphia, PA 19106 144 p . 14. MONITORING AGENCY...VOLMEI FOR I DEVELOPMENTE OF A AIYRFLOW MODEL ( O T1 I "I I I. ~ p ~ ---- I i I TABLE OF CONTENTS I Page No. LIST OF FIGURES iii LIST OF TABLES vi I...Sample Duration Table from Program A969 111-35 111-19 Sample Low Flow Table from Program A969 111-38 111-20 Sample Log- P .?arson Low Flow Frequency

Determination of Vitamin E in Cereal Products and Biscuits by GC-FID.

PubMed

Pasias, Ioannis N; Kiriakou, Ioannis K; Papakonstantinou, Lila; Proestos, Charalampos

2018-01-01

A rapid, precise and accurate method for the determination of vitamin E (α-tocopherol) in cereal products and biscuits has been developed. The uncertainty was calculated for the first time, and the methods were performed for different cereal products and biscuits, characterized as "superfoods". The limits of detection and quantification were calculated. The accuracy and precision were estimated using the certified reference material FAPAS T10112QC, and the determined values were in good accordance with the certified values. The health claims according to the daily reference values for vitamin E were calculated, and the results proved that the majority of the samples examined showed a percentage daily value higher than 15%.

Determination of Vitamin E in Cereal Products and Biscuits by GC-FID

PubMed Central

Kiriakou, Ioannis K.; Papakonstantinou, Lila

2018-01-01

A rapid, precise and accurate method for the determination of vitamin E (α-tocopherol) in cereal products and biscuits has been developed. The uncertainty was calculated for the first time, and the methods were performed for different cereal products and biscuits, characterized as “superfoods”. The limits of detection and quantification were calculated. The accuracy and precision were estimated using the certified reference material FAPAS T10112QC, and the determined values were in good accordance with the certified values. The health claims according to the daily reference values for vitamin E were calculated, and the results proved that the majority of the samples examined showed a percentage daily value higher than 15%. PMID:29301245

Occurrence analysis of daily rainfalls through non-homogeneous Poissonian processes

NASA Astrophysics Data System (ADS)

Sirangelo, B.; Ferrari, E.; de Luca, D. L.

2011-06-01

A stochastic model based on a non-homogeneous Poisson process, characterised by a time-dependent intensity of rainfall occurrence, is employed to explain seasonal effects of daily rainfalls exceeding prefixed threshold values. The data modelling has been performed with a partition of observed daily rainfall data into a calibration period for parameter estimation and a validation period for checking on occurrence process changes. The model has been applied to a set of rain gauges located in different geographical areas of Southern Italy. The results show a good fit for time-varying intensity of rainfall occurrence process by 2-harmonic Fourier law and no statistically significant evidence of changes in the validation period for different threshold values.

Evaluation of Water Use Efficiency of Short Rotation Poplar Coppice at Bohemian-Moravian Highlands

NASA Astrophysics Data System (ADS)

Hlaváčová, Marcela; Fischer, Milan; Mani Tripathi, Abhishek; Orság, Matěj; Trnka, Miroslav

2015-04-01

The water availability of the locality constitutes one of the main constraint for short rotation coppices grown on arable land. As a convenient characteristic assessing how the water use is coupled with the biomass yields, so called water use efficiency (WUE) is proposed. One method of water use efficiency determination is presented within this study. The study was carried out at short rotation poplar coppice (poplar clone J-105) at the Test Station Domanínek, Ltd. at Bohemian-Moravian Highlands during the growing season 2013. Diameters at breast height (DBH) were measured for 16 sample trees where sap flow measuring systems (Granier's Thermal Dissipation Probe, TDP) were installed. TDP outputs are expressed as temperature differences (ΔT) between the heated and non-heated probes. Estimation of sap flux density (Fd) by the Granier method relies on the measurement of temperature difference (ΔT). Determination of maximum temperature difference (ΔTmax) is fundamental for sap flux density (Fd) calculation. Although ΔTmax can be theoretically defined as ΔT at Fd = 0, many factors may prevent the occurrence of the zero flow state, such as night-time water movement for new growth (vegetative or reproductive) or water loss from the canopy due to high vapour pressure deficit (VPD). Therefore, the VPD condition was established for determination of ΔTmax. VPD condition was established as follows: VPD reaching values 0.2 at least 6 hours during night (from 21 p. m. to 3 a. m. and when the condition was fullfilled, the value at 3 a. m. was taken) because it is a supposed time after that the tree has no transpiration. The programmable part of Mini 32 software (www.emsbrno.cz) was used for application of the script establishing ΔTmax values under this VPD condition. Nevertheless, another script was applied on ΔT data set to determination of ΔTmax values for every night at 3 a. m. (as this is when ΔT should be at its daily maximum) without VPD condition restriction for comparison of both approaches. Since application of the two mentioned scripts led to two sets of resulting values, calculations of Fd and consequent sap flow values were computed for both variants of ΔTmaxvalues. The sample trees were divided into 3 diameter classes according to DBH values at the beginning of regular measurements (April 24, 2013). Allometry was carried out on February 20, 2014 to calculation of aboveground woody biomass. The input data for calculations of WUE of aboveground woody biomass productivity was biomass increments and monthly totals of sap flow for 16 sample trees. The total WUE for 16 measured trees reached 4.93 g kg-1 (when calculated with data set without VPD condition) and 4.63 g kg-1 (when calculated with data set under VPD condition). This study was funded by project "Building up a multidisciplinary scientific team focused on drought" No. CZ.1.07/2.3.00/20.0248 and LD130030 supporting COST Action ES1106.

A comparison between one year of daily global irradiation from ground-based measurements versus meteosat images from seven locations in Tunisia

DOE Office of Scientific and Technical Information (OSTI.GOV)

Djemaa, A.B.; Delorme, C.

1992-01-01

Three numerical images from METEOSAT B2 per day have been processed over a period of 12 months, from October 1985 to September 1986, to estimate the daily values of available solar radiation in Tunisia. The methodology used, GISTEL, on the images of the visible' channel of METEOSAT, is described. Results are compared with measured radiation values from seven stations of the Institut de la Meteorologie de Tunisie.' Among more than 2,200 measured-estimated daily pairs, a high percentage, 89%, show a relative error of + or {minus}10%. Many figures concerning Sidi-Bou-Said, Kairouan, Thala, and Gafsa are presented to show the capabilitymore » of GISTEL to map the daily available solar radiation with a sufficient spatial resolution in countries where radiation measurements are too scarce.« less

Memory persistency and nonlinearity in daily mean dew point across India

NASA Astrophysics Data System (ADS)

Ray, Rajdeep; Khondekar, Mofazzal Hossain; Ghosh, Koushik; Bhattacharjee, Anup Kumar

2016-04-01

Enterprising endeavour has been taken in this work to realize and estimate the persistence in memory of the daily mean dew point time series obtained from seven different weather stations viz. Kolkata, Chennai (Madras), New Delhi, Mumbai (Bombay), Bhopal, Agartala and Ahmedabad representing different geographical zones in India. Hurst exponent values reveal an anti-persistent behaviour of these dew point series. To affirm the Hurst exponent values, five different scaling methods have been used and the corresponding results are compared to synthesize a finer and reliable conclusion out of it. The present analysis also bespeaks that the variation in daily mean dew point is governed by a non-stationary process with stationary increments. The delay vector variance (DVV) method has been exploited to investigate nonlinearity, and the present calculation confirms the presence of deterministic nonlinear profile in the daily mean dew point time series of the seven stations.

Objective Lightning Forecasting at Kennedy Space Center/Cape Canaveral Air Force Station using Cloud-to-Ground Lightning Surveillance System Data

NASA Technical Reports Server (NTRS)

Lambert, Winifred; Wheeler, Mark

2004-01-01

The 45th Weather Squadron (45 WS) forecasters at Cape Canaveral Air Force Station (CCAFS) in Florida include a probability of thunderstorm occurrence in their daily morning briefings. This information is used by personnel involved in determining the possibility of violating Launch Commit Criteria, evaluating Flight Rules for the Space Shuttle, and daily planning for ground operation activities on Kennedy Space Center (KSC)/CCAFS. Much of the current lightning probability forecast is based on a subjective analysis of model and observational data. The forecasters requested that a lightning probability forecast tool based on statistical analysis of historical warm-season (May - September) data be developed in order to increase the objectivity of the daily thunderstorm probability forecast. The tool is a set of statistical lightning forecast equations that provide a lightning occurrence probability for the day by 1100 UTC (0700 EDT) during the warm season. This study used 15 years (1989-2003) of warm season data to develop the objective forecast equations. The local CCAFS 1000 UTC sounding was used to calculate stability parameters for equation predictors. The Cloud-to-Ground Lightning Surveillance System (CGLSS) data were used to determine lightning occurrence for each day. The CGLSS data have been found to be more reliable indicators of lightning in the area than surface observations through local informal analyses. This work was based on the results from two earlier research projects. Everitt (1999) used surface observations and rawinsonde data to develop logistic regression equations that forecast the daily thunderstorm probability at CCAFS. The Everitt (1999) equations showed an improvement in skill over the Neumann-Pfeffer thunderstorm index (Neumann 1971), which uses multiple linear regression, and also persistence and climatology forecasts. Lericos et al. (2002) developed lightning distributions over the Florida peninsula based on specific flow regimes. The flow regimes were inferred from the average wind direction in the 1000-700 mb layer at Miami (MIA), Tampa (TBW), and Jacksonville (JAX), Florida, and the lightning data were from the National Lightning Detection Network. The results suggested that the daily flow regime may be an important predictor of lightning occurrence on KSC/CCAFS.

Meteorological Trigger Conditions for Different Geomorphic Processes in Steep Mountain Channels in the Austrian Alps

NASA Astrophysics Data System (ADS)

Kaitna, R.; Braun, M.

2016-12-01

Steep mountain channels episodically can experience very different geomorphic processes, ranging from flash floods, intensive bedload transport, debris floods, and debris flows. Rainfall-related trigger conditions and geomorphic disposition for each of these processes to occur, as well as conditions leading to one process and not to the other, are not well understood. In this contribution, we analyze triggering rainfalls for all documented events in the Eastern (Austrian) Alps on a daily and sub-daily basis. The analysis with daily rainfall data covers more than 6640 events between 1901 and 2014 and the analysis based on sub-daily (10 min interval) rainfall data includes around 950 events between 1992 and 2014. Of the four investigated event types, we find that debris flows are typically associated with the least cumulative rainfall, while intensive bedload transport as well as torrential floods occur when there is a substantial amount of cumulative rainfall. Debris floods are occurring on average with cumulative rainfall in a range between the aforementioned processes. Comparison of historical data shows, that about 90% of events are triggered with a combination of extreme rainfall and temperature. Bayesian analysis reveals that a high degree of geomorphic events is associated with very short rainfall durations that cannot be resolved with daily rainfall data. A comparison of both datasets shows that subdaily data gives more accurate results. Additionally, we find a high degree of regional differences, e.g. between regions north and south of the Alpine chain or high or low Alpine regions. There is indication that especially debris flows need less total rainfall amount when occurring in regions with a high relief energy than in less steep environments. The limitation of our analysis is mainly due to the distance between the locations of event triggering and rainfall measurement and the definition of rainfall events for the Bayesian analysis. In a next step, we will connect our results with the analyses of the hydrological as well as geomorphological disposition in selected study regions and with projections of changing climate conditions.

Computation and analysis of the instantaneous-discharge record for the Colorado River at Lees Ferry, Arizona : May 8, 1921, through September 30, 2000

USGS Publications Warehouse

Topping, David J.; Schmidt, John C.; Vierra, L.E.

2003-01-01

A gaging station has been operated by the U.S. Geological Survey at Lees Ferry, Arizona, since May 8, 1921. In March 1963, Glen Canyon Dam was closed 15.5 miles upstream, cutting off the upstream sediment supply and regulating the discharge of the Colorado River at Lees Ferry for the first time in history. To evaluate the pre-dam variability in the hydrology of the Colorado River, and to determine the effect of the operation of Glen Canyon Dam on the downstream hydrology of the river, a continuous record of the instantaneous discharge of the river at Lees Ferry was constructed and analyzed for the entire period of record between May 8, 1921, and September 30, 2000. This effort involved retrieval from the Federal Records Centers and then synthesis of all the raw historical data collected by the U.S. Geological Survey at Lees Ferry. As part of this process, the peak discharges of the two largest historical floods at Lees Ferry, the 1884 and 1921 floods, were reanalyzed and recomputed. This reanalysis indicates that the peak discharge of the 1884 flood was 210,000?30,000 cubic feet per second (ft3/s), and the peak discharge of the 1921 flood was 170,000?20,000 ft3/s. These values are indistinguishable from the peak discharges of these floods originally estimated or published by the U.S. Geological Survey, but are substantially less than the currently accepted peak discharges of these floods. The entire continuous record of instantaneous discharge of the Colorado River at Lees Ferry can now be requested from the U.S. Geological Survey Grand Canyon Monitoring and Research Center, Flagstaff, Arizona, and is also available electronically at http://www.gcmrc.gov. This record is perhaps the longest (almost 80 years) high-resolution (mostly 15- to 30-minute precision) times series of river discharge available. Analyses of these data, therefore, provide an unparalleled characterization of both the natural variability in the discharge of a river and the effects of dam operations on a river. Following the construction and quality-control checks of the continuous record of instantaneous discharge, analyses of flow duration, sub-daily flow variability, and flood frequency were conducted on the pre- and post-dam parts of the record. These analyses indicate that although the discharge of the Colorado River varied substantially prior to the closure of Glen Canyon Dam in 1963, operation of the dam has caused changes in discharge that are more extreme than the pre-dam natural variability. Operation of the dam has eliminated flood flows and base flows, and thereby has effectively 'flattened' the annual hydrograph. Prior to closure of the dam, the discharge of the Colorado River at Lees Ferry was lower than 7,980 ft3/s half of the time. Discharges lower than about 9,000 ft3/s were important for the seasonal accumulation and storage of sand in the pre-dam river downstream from Lees Ferry. The current operating plan for Glen Canyon Dam no longer allows sustained discharges lower than 8,000 ft3/s to be released. Thus, closure of the dam has not only cut off the upstream supply of sediment, but operation of the dam has also largely eliminated discharges during which sand could be demonstrated to accumulate in the river. In addition to radically changing the hydrology of the river, operation of the dam for hydroelectric-power generation has introduced large daily fluctuations in discharge. During the pre-dam era, the median daily range in discharge was only 542 ft3/s, although daily ranges in discharge exceeding 20,000 ft3/s were observed during the summer thunderstorm season. Relative to the pre-dam period of record, dam operations have increased the daily range in discharge during all but 0.1 percent of all days. The post-dam median daily range in discharge, 8,580 ft3/s, exceeds the pre-dam median discharge of 7,980 ft3/s. Operation of the dam has also radically changed the frequency of floods on the Colorado River at Lees Ferry. The frequency of f

Hierarchicality of trade flow networks reveals complexity of products.

PubMed

Shi, Peiteng; Zhang, Jiang; Yang, Bo; Luo, Jingfei

2014-01-01

With globalization, countries are more connected than before by trading flows, which amounts to at least 36 trillion dollars today. Interestingly, around 30-60 percents of exports consist of intermediate products in global. Therefore, the trade flow network of particular product with high added values can be regarded as value chains. The problem is weather we can discriminate between these products from their unique flow network structure? This paper applies the flow analysis method developed in ecology to 638 trading flow networks of different products. We claim that the allometric scaling exponent η can be used to characterize the degree of hierarchicality of a flow network, i.e., whether the trading products flow on long hierarchical chains. Then, it is pointed out that the flow networks of products with higher added values and complexity like machinary, transport equipment etc. have larger exponents, meaning that their trade flow networks are more hierarchical. As a result, without the extra data like global input-output table, we can identify the product categories with higher complexity, and the relative importance of a country in the global value chain by the trading network solely.

Hierarchicality of Trade Flow Networks Reveals Complexity of Products

PubMed Central

Shi, Peiteng; Zhang, Jiang; Yang, Bo; Luo, Jingfei

2014-01-01

With globalization, countries are more connected than before by trading flows, which amounts to at least trillion dollars today. Interestingly, around percents of exports consist of intermediate products in global. Therefore, the trade flow network of particular product with high added values can be regarded as value chains. The problem is weather we can discriminate between these products from their unique flow network structure? This paper applies the flow analysis method developed in ecology to 638 trading flow networks of different products. We claim that the allometric scaling exponent can be used to characterize the degree of hierarchicality of a flow network, i.e., whether the trading products flow on long hierarchical chains. Then, it is pointed out that the flow networks of products with higher added values and complexity like machinary, transport equipment etc. have larger exponents, meaning that their trade flow networks are more hierarchical. As a result, without the extra data like global input-output table, we can identify the product categories with higher complexity, and the relative importance of a country in the global value chain by the trading network solely. PMID:24905753

Estimation of Flow Duration Curve for Ungauged Catchments using Adaptive Neuro-Fuzzy Inference System and Map Correlation Method: A Case Study from Turkey

NASA Astrophysics Data System (ADS)

Kentel, E.; Dogulu, N.

2015-12-01

In Turkey the experience and data required for a hydrological model setup is limited and very often not available. Moreover there are many ungauged catchments where there are also many planned projects aimed at utilization of water resources including development of existing hydropower potential. This situation makes runoff prediction at locations with lack of data and ungauged locations where small hydropower plants, reservoirs, etc. are planned an increasingly significant challenge and concern in the country. Flow duration curves have many practical applications in hydrology and integrated water resources management. Estimation of flood duration curve (FDC) at ungauged locations is essential, particularly for hydropower feasibility studies and selection of the installed capacities. In this study, we test and compare the performances of two methods for estimating FDCs in the Western Black Sea catchment, Turkey: (i) FDC based on Map Correlation Method (MCM) flow estimates. MCM is a recently proposed method (Archfield and Vogel, 2010) which uses geospatial information to estimate flow. Flow measurements of stream gauging stations nearby the ungauged location are the only data requirement for this method. This fact makes MCM very attractive for flow estimation in Turkey, (ii) Adaptive Neuro-Fuzzy Inference System (ANFIS) is a data-driven method which is used to relate FDC to a number of variables representing catchment and climate characteristics. However, it`s ease of implementation makes it very useful for practical purposes. Both methods use easily collectable data and are computationally efficient. Comparison of the results is realized based on two different measures: the root mean squared error (RMSE) and the Nash-Sutcliffe Efficiency (NSE) value. Ref: Archfield, S. A., and R. M. Vogel (2010), Map correlation method: Selection of a reference streamgage to estimate daily streamflow at ungaged catchments, Water Resour. Res., 46, W10513, doi:10.1029/2009WR008481.

Technique for estimation of streamflow statistics in mineral areas of interest in Afghanistan

USGS Publications Warehouse

Olson, Scott A.; Mack, Thomas J.

2011-01-01

A technique for estimating streamflow statistics at ungaged stream sites in areas of mineral interest in Afghanistan using drainage-area-ratio relations of historical streamflow data was developed and is documented in this report. The technique can be used to estimate the following streamflow statistics at ungaged sites: (1) 7-day low flow with a 10-year recurrence interval, (2) 7-day low flow with a 2-year recurrence interval, (3) daily mean streamflow exceeded 90 percent of the time, (4) daily mean streamflow exceeded 80 percent of the time, (5) mean monthly streamflow for each month of the year, (6) mean annual streamflow, and (7) minimum monthly streamflow for each month of the year. Because they are based on limited historical data, the estimates of streamflow statistics at ungaged sites are considered preliminary.

Reconnaissance of Stream Geomorphology, Low Streamflow, and Stream Temperature in the Mountaintop Coal-Mining Region, Southern West Virginia, 1999-2000

USGS Publications Warehouse

Wiley, Jeffrey B.; Evaldi, Ronald D.; Eychaner, James H.; Chambers, Douglas B.

2001-01-01

The effects of mountaintop removal coal mining and the valley fills created by this mining method in southern West Virginia were investigated by comparing data collected at valley-fill, mined, and unmined sites. Bed material downstream of valley-fill sites had a greater number of particles less than 2 millimeters and a smaller median particle size than the mined and unmined sites. At the 84th percentile of sampled data, however, bed material at each site type had about the same size particles. Bankfull cross-sectional areas at a riffle section were approximately equal at valley-fill and unmined sites, but not enough time has passed and insufficient streamflows since the land was disturbed may have prevented the stream channel at valley-fill sites from reaching equilibrium. The 90-percent flow durations at valley-fill sites generally were 6-7 times greater than at unmined sites. Some valley-fill sites, however, exhibited streamflows similar to unmined sites, and some unmined sites exhibited streamflows similar to valley-fill sites. Daily streamflows from valley-fill sites generally are greater than daily streamflows from unmined sites during periods of low streamflow. Valley-fill sites have a greater percentage of base-flow and a lower percentage of flow from storm runoff than unmined sites. Water temperatures from a valley-fill site exhibited lower daily fluctuations and seasonal variations than water temperatures from an unmined site.

Mobile phones in a traffic flow: a geographical perspective to evening rush hour traffic analysis using call detail records.

PubMed

Järv, Olle; Ahas, Rein; Saluveer, Erki; Derudder, Ben; Witlox, Frank

2012-01-01

Excessive land use and suburbanisation around densely populated urban areas has gone hand in hand with a growth in overall transportation and discussions about causality of traffic congestions. The objective of this paper is to gain new insight regarding the composition of traffic flows, and to reveal how and to what extent suburbanites' travelling affects rush hour traffic. We put forward an alternative methodological approach using call detail records of mobile phones to assess the composition of traffic flows during the evening rush hour in Tallinn, Estonia. We found that daily commuting and suburbanites influence transportation demand by amplifying the evening rush hour traffic, although daily commuting trips comprises only 31% of all movement at that time. The geography of the Friday evening rush hour is distinctive from other working days, presumably in connection with domestic tourism and leisure time activities. This suggests that the rise of the overall mobility of individuals due to societal changes may play a greater role in evening rush hour traffic conditions than does the impact of suburbanisation.

Mobile Phones in a Traffic Flow: A Geographical Perspective to Evening Rush Hour Traffic Analysis Using Call Detail Records

PubMed Central

Järv, Olle; Ahas, Rein; Saluveer, Erki; Derudder, Ben; Witlox, Frank

2012-01-01

Excessive land use and suburbanisation around densely populated urban areas has gone hand in hand with a growth in overall transportation and discussions about causality of traffic congestions. The objective of this paper is to gain new insight regarding the composition of traffic flows, and to reveal how and to what extent suburbanites’ travelling affects rush hour traffic. We put forward an alternative methodological approach using call detail records of mobile phones to assess the composition of traffic flows during the evening rush hour in Tallinn, Estonia. We found that daily commuting and suburbanites influence transportation demand by amplifying the evening rush hour traffic, although daily commuting trips comprises only 31% of all movement at that time. The geography of the Friday evening rush hour is distinctive from other working days, presumably in connection with domestic tourism and leisure time activities. This suggests that the rise of the overall mobility of individuals due to societal changes may play a greater role in evening rush hour traffic conditions than does the impact of suburbanisation. PMID:23155461

Generating daily weather data for ecosystem modelling in the Congo River Basin

NASA Astrophysics Data System (ADS)

Petritsch, Richard; Pietsch, Stephan A.

2010-05-01

Daily weather data are an important constraint for diverse applications in ecosystem research. In particular, temperature and precipitation are the main drivers for forest ecosystem productivity. Mechanistic modelling theory heavily relies on daily values for minimum and maximum temperatures, precipitation, incident solar radiation and vapour pressure deficit. Although the number of climate measurement stations increased during the last centuries, there are still regions with limited climate data. For example, in the WMO database there are only 16 stations located in Gabon with daily weather measurements. Additionally, the available time series are heavily affected by measurement errors or missing values. In the WMO record for Gabon, on average every second day is missing. Monthly means are more robust and may be estimated over larger areas. Therefore, a good alternative is to interpolate monthly mean values using a sparse network of measurement stations, and based on these monthly data generate daily weather data with defined characteristics. The weather generator MarkSim was developed to produce climatological time series for crop modelling in the tropics. It provides daily values for maximum and minimum temperature, precipitation and solar radiation. The monthly means can either be derived from the internal climate surfaces or prescribed as additional inputs. We compared the generated outputs observations from three climate stations in Gabon (Lastourville, Moanda and Mouilla) and found that maximum temperature and solar radiation were heavily overestimated during the long dry season. This is due to the internal dependency of the solar radiation estimates to precipitation. With no precipitation a cloudless sky is assumed and thus high incident solar radiation and a large diurnal temperature range. However, in reality it is cloudy in the Congo River Basin during the long dry season. Therefore, we applied a correction factor to solar radiation and temperature range based on the ratio of values on rainy days and days without rain, respectively. For assessing the impact of our correction, we simulated the ecosystem behaviour using the climate data from Lastourville, Moanda and Mouilla with the mechanistic ecosystem model Biome-BGC. Differences in terms of the carbon, nitrogen and water cycle were subsequently analysed and discussed.

Weekly vs. daily administration of oral methotrexate (MTX) for generalized plaque psoriasis: a randomized controlled clinical trial.

PubMed

Radmanesh, Mohammad; Rafiei, Behnam; Moosavi, Zahra-Beigum; Sina, Niloofar

2011-10-01

Methotrexate (MTX) treatment for psoriasis is most often administered weekly, because the drug has been considered more hepatotoxic when taken daily. However, some patients may tolerate smaller, more frequent doses better. To study the efficacy and toxicity of daily vs. weekly MTX. In a randomized controlled trial, 101 patients with generalized plaque psoriasis received oral MTX 2.5 mg daily for weeks, 4 weeks and monthly for a total of 4 months. Changes in PASI scores were classified into three categories: >75% improvement was considered significant; 25-75% moderate; and <25% poor. Sixty Group 1 patients and 81 Group 2 patients showed a significant response (P-value 0.001); 19 patients in Group 1 and 14 in Group 2 responded moderately; 22 patients in Group 1 and six patients from Group 2 responded poorly. Forty-five patients in Group 1 and 33 in Group 2 developed transient increases in liver enzymes (P-value 0.11). Nausea, headache, fatigue, and gastrointestinal upset were noted in four Group 1 patients and 30 Group 2 patients (P-value 0.0001). Nausea, vomiting, headache, and fatigue were significantly less common side effects in our patients who received MTX daily, but liver enzyme abnormalities were less common, and clinical efficacy was greater in the patients who received MTX weekly. © 2011 The International Society of Dermatology.

Bottlenecks in Geospatial Data-Driven Decision-Making for Natural Disaster Management: A Case Study of Forest Fire Prevention and Control in Guatemala's Maya Biosphere Reserve

NASA Astrophysics Data System (ADS)

Berenter, J. S.; Mueller, J. M.; Morrison, I.

2016-12-01

Annual forest fires are a source of great economic and environmental cost in the Maya Biosphere Reserve (MBR), a region of high ecological and historical value in Guatemala's department of Petén. Scarce institutional resources, limited local response capacity, and difficult terrain place a premium on the use of Earth observation data for forest fire management in the MBR, but also present significant institutional barriers to optimizing the value of this data. Drawing upon key informant interviews and a contingent valuation survey of national and local actors conducted during a three-year performance evaluation of the USAID/NASA Regional Visualization and Monitoring System (SERVIR), this paper traces the flow of SERVIR data from acquisition to decision in order to assess the institutional and contextual factors affecting the value of Earth observation data for forest fire management in the MBR. Findings indicate that the use of satellite data for forest fire management in the MBR is widespread and multi-dimensional: historical assessments of land use and land cover, fire scarring, and climate data help central-level fire management agencies identify and regulate fire-sensitive areas; regular monitoring and dissemination of climate data enables coordination between agricultural burning activities and fire early warning systems; and daily satellite detection of thermal anomalies in land surface temperature permits first responders to monitor and react to "hotspot" activity. Findings also suggest, however, that while the decentralized operations of Petén's fire management systems foster the use of Earth observation data, systemic bottlenecks, including budgetary constraints, inadequate data infrastructure and interpretation capacity, and obstacles to regulatory enforcement, impede the flow of information and use of technology and thus impact the value of that data, particularly in remote and under-resourced areas of the MBR. A geographic expansion and fortification of support systems for use of Earth observation data is thus required to maximize the value of data-driven forest fire management in the MBR. Findings further validate a need for continued cooperation between scientific and governance institutions to disseminate and integrate geospatial data into environmental decision-making.

Cultural orientations, daily activities, and adjustment in Mexican American youth.

PubMed

McHale, Susan M; Updegraff, Kimberly A; Kim, Ji-Yeon; Cansler, Emily

2009-05-01

The links between youth's daily activities and adjustment and the role of cultural practices and values in these links were studied in 469 youth from 237 Mexican American families. In home interviews, data on mothers', fathers', and two adolescent-age siblings' cultural practices (language use, social contacts) and values (for familism, for education achievement) were collected, along with data on youth risky behavior and depressive symptoms. In 7 nightly phone calls, youth reported on their day's free time activities (i.e., sports, academics, religious activities, television viewing, and hanging out). Analyses revealed that youth who spent more time in unsupervised hanging out reported more depressive symptoms and risky behavior, and those who spent more time in academic activities reported less risky behavior. Results also indicated that more Anglo-oriented youth spent more time in sports, that more Mexican-oriented youth spent more time watching television, that fathers' familism values were related to youth's time in religious activities, and that parents' educational values were linked to youth's time in academic activities. Some evidence indicated that parents' cultural practices and values, particularly fathers', moderated the links between daily activities and youth adjustment.