Stream hydrologic response to increased urbanization in Mid-Atlantic watersheds

EPA Science Inventory

Urban development alters stream hydrology; resulting in increases in the Richard-Baker Flashiness index, peak flow, and the number of flood events for many watersheds throughout the U.S. To better understand and predict the relationship between stream flow patterns and watershed ...

Estimating peak-flow frequency statistics for selected gaged and ungaged sites in naturally flowing streams and rivers in Idaho

USGS Publications Warehouse

Wood, Molly S.; Fosness, Ryan L.; Skinner, Kenneth D.; Veilleux, Andrea G.

2016-06-27

The U.S. Geological Survey, in cooperation with the Idaho Transportation Department, updated regional regression equations to estimate peak-flow statistics at ungaged sites on Idaho streams using recent streamflow (flow) data and new statistical techniques. Peak-flow statistics with 80-, 67-, 50-, 43-, 20-, 10-, 4-, 2-, 1-, 0.5-, and 0.2-percent annual exceedance probabilities (1.25-, 1.50-, 2.00-, 2.33-, 5.00-, 10.0-, 25.0-, 50.0-, 100-, 200-, and 500-year recurrence intervals, respectively) were estimated for 192 streamgages in Idaho and bordering States with at least 10 years of annual peak-flow record through water year 2013. The streamgages were selected from drainage basins with little or no flow diversion or regulation. The peak-flow statistics were estimated by fitting a log-Pearson type III distribution to records of annual peak flows and applying two additional statistical methods: (1) the Expected Moments Algorithm to help describe uncertainty in annual peak flows and to better represent missing and historical record; and (2) the generalized Multiple Grubbs Beck Test to screen out potentially influential low outliers and to better fit the upper end of the peak-flow distribution. Additionally, a new regional skew was estimated for the Pacific Northwest and used to weight at-station skew at most streamgages. The streamgages were grouped into six regions (numbered 1_2, 3, 4, 5, 6_8, and 7, to maintain consistency in region numbering with a previous study), and the estimated peak-flow statistics were related to basin and climatic characteristics to develop regional regression equations using a generalized least squares procedure. Four out of 24 evaluated basin and climatic characteristics were selected for use in the final regional peak-flow regression equations.Overall, the standard error of prediction for the regional peak-flow regression equations ranged from 22 to 132 percent. Among all regions, regression model fit was best for region 4 in west-central Idaho (average standard error of prediction=46.4 percent; pseudo-R2>92 percent) and region 5 in central Idaho (average standard error of prediction=30.3 percent; pseudo-R2>95 percent). Regression model fit was poor for region 7 in southern Idaho (average standard error of prediction=103 percent; pseudo-R2<78 percent) compared to other regions because few streamgages in region 7 met the criteria for inclusion in the study, and the region’s semi-arid climate and associated variability in precipitation patterns causes substantial variability in peak flows.A drainage area ratio-adjustment method, using ratio exponents estimated using generalized least-squares regression, was presented as an alternative to the regional regression equations if peak-flow estimates are desired at an ungaged site that is close to a streamgage selected for inclusion in this study. The alternative drainage area ratio-adjustment method is appropriate for use when the drainage area ratio between the ungaged and gaged sites is between 0.5 and 1.5.The updated regional peak-flow regression equations had lower total error (standard error of prediction) than all regression equations presented in a 1982 study and in four of six regions presented in 2002 and 2003 studies in Idaho. A more extensive streamgage screening process used in the current study resulted in fewer streamgages used in the current study than in the 1982, 2002, and 2003 studies. Fewer streamgages used and the selection of different explanatory variables were likely causes of increased error in some regions compared to previous studies, but overall, regional peak‑flow regression model fit was generally improved for Idaho. The revised statistical procedures and increased streamgage screening applied in the current study most likely resulted in a more accurate representation of natural peak-flow conditions.The updated, regional peak-flow regression equations will be integrated in the U.S. Geological Survey StreamStats program to allow users to estimate basin and climatic characteristics and peak-flow statistics at ungaged locations of interest. StreamStats estimates peak-flow statistics with quantifiable certainty only when used at sites with basin and climatic characteristics within the range of input variables used to develop the regional regression equations. Both the regional regression equations and StreamStats should be used to estimate peak-flow statistics only in naturally flowing, relatively unregulated streams without substantial local influences to flow, such as large seeps, springs, or other groundwater-surface water interactions that are not widespread or characteristic of the respective region.

Effectiveness of the New Hampshire stream-gaging network in providing regional streamflow information

USGS Publications Warehouse

Olson, Scott A.

2003-01-01

The stream-gaging network in New Hampshire was analyzed for its effectiveness in providing regional information on peak-flood flow, mean-flow, and low-flow frequency. The data available for analysis were from stream-gaging stations in New Hampshire and selected stations in adjacent States. The principles of generalized-least-squares regression analysis were applied to develop regional regression equations that relate streamflow-frequency characteristics to watershed characteristics. Regression equations were developed for (1) the instantaneous peak flow with a 100-year recurrence interval, (2) the mean-annual flow, and (3) the 7-day, 10-year low flow. Active and discontinued stream-gaging stations with 10 or more years of flow data were used to develop the regression equations. Each stream-gaging station in the network was evaluated and ranked on the basis of how much the data from that station contributed to the cost-weighted sampling-error component of the regression equation. The potential effect of data from proposed and new stream-gaging stations on the sampling error also was evaluated. The stream-gaging network was evaluated for conditions in water year 2000 and for estimated conditions under various network strategies if an additional 5 years and 20 years of streamflow data were collected. The effectiveness of the stream-gaging network in providing regional streamflow information could be improved for all three flow characteristics with the collection of additional flow data, both temporally and spatially. With additional years of data collection, the greatest reduction in the average sampling error of the regional regression equations was found for the peak- and low-flow characteristics. In general, additional data collection at stream-gaging stations with unregulated flow, relatively short-term record (less than 20 years), and drainage areas smaller than 45 square miles contributed the largest cost-weighted reduction to the average sampling error of the regional estimating equations. The results of the network analyses can be used to prioritize the continued operation of active stations, the reactivation of discontinued stations, or the activation of new stations to maximize the regional information content provided by the stream-gaging network. Final decisions regarding altering the New Hampshire stream-gaging network would require the consideration of the many uses of the streamflow data serving local, State, and Federal interests.

Increasing synchrony of high temperature and low flow in western North American streams: double trouble for coldwater biota?

USGS Publications Warehouse

Arismendi, Ivan; Safeeq, Mohammad; Johnson, Sherri L.; Dunham, Jason B.; Haggerty, Roy

2013-01-01

Flow and temperature are strongly linked environmental factors driving ecosystem processes in streams. Stream temperature maxima (Tmax_w) and stream flow minima (Qmin) can create periods of stress for aquatic organisms. In mountainous areas, such as western North America, recent shifts toward an earlier spring peak flow and decreases in low flow during summer/fall have been reported. We hypothesized that an earlier peak flow could be shifting the timing of low flow and leading to a decrease in the interval between Tmax_w and Qmin. We also examined if years with extreme low Qmin were associated with years of extreme high Tmax_w. We tested these hypotheses using long32 term data from 22 minimally human-influenced streams for the period 1950-2010. We found trends toward a shorter time lag between Tmax_w and Qmin over time and a strong negative association between their magnitudes. Our findings show that aquatic biota may be increasingly experiencing narrower time windows to recover or adapt between these extreme events of low flow and high temperature. This study highlights the importance of evaluating multiple environmental drivers to better gauge the effects of the recent climate variability in freshwaters.

Peak-flow characteristics of Wyoming streams

USGS Publications Warehouse

Miller, Kirk A.

2003-01-01

Peak-flow characteristics for unregulated streams in Wyoming are described in this report. Frequency relations for annual peak flows through water year 2000 at 364 streamflow-gaging stations in and near Wyoming were evaluated and revised or updated as needed. Analyses of historical floods, temporal trends, and generalized skew were included in the evaluation. Physical and climatic basin characteristics were determined for each gaging station using a geographic information system. Gaging stations with similar peak-flow and basin characteristics were grouped into six hydrologic regions. Regional statistical relations between peak-flow and basin characteristics were explored using multiple-regression techniques. Generalized least squares regression equations for estimating magnitudes of annual peak flows with selected recurrence intervals from 1.5 to 500 years were developed for each region. Average standard errors of estimate range from 34 to 131 percent. Average standard errors of prediction range from 35 to 135 percent. Several statistics for evaluating and comparing the errors in these estimates are described. Limitations of the equations are described. Methods for applying the regional equations for various circumstances are listed and examples are given.

Aquatic insect emergence from headwater streams flowing through regeneration and mature forests in western Oregon

Treesearch

Robert Progar; Andrew R. Moldenke

2009-01-01

We examined the effect of canopy cover on adult aquatic insect emergence by collecting bi-weekly samples from twelve headwater stream reaches flowing either under a mature conifer canopy or streams flowing through ten-year-old regeneration in western Oregon from February to November 1997. Density and biomass generally followed a bimodal curve with peaks during early...

Global characteristics of stream flow seasonality and variability

USGS Publications Warehouse

Dettinger, M.D.; Diaz, Henry F.

2000-01-01

Monthly stream flow series from 1345 sites around the world are used to characterize geographic differences in the seasonality and year-to-year variability of stream flow. Stream flow seasonality varies regionally, depending on the timing of maximum precipitation, evapotranspiration, and contributions from snow and ice. Lags between peaks of precipitation and stream flow vary smoothly from long delays in high-latitude and mountainous regions to short delays in the warmest sectors. Stream flow is most variable from year to year in dry regions of the southwest United States and Mexico, the Sahel, and southern continents, and it varies more (relatively) than precipitation in the same regions. Tropical rivers have the steadiest flows. El Nin??o variations are correlated with stream flow in many parts of the Americas, Europe, and Australia. Many stream flow series from North America, Europe, and the Tropics reflect North Pacific climate, whereas series from the eastern United States, Europe, and tropical South America and Africa reflect North Atlantic climate variations.

Historical changes in annual peak flows in Maine and implications for flood-frequency analyses

USGS Publications Warehouse

Hodgkins, Glenn A.

2010-01-01

To safely and economically design bridges, culverts, and other structures that are in or near streams (fig. 1 for example), it is necessary to determine the magnitude of peak streamflows such as the 100-year flow. Flood-frequency analyses use statistical methods to compute peak flows for selected recurrence intervals (100 years, for example). The recurrence interval is the average number of years between peak flows that are equal to or greater than a specified peak flow. Floodfrequency analyses are based on annual peak flows at a stream. It has long been assumed that annual peak streamflows are stationary over very long periods of time, except in river basins subject to urbanization, regulation, and other direct human activities. Stationarity is the concept that natural systems fluctuate within an envelope of variability that does not change over time (Milly and others, 2008). Because of the potential effects of global warming on peak flows, the assumption of peak-flow stationarity has recently been questioned (Milly and others, 2008). Maine has many streamgaging stations with 50 to 105 years of recorded annual peak streamflows. This long-term record has been tested for historical flood-frequency stationarity, to provide some insight into future flood frequency (Hodgkins, 2010). This fact sheet, prepared by the U.S. Geological Survey (USGS) in cooperation with the Maine Department of Transportation (MaineDOT), provides a partial summary of the results of the study by Hodgkins (2010).

Techniques for Estimating the Magnitude and Frequency of Peak Flows on Small Streams in Minnesota Based on Data through Water Year 2005

USGS Publications Warehouse

Lorenz, David L.; Sanocki, Chris A.; Kocian, Matthew J.

2010-01-01

Knowledge of the peak flow of floods of a given recurrence interval is essential for regulation and planning of water resources and for design of bridges, culverts, and dams along Minnesota's rivers and streams. Statistical techniques are needed to estimate peak flow at ungaged sites because long-term streamflow records are available at relatively few places. Because of the need to have up-to-date peak-flow frequency information in order to estimate peak flows at ungaged sites, the U.S. Geological Survey (USGS) conducted a peak-flow frequency study in cooperation with the Minnesota Department of Transportation and the Minnesota Pollution Control Agency. Estimates of peak-flow magnitudes for 1.5-, 2-, 5-, 10-, 25-, 50-, 100-, and 500-year recurrence intervals are presented for 330 streamflow-gaging stations in Minnesota and adjacent areas in Iowa and South Dakota based on data through water year 2005. The peak-flow frequency information was subsequently used in regression analyses to develop equations relating peak flows for selected recurrence intervals to various basin and climatic characteristics. Two statistically derived techniques-regional regression equation and region of influence regression-can be used to estimate peak flow on ungaged streams smaller than 3,000 square miles in Minnesota. Regional regression equations were developed for selected recurrence intervals in each of six regions in Minnesota: A (northwestern), B (north central and east central), C (northeastern), D (west central and south central), E (southwestern), and F (southeastern). The regression equations can be used to estimate peak flows at ungaged sites. The region of influence regression technique dynamically selects streamflow-gaging stations with characteristics similar to a site of interest. Thus, the region of influence regression technique allows use of a potentially unique set of gaging stations for estimating peak flow at each site of interest. Two methods of selecting streamflow-gaging stations, similarity and proximity, can be used for the region of influence regression technique. The regional regression equation technique is the preferred technique as an estimate of peak flow in all six regions for ungaged sites. The region of influence regression technique is not appropriate for regions C, E, and F because the interrelations of some characteristics of those regions do not agree with the interrelations throughout the rest of the State. Both the similarity and proximity methods for the region of influence technique can be used in the other regions (A, B, and D) to provide additional estimates of peak flow. The peak-flow-frequency estimates and basin characteristics for selected streamflow-gaging stations and regional peak-flow regression equations are included in this report.

StreamStats in Oklahoma - Drainage-Basin Characteristics and Peak-Flow Frequency Statistics for Ungaged Streams

USGS Publications Warehouse

Smith, S. Jerrod; Esralew, Rachel A.

2010-01-01

The USGS Streamflow Statistics (StreamStats) Program was created to make geographic information systems-based estimation of streamflow statistics easier, faster, and more consistent than previously used manual techniques. The StreamStats user interface is a map-based internet application that allows users to easily obtain streamflow statistics, basin characteristics, and other information for user-selected U.S. Geological Survey data-collection stations and ungaged sites of interest. The application relies on the data collected at U.S. Geological Survey streamflow-gaging stations, computer aided computations of drainage-basin characteristics, and published regression equations for several geographic regions comprising the United States. The StreamStats application interface allows the user to (1) obtain information on features in selected map layers, (2) delineate drainage basins for ungaged sites, (3) download drainage-basin polygons to a shapefile, (4) compute selected basin characteristics for delineated drainage basins, (5) estimate selected streamflow statistics for ungaged points on a stream, (6) print map views, (7) retrieve information for U.S. Geological Survey streamflow-gaging stations, and (8) get help on using StreamStats. StreamStats was designed for national application, with each state, territory, or group of states responsible for creating unique geospatial datasets and regression equations to compute selected streamflow statistics. With the cooperation of the Oklahoma Department of Transportation, StreamStats has been implemented for Oklahoma and is available at http://water.usgs.gov/osw/streamstats/. The Oklahoma StreamStats application covers 69 processed hydrologic units and most of the state of Oklahoma. Basin characteristics available for computation include contributing drainage area, contributing drainage area that is unregulated by Natural Resources Conservation Service floodwater retarding structures, mean-annual precipitation at the drainage-basin outlet for the period 1961-1990, 10-85 channel slope (slope between points located at 10 percent and 85 percent of the longest flow-path length upstream from the outlet), and percent impervious area. The Oklahoma StreamStats application interacts with the National Streamflow Statistics database, which contains the peak-flow regression equations in a previously published report. Fourteen peak-flow (flood) frequency statistics are available for computation in the Oklahoma StreamStats application. These statistics include the peak flow at 2-, 5-, 10-, 25-, 50-, 100-, and 500-year recurrence intervals for rural, unregulated streams; and the peak flow at 2-, 5-, 10-, 25-, 50-, 100-, and 500-year recurrence intervals for rural streams that are regulated by Natural Resources Conservation Service floodwater retarding structures. Basin characteristics and streamflow statistics cannot be computed for locations in playa basins (mostly in the Oklahoma Panhandle) and along main stems of the largest river systems in the state, namely the Arkansas, Canadian, Cimarron, Neosho, Red, and Verdigris Rivers, because parts of the drainage areas extend outside of the processed hydrologic units.

Distribution of invasive and native riparian woody plants across the western USA in relation to climate, river flow, floodplain geometry and patterns of introduction

USGS Publications Warehouse

Ryan McShane,; Daniel Auerbach,; Friedman, Jonathan M.; Auble, Gregor T.; Shafroth, Patrick B.; Michael Merigliano,; Scott, Michael L.; N. Leroy Poff,

2015-01-01

Management of riparian plant invasions across the landscape requires understanding the combined influence of climate, hydrology, geologic constraints and patterns of introduction. We measured abundance of nine riparian woody taxa at 456 stream gages across the western USA. We constructed conditional inference recursive binary partitioning models to discriminate the influence of eleven environmental variables on plant occurrence and abundance, focusing on the two most abundant non-native taxa, Tamarix spp. and Elaeagnus angustifolia, and their native competitor Populus deltoides. River reaches in this study were distributed along a composite gradient from cooler, wetter higher-elevation reaches with higher stream power and earlier snowmelt flood peaks to warmer, drier lower-elevation reaches with lower power and later peaks. Plant distributions were strongly related to climate, hydrologic and geomorphic factors, and introduction history. The strongest associations were with temperature and then precipitation. Among hydrologic and geomorphic variables, stream power, peak flow timing and 10-yr flood magnitude had stronger associations than did peak flow predictability, low-flow magnitude, mean annual flow and channel confinement. Nearby intentional planting of Elaeagnus was the best predictor of its occurrence, but planting of Tamarix was rare. Higher temperatures were associated with greater abundance of Tamarix relative to P. deltoides, and greater abundance of P. deltoides relative toElaeagnus. Populus deltoides abundance was more strongly related to peak flow timing than was that of Elaeagnus or Tamarix. Higher stream power and larger 10-yr floods were associated with greater abundance of P. deltoides and Tamarix relative to Elaeagnus. Therefore, increases in temperature could increase abundance of Tamarix and decrease that of Elaeagnus relative to P. deltoides, changes in peak flow timing caused by climate change or dam operations could increase abundance of both invasive taxa, and dam-induced reductions in flood peaks could increase abundance of Elaeagnus relative to Tamarix and P. deltoides.

Comparison of storm response of streams in small, unmined and valley-filled watersheds, 1999-2001, Ballard fork, West Virginia

USGS Publications Warehouse

Messinger, Terence

2003-01-01

During storms when rainfall intensity exceeded about 1 inch per hour, peak unit runoff from the Unnamed Tributary (surface-mined and filled) Watershed exceeded peak unit runoff from the Spring Branch (unmined) Watershed in the Ballard Fork Watershed in southern West Virginia. During most storms, those with intensity less than about 1 inch per hour, peak unit (area-normalized) flows were greater from the Spring Branch Watershed than the Unnamed Tributary Watershed. One storm that produced less than an inch of rain before flow from the previous storm had receded caused peak unit flow from the Unnamed Tributary Watershed to exceed peak unit flow from the Spring Branch Watershed. Peak unit flow was usually similar in Spring Branch and Ballard Fork. Peak unit flows are expected to decrease with increasing watershed size in homogeneous watersheds; drainage area and proportion of the three watersheds covered by valley fills are 0.19 square mile (mi?) and 44 percent for the Unnamed Tributary Watershed, 0.53 mi? and 0 percent for the Spring Branch Watershed, and 2.12 mi? and 12 percent for the Ballard Fork Watershed. Following all storms with sufficient rainfall intensity, about 0.25 inches per hour, the storm hydrograph from the Unnamed Tributary Watershed showed a double peak, as a sharp initial rise was followed by a decrease in flow and then a delayed secondary peak of water that had apparently flowed through the valley fill. Hortonian (excess overland) flow may be important in the Unnamed Tributary Watershed during intense storms, and may cause the initial peak on the rising arm of storm hydrographs; the water composing the initial peaks may be conveyed by drainage structures on the mine. Ballard Fork and Spring Branch had hydrographs with single peaks, typical of elsewhere in West Virginia. During all storms with 1-hour rainfall greater than 0.75 inches or 24-hour rainfall greater than 1.75 inches during which all stream gages recorded a complete record, the Unnamed Tributary yielded the most total unit flow. In three selected major storms, total unit flow from the Unnamed Tributary during recessions exceeded storm flow, and its total unit flow was greatest among the streams during all three recessions. Runoff patterns from the mined watershed are influenced by the compaction of soils on the mine, the apparent low maximum rate of infiltration into the valley fill compared to that in the unmined, forested watershed, storage of water in the valley fill, and the absence of interception from trees and leaf litter. No storms during this study produced 1-hour or 24-hour rainfall in excess of the 5-year return period, and streamflow during this study never exceeded a magnitude equivalent to the 1.5-year return period; relative peak unit flow among the three streams in this study could be different in larger storms. Rainfall-runoff relations on altered landscapes are site-specific, and aspects of mining and reclamation practice that affect storm response may vary among mines.

Flow Field and Acoustic Predictions for Three-Stream Jets

NASA Technical Reports Server (NTRS)

Simmons, Shaun Patrick; Henderson, Brenda S.; Khavaran, Abbas

2014-01-01

Computational fluid dynamics was used to analyze a three-stream nozzle parametric design space. The study varied bypass-to-core area ratio, tertiary-to-core area ratio and jet operating conditions. The flowfield solutions from the Reynolds-Averaged Navier-Stokes (RANS) code Overflow 2.2e were used to pre-screen experimental models for a future test in the Aero-Acoustic Propulsion Laboratory (AAPL) at the NASA Glenn Research Center (GRC). Flowfield solutions were considered in conjunction with the jet-noise-prediction code JeNo to screen the design concepts. A two-stream versus three-stream computation based on equal mass flow rates showed a reduction in peak turbulent kinetic energy (TKE) for the three-stream jet relative to that for the two-stream jet which resulted in reduced acoustic emission. Additional three-stream solutions were analyzed for salient flowfield features expected to impact farfield noise. As tertiary power settings were increased there was a corresponding near nozzle increase in shear rate that resulted in an increase in high frequency noise and a reduction in peak TKE. As tertiary-to-core area ratio was increased the tertiary potential core elongated and the peak TKE was reduced. The most noticeable change occurred as secondary-to-core area ratio was increased thickening the secondary potential core, elongating the primary potential core and reducing peak TKE. As forward flight Mach number was increased the jet plume region decreased and reduced peak TKE.

Flood reduction as an ecosystem service of constructed wetlands for combined sewer overflow

NASA Astrophysics Data System (ADS)

Rizzo, A.; Bresciani, R.; Masi, F.; Boano, F.; Revelli, R.; Ridolfi, L.

2018-05-01

Urban runoff negatively impacts the receiving streams and different solutions have been proposed in literature to limit the effect of urbanization on the water balance. These solutions suggest to manage urban runoff in order to switch from a post-development river hydrograph (high peak and short duration) back again to a pre-development hydrograph (low peak and high duration). Combined sewer overflows (CSOs) represent severe pollutant sources for receiving streams due to the combination of first flush of roads and sewers and black water conveyed by combined sewer systems. Constructed wetlands for CSO treatment (CSO-CWs) are adopted with increasing frequency for reducing pollutant inputs to streams. Moreover, these systems exhibit the characteristic to behave similarly to ponds, wetlands, and bioretention systems that provide flood mitigation by decreasing the intensity of peak flows. This work aims to show the additional ecosystem service provided by CSO-CWs in term of limitation of the hydraulic impact of CSO on stream hydrograph. A mathematical model is developed to simulate the hydraulic behavior of a real case study situated in Gorla Maggiore (Italy), which includes vertical flow subsurface beds (VF) as first stage and a free water surface bed (FWS) as second stage. The model simulates the unsaturated flow within VF and the accumulation of water on the top of VF and within FWS. Results show a satisfactory lamination performance of the system for both single and up to 5 consecutive flood events, with a peak flow reduction ranging from 52.7% to 95.4%. Withdrawn of flow rate from the river in order to cope with long dry period does not significantly affect the lamination performances. The considered CSO-CW exhibits an excellent lamination efficiency also during more intense floods events, with a peak flow reduction of 86.2% for a CSO event with return period of 10 years. The flow rate frequency density function determined by the CSO-CW is more shifted towards lower values compared to untreated CSOs. These results indicate that CSO-CWs work properly in terms of reduction of CSO urbanization impact on stream hydrology.

Regional flood-frequency relations for streams with many years of no flow

USGS Publications Warehouse

Hjalmarson, Hjalmar W.; Thomas, Blakemore E.; ,

1990-01-01

In the southwestern United States, flood-frequency relations for streams that drain small arid basins are difficult to estimate, largely because of the extreme temporal and spatial variability of floods and the many years of no flow. A method is proposed that is based on the station-year method. The new method produces regional flood-frequency relations using all available annual peak-discharge data. The prediction errors for the relations are directly assessed using randomly selected subsamples of the annual peak discharges.

Techniques for estimating peak-streamflow frequency for unregulated streams and streams regulated by small floodwater retarding structures in Oklahoma

USGS Publications Warehouse

Tortorelli, Robert L.

1997-01-01

Statewide regression equations for Oklahoma were determined for estimating peak discharge and flood frequency for selected recurrence intervals from 2 to 500 years for ungaged sites on natural unregulated streams. The most significant independent variables required to estimate peak-streamflow frequency for natural unregulated streams in Oklahoma are contributing drainage area, main-channel slope, and mean-annual precipitation. The regression equations are applicable for watersheds with drainage areas less than 2,510 square miles that are not affected by regulation from manmade works. Limitations on the use of the regression relations and the reliability of regression estimates for natural unregulated streams are discussed. Log-Pearson Type III analysis information, basin and climatic characteristics, and the peak-stream-flow frequency estimates for 251 gaging stations in Oklahoma and adjacent states are listed. Techniques are presented to make a peak-streamflow frequency estimate for gaged sites on natural unregulated streams and to use this result to estimate a nearby ungaged site on the same stream. For ungaged sites on urban streams, an adjustment of the statewide regression equations for natural unregulated streams can be used to estimate peak-streamflow frequency. For ungaged sites on streams regulated by small floodwater retarding structures, an adjustment of the statewide regression equations for natural unregulated streams can be used to estimate peak-streamflow frequency. The statewide regression equations are adjusted by substituting the drainage area below the floodwater retarding structures, or drainage area that represents the percentage of the unregulated basin, in the contributing drainage area parameter to obtain peak-streamflow frequency estimates.

Tracking the evolution of stream DOM source during storm events using end member mixing analysis based on DOM quality

NASA Astrophysics Data System (ADS)

Yang, Liyang; Chang, Soon-Woong; Shin, Hyun-Sang; Hur, Jin

2015-04-01

The source of river dissolved organic matter (DOM) during storm events has not been well constrained, which is critical in determining the quality and reactivity of DOM. This study assessed temporal changes in the contributions of four end members (weeds, leaf litter, soil, and groundwater), which exist in a small forested watershed (the Ehwa Brook, South Korea), to the stream DOM during two storm events, using end member mixing analysis (EMMA) based on spectroscopic properties of DOM. The instantaneous export fluxes of dissolved organic carbon (DOC), chromophoric DOM (CDOM), and fluorescent components were all enhanced during peak flows. The DOC concentration increased with the flow rate, while CDOM and humic-like fluorescent components were diluted around the peak flows. Leaf litter was dominant for the DOM source in event 2 with a higher rainfall, although there were temporal variations in the contributions of the four end members to the stream DOM for both events. The contribution of leaf litter peaked while that of deeper soils decreased to minima at peak flows. Our results demonstrated that EMMA based on DOM properties could be used to trace the DOM source, which is of fundamental importance for understanding the factors responsible for river DOM dynamics during storm events.

The efficacy of stream power and flow duration on geomorphic responses to catastrophic flooding

NASA Astrophysics Data System (ADS)

Magilligan, F. J.; Buraas, E. M.; Renshaw, C. E.

2015-01-01

Geomorphologists have long studied the impacts of extreme floods, yet the association between the magnitude of flow parameters (discharge, velocity, shear stress, or stream power) and resulting geomorphic effectiveness remains vague and non-deterministic. Attempts have been made to include flow duration and total expenditure of stream power, in combination with peak unit stream power, as important variables, but there has been minimal exploration of this hydraulic combination. Taking advantage of Tropical Storm Irene's rapid track through eastern Vermont (USA) in late summer 2011, this paper presents the array of geomorphic responses to a short duration (time to peak of < 8 h) but high magnitude flood that was the twentieth century flood of record for numerous watersheds. We present herein the geomorphic imprint of Tropical Storm Irene flooding within a larger context of fluvial theory concerning the role of, and trade-off between, the magnitude of energy expenditure during a flood and its duration. Focusing on a detailed field effort within the 187-km2 Saxtons River basin in southeastern VT, augmented by select sites along the adjacent lower gradient Williams River (291-km2), we elucidate (1) the geomorphic effects of a short duration flood in a humid, well-vegetated landscape; (2) the relationship between geomorphic response and (a) peak stream power, (b) total stream power, and (c) flow duration of stream power above a critical threshold; and (3) the spatial variation of geomorphic effects relative to reach-scale geologic and geomorphic controls. Flooding associated with Tropical Storm Irene ranged from the 1000 year recurrence interval (RI) flood (based on Weibull flood frequency analysis) to the 300 year RI flood (log Pearson Type III). Discharges spawned a peak unit stream power of 712 W/m2 (Saxtons River) and 361 W/m2 (Williams River), with total energy expenditure throughout the event of ~ 16,000 × 103 and 15,000 × 103 J, respectively. For the Saxtons River, channel widening was spatially infrequent and limited in magnitude; however, other geomorphic effects were profound (1) the entrainment, transport, and deposition of extremely coarse material; (2) stripping of floodplain surfaces; (3) channel avulsions and incision into Pleistocene-aged material; and (4) deposition of coarse material across floodplains. Based on our extensive field data and hydrologic/hydraulic analyses, we contend that short duration, high energy flows can have profound sedimentological effects but have limited erosive, channel widening impacts. Gravel entrainment and deposition of a catastrophic nature can certainly occur under these flow regimes, but the impacts of these extreme flows on channel geometry may have limited expression.

A Streaming Language Implementation of the Discontinuous Galerkin Method

NASA Technical Reports Server (NTRS)

Barth, Timothy; Knight, Timothy

2005-01-01

We present a Brook streaming language implementation of the 3-D discontinuous Galerkin method for compressible fluid flow on tetrahedral meshes. Efficient implementation of the discontinuous Galerkin method using the streaming model of computation introduces several algorithmic design challenges. Using a cycle-accurate simulator, performance characteristics have been obtained for the Stanford Merrimac stream processor. The current Merrimac design achieves 128 Gflops per chip and the desktop board is populated with 16 chips yielding a peak performance of 2 Teraflops. Total parts cost for the desktop board is less than $20K. Current cycle-accurate simulations for discretizations of the 3-D compressible flow equations yield approximately 40-50% of the peak performance of the Merrimac streaming processor chip. Ongoing work includes the assessment of the performance of the same algorithm on the 2 Teraflop desktop board with a target goal of achieving 1 Teraflop performance.

Comparison of Peak-Flow Estimation Methods for Small Drainage Basins in Maine

USGS Publications Warehouse

Hodgkins, Glenn A.; Hebson, Charles; Lombard, Pamela J.; Mann, Alexander

2007-01-01

Understanding the accuracy of commonly used methods for estimating peak streamflows is important because the designs of bridges, culverts, and other river structures are based on these flows. Different methods for estimating peak streamflows were analyzed for small drainage basins in Maine. For the smallest basins, with drainage areas of 0.2 to 1.0 square mile, nine peak streamflows from actual rainfall events at four crest-stage gaging stations were modeled by the Rational Method and the Natural Resource Conservation Service TR-20 method and compared to observed peak flows. The Rational Method had a root mean square error (RMSE) of -69.7 to 230 percent (which means that approximately two thirds of the modeled flows were within -69.7 to 230 percent of the observed flows). The TR-20 method had an RMSE of -98.0 to 5,010 percent. Both the Rational Method and TR-20 underestimated the observed flows in most cases. For small basins, with drainage areas of 1.0 to 10 square miles, modeled peak flows were compared to observed statistical peak flows with return periods of 2, 50, and 100 years for 17 streams in Maine and adjoining parts of New Hampshire. Peak flows were modeled by the Rational Method, the Natural Resources Conservation Service TR-20 method, U.S. Geological Survey regression equations, and the Probabilistic Rational Method. The regression equations were the most accurate method of computing peak flows in Maine for streams with drainage areas of 1.0 to 10 square miles with an RMSE of -34.3 to 52.2 percent for 50-year peak flows. The Probabilistic Rational Method was the next most accurate method (-38.5 to 62.6 percent). The Rational Method (-56.1 to 128 percent) and particularly the TR-20 method (-76.4 to 323 percent) had much larger errors. Both the TR-20 and regression methods had similar numbers of underpredictions and overpredictions. The Rational Method overpredicted most peak flows and the Probabilistic Rational Method tended to overpredict peak flows from the smaller (less than 5 square miles) drainage basins and underpredict peak flows from larger drainage basins. The results of this study are consistent with the most comprehensive analysis of observed and modeled peak streamflows in the United States, which analyzed statistical peak flows from 70 drainage basins in the Midwest and the Northwest.

Differential behaviour of Escherichia coli and Campylobacter spp. in a stream draining dairy pasture.

PubMed

Stott, Rebecca; Davies-Colley, Robert; Nagels, John; Donnison, Andrea; Ross, Colleen; Muirhead, Richard

2011-03-01

The faecal indicator bacterium Escherichia coli and thermotolerant Campylobacter spp., which are potentially pathogenic, were investigated in the Toenepi Stream draining a pastoral catchment dominated by dairying. Bacteria concentrations were monitored routinely at fortnightly intervals over 12 months and intensively during storm events to compare the transport dynamics of bacterial indicator and pathogen under varying hydro-meteorological conditions. Routine monitoring indicated median concentrations of 345 E. coli MPN 100 ml(-1) and relatively low concentrations of 2.3 Campylobacter MPN 100 ml(-1). The bacterial flux was three orders of magnitude greater under elevated stream flow compared with base-flow. E. coli peak concentrations occurred very close to the turbidity peak and consistently ahead of the Campylobacter spp. peak (which was close to the hydrograph peak). We postulate that, under flood conditions, the E. coli peak reflects the entrainment and mobilisation of in-stream stores on the flood wave front. In contrast, Campylobacter spp. are derived from wash-in from land stores upstream and have travelled at the mean water velocity which is slower than the speed of the flood wave. Our findings of different dynamics for E. coli and Campylobacter spp. suggest that mitigation to reduce faecal microbial impacts from farms will need to take account of these differences.

Emergence cues of a mayfly in a high-altitude stream ecosystem: potential response to climate change.

PubMed

Harper, Matthew P; Peckarsky, Barbara L

2006-04-01

To understand the consequences of human accelerated environmental change, it is important to document the effects on natural populations of an increasing frequency of extreme climatic events. In stream ecosystems, recent climate change has resulted in extreme variation in both thermal and hydrological regimes. From 2001 to 2004, a severe drought in western United States corresponded with earlier emergence of the adult stage of the high-altitude stream mayfly, Baetis bicaudatus. Using a long-term database from a western Colorado stream, the peak emergence date of this mayfly population was predicted by both the magnitude and date of peak stream flow, and by the mean daily water temperature, suggesting that Baetis may respond to declining stream flow or increasing water temperature as proximate cues for early metamorphosis. However, in a one-year survey of multiple streams from the same drainage basin, only water temperature predicted spatial variation in the onset of emergence of this mayfly. To decouple the effects of temperature and flow, we separately manipulated these factors in flow-through microcosms and measured the timing of B. bicaudatus metamorphosis to the adult stage. Mayflies emerged sooner in a warmed-water treatment than an ambient-water treatment; but reducing flow did not accelerate the onset of mayfly emergence. Nonetheless, using warming temperatures to cue metamorphosis enables mayflies to time their emergence during the descending limb of the hydrograph when oviposition sites (protruding rocks) are becoming available. We speculate that large-scale climate changes involving warming and stream drying could cause significant shifts in the timing of mayfly metamorphosis, thereby having negative effects on populations that play an important role in stream ecosystems.

Hillslope response to sprinkling and natural rainfall using velocity and celerity estimates in a slate-bedrock catchment

NASA Astrophysics Data System (ADS)

Scaini, Anna; Hissler, Christophe; Fenicia, Fabrizio; Juilleret, Jérôme; Iffly, Jean François; Pfister, Laurent; Beven, Keith

2018-03-01

Subsurface flow is often recognized as a dominant runoff generation process. However, observing subsurface properties, and understanding how they control flow pathways, remains challenging. This paper investigates how surface slope and bedrock cleavage control subsurface flow pathways in a slate bedrock headwater catchment in Luxembourg, characterised by a double-peak streamflow response. We use a range of experimental techniques, including field observations of soil and bedrock characteristics, and a sprinkling experiment at a site located 40 m upslope from the stream channel. The sprinkling experiment uses Br- as a tracer, which is measured at a well downslope from the plot and at various locations along the stream, together with well and stream hydrometric responses. The sprinkling experiment is used to estimate velocities and celerities, which in turn are used to infer flow pathways. Our results indicate that the single or first peak of double-peak events is rainfall-driven (controlled by rainfall) while the second peak is storage-driven (controlled by storage). The comparison between velocity and celerity estimates suggests a fast flowpath component connecting the hillslope to the stream, but velocity information was too scarce to fully support such a hypothesis. In addition, different estimates of celerities suggest a seasonal influence of both rainfall intensity rate and residual water storage on the celerity responses at the hillslope scale. At the catchment outlet, the estimated of the total mass of Br- recovered in the stream was about 2.5% of the application. Further downstream, the estimate mass of Br- was about 4.0% of the application. This demonstrates that flowpaths do not appear to align with the slope gradient. In contrast, they appear to follow the strike of the bedrock cleavage. Our results have expanded our understanding of the importance of the subsurface, in particular the underlying bedrock systems, and the importance of cleavage orientation, as well as topography, in controlling subsurface flow direction in this catchment.

Regional Curves for Bankfull Channel Characteristics in the Appalachian Plateaus, West Virginia

USGS Publications Warehouse

Messinger, Terence

2009-01-01

Streams in the Appalachian Plateaus Physiographic Province in West Virginia were classified as a single region on the basis of bankfull characteristics. Regression lines for annual peak flow and drainage area measured at streamgages in the study area at recurrence intervals between 1.2 and 1.7 years fell within the 99-percent confidence interval of the regression line for bankfull flow. Channel characteristics were intermediate among those from surrounding states and regions where comparable studies have been done. The stream reaches that were surveyed were selected for apparent stability, and to represent gradients of drainage area, elevation, and mean annual precipitation. Profiles of high-water marks left by bankfull and near-bankfull peaks were surveyed, either as part of slope-area flow measurements at ungaged reaches, or to transfer known flow information to cross sections for gaged reaches. The slope-area measurements made it possible to include ungaged sites in the study, but still relate bankfull dimensions to peak flow and frequency.

IOD and ENSO impacts on the extreme stream-flows of Citarum river in Indonesia

NASA Astrophysics Data System (ADS)

Sahu, Netrananda; Behera, Swadhin K.; Yamashiki, Yosuke; Takara, Kaoru; Yamagata, Toshio

2012-10-01

Extreme stream-flow events of Citarum River are derived from the daily stream-flows at the Nanjung gauge station. Those events are identified based on their persistently extreme flows for 6 or more days during boreal fall when the seasonal mean stream-flow starts peaking-up from the lowest seasonal flows of June-August. Most of the extreme events of high-streamflows were related to La Niña conditions of tropical Pacific. A few of them were also associated with the negative phases of IOD and the newly identified El Niño Modoki. Unlike the cases of extreme high streamflows, extreme low streamflow events are seen to be associated with the positive IODs. Nevertheless, it was also found that the low-stream-flow events related to positive IOD events were also associated with El Niño events except for one independent event of 1977. Because the occurrence season coincides the peak season of IOD, not only the picked extreme events are seen to fall under the IOD seasons but also there exists a statistically significant correlation of 0.51 between the seasonal IOD index and the seasonal streamflows. There also exists a significant lag correlation when IOD of June-August season leads the streamflows of September-November. A significant but lower correlation coefficient (0.39) is also found between the seasonal streamflow and El Niño for September-November season only.

Hydrologic response of streams restored with check dams in the Chiricahua Mountains, Arizona

USGS Publications Warehouse

Norman, Laura M.; Brinkerhoff, Fletcher C.; Gwilliam, Evan; Guertin, D. Phillip; Callegary, James B.; Goodrich, David C.; Nagler, Pamela L.; Gray, Floyd

2016-01-01

In this study, hydrological processes are evaluated to determine impacts of stream restoration in the West Turkey Creek, Chiricahua Mountains, southeast Arizona, during a summer-monsoon season (June–October of 2013). A paired-watershed approach was used to analyze the effectiveness of check dams to mitigate high flows and impact long-term maintenance of hydrologic function. One watershed had been extensively altered by the installation of numerous small check dams over the past 30 years, and the other was untreated (control). We modified and installed a new stream-gauging mechanism developed for remote areas, to compare the water balance and calculate rainfall–runoff ratios. Results show that even 30 years after installation, most of the check dams were still functional. The watershed treated with check dams has a lower runoff response to precipitation compared with the untreated, most notably in measurements of peak flow. Concerns that downstream flows would be reduced in the treated watershed, due to storage of water behind upstream check dams, were not realized; instead, flow volumes were actually higher overall in the treated stream, even though peak flows were dampened. We surmise that check dams are a useful management tool for reducing flow velocities associated with erosion and degradation and posit they can increase baseflow in aridlands.

Peak-flow frequency estimates through 1994 for gaged streams in South Dakota

USGS Publications Warehouse

Burr, M.J.; Korkow, K.L.

1996-01-01

Annual peak-flow data are listed for 250 continuous-record and crest-stage gaging stations in South Dakota. Peak-flow frequency estimates for selected recurrence intervals ranging from 2 to 500 years are given for 234 of these 250 stations. The log-Pearson Type III procedure was used to compute the frequency relations for the 234 stations, which in 1994 included 105 active and 129 inactive stations. The log-Pearson Type III procedure is recommended by the Hydrology Subcommittee of the Interagency Advisory Committee on Water Data, 1982, "Guidelines for Determining Flood Flow Frequency."No peak-flow frequency estimates are given for 16 of the 250 stations because: (1) of extreme variability in data set; (2) more than 20 percent of years had no flow; (3) annual peak flows represent large outflow from a spring; (4) of insufficient peak-flow record subsequent to reservoir regulation; and (5) peak-flow records were combined with records from nearby stations.

Peak-flow frequency and extreme flood potential for streams in the vicinity of the Highland Lakes, central Texas

USGS Publications Warehouse

Asquith, William H.; Slade, R.M.; Lanning-Rush, Jennifer

1996-01-01

The Highland Lakes on the Colorado River are in an area periodically threatened by large storms and floods. Many storms exceeding 10 inches (in.) in depth have been documented in the area, including some with depths approaching 40 in. These storms typically produce large peak discharges that often threaten lives and property. The storms sometimes occur with little warning. Steep stream slopes and thin soils characteristic of the area often cause large peak discharges and rapid movement of floods through watersheds. A procedure to predict the discharge associated with large floods is needed for the area so that appropriate peak discharges can be used in the design of flood plains, bridges, and other structures.The U.S. Geological Survey (USGS), in cooperation with the Lower Colorado River Authority (LCRA), studied flood peaks for streams in the vicinity of the Highland Lakes of central Texas. The Highland Lakes are a series of reservoirs constructed on the Colorado River. The chain of lakes (and year each was completed) comprises Lake Buchanan (1937), Inks Lake (1938), Lake Lyndon B. Johnson (1950), Lake Marble Falls (1951), Lake Travis (1942), and lake Austin (1890). The study area (fig. 1), which includes all or parts of 21 counties in the vicinity of the Highland Lakes, was selected because most streams in the area have flood characteristics similar to streams entering the Highland Lakes. The entire study area is in a region subject to large storms.The purpose of this report is to present (1) peak-flow frequency data for stations and equations to estimate peak-flow frequency for large streams with natural drainage basins in the vicinity of the Highland Lakes, and (2) a technique to estimate the extreme flood peak discharges for the large streams in the vicinity of the Highland Lakes. Peak-flow frequency in this report refers to the peak discharges for recurrence intervals of 2,5, 10,25,50, and 100 years. A large stream is defined as having a contributing drainage area of at least0.5 square mile (mi’); and a natural drainage basin has less than 10 percent impervious cover and less than 10 percent of its drainage area controlled by reservoirs.The mean annual precipitation in the study area for 1951–80 ranges from about 20 in, in western Kimble County to about 34 in. at the eastern edge of Williamson County (Riggio and others, 1987, p. 23). Many large storms and catastrophic floods have occurred along or in the adjacent area west of the Balcones escarpment (fig. 1) (Dalrymple and others, 1939, Breeding and Dalrymple, 1944; Breeding and Montgomery, 1954; Schroeder and others, 1979; Caran and Baker, 1986; Slade, 1986; and Hejl and others, 1996). About a dozen storms with precipitation depths exceeding 15 in. in a few days or less have been documented in this area during the past 60 years. Some of these storms have produced world-record precipitation depths for durations less than 48 hours. The documentation for these and for other large storms indicates that they are not uniformly distributed temporally or spatially; therefore, the recurrence intervals for such storms cannot be verified (Slade, 1986, p. 17). These large storms can cause flood peaks that would exceed those that can be predicted accurately by analyses of available precipitation or flood data.The peak-flow frequency was estimated for each of 55 qualified stations in the study area (table 1) following guidelines established by the Interagency Advisory Committee on Water Data (1982). Qualified streamflow-gaging stations for the study area are those with at least 8 years of data from natural drainage basins (sites 1–55, fig. 1). Equations to estimate peak-flow frequency for large streams with natural drainage basins in the vicinity of the Highland Lakes were developed. These equations were developed from selected stations on the basis of the relation between peak-flow frequency and basin characteristics for each station. The entire period of systematic record (through 1993) was used in the frequency analyses for each qualified station except for stations at which streamflow was regulated during part of the record. These stations are Leon River near Belton (site 1): Lampasas River near Youngsport (site 5); North Fork San Gabriel River near Georgetown (site 6); San Gabriel River at Laneport (site 12); Brady Creek at Brady (site 16); San Saba River at San Saba (site 18); Rebecca Creek near Spring Branch (site 51); and Cibolo Creek near Boerne (site 54). One or more reservoirs were completed in the basin of each of these stations during the period of systematic record. These reservoirs caused the annual peak discharges to become regulated. The annual peak discharges for 1994 and 1995 at Sandy Creek near Kingsland (site 28) were used to include data associated with extreme flooding that occurred in 1995.The extreme flood potential in the study area was investigated using an "envelope" or "extreme flood potential" curve. This curve is based on the relation between the contributing drainage area and (1) the maximum peak discharge of record for each qualified station (table 1); (2) substantial peak discharges documented for 84 sites without stations (sites 56–139, fig. 1, table 2); and (3) 100-year peak discharges from peak-flow frequency for stations (table 1). Peak discharges estimated from this curve represent the extreme flood potential for the study area.

Fire, flow and dynamic equilibrium in stream macroinvertebrate communities

USGS Publications Warehouse

Arkle, R.S.; Pilliod, D.S.; Strickler, K.

2010-01-01

The complex effects of disturbances on ecological communities can be further complicated by subsequent perturbations within an ecosystem. We investigated how wildfire interacts with annual variations in peak streamflow to affect the stability of stream macroinvertebrate communities in a central Idaho wilderness, USA. We conducted a 4-year retrospective analysis of unburned (n = 7) and burned (n = 6) catchments, using changes in reflectance values (??NBR) from satellite imagery to quantify the percentage of each catchment's riparian and upland vegetation that burned at high and low severity. For this wildland fire complex, increasing riparian burn severity and extent were associated with greater year-to-year variation, rather than a perennial increase, in sediment loads, organic debris, large woody debris (LWD) and undercut bank structure. Temporal changes in these variables were correlated with yearly peak flow in burned catchments but not in unburned reference catchments, indicating that an interaction between fire and flow can result in decreased habitat stability in burned catchments. Streams in more severely burned catchments exhibited increasingly dynamic macroinvertebrate communities and did not show increased similarity to reference streams over time. Annual variability in macroinvertebrates was attributed, predominantly, to the changing influence of sediment, LWD, riparian cover and organic debris, as quantities of these habitat components fluctuated annually depending on burn severity and annual peak streamflows. These analyses suggest that interactions among fire, flow and stream habitat may increase inter-annual habitat variability and macroinvertebrate community dynamics for a duration approaching the length of the historic fire return interval of the study area. ?? 2009 Blackwell Publishing Ltd.

Geomorphic, flood, and groundwater-flow characteristics of Bayfield Peninsula streams, Wisconsin, and implications for brook-trout habitat

USGS Publications Warehouse

Fitzpatrick, Faith A.; Peppler, Marie C.; Saad, David A.; Pratt, Dennis M.; Lenz, Bernard N.

2015-01-01

Available brook-trout habitat is dependent on the locations of groundwater upwellings, the sizes of flood peaks, and sediment loads. Management practices that focus on reducing or slowing runoff from upland areas and increasing channel roughness have potential to reduce flood peaks, erosion, and sedimentation and improve brook-trout habitat in all Bayfield Peninsula streams.

Impacts of logging on storm peak flows, flow volumes and suspended sediment loads in Caspar Creek, California

Treesearch

Jack Lewis; Sylvia R. Mori; Elizabeth T. Keppeler; Robert R. Ziemer

2001-01-01

Abstract - Models are fit to 11 years of storm peak flows, flow volumes, and suspended sediment loads on a network of 14 stream gaging stations in the North Fork Caspar Creek, a 473-ha coastal watershed bearing a second-growth forest of redwood and Douglas-fir. For the first 4 years of monitoring, the watershed was in a relatively undisturbed state, having last been...

Peak flow regression equations For small, ungaged streams in Maine: Comparing map-based to field-based variables

USGS Publications Warehouse

Lombard, Pamela J.; Hodgkins, Glenn A.

2015-01-01

Regression equations to estimate peak streamflows with 1- to 500-year recurrence intervals (annual exceedance probabilities from 99 to 0.2 percent, respectively) were developed for small, ungaged streams in Maine. Equations presented here are the best available equations for estimating peak flows at ungaged basins in Maine with drainage areas from 0.3 to 12 square miles (mi2). Previously developed equations continue to be the best available equations for estimating peak flows for basin areas greater than 12 mi2. New equations presented here are based on streamflow records at 40 U.S. Geological Survey streamgages with a minimum of 10 years of recorded peak flows between 1963 and 2012. Ordinary least-squares regression techniques were used to determine the best explanatory variables for the regression equations. Traditional map-based explanatory variables were compared to variables requiring field measurements. Two field-based variables—culvert rust lines and bankfull channel widths—either were not commonly found or did not explain enough of the variability in the peak flows to warrant inclusion in the equations. The best explanatory variables were drainage area and percent basin wetlands; values for these variables were determined with a geographic information system. Generalized least-squares regression was used with these two variables to determine the equation coefficients and estimates of accuracy for the final equations.

Techniques for estimating magnitude and frequency of peak flows for Pennsylvania streams

USGS Publications Warehouse

Stuckey, Marla H.; Reed, Lloyd A.

2000-01-01

Regression equations for estimating the magnitude and frequency of floods on ungaged streams in Pennsylvania with drainage areas less that 2,000 square miles were developed on the basis of peak-flow data collected at 313 streamflow-gaging stations. All streamflow-gaging stations used in the development of the equations had 10 or more years of record and include active and discontinued continuous-record and crest-stage partial-record streamflow-gaging stations. Regional regression equations were developed for flood flows expected every 10, 25, 50, 100, and 500 years by the use of a weighted multiple linear regression model.The State was divided into two regions. The largest region, Region A, encompasses about 78 percent of Pennsylvania. The smaller region, Region B, includes only the northwestern part of the State. Basin characteristics used in the regression equations for Region A are drainage area, percentage of forest cover, percentage of urban development, percentage of basin underlain by carbonate bedrock, and percentage of basin controlled by lakes, swamps, and reservoirs. Basin characteristics used in the regression equations for Region B are drainage area and percentage of basin controlled by lakes, swamps, and reservoirs. The coefficient of determination (R2) values for the five flood-frequency equations for Region A range from 0.93 to 0.82, and for Region B, the range is from 0.96 to 0.89.While the regression equations can be used to predict the magnitude and frequency of peak flows for most streams in the State, they should not be used for streams with drainage areas greater than 2,000 square miles or less than 1.5 square miles, for streams that drain extensively mined areas, or for stream reaches immediately below flood-control reservoirs. In addition, the equations presented for Region B should not be used if the stream drains a basin with more than 5 percent urban development.

Coupled hydrological and biogeochemical processes controlling variability of nitrogen species in streamflow during autumn in an upland forest

USGS Publications Warehouse

Sebestyen, Stephen D.; Shanley, James B.; Boyer, Elizabeth W.; Kendall, Carol; Doctor, Daniel H.

2014-01-01

Autumn is a season of dynamic change in forest streams of the northeastern United States due to effects of leaf fall on both hydrology and biogeochemistry. Few studies have explored how interactions of biogeochemical transformations, various nitrogen sources, and catchment flow paths affect stream nitrogen variation during autumn. To provide more information on this critical period, we studied (1) the timing, duration, and magnitude of changes to stream nitrate, dissolved organic nitrogen (DON), and ammonium concentrations; (2) changes in nitrate sources and cycling; and (3) source areas of the landscape that most influence stream nitrogen. We collected samples at higher temporal resolution for a longer duration than typical studies of stream nitrogen during autumn. This sampling scheme encompassed the patterns and extremes that occurred during base flow and stormflow events of autumn. Base flow nitrate concentrations decreased by an order of magnitude from 5.4 to 0.7 µmol L−1 during the week when most leaves fell from deciduous trees. Changes to rates of biogeochemical transformations during autumn base flow explained the low nitrate concentrations; in-stream transformations retained up to 72% of the nitrate that entered a stream reach. A decrease of in-stream nitrification coupled with heterotrophic nitrate cycling were primary factors in the seasonal nitrate decline. The period of low nitrate concentrations ended with a storm event in which stream nitrate concentrations increased by 25-fold. In the ensuing weeks, peak stormflow nitrate concentrations progressively decreased over closely spaced, yet similarly sized events. Most stormflow nitrate originated from nitrification in near-stream areas with occasional, large inputs of unprocessed atmospheric nitrate, which has rarely been reported for nonsnowmelt events. A maximum input of 33% unprocessed atmospheric nitrate to the stream occurred during one event. Large inputs of unprocessed atmospheric nitrate show direct and rapid effects on forest streams that may be widespread, although undocumented, throughout nitrogen-polluted temperate forests. In contrast to a week-long nitrate decline during peak autumn litterfall, base flow DON concentrations increased after leaf fall and remained high for 2 months. Dissolved organic nitrogen was hydrologically flushed to the stream from riparian soils during stormflow. In contrast to distinct seasonal changes in base flow nitrate and DON concentrations, ammonium concentrations were typically at or below the detection limit, similar to the rest of the year. Our findings reveal couplings among catchment flow paths, nutrient sources, and transformations that control seasonal extremes of stream nitrogen in forested landscapes.

Contrasting dissolved organic carbon dynamics at two forested catchments interpreted from high-frequency optical sensor measurements

NASA Astrophysics Data System (ADS)

Saraceno, J.; Shanley, J. B.

2015-12-01

Stream dissolved organic carbon (DOC) concentrations can change rapidly during high-flow events. The timing and magnitude of these changes relative to the event hydrograph can yield insights about possible DOC sources its flow paths to the stream. In situ fluorescent dissolved organic matter (FDOM) sensors that generate high-frequency observations enable detailed examination of high-flow DOC- discharge hysteresis. In this presentation, we interpret high-flow DOC dynamics at two of the five U.S. Geological Survey (USGS) Water, Energy, and Biogeochemical Budgets (WEBB) sites - Panola Mountain, Georgia and Sleepers River, Vermont. Based on laboratory analyses of weekly and event grab samples, both USGS WEBB sites had a similar DOC ranges: from ~1 milligrams per liter (mg/L) at base flow to ~11-15 mg/L during the largest events. A curvilinear relationship between DOC and FDOM (corrected for temperature and turbidity interferences) was used to model a continuous time series of DOC. At the Sleepers River site, DOC showed a seasonal pattern of increasing DOC response; from fairly subdued during spring snowmelt, to a maximum during autumn leaf-fall. The DOC response to discharge showed a consistent clockwise hysteresis (DOC peak, lagged discharge peak). At the Panola Mountain site, maximum event DOC response was lower during wet conditions in the winter and spring. Hysteresis was less expressed at Panola Mountain relative to Sleepers River and displayed both clockwise and counterclockwise patterns, which were dependent on antecedent moisture conditions. The greater synchrony of DOC and discharge peaks at Panola Mountain suggests that DOC sources are closer to the stream and (or) move to the stream more quickly, than at Sleepers River.

Magnitude and Frequency of Floods on Nontidal Streams in Delaware

USGS Publications Warehouse

Ries, Kernell G.; Dillow, Jonathan J.A.

2006-01-01

Reliable estimates of the magnitude and frequency of annual peak flows are required for the economical and safe design of transportation and water-conveyance structures. This report, done in cooperation with the Delaware Department of Transportation (DelDOT) and the Delaware Geological Survey (DGS), presents methods for estimating the magnitude and frequency of floods on nontidal streams in Delaware at locations where streamgaging stations monitor streamflow continuously and at ungaged sites. Methods are presented for estimating the magnitude of floods for return frequencies ranging from 2 through 500 years. These methods are applicable to watersheds exhibiting a full range of urban development conditions. The report also describes StreamStats, a web application that makes it easy to obtain flood-frequency estimates for user-selected locations on Delaware streams. Flood-frequency estimates for ungaged sites are obtained through a process known as regionalization, using statistical regression analysis, where information determined for a group of streamgaging stations within a region forms the basis for estimates for ungaged sites within the region. One hundred and sixteen streamgaging stations in and near Delaware with at least 10 years of non-regulated annual peak-flow data available were used in the regional analysis. Estimates for gaged sites are obtained by combining the station peak-flow statistics (mean, standard deviation, and skew) and peak-flow estimates with regional estimates of skew and flood-frequency magnitudes. Example flood-frequency estimate calculations using the methods presented in the report are given for: (1) ungaged sites, (2) gaged locations, (3) sites upstream or downstream from a gaged location, and (4) sites between gaged locations. Regional regression equations applicable to ungaged sites in the Piedmont and Coastal Plain Physiographic Provinces of Delaware are presented. The equations incorporate drainage area, forest cover, impervious area, basin storage, housing density, soil type A, and mean basin slope as explanatory variables, and have average standard errors of prediction ranging from 28 to 72 percent. Additional regression equations that incorporate drainage area and housing density as explanatory variables are presented for use in defining the effects of urbanization on peak-flow estimates throughout Delaware for the 2-year through 500-year recurrence intervals, along with suggestions for their appropriate use in predicting development-affected peak flows. Additional topics associated with the analyses performed during the study are also discussed, including: (1) the availability and description of more than 30 basin and climatic characteristics considered during the development of the regional regression equations; (2) the treatment of increasing trends in the annual peak-flow series identified at 18 gaged sites, with respect to their relations with maximum 24-hour precipitation and housing density, and their use in the regional analysis; (3) calculation of the 90-percent confidence interval associated with peak-flow estimates from the regional regression equations; and (4) a comparison of flood-frequency estimates at gages used in a previous study, highlighting the effects of various improved analytical techniques.

Regional regression equations to estimate peak-flow frequency at sites in North Dakota using data through 2009

USGS Publications Warehouse

Williams-Sether, Tara

2015-08-06

Annual peak-flow frequency data from 231 U.S. Geological Survey streamflow-gaging stations in North Dakota and parts of Montana, South Dakota, and Minnesota, with 10 or more years of unregulated peak-flow record, were used to develop regional regression equations for exceedance probabilities of 0.5, 0.20, 0.10, 0.04, 0.02, 0.01, and 0.002 using generalized least-squares techniques. Updated peak-flow frequency estimates for 262 streamflow-gaging stations were developed using data through 2009 and log-Pearson Type III procedures outlined by the Hydrology Subcommittee of the Interagency Advisory Committee on Water Data. An average generalized skew coefficient was determined for three hydrologic zones in North Dakota. A StreamStats web application was developed to estimate basin characteristics for the regional regression equation analysis. Methods for estimating a weighted peak-flow frequency for gaged sites and ungaged sites are presented.

Concentration-discharge relationships in headwater streams of the Sierra Nevada, California

NASA Astrophysics Data System (ADS)

Hunsaker, Carolyn T.; Johnson, Dale W.

2017-09-01

We examined stream water concentration-discharge relationships for eight small, forest watersheds ranging in elevation from 1485 to 2465 m in the southern Sierra Nevada. These headwater streams revealed nearly chemostatic behavior by current definitions for K+, Ca2+, Mg2+, Na+, Cl-, and SO42- in most cases but not for NH4+, NO3-, or ortho-P. The latter ions were somewhat enriched during high flows. All ions studied showed a dilution process at lower flows (<50 L s-1) with the concentration-discharge relationship being more chemostatic at higher flows. While previous studies in the Sierra Nevada have reported peak concentrations of NH4+, NO3-, and SO42- during snowmelt, the headwater systems of the Kings River Experimental Watersheds experience peak concentrations of these ions during the fall rains after the dry summer. These forested watersheds span the rain-snow transition zone, are 49-228 ha in size, and have soils derived from granite. A statistically significant relationship between soils and stream water concentrations for ortho-P, Ca2+, and Na+ strongly suggests that soil chemistry has a major influence on stream water chemistry. Factors controlling stream water NH4+, NO3-, and SO42- concentrations are less clear, but one possible source of spikes in these ions during storm events is input from O-horizon runoff where high concentrations were measured. Overall, stream water concentration-discharge relationships for these Sierran watersheds are similar to those found in other watershed systems (nearly chemostatic); however, the dominant processes controlling these relationships are probably localized because of different watershed characteristics like soil chemistry, vegetation cover, hydrologic flow paths, and weather patterns.

Role of surface-water and groundwater interactions on projected summertime streamflow in snow dominated regions : An integrated modeling approach

USGS Publications Warehouse

Huntington, Justin L.; Niswonger, Richard G.

2012-01-01

Previous studies indicate predominantly increasing trends in precipitation across the Western United States, while at the same time, historical streamflow records indicate decreasing summertime streamflow and 25th percentile annual flows. These opposing trends could be viewed as paradoxical, given that several studies suggest that increased annual precipitation will equate to increased annual groundwater recharge, and therefore increased summertime flow. To gain insight on mechanisms behind these potential changes, we rely on a calibrated, integrated surface and groundwater model to simulate climate impacts on surface water/groundwater interactions using 12 general circulation model projections of temperature and precipitation from 2010 to 2100, and evaluate the interplay between snowmelt timing and other hydrologic variables, including streamflow, groundwater recharge, storage, groundwater discharge, and evapotranspiration. Hydrologic simulations show that the timing of peak groundwater discharge to the stream is inversely correlated to snowmelt runoff and groundwater recharge due to the bank storage effect and reversal of hydraulic gradients between the stream and underlying groundwater. That is, groundwater flow to streams peaks following the decrease in stream depth caused by snowmelt recession, and the shift in snowmelt causes a corresponding shift in groundwater discharge to streams. Our results show that groundwater discharge to streams is depleted during the summer due to earlier drainage of shallow aquifers adjacent to streams even if projected annual precipitation and groundwater recharge increases. These projected changes in surface water/groundwater interactions result in more than a 30% decrease in the projected ensemble summertime streamflow. Our findings clarify causality of observed decreasing summertime flow, highlight important aspects of potential climate change impacts on groundwater resources, and underscore the need for integrated hydrologic models in climate change studies.

Flow behaviour, suspended sediment transport and transmission losses in a small (sub-bank-full) flow event in an Australian desert stream

NASA Astrophysics Data System (ADS)

Dunkerley, David; Brown, Kate

1999-08-01

The behaviour of a discrete sub-bank-full flow event in a small desert stream in western NSW, Australia, is analysed from direct observation and sediment sampling during the flow event and from later channel surveys. The flow event, the result of an isolated afternoon thunderstorm, had a peak discharge of 9 m3/s at an upstream station. Transmission loss totally consumed the flow over the following 7·6 km. Suspended sediment concentration was highest at the flow front (not the discharge peak) and declined linearly with the log of time since passage of the flow front, regardless of discharge variation. The transmission loss responsible for the waning and eventual cessation of flow occurred at a mean rate of 13.2% per km. This is quite rapid, and is more than twice the corresponding figure for bank-full flows estimated by Dunkerley (1992) on the same stream system. It is proposed that transmission losses in ephemeral streams of the kind studied may be minimized in flows near bank-full stage, and be higher in both sub-bank-full and overbank flows. Factors contributing to enhanced flow loss in the sub-bank-full flow studied included abstractions of flow to pools, scour holes and other low points along the channel, and overflow abstractions into channel filaments that did not rejoin the main flow. On the other hand, losses were curtailed by the shallow depth of banks wetted and by extensive mud drapes that were set down over sand bars and other porous channel materials during the flow. Thus, in contrast with the relatively regular pattern of transmission loss inferred from large floods, losses from low flows exhibit marked spatial variability and depend to a considerable extent on streamwise variations in channel geometry, in addition to the depth and porosity of channel perimeter sediments.

Particle migration and sorting in microbubble streaming flows

PubMed Central

Thameem, Raqeeb; Hilgenfeldt, Sascha

2016-01-01

Ultrasonic driving of semicylindrical microbubbles generates strong streaming flows that are robust over a wide range of driving frequencies. We show that in microchannels, these streaming flow patterns can be combined with Poiseuille flows to achieve two distinctive, highly tunable methods for size-sensitive sorting and trapping of particles much smaller than the bubble itself. This method allows higher throughput than typical passive sorting techniques, since it does not require the inclusion of device features on the order of the particle size. We propose a simple mechanism, based on channel and flow geometry, which reliably describes and predicts the sorting behavior observed in experiment. It is also shown that an asymptotic theory that incorporates the device geometry and superimposed channel flow accurately models key flow features such as peak speeds and particle trajectories, provided it is appropriately modified to account for 3D effects caused by the axial confinement of the bubble. PMID:26958103

Chemical characteristics and temporal trends in eight streams of the Catskill Mountains, New York

USGS Publications Warehouse

Murdoch, Peter S.; Stoddard, J.L.

1993-01-01

Discharge to concentration relationships for eight streams studied by the U.S. Geological Survey (USGS) as part of the U.S. Environmental Protection Agency's (U.S. EPA) Long-Term Monitoring Project (1983-89) indicate acidification of some streams by H2SO4 and HNO3 in atmospheric deposition and by organic acids in soils. Concentrations of major ions in precipitation were similar to those reported at other sites in the northeastern United States. Average concentrations of SO42- and NO3- were similar among streams, but base cation concentrations differed widely, and these differences paralleled the differences in acid neutralizing capacity (ANC). Baseflow ANC is not a reliable predictor of stream acidity at high flow; some streams with high baseflow ANC (> 150 ??eq L-1) declined to near zero ANC at high flow, and one stream with low baseflow ANC (< 50 ??eq L-1) did not approach zero ANC as flow increased. Episodic decreases in ANC and pH during peak flows were associated with increased concentrations of NO3- and dissolved organic carbon (DOC). Aluminum concentrations exceeding 300 ??g L-1 were observed during peak flows in headwater streams of the Neversink River and Rondout Creek. Seasonal Kendall Tau tests for temporal trends indicate that SO42- concentrations in streamwater generally decreased and NO3- concentrations increased during the period 1983-1989. Combined acid anion concentrations (SO42- + NO3-) were generally unchanged throughout the period of record, indicating both that the status of these streams with respect to acidic deposition is unchanged, and that NO3- is gradually replacing SO42- as the dominant acid anion in the Catskill streams.Discharge to concentration relationships for eight streams studied by the US Geological Survey (USGS) as part of the Environmental Protection Agency's (US EPA) Long-term monitoring project (19831-89) indicate acidification of some streams by H2SO4 and HNO3 in atmospheric deposition and by organic acids in soils. Concentrations of major ions in precipitations were similar to those reported at other sites in the northeastern United States. Average concentrations of SO42- and No3- were similar among streams, but base cation concentrations differed widely, and these differences parallelel the differences in acid neutralizing capacity (ANC).

ECOLOGICAL SUSTAINABILITY IN RAPIDLY URBANIZING WATERSHEDS: EVALUATING STRATEGIES DESIGNED TO MITIGATE IMPACTS ON STREAM ECOSYSTEMS

EPA Science Inventory

Urbanization has profound impacts on the hydrology and ecology of streams via alteration in water temperatures, peak and base flows, and nutrient, sediment, and contaminant inputs. Storm water management (SWM) is commonly used to reduce these impacts; however, comprehensive w...

Hydrograph separation techniques in snowmelt-dominated watersheds

NASA Astrophysics Data System (ADS)

Miller, S.; Miller, S. N.

2017-12-01

This study integrates hydrological, geochemical, and isotopic data for a better understanding of different streamflow generation pathways and residence times in a snowmelt-dominated region. A nested watershed design with ten stream gauging sites recording sub-hourly stream stage has been deployed in a snowmelt-dominated region in southeastern Wyoming, heavily impacted by the recent bark beetle epidemic. LiDAR-derived digital elevation models help elucidate effects from topography and watershed metrics. At each stream gauging site, sub-hourly stream water conductivity and temperature data are also recorded. Hydrograph separation is a useful technique for determining different sources of runoff and how volumes from each source vary over time. Following previous methods, diurnal cycles from sub-hourly recorded streamflow and specific conductance data are analyzed and used to separate hydrographs into overland flow and baseflow components, respectively. A final component, vadose-zone flow, is assumed to be the remaining water from the total hydrograph. With access to snowmelt and precipitation data from nearby instruments, runoff coefficients are calculated for the different mechanisms, providing information on watershed response. Catchments are compared to understand how different watershed characteristics translate snowmelt or precipitation events into runoff. Portable autosamplers were deployed at two of the gauging sites for high-frequency analysis of stream water isotopic composition during peak flow to compare methods of hydrograph separation. Sampling rates of one or two hours can detect the diurnal streamflow cycle common during peak snowmelt. Prior research suggests the bark beetle epidemic has had little effect on annual streamflow patterns; however, several results show an earlier shift in the day of year in which peak annual streamflow is observed. The diurnal cycle is likely to comprise a larger percentage of daily streamflow during snowmelt in post-epidemic forests, as more solar radiation is available to penetrate to the ground surface and induce snowmelt, contributing to the effect of an earlier observed peak annual streamflow.

Estimating the magnitude of peak flows at selected recurrence intervals for streams in Idaho

USGS Publications Warehouse

Berenbrock, Charles

2002-01-01

The region-of-influence method is not recommended for use in determining flood-frequency estimates for ungaged sites in Idaho because the results, overall, are less accurate and the calculations are more complex than those of regional regression equations. The regional regression equations were considered to be the primary method of estimating the magnitude and frequency of peak flows for ungaged sites in Idaho.

Obtaining Streamflow Statistics for Massachusetts Streams on the World Wide Web

USGS Publications Warehouse

Ries, Kernell G.; Steeves, Peter A.; Freeman, Aleda; Singh, Raj

2000-01-01

A World Wide Web application has been developed to make it easy to obtain streamflow statistics for user-selected locations on Massachusetts streams. The Web application, named STREAMSTATS (available at http://water.usgs.gov/osw/streamstats/massachusetts.html ), can provide peak-flow frequency, low-flow frequency, and flow-duration statistics for most streams in Massachusetts. These statistics describe the magnitude (how much), frequency (how often), and duration (how long) of flow in a stream. The U.S. Geological Survey (USGS) has published streamflow statistics, such as the 100-year peak flow, the 7-day, 10-year low flow, and flow-duration statistics, for its data-collection stations in numerous reports. Federal, State, and local agencies need these statistics to plan and manage use of water resources and to regulate activities in and around streams. Engineering and environmental consulting firms, utilities, industry, and others use the statistics to design and operate water-supply systems, hydropower facilities, industrial facilities, wastewater treatment facilities, and roads, bridges, and other structures. Until now, streamflow statistics for data-collection stations have often been difficult to obtain because they are scattered among many reports, some of which are not readily available to the public. In addition, streamflow statistics are often needed for locations where no data are available. STREAMSTATS helps solve these problems. STREAMSTATS was developed jointly by the USGS and MassGIS, the State Geographic Information Systems (GIS) agency, in cooperation with the Massachusetts Departments of Environmental Management and Environmental Protection. The application consists of three major components: (1) a user interface that displays maps and allows users to select stream locations for which they want streamflow statistics (fig. 1), (2) a data base of previously published streamflow statistics and descriptive information for 725 USGS data-collection stations, and (3) an automated procedure that determines characteristics of the land-surface area (basin) that drains to the stream and inserts those characteristics into equations that estimate the streamflow statistics. Each of these components is described and guidance for using STREAMSTATS is provided below.

Acoustic Investigation of Jet Mixing Noise in Dual Stream Nozzles

NASA Technical Reports Server (NTRS)

Khavaran, Abbas; Dahl, Milo D.

2012-01-01

In an earlier study, a prediction model for jet noise in dual stream jets was proposed that is founded on velocity scaling laws in single stream jets and similarity features of the mean velocity and turbulent kinetic energy in dual stream flows. The model forms a composite spectrum from four component single-stream jets each believed to represent noise-generation from a distinct region in the actual flow. While the methodology worked effectively at conditions considered earlier, recent examination of acoustic data at some unconventional conditions indicate that further improvements are necessary in order to expand the range of applicability of the model. The present work demonstrates how these predictions compare with experimental data gathered by NASA and industry for the purpose of examining the aerodynamic and acoustic performance of such nozzles for a wide range of core and fan stream conditions. Of particular interest are jets with inverted velocity and temperature profiles and the appearance of a second spectral peak at small aft angles to the jet under such conditions. It is shown that a four-component spectrum succeeds in modeling the second peak when the aft angle refraction effects are properly incorporated into the model. A tradeoff of noise emission takes place between two turbulent regions identified as transition and fully mixed regions as the fan stream velocity exceeds that of the core stream. The effect of nozzle discharge coefficients will also be discussed.

Estimating the Magnitude and Frequency of Peak Streamflows for Ungaged Sites on Streams in Alaska and Conterminous Basins in Canada

USGS Publications Warehouse

Curran, Janet H.; Meyer, David F.; Tasker, Gary D.

2003-01-01

Estimates of the magnitude and frequency of peak streamflow are needed across Alaska for floodplain management, cost-effective design of floodway structures such as bridges and culverts, and other water-resource management issues. Peak-streamflow magnitudes for the 2-, 5-, 10-, 25-, 50-, 100-, 200-, and 500-year recurrence-interval flows were computed for 301 streamflow-gaging and partial-record stations in Alaska and 60 stations in conterminous basins of Canada. Flows were analyzed from data through the 1999 water year using a log-Pearson Type III analysis. The State was divided into seven hydrologically distinct streamflow analysis regions for this analysis, in conjunction with a concurrent study of low and high flows. New generalized skew coefficients were developed for each region using station skew coefficients for stations with at least 25 years of systematic peak-streamflow data. Equations for estimating peak streamflows at ungaged locations were developed for Alaska and conterminous basins in Canada using a generalized least-squares regression model. A set of predictive equations for estimating the 2-, 5-, 10-, 25-, 50-, 100-, 200-, and 500-year peak streamflows was developed for each streamflow analysis region from peak-streamflow magnitudes and physical and climatic basin characteristics. These equations may be used for unregulated streams without flow diversions, dams, periodically releasing glacial impoundments, or other streamflow conditions not correlated to basin characteristics. Basin characteristics should be obtained using methods similar to those used in this report to preserve the statistical integrity of the equations.

Designing Bioretention Systems to Improve Nitrogen Removal - poster

EPA Science Inventory

Rain gardens, also referred to as bioretention systems, are designed primarily to infiltrate stormwater flow and reduce surface runoff and peak flows to receiving streams. Additionally, they are known to remove stressors from urban stormwater runoff, including oil and grease, pho...

New Jersey StreamStats: A web application for streamflow statistics and basin characteristics

USGS Publications Warehouse

Watson, Kara M.; Janowicz, Jon A.

2017-08-02

StreamStats is an interactive, map-based web application from the U.S. Geological Survey (USGS) that allows users to easily obtain streamflow statistics and watershed characteristics for both gaged and ungaged sites on streams throughout New Jersey. Users can determine flood magnitude and frequency, monthly flow-duration, monthly low-flow frequency statistics, and watershed characteristics for ungaged sites by selecting a point along a stream, or they can obtain this information for streamgages by selecting a streamgage location on the map. StreamStats provides several additional tools useful for water-resources planning and management, as well as for engineering purposes. StreamStats is available for most states and some river basins through a single web portal.Streamflow statistics for water resources professionals include the 1-percent annual chance flood flow (100-year peak flow) used to define flood plain areas and the monthly 7-day, 10-year low flow (M7D10Y) used in water supply management and studies of recreation, wildlife conservation, and wastewater dilution. Additionally, watershed or basin characteristics, including drainage area, percent area forested, and average percent of impervious areas, are commonly used in land-use planning and environmental assessments. These characteristics are easily derived through StreamStats.

Relationships between stream nitrate concentration and spatially distributed snowmelt in high-elevation catchments of the western U.S.

NASA Astrophysics Data System (ADS)

Perrot, Danielle; Molotch, Noah P.; Williams, Mark W.; Jepsen, Steven M.; Sickman, James O.

2014-11-01

This study compares stream nitrate (NO3-) concentrations to spatially distributed snowmelt in two alpine catchments, the Green Lakes Valley, Colorado (GLV4) and Tokopah Basin, California (TOK). A snow water equivalent reconstruction model and Landsat 5 and 7 snow cover data were used to estimate daily snowmelt at 30 m spatial resolution in order to derive indices of new snowmelt areas (NSAs). Estimates of NSA were then used to explain the NO3- flushing behavior for each basin over a 12 year period (1996-2007). To identify the optimal method for defining NSAs and elucidate mechanisms underlying catchment NO3- flushing, we conducted a series of regression analyses using multiple thresholds of snowmelt based on temporal and volumetric metrics. NSA indices defined by volume of snowmelt (e.g., snowmelt ≤ 30 cm) rather than snowmelt duration (e.g., snowmelt ≤ 9 days) were the best predictors of stream NO3- concentrations. The NSA indices were better correlated with stream NO3- concentration in TOK (average R2= 0.68) versus GLV4 (average R2= 0.44). Positive relationships between NSA and stream NO3- concentration were observed in TOK with peak stream NO3- concentration occurring on the rising limb of snowmelt. Positive and negative relationships between NSA and stream NO3- concentration were found in GLV4 with peak stream NO3- concentration occurring as NSA expands. Consistent with previous works, the contrasting NO3- flushing behavior suggests that streamflow in TOK was primarily influenced by overland flow and shallow subsurface flow, whereas GLV4 appeared to be more strongly influenced by deeper subsurface flow paths.

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.

The plasma wake of mesosonic conducting bodies. II - An experimental parametric study of the mid-wake ion density peak

NASA Technical Reports Server (NTRS)

Stone, N. H.

1981-01-01

An experimental investigation of the disturbed flow field created by conducting bodies in a mesosonic, collisionless plasma stream is reported. The mid-wake region is investigated, where, for bodies of the order of a Debye length in size, the focused ion streams converge to form a significant current density peak on the wake axis. A parametric description is obtained of the behavior of the amplitude, width, and position of this peak. The results also indicate that portions of the axial ion peak are created by additional mechanisms and that body geometry affects the mid-wake structure only when the sheath is sufficiently thin to conform to the shape of the body.

Dust-on-snow and the timing of peak streamflow in the upper Rio Grande

USDA-ARS?s Scientific Manuscript database

Dust radiative forcing on high elevation snowpack is well-documented in the southern Rockies. Various field studies show that dust deposits decrease snow albedo and increase absorption of solar radiation, leading to earlier snowmelt and peak stream flows. These findings have implications for the use...

Floods of December 1964 and January 1965 in the Far Western States; Part 1 Description

USGS Publications Warehouse

Waananen, A.O.; Harris, D.D.; Williams, R.C.

1971-01-01

The floods of December 1964 and January 1965 in the Far Western States were extreme; in many areas, the greatest in the history of recorded streamflow and substantially greater than those of December 1955. An unusually large area--Oregon, most of Idaho, northern California, southern Washington, and small areas in western and northern Nevada--was involved. It exceeded the area flooded in 1955. Outstanding features included recordbreaking peak discharges, high sediment concentrations, large sediment loads, and extensive flood damage. The loss of 47 lives and direct property damage of more than $430 million was attributable to the floods. Yet, storage in reservoirs and operation of flood-control facilities were effective in preventing far greater damages in many areas, particularly in the Central Valley in California and the Willamette River basin in Oregon. The floods were caused by three principal storms during the period December 19 to January 31. The December 19-23 storm was the greatest in overall intensity and areal extent. Crests occurred on many major streams December 23, 1964, 9 years to the day after the great flood of December 23, 1955. The January 2-7 storm produced extreme floods in some basins in California. The January 21-31 storm produced maximum stages in some streams in northeastern Oregon and southeastern Washington and a repetition of high flows in part of the Willamette River basin and in some basins in coastal Oregon. All the storms, and particularly the warm torrential rain December 21-23, reflected the combined effect of moist unstable airmasses, strong west-southwest winds, and mountain ranges oriented nearly at right angles to the flow of air. High air temperatures and strong winds associated with the storms caused melting of snow, and the meltwater augmented the rain that fell on frozen ground. The coastal areas of northern California and southern Oregon had measurable rain on as many as 50 days in December and January. A maximum precipitation of nearly 69 inches in the 2-month period was recorded in southern Oregon, and recorded runoff at several streamflow-measurement stations indicates that greater precipitation probably occurred at higher altitudes in these areas. Flood runoff in streams, not affected by regulation, exceeded any previously recorded throughout much of the area. Some streams that had particularly notable floods are: Deep and Plush Creeks in the Great Basin ix Oregon, where the maximum flows were nearly twice those of the record floods of 1963 ; Thomes Creek, a west-side Sacramento River tributary in the Central Valley, where the maximum flow was 160 percent of the record peak of 1955; Eel, Klamath, and Smith Rivers in north-coastal California, where the catastrophic peak flows were about 1-1/3 times the floods of 1955 and the legendary winter floods of 1861-62 and inundated, damaged, or destroyed nearly all communities along the main rivers; Grande Ronde River in the lower Snake River basin, where the peak discharge at La Grande was 1.6 times the previous maximum flow during 57 years of record; John Day River in the lower Columbia River basin, where the peak discharge at the McDonald Ferry gaging station exceeded the historic peak of 1894; many Willamette River tributaries, where maximum flows exceeded previous record flows; and the Rogue River in coastal Oregon, where the maximum flow of about 500,000 cfs below the Illinois River near Agness was 86,000 cfs greater than the previous maximum in a 74-year record. The partly regulated flow of the Willamette River far exceeded that in 1955. The suspended-sediment concentration and load of most streams greatly exceeded any that had been measured previously in the flood area. In Idaho, Washington, and Oregon, the ground thaw that preceded the period of high runoff resulted in conditions conducive to severe erosion of the uplands and subsequent deposition on flooded stream terraces. The greatest concentrations of suspended sedimen

Seasonal variations in stream chemistry in a semi-arid montane headwater stream reveal changing hydrologic flowpaths

NASA Astrophysics Data System (ADS)

Anderson, S. P.; Mills, T. J.

2016-12-01

Water delivery drives weathering and streamflow in catchments. Deciphering the loci of weathering processes and the hydrology of hillslopes requires untangling these deeply entwined systems. Highly variable water delivery compounds the problem. In the Gordon Gulch catchment of Boulder Creek CZO, ephemeral snow, convective storms, and seasonal drought produce highly variable conditions that reveal changing flowpaths contributing to streamflow. We focus on two: groundwater and shallow flow paths. Both are well expressed in the stream during relatively brief periods each year. Baseflow conditions, when streamflow is primarily derived from groundwater, occurs during seasonal drought. Commonly, this is late summer, but it can occur earlier if there is little snow or spring precipitation. We identify baseflow by its chemical signature of low or no Si-Al colloids and DOC, and high concentration of rock-weathering derived dissolved Si, Na, Ca and alkalinity. These solutes increase in concentration downstream, suggesting either a greater proportion of groundwater inputs downstream, or longer deep flowpaths downstream. Shallow flow paths connect to the stream during high flow in periods of high soil moisture from snowmelt or rain. Although annual peak discharge occurs most years from snowmelt augmented by spring rain, convective rainstorms can also drive annual peak discharge. Chemical constituents associated with these shallow connected flowpaths are DOC and Si-Al colloids, which tend to be elevated during wetter conditions in the catchment. We infer that these are mobilized from shallow soil when high soil moisture increases connectivity of shallow soil with the stream channel. These constituents do not vary in concentration downstream. A question they pose is the extent of the zone of connectivity; it seems unlikely that shallow flow paths connected to the stream channel extend far beyond the riparian corridor. Several solutes are mobilized following seasonal drought. Cl and SO4 decline in concentration on both the rising and falling limbs of the annual discharge peak. Their concentrations rise during baseflow, and spike in fall and winter. We infer that these are delivered by dry deposition, and are flushed from shallow soils by wetting events after extended dry periods.

Impact of stream restoration on flood waves

NASA Astrophysics Data System (ADS)

Sholtes, J.; Doyle, M.

2008-12-01

Restoration of channelized or incised streams has the potential to reduce downstream flooding via storing and dissipating the energy of flood waves. Restoration design elements such as restoring meanders, reducing slope, restoring floodplain connectivity, re-introducing in-channel woody debris, and re-vegetating banks and the floodplain have the capacity to attenuate flood waves via energy dissipation and channel and floodplain storage. Flood discharge hydrographs measured up and downstream of several restored reaches of varying stream order and located in both urban and rural catchments are coupled with direct measurements of stream roughness at various stages to directly measure changes to peak discharge, flood wave celerity, and dispersion. A one-dimensional unsteady flow routing model, HEC-RAS, is calibrated and used to compare attenuation characteristics between pre and post restoration conditions. Modeled sensitivity results indicate that a restoration project placed on a smaller order stream demonstrates the highest relative reduction in peak discharge of routed flood waves compared to one of equal length on a higher order stream. Reductions in bed slope, extensions in channel length, and increases in channel and floodplain roughness follow restoration placement with the watershed in relative importance. By better understanding how design, scale, and location of restored reaches within a catchment hydraulically impact flood flows, this study contributes both to restoration design and site decision making. It also quantifies the effect of reach scale stream restoration on flood wave attenuation.

Extreme Events in Urban Streams Leading to Extreme Temperatures in Birmingham, UK

NASA Astrophysics Data System (ADS)

Rangecroft, S.; Croghan, D.; Van Loon, A.; Sadler, J. P.; Hannah, D. M.

2016-12-01

Extreme flows and high water temperature events act as critical stressors on the ecological health of rivers. Urban headwater streams are considered particularly vulnerable to the effects of these extreme events. Despite this, such catchments remain poorly characterised and the effect of differences in land use is rarely quantified, especially in relation to water temperature. Thus a key research gap has emerged in understanding the patterns of water temperature during extreme events within contrasting urban, headwater catchments. We studied the headwaters of two bordering urban catchments of contrasting land use within Birmingham, UK. To characterise response to extreme events, precipitation and flow were analysed for the period of 1970-2016. To analyse the effects of extreme events on water temperature, 10 temperature loggers recording at 15 minute intervals were placed within each catchment covering a range of land use for the period May 2016 - present. During peak over threshold flood events higher average peaks were observed in the less urbanised catchment; however highest maximum flow peaks took place in the more densely urbanised catchment. Very similar average drought durations were observed between the two catchments with average flow drought durations of 27 days in the most urbanised catchment, and 29 in the less urbanised catchment. Flashier water temperature regimes were observed within the more urbanised catchment and increases of up to 5 degrees were apparent within 30 minutes during certain storms at the most upstream sites. Only in the most extreme events did the more densely urban stream appear more susceptible to both extreme high flows and extreme water temperature events, possibly resultant from overland flow emerging as the dominant flow pathway during intense precipitation events. Water temperature surges tended to be highly spatially variable indicating the importance of local land use. During smaller events, water temperature was less changeable and spatially variable, suggesting that overland flow may not the dominant flow pathway in such events. During drought events, the effect of catchment land use on water temperature was less apparent.

How snowpack heterogeneity affects diurnal streamflow timing

USGS Publications Warehouse

Lundquist, J.D.; Dettinger, M.D.

2005-01-01

Diurnal cycles of streamflow in snow-fed rivers can be used to infer the average time a water parcel spends in transit from the top of the snowpack to a stream gauge in the river channel. This travel time, which is measured as the difference between the hour of peak snowmelt in the afternoon and the hour of maximum discharge each day, ranges from a few hours to almost a full day later. Travel times increase with longer percolation times through deeper snowpacks, and prior studies of small basins have related the timing of a stream's diurnal peak to the amount of snow stored in a basin. However, in many larger basins the time of peak flow is nearly constant during the first half of the melt season, with little or no variation between years. This apparent self-organization at larger scales can be reproduced by employing heterogeneous observations of snow depths and melt rates in a model that couples porous medium flow through an evolving snowpack with free surface flow in a channel. Copyright 2005 by the American Geophysical Union.

The Shape of the Urine Stream — From Biophysics to Diagnostics

PubMed Central

Wheeler, Andrew P. S.; Morad, Samir; Buchholz, Noor; Knight, Martin M.

2012-01-01

We develop a new computational model of capillary-waves in free-jet flows, and apply this to the problem of urological diagnosis in this first ever study of the biophysics behind the characteristic shape of the urine stream as it exits the urethral meatus. The computational fluid dynamics model is used to determine the shape of a liquid jet issuing from a non-axisymmetric orifice as it deforms under the action of surface tension. The computational results are verified with experimental modelling of the urine stream. We find that the shape of the stream can be used as an indicator of both the flow rate and orifice geometry. We performed volunteer trials which showed these fundamental correlations are also observed in vivo for male healthy volunteers and patients undergoing treatment for low flow rate. For healthy volunteers, self estimation of the flow shape provided an accurate estimation of peak flow rate (). However for the patients, the relationship between shape and flow rate suggested poor meatal opening during voiding. The results show that self measurement of the shape of the urine stream can be a useful diagnostic tool for medical practitioners since it provides a non-invasive method of measuring urine flow rate and urethral dilation. PMID:23091609

Causes of acidification of four streams on Laurel Hilld in southwestern Pennsylvania

USGS Publications Warehouse

Sharpe, William E.; DeWalle, David R.; Leibfried, Robert T.; Dinicola, Richard S.; Kimmel, William G.; Sherwin, Lysle S.

1984-01-01

Atmospheric deposition, soils developed from bedrock, a natural bog, gas wells, and a ski area were all investigated as possible sources of water quality degradation for four streams on Laurel Hill in southwestern Pennsylvania where fish kills have been reported since 1960. An intensive study of the chemistry of atmospheric deposition, soil leachate, and stream water and fish populations was conducted on these basins during 1980–1981 with emphasis on dormant season periods with runoff from snowmelt and rain. Although bedrock geology was found to control the natural buffering capacity of these streams, only acid precipitation could be linked to sharp drops in pH and increases in total Al concentrations observed during stormflows in the poorly buffered streams. Three poorly buffered streams exhibited drops to pH 4.4 to 4.5 and increases in total Al concentrations up to 1.5 mg/L during observed peak flows. Mineral soil leachate from the three major soil series on the basins during this time exhibited a low pH of 4.3 and mean total Al concentrations of 3.6 mg/L, indicating stream response during storms was closely linked to chemistry of soil leachate. Poorly buffered streams did not support reproducing populations of trout (Salmonidae sp.) or other fishes. In contrast, one well-buffered stream (20 mg/L CaCO3) exhibited drops to pH 5.5 during peak flow and supported reproducing trout and sculpin (Cottus bairdi) populations. The acidification of the four streams studied was attributed to atmospheric deposition.

StreamStats in North Carolina: a water-resources Web application

USGS Publications Warehouse

Weaver, J. Curtis; Terziotti, Silvia; Kolb, Katharine R.; Wagner, Chad R.

2012-01-01

A statewide StreamStats application for North Carolina was developed in cooperation with the North Carolina Department of Transportation following completion of a pilot application for the upper French Broad River basin in western North Carolina (Wagner and others, 2009). StreamStats for North Carolina, available at http://water.usgs.gov/osw/streamstats/north_carolina.html, is a Web-based Geographic Information System (GIS) application developed by the U.S. Geological Survey (USGS) in consultation with Environmental Systems Research Institute, Inc. (Esri) to provide access to an assortment of analytical tools that are useful for water-resources planning and management (Ries and others, 2008). The StreamStats application provides an accurate and consistent process that allows users to easily obtain streamflow statistics, basin characteristics, and descriptive information for USGS data-collection sites and user-selected ungaged sites. In the North Carolina application, users can compute 47 basin characteristics and peak-flow frequency statistics (Weaver and others, 2009; Robbins and Pope, 1996) for a delineated drainage basin. Selected streamflow statistics and basin characteristics for data-collection sites have been compiled from published reports and also are immediately accessible by querying individual sites from the web interface. Examples of basin characteristics that can be computed in StreamStats include drainage area, stream slope, mean annual precipitation, and percentage of forested area (Ries and others, 2008). Examples of streamflow statistics that were previously available only through published documents include peak-flow frequency, flow-duration, and precipitation data. These data are valuable for making decisions related to bridge design, floodplain delineation, water-supply permitting, and sustainable stream quality and ecology. The StreamStats application also allows users to identify stream reaches upstream and downstream from user-selected sites and obtain information for locations along streams where activities occur that may affect streamflow conditions. This functionality can be accessed through a map-based interface with the user’s Web browser, or individual functions can be requested remotely through Web services (Ries and others, 2008).

Estimating Discharge and Nonpoint Source Nitrate Loading to Streams From Three End-Member Pathways Using High-Frequency Water Quality Data

NASA Astrophysics Data System (ADS)

Miller, Matthew P.; Tesoriero, Anthony J.; Hood, Krista; Terziotti, Silvia; Wolock, David M.

2017-12-01

The myriad hydrologic and biogeochemical processes taking place in watersheds occurring across space and time are integrated and reflected in the quantity and quality of water in streams and rivers. Collection of high-frequency water quality data with sensors in surface waters provides new opportunities to disentangle these processes and quantify sources and transport of water and solutes in the coupled groundwater-surface water system. A new approach for separating the streamflow hydrograph into three components was developed and coupled with high-frequency nitrate data to estimate time-variable nitrate loads from chemically dilute quick flow, chemically concentrated quick flow, and slowflow groundwater end-member pathways for periods of up to 2 years in a groundwater-dominated and a quick-flow-dominated stream in central Wisconsin, using only streamflow and in-stream water quality data. The dilute and concentrated quick flow end-members were distinguished using high-frequency specific conductance data. Results indicate that dilute quick flow contributed less than 5% of the nitrate load at both sites, whereas 89 ± 8% of the nitrate load at the groundwater-dominated stream was from slowflow groundwater, and 84 ± 25% of the nitrate load at the quick-flow-dominated stream was from concentrated quick flow. Concentrated quick flow nitrate concentrations varied seasonally at both sites, with peak concentrations in the winter that were 2-3 times greater than minimum concentrations during the growing season. Application of this approach provides an opportunity to assess stream vulnerability to nonpoint source nitrate loading and expected stream responses to current or changing conditions and practices in watersheds.

Carbon Isotope Composition as an Indicator of DOC Sources to a Stream During Events in a Temperate Forested Catchment

NASA Astrophysics Data System (ADS)

Doctor, D. H.; Sebestyen, S. D.; Aiken, G. R.; Shanley, J. B.; Kendall, C.; Boyer, E. W.

2006-12-01

Increased DOC flux in streams and rivers is commonly observed during high runoff regimes, however DOC concentrations alone do not provide information about multiple sources or pathways of DOC to streams. In an effort to gain this information, we measured DOC concentrations and stable carbon isotope composition (δ13C-DOC) on samples collected at high-frequency during events at Sleepers River Research Watershed in Vermont, USA. During snowmelt and storm events, peaks in stream DOC concentration (up to 10.5 mg/L) were coincident with peaks in flow. Stream water δ13C-DOC measurements ranged between -23.7‰ and - 28.9‰ and indicated changing sources of DOC during events; the highest δ13C-DOC values occurred consistently at the lowest flows, and the lowest δ13C-DOC values occurred with peaks in discharge. Water samples collected from shallow wells and stacked soil lysimeters showed the highest DOC concentrations in the most shallow (<0.5 m) lysimeter waters, and the lowest concentrations in the deeper (>1.5 m) well waters. Wells and lysimeters exhibited a range of δ13C-DOC values similar to those observed in the stream; however, samples collected from shallow horizons at nested wells and lysimeters consistently showed lower δ13C-DOC values than those from greater depths. Maple leaf litter collected from across the watershed provided an end-member of fresh organic material, with average δ13C composition of -31.3±0.7‰ (n=57), which is lower than the lowest measured DOC values in any of the stream, well, or lysimeter waters. A subset of stream waters were fractionated onto XAD4 and XAD8 resins; the hydrophobic acid fraction (XAD8) had consistently lower δ13C values than the transphilic acid fraction (XAD4), and both of these were lower than those of the bulk DOC. Samples with lower δ13C-DOC values also exhibited higher SUVA-254 values, i.e. greater aromaticity. Thus, lower δ13C-DOC values are interpreted as an indicator of relatively "fresh", more aromatic and more biologically labile material while higher δ13C-DOC values indicate relatively more degraded material. Since lower δ13C-DOC values were observed in the shallowest well and lysimeter waters and in stream water during periods of highest DOC flux, we surmise that fresh DOC is mobilized to the stream along relatively shallow flowpaths during high flows, and that a second source of more degraded DOC supplies background concentrations to the stream at lower flows.

Iron charge states observed in the solar wind

NASA Technical Reports Server (NTRS)

Ipavich, F. M.; Galvin, A. B.; Gloeckler, G.; Hovestadt, D.; Klecker, B.; Scholer, M.

1983-01-01

Solar wind measurements from the ULECA sensor of the Max-Planck-Institut/University of Maryland experiment on ISEE-3 are reported. The low energy section of approx the ULECA sensor selects particles by their energy per charge (over the range 3.6 keV/Q to 30 keV/Q) and simultaneously measures their total energy with two low-noise solid state detectors. Solar wind Fe charge state measurements from three time periods of high speed solar wind occurring during a post-shock flow and a coronal hole-associated high speed stream are presented. Analysis of the post-shock flow solar wind indicates the charge state distributions for Fe were peaked at approx +16, indicative of an unusually high coronal temperature (3,000,000 K). In contrast, the Fe charge state distribution observed in a coronal hole-associated high speed stream peaks at approx -9, indicating a much lower coronal temperature (1,400,000 K). This constitutes the first reported measurements of iron charge states in a coronal hole-associated high speed stream.

Estimating the Magnitude and Frequency of Floods in Small Urban Streams in South Carolina, 2001

USGS Publications Warehouse

Feaster, Toby D.; Guimaraes, Wladimir B.

2004-01-01

The magnitude and frequency of floods at 20 streamflowgaging stations on small, unregulated urban streams in or near South Carolina were estimated by fitting the measured wateryear peak flows to a log-Pearson Type-III distribution. The period of record (through September 30, 2001) for the measured water-year peak flows ranged from 11 to 25 years with a mean and median length of 16 years. The drainage areas of the streamflow-gaging stations ranged from 0.18 to 41 square miles. Based on the flood-frequency estimates from the 20 streamflow-gaging stations (13 in South Carolina; 4 in North Carolina; and 3 in Georgia), generalized least-squares regression was used to develop regional regression equations. These equations can be used to estimate the 2-, 5-, 10-, 25-, 50-, 100-, 200-, and 500-year recurrence-interval flows for small urban streams in the Piedmont, upper Coastal Plain, and lower Coastal Plain physiographic provinces of South Carolina. The most significant explanatory variables from this analysis were mainchannel length, percent impervious area, and basin development factor. Mean standard errors of prediction for the regression equations ranged from -25 to 33 percent for the 10-year recurrence-interval flows and from -35 to 54 percent for the 100-year recurrence-interval flows. The U.S. Geological Survey has developed a Geographic Information System application called StreamStats that makes the process of computing streamflow statistics at ungaged sites faster and more consistent than manual methods. This application was developed in the Massachusetts District and ongoing work is being done in other districts to develop a similar application using streamflow statistics relative to those respective States. Considering the future possibility of implementing StreamStats in South Carolina, an alternative set of regional regression equations was developed using only main channel length and impervious area. This was done because no digital coverages are currently available for basin development factor and, therefore, it could not be included in the StreamStats application. The average mean standard error of prediction for the alternative equations was 2 to 5 percent larger than the standard errors for the equations that contained basin development factor. For the urban streamflow-gaging stations in South Carolina, measured water-year peak flows were compared with those from an earlier urban flood-frequency investigation. The peak flows from the earlier investigation were computed using a rainfall-runoff model. At many of the sites, graphical comparisons indicated that the variance of the measured data was much less than the variance of the simulated data. Several statistical tests were applied to compare the variances and the means of the measured and simulated data for each site. The results indicated that the variances were significantly different for 11 of the 13 South Carolina streamflow-gaging stations. For one streamflow-gaging station, the test for normality, which is one of the assumptions of the data when comparing variances, indicated that neither the measured data nor the simulated data were distributed normally; therefore, the test for differences in the variances was not used for that streamflow-gaging station. Another statistical test was used to test for statistically significant differences in the means of the measured and simulated data. The results indicated that for 5 of the 13 urban streamflowgaging stations in South Carolina there was a statistically significant difference in the means of the two data sets. For comparison purposes and to test the hypothesis that there may have been climatic differences between the period in which the measured peak-flow data were measured and the period for which historic rainfall data were used to compute the simulated peak flows, 16 rural streamflow-gaging stations with long-term records were reviewed using similar techniques as those used for the measured an

Peak-flow frequency analyses and results based on data through water year 2011 for selected streamflow-gaging stations in or near Montana: Chapter C in Montana StreamStats

USGS Publications Warehouse

Sando, Steven K.; McCarthy, Peter M.; Dutton, DeAnn M.

2016-04-05

Chapter C of this Scientific Investigations Report documents results from a study by the U.S. Geological Survey, in cooperation with the Montana Department of Transportation and the Montana Department of Natural Resources, to provide an update of statewide peak-flow frequency analyses and results for Montana. The purpose of this report chapter is to present peak-flow frequency analyses and results for 725 streamflow-gaging stations in or near Montana based on data through water year 2011. The 725 streamflow-gaging stations included in this study represent nearly all streamflowgaging stations in Montana (plus some from adjacent states or Canadian Provinces) that have at least 10 years of peak-flow records through water year 2011. For 29 of the 725 streamflow-gaging stations, peak-flow frequency analyses and results are reported for both unregulated and regulated conditions. Thus, peak-flow frequency analyses and results are reported for a total of 754 analyses. Estimates of peak-flow magnitudes for 66.7-, 50-, 42.9-, 20-, 10-, 4-, 2-, 1-, 0.5-, and 0.2-percent annual exceedance probabilities are reported. These annual exceedance probabilities correspond to 1.5-, 2-, 2.33-, 5-, 10-, 25-, 50-, 100-, 200-, and 500-year recurrence intervals.

Flow Resistance Interactions on Hillslopes With Heterogeneous Attributes: Effects on Runoff Hydrograph Characteristics

NASA Astrophysics Data System (ADS)

Papanicolaou, Athanasios N.; Abban, Benjamin K. B.; Dermisis, Dimitrios C.; Giannopoulos, Christos P.; Flanagan, Dennis C.; Frankenberger, James R.; Wacha, Kenneth M.

2018-01-01

An improved modeling framework for capturing the effects of space and time-variant resistance to overland flow is developed for intensively managed landscapes. The framework builds on the WEPP model but it removes the limitations of the "equivalent" plane and time-invariant roughness assumption. The enhanced model therefore accounts for spatiotemporal changes in flow resistance along a hillslope due to changes in roughness, in profile curvature, and downslope variability. The model is used to quantify the degree of influence—from individual soil grains to aggregates, "isolated roughness elements," and vegetation—on overland flow characteristics under different storm magnitudes, downslope gradients, and profile curvatures. It was found that the net effects of land use change from vegetation to a bare surface resulted in hydrograph peaks that were up to 133% larger. Changes in hillslope profile curvature instead resulted in peak runoff rate changes that were only up to 16%. The stream power concept is utilized to develop a taxonomy that relates the influence of grains, isolated roughness elements, and vegetation, on overland flow under different storm magnitudes and hillslope gradients. Critical storm magnitudes and hillslope gradients were found beyond which the effects of these landscape attributes on the peak stream power were negligible. The results also highlight weaknesses of the space/time-invariant flow resistance assumption and demonstrate that assumptions on landscape terrain characteristics exert a strong control both on the shape and magnitude of hydrographs, with deviations reaching 65% in the peak runoff when space/time-variant resistance effects are ignored in some cases.

Traveltime and longitudinal dispersion in Illinois streams

USGS Publications Warehouse

Graf, Julia B.

1986-01-01

Twenty-seven measurements of traveltime and longitudinal dispersion in 10 Illinois streams made from 1975 to 1982 provide data needed for estimating traveltime of peak concentration of a conservative solute, traveltime of the leading edge of a solute cloud, peak concentration resulting from injection of a given quantity of solute, and passage time of solute past a given point on a stream. These four variables can be estimated graphically for each stream from distance of travel and either discharge at the downstream end of the reach or flow-duration frequency. From equations developed from field measurements, the traveltime and dispersion characteristics also can be estimated for other unregulated streams in Illinois that have drainage areas less than about 1,500 square miles. For unmeasured streams, traveltime of peak concentration and of the leading edge of the cloud are related to discharge at the downstream end of the reach and to distance of travel. For both measured and unmeasured streams, peak concentration and passage time are best estimated from the relation of each to traveltime. In measured streams, dispersion efficiency is greater than that predicted by Fickian diffusion theory. The rate of decrease in peak concentration with traveltime is about equal to the rate of increase in passage time. Average velocity in a stream reach, given by the velocity of the center of solute mass in that reach, can be estimated from an equation developed from measured values. The equation relates average reach velocity to discharge at the downstream end of the reach. Average reach velocities computed for 9 of the 10 streams from available equations that are based on hydraulic-geometry relations are high relative to measured values. The estimating equation developed from measured velocities provides estimates of average reach velocity that are closer to measured velocities than are those computed using equations developed from hydraulic-geometry relations.

Modeling the effects of LID practices on streams health at watershed scale

NASA Astrophysics Data System (ADS)

Shannak, S.; Jaber, F. H.

2013-12-01

Increasing impervious covers due to urbanization will lead to an increase in runoff volumes, and eventually increase flooding. Stream channels adjust by widening and eroding stream bank which would impact downstream property negatively (Chin and Gregory, 2001). Also, urban runoff drains in sediment bank areas in what's known as riparian zones and constricts stream channels (Walsh, 2009). Both physical and chemical factors associated with urbanization such as high peak flows and low water quality further stress aquatic life and contribute to overall biological condition of urban streams (Maxted et al., 1995). While LID practices have been mentioned and studied in literature for stormwater management, they have not been studied in respect to reducing potential impact on stream health. To evaluate the performance and the effectiveness of LID practices at a watershed scale, sustainable detention pond, bioretention, and permeable pavement will be modeled at watershed scale. These measures affect the storm peak flows and base flow patterns over long periods, and there is a need to characterize their effect on stream bank and bed erosion, and aquatic life. These measures will create a linkage between urban watershed development and stream conditions specifically biological health. The first phase of this study is to design and construct LID practices at the Texas A&M AgriLife Research and Extension Center-Dallas, TX to collect field data about the performance of these practices on a smaller scale. The second phase consists of simulating the performance of LID practices on a watershed scale. This simulation presents a long term model (23 years) using SWAT to evaluate the potential impacts of these practices on; potential stream bank and bed erosion, and potential impact on aquatic life in the Blunn Watershed located in Austin, TX. Sub-daily time step model simulations will be developed to simulate the effectiveness of the three LID practices with respect to reducing potential erosion from stream beds and banks by studying annual average excess shear and reducing potential impact on aquatic life by studying rapid changes and variation in flow regimes in urban streams. This study will contribute to develop a methodology that evaluates the impact of hydrological changes that occur due to urban development, on aquatic life, stream bank and bed erosion. This is an ongoing research project and results will be shared and discussed at the conference.

Contrasts in Flushing Patterns Among Solutes

NASA Astrophysics Data System (ADS)

Shanley, J. B.; Sebestyen, S. D.; Boyer, E. W.; Ross, D. S.

2005-12-01

High-frequency sampling since 1991 at the 41-ha forested W-9 catchment at Sleepers River, Vermont provides a wealth of data to evaluate catchment flushing responses. Snowmelt and rain-on-snow account for about half the annual flow at Sleepers River during a 6-week period in early spring. Summer and fall storms produce frequent high-flows of short duration. Flushing of weathering products (Ca, Mg, Na, K, SO4 ANC, Si) is generally supply-limited, and is masked by rapid dilution with meteoric and soil water during events. In contrast, flushing dominates the stream dynamics of atmospheric and pedogenic solutes (NO3, DOC, Hg), causing concentration increases with increasing flow. During snowmelt, NO3 peaks well before the peak in discharge, whereas DOC tracks discharge closely and peaks concurrently. These patterns suggest that NO3 is supply-limited and DOC is transport-limited; W-9 is not N saturated and the available NO3 supply is readily leached from the soil, whereas stream DOC progressively increases as rising water tables and expanding saturated areas connect with new source areas. In summer storms, DOC and NO3 both peak simultaneously with discharge. Unlike DOC, however, NO3 concentrations are attenuated with subsequent storms that follow within a few days, consistent with a depletion of the NO3 pool available for flushing as observed during snowmelt. Sleepers River contrasts with the Snake River in Colorado, where NO3 and DOC reverse roles; DOC peaks early in snowmelt and may be supply-limited due to the paucity of organic matter. An ample supply of NO3 is available due to N saturation and N fixation, but NO3 may be transport-limited due to primary N sources in talus deposits far from the stream. Hg is an atmospheric solute that accumulates in soils because of its affinity for organic matter, and is flushed by high flows, mostly in association with suspended sediment. The concept of flushing provides a useful context for understanding the variable responses of solutes to the expansion of catchment saturation during high flow events.

Methodology for Estimation of Flood Magnitude and Frequency for New Jersey Streams

USGS Publications Warehouse

Watson, Kara M.; Schopp, Robert D.

2009-01-01

Methodologies were developed for estimating flood magnitudes at the 2-, 5-, 10-, 25-, 50-, 100-, and 500-year recurrence intervals for unregulated or slightly regulated streams in New Jersey. Regression equations that incorporate basin characteristics were developed to estimate flood magnitude and frequency for streams throughout the State by use of a generalized least squares regression analysis. Relations between flood-frequency estimates based on streamflow-gaging-station discharge and basin characteristics were determined by multiple regression analysis, and weighted by effective years of record. The State was divided into five hydrologically similar regions to refine the regression equations. The regression analysis indicated that flood discharge, as determined by the streamflow-gaging-station annual peak flows, is related to the drainage area, main channel slope, percentage of lake and wetland areas in the basin, population density, and the flood-frequency region, at the 95-percent confidence level. The standard errors of estimate for the various recurrence-interval floods ranged from 48.1 to 62.7 percent. Annual-maximum peak flows observed at streamflow-gaging stations through water year 2007 and basin characteristics determined using geographic information system techniques for 254 streamflow-gaging stations were used for the regression analysis. Drainage areas of the streamflow-gaging stations range from 0.18 to 779 mi2. Peak-flow data and basin characteristics for 191 streamflow-gaging stations located in New Jersey were used, along with peak-flow data for stations located in adjoining States, including 25 stations in Pennsylvania, 17 stations in New York, 16 stations in Delaware, and 5 stations in Maryland. Streamflow records for selected stations outside of New Jersey were included in the present study because hydrologic, physiographic, and geologic boundaries commonly extend beyond political boundaries. The StreamStats web application was developed cooperatively by the U.S. Geological Survey and the Environmental Systems Research Institute, Inc., and was designed for national implementation. This web application has been recently implemented for use in New Jersey. This program used in conjunction with a geographic information system provides the computation of values for selected basin characteristics, estimates of flood magnitudes and frequencies, and statistics for stream locations in New Jersey chosen by the user, whether the site is gaged or ungaged.

Estimating Peak-Flow Frequency Statistics for Selected Gaged and Ungaged Sites in Naturally Flowing Streams and Rivers in Idaho

DOT National Transportation Integrated Search

2017-03-01

Reliable estimates of the magnitude and frequency of floods are needed by Federal, regional, State, and local infrastructure designers and water-resource managers for the design of highway, road, and other bridge crossings of rivers, delineation of f...

Estimating the gas and dye quantities for modified tracer technique measurements of stream reaeration coefficients

USGS Publications Warehouse

Rathbun, R.E.

1979-01-01

Measuring the reaeration coefficient of a stream with a modified tracer technique has been accomplished by injecting either ethylene or ethylene and propane together and a rhodamine-WT dye solution into the stream. The movement of the tracers through the stream reach after injection is described by a one-dimensional diffusion equation. The peak concentrations of the tracers at the downstream end of the reach depend on the concentrations of the tracers in the stream at the injection site, the longitudinal dispersion coefficient, the mean water velocity, the length of the reach, and the duration of the injection period. The downstream gas concentrations also depend on the gas desorption coefficients of the reach. The concentrations of the tracer gases in the stream at the injection site depend on the flow rates of the gases through the injection diffusers, the efficiency of the gas absorption process, and the stream discharge. The concentration of dye in the stream at the injection site depends on the flow rate of the dye solution, the concentration of the dye solution, and the stream discharge. Equations for estimating the gas flow rates, the quantities of the gases, the dye concentration, and the quantity of dye together with procedures for determining the variables in these equations are presented. (Woodard-USGS)

Does harvest in west slope Douglas-fir increase peak flow in small forest streams?

Treesearch

Jack. Rothatcher

1973-01-01

Logging in Douglas-fir has only minor effect on major peak streamflows that occur when soils are thoroughly wet. Exceptions are the early fall storms following the dry summers characteristic of the west coast climate. At this time, peak streamflow from unlogged areas may be less than from the harvested area because the soil in the unlogged area is drier and has greater...

Surface Water Data at Los Alamos National Laboratory: 2002 Water Year

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

D.A. Shaull; D. Ortiz; M.R. Alexander

2003-03-03

The principal investigators collected and computed surface water discharge data from 34 stream-gaging stations that cover most of Los Alamos National Laboratory and one at Bandelier National Monument. Also included are discharge data from three springs--two that flow into Canon de Valle and one that flows into Water Canyon--and peak flow data from 16 stations.

Surface Water Data at Los Alamos National Laboratory 2006 Water Year

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

R.P. Romero, D. Ortiz, G. Kuyumjian

2007-08-01

The principal investigators collected and computed surface water discharge data from 44 stream-gaging stations that cover most of Los Alamos National Laboratory and one at Bandelier National Monument. Also included are discharge data from three springs--two that flow into Canon de Valle and one that flows into Water Canyon--and peak flow data for 44 stations.

Classical and generalized Horton laws for peak flows in rainfall-runoff events.

PubMed

Gupta, Vijay K; Ayalew, Tibebu B; Mantilla, Ricardo; Krajewski, Witold F

2015-07-01

The discovery of the Horton laws for hydrologic variables has greatly lagged behind geomorphology, which began with Robert Horton in 1945. We define the classical and the generalized Horton laws for peak flows in rainfall-runoff events, which link self-similarity in network geomorphology with river basin hydrology. Both the Horton laws are tested in the Iowa River basin in eastern Iowa that drains an area of approximately 32 400 km(2) before it joins the Mississippi River. The US Geological Survey continuously monitors the basin through 34 stream gauging stations. We select 51 rainfall-runoff events for carrying out the tests. Our findings support the existence of the classical and the generalized Horton laws for peak flows, which may be considered as a new hydrologic discovery. Three different methods are illustrated for estimating the Horton peak-flow ratio due to small sample size issues in peak flow data. We illustrate an application of the Horton laws for diagnosing parameterizations in a physical rainfall-runoff model. The ideas and developments presented here offer exciting new directions for hydrologic research and education.

Space Vehicle Valve System

NASA Technical Reports Server (NTRS)

Kelley, Anthony R. (Inventor); Lindner, Jeffrey L. (Inventor)

2014-01-01

The present invention is a space vehicle valve system which controls the internal pressure of a space vehicle and the flow rate of purged gases at a given internal pressure and aperture site. A plurality of quasi-unique variable dimension peaked valve structures cover the purge apertures on a space vehicle. Interchangeable sheet guards configured to cover valve apertures on the peaked valve structure contain a pressure-activated surface on the inner surface. Sheet guards move outwardly from the peaked valve structure when in structural contact with a purge gas stream flowing through the apertures on the space vehicle. Changing the properties of the sheet guards changes the response of the sheet guards at a given internal pressure, providing control of the flow rate at a given aperture site.

Development of the Hydroecological Integrity Assessment Process for Determining Environmental Flows for New Jersey Streams

USGS Publications Warehouse

Kennen, Jonathan G.; Henriksen, James A.; Nieswand, Steven P.

2007-01-01

The natural flow regime paradigm and parallel stream ecological concepts and theories have established the benefits of maintaining or restoring the full range of natural hydrologic variation for physiochemical processes, biodiversity, and the evolutionary potential of aquatic and riparian communities. A synthesis of recent advances in hydroecological research coupled with stream classification has resulted in a new process to determine environmental flows and assess hydrologic alteration. This process has national and international applicability. It allows classification of streams into hydrologic stream classes and identification of a set of non-redundant and ecologically relevant hydrologic indices for 10 critical sub-components of flow. Three computer programs have been developed for implementing the Hydroecological Integrity Assessment Process (HIP): (1) the Hydrologic Indices Tool (HIT), which calculates 171 ecologically relevant hydrologic indices on the basis of daily-flow and peak-flow stream-gage data; (2) the New Jersey Hydrologic Assessment Tool (NJHAT), which can be used to establish a hydrologic baseline period, provide options for setting baseline environmental-flow standards, and compare past and proposed streamflow alterations; and (3) the New Jersey Stream Classification Tool (NJSCT), designed for placing unclassified streams into pre-defined stream classes. Biological and multivariate response models including principal-component, cluster, and discriminant-function analyses aided in the development of software and implementation of the HIP for New Jersey. A pilot effort is currently underway by the New Jersey Department of Environmental Protection in which the HIP is being used to evaluate the effects of past and proposed surface-water use, ground-water extraction, and land-use changes on stream ecosystems while determining the most effective way to integrate the process into ongoing regulatory programs. Ultimately, this scientifically defensible process will help to quantify the effects of anthropogenic changes and development on hydrologic variability and help planners and resource managers balance current and future water requirements with ecological needs.

Temperature Regulation in Critical Salmon Habitat of the Middle Fork of the John Day River, Oregon.

NASA Astrophysics Data System (ADS)

Buskirk, B. A.; Selker, J. S.

2016-12-01

Flow and temperature within the Middle Fork of the John Day River, an arid Eastern Oregon river, is dominated primarily by contributions from groundwater fed tributaries. The hydrology of arid streams is an important metric for understanding the critical environment in which salmon spawn and salmonids reside. The regulation of temperature within these streams is considered the primary metric for survival rates of these fish. Since 2007 Oregon State University has conducted stream monitoring efforts on the Middle Fork of the John Day River at the Oxbow and Forrest Conservation Areas. These sites were chosen through collaborative effort with the Confederated Tribes of the Warm Springs Reservation of Oregon, who have been restoring remnant mining canals back to their natural sinuous river pattern. The John Day River is also one of the few undammed reaches in which salmon runs occur. Efforts have focused on fiber optic distributed temperature sensing (DTS), groundwater gradient, stream discharge, bed permeability, GPS location and stream bathymetry across the conservation sites. During the peak of summer, stream temperature exhibits a strong diurnal cycle ranging from 9° C to 23° C depending on the daily maximum observed within the reach. Salmon have been found to be sensitive to stream temperatures above 15° C and are unable to survive temperatures above 24° C (Bell et al, 1991). The synthesis of temperature and stream flow data we collected show that very little groundwater is contributing to flow and temperature in the main channel of our study site while tributaries provide a constant, typically 0.5 to 2° C cooler, input of water to the main river channel and significant source of flow (0.01 - 0.1 m3/s). Due to the minimal rain fall in this arid environment, snow melt infiltration is likely the primary annual source of recharge into the head waters of the tributaries while also providing temperature regulation through input of near 0° C water. This cold water input from tributaries in addition to bank overhanging sedge grass provide cool safe zones for the young and mature fish during peak summer temperatures.

A geographic information system tool to solve regression equations and estimate flow-frequency characteristics of Vermont Streams

USGS Publications Warehouse

Olson, Scott A.; Tasker, Gary D.; Johnston, Craig M.

2003-01-01

Estimates of the magnitude and frequency of streamflow are needed to safely and economically design bridges, culverts, and other structures in or near streams. These estimates also are used for managing floodplains, identifying flood-hazard areas, and establishing flood-insurance rates, but may be required at ungaged sites where no observed flood data are available for streamflow-frequency analysis. This report describes equations for estimating flow-frequency characteristics at ungaged, unregulated streams in Vermont. In the past, regression equations developed to estimate streamflow statistics required users to spend hours manually measuring basin characteristics for the stream site of interest. This report also describes the accompanying customized geographic information system (GIS) tool that automates the measurement of basin characteristics and calculation of corresponding flow statistics. The tool includes software that computes the accuracy of the results and adjustments for expected probability and for streamflow data of a nearby stream-gaging station that is either upstream or downstream and within 50 percent of the drainage area of the site where the flow-frequency characteristics are being estimated. The custom GIS can be linked to the National Flood Frequency program, adding the ability to plot peak-flow-frequency curves and synthetic hydrographs and to compute adjustments for urbanization.

Factors controlling mercury transport in an upland forested catchment

USGS Publications Warehouse

Scherbatskoy, T.; Shanley, J.B.; Keeler, G.J.

1998-01-01

Total mercury (Hg) deposition and input/output relationships were investigated in an 11-ha deciduous forested catchment in northern Vermont as part of ongoing evaluations of rig cycling and transport in the Lake Champlain basin. Atmospheric Hg deposition (precipitation + modeled vapor phase downward flux) was 425 mg ha-1 during the one-year period March 1994 through February 1995 and 463 mg ha-1 from March 1995 through February 1996. In the same periods, stream export of total Hg was 32 mg ha-1 and 22 mg ha-1, respectively. Thus, there was a net retention of Hg by the catchment of 92% the first year and 95% the second year. In the first year, 16.9 mg ha-1 or about half of the annual stream export, occurred on the single day of peak spring snowmelt in April. In contrast, the maximum daily export in the second year, when peak stream flow was somewhat lower, was 3.5 mg ha-1 during a January thaw. The fate of file Hg retained by this forested catchment is not known. Dissolved (< 0.22 ??m) Hg concentrations in stream water ranged from 0.5-2.6 ng L-1, even when total (unfiltered) concentrations were greater than 10 ng L-1 during high flow events. Total Hg concentrations in stream water were correlated with the total organic fraction of suspended sediment, suggesting the importance of organic material in Hg transport within the catchment. High flow events and transport with organic material may be especially important mechanisms for the movement of Hg through forested ecosystems.

Downstream effects of stream flow diversion on channel characteristics and riparian vegetation in the Colorado Rocky Mountains, USA

Treesearch

Simeon T. Caskey; Tyanna S. Blaschak; Ellen Wohl; Elizabeth Schnackenberg; David M. Merritt; Kathleen A. Dwire

2015-01-01

Flow diversions are widespread and numerous throughout the semi-arid mountains of the western United States. Diversions vary greatly in their structure and ability to divert water, but can alter the magnitude and duration of base and peak flows, depending upon their size and management. Channel geometry and riparian plant communities have adapted to unique hydrologic...

Methods and equations for estimating peak streamflow per square mile in Virginia’s urban basins

USGS Publications Warehouse

Austin, Samuel H.

2014-01-01

Models are presented that describe Virginia urban area annual peak streamflow per square mile based on basin percent urban area and basin drainage area. Equations are provided to estimate Virginia urban peak flow per square mile of basin drainage area in each of the following annual exceedance probability categories: 0.995, 0.99, 0.95, 0.9, 0.8, 0.67, 0.5, 0.43, 0.2, 0.1, 0.04, 0.02, 0.01, 0.005, and 0.002 (recurrence intervals of 1.005, 1.01, 1.05, 1.11, 1.25, 1.49, 2.0, 2.3, 5, 10, 25, 50, 100, 200, and 500 years, respectively). Equations apply to Virginia drainage basins ranging in size from no less than 1.2 mi2 to no more than 2,400 mi2 containing at least 10 percent urban area, and not more than 96 percent urban area. A total of 115 Virginia drainage basins were analyzed. Actual-by-predicted plots and leverage plots for response variables and explanatory variables in each peak-flow annual exceedance probability category indicate robust model fits and significant explanatory power. Equations for 8 of 15 urban peak-flow response surface models yield R-square values greater than 0.8. Relations identified in statistical models, describing significant increases in urban peak stream discharges as basin urban area increases, affirm empirical relations reported in past studies of change in stream discharge, lag times, and physical streamflow processes, most notably those detailed for urban areas in northern Virginia.

Overview of surface-water resources at the U.S. Coast Guard Support Center Kodiak, Alaska, 1987-89

USGS Publications Warehouse

Solin, G.L.

1996-01-01

Hydrologic data at a U.S. Coast Guard Support Center on Kodiak Island, Alaska, were collected from 1987 though 1989 to determine hydrologic conditions and if contamination of soils, ground water, or surface water has occurred. This report summarizes the surface-water-discharge data collected during the study and estimates peak, average, and low-flow values for Buskin River near its mouth. Water-discharge measurements were made at least once at 48 sites on streams in or near the Center. Discharges were measured in the Buskin River near its mouth five times during 1987-89 and ranged from 27 to 367 cubic feet per second. Tributaries of Buskin River below Buskin Lake that had discharges greater than 1 cubic foot per second include Bear Creek, Alder Creek, Magazine Creek, Devils Creek and an outlet from Lake Louise. Streams having flows generally greater than 0.1 cubic foot per second but less than 1 cubic foot per second include an unnamed tributary to Buskin River, an unnamed tributary to Lake Catherine and a drainage channel at Kodiak airport. Most other streams flowing into Buskin River, and all streams on Nyman Peninsula, usually had little or no flow except during periods of rainfall or snowmelt. During a low-flow period in February 1989, discharge measurements in Buskin River and its tributaries indicate that three reaches of Buskin River below Buskin Lake lost water to the ground-water system, whereas two reaches gained water; the net gain in streamflow attributed to ground-water inflow at a location near the mouth was estimated to be 2.2 cubic feet per second. The 100-year peak flow for Buskin River near its mouth was estimated to be 4,460 cubic feet per second. Average discharge was estimated to be 125 cubic feet per second and the 7-day 10-year low flow was estimated to be 5.8 cubic feet per second.

Impact of Fluidic Chevrons on Supersonic Jet Noise

NASA Technical Reports Server (NTRS)

Henderson, Brenda; Norum, Thomas

2007-01-01

The impact of fluidic chevrons on broadband shock noise and mixing noise for single stream and coannular jets was investigated. Air was injected into the core flow of a bypass ratio 5 nozzle system using a core fluidic chevron nozzle. For the single stream experiments, the fan stream was operated at the wind tunnel conditions and the core stream was operated at supersonic speeds. For the dual stream experiments, the fan stream was operated at supersonic speeds and the core stream was varied between subsonic and supersonic conditions. For the single stream jet at nozzle pressure ratio (NPR) below 2.0, increasing the injection pressure of the fluidic chevron increased high frequency noise at observation angles upstream of the nozzle exit and decreased mixing noise near the peak jet noise angle. When the NPR increased to a point where broadband shock noise dominated the acoustic spectra at upstream observation angles, the fluidic chevrons significantly decreased this noise. For dual stream jets, the fluidic chevrons reduced broadband shock noise levels when the fan NPR was below 2.3, but had little or no impact on shock noise with further increases in fan pressure. For all fan stream conditions investigated, the fluidic chevron became more effective at reducing mixing noise near the peak jet noise angle as the core pressure increased.

Streamflow, water-temperature, and specific-conductance data for selected streams draining into Lake Fryxell, lower Taylor Valley, Victoria Land, Antarctica, 1990-92

USGS Publications Warehouse

Von Guerard, Paul; McKnight, Diane M.; Harnish, R.A.; Gartner, J.W.; Andrews, E.D.

1995-01-01

During the 1990-91 and 1991-92 field seasons in Antarctica, streamflow, water-temperature, and specific-conductance data were collected on the major streams draining into Lake Fryxell. Lake Fryxell is a permanently ice-covered, closed-basin lake with 13 tributary streams. Continuous streamflow data were collected at eight sites, and periodic streamflow measurements were made at three sites. Continuous water-temperature and specific- conductance data were collected at seven sites, and periodic water-temperature and specific-conductance data were collected at all sites. Streamflow for all streams measured ranged from 0 to 0.651 cubic meter per second. Water temperatures for all streams measured ranged from 0 to 14.3 degrees Celsius. Specific conductance for all streams measured ranged from 11 to 491 microsiemens per centimeter at 25 degrees Celsius. It is probable that stream- flow in the Lake Fryxell Basin during 1990-92 was greater than average. Examination of the 22-year streamflow record in the Onyx River in the Wright Valley revealed that in 1990 streamflow began earlier than for any previous year recorded and that the peak streamflow of record was exceeded. Similar high-flow conditions occurred during the 1991-92 field season. Thus, the data collected on streams draining into Lake Fryxell during 1990-92 are representative of greater than average stream- flow conditions.

Geology, Streamflow, and Water Chemistry of the Talufofo Stream Basin, Saipan, Northern Mariana Islands

USGS Publications Warehouse

Izuka, Scot K.; Ewart, Charles J.

1995-01-01

A study of the geology, streamflow, and water chemistry of Talufofo Stream Basin, Saipan, Commonwealth of the Northern Mariana Islands, was undertaken to determine the flow characteristics of Talufofo Stream and the relation to the geology of the drainage basin. The Commonwealth government is exploring the feasibility of using water from Talufofo Stream to supplement Saipan's stressed municipal water supply. Streamflow records from gaging stations on the principal forks of Talufofo Stream indicate that peak streamflows and long-term average flow are higher at the South Fork gaging station than at the Middle Fork gaging station because the drainage area of the South Fork gaging station is larger, but persistent base flow from ground-water discharge during dry weather is greater in the Middle Fork gaging station. The sum of the average flows at the Middle Fork and South Fork gaging stations, plus an estimate of the average flow at a point in the lower reaches of the North Fork, is about 2.96 cubic feet per second or 1.91 million gallons per day. Although this average represents the theoretical maximum long-term draft rate possible from the Talufofo Stream Basin if an adequate reservoir can be built, the actual amount of surface water available will be less because of evaporation, leaks, induced infiltration, and reservoir-design constraints. Base-flow characteristics, such as stream seepage and spring discharge, are related to geology of the basin. Base flow in the Talufofo Stream Basin originates as discharge from springs near the base of limestones located in the headwaters of Talufofo Stream, flows over low-permeability volcanic rocks in the middle reaches, and seeps back into the high-permeability limestones in the lower reaches. Water sampled from Talufofo Stream during base flow had high dissolved-calcium concentrations (between 35 and 98 milligrams per liter), characteristic of water from a limestone aquifer. Concentrations of potassium, sodium, and chloride ions in water samples from Talufofo Stream are characteristic of water draining a heavily vegetated basin near the ocean. The streamflow and water-chemistry data indicate that discharge from springs is in hydraulic connection with the limestone aquifer near the headwaters of the basin. The base flow therefore is subject to stresses placed on the nearby limestone ground-water system. Pumping from wells in the limestones at the headwaters of Talufofo Stream Basin may decrease spring flow in Talufofo Stream.

Forests and water

Treesearch

Graeme Lockaby; Chelsea Nagy; James M. Vose; Chelcy R. Ford; Ge Sun; Steve McNulty; Pete Caldwell; Erika Cohen; Jennifer Moore Myers

2013-01-01

Key FindingsForest conversion to agriculture or urban use consistently causes increased discharge, peak flow, and velocity of streams. Subregional differences in hydrologic responses to urbanization are substantial.Sediment, water chemistry indices, pathogens, and other substances often become more concentrated after forest...

Effects of Wildfire on the Hydrology of Capulin and Rito de los Frijoles canyons, Bandelier National Monument, New Mexico

USGS Publications Warehouse

Veenhuis, Jack E.

2002-01-01

In June of 1977, the La Mesa wildfire burned 15,270 acres in and around Frijoles Canyon in Bandelier National Monument and the adjacent Santa Fe National Forest, New Mexico. The Dome wildfire in April of 1996 in Bandelier National Monument burned 16,516 acres in Capulin Canyon and the surrounding Dome Wilderness area. Both watersheds are characterized by abundant and extensive archeological sites that could be affected by increased runoff and accelerated rates of erosion, which typically occur after a wildfire. The U.S. Geological Survey in cooperation with the National Park Service monitored the wildfires' effects on streamflow in both canyons. The magnitude of large stormflows increased dramatically after these wildfires; peak flows at the most downstream streamflow-gaging station in Frijoles and Capulin Canyons increased to about 160 times the maximum recorded flood prior to the fire. Maximum peak flow was 3,030 cubic feet per second at the gaging station in Frijoles Canyon (drainage area equals 18.1 square miles) and 3,630 cubic feet per second at the most downstream crest-stage gage in Capulin Canyon (drainage area equals 14.1 square miles). The pre-fire maximum peak flow recorded in these two canyons was 19 and an estimated 25 cubic feet per second, respectively. As vegetation reestablished itself during the second year, the post-fire annual maximum peak flow decreased to about 10 to 15 times the pre-fire annual maximum peak flow. During the third year, maximum annual peak flows decreased to about three to five times the pre-fire maximum peak flow. In the 22 years since the La Mesa wildfire, flood magnitudes have not completely returned to pre-fire size. Post-fire flood magnitudes in Frijoles and Capulin Canyons do not exceed the maximum floods per drainage area for physiographic regions 5 and 6 in New Mexico. For a burned watershed, however, the peak flows that occur after a wildfire are several orders of magnitude larger than normal forested watershed peak flows. The frequency of larger stormflows also increased in response to the effects of the wildfires in both canyons. In Frijoles Canyon, the number of peak stormflows greater than the pre-fire maximum flow of 19 cubic feet per second was 15 in 1977, 9 in 1978, and 5 in 1979, which is about the magnitude of the maximum pre-fire peak flow in both canyons. Again the hydrologic effects of a wildfire seem to be more pronounced for the 3 years following the date of the fire. Likewise, larger peakflows occurred more frequently in Capulin Canyon for the first 3 years after the 1996 wildfire. Median suspended-sediment concentrations in samples collected in Frijoles Canyon in 1977 were 1,330 milligrams per liter; median concentrations were 16 milligrams per liter after the watershed stabilized in 1993-95. The annual load calculated from regression equations for load compared to flow for the first year after the wildfire was 220 times the annual load for the post-recovery period. To convey the increased frequency and magnitude of average flows in Capulin Canyon after the 1996 Dome wildfire, the stream channel in Capulin Canyon increased in flow capacity by widening and downcutting. As Capulin Canyon peak flows have decreased in both magnitude and frequency with vegetative recovery, the stream channel also has slowly begun to readjust. The channel at the most downstream crest-stage gage, which has the shallowest initial valley slope, is showing the first signs of aggradation.

Floods of March 1978, in the Maumee River basin, northeastern Indiana

USGS Publications Warehouse

Hoggatt, Richard Earl

1981-01-01

Floods in the Maumee River basin in northeastern Indiana in March 1978 resulted in heavy damage in Fort Wayne and surrounding areas. Flood damage in Fort Wayne was estimated by the Mayor to be 11 million dollars. Approximately 15 percent of the city was inundated, and 2,400 of its 190,000 residents were forced to leave their homes. The estimate of damage in Adams and Allen Counties by Civil Defense officials was 44 million dollars. The Maumee River at New Haven exceeded the peak stage of record, 21.4 feet, by 2.2 feet. The peak discharge at this stream-gaging station, 22,400 cubic feet per second, was about equal to that of a 75-year flood. Recurrence intervals of peak flows on streams tributary to the Maumee River ranged from 5 to 50 years. Records of peak and daily discharges and some precipitation data are given in this report. 

Transport of bedload sediment and channel morphology of a southeast Alaska stream.

Treesearch

Margaret A. Estep; Robert L. Beschta

1985-01-01

During 1980-81, transport of bedload sediment and channel morphology were determined at Trap Bay Creek, a third-order stream that drains a 13.5-square kilometer watershed on Chichagof island in southeast Alaska. Bedload sediment was sampled for 10 storms: peak flows ranged from 0.6 to 19.0 cubic meters per second, and transport rates ranged from 4 to 4400 kilograms per...

PIV Study on Flow around Leading-Edge Slat of 30P30N Airfoil

NASA Astrophysics Data System (ADS)

Ando, Ryosuke; Onishi, Yusaku; Sakakibara, Jun

2017-11-01

We measured flow velocity distribution around leading-edge slat using PIV. Simultaneously, noise measurement using microphone was also performed. A leading-edge slat and main wing model having a chord length of 160 mm was placed in the tunnel with free stream velocity of about 26m/s and chord Reynolds number of 2.8 x 105. Angle of attack was changed from 4 degrees to 10 degrees at two degree intervals. In this experiment, we investigated the relationship between the unsteady flow condition and the noise. At 4 degrees in the angle of attack, vortices shedding from the slat cusp were moved to the downstream. At 6 degrees or more, flow velocity distributions show that vortices were reattached on the slat lower surface and the flow in the slat cove recirculated. In FFT analysis of noise measurement, at 6 degrees in the angle of attack, there were some peaks on low frequency area and dominant peak on high frequency area was found. At 8 degrees or more, there were also some peaks on low frequency area. But dominant peak on high frequency area disappeared.

Speciation and equilibrium relations of soluble aluminum in a headwater stream at base flow and during rain events

USGS Publications Warehouse

Burns, Douglas A.

1989-01-01

In a small watershed in the Shenandoah National Park, Virginia, the short-term dynamics of soluble aluminum in stream water sampled during rain events differed significantly from stream water sampled during base flow conditions. Three fractions of dissolved aluminum were measured. The inorganic monomeric fraction made up approximately two thirds of the total reactive aluminum at base flow, followed by the acid-soluble and organic monomeric fractions, respectively. Equilibrium modeling showed that hydroxide complexes were the most abundant form of inorganic monomeric aluminum followed by fluoride, free aluminum ion, and sulfate. The activity of inorganic monomeric aluminum at base flow appears to be in equilibrium with an Al(OH)3 phase with solubility intermediate between microcrystalline gibbsite and natural gibbsite. During two rain events, the concentration of all three aluminum fractions increased significantly. Available chemical evidence indicates that acidic soil water was the primary source of dissolved aluminum. As flow increased, the Al(OH)3 saturation index in the stream water increased significantly. The primary cause of the transient increase in the Al(OH)3 saturation index appears to have been the neutralization of excess H+ added by soil water through reaction with stream water HCO3− at a more rapid rate than excess inorganic monomeric aluminum could be removed from solution by hydroxide mineral precipitation. A soil water/stream water mixing model was developed based on measured changes of stream water alkalinity, silica concentration, and charge imbalance during the rain events. Model results indicate that a small amount of soil water (3–11%) was present in the stream at peak stage.

Stormflow response to roadbuilding and partial cutting in small streams of northern California

Treesearch

Robert R. Ziemer

1981-01-01

To assess the influence of road building and logging on storm flow response, a pair of watersheds were studied at Caspar Creek near Fort Bragg in northern California from 1963 to 1975. Selection cutting and tractor yarding of 85-year-old second-growth redwood and Douglas-fir forest did not significantly affect large peak streamflows. The first streamflow peaks in the...

Geochemistry of stream-sediment samples from the Santa Renia Fields and Beaver Peak quadrangles, northern Carlin Trend, Nevada

USGS Publications Warehouse

Theodore, Ted G.; Kotlyar, Boris B.; Berger, Vladimir I.; Moring, Barry C.; Singer, Donald A.; Edstrom, Sven A.

1999-01-01

A broad west-to-east increase of many metal concentrations has been found in stream sediments during a reconnaissance investigation conducted in conjunction with geologic studies in the Santa Renia Fields and Beaver Peak 7–1/2 minute quadrangles near the northern end of the Carlin trend of gold deposits in the Tuscarora Mountains. This regional increase in metal concentrations coincides with a dramatic change in landform wherein high concentrations of metals in stream sediments appear to correlate directly with areas of high elevations and steep slopes in the Beaver Peak quadrangle. Robust erosion combined with high flow rates in streams from these higher elevations are envisaged to have contributed significantly to increased metal concentrations in the stream sediments by an enhanced presence of minerals with high specific gravities and a correspondingly diminished presence of minerals with low specific gravities. Minerals with low specific gravities probably have been preferentially flushed down stream because of high transporting capacities for sediment by streams in the Beaver Peak quadrangle. In addition, the Carlin trend, a generally northwest-alignment of gold deposits in the Santa Renia Fields quadrangle, is well outlined by arsenic concentrations that include a maximum of approximately 54 parts per million. Further, a weakly developed distal-to-proximal metal zonation towards these gold deposits appears to be defined respectively in plots showing distributions of thallium, arsenic, antimony, and zinc. A broad area of high metal concentrations—including sharply elevated abundances of Ag, As, Au, Cd, Co, Cu, Mn, Ni, P, Sb, Sc, Te, V, and especially Zn—near the southeast corner of the Beaver Peak quadrangle primarily could be the result of stratiform mineralized rocks in the Ordovician Vinini Formation or Devonian Slaven Chert, or the result of a subsequent Mesozoic or Tertiary epigenetic overprint.

Regression Equations for Estimating Flood Flows at Selected Recurrence Intervals for Ungaged Streams in Pennsylvania

USGS Publications Warehouse

Roland, Mark A.; Stuckey, Marla H.

2008-01-01

Regression equations were developed for estimating flood flows at selected recurrence intervals for ungaged streams in Pennsylvania with drainage areas less than 2,000 square miles. These equations were developed utilizing peak-flow data from 322 streamflow-gaging stations within Pennsylvania and surrounding states. All stations used in the development of the equations had 10 or more years of record and included active and discontinued continuous-record as well as crest-stage partial-record stations. The state was divided into four regions, and regional regression equations were developed to estimate the 2-, 5-, 10-, 50-, 100-, and 500-year recurrence-interval flood flows. The equations were developed by means of a regression analysis that utilized basin characteristics and flow data associated with the stations. Significant explanatory variables at the 95-percent confidence level for one or more regression equations included the following basin characteristics: drainage area; mean basin elevation; and the percentages of carbonate bedrock, urban area, and storage within a basin. The regression equations can be used to predict the magnitude of flood flows for specified recurrence intervals for most streams in the state; however, they are not valid for streams with drainage areas generally greater than 2,000 square miles or with substantial regulation, diversion, or mining activity within the basin. Estimates of flood-flow magnitude and frequency for streamflow-gaging stations substantially affected by upstream regulation are also presented.

Tracing Nitrate Contributions to Streams During Varying Flow Regimes at the Sleepers River Research Watershed, Vermont, USA

NASA Astrophysics Data System (ADS)

Sebestyen, S. D.; Shanley, J. B.; Boyer, E. W.; Ohte, N.; Doctor, D. H.; Kendall, C.

2003-12-01

Quantifying sources and transformations of nitrate in headwater catchments is fundamental to understanding the movement of nitrogen to streams. At the Sleepers River Research Watershed in northeastern Vermont (USA), we are using multiple chemical tracer and mixing model approaches to quantify sources and transport of nitrate to streams under varying flow regimes. We sampled streams, lysimeters, and wells at nested locations from the headwaters to the outlet of the 41 ha W-9 watershed under the entire range of flow regimes observed throughout 2002-2003, including baseflow and multiple events (stormflow and snowmelt). Our results suggest that nitrogen sources, and consequently stream nitrate concentrations, are rapidly regenerated during several weeks of baseflow and nitrogen is flushed from the watershed by stormflow events that follow baseflow periods. Both basic chemistry data (anions, cations, & dissolved organic carbon) and isotopic data (nitrate, dissolved organic carbon, and dissolved inorganic carbon) indicate that nitrogen source contributions vary depending upon the extent of saturation in the watershed, the initiation of shallow subsurface water inputs, and other hydrological processes. Stream nitrate concentrations typically peak with discharge and are higher on the falling than the rising limb of the hydrograph. Our data also indicate the importance of terrestrial and aquatic biogeochemical processes, in addition to hydrological connectivity in controlling how nitrate moves from the terrestrial landscape to streams. Our detailed sampling data from multiple flow regimes are helping to identify and quantify the "hot spots" and "hot moments" of biogeochemical and hydrological processes that control nitrogen fluxes in streams.

Scaling relationships between bed load volumes, transport distances, and stream power in steep mountain channels

NASA Astrophysics Data System (ADS)

Schneider, Johannes M.; Turowski, Jens M.; Rickenmann, Dieter; Hegglin, Ramon; Arrigo, Sabrina; Mao, Luca; Kirchner, James W.

2014-03-01

Bed load transport during storm events is both an agent of geomorphic change and a significant natural hazard in mountain regions. Thus, predicting bed load transport is a central challenge in fluvial geomorphology and natural hazard risk assessment. Bed load transport during storm events depends on the width and depth of bed scour, as well as the transport distances of individual sediment grains. We traced individual gravels in two steep mountain streams, the Erlenbach (Switzerland) and Rio Cordon (Italy), using magnetic and radio frequency identification tags, and measured their bed load transport rates using calibrated geophone bed load sensors in the Erlenbach and a bed load trap in the Rio Cordon. Tracer transport distances and bed load volumes exhibited approximate power law scaling with both the peak stream power and the cumulative stream energy of individual hydrologic events. Bed load volumes scaled much more steeply with peak stream power and cumulative stream energy than tracer transport distances did, and bed load volumes scaled as roughly the third power of transport distances. These observations imply that large bed load transport events become large primarily by scouring the bed deeper and wider, and only secondarily by transporting the mobilized sediment farther. Using the sediment continuity equation, we can estimate the mean effective thickness of the actively transported layer, averaged over the entire channel width and the duration of individual flow events. This active layer thickness also followed approximate power law scaling with peak stream power and cumulative stream energy and ranged up to 0.57 m in the Erlenbach, broadly consistent with independent measurements.

Characterization of Three-Stream Jet Flow Fields

NASA Technical Reports Server (NTRS)

Henderson, Brenda S.; Wernet, Mark P.

2016-01-01

Flow-field measurements were conducted on single-, dual- and three-stream jets using two-component and stereo Particle Image Velocimetry (PIV). The flow-field measurements complimented previous acoustic measurements. The exhaust system consisted of externally-plugged, externally-mixed, convergent nozzles. The study used bypass-to-core area ratios equal to 1.0 and 2.5 and tertiary-to-core area ratios equal to 0.6 and 1.0. Axisymmetric and offset tertiary nozzles were investigated for heated and unheated high-subsonic conditions. Centerline velocity decay rates for the single-, dual- and three-stream axisymmetric jets compared well when axial distance was normalized by an equivalent diameter based on the nozzle system total exit area. The tertiary stream had a greater impact on the mean axial velocity for the small bypass-to-core area ratio nozzles than for large bypass-to-core area ratio nozzles. Normalized turbulence intensities were similar for the single-, dual-, and three-stream unheated jets due to the small difference (10 percent) in the core and bypass velocities for the dual-stream jets and the low tertiary velocity (50 percent of the core stream) for the three-stream jets. For heated jet conditions where the bypass velocity was 65 percent of the core velocity, additional regions of high turbulence intensity occurred near the plug tip which were not present for the unheated jets. Offsetting the tertiary stream moved the peak turbulence intensity levels upstream relative to those for all axisymmetric jets investigated.

Characterization of Three-Stream Jet Flow Fields

NASA Technical Reports Server (NTRS)

Henderson, Brenda S.; Wernet, Mark P.

2016-01-01

Flow-field measurements were conducted on single-, dual- and three-stream jets using two-component and stereo Particle Image Velocimetry (PIV). The flow-field measurements complimented previous acoustic measurements. The exhaust system consisted of externally-plugged, externally-mixed, convergent nozzles. The study used bypass-to-core area ratios equal to 1.0 and 2.5 and tertiary-to-core area ratios equal to 0.6 and 1.0. Axisymmetric and offset tertiary nozzles were investigated for heated and unheated high-subsonic conditions. Centerline velocity decay rates for the single-, dual- and three-stream axisymmetric jets compared well when axial distance was normalized by an equivalent diameter based on the nozzle system total exit area. The tertiary stream had a greater impact on the mean axial velocity for the small bypass-to-core area ratio nozzles than for large bypass-to-core area ratio nozzles. Normalized turbulence intensities were similar for the single-, dual-, and three-stream unheated jets due to the small difference (10%) in the core and bypass velocities for the dual-stream jets and the low tertiary velocity (50% of the core stream) for the three-stream jets. For heated jet conditions where the bypass velocity was 65% of the core velocity, additional regions of high turbulence intensity occurred near the plug tip which were not present for the unheated jets. Offsetting the tertiary stream moved the peak turbulence intensity levels upstream relative to those for all axisymmetric jets investigated.

Source water controls on the character and origin of dissolved organic matter in streams of the Yukon River basin, Alaska

USGS Publications Warehouse

O'Donnell, Jonathan A.; Aiken, George R.; Kane, Evan S.; Jones, Jeremy B.

2010-01-01

Climate warming and permafrost degradation at high latitudes will likely impact watershed hydrology, and consequently, alter the concentration and character of dissolved organic carbon (DOC) in northern rivers. We examined seasonal variation of DOC chemistry in 16 streams of the Yukon River basin, Alaska. Our primary objective was to evaluate the relationship between source water (shallow versus deep groundwater flow paths) and DOC chemical composition. Using base cation chemistry and principal component analysis, we observed high contributions of deep groundwater to glacial and clearwater streams, whereas blackwater streams received larger contributions from shallow groundwater sources. DOC concentration and specific ultraviolet absorbance peaked during spring snowmelt in all streams, and were consistently higher in blackwater streams than in glacial and clearwater streams. The hydrophobic acid fraction of DOC dominated across all streams and seasons, comprising between 35% and 56% of total DOC. The hydrophilic acid fraction of DOC was more prominent in glacial (23% ± 3%) and clearwater streams (19% ± 1%) than in blackwater streams (16% ± 1%), and was enriched during winter base flow (29% ± 1%) relative to snowmelt and summer base flow. We observed that an increase in the contribution of deep groundwater to streamflow resulted in decreased DOC concentration, aromaticity, and DOC-to-dissolved organic nitrogen ratio, and an increase in the proportion of hydrophilic acids relative to hydrophobic acids. Our findings suggest that future permafrost degradation and higher contributions of groundwater to streamflow may result in a higher fraction of labile DOM in streams of the Yukon basin.

Montana StreamStats

USGS Publications Warehouse

2016-04-05

About this volumeMontana StreamStats is a Web-based geographic information system (http://water.usgs.gov/osw/streamstats/) application that provides users with access to basin and streamflow characteristics for gaged and ungaged streams in Montana. Montana StreamStats was developed by the U.S. Geological Survey (USGS) in cooperation with the Montana Departments of Transportation, Environmental Quality, and Natural Resources and Conservation. The USGS Scientific Investigations Report consists of seven independent but complementary chapters dealing with various aspects of this effort.Chapter A describes the Montana StreamStats application, the basin and streamflow datasets, and provides a brief overview of the streamflow characteristics and regression equations used in the study. Chapters B through E document the datasets, methods, and results of analyses to determine streamflow characteristics, such as peak-flow frequencies, low-flow frequencies, and monthly and annual characteristics, for USGS streamflow-gaging stations in and near Montana. The StreamStats analytical toolsets that allow users to delineate drainage basins and solve regression equations to estimate streamflow characteristics at ungaged sites in Montana are described in Chapters F and G.

Downstream reduction of rural channel size with contrasting urban effects in small coastal streams of southeastern Australia

NASA Astrophysics Data System (ADS)

Nanson, G. C.; Young, R. W.

1981-07-01

Although most streams show a downstream increase in channel size corresponding to a downstream increase in flood discharges, those flowing off the Illawarra escarpment of New South Wales show a marked reduction of channel size, accompanied by a down-stream increase in flood frequency in their lower reaches. Within the confined and steeply sloping valleys of the escarpment foothills, bed and bank sediments are relatively coarse and uncohesive, and channels increase in size, corresponding to increasing discharge downstream. However, once these streams emerge into more open rural valleys at lower slopes and are accompanied by extensive floodplains formed of fine cohesive sediment, there is a dramatic reduction in channel size. This decrease in channel size apparently results from a sudden decline in channel slope and associated stream power, the cohesive nature of downstream alluvium, its retention on the channel banks by a dense cover of pasture grasses, and the availability of an extensive floodplain to carry displaced floodwater. Under these conditions floodwaters very frequently spill out over the floodplain and the downstream channel-flow becomes a relatively unimportant component of the total peak discharge. This emphasizes the importance of these floodplains as a part of the total channel system. In situations where urban development has increased peak runoff and reduced the available area of effective floodplain, stream channels formed in this fine alluvium rapidly entrench and increase in cross-sectional area by 2-3 times. Minor man-induced channel alteration and maintenance appears to trigger this enlargement.

Methods for estimating magnitude and frequency of peak flows for small watersheds in Utah.

DOT National Transportation Integrated Search

2010-06-01

Determining discharge in a stream is important to the design of culverts, bridges, and other structures pertaining to : transportation systems. Currently in Utah regression equations exist to estimate recurrence flood year discharges for : rural wate...

Acoustic investigation of wall jet over a backward-facing step using a microphone phased array

NASA Astrophysics Data System (ADS)

Perschke, Raimund F.; Ramachandran, Rakesh C.; Raman, Ganesh

2015-02-01

The acoustic properties of a wall jet over a hard-walled backward-facing step of aspect ratios 6, 3, 2, and 1.5 are studied using a 24-channel microphone phased array at Mach numbers up to M=0.6. The Reynolds number based on inflow velocity and step height assumes values from Reh = 3.0 ×104 to 7.2 ×105. Flow without and with side walls is considered. The experimental setup is open in the wall-normal direction and the expansion ratio is effectively 1. In case of flow through a duct, symmetry of the flow in the spanwise direction is lost downstream of separation at all but the largest aspect ratio as revealed by oil paint flow visualization. Hydrodynamic scattering of turbulence from the trailing edge of the step contributes significantly to the radiated sound. Reflection of acoustic waves from the bottom plate results in a modulation of power spectral densities. Acoustic source localization has been conducted using a 24-channel microphone phased array. Convective mean-flow effects on the apparent source origin have been assessed by placing a loudspeaker underneath a perforated flat plate and evaluating the displacement of the beamforming peak with inflow Mach number. Two source mechanisms are found near the step. One is due to interaction of the turbulent wall jet with the convex edge of the step. Free-stream turbulence sound is found to be peaked downstream of the step. Presence of the side walls increases free-stream sound. Results of the flow visualization are correlated with acoustic source maps. Trailing-edge sound and free-stream turbulence sound can be discriminated using source localization.

Lower Velocity Sites Improve the Tidal-Stream Energy Resource

NASA Astrophysics Data System (ADS)

Robins, P. E.; Lewis, M. J.; Neill, S. P.; Hashemi, M. R.; Stephenson, G.

2015-12-01

It is essential that developers have detailed knowledge of the tidal-stream energy resource. ROMS hydrodynamic models (~1 km resolution) of key areas in northwest Europe, were used to examine the spatial and temporal distribution of the tidal-stream resource. Currently, sites with peak spring tide velocities (M2 and S2 constituents) in excess of 2.5 m/s and water depths between 25 and 50 m are preferred. When assuming this so-called "1st generation" criteria, a limited resource with limited scope for long-term sustainability of the industry was calculated for the Irish Sea; a key area for UK development. Selecting sites that also included 20% lower velocities (>2 m/s) and deeper water locations (>25m) resulted in a seven-fold increase in the available resource (for the Irish Sea). Although new engineering challenges will be encountered (e.g. more wave exposed locations) by developing these 2nd generation tidal-stream energy sites (>2m/s and >25m), some oceanographic challenges would be improved. For example, the flood-ebb tidal flow is not typically rectilinear at 1st generation UK sites (a mean error from rectilinear of ~20° in this assumption), which is reduced to near-rectilinear flow (˜3° error) when including 2nd generation sites. Analysis of our northwest European model revealed more phase diversity is offered by developing lower tidal energy sites, allowing firm and constant electricity generation. Moreover, at 1st generation sites, we calculate significant, and unaccounted, variability in annual practical power generation. For example, mean peak spring tidal velocities can under-estimate the annual practical resource by up to 25%, for regions experiencing similar mean peak spring tidal velocities, due to the ratio of M2 and S2, together with the influence of other tidal constituents, such as K1 and O1. Therefore, based on prevalence, firm power and engineering challengers, we find a strong case for developing lower flow technologies.

Debris flow-induced topographic changes: effects of recurrent debris flow initiation.

PubMed

Chen, Chien-Yuan; Wang, Qun

2017-08-12

Chushui Creek in Shengmu Village, Nantou County, Taiwan, was analyzed for recurrent debris flow using numerical modeling and geographic information system (GIS) spatial analysis. The two-dimensional water flood and mudflow simulation program FLO-2D were used to simulate debris flow induced by rainfall during typhoon Herb in 1996 and Mindulle in 2004. Changes in topographic characteristics after the debris flows were simulated for the initiation of hydrological characteristics, magnitude, and affected area. Changes in topographic characteristics included those in elevation, slope, aspect, stream power index (SPI), topographic wetness index (TWI), and hypsometric curve integral (HI), all of which were analyzed using GIS spatial analysis. The results show that the SPI and peak discharge in the basin increased after a recurrence of debris flow. The TWI was higher in 2003 than in 2004 and indicated higher potential of landslide initiation when the slope of the basin was steeper. The HI revealed that the basin was in its mature stage and was shifting toward the old stage. Numerical simulation demonstrated that the parameters' mean depth, maximum depth, affected area, mean flow rate, maximum flow rate, and peak flow discharge were increased after recurrent debris flow, and peak discharge occurred quickly.

Identifying sources of stream water sulfate after a summer drought in the Sleepers River watershed (Vermont, USA) using hydrological, chemical, and isotopic techniques

USGS Publications Warehouse

Mayer, B.; Shanley, J.B.; Bailey, S.W.; Mitchell, M.J.

2010-01-01

In many forested headwater catchments, peak SO42 - concentrations in stream water occur in the late summer or fall following drought potentially resulting in episodic stream acidification. The sources of highly elevated stream water SO42 - concentrations were investigated in a first order stream at the Sleepers River watershed (Vermont, USA) after the particularly dry summer of 2001 using a combination of hydrological, chemical and isotopic approaches. Throughout the summer of 2001 SO42 - concentrations in stream water doubled from ???130 to 270 ??eq/L while flows decreased. Simultaneously increasing Na+ and Ca2+ concentrations and ??34S values increasing from +7??? towards those of bedrock S (???+10.5???) indicated that chemical weathering involving hydrolysis of silicates and oxidation of sulfide minerals in schists and phyllites was the cause for the initial increase in SO42 - concentrations. During re-wetting of the watershed in late September and early October of 2001, increasing stream flows were accompanied by decreasing Na+ and Ca2+ concentrations, but SO42 - concentrations continued to increase up to 568 ??eq/L, indicating that a major source of SO42 - in addition to bedrock weathering contributed to peak SO42 - concentrations. The further increase in SO42 - concentrations coincided with an abrupt decrease of ??34S values in stream water SO42 - from maximum values near +10??? to minimum values near -3???. Soil investigations revealed that some C-horizons in the Spodsols of the watershed contained secondary sulfide minerals with ??34S values near -22???. The shift to negative ??34S values of stream water SO42 - indicates that secondary sulfides in C-horizons were oxidized to SO42 - during the particularly dry summer of 2001. The newly formed SO42 - was transported to the streams during re-wetting of the watershed contributing ???60% of the SO42 - during peak concentrations in the stream water. Thereafter, the contribution of SO42 - from oxidation of secondary sulfides in C-horizons decreased rapidly and pedogenic SO42 - reemerged as a dominant SO42 - source in concert with decreasing SO42 - concentrations in spring of 2002. The study provides evidence that a quantitative assessment of the sources of stream water SO42 - in forested watersheds is possible by combining hydrological, chemical and isotopic techniques, provided that the isotopic compositions of all potential SO42 - sources are distinctly different. ?? 2010 Elsevier Ltd.

Frequency dependence and frequency control of microbubble streaming flows

NASA Astrophysics Data System (ADS)

Wang, Cheng; Rallabandi, Bhargav; Hilgenfeldt, Sascha

2013-02-01

Steady streaming from oscillating microbubbles is a powerful actuating mechanism in microfluidics, enjoying increased use due to its simplicity of manufacture, ease of integration, low heat generation, and unprecedented control over the flow field and particle transport. As the streaming flow patterns are caused by oscillations of microbubbles in contact with walls of the set-up, an understanding of the bubble dynamics is crucial. Here we experimentally characterize the oscillation modes and the frequency response spectrum of such cylindrical bubbles, driven by a pressure variation resulting from ultrasound in the range of 1 kHz raisebox {-.9ex{stackrel{textstyle <}{˜ }} }f raisebox {-.9ex{stackrel{textstyle <}{˜ }} } 100 kHz. We find that (i) the appearance of 2D streaming flow patterns is governed by the relative amplitudes of bubble azimuthal surface modes (normalized by the volume response), (ii) distinct, robust resonance patterns occur independent of details of the set-up, and (iii) the position and width of the resonance peaks can be understood using an asymptotic theory approach. This theory describes, for the first time, the shape oscillations of a pinned cylindrical bubble at a wall and gives insight into necessary mode couplings that shape the response spectrum. Having thus correlated relative mode strengths and observed flow patterns, we demonstrate that the performance of a bubble micromixer can be optimized by making use of such flow variations when modulating the driving frequency.

Magnitude and frequency of floods in Washington

USGS Publications Warehouse

Cummans, J.E.; Collings, Michael R.; Nasser, Edmund George

1975-01-01

Relations are provided to estimate the magnitude and frequency of floods on Washington streams. Annual-peak-flow data from stream gaging stations on unregulated streams having 1 years or more of record were used to determine a log-Pearson Type III frequency curve for each station. Flood magnitudes having recurrence intervals of 2, 5, i0, 25, 50, and 10years were then related to physical and climatic indices of the drainage basins by multiple-regression analysis using the Biomedical Computer Program BMDO2R. These regression relations are useful for estimating flood magnitudes of the specified recurrence intervals at ungaged or short-record sites. Separate sets of regression equations were defined for western and eastern parts of the State, and the State was further subdivided into 12 regions in which the annual floods exhibit similar flood characteristics. Peak flows are related most significantly in western Washington to drainage-area size and mean annual precipitation. In eastern Washington-they are related most significantly to drainage-area size, mean annual precipitation, and percentage of forest cover. Standard errors of estimate of the estimating relations range from 25 to 129 percent, and the smallest errors are generally associated with the more humid regions.

Modeling pesticide loadings from the San Joaquin watershed into the Sacramento-San Joaquin Delta using SWAT

NASA Astrophysics Data System (ADS)

Chen, H.; Zhang, M.

2016-12-01

The Sacramento-San Joaquin Delta is an ecologically rich, hydrologically complex area that serves as the hub of California's water supply. However, pesticides have been routinely detected in the Delta waterways, with concentrations exceeding the benchmark for the protection of aquatic life. Pesticide loadings into the Delta are partially attributed to the San Joaquin watershed, a highly productive agricultural watershed located upstream. Therefore, this study aims to simulate pesticide loadings to the Delta by applying the Soil and Water Assessment Tool (SWAT) model to the San Joaquin watershed, under the support of the USDA-ARS Delta Area-Wide Pest Management Program. Pesticide use patterns in the San Joaquin watershed were characterized by combining the California Pesticide Use Reporting (PUR) database and GIS analysis. Sensitivity/uncertainty analyses and multi-site calibration were performed in the simulation of stream flow, sediment, and pesticide loads along the San Joaquin River. Model performance was evaluated using a combination of graphic and quantitative measures. Preliminary results indicated that stream flow was satisfactorily simulated along the San Joaquin River and the major eastern tributaries, whereas stream flow was less accurately simulated in the western tributaries, which are ephemeral small streams that peak during winter storm events and are mainly fed by irrigation return flow during the growing season. The most sensitive parameters to stream flow were CN2, SOL_AWC, HRU_SLP, SLSUBBSN, SLSOIL, GWQMN and GW_REVAP. Regionalization of parameters is important as the sensitivity of parameters vary significantly spatially. In terms of evaluation metric, NSE tended to overrate model performance when compared to PBIAS. Anticipated results will include (1) pesticide use pattern analysis, (2) calibration and validation of stream flow, sediment, and pesticide loads, and (3) characterization of spatial patterns and temporal trends of pesticide yield.

Stream Width Dynamics in a Small Headwater Catchment

NASA Astrophysics Data System (ADS)

Barefoot, E. A.; Pavelsky, T.; Allen, G. H.; Zimmer, M. A.; McGlynn, B. L.

2016-12-01

Changing streamflow conditions cause small, ephemeral and intermittent stream networks to expand and contract, while simultaneously driving widening and narrowing of streams. The resulting dynamic surface area of ephemeral streams impacts critical hydrological and biogeochemical processes, including air-water gas exchange, solute transport, and sediment transport. Despite the importance of these dynamics, to our knowledge there exists no complete study of how stream widths vary throughout an entire catchment in response to changing streamflow conditions. Here we present the first characterization of how variable hydrologic conditions impact the distribution of stream widths in a 48 ha headwater catchment in the Stony Creek Research Watershed, NC, USA. We surveyed stream widths longitudinally every 5 m on 12 occasions over a range of stream discharge from 7 L/s to 128 L/s at the catchment outlet. We hypothesize that the shape and location of the stream width distribution are driven by the action of two interrelated mechanisms, network extension and at-a-station widening, both of which increase with discharge. We observe that during very low flow conditions, network extension more significantly influences distribution location, and during high flow conditions stream widening is the dominant driver. During moderate flows, we observe an approximately 1 cm rightward shift in the distribution peak with every additional 10 L/s of increased discharge, which we attribute to a greater impact of at-a-station widening on distribution location. Aside from this small shift, the qualitative location and shape of the stream width distribution are largely invariant with changing streamflow. We suggest that the basic characteristics of stream width distributions constitute an equilibrium between the two described mechanisms across variable hydrologic conditions.

Effects of urbanization on streamflow in the Atlanta area (Georgia, USA): A comparative hydrological approach

USGS Publications Warehouse

Rose, S.; Peters, N.E.

2001-01-01

For the period from 1958 to 1996, streamflow characteristics of a highly urbanized watershed were compared with less-urbanized and non-urbanized watersheds within a 20 000 km2 region in the vicinity of Atlanta, Georgia: In the Piedmont and Blue Ridge physiographic provinces of the southeastern USA. Water levels in several wells completed in surficial and crystalline-rock aquifers were also evaluated. Data were analysed for seven US Geological Survey (USGS) stream gauges, 17 National Weather Service rain gauges, and five USGS monitoring wells. Annual runoff coefficients (RCs; runoff as a fractional percentage of precipitation) for the urban stream (Peachtree Creek) were not significantly greater than for the less-urbanized watersheds. The RCs for some streams were similar to others and the similar streams were grouped according to location. The RCs decreased from the higher elevation and higher relief watersheds to the lower elevation and lower relief watersheds: Values were 0.54 for the two Blue Ridge streams. 0.37 for the four middle Piedmont streams (near Atlanta), and 0.28 for a southern Piedmont stream. For the 25 largest stormflows, the peak flows for Peachtree Creek were 30% to 100% greater then peak flows for the other stream. The storm recession period for the urban stream was 1-2 days less than that for the other streams and the recession was characterized by a 2-day storm recession constant that was, on average, 40 to 100% greater, i.e. streamflow decreased more rapidly than for the other streams. Baseflow recession constants ranged from 35 to 40% lower for Peachtree Creek than for the other streams; this is attributed to lower evapotranspiration losses, which result in a smaller change in groundwater storage than in the less-urbanized watersheds. Low flow of Peachtree Creek ranged from 25 to 35% less than the other streams, possibly the result of decreased infiltration caused by the more efficient routing of stormwater and the paving of groundwater rechange areas. The timing of daily or monthly groundwater-level fluctuations was similar annually in each well, reflecting the seasonal recharge. Although water-level monitoring only began in the 1980s for the two urban wells, water levels displayed a notable decline compared with non-urban wells since then; this is attributed to decreased groundwater rechange in the urban watersheds due to increased imperviousness and related rapid storm runoff. Copyright ?? 2001 John Wiley & Sons, Ltd.

Detection of dual effects of degradation of perennial snow and ice covers on the hydrologic regime of a Himalayan river basin by stream water availability modeling

NASA Astrophysics Data System (ADS)

Mukhopadhyay, Biswajit

2012-01-01

SummaryIn river basins where melt water from snow and ice constitutes a dominant component of stream discharge during summer, degradation or reduction of perennial snow and ice covered areas ( SCA P) has a profound effect on stream water availability in those basins. Degradation of SCA P that includes glaciers is a globally widespread phenomenon observed in the recently past decades; its cause has been attributed to global warming and its consequence is expected to dramatically alter the flow regimes of the rivers draining the terrains. The predicted change in flow regime is an initial increase in summer flows in the early decades of 21st century followed by sharp decline of the same during the later parts of the century. Estimation of SCA P within the Upper Indus Basin (UIB), straddling the western ranges of the Greater Himalayas, Karakoram Mountains, and the eastern mountain ranges of the Hindu Kush, shows that from 1992 to 2010 there has been about 2.15% reduction in SCA P. A spatially distributed basin-scale stream water availability model is presented to calculate monthly river discharges at critical hydrologic junctions within UIB. Model calculations for the years 1992, 2000, and 2008, show that due to the degradation of the SCA P within the basin, there has been significant decrease in summer discharges at various hydrologic junctions. The percentage decline in flows varies from 10% to 22%, depending on the locations of the junctions within the basin. The space-dependence of these variations reflects differential degradation of SCA P in various parts of the basin. Furthermore, the time of peak discharge at all of the hydrological junctions has shifted from middle/late summer to late spring/early summer as another outcome of SCA P reduction. Such temporal shifting of nival regimes to early part of warmer season has also been predicted by global warming models. However, the case study presented here for a major Himalayan river basin demonstrates that such shifting of peak discharge in the time domain can also take place simply due to retreat of the equilibrium line. Thus, the effects of a warming climate have possibly been already set within UIB. Instead of experiencing an increased pulse of summer flows for the next few decades, summer flows within this basin are expected to decline. Changes in the timing of peak flows can have adverse effects on multipurpose water resources management without appropriate adaptation and mitigation measures. Monthly average stream flow data with 35 year period of record from a key gauging station support the findings of the model results. Similarly, digital maps of SCA P at different time periods within a key catchment of UIB, containing one of the major glaciers, show retreat of glacial lobes and significant decrease in total SCA P taking place during the past decades.

Effects of Urbanization on the Flow Regimes of Semi-Arid Southern California Streams

NASA Astrophysics Data System (ADS)

Hawley, R. J.; Bledsoe, B. P.; Stein, E. D.

2010-12-01

Stream channel erosion and associated habitat degradation are pervasive in streams draining urban areas in the southwestern US. The prevalence of these impacts results from the inherent sensitivity of streams in semi-arid climates to changes in flow and sediment regimes, and past inattention to management of geomorphically effective flows. Addressing this issue is difficult due to the lack of data linking ranges of flow (from small to large runoff events) to geomorphic channel response. Forty-three U. S. Geological Survey gages with record lengths greater than ~15 yrs and watershed areas less than ~250 square kilometers were used to empirically model the effects of urbanization on streams in southern California. The watersheds spanned a gradient of urban development and ranged from 0 to 23% total impervious area in 2001. With little flow control at the subdivision scale to date, most impervious area in the region is relatively well-connected to surface-drainage networks. Consequently, total impervious area was an effective surrogate for urbanization, and emerged as a significant (p < 0.05) predictor of instantaneous peak-flow rates at the 1.5- and 2-yr recurrence intervals, with decreasing significance and influence at higher return periods. For example, peak factors for a watershed with 20% imperviousness were ~10, 6, and 2 for the 1.5-, 2-, and 5-yr flows, respectively, with no discernable influence at flows greater than the 10-yr event. Most importantly with respect to geomorphic response, urbanization extent was a significant predictor of duration density functions, which integrate the magnitude and duration of mean daily discharges. This approach expands on previous scaling procedures to produce histogram-style cumulative flow duration graphs for ungaged sites based on urbanization extent and other watershed descriptors. Urbanization resulted in proportionally-longer durations of all geomorphically-effective flows, with a more pronounced effect on the durations of moderate flows. For example, an average watershed from the study domain with ~20% imperviousness could experience five times as many days of mean daily flows on the order of 100 cfs (3 cubic meters per second) and approximately three times as many days on the order of 1,000 cfs (30 cubic meters per second) relative to the undeveloped setting. Increased duration of sediment-transporting flows is a primary driver of accelerated changes in channel form that are often concurrent with urbanization throughout southern California, particularly in unconfined, fine-grained geomorphic settings. Consequently, urbanization seems to serve as a potential catalyst that can send previously functioning habitats onto degradational trajectories that are typically arrested via concrete/riprap trapezoidal flood conveyance channels with little ecological/geomorphic function.

Water table variability and runoff generation in an eroded peatland, South Pennines, UK

NASA Astrophysics Data System (ADS)

Daniels, S. M.; Agnew, C. T.; Allott, T. E. H.; Evans, M. G.

2008-10-01

SummaryHydrological monitoring in an eroded South Pennine peatland shows that persistent and frequent water table drawdowns occur at gully edge locations, defining a deeper and thicker acrotelm than is observed in intact peatlands (an erosional acrotelm). Antecedent water table elevation is a key control on the hydrological response to precipitation events, in particular runoff percent, the timing of peak discharges and maximum water table elevations. Significant discharge is generated whilst water table elevations are relatively low at gully edge locations, and this has a strong influence on flow pathways. Four characteristics of runoff response are recognised: (i) the rapid development of macropore/pipe flow at the start of the storm; (ii) peat rewetting, water table elevation increase and continued macropore/pipe flow; (iii) maximum water table elevations and peak stream discharge with throughflow occurring within the erosional acrotelm and rapid flow through the subsurface macropore/pipe network; (iv) rapidly declining water table elevations and stream flow following the cessation of rainfall. Gully edge peats provide a key linkage between the hillslope hydrological system and channel flow so that their influence on the hydrological functioning of the peatlands is disproportionate to their aerial extent within the catchment. Future climate change may lead to further degradation of the bogs and a reinforcement of the importance of erosion gullies to runoff generation and water quality.

Where does boreal stream DOC come from? - Quantifying the contribution from different landscape compartments using stable C isotope ratios.

NASA Astrophysics Data System (ADS)

Brink Bylund, J.; Bastviken, D.; Morth, C.; Laudon, H.; Giesler, R.; Buffam, I.

2007-12-01

Stable carbon isotope (δ13C) ratios are frequently used as a source tracer of e.g. organic matter (OM) produced in terrestrial versus aquatic environments. To our knowledge there has been no previous attempt to quantify the relative contribution of dissolved organic carbon (DOC) from various landscape compartments in catchments of different sizes. Here, we test to what extent δ13C values can be used also to quantify the relative contribution of DOC from wetlands/riparian zones along streams, and off stream forest habitats, respectively. We present data on spatial and temporal variability of DOC concentrations and δ13C-DOC values, during the year of 2005 in Krycklan catchment, a boreal stream network in northern Sweden. Ten stream sites, ranging from order 1 to 4, were monitored in sub catchments with different wetland coverage. Spatial variation of DOC concentration showed a weak but statistically significant relationship with wetland area, with higher concentration with increasing percent of wetland in the drainage area. During base flow the difference in δ13C-DOC values was significantly different between forest (-27.5‰) and wetland (-28.1‰). This spatial pattern disappears during spring peak flow when higher discharge flushing upper soil layer and the riparian zone on DOC in the catchments. A simple mixing model using DOC and δ13C-DOC showed that stream water DOC could be describe as a mixture of DOC coming from forest (deep) groundwater and wetland/riparian zone water. The result indicates that during spring peak flow almost all stream DOC (84-100%) is derived from wetlands and riparian zones. The wetland/riparian water dominates the stream DOC flux at all hydrological events, except for two sites, one forest dominated and one mixed catchment, where the forest groundwater dominated the DOC transport during base flow. Although the total wetland area in Krycklan catchment only represent 8.3%, it contributed, together with riparian zones, to as much as 83% of the yearly DOC transport. This study shows that there is a great potential in using stable carbon isotopes to quantify the relative contribution of DOC from various landscape compartments in catchments. Quantitative patterns are crucial for several reasons. It is for example necessary in predicting the response to global warming which will result in a changed hydrology and shifts in the relative area of the landscape compartments in boreal environments. KEY WORDS carbon isotopes; dissolved organic carbon; streams; boreal; landscape compartments; wetland; groundwater

The Role of Ecologists in Designing Rain Gardens: Enhancing Nitrate removal Performance

EPA Science Inventory

Rain gardens are vegetated surface depressions designed to receive stormwater runoff from roads, roofs, and parking lots. Stormwater infiltration through rain gardens’ sandy soils is intended to have both water quantity and quality benefits, through stream peak flow reduction and...

The role of ecologists in designing rain gardens: Enhancing nitrate removal performance

EPA Science Inventory

Rain gardens are vegetated surface depressions designed to receive stormwater runoff from roads, roofs, and parking lots. Stormwater infiltration through rain gardens’ sandy soils is intended to have both water quantity and quality benefits, through stream peak flow reduction an...

The 9 September 2010 torrential rain and flash flood in the Dragone catchment, Atrani, Amalfi Coast (Southern Italy)

NASA Astrophysics Data System (ADS)

Violante, C.; Braca, G.; Esposito, E.; Tranfaglia, G.

2015-08-01

In this paper we use a multi-hazard approach to analyse the 9 September 2010 flash-flood occurred in the Dragone basin, a 9 km2 catchment located along the Amalfi rocky coastal range, Southern Italy. In this area, alluvial-fan-flooding is the most frequent and destructive geologic hazards since Roman time. Sudden torrent of waters (flash flood) are caused by high-intensity and very localized cloudbursts of short duration inducing slope erosion and sediment delivery from slope-to-stream. The elevated bed load transport produces fast-moving hyperconcentrated flows with significant catastrophic implications for communities living at stream mouth. The 9 September 2010 rainstorm event lasted 1 h with an intensity rainfall peak nearly to 120 mm h-1. High topographic relief of the Amalfi coastal range and positive anomalies of the coastal waters conditioned the character of the convective system. Based on geological data and post-event field evidence and surveys, as well as homemade-videos, and eyewitness accounts the consequent flash-flood mobilized some 25 000 m3 of materials with a total (water and sediment) peak flow of 80 m3 s-1. The estimated peak discharge of only clear water was about 65 m3 s-1. This leads to a sediment bulking factor of 1.2 that corresponds to a flow with velocities similar to those of water during a flood.

Technique for simulating peak-flow hydrographs in Maryland

USGS Publications Warehouse

Dillow, Jonathan J.A.

1998-01-01

The efficient design and management of many bridges, culverts, embankments, and flood-protection structures may require the estimation of time-of-inundation and (or) storage of floodwater relating to such structures. These estimates can be made on the basis of information derived from the peak-flow hydrograph. Average peak-flow hydrographs corresponding to a peak discharge of specific recurrence interval can be simulated for drainage basins having drainage areas less than 500 square miles in Maryland, using a direct technique of known accuracy. The technique uses dimensionless hydrographs in conjunction with estimates of basin lagtime and instantaneous peak flow. Ordinary least-squares regression analysis was used to develop an equation for estimating basin lagtime in Maryland. Drainage area, main channel slope, forest cover, and impervious area were determined to be the significant explanatory variables necessary to estimate average basin lagtime at the 95-percent confidence interval. Qualitative variables included in the equation adequately correct for geographic bias across the State. The average standard error of prediction associated with the equation is approximated as plus or minus (+/-) 37.6 percent. Volume correction factors may be applied to the basin lagtime on the basis of a comparison between actual and estimated hydrograph volumes prior to hydrograph simulation. Three dimensionless hydrographs were developed and tested using data collected during 278 significant rainfall-runoff events at 81 stream-gaging stations distributed throughout Maryland and Delaware. The data represent a range of drainage area sizes and basin conditions. The technique was verified by applying it to the simulation of 20 peak-flow events and comparing actual and simulated hydrograph widths at 50 and 75 percent of the observed peak-flow levels. The events chosen are considered extreme in that the average recurrence interval of the selected peak flows is 130 years. The average standard errors of prediction were +/- 61 and +/- 56 percent at the 50 and 75 percent of peak-flow hydrograph widths, respectively.

Impacts of the Conversion of Forest to Arable Land and Long Term Agriculture Practices on the Water Pathways in Southern Brazil

NASA Astrophysics Data System (ADS)

Robinet, J.; Minella, J. P. G.; Schlesner, A.; Lücke, A.; Ameijeiras-Marino, Y.; Opfergelt, S.; Vanderborght, J.; Gerard, G.

2017-12-01

Changes in runoff pathways affect many environmental processes. Land use change (LUC), and more specifically forest conversion to arable land, is one of the controls of water fluxes at the hillslope or catchment scale. Still, the long term effects of forest conversion and agricultural activities in (sub-) tropical environments have been relatively understudied. Our objective was therefore to study the impact of deforestation and land degradation through agriculture on runoff pathways. We selected two small catchments with contrasting land use (agriculture vs. natural forest) in a subtropical region in the south of Brazil. Stream-, pore-, subsurface- and rainwater were monitored, sampled and analyzed for Dissolve Silicon concentration (DSi) and δ18O isotopic signature. Both forested and agricultural catchments were highly responsive to rainfall event and only 2 runoff components contributed to the stream discharge were identified: baseflow and peak flow components. The δ18O peak flow signal in the agricultural catchment was closely related to the δ18O rainfall signal. In the forested catchment, the δ18O peak flow signal was similar to a seasonally averaged signal. This suggested that most peak flow was derived from current rainfall events in the agricultural catchment, while being derived from a mixed reservoir in the forested one. The DSi of the peak flow was low in both catchments. Hence, the mixing in the forested catchment cannot have taken place in the soil matrix as the soil pore water contained high DSi concentrations. Instead, the mixing must have taken place in a reservoir with a relatively short residence time and isolated, to some extent, from the soil matrix. The dense channel network left by decayed roots in the forest soil above a clay-rich water-impeding B horizon is the most likely candidate and this was confirmed by visual observations. Contributions of other, deeper reservoirs are unlikely given the quick response time of the catchment. Dissolved fluxes at the catchment scale are therefore less likely to be strongly affected by the change in water pathways as, in both catchments, the peak flow component had low solute concentrations. Land use change effects on dissolved loads are likely to be more impacted by the change in water balance caused by forest removal, which leads to a higher water surplus.

Bedload transport associated with high stream power, Jordan River, Israel

PubMed Central

Inbar, Moshe; Schick, Asher P.

1979-01-01

During a flood of a magnitude that recurs once in 100 years, boulders up to 1700 mm in size were transported in the Jordan and Meshushim Rivers, northern Israel. Bedload discharge rates were estimated for periods of 3-72 hr of peak flow by a combination of hydrologic and geomorphic methods. Bedload transport rate is proportional to unit stream power in excess of that necessary for initial motion, raised to the power 3/2, as has been shown for data on other rivers. PMID:16592661

Chapter 13: Water and Forests

Treesearch

Graeme Lockaby; Chelsea Nagy; James M. Vose; Chelcy R. Ford; Ge Sun; Steve McNulty; Pete Caldwell; Erika Cohen; Jennifer Moore Meyers

2011-01-01

Forest conversion to agriculture or urban use consistently causes increased discharge, peak flow, and velocity of streams. Subregional differences in hydrologic responses to urbanization are substantial. Sediment, water chemistry indices, pathogens, and other substances often become more concentrated after forest conversion. If the conversion is to an urban use, the...

Changes in stream chemistry and nutrient export following a partial harvest in the Catskill Mountains, New York, USA

USGS Publications Warehouse

Wang, X.; Burns, Douglas A.; Yanai, R.D.; Briggs, R.D.; Germain, R.H.

2006-01-01

Clearcut forest harvesting typically results in large changes in stream water chemistry in northeastern North America. The effects of partial forest harvests on stream chemistry have not received as much attention, even though partial cutting is a more common forestry practice than clearcutting in this region. Changes in stream water chemistry following a partial cut are reported here from a 10 ha study catchment in a northern hardwood forest in the Catskill Mountains of southern New York, and are compared to those of a nearby 48 ha reference catchment. The lower two thirds of the treatment catchment was harvested in February-April 2002 by a shelterwood method, such that 33% of the basal area of the catchment was removed. Stream NO3-, NH4+, Ca2+, K+, and total dissolved aluminum (Alto) concentrations increased significantly after the harvest. Stream Ca2+, Mg2+ and NH4+ concentrations peaked 5 months after the initiation of the harvest, NO 3- and K+ concentrations peaked 6 months after cutting, and Alto concentrations peaked 1 year after cutting. Streamflow was not significantly affected by the harvest when compared to the flow of three nearby streams. Export of NO3- in stream water increased five-fold the year after the cut, and briefly exceeded atmospheric inputs of inorganic nitrogen during 4 months in the fall of 2002. Changes in stream NO3- and K+ concentrations were less than predicted by the relative basal area removed compared with those of a recent nearby clearcut. In contrast, changes in Ca2+, Mg 2+ and Alto concentrations were approximately proportional to basal area removal in these two cuts. Stream chemistry returned to values close to those of the pre-cut period and to reference values by early spring of 2003, just over a year after the initiation of the harvest, except for NO 3- concentrations, which remained elevated above background 18-20 months after completion of the cut.

Climatic and geomorphic controls on low flow hydrograph recession

NASA Astrophysics Data System (ADS)

Chandler, D. G.; Daley, M.; Kasaee Roodsari, B.; Shaw, S. B.; McNamara, J.

2017-12-01

Large scale operational hydrologic models should be capable of predicting seasonally low flow and stream intermittency as well as peak flow and inundation. We contrast examples of controls on low flow exerted by geomorphic and climatic setting at small catchment study sites in the Northeast and Northwest of the USA to indicate differences in hydrologic processes. Both regions accumulate winter snowpack and have an extended spring freshet, but the Reynolds Creek CZO and Dry Creek Experimental Watershed (both in Idaho mountains) experience a protracted summer drought, with occasional storms whereas precipitation free periods greater than five days are uncommon in the hilly Sleepers River (Vermont), and Yellow Barn State Forest (New York) and at Ley Creek, on a glacial plain (New York). At both Dry Creek and Reynolds Creek, headwater stream flow direction was transverse to groundwater, and below field capacity discharge was well related to either the ground water surface or corresponded to inversion of the hydraulic gradient over the depth of the soil. At all sites except Ley Creek, the headwaters became intermittent as the main tributary discharge declined, often disconnecting the surface source springs and seeps from the valley bottom stream. At the Idaho sites recession analysis for main stem was further complicated by consumptive use for irrigation and domestic wells. Modeling the recession characteristics of these various settings and across stream orders results in a variety of exponent values for power law scaling approaches that indicate the importance of site context for modeling low flow.

Stream profile analysis using a step backwater model for selected reaches in the Chippewa Creek basin in Medina, Wayne, and Summit Counties, Ohio

USGS Publications Warehouse

Straub, David E.; Ebner, Andrew D.

2011-01-01

The USGS, in cooperation with the Chippewa Subdistrict of the Muskingum Watershed Conservancy District, performed hydrologic and hydraulic analyses for selected reaches of three streams in Medina, Wayne, Stark, and Summit Counties in northeast Ohio: Chippewa Creek, Little Chippewa Creek, and River Styx. This study was done to facilitate assessment of various alternatives for mitigating flood hazards in the Chippewa Creek basin. StreamStats regional regression equations were used to estimate instantaneous peak discharges approximately corresponding to bankfull flows. Explanatory variables used in the regression equations were drainage area, main-channel slope, and storage area. Hydraulic models were developed to determine water-surface profiles along the three stream reaches studied for the bankfull discharges established in the hydrologic analyses. The HEC-RAS step-backwater hydraulic analysis model was used to determine water-surface profiles for the three streams. Starting water-surface elevations for all streams were established using normal depth computations in the HEC-RAS models. Cross-sectional elevation data, hydraulic-structure geometries, and roughness coefficients were collected in the field and (along with peak-discharge estimates) used as input for the models. Reach-averaged reductions in water-surface elevations ranged from 0.11 to 1.29 feet over the four roughness coefficient reduction scenarios.

Measurements and modeling of flow structure in the wake of a low profile wishbone vortex generator

NASA Technical Reports Server (NTRS)

Wendt, B. J.; Hingst, W. R.

1994-01-01

The results of an experimental examination of the vortex structures shed from a low profile 'wishbone' generator are presented. The vortex generator height relative to the turbulent boundary layer was varied by testing two differently sized models. Measurements of the mean three-dimensional velocity field were conducted in cross-stream planes downstream of the vortex generators. In all cases, a counter-rotating vortex pair was observed. Individual vortices were characterized by three descriptors derived from the velocity data; circulation, peak vorticity, and cross-stream location of peak vorticity. Measurements in the cross plane at two axial locations behind the smaller wishbone characterize the downstream development of the vortex pairs. A single region of stream wise velocity deficit is shared by both vortex cores. This is in contrast to conventional generators, where each core coincides with a region of velocity deficit. The measured cross-stream velocities for each case are compared to an Oseen model with matching descriptors. The best comparison occurs with the data from the larger wishbone.

Water flow pathway and the organic carbon discharge during rain storm events in a coniferous forested head watershed, Tokyo, central Japan

NASA Astrophysics Data System (ADS)

Moriizumi, Mihoko; Terajima, Tomomi

2010-05-01

The current intense discussion of the green house effect, that has been one of the main focuses on the carbon cycle in environmental systems of the earth, seems to be weakened the importance related to the effect of carbonic materials on substance movement in the aquatic environments; though it has just begun to be referred recently. Because dissolved organic carbon (DOC) in stream flows believes to play a main role of the carbon cycle in the fresh water environment, seasonal changes in DOC discharge were investigated in catchments with various scale and land use, especially in forested catchments which are one of the important sources of DOC. In order to understand the fundamental characteristics of the discharge of dissolved organic materials, stream flows, DOC, and fulvic acid like materials (FA) included in stream flows were measured in a coniferous forested head watershed. The watershed is located at the southeast edge of the Kanto mountain and is 40 km west of Tokyo with the elevation from 720 to 820 m and mean slope gradient of 38 degrees. Geology of the watershed is underlain by the sequence of mud and sand stones in Jurassic and the soil in the watershed is Cambisol (Inceptisols). The watershed composes of a dense cypress and cedar forest of 45 years old with poor understory vegetation. Observations were carried out for 6 rain storms of which the total precipitations ranged between 16.2 and 117.4 mm. The magnitude of the storms was classified into small, middle, and big events on the basis of the total precipitation of around 20, 40, and more than 70 mm. Stream flows were collected during the storm events by 1 hour interval and were passed through the 0.45 μm filters, and then the DOC concentrations in the flows were measured with a total organic carbon analyzer. The relative concentrations of fulvic acid (FA) in the flows were monitored with three dimensional excitations emission matrix fluorescence spectroscopy, because fulvic acid shows distinctive fluorescence peaks at around the excitation wave length of 340 nm and emission wave length of 440 nm. The timing of the peaks in DOC and FA occurred simultaneously or within 30 minutes prior to those in the stream flows. The relationship between DOC and stream flow showed linear correlations with various gradients in each event. However, the relationship between FA and stream flow showed the linear correlations only for the small and middle events and clockwise hysteresis relations occurred in the big storm events. The relationship between DOC and FA showed the linear correlations both for the extracted water of the shallow soil and for stream base flow composed mostly of groundwater discharge. However, the relationship in the storm flow closely distributed at that in the extracted water of the shallow soil. This thing reveals that DOC and FA were mainly flashed out from the shallow soil during the rain storm events. The quick rising and recession of the fulvic acid was likely provided by quick rain water discharge through the surface or near surface of the slope. However, the overland flow were rare in the watershed during the rain storms. This indicates that the rapid shallow subsurface flow, passed mainly through preferential flow pathways at the slope surface within the loose litter and root-permeated zone, was the main cause of the difference in discharge regimes between DOC and FA. The shallow subsurface flow may have flushed the FA in the near-surface of the soil, and then the relatively predominant discharge of DOC must have been caused during the big rain storm event.

Techniques for estimating flood-peak discharges of rural, unregulated streams in Ohio

USGS Publications Warehouse

Koltun, G.F.; Roberts, J.W.

1990-01-01

Multiple-regression equations are presented for estimating flood-peak discharges having recurrence intervals of 2, 5, 10, 25, 50, and 100 years at ungaged sites on rural, unregulated streams in Ohio. The average standard errors of prediction for the equations range from 33.4% to 41.4%. Peak discharge estimates determined by log-Pearson Type III analysis using data collected through the 1987 water year are reported for 275 streamflow-gaging stations. Ordinary least-squares multiple-regression techniques were used to divide the State into three regions and to identify a set of basin characteristics that help explain station-to- station variation in the log-Pearson estimates. Contributing drainage area, main-channel slope, and storage area were identified as suitable explanatory variables. Generalized least-square procedures, which include historical flow data and account for differences in the variance of flows at different gaging stations, spatial correlation among gaging station records, and variable lengths of station record were used to estimate the regression parameters. Weighted peak-discharge estimates computed as a function of the log-Pearson Type III and regression estimates are reported for each station. A method is provided to adjust regression estimates for ungaged sites by use of weighted and regression estimates for a gaged site located on the same stream. Limitations and shortcomings cited in an earlier report on the magnitude and frequency of floods in Ohio are addressed in this study. Geographic bias is no longer evident for the Maumee River basin of northwestern Ohio. No bias is found to be associated with the forested-area characteristic for the range used in the regression analysis (0.0 to 99.0%), nor is this characteristic significant in explaining peak discharges. Surface-mined area likewise is not significant in explaining peak discharges, and the regression equations are not biased when applied to basins having approximately 30% or less surface-mined area. Analyses of residuals indicate that the equations tend to overestimate flood-peak discharges for basins having approximately 30% or more surface-mined area. (USGS)

Coupled three-layer model for turbulent flow over large-scale roughness: On the hydrodynamics of boulder-bed streams

NASA Astrophysics Data System (ADS)

Pan, Wen-hao; Liu, Shi-he; Huang, Li

2018-02-01

This study developed a three-layer velocity model for turbulent flow over large-scale roughness. Through theoretical analysis, this model coupled both surface and subsurface flow. Flume experiments with flat cobble bed were conducted to examine the theoretical model. Results show that both the turbulent flow field and the total flow characteristics are quite different from that in the low gradient flow over microscale roughness. The velocity profile in a shallow stream converges to the logarithmic law away from the bed, while inflecting over the roughness layer to the non-zero subsurface flow. The velocity fluctuations close to a cobble bed are different from that of a sand bed, and it indicates no sufficiently large peak velocity. The total flow energy loss deviates significantly from the 1/7 power law equation when the relative flow depth is shallow. Both the coupled model and experiments indicate non-negligible subsurface flow that accounts for a considerable proportion of the total flow. By including the subsurface flow, the coupled model is able to predict a wider range of velocity profiles and total flow energy loss coefficients when compared with existing equations.

Impact of Air Injection on Jet Noise

NASA Technical Reports Server (NTRS)

Henderson, Brenda; Norum, Tom

2007-01-01

The objective of this viewgraph presentation is to review the program to determine impact of core fluidic chevrons on noise produced by dual stream jets (i.e., broadband shock noise - supersonic, and mixing noise - subsonic and supersonic). The presentation reviews the sources of jet noise. It shows designs of Generation II Fluidic Chevrons. The injection impacts shock structure and stream disturbances through enhanced mixing. This may impact constructive interference between acoustic sources. The high fan pressures may inhibit mixing produced by core injectors. A fan stream injection may be required for better noise reduction. In future the modification of Gen II nozzles to allow for some azimuthal control: will allow for higher mass flow rates and will allow for shallower injection angles A Flow field study is scheduled for spring, 2008 The conclusions are that injection can reduce well-defined shock noise and injection reduces mixing noise near peak jet noise angle

Storms and flooding in California in December 2005 and January 2006 - a preliminary assessment

USGS Publications Warehouse

Parrett, Charles; Hunrichs, Richard A.

2006-01-01

A series of storms beginning before Christmas 2005 and ending after New Year's Day 2006 produced significant runoff over much of northern California. The storms resulted in an estimated $300 million in damages and Federal disaster declarations in 10 counties. Several precipitation stations in the Sierra Nevada had precipitation totals greater than 20 inches for the period December 24 through January 3, and several stations in the Coastal Range had precipitation totals greater than 18 inches. The peak stream discharges resulting from the storms in the north coast area generally had recurrence intervals in the 10- to 25-year range, although the recurrence interval for peak discharge at one station on Sonoma Creek near Agua Caliente was greater than 100 years. In the San Francisco Bay area, peak discharges also generally had recurrence intervals in the 10- to 25-year range. Further south along the central coast and in southern California, peak discharges had smaller recurrence intervals, in the 2- to 5-year range. Upper Sacramento River tributaries draining from the west had peak flows with recurrence intervals in the 2- to 5-year range, whereas upper tributaries draining from the east side had recurrence intervals in the 5- to 10-year range. Further south, Sacramento River tributaries such as the Yuba and American Rivers had peak discharges with recurrence intervals in the 10- to 25-year range. On the east side of the central Sierra around Lake Tahoe, peak discharges had recurrence intervals in the 10- to 25-year range. Further south in the Sierra, streams draining into the San Joaquin River Basin had flows with recurrence intervals ranging from 2 to 5 years.

TRADABLE CREDITS FOR STORM WATER VOLUME: AN ALTERNATIVE APPROACH FOR SUSTAINABLE URBAN WATERSHED MANAGEMENT

EPA Science Inventory

The increased storm water runoff rate and volume caused by urbanization, and their detrimental effects on stream habitat and morphology, is well documented. In most cases, current storm water management policies are focused on attenuating peak flow rates. While these policies may...

Testing wetland axioms at a watershed scale: Case studies of the aggregate hydrologic effects of non-adjacent wetlands

EPA Science Inventory

Wetlands not adjacent to streams (i.e. “non-adjacent wetlands”) are hypothesized to affect downgradient hydrology in a number of ways. Non-adjacent wetlands may, for example, attenuate peak flows, serve as focal points for groundwater recharge, and decrease streamflow...

Digital-map grids of mean-annual precipitation for 1961-90, and generalized skew coefficients of annual maximum streamflow for Oklahoma

USGS Publications Warehouse

Rea, A.H.; Tortorelli, R.L.

1997-01-01

This digital report contains two digital-map grids of data that were used to develop peak-flow regression equations in Tortorelli, 1997, 'Techniques for estimating peak-streamflow frequency for unregulated streams and streams regulated by small floodwater retarding structures in Oklahoma,' U.S. Geological Survey Water-Resources Investigations Report 97-4202. One data set is a grid of mean annual precipitation, in inches, based on the period 1961-90, for Oklahoma. The data set was derived from the PRISM (Parameter-elevation Regressions on Independent Slopes Model) mean annual precipitation grid for the United States, developed by Daly, Neilson, and Phillips (1994, 'A statistical-topographic model for mapping climatological precipitation over mountainous terrain:' Journal of Applied Meteorology, v. 33, no. 2, p. 140-158). The second data set is a grid of generalized skew coefficients of logarithms of annual maximum streamflow for Oklahoma streams less than or equal to 2,510 square miles in drainage area. This grid of skew coefficients is taken from figure 11 of Tortorelli and Bergman, 1985, 'Techniques for estimating flood peak discharges for unregulated streams and streams regulated by small floodwater retarding structures in Oklahoma,' U.S. Geological Survey Water-Resources Investigations Report 84-4358. To save disk space, the skew coefficient values have been multiplied by 100 and rounded to integers with two significant digits. The data sets are provided in an ASCII grid format.

Using U-Pb Detrital Zircon Geochronology to Study Ice Streams in the Weddell Sea Embayment, Antarctica

NASA Astrophysics Data System (ADS)

Agrios, L.; Licht, K.; Hemming, S. R.; Williams, T.

2016-12-01

Till from major ice streams of the Weddell Sea Embayment contain detrital zircons with distinct U-Pb age populations that can be used as a provenance tool to better understand ice stream dynamics. The ice streams in this study include the Foundation Ice Stream, and Academy, Slessor, and Recovery glaciers, all of which drain ice from the continent's interior into the Weddell Sea. Characterizing the U-Pb detrital zircon ages in till and rocks will (1) provide the zircon provenance signatures of the material carried by the ice stream - when these signatures are found in LGM and older deposits downstream they can enable interpretation of past ice flow history; and (2) constrain ice-covered upstream bedrock geology that supplies the till carried by ice streams and glaciers. U-Pb ages of detrital zircons were measured in 21 samples of onshore till, erratics, and bedrock of potential source rocks. Grains were analyzed by LA-ICPMS at the University of Arizona (n=300). Relative probability U-Pb age density plots of till in moraines along the Foundation Ice Stream and Academy Glacier show prominent peaks at 500-530 and 615-650 Ma, which overlap with the timing of the Ross and Pan-African orogenies. Zircon ages of 1000-1095 Ma are also present. Local bedrock in the Patuxent Range has the most prominent peak at 510 Ma, suggesting the till is predominantly derived from local Patuxent Formation. However, local bedrock also has fewer grains at 1030 Ma which suggests that this age population is carried in the till as well. Prominent peaks in U-Pb ages from till transported by the Recovery Glacier are 530, 635, 1610 and 1770 Ma. Bedrock of this area contains similar age peaks, with the exception of the 635 Ma peak, suggesting that this ice stream is carrying a signature from an unexposed source of this age completely buried by ice. The Slessor Glacier carries zircons with prominent populations at 1710 and 2260-2420 Ma, which overlap with a high-grade metamorphic event in the Shackleton Range between 1710-1680 Ma. In order to gain the offshore signature of ice streams, these data will be compared to 40Ar/39Ar hornblende and biotite thermochronological data, and U-Pb geochronology data from subglacial till and proximal glaciomarine sediment from existing core sites located at the edge of the Ronne-Filchner Ice Shelf.

Generalized Skew Coefficients of Annual Peak Flows for Rural, Unregulated Streams in West Virginia

USGS Publications Warehouse

Atkins, John T.; Wiley, Jeffrey B.; Paybins, Katherine S.

2009-01-01

Generalized skew was determined from analysis of records from 147 streamflow-gaging stations in or near West Virginia. The analysis followed guidelines established by the Interagency Advisory Committee on Water Data described in Bulletin 17B, except that stations having 50 or more years of record were used instead of stations with the less restrictive recommendation of 25 or more years of record. The generalized-skew analysis included contouring, averaging, and regression of station skews. The best method was considered the one with the smallest mean square error (MSE). MSE is defined as the following quantity summed and divided by the number of peaks: the square of the difference of an individual logarithm (base 10) of peak flow less the mean of all individual logarithms of peak flow. Contouring of station skews was the best method for determining generalized skew for West Virginia, with a MSE of about 0.2174. This MSE is an improvement over the MSE of about 0.3025 for the national map presented in Bulletin 17B.

Designing ecological flows to gravely braided rivers in alpine environments

NASA Astrophysics Data System (ADS)

Egozi, R.; Ashmore, P.

2009-04-01

Designing ecological flows in gravelly braided streams requires estimating the channel forming discharge in order to maintain the braided reach physical (allocation of flow and bed load) and ecological (maintaining the habitat diversity) functions. At present, compared to single meander streams, there are fewer guiding principles for river practitioners that can be used to manage braided streams. Insight into braiding morphodynamics using braiding intensity indices allows estimation of channel forming discharge. We assess variation in braiding intensity by mapping the total number of channels (BIT) and the number of active (transporting bed load) channels (BIA) at different stages of typical diurnal melt-water hydrographs in a pro-glacial braided river, Sunwapta River, Canada. Results show that both BIA and BIT vary with flow stage but over a limited range of values. Furthermore, maximum BIT occurs below peak discharge. At this stage there is a balance between channel merging from inundation and occupation of new channels as the stage rises. This stage is the channel forming discharge because above this stage the existing braided pattern cannot discharge the volume of water without causing morphological changes (e.g., destruction of bifurcations, channel avulsion). Estimation of the channel forming discharge requires a set of braiding intensity measurements over a range of flow stages. The design of ecological flows must take into consideration flow regime characteristics rather than just the channel forming discharge magnitude.

Addressing the Old Water Paradox using tritium

NASA Astrophysics Data System (ADS)

Cartwright, Ian; Morgenstern, Uwe

2017-04-01

The paradox that much of the water that contributes to streams during high flow events appears to be derived from relatively old stores in catchments has been of interest to hydrogeologists for several decades. It is a common observation that stream chemistry varies less than would be expected if simple dilution of groundwater inflows by event water occurred during storm events. However, it is not clear to what extent this observation reflects displacement of water from the soils or the regolith vs. enhanced discharge of older groundwater into the stream. Here we use tritium in conjunction with major ion and stable isotope tracers to assess the sources of water in high flow events in streams in southeast Australia. The concentrations of most of the major ions and EC values either remained relatively constant during the high flow events or displayed non-systematic variations with respect to flow. Oxygen isotopes do vary systematically during the events, but the magnitude of the variation is <1‰.. By contrast, there is a notable systematic increase in the nitrate concentrations and a decrease in silica concentrations during the events. Tritium activities increased from 1.4 to 1.5 TU to up to 2.4 TU close to the peak in streamflow and then decline over several days to pre-high flow levels. The peak tritium activities in the stream are lower than the tritium activity of the rainfall that generated the high flow events (2.7 to 2.8 TU) but within the range of tritium activities commonly recorded in soil water in southeast Australia (2.0 to 2.6 TU). The combined geochemical data imply that there is significant input from water stores other than groundwater during the high flow events. This is most likely to include a significant component of water displaced from the soils or regolith that typically has a residence time of 1 to 5 years. The major ion geochemistry of this water, especially its nitrate concentrations, is distinct from both groundwater and rainfall reflecting biogeochemical reactions in the soil zone/regolith. More generally, this study illustrates that since catchments contain multiple stores of water, including intermediate stores such as soil water, interflow, and water in the regolith, a multi-tracer approach is required to apportion the contribution of water from these stores during high flow events. Most of the major ions and EC were not useful in determining the changing water stores and the variation in stable isotopes was minor. Tritium provides the opportunity to directly assess how the average residence time of water varies across the flow event and through this address some aspects of the old water paradox.

The 9 September 2010 torrential rain and flash flood in the Dragone catchment, Atrani, Amalfi Coast (southern Italy)

NASA Astrophysics Data System (ADS)

Violante, C.; Braca, G.; Esposito, E.; Tranfaglia, G.

2016-02-01

In this paper we use a multi-hazard approach to analyse the 9 September 2010 flash flood in the Dragone basin, a 9 km2 catchment located along the Amalfi rocky coastal range, southern Italy. In this area, alluvial fan flooding has been the most frequent and destructive geologic hazard since Roman times. Sudden torrents of water (flash floods) are caused by high-intensity and very localized cloudbursts of short duration, inducing slope erosion and sediment delivery from slope to stream. The elevated bed load transport produces fast-moving hyperconcentrated flows with significant catastrophic implications for communities living at the stream mouth. The 9 September 2010 rainstorm event lasted 1 h with an intensity rainfall peak of nearly 120 mm h-1. High topographic relief of the Amalfi coastal range and positive anomalies of the coastal waters conditioned the character of the convective system. Based on geological data and post-event field evidence and surveys, as well as homemade videos and eyewitness accounts, it is reported that the flash flood mobilized some 25 000 m3 of materials with a total (water and sediment) peak flow of 80 m3 s-1. The estimated peak discharge of only clear water was about 65 m3 s-1. This leads to a sediment bulking factor of 1.2 that corresponds to a flow with velocities similar to those of water during a flood.

Rainfall-Runoff Dynamics Following Wildfire in Mountainous Headwater Catchments, Alberta, Canada.

NASA Astrophysics Data System (ADS)

Williams, C.; Silins, U.; Bladon, K. D.; Martens, A. M.; Wagner, M. J.; Anderson, A.

2015-12-01

Severe wildfire has been shown to increase the magnitude and advance the timing of rainfall-generated stormflows across a range of hydro-climate regions. Loss of canopy and forest floor interception results in increased net precipitation which, along with the removal of forest organic layers and increased shorter-term water repellency, can result in strongly increased surface flow pathways and efficient routing of precipitation to streams. These abrupt changes have the potential to exacerbate flood impacts and alter the timing of runoff delivery to streams. However, while these effects are well documented in drier temperate mountain regions, changes in post-fire rainfall-runoff processes are less well understood in colder, more northern, snowfall dominated regimes. The objectives of this study are to explore longer term precipitation and runoff dynamics of burned and unburned (reference) watersheds from the Southern Rockies Watershed Project (SRWP) after the 2003 Lost Creek wildfire in the front-range Rocky Mountains of southwestern Alberta, Canada. Streamflow and precipitation were measured in 5 watersheds (3.7 - 10.4 km2) for 10 years following the wildfire (2005-2014). Measurements were collected from a dense network of meteorological and hydrometric stations. Stormflow volume, peak flow, time to peak flow, and total annual streamflow were compared between burned and reference streams. Event-based data were separated into 3 post-fire periods to detect changes in rainfall-runoff dynamics as vegetation regenerated. Despite large increases in post-fire snowpacks and net summer rainfall, rainfall-generated runoff from fire-affected watersheds was not large in comparison to that reported from more temperate snowfall-dominated Rocky Mountain hydrologic settings. High proportions of groundwater contribution to annual runoff regimes (as opposed to surface flow pathways) and groundwater storage were likely contributors to greater watershed resistance to wildfire effects in these northern Rocky Mountain catchments.

Mapping debris flow susceptibility using analytical network process in Kodaikkanal Hills, Tamil Nadu (India)

NASA Astrophysics Data System (ADS)

Sujatha, Evangelin Ramani; Sridhar, Venkataramana

2017-12-01

Rapid debris flows, a mixture of unconsolidated sediments and water travelling at speeds > 10 m/s are the most destructive water related mass movements that affect hill and mountain regions. The predisposing factors setting the stage for the event are the availability of materials, type of materials, stream power, slope gradient, aspect and curvature, lithology, land use and land cover, lineament density, and drainage. Rainfall is the most common triggering factor that causes debris flow in the Palar subwatershed and seismicity is not considered as it is a stable continental region and moderate seismic zone. Also, there are no records of major seismic activities in the past. In this study, one of the less explored heuristic methods known as the analytical network process (ANP) is used to map the spatial propensity of debris flow. This method is based on top-down decision model and is a multi-criteria, decision-making tool that translates subjective assessment of relative importance to weights or scores and is implemented in the Palar subwatershed which is part of the Western Ghats in southern India. The results suggest that the factors influencing debris flow susceptibility in this region are the availability of material on the slope, peak flow, gradient of the slope, land use and land cover, and proximity to streams. Among all, peak discharge is identified as the chief factor causing debris flow. The use of micro-scale watersheds demonstrated in this study to develop the susceptibility map can be very effective for local level planning and land management.

Relation between flows and dissolved oxygen in the Roanoke River between Roanoke Rapids Dam and Jamesville, North Carolina, 2005-2009

USGS Publications Warehouse

Wehmeyer, Loren L.; Wagner, Chad R.

2011-01-01

The relation between dam releases and dissolved-oxygen concentration, saturation and deficit, downstream from Roanoke Rapids Dam in North Carolina was evaluated from 2005 to 2009. Dissolved-oxygen data collected at four water-quality monitoring stations downstream from Roanoke Rapids Dam were used to determine if any statistical relations or discernible quantitative or qualitative patterns linked Roanoke River in-stream dissolved-oxygen levels to hydropower peaking at Roanoke Rapids Dam. Unregulated tributaries that inundate and drain portions of the Roanoke River flood plain are crucial in relation to in-stream dissolved oxygen. Hydropower peaking from 2005 to 2009 both inundated and drained portions of the flood plain independently of large storms. The effects of these changes in flow on dissolved-oxygen dynamics are difficult to isolate, however, because of (1) the variable travel time for water to move down the 112-mile reach of the Roanoke River from Roanoke Rapids Dam to Jamesville, North Carolina, and (2) the range of in-situ conditions, particularly inundation history and water temperature, in the flood plain. Statistical testing was conducted on the travel-time-adjusted hourly data measured at each of the four water-quality stations between May and November 2005-2009 when the weekly mean flow was 5,000-12,000 cubic feet per second (a range when Roanoke Rapids Dam operations likely affect tributary and flood-plain water levels). Results of this statistical testing indicate that at the 99-percent confidence interval dissolved-oxygen levels downstream from Roanoke Rapids Dam were lower during peaking weeks than during non-peaking weeks in three of the five years and higher in one of the five years; no data were available for weeks with peaking in 2007. For the four years of statistically significant differences in dissolved oxygen between peaking and non-peaking weeks, three of the years had statistically signficant differences in water temperature. Years with higher water temperature during peaking had lower dissolved oxygen during peaking. Only 2009 had no constistent statistically significant water-temperature difference at all sites, and dissolved-oxygen levels downstream from Roanoke Rapids Dam during peaking weeks that year were lower than during non-peaking weeks. Between 2005 and 2009, daily mean dissolved-oxygen concentrations below the State standard occurred during only 1 of the 17 (6 percent) peaking weeks, with no occurrence of instantaneous dissolved-oxygen concentrations below the State standard. This occurrence was during a 9-day period in July 2005 when the daily maximum air temperatures approached or exceeded 100 degrees Fahrenheit, and the draining of the flood plains from peaking operations was followed by consecutive days of low flows.

Methods for determining magnitude and frequency of floods in California, based on data through water year 2006

USGS Publications Warehouse

Gotvald, Anthony J.; Barth, Nancy A.; Veilleux, Andrea G.; Parrett, Charles

2012-01-01

Methods for estimating the magnitude and frequency of floods in California that are not substantially affected by regulation or diversions have been updated. Annual peak-flow data through water year 2006 were analyzed for 771 streamflow-gaging stations (streamgages) in California having 10 or more years of data. Flood-frequency estimates were computed for the streamgages by using the expected moments algorithm to fit a Pearson Type III distribution to logarithms of annual peak flows for each streamgage. Low-outlier and historic information were incorporated into the flood-frequency analysis, and a generalized Grubbs-Beck test was used to detect multiple potentially influential low outliers. Special methods for fitting the distribution were developed for streamgages in the desert region in southeastern California. Additionally, basin characteristics for the streamgages were computed by using a geographical information system. Regional regression analysis, using generalized least squares regression, was used to develop a set of equations for estimating flows with 50-, 20-, 10-, 4-, 2-, 1-, 0.5-, and 0.2-percent annual exceedance probabilities for ungaged basins in California that are outside of the southeastern desert region. Flood-frequency estimates and basin characteristics for 630 streamgages were combined to form the final database used in the regional regression analysis. Five hydrologic regions were developed for the area of California outside of the desert region. The final regional regression equations are functions of drainage area and mean annual precipitation for four of the five regions. In one region, the Sierra Nevada region, the final equations are functions of drainage area, mean basin elevation, and mean annual precipitation. Average standard errors of prediction for the regression equations in all five regions range from 42.7 to 161.9 percent. For the desert region of California, an analysis of 33 streamgages was used to develop regional estimates of all three parameters (mean, standard deviation, and skew) of the log-Pearson Type III distribution. The regional estimates were then used to develop a set of equations for estimating flows with 50-, 20-, 10-, 4-, 2-, 1-, 0.5-, and 0.2-percent annual exceedance probabilities for ungaged basins. The final regional regression equations are functions of drainage area. Average standard errors of prediction for these regression equations range from 214.2 to 856.2 percent. Annual peak-flow data through water year 2006 were analyzed for eight streamgages in California having 10 or more years of data considered to be affected by urbanization. Flood-frequency estimates were computed for the urban streamgages by fitting a Pearson Type III distribution to logarithms of annual peak flows for each streamgage. Regression analysis could not be used to develop flood-frequency estimation equations for urban streams because of the limited number of sites. Flood-frequency estimates for the eight urban sites were graphically compared to flood-frequency estimates for 630 non-urban sites. The regression equations developed from this study will be incorporated into the U.S. Geological Survey (USGS) StreamStats program. The StreamStats program is a Web-based application that provides streamflow statistics and basin characteristics for USGS streamgages and ungaged sites of interest. StreamStats can also compute basin characteristics and provide estimates of streamflow statistics for ungaged sites when users select the location of a site along any stream in California.

Hydrologic flow paths control dissolved organic carbon fluxes and metabolism in an Alpine stream hyporheic zone

NASA Astrophysics Data System (ADS)

Battin, Tom J.

1999-10-01

The objective of the present paper was to link reach-scale streambed reactive uptake of dissolved organic carbon (DOC) and dissolved oxygen (DO) to subsurface flow paths in an alpine stream (Oberer Seebach (OSB)). The topography adjacent to the stream channel largely determined flow paths, with shallow hillslope groundwater flowing beneath the stream and entering the alluvial groundwater at the opposite bank. As computed from hydrometric data, OSB consistently lost stream water to groundwater with fluxes out of the stream averaging 943 ± 47 and 664 ± 45 L m-2 h-1 at low (Q < 600 L s-1) and high (Q > 600 L s-1) flow, respectively. Hydrometric segregation of streambed fluxes and physicochemical mixing analysis indicated that stream water was the major input component to the streambed with average contributions of 70-80% to the hyporheic zone (i.e., the subsurface zone where shallow groundwater and stream water mix). Surface water was also the major source of DOC with 0.512 ± 0.043 mg C m-2 h-1 to the streambed. The DOC flux from shallow riparian groundwater was lower (0.309 ± 0.071 mg C m-2 h-1) and peaked in autumn with 1.011 mg C m-2 h-1. I computed the relative proportion of downstream discharge through the streambed as the ratio of the downstream length (Ssw) a stream water parcel travels before entering the streambed to the downstream length (Shyp) a streambed water parcel travels before returning to the stream water. The relative streambed DOC retention efficiency, calculated as (input-output)/input of interstitial DOC, correlated with the proportion (Ssw/Shyp) of downstream discharge (r2 = 0.76, p = 0.006). Also, did the streambed metabolism (calculated as DO uptake from mass balance) decrease with low subsurface downstream routing, whereas elevated downstream discharge through the streambed stimulated DO uptake (r2 = 0.69, p = 0.019)? Despite the very short DOC turnover times (˜0.05 days, calculated as mean standing stock/annual input) within the streambed, the latter constitutes a net sink of DOC (˜14 mg C m-2 h-1). Along with high standing stocks of sediment associated particulate organic carbon, these results suggest microbial biofilms as the major retention and storage site of DOC in an alpine stream where large hydrologic exchange controls DOC fluxes.

THE ECOLOGICAL EFFECTIVENESS OF PONDS AND WETLANDS AS "BEST MANAGEMENT PRACTICES (BMPS)" FOR STREAMS IN DEVELOPING LANDSCAPES

EPA Science Inventory

Ponds and constructed wetlands, also referred to as detention/retention basins, have a long history as best management practices (BMPs) used to mitigate the impacts of stormwater runoff from developed lands on receiving waters. Initially designed for flood control by peak flow at...

Application of remotely sensed land-use information to improve estimates of streamflow characteristics, volume 8. [Maryland, Virginia, and Delaware

NASA Technical Reports Server (NTRS)

Pluhowski, E. J. (Principal Investigator)

1977-01-01

The author has identified the following significant results. Land use data derived from high altitude photography and satellite imagery were studied for 49 basins in Delaware, and eastern Maryland and Virginia. Applying multiple regression techniques to a network of gaging stations monitoring runoff from 39 of the basins, demonstrated that land use data from high altitude photography provided an effective means of significantly improving estimates of stream flow. Forty stream flow characteristic equations for incorporating remotely sensed land use information, were compared with a control set of equations using map derived land cover. Significant improvement was detected in six equations where level 1 data was added and in five equations where level 2 information was utilized. Only four equations were improved significantly using land use data derived from LANDSAT imagery. Significant losses in accuracy due to the use of remotely sensed land use information were detected only in estimates of flood peaks. Losses in accuracy for flood peaks were probably due to land cover changes associated with temporal differences among the primary land use data sources.

Crest-stage gaging stations in Oregon: a compilation of peak data collected from October 1952 to September 1974

USGS Publications Warehouse

Friday, John

1974-01-01

A crest-stage gaging station provides an excellent means for determining peak water-surface elevations at a selected location on a stream channel. When related to streamflow, these data provide hydrologists with a knowledge of the flood experience of a drainage basin. If an adequate flood history is known, it is possible to estimate the probable magnitude and frequency of floods likely to occur in that basin, and this information is a valuable asset to anyone who must estimate design floods at proposed drainage structures. However, most design problems involve estimating peak flows on ungaged streams. This is difficult because the rate of storm runoff is not the same in all basins due to the influence of various basin characteristics which can either assist or retard the runoff. The crest-stage gaging program in Oregon is designed to provide a representative sampliing of peak flows at basins having a wide range in characteristics. Then, after sufficient data are collected, a statistical analysis can be made which will provide a means for estimating design floods at ungaged sites on the basis of known basin characteristics.This report is one of a series presenting a compilation of peak data collected at 232 crest-stage gaging stations in Oregon. The collection and publication of these data are made possible through mutual funding by State and Federal agencies. The Geological Survey, the Oregon State Highway Commission, the Federal Highway Administration, and the Bureau of Land Management are currently supporting 160 active crest-stage stations in Oregon.

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.

A Physically Based Distributed Hydrologic Model with a no-conventional terrain analysis

NASA Astrophysics Data System (ADS)

Rulli, M.; Menduni, G.; Rosso, R.

2003-12-01

A physically based distributed hydrological model is presented. Starting from a contour-based terrain analysis, the model makes a no-conventional discretization of the terrain. From the maximum slope lines, obtained using the principles of minimum distance and orthogonality, the models obtains a stream tubes structure. The implemented model automatically can find the terrain morphological characteristics, e.g. peaks and saddles, and deal with them respecting the stream flow. Using this type of discretization, the model divides the elements in which the water flows in two classes; the cells, that are mixtilinear polygons where the overland flow is modelled as a sheet flow and channels, obtained by the interception of two or more stream tubes and whenever surface runoff occurs, the surface runoff is channelised. The permanent drainage paths can are calculated using one of the most common methods: threshold area, variable threshold area or curvature. The subsurface flow is modelled using the Simplified Bucket Model. The model considers three type of overland flow, depending on how it is produced:infiltration excess;saturation of superficial layer of the soil and exfiltration of sub-surface flow from upstream. The surface flow and the subsurface flow across a element are routed according with the mono-dimensional equation of the kinematic wave. The also model considers the spatial variability of the channels geometry with the flow. The channels have a rectangular section with length of the base decreasing with the distance from the outlet and depending on a power of the flow. The model was tested on the Rio Gallina and Missiaga catchments and the results showed model good performances.

Time-Scales of Storm Flow Response in the Stream and Hyporheic Zone of a Small, Steep Forested Catchment - Contrasting the Potential Contributions from the Hillslope, Riparian-Hyporheic Zones, and the Stream Channel

NASA Astrophysics Data System (ADS)

Wondzell, S. M.; Corson-rikert, H.; Haggerty, R.

2016-12-01

Storm-flow responses of small catchments are widely studied to identify water sources and mechanisms routing water through catchments. These studies typically observe rapid responses to rainfall with peak concentrations of many chemical constituents occurring on rising leg of the hydrograph. To explain this, some conceptual models suggest that stream water early in storm periods is dominated by riparian water sources with hillslope water sources dominating later in the storm. We examined changes in both stream and hyporheic water chemistry during a small, autumn storm in a forested mountain catchment to test this conceptual model. Our study site was located in WS01 at the H.J. Andrews Experimental Forest, in Oregon, USA. The watershed has a narrow valley floor, always less than 15 m wide and occasionally interrupted by narrow, constrained bedrock sections. The valley floor has a longitudinal gradient of approximately 14%. Hyporheic water tends to flow parallel the valley axis and flow paths change little with changes in stream discharge, even during storm events. A well network is located in a 30-m reach near the bottom of the watershed. We sampled the stream, 9 hyporheic wells, and a hillslope well for DOC, DIC, Cl-, and NO3- during the storm. As expected, concentrations of DOC and NO3- increased rapidly on the rising leg of the hydrograph in both the stream and the hyporheic wells. However, the stream always had higher concentrations of DOC, and lower concentrations of NO3-, than did either the hillslope well or the hyporheic wells. These data suggest that the riparian/hyporheic zone is not a likely source of water influencing stream water chemistry on the rising leg of the hydrograph. These data agree with median travel time estimates of water flowing along hyporheic flow paths - it takes many 10s of hours for water to move from the riparian/hyporheic zone to the stream - a time scale that is far too slow to explain the rapid changes observed on the rising leg of the hydrograph. These data suggest that much of the early storm responses in stream chemistry may be generated by in-channel processes, or processes occurring in the shallow streambed with very short hyporheic residence times; the influence of the riparian zone, most of the hyporheic zone, or hillslopes must occur much later in the storm event.

Storm and flood of July 5, 1989, in northern New Castle County, Delaware

USGS Publications Warehouse

Paulachok, G.N.; Simmons, R.H.; Tallman, A.J.

1995-01-01

On July 5, 1989, intense rainfall from the remnants of Tropical Storm Allison caused severe flooding in northern New Castle County, Delaware. The flooding claimed three lives, and damage was estimated to be $5 million. Flood conditions were aggravated locally by rapid runoff from expansive urban areas. Record- breaking floods occurred on many streams in northern New Castle County. Peak discharges at three active, continuous-record streamflow-gaging stations, one active crest-stage station, and at two discontinued streamflow-gaging stations exceeded previously recorded maximums. Estimated recurrence intervals for peak flow at the three active, continuous-record streamflow stations exceeded 100 years. The U.S. Geological Survey conducted comprehensive post-flood surveys to determine peak water-surface elevations that occurred on affected streams and their tributaries during the flood of July 5, 1989. Detailed surveys were performed near bridge crossings to provide additional information on the extent and severity of the flooding and the effects of hydraulic constrictions on floodwaters.

Channel infiltration from floodflows along the Pawnee River and its tributaries, west-central Kansas

USGS Publications Warehouse

Gillespie, James B.; Perry, C.A.

1988-01-01

Most of the streams is west-central Kansas are ephemeral. Natural recharge to the alluvial aquifers underlying these streams occurs during periods of storm runoff in the ephemeral channels. Proposed flood-retarding structures within the basin will alter the downstream runoff characteristics in these channels by reducing the peak flow and increasing the flow duration. Information concerning channel-infiltration rate, unsaturated and saturated flow, and lithology of the unsaturated zone as related to stream stage and duration was collected along the Pawnee River and its tributaries to determine the effects of the flood-retarding structures. The infiltration rate on ephemeral streams was determined at five sites within the Pawnee River Basin. Tests were conducted in channel infiltrometers constructed by isolating a section of channel with two plastic-lined wooden cofferdams. At two of the sites, perched groundwater mounds intersected the bottom of the channel and reduced the infiltration rate. At two other sites where the perched groundwater mounds did not reach the bottom of the channel, the infiltration rate was directly proportional to the stage. Comparison of infiltration from simulated controlled and uncontrolled floodflows at the five sites indicated an average increase of about 2% with the controlled floodflow. Cumulative infiltration for these simulations ranged from 0.5 to 14.8 acre-ft/mi of channel. (USGS)

Estimation of methane concentrations and loads in groundwater discharge to Sugar Run, Lycoming County, Pennsylvania

USGS Publications Warehouse

Heilweil, Victor M.; Risser, Dennis W.; Conger, Randall W.; Grieve, Paul L.; Hynek, Scott A.

2014-01-01

A stream-sampling study was conducted to estimate methane concentrations and loads in groundwater discharge to a small stream in an active shale-gas development area of northeastern Pennsylvania. Grab samples collected from 15 streams in Bradford, Lycoming, Susquehanna, and Tioga Counties, Pa., during a reconnaissance survey in May and June 2013 contained dissolved methane concentrations ranging from less than the minimum reporting limit (1.0) to 68.5 micrograms per liter (µg/L). The stream-reach mass-balance method of estimating concentrations and loads of methane in groundwater discharge was applied to a 4-kilometer (km) reach of Sugar Run in Lycoming County, one of the four streams with methane concentrations greater than or equal to 5 µg/L. Three synoptic surveys of stream discharge and methane concentrations were conducted during base-flow periods in May, June, and November 2013. Stream discharge at the lower end of the reach was about 0.10, 0.04, and 0.02 cubic meters per second, respectively, and peak stream methane concentrations were about 20, 67, and 29 µg/L. In order to refine estimated amounts of groundwater discharge and locations where groundwater with methane discharges to the stream, the lower part of the study reach was targeted more precisely during the successive studies, with approximate spacing between stream sampling sites of 800 meters (m), 400 m, and 200 m, in May, June, and November, respectively. Samples collected from shallow piezometers and a seep near the location of the peak methane concentration measured in streamwater had groundwater methane concentrations of 2,300 to 4,600 µg/L. These field data, combined with one-dimensional stream-methane transport modeling, indicate groundwater methane loads of 1.8 ±0.8, 0.7 ±0.3, and 0.7 ±0.2 kilograms per day, respectively, discharging to Sugar Run. Estimated groundwater methane concentrations, based on the transport modeling, ranged from 100 to 3,200 µg/L. Although total methane load and the uncertainty in calculated loads both decreased with lower streamflow conditions and finer-resolution sampling in June and November, the higher loads during May could indicate seasonal variability in base flow. This is consistent with flowmeter measurements indicating that there was less inflow occurring at lower streamflow conditions during June and November.

Surface-water and groundwater interactions in an extensively mined watershed, upper Schuylkill River, Pennsylvania, USA

USGS Publications Warehouse

Cravotta, Charles A.; Goode, Daniel J.; Bartles, Michael D.; Risser, Dennis W.; Galeone, Daniel G.

2014-01-01

Streams crossing underground coal mines may lose flow, while abandoned mine drainage (AMD) restores flow downstream. During 2005-12, discharge from the Pine Knot Mine Tunnel, the largest AMD source in the upper Schuylkill River Basin, had near-neutral pH and elevated concentrations of iron, manganese, and sulfate. Discharge from the tunnel responded rapidly to recharge but exhibited a prolonged recession compared to nearby streams, consistent with rapid infiltration and slow release of groundwater from the mine. Downstream of the AMD, dissolved iron was attenuated by oxidation and precipitation while dissolved CO2 degassed and pH increased. During high-flow conditions, the AMD and downstream waters exhibited decreased pH, iron, and sulfate with increased acidity that were modeled by mixing net-alkaline AMD with recharge or runoff having low ionic strength and low pH. Attenuation of dissolved iron within the river was least effective during high-flow conditions because of decreased transport time coupled with inhibitory effects of low pH on oxidation kinetics. A numerical model of groundwater flow was calibrated using groundwater levels in the Pine Knot Mine and discharge data for the Pine Knot Mine Tunnel and the West Branch Schuylkill River during a snowmelt event in January 2012. Although the calibrated model indicated substantial recharge to the mine complex took place away from streams, simulation of rapid changes in mine pool level and tunnel discharge during a high flow event in May 2012 required a source of direct recharge to the Pine Knot Mine. Such recharge produced small changes in mine pool level and rapid changes in tunnel flow rate because of extensive unsaturated storage capacity and high transmissivity within the mine complex. Thus, elimination of stream leakage could have a small effect on the annual discharge from the tunnel, but a large effect on peak discharge and associated water quality in streams.

Effects of land use and sample location on nitrate-stream flow hysteresis descriptors during storm events

USGS Publications Warehouse

Feinson, Lawrence S.; Gibs, Jacob; Imbrigiotta, Thomas E.; Garrett, Jessica D.

2016-01-01

The U.S. Geological Survey's New Jersey and Iowa Water Science Centers deployed ultraviolet-visible spectrophotometric sensors at water-quality monitoring sites on the Passaic and Pompton Rivers at Two Bridges, New Jersey, on Toms River at Toms River, New Jersey, and on the North Raccoon River near Jefferson, Iowa to continuously measure in-stream nitrate plus nitrite as nitrogen (NO3 + NO2) concentrations in conjunction with continuous stream flow measurements. Statistical analysis of NO3 + NO2 vs. stream discharge during storm events found statistically significant links between land use types and sampling site with the normalized area and rotational direction of NO3 + NO2-stream discharge (N-Q) hysteresis patterns. Statistically significant relations were also found between the normalized area of a hysteresis pattern and several flow parameters as well as the normalized area adjusted for rotational direction and minimum NO3 + NO2 concentrations. The mean normalized hysteresis area for forested land use was smaller than that of urban and agricultural land uses. The hysteresis rotational direction of the agricultural land use was opposite of that of the urban and undeveloped land uses. An r2 of 0.81 for the relation between the minimum normalized NO3 + NO2 concentration during a storm vs. the normalized NO3 + NO2 concentration at peak flow suggested that dilution was the dominant process controlling NO3 + NO2 concentrations over the course of most storm events.

Temporal trends and stationarity in annual peak flow and peak-flow timing for selected long-term streamflow-gaging stations in or near Montana through water year 2011: Chapter B in Montana StreamStats

USGS Publications Warehouse

Sando, Steven K.; McCarthy, Peter M.; Sando, Roy; Dutton, DeAnn M.

2016-04-05

The two low-elevation gaging stations in eastern Montana (Poplar River at international boundary [gaging station 06178000] and Powder River at Moorhead, Montana [gaging station 06324500]) had considerable changes in annual-peakflow characteristics after the mid-1970s, which might provide evidence of potential nonstationarity in the peak-flow records. The two low-elevation gaging stations that have potential nonstationarity are located in drainage basins that are strongly affected by agricultural activities that potentially affect the hydrologic regimes. Primary agricultural activities that might alter natural hydrologic conditions include construction of small impoundments (primarily for stock-watering purposes) and irrigation diversions. Temporal variability in these activities might contribute to the potential nonstationarity issues. Changes in climatic characteristics after the mid-1970s also possibly contribute to the potential nonstationarity issues. Lack of considerable indication of potential nonstationarity in annual peak flow for the other long-term gaging stations in this study might indicate that climatic changes have been more pronounced with respect to effects on peak flows in low elevation areas in eastern Montana than in areas represented by the other long-term gaging stations. Another possibility is that climatic changes after the mid-1970s are exacerbated in low-elevation areas where small-impoundment development and potential effects of irrigation diversions might be more extensive.

Spatial distribution of the largest rainfall-runoff floods from basins between 2.6 and 26,000 km2 in the United States and Puerto Rico

NASA Astrophysics Data System (ADS)

O'Connor, Jim E.; Costa, John E.

2004-01-01

We assess the spatial distribution of the largest rainfall-generated streamflows from a database of 35,663 flow records composed of the largest 10% of annual peak flows from each of 14,815 U.S. Geological Survey stream gaging stations in the United States and Puerto Rico. High unit discharges (peak discharge per unit contributing area) from basins with areas of 2.6 to 26,000 km2 (1-10,000 mi2) are widespread, but streams in Hawaii, Puerto Rico, and Texas together account for more than 50% of the highest unit discharges. The Appalachians and western flanks of Pacific coastal mountain systems are also regions of high unit discharges, as are several areas in the southern Midwest. By contrast, few exceptional discharges have been recorded in the interior West, northern Midwest, and Atlantic Coastal Plain. Most areas of high unit discharges result from the combination of (1) regional atmospheric conditions that produce large precipitation volumes and (2) steep topography, which enhances precipitation by convective and orographic processes and allows flow to be quickly concentrated into stream channels. Within the conterminous United States, the greatest concentration of exceptional unit discharges is at the Balcones Escarpment of central Texas, where maximum U.S. rainfall amounts apparently coincide with appropriate basin physiography to produce many of the largest measured U.S. floods. Flood-related fatalities broadly correspond to the spatial distribution of high unit discharges, with Texas having nearly twice the average annual flood-related fatalities of any other state.

Historical changes in annual peak flows in Maine and implications for flood-frequency analyses

USGS Publications Warehouse

Hodgkins, Glenn A.

2010-01-01

Flood-frequency analyses use statistical methods to compute peak streamflows for selected recurrence intervals— the average number of years between peak flows that are equal to or greater than a specified peak flow. Analyses are based on annual peak flows at a stream. It has long been assumed that the annual peak streamflows used in these computations were stationary (non-changing) over very long periods of time, except in river basins subject to direct effects of human activities, such as urbanization and regulation. Because of the potential effects of global warming on peak flows, the assumption of peak-flow stationarity has recently been questioned. Maine has many streamgages with 50 to 105 years of recorded annual peak streamflows. In this study, this long-term record has been tested for historical flood-frequency stationarity, to provide some insight into future flood frequency. Changes over time in annual instantaneous peak streamflows at 28 U.S. Geological Survey streamgages with long-term data (50 or more years) and relatively complete records were investigated by examining linear trends for each streamgage’s period of record. None of the 28 streamgages had more than 5 years of missing data. Eight streamgages have substantial streamflow regulation. Because previous studies have suggested that changes over time may have occurred as a step change around 1970, step changes between each streamgage’s older record (start year to 1970) and newer record (1971 to 2006) also were computed. The median change over time for all 28 streamgages is an increase of 15.9 percent based on a linear change and an increase of 12.4 percent based on a step change. The median change for the 20 unregulated streamgages is slightly higher than for all 28 streamgages; it is 18.4 percent based on a linear change and 15.0 percent based on a step change. Peak flows with 100- and 5-year recurrence intervals were computed for the 28 streamgages using the full annual peak-flow record and multiple sub-periods of that record using the guidelines (Bulletin 17B) of the Interagency Advisory Committee on Water Data. Magnitudes of 100- and 5-year peak flows computed from sub-periods then were compared to those computed from the full period. Sub-periods of 30 years with starting years staggered by 10 years were evaluated (1907–36, 1917–46, 1927–56, 1937–66, 1947–76, 1957–86, 1967–96, and 1977–2006). Two other sub-periods were evaluated using older data (start-of-record to 1970) and newer data (1971 to 2006). The 5-year peak flow is used to represent small and relatively frequent flood flows in Maine, whereas the 100-year peak flow is used to represent large flood flows. The 1967–96 sub-period generated the highest 100- and 5-year peak flows overall when compared to peak flows based on the full period of record; the median difference for all 28 streamgages is 8 percent for 100- and 5-year peak flows. The 1977–2006 and 1971–2006 sub-periods also generated 100- and 5-year peak flows higher than peak flows based on the full period of record, but not as high as the peak flows based on the 1967–96 sub-period. The 1937–66 sub-period generated the lowest 100- and 5-year peak flows overall. The median difference from full-period peak flows is -11 percent for 100-year peak flows and -8 percent for 5-year peak flows. Overall, differences between peak flows based on the sub-periods and those based on the full periods, generated using the 20 unregulated streamgages, are similar to differences using all 28 streamgages. Increases in the 5- and 100-year peak flows based on recent years of record are, in general, modest when compared to peak flows based on complete periods of record. The highest peak flows are based on the 1967–96 sub-period rather than the most recent sub-period (1977-2006). Peak flows for selected recurrence intervals are sensitive to very high peak flows that may occur once in a century or even less frequently. It is difficult, therefore, to determine which approach will produce the most reliable future estimates of peak flows for selected recurrence intervals, using only recent years of record or the traditional method using the entire historical period. One possible conservative approach to computing peak flows of selected recurrence intervals would be to compute peak flows using recent annual peak flows and the entire period of record, then choose the higher computed value. Whether recent or entire periods of record are used to compute peak flows of selected recurrence intervals, the results of this study highlight the importance of using recent data in the computation of the peak flows. The use of older records alone could result in underestimation of peak flows, particularly peak flows with short recurrence intervals, such as the 5-year peak flows.

Geomorphic and hydrologic study of peak-flow management on the Cedar River, Washington

USGS Publications Warehouse

Magirl, Christopher S.; Gendaszek, Andrew S.; Czuba, Christiana R.; Konrad, Christopher P.; Marineau, Mathieu D.

2012-01-01

Assessing the linkages between high-flow events, geomorphic response, and effects on stream ecology is critical to river management. High flows on the gravel-bedded Cedar River in Washington are important to the geomorphic function of the river; however, high flows can deleteriously affect salmon embryos incubating in streambed gravels. A geomorphic analysis of the Cedar River showed evidence of historical changes in river form over time and quantified the effects of anthropogenic alterations to the river corridor. Field measurements with accelerometer scour monitors buried in the streambed provided insight into the depth and timing of streambed scour during high-flow events. Combined with a two-dimensional hydrodynamic model, the recorded accelerometer disturbances allowed the prediction of streambed disturbance at the burial depth of Chinook and sockeye salmon egg pockets for different peak discharges. Insight gained from these analyses led to the development of suggested monitoring metrics for an ongoing geomorphic monitoring program on the Cedar River.

Lessons from accretion disks in cataclysmic variables

NASA Astrophysics Data System (ADS)

Horne, Keith

1998-04-01

We survey recent progress in the interpretation of observations of cataclysmic variables, whose accretion disks are heated by viscous dissipation rather than irradiation. Many features of standard viscous accretion disk models are confirmed by tomographic imaging studies of dwarf novae. Eclipse maps indicate that steady disk temperature structures are established during outbursts. Doppler maps of double-peaked emission lines suggest disk chromospheres heated by magnetic activity. Gas streams impacting on the disk rim leave expected signatures both in the eclipses and emission lines. Doppler maps of dwarf nova IP Peg at the beginning of an outburst show evidence for tidally-induced spiral shocks. While enjoying these successes, we must still face up to the dreaded ``SW Sex syndrome'' which afflicts most if not all cataclysmic variables in high accretion states. The anomalies include single-peaked emission lines with skewed kinematics, flat temperature-radius profiles, shallow offset line eclipses, and narrow low-ionization absorption lines at phase 0.5. The enigmatic behavior of AE Aqr is now largely understood in terms of a magnetic propeller model in which the rapidly spinning white dwarf magnetosphere expels the gas stream out of the system before an accretion disk can form. A final piece in this puzzle is the realization that an internal shock zone occurs in the exit stream at just the right place to explain the anomalous kinematics and violent flaring of the single-peaked emission lines. Encouraged by this success, we propose that disk-anchored magnetic propellers operate in the high accretion rate systems afflicted by the SW Sex syndrome. Magnetic fields anchored in the Keplerian disk sweep forward and apply a boost that expels gas stream material flowing above the disk plane. This working hypothesis offers a framework on which we can hang all the SW Sex anomalies. The lesson for theorists is that magnetic links appear to be transporting energy and angular momentum from the inner disk to distant parts of the flow without associated viscous heating in the disk.

Hydrogeomorphology of the hyporheic zone: stream solute and fine particle interactions with a dynamic streambed

USGS Publications Warehouse

Harvey, J.W.; Drummond, J.D.; Martin, R.L.; McPhillips, L.E.; Packman, A.I.; Jerolmack, D.J.; Stonedahl, S.H.; Aubeneau, A.F.; Sawyer, A.H.; Larsen, L.G.; Tobias, C.R.

2012-01-01

Hyporheic flow in streams has typically been studied separately from geomorphic processes. We investigated interactions between bed mobility and dynamic hyporheic storage of solutes and fine particles in a sand-bed stream before, during, and after a flood. A conservatively transported solute tracer (bromide) and a fine particles tracer (5 μm latex particles), a surrogate for fine particulate organic matter, were co-injected during base flow. The tracers were differentially stored, with fine particles penetrating more shallowly in hyporheic flow and retained more efficiently due to the high rate of particle filtration in bed sediment compared to solute. Tracer injections lasted 3.5 h after which we released a small flood from an upstream dam one hour later. Due to shallower storage in the bed, fine particles were rapidly entrained during the rising limb of the flood hydrograph. Rather than being flushed by the flood, we observed that solutes were stored longer due to expansion of hyporheic flow paths beneath the temporarily enlarged bedforms. Three important timescales determined the fate of solutes and fine particles: (1) flood duration, (2) relaxation time of flood-enlarged bedforms back to base flow dimensions, and (3) resulting adjustments and lag times of hyporheic flow. Recurrent transitions between these timescales explain why we observed a peak accumulation of natural particulate organic matter between 2 and 4 cm deep in the bed, i.e., below the scour layer of mobile bedforms but above the maximum depth of particle filtration in hyporheic flow paths. Thus, physical interactions between bed mobility and hyporheic transport influence how organic matter is stored in the bed and how long it is retained, which affects decomposition rate and metabolism of this southeastern Coastal Plain stream. In summary we found that dynamic interactions between hyporheic flow, bed mobility, and flow variation had strong but differential influences on base flow retention and flood mobilization of solutes and fine particulates. These hydrogeomorphic relationships have implications for microbial respiration of organic matter, carbon and nutrient cycling, and fate of contaminants in streams.

Geomorphic characteristics and classification of Duluth-area streams, Minnesota

USGS Publications Warehouse

Fitzpatrick, Faith A.; Peppler, Marie C.; DePhilip, Michele M.; Lee, Kathy E.

2006-01-01

In 2003 and 2004, a geomorphic assessment of streams in 20 watersheds in the Duluth, Minn., area was conducted to identify and summarize geomorphic characteristics, processes, disturbance mechanisms, and potential responses to disturbance. Methods used to assess the streams included watershed characterization, descriptions of segment slopes and valley types, historical aerial photograph interpretation, and rapid field assessments and intensive field surveys of stream reaches. Geomorphic conditions were summarized into a segment-scale classification with 15 categories mainly based on drainage-network position and slope, and, secondarily, based on geologic setting, valley type, and dominant geomorphic processes. Main causes of geomorphic disturbance included historical logging and agriculture, and ongoing urban development, human-caused channel alterations, road and storm sewer drainage, ditching, hiking trails, and gravel pits or quarries. Geomorphic responses to these disturbances are dependent on a combination of drainage-network position, slope, and geologic setting. Geologic setting is related to drainage-network position because the geologic deposits parallel the Lake Superior shoreline. Headwater streams in large watersheds flow over glacial deposits above altitudes of about 1,200 feet (ft). Headwater tributaries and upper main stems have ditch-like channels with gentle slopes and no valleys. Urban development and road drainage cause increased runoff and flood peaks in these segments resulting in channel widening. Below about 1,200 ft, main-stem segments generally are affected by bedrock type and structure and have steep slopes and confined or entrenched valleys. Increases in flood peaks do not cause incision or widening in the bedrock-controlled valleys; instead, the flow and scour areas are expanded. Feeder tributaries to these main stems have steep, confined valleys and may be sources for sediment from urban areas, road runoff, or storm sewer outfalls. Main-stem segments near the glacial deposits/surficial bedrock contact (1,000–1,200 ft) have the most potential for response to disturbance because they tend to have narrow valleys with sandy glacial lakeshore deposits and moderate slopes. Increases in flood peaks (from upstream increases in runoff) increase the potential for landslides and mass wasting from valley sides as well as channel widening.

Magnitude and frequency of floods in small drainage basins in Idaho

USGS Publications Warehouse

Thomas, C.A.; Harenberg, W.A.; Anderson, J.M.

1973-01-01

A method is presented in this report for determining magnitude and frequency of floods on streams with drainage areas between 0.5 and 200 square miles. The method relates basin characteristics, including drainage area, percentage of forest cover, percentage of water area, latitude, and longitude, with peak flow characteristics. Regression equations for each of eight regions are presented for determination of QIQ/ the peak discharge, which, on the average, will be exceeded once in 10 years. Peak flows, Q25 and Q 50 , can then be estimated from Q25/Q10 and Q-50/Q-10 ratios developed for each region. Nomographs are included which solve the equations for basins between 1 and 50 square miles. The regional regression equations were developed using multiple regression techniques. Annual peaks for 303 sites were analyzed in the study. These included all records on unregulated streams with drainage areas less than about 500 square miles with 10 years or more of record or which could readily be extended to 10 years on the basis of nearby streams. The log-Pearson Type III method as modified and a digital computer were employed to estimate magnitude and frequency of floods for each of the 303 gaged sites. A large number of physical and climatic basin characteristics were determined for each of the gaged sites. The multiple regression method was then applied to determine the equations relating the floodflows and the most significant basin characteristics. For convenience of the users, several equations were simplified and some complex characteristics were deleted at the sacrifice of some increase in the standard error. Standard errors of estimate and many other statistical data were computed in the analysis process and are available in the Boise district office files. The analysis showed that QIQ was the best defined and most practical index flood for determination of the Q25 and 0,50 flood estimates.Regression equations are not developed because of poor definition for areas which total about 20,000 square miles, most of which are in southern Idaho. These areas are described in the report to prevent use of regression equations where they do not apply. They include urbanized areas, streams affected by regulation or diversion by works of man, unforested areas, streams with gaining or losing reaches, streams draining alluvial valleys and the Snake Plain, intense thunderstorm areas, and scattered areas where records indicate recurring floods which depart from the regional equations. Maximum flows of record and basin locations are summarized in tables and maps. The analysis indicates deficiencies in data exist. To improve knowledge regarding flood characteristics in poorly defined areas, the following data-collection programs are recommended. Gages should be operated on a few selected small streams for an extended period to define floods at long recurrence intervals. Crest-stage gages should be operated in representative basins in urbanized areas, newly developed irrigated areas and grasslands, and in unforested areas. Unusual floods should continue to be measured at miscellaneous sites on regulated streams and in intense thunderstorm-prone areas. The relationship between channel geometry and floodflow characteristics should be investigated as an alternative or supplement to operation of gaging stations. Documentation of historic flood data from newspapers and other sources would improve the basic flood-data base.

Quantifying Hydrological Ecosystem Services of Various Land Covers and Uses on Small Experimental Catchments within the Panama Canal Watershed: The Agua Salud Project

NASA Astrophysics Data System (ADS)

Crouch, T. D.; Ogden, F. L.; Agua Salud Project

2011-12-01

As a part of the Agua Salud Project, a baseline characterization of hydrologic processes on the small catchment scale (~0.24 to 2.0 km2) is assessed across different land uses and covers typical to rural Panama. The land covers being monitored include a mature secondary forest, a disturbed catchment with a mosaic of various aged secondary growth and agricultural use, an active pasture and a monoculture invasive grass site as experimental controls, and two treated catchments that were recently abandoned pastures converted to teak and native species timber plantations. The catchments are found within Panama's protected Soberania National Park and the adjacent headwaters of the Agua Salud and Mendoza Rivers, all part of the greater Panama Canal Watershed. Using hydrological data from the first two and a half years of the project, three main ecosystem services are observed. The forested area exhibited lower storm event peaks, decreased flashiness, and greater stream flow during the dry season compared to the disturbed mosaic site. Lower hydrograph peaks and flashiness mitigate the risk of substantial flood damage during the major flood events generally seen in Panama between October and December. The mature forest (1.35 km2) catchment has shown lower average flood peaks in comparison to the disturbed site. For storm peaks less than 6 mm/hr, flood peaks are on average 51% lower. For storm peaks greater than 6 mm/hr, flood peaks are approximately 40% lower. In 1998, draft restrictions were imposed in the Panama Canal because of a deficit of dry season water after an El Niño-Southern Oscillation resulted in decreased wet season rainfall. The water that is available during the end of the dry season has the potential to insure the full operation of the Canal during El Niño drought years. Toward the end of the dry season (March through May) our data shows that roughly 34% more water was available during a relatively dry year with respect to antecedent wet season rainfall, 13% more water was available during a normal or moderate water year, and 0.13% more water after a record-breaking wet season. During the 2009 and 2010 wet seasons, the forested catchment exhibited 53% and 48% less stream flow than the disturbed mosaic catchment, respectively. Following the 2009 and 2010 wet seasons, the catchment exhibited 10% more stream flow over the entire 2010 dry season and 22% less over the entire 2011 dry season, respectively. What causes this difference across seasons, and how can we explain the "sponged" excess water released toward the end of the dry season by the forested catchment? Water balance closure and flow-path are explored to address these questions and understand seasonal variations in evapotranspiration and groundwater storage dynamics.

Episodic acidification of a coastal plain stream in Virginia

USGS Publications Warehouse

O'Brien, A. K.; Eshleman, K.N.

1996-01-01

This study investigates the episodic acidification of Reedy Creek, a wetland-influenced coastal plain stream near Richmond, Virginia. Primary objectives of the study were to quantify the episodic variability of acid- base chemistry in Reedy Creek, to examine the seasonal variability in episodic response and to explain the hydrological and geochemical factors that contribute to episodic acidification. Chemical response was similar in each of the seven storms examined, however, the ranges in concentrations observed were commonly greater in summer/fall storms than in winter/spring storms. An increase in SO4/2- concentration with discharge was observed during all storms and peak concentration occurred at or near peak flow. Small increases in Mg2+, Ca2+, K+ concentrations and dissolved organic carbon (DOC) were observed during most storms. At the same time, ANC, Na+ and Cl- concentrations usually decreased with increasing discharge. In summer/fall storms, the absolute increase in SO4/2- concentration was one-third to 15 times the increase observed in winter/spring storms; the decrease in ANC during summer/fall storms was usually within the range of the decrease observed in winter/spring storms. In contrast, the decrease in Na+ and Cl- concentrations during winter/spring storms was much greater than that observed during summer/fall storms. Data show that while base flow anion deficit was higher in summer/fall than in winter/spring, anion deficit decreased during most summer/fall storms. In contrast, base flow anion deficit was lower in spring and winter, but increased during winter/spring storms. Increased SO4/2- concentration was the main cause of episodic acidification during storms at Reedy Creek, but increased anion deficit indicates organic acids may contribute to episodic acidification during winter/spring storms. Changes in SO4/2- concentration coincident with the hydrograph rise indicate quick routing of water through the watershed. Saturation overland flow appears to be the likely mechanism by which solutes are transported to the stream during storm flow.

Relating a Jet-Surface Interaction Experiment to a Commercial Supersonic Transport Aircraft Using Numerical Simulations

NASA Technical Reports Server (NTRS)

Dippold, Vance F. III; Friedlander, David

2017-01-01

Reynolds-Averaged Navier-Stokes (RANS) simulations were performed for a commercial supersonic transport aircraft concept and experimental hardware models designed to represent the installed propulsion system of the conceptual aircraft in an upcoming test campaign. The purpose of the experiment is to determine the effects of jet-surface interactions from supersonic aircraft on airport community noise. RANS simulations of the commercial supersonic transport aircraft concept were performed to relate the representative experimental hardware to the actual aircraft. RANS screening simulations were performed on the proposed test hardware to verify that it would be free from potential rig noise and to predict the aerodynamic forces on the model hardware to assist with structural design. The simulations showed a large region of separated flow formed in a junction region of one of the experimental configurations. This was dissimilar with simulations of the aircraft and could invalidate the noise measurements. This configuration was modified and a subsequent RANS simulation showed that the size of the flow separation was greatly reduced. The aerodynamic forces found on the experimental models were found to be relatively small when compared to the expected loads from the model’s own weight.Reynolds-Averaged Navier-Stokes (RANS) simulations were completed for two configurations of a three-stream inverted velocity profile (IVP) nozzle and a baseline single-stream round nozzle (mixed-flow equivalent conditions). For the Sideline and Cutback flow conditions, while the IVP nozzles did not reduce the peak turbulent kinetic energy on the lower side of the jet plume, the IVP nozzles did significantly reduce the size of the region of peak turbulent kinetic energy when compared to the jet plume of the baseline nozzle cases. The IVP nozzle at Sideline conditions did suffer a region of separated flow from the inner stream nozzle splitter that did produce an intense, but small, region of turbulent kinetic energy in the vicinity of the nozzle exit. When viewed with the understanding that jet noise is directly related to turbulent kinetic energy, these IVP nozzle simulations show the potential to reduce noise to observers located below the nozzle. However, these RANS simulations also show that some modifications may be needed to prevent the small region of separated flow-induced turbulent kinetic energy from the inner stream nozzle splitter at Sideline conditions.

Steep Gravel Bedload Rating Curves Obtained From Bedload Traps Shift Effective Discharge to Flows Much Higher Than "Bankfull"

NASA Astrophysics Data System (ADS)

Bunte, K.; Swingle, K. W.; Abt, S. R.; Cenderelli, D.

2012-12-01

Effective discharge (Qeff) is defined as the flow at which the product of flow frequency and bedload transport rates obtains its maximum. Qeff is often reported to correspond with bankfull flow (Qbf), where Qeff approximates the 1.5 year recurrence interval flow (Q1.5). Because it transports the majority of all bedload, Qeff is considered a design flow for stream restoration and flow management. This study investigates the relationship between Qeff and Q1.5 for gravel bedload in high elevation Rocky Mountain streams. Both the flow frequency distribution (FQ = a × Qbin-b) where Qbin is the flow class, and the bedload transport rating curve (QB = c × Qd) can be described by power functions. The product FQ × QB = (a × c × Q(-b + d)) is positive if d + -b >0, and negative if d + -b <0. FQ × QB can only attain a maximum (=Qeff) if either FQ or QB exhibit an inflection point. In snowmelt regimes, low flows prevail for much of the year, while high flows are limited to a few days, and extreme floods are rare. In log-log plotting scale, this distribution causes the longterm flow frequency function FQ to steepen in the vicinity of Q1.5. If the bedload rating curve exponent is small, e.g., = 3 as is typical of Helley-Smith bedload samples, d + -b shifts from >0 to <0, causing FQ × QB to peak, and Qeff to be around Q1.5. For measurements thought to be more representative of actual gravel transport obtained using bedload traps and similar devices, large rating curve exponents d of 6 - 16 are typical. In this case, d + -b remains >0, and FQ × QB reaches its maximum near the largest flow on record (Qeff,BT = Qmax). Expression of FQ by negative exponential functions FQ = k × e(Qbin×-m) smooths the product function FQ × QB that displays its maximum as a gentle hump rather than a sharp peak, but without drastically altering Qeff. However, a smooth function FQ × QB allows Qeff to react to small changes in rating curve exponents d. As d increases from <1 to >10, Qeff increases from Qmin to Qmax. The S-shaped relationship of Qeff vs. d shows that changes in d between about 4 and 8 exert the largest influence on Qeff. Not only FQ, but also QB may change its steepness. QB may flatten during floods as flows overtop banks. Many high elevation Rocky Mountain streams are entrenched due to floodplain buildup (overbank deposition and beaver activity) and downcutting. Preliminary flow modeling suggests that bank overtopping starts when Q1.5 >150%, and flows are fully out-of-bank past 200-250% Q1.5. A flattening of the bedload rating curve shifts Qeff from Qmax to within 150-250% Q1.5. Study results suggest that Qeff likely occurs within 150-250% Q1.5, and the often-quoted similarity of Qeff and Qbf (assuming Qbf = Q1.5) does not hold for the study streams, but is rather an artifact of using a Helley-Smith sampler that produces low rating curve exponents near 3. This finding calls into question the utility of Q1.5 or "bankfull flow" as a morphological design flow in high elevation Rocky Mountain streams.

Modeling E. coli Release And Transport In A Creek During Artificial High-Flow Events

NASA Astrophysics Data System (ADS)

Yakirevich, A.; Pachepsky, Y. A.; Gish, T. J.; Cho, K.; Shelton, D. R.; Kuznetsov, M. Y.

2012-12-01

In-stream fate and transport of E. coli, is a leading indicator of microbial contamination of natural waters, and so needs to be understood to eventually minimize surface water contamination by microbial organisms. The objective of this work was to simulate E. coli release and transport from soil sediment in a creek bed both during and after high water flow events. The artificial high-water flow events were created by releasing 60-80 m3 of city water on a tarp-covered stream bank at a rate of 60 L/s in four equal allotments in July of 2008, 2009 and 2010. The small first-order creek used in this study is part of the Beaver Dam Creek Tributary and is located at the USDA Optimizing Production inputs for Economic and Environmental Enhancement (OPE3) research site, in Beltsville, Maryland. In 2009 and 2010 a conservative tracer difluorobenzoic acid (DFBA) was added to the released water. Specifically, water flow rates, E. coli and DFBA concentrations as well as water turbidity were monitored with automated samplers at the ends of the three in-stream weirs reaching a total length of 630 m. Sediment particle size distributions and the streambed E. coli concentrations were measured along a creek before and after experiment. The observed DFBA breakthrough curves (BTCs) exhibited long tails after the water pulse and tracer peaks indicating that transient storage might be an important element of the in-stream transport process. Turbidity and E. coli BTCs also exhibited long tails indicative of transient storage and low rates of settling caused by re-entrainment. Typically, turbidity peaked prior to E. coli and returned to lower base-line levels more rapidly. A one-dimensional model was applied to simulate water flow, E. coli and DFBA transport during these experiments. The Saint-Venant equations were used to calculate water depth and discharge while a stream solute transport model accounted for advection-dispersion, lateral inflow/outflow, exchange with the transient storage, and resuspension of bacteria by shear stress from stream bottom sediments. Reach-specific model parameters were estimated by using observed time series of flow rates and concentrations at three weir stations. Transient storage and dispersion parameters were obtained with DFBA BTCs, then critical shear stress and resuspension rate were assessed by fitting computed E. coli BTCs to observations. To obtain a good model fit for E. coli, we generally had to make the transient storage for E. coli larger than for DFBA. Comparison of simulated and measured E. coli concentrations indicated that significant resuspension of E. coli continued when water flow returned to the base level after the water pulse passed and bottom shear stress was small. The hypothetical mechanism of this extended release could be the enhanced boundary layer (water-streambed) exchange due to changes in biofilm properties by erosion and sloughing detachment.

Effects of a beaver pond on runoff processes: comparison of two headwater catchments

USGS Publications Warehouse

Burns, Douglas A.; McDonnell, Jeffery J.

1998-01-01

Natural variations in concentrations of 18O, D, and H4SiO4 in two tributary catchments of Woods Lake in the west-central Adirondack Mountains of New York were measured during 1989–1991 to examine runoff processes and their implications for the neutralization of acidic precipitation by calcium carbonate treatment. The two catchments are similar except that one contained a 1.3 ha beaver pond. Evaporation from the beaver pond caused a seasonal decrease in the slope of the meteoric water line in stream water from the catchment with a beaver pond (WO2). No corresponding change in slope of the meteoric water line was evident in stream water from the other catchment (WO4), nor in ground water nor soil water from either catchment, indicating that evaporative fractionation was not significant. Application of a best-fit sine curve to δ18O data indicated that base flow in both catchments had a residence time of about 100 days. Ground water from a well finished in thick till had the longest residence time (160 days); soil water from the O-horizon and B-horizon had residence times of 63 and 80 days, respectively. Water previously stored within each catchment (pre-event water) was the predominant component of streamflow during spring snowmelt and during spring and autumn rainfall events, but the proportion of streamflow that consisted of pre-event water differed significantly in the two catchments. The proportion of event water (rain and snowmelt) in WO2 was smaller than at WO4 early in the spring snowmelt of March 13–17, 1990, but the proportions of source water components for the two catchments were almost indistinguishable by the peak flow on the third day of the melt. The event water was further separated into surface-water and subsurface-water components by utilizing measured changes in H4SiO4 concentrations in stream water during the snowmelt. Results indicated that subsurface flow was the dominant pathway by which event water reached the stream except during the peak flow of a rain-on-snow event on the last day of the melt. Streamflow from a spring rain storm with dry antecendent conditions two months later (May 16–18, 1990), was less than 5% event water at peak flow in WO2 and 26% in WO4. This change from the runoff pattern in March is attributed to retention of event water in the beaver pond favored by relatively low pre-event storage and isothermal (nonstratified) conditions in the pond that allowed mixing. Streamflow during several autumn storms was about 15–25% event water at peak flow in WO4; the highest values for event water were associated with wet antecedent moisture conditions. These results indicate that a beaver pond can significantly affect the downstream delivery of event water through evaporation and mixing, but provides minimal retention during large runoff events such as snowmelt. Beaver ponds are expected to provide greater opportunity for neutralization of acidic waters during most of the year in catchments treated with calcium carbonate, but little neutralization effect during snowmelt.

Metal-coated microfluidic channels: An approach to eliminate streaming potential effects in nano biosensors.

PubMed

Lee, Jieun; Wipf, Mathias; Mu, Luye; Adams, Chris; Hannant, Jennifer; Reed, Mark A

2017-01-15

We report a method to suppress streaming potential using an Ag-coated microfluidic channel on a p-type silicon nanowire (SiNW) array measured by a multiplexed electrical readout. The metal layer sets a constant electrical potential along the microfluidic channel for a given reference electrode voltage regardless of the flow velocity. Without the Ag layer, the magnitude and sign of the surface potential change on the SiNW depends on the flow velocity, width of the microfluidic channel and the device's location inside the microfluidic channel with respect to the reference electrode. Noise analysis of the SiNW array with and without the Ag coating in the fluidic channel shows that noise frequency peaks, resulting from the operation of a piezoelectric micropump, are eliminated using the Ag layer with two reference electrodes located at inlet and outlet. This strategy presents a simple platform to eliminate the streaming potential and can become a powerful tool for nanoscale potentiometric biosensors. Copyright © 2016 Elsevier B.V. All rights reserved.

Attributes of Yellowstone cutthroat trout redds in a tributary of the Snake River, Idaho

Treesearch

Russell F. Thurow; John G. King

1994-01-01

We characterized spawning sites of Yellowstone cutthroat trout Oncorhynchus clarki bouvieri, described the microhabitat of completed redds, and tested the influence of habitat conditions on the morphology of completed redds in Pine Creek, Idaho. Cutthroat trout spawned in June as flows subsided after peak stream discharge. During spawning, minimum and maximum water...

Application of a sediment-transport model to estimate bridge scour at selected sites in Colorado, 1991-93

USGS Publications Warehouse

Vaill, J.E.

1995-01-01

A bridge-scour study by the U.S. Geological Survey, in cooperation with the Colorado Department of Transportation, was begun in 1991 to evaluate bridges in the State for potential scour during floods. A part of that study was to apply a computer model for sediment-transport routing to simulate channel aggradation or degradation and pier scour during floods at three bridge sites in Colorado. Stream-channel reaches upstream and downstream from the bridges were simulated using the Bridge Stream Tube model for Alluvial River Simulation (BRI-STARS). Synthetic flood hydrographs for the 500-year floods were developed for Surveyor Creek near Platner and for the Rio Grande at Wagon Wheel Gap. A part of the recorded mean daily hydrograph for the peak flow of record was used for the Yampa River near Maybell. The recorded hydrograph for the peak flow of record exceeded the computed 500-year-flood magnitude for this stream by about 22 percent. Bed-material particle-size distributions were determined from samples collected at Surveyor Creek and the Rio Grande. Existing data were used for the Yampa River. The model was used to compute a sediment-inflow hydrograph using particle-size data collected and a specified sediment-transport equation at each site. Particle sizes ranged from less than 0.5 to 16 millimeters for Surveyor Creek, less than 4 to 128 millimeters for the Yampa River, and 22.5 to 150 millimeters for the Rio Grande. Computed scour at the peak steamflows ranged from -2.32 feet at Surveyor Creek near Platner to +0.63 foot at the Rio Grande at Wagon Wheel Gap. Pier- scour depths computed at the peak streamflows ranged from 4.46 feet at the Rio Grande at Wagon Wheel Gap to 5.94 feet at the Yampa River near Maybell. The number of streamtubes used in the model varied at each site.

Flood of January 1982 in the San Francisco Bay area, California

USGS Publications Warehouse

Blodgett, J.C.; Chin, E.H.

1989-01-01

A major winter storm originating over the Pacific Ocean moved through central California in early January 1982. As much as 16 inches of rain fell in Marin County and 25 inches in the mountains bordering Santa Cruz County. The storm of January 3-5, 1982 had a stable atmospheric structure, and the layer of moist maritime air was confined to altitudes between 50 and 700 ft; this phenomenon caused the rain to fall most heavily along the lower slopes of the coastal mountains. As a result of antecedent rainfall, streamflow in the San Francisco Bay area exceeded normal from the end of October to the end of December 1981. For most streams, the January 1982 flood was the largest since the flood of December 1955, but it was not significantly large in comparison with historic peak-flow data. Damages associated with the storm were substantial, but flooding from stream runoff was not the major problem. Greater than normal antecedent rainfall, together with the prolonged heavy rain, liquified the supersaturated soil cover and caused numerous slope failures and debris flows on steep, unstable slopes. The median recurrence interval of the 1982 peak for 66 streamflow-gaging stations in the San Francisco Bay area is 10 years; for the 1955 flood, the median recurrence interval for 16 stations is 11 years. Streams with highest unit peak runoff were in the Santa Cruz Mountains and North Bay subareas. Median recurrence intervals of flood volumes for durations of 1, 3, and 8 consecutive days during the January 1982 flood are 18, 11, and 8; these recurrence intervals are comparable to those of the December 1955 flood, which are 13 , 16, and 14 years. (USGS)

Simulated flow and solute transport, and mitigation of a hypothetical soluble-contaminant spill for the New River in the New River Gorge National River, West Virginia

USGS Publications Warehouse

Wiley, J.B.

1993-01-01

This report presents the results of a study by the U.S. Geological Survey (USGS), in cooperation with the National Park Service, to investigate the transport and factors affecting mitigation of a hypothetical spill of a soluble contaminant into the New River in the New River Gorge National River, West Virginia. The study reach, 53 miles of the lower New River between Hinton and Fayette, is characterized as a pool-and-riffle stream that becomes narrower, steeper, and deeper in the downstream direction. A USGS unsteady-flow model, DAFLOW (Diffusion Analogy FLOW), and a USGS solute-transport model, BLTM (Branch Lagrangian Transport Model), were applied to the study reach. Increases in discharge caused decreases in peak concentration and traveltime of peak concentration. Decreases in discharge caused increases in peak concentration and traveltime of peak concentration. This study indicated that the effects of an accidental spill could be mitigated by regulating discharge from Bluestone Dam. Knowledge of the chemical characteristics of the spill, location and time of the spill, and discharge of the river can aid in determining a mitigation response.

Impact of meander geometry and stream flow events on residence times and solute transport in the intra-meander flow

NASA Astrophysics Data System (ADS)

Nasir Mahmood, Muhammad; Schmidt, Christian; Trauth, Nico

2017-04-01

Stream morphological features, in combination with hydrological variability play a key role in water and solute exchange across surface and subsurface waters. Meanders are prominent morphological features within stream systems which exhibit unique hydrodynamics. The water surface elevation difference across the inner bank of a meander induces lateral hyporheic exchange within the intra-meander region. This hyporheic flow is characterized by considerably prolonged flow paths and residence times (RT) compared to smaller scales of hyporheic exchange. In this study we examine the impact of different meander geometries on the intra-meander hyporheic flow field and solute mobilization under both steady state and transient flow conditions. We developed a number of artificial meander shape scenarios, representing various meander evolution stages, ranging from a typical initial to advanced stage (near cut off ) meander. Three dimensional steady state numerical groundwater flow simulations including the unsaturated zone were performed for the intra-meander region. The meandering stream was implemented in the model by adjusting the top layers of the modelling domain to the streambed elevation and assigning linearly decreasing head boundary conditions to the streambed cells. Residence times for the intra-meander region were computed by advective particle tracking across the inner bank of meander. Selected steady state cases were extended to transient flow simulations to evaluate the impact of stream discharge events on the temporal behavior of the water exchange and solute transport in the intra-meander region. The transient stream discharge was simulated for a number of discharge events of variable duration and peak height using the surface water model HEC-RAS. Transient hydraulic heads obtained from the surface water model were applied as transient head boundary conditions to the streambed cells of the groundwater model. A solute concentration source was added in the unsaturated zone to evaluate the effect of transient flow conditions on solute mobilization. Our preliminary results indicate that residence times ranging from 0.5 to 250 hours are influenced by meander geometry, as well as the size of the intra-meander area. In general, we found that larger intra-meander areas lead to longer flow paths and higher mean intra-meander residence times (MRTs). The shortest RTs were observed near the meander neck in all scenarios, a feature most predominant in more developed meander resulting shorter MRTs. Transient modelling results show that fluctuations in stream hydraulic head influence the transport and zonation of the solute concentration in the intra-meander area with higher and longer stream discharge events leading to stronger mobilization and removal of solutes dominated mainly around meander neck area.

Water in the Balance: A Parking Lot Story

NASA Astrophysics Data System (ADS)

Haas, N. A.; Vitousek, S.

2017-12-01

The greater Chicagoland region has seen a high degree of urbanization since 1970. For example, between 1970-1990 the region experienced 4% population growth, a 35% increase in urban land use, and approximately 454 square miles of agricultural land was mostly converted into urban uses. Transformation of land into urban uses in the Chicagoland region has altered the stream and catchment response to rainfall events, specifically an increase in stream flashiness and increase in urban flooding. Chicago has begun to address these changes through green infrastructure. To understand the impact of green infrastructure at local, city-wide, and watershed scales, individual projects need to be accurately and sufficiently modeled. A traditional parking lot conversion into a porous parking lot at the University of Illinois at Chicago was modeled using SWMM and scrutinized using field data to look at stormwater runoff and water balance prior and post reconstruction. SWMM modeling suggested an 87% reduction in peak flow as well as a 100% reduction in flooding for a 24 hour, 1.72-inch storm. For the same storm, field data suggest an 89% reduction in peak flow as well as a 100% reduction in flooding. Modeling suggested 100% reductions in flooding for longer duration storms (24 hour+) and a smaller reduction in peak flow ( 66%). The highly parameterized SWMM model agrees well with collected data and analysis. Further effort is being made to use data mining to create correlations within the collected datasets that can be integrated into a model that follows a standardized formation process and reduces parameterization.

Methods for estimating magnitude and frequency of floods in Arizona, developed with unregulated and rural peak-flow data through water year 2010

USGS Publications Warehouse

Paretti, Nicholas V.; Kennedy, Jeffrey R.; Turney, Lovina A.; Veilleux, Andrea G.

2014-01-01

The regional regression equations were integrated into the U.S. Geological Survey’s StreamStats program. The StreamStats program is a national map-based web application that allows the public to easily access published flood frequency and basin characteristic statistics. The interactive web application allows a user to select a point within a watershed (gaged or ungaged) and retrieve flood-frequency estimates derived from the current regional regression equations and geographic information system data within the selected basin. StreamStats provides users with an efficient and accurate means for retrieving the most up to date flood frequency and basin characteristic data. StreamStats is intended to provide consistent statistics, minimize user error, and reduce the need for large datasets and costly geographic information system software.

Seasonal patterns in nutrients, carbon, and algal responses in wadeable streams within three geographically distinct areas of the United States, 2007-08

USGS Publications Warehouse

Lee, Kathy E.; Lorenz, David L.; Petersen, James C.; Greene, John B.

2012-01-01

The U.S. Geological Survey determined seasonal variability in nutrients, carbon, and algal biomass in 22 wadeable streams over a 1-year period during 2007 or 2008 within three geographically distinct areas in the United States. The three areas are the Upper Mississippi River Basin (UMIS) in Minnesota, the Ozark Plateaus (ORZK) in southern Missouri and northern Arkansas, and the Upper Snake River Basin (USNK) in southern Idaho. Seasonal patterns in some constituent concentrations and algal responses were distinct. Nitrate concentrations were greatest during the winter in all study areas potentially because of a reduction in denitrification rates and algal uptake during the winter, along with reduced surface runoff. Decreases in nitrate concentrations during the spring and summer at most stream sites coincided with increased streamflow during the snowmelt runoff or spring storms indicating dilution. The continued decrease in nitrate concentrations during summer potentially is because of a reduction in nitrate inputs (from decreased surface runoff) or increases in biological uptake. In contrast to nitrate concentrations, ammonia concentrations varied among study areas. Ammonia concentration trends were similar at UMIS and USNK sampling sites with winter peak concentrations and rapid decreases in ammonia concentrations by spring or early summer. In contrast, ammonia concentrations at OZRK sampling sites were more variable with peak concentrations later in the year. Ammonia may accumulate in stream water in the winter under ice and snow cover at the UMIS and USNK sites because of limited algal metabolism and increased mineralization of decaying organic matter under reducing conditions within stream bottom sediments. Phosphorus concentration patterns and the type of phosphorus present changes with changing hydrologic conditions and seasons and varied among study areas. Orthophosphate concentrations tended to be greater in the summer at UMIS sites, whereas total phosphorus concentrations at most UMIS and USNK sites peaked in the spring during runoff and then decreased through the remainder of the sampling period. Total phosphorus and orthophosphate concentrations in OZRK streams peaked during summer indicating a runoff-based source of both nutrients. Orthophosphate concentrations may increase in streams in the late summer when surface runoff composes less of total streamflow, and when groundwater containing orthophosphate becomes a more dominant source in streams during lower flows. Seston chlorophyll a concentrations were greatest early in the growing season (spring), whereas the spring runoff events coincided with reductions in benthic algal chlorophyll a biomass likely because of scour of benthic algae from the channel bottom that are entrained in the water column during that period. Nitrate, ammonia, and orthophosphate concentrations also decreased during that same period, indicating dilution in the spring during runoff events. The data from this study indicate that the source of water (surface runoff or groundwater) to a stream and the intensity of major runoff events are important factors controlling instream concentrations. Biological processes appear to affect nutrient concentrations during more stable lower flow periods in later summer, fall, and winter when residence time of water in a channel is longer, which allows more time for biological uptake and transformations. Management of nutrient conditions in streams is challenging and requires an understanding of multiple factors that affect in-stream nutrient concentrations and biological uptake and growth.

Magnitude and Frequency of Floods for Urban and Small Rural Streams in Georgia, 2008

USGS Publications Warehouse

Gotvald, Anthony J.; Knaak, Andrew E.

2011-01-01

A study was conducted that updated methods for estimating the magnitude and frequency of floods in ungaged urban basins in Georgia that are not substantially affected by regulation or tidal fluctuations. Annual peak-flow data for urban streams from September 2008 were analyzed for 50 streamgaging stations (streamgages) in Georgia and 6 streamgages on adjacent urban streams in Florida and South Carolina having 10 or more years of data. Flood-frequency estimates were computed for the 56 urban streamgages by fitting logarithms of annual peak flows for each streamgage to a Pearson Type III distribution. Additionally, basin characteristics for the streamgages were computed by using a geographical information system and computer algorithms. Regional regression analysis, using generalized least-squares regression, was used to develop a set of equations for estimating flows with 50-, 20-, 10-, 4-, 2-, 1-, 0.5-, and 0.2-percent annual exceedance probabilities for ungaged urban basins in Georgia. In addition to the 56 urban streamgages, 171 rural streamgages were included in the regression analysis to maintain continuity between flood estimates for urban and rural basins as the basin characteristics pertaining to urbanization approach zero. Because 21 of the rural streamgages have drainage areas less than 1 square mile, the set of equations developed for this study can also be used for estimating small ungaged rural streams in Georgia. Flood-frequency estimates and basin characteristics for 227 streamgages were combined to form the final database used in the regional regression analysis. Four hydrologic regions were developed for Georgia. The final equations are functions of drainage area and percentage of impervious area for three of the regions and drainage area, percentage of developed land, and mean basin slope for the fourth region. Average standard errors of prediction for these regression equations range from 20.0 to 74.5 percent.

Measurements and Predictions of the Noise from Three-Stream Jets

NASA Technical Reports Server (NTRS)

Henderson, Brenda S.; Leib, Stewart J.; Wernet, Mark P.

2015-01-01

An experimental and numerical investigation of the noise produced by high-subsonic and supersonic three-stream jets was conducted. The exhaust system consisted of externally-mixed-convergent nozzles and an external plug. Bypass- and tertiary-to-core area ratios between 1.0 and 2.5, and 0.4 and 1.0, respectively, were studied. Axisymmetric and offset tertiary nozzles were investigated for heated and unheated conditions. For axisymmetric configurations, the addition of the third stream was found to reduce peak- and high-frequency acoustic levels in the peak-jet-noise direction, with greater reductions at the lower bypass-to-core area ratios. For the offset configurations, an offset duct was found to decrease acoustic levels on the thick side of the tertiary nozzle relative to those produced by the simulated two-stream jet with up to 8 dB mid-frequency noise reduction at large angles to the jet inlet axis. Noise reduction in the peak-jet-noise direction was greater for supersonic core speeds than for subsonic core speeds. The addition of a tertiary nozzle insert used to divert the third-stream jet to one side of the nozzle system provided no noise reduction. Noise predictions are presented for selected cases using a method based on an acoustic analogy with mean flow interaction effects accounted for using a Green's function, computed in terms of its coupled azimuthal modes for the offset cases, and a source model previously used for round and rectangular jets. Comparisons of the prediction results with data show that the noise model predicts the observed increase in low-frequency noise with the introduction of a third, axisymmetric stream, but not the high-frequency reduction. For an offset third stream, the model predicts the observed trend of decreased sound levels on the thick side of the jet compared with the thin side, but the predicted azimuthal variations are much less than those seen in the data. Also, the shift of the spectral peak to lower frequencies with increasing polar angle is over-predicted. For an offset third stream with a heated core, it is shown that including the enthalpy-flux source terms in the acoustic analogy model improves predictions compared with those obtained using only the momentum flux.

Measurements and Predictions of the Noise from Three-Stream Jets

NASA Technical Reports Server (NTRS)

Henderson, Brenda S.; Leib, Stewart J.; Wernet, Mark P.

2015-01-01

An experimental and numerical investigation of the noise produced by high-subsonic and supersonic three-stream jets was conducted. The exhaust system consisted of externally-mixed-convergent nozzles and an external plug. Bypass- and tertiary- to-core area ratios between 1.0 and 2.5, and 0.4 and 1.0, respectively, were studied. Axisymmetric and offset tertiary nozzles were investigated for heated and unheated conditions. For axisymmetric configurations, the addition of the third stream was found to reduce peak- and high-frequency acoustic levels in the peak-jet-noise direction, with greater reductions at the lower bypass-to-core area ratios. For the offset configurations, an offset duct was found to decrease acoustic levels on the thick side of the tertiary nozzle relative to those produced by the simulated two-stream jet with up to 8 dB mid-frequency noise reduction at large angles to the jet inlet axis. Noise reduction in the peak-jet-noise direction was greater for supersonic core speeds than for subsonic core speeds. The addition of a tertiary nozzle insert used to divert the third-stream jet to one side of the nozzle system provided no noise reduction. Noise predictions are presented for selected cases using a method based on an acoustic analogy with mean flow interaction effects accounted for using a Green's function, computed in terms of its coupled azimuthal modes for the offset cases, and a source model previously used for round and rectangular jets. Comparisons of the prediction results with data show that the noise model predicts the observed increase in low-frequency noise with the introduction of a third, axisymmetric stream, but not the high-frequency reduction. For an offset third stream, the model predicts the observed trend of decreased sound levels on the thick side of the jet compared with the thin side, but the predicted azimuthal variations are much less than those seen in the data. Also, the shift of the spectral peak to lower frequencies with increasing polar angle is over-predicted. For an offset third stream with a heated core, it is shown that including the enthalpy-flux source terms in the acoustic analogy model improves predictions compared with those obtained using only the momentum- flux.

Two tales of legacy effects on stream nutrient behaviour

NASA Astrophysics Data System (ADS)

Bieroza, M.; Heathwaite, A. L.

2017-12-01

Intensive agriculture has led to large-scale land use conversion, shortening of flow pathways and increased loads of nutrients in streams. This legacy results in gradual build-up of nutrients in agricultural catchments: in soil for phosphorus (biogeochemical legacy) and in the unsaturated zone for nitrate (hydrologic legacy), controlling the water quality in the long-term. Here we investigate these effects on phosphorus and nitrate stream concentrations using high-frequency (10-5 - 100 Hz) sampling with in situ wet-chemistry analysers and optical sensors. Based on our 5 year study, we observe that storm flow responses differ for both nutrients: phosphorus shows rapid increases (up to 3 orders of magnitude) in concentrations with stream flow, whereas nitrate shows both dilution and concentration effects with increasing flow. However, the range of nitrate concentrations change is narrow (up to 2 times the mean) and reflects chemostatic behaviour. We link these nutrient responses with their dominant sources and flow pathways in the catchment. Nitrate from agriculture (with the peak loading in 1983) is stored in the unsaturated zone of the Penrith Sandstone, which can reach up to 70 m depth. Thus nitrate legacy is related to a hydrologic time lag with long travel times in the unsaturated zone. Phosphorus is mainly sorbed to soil particles, therefore it is mobilised rapidly during rainfall events (biogeochemical legacy). The phosphorus stream response will however depend on how well connected is the stream to the catchment sources (driven by soil moisture distribution) and biogeochemical activity (driven by temperature), leading to both chemostatic and non-chemostatic responses, alternating on a storm-to-storm and seasonal basis. Our results also show that transient within-channel storage is playing an important role in delivery of phosphorus, providing an additional time lag component. These results show, that consistent agricultural legacy in the catchment (high historical loads of nutrients) has different effects on nutrients stream responses, depending on their dominant sources and pathways. Both types of time lags, biogeochemical for phosphorus and hydrologic for nitrate, need to be taken into account when designing and evaluating the effectiveness of the agri-environmental mitigation measures.

Physical stream habitat dynamics in Lower Bear Creek, northern Arkansas

USGS Publications Warehouse

Reuter, Joanna M.; Jacobson, Robert B.; Elliott, Caroline M.

2003-01-01

We evaluated the roles of geomorphic and hydrologic dynamics in determining physical stream habitat in Bear Creek, a stream with a 239 km2 drainage basin in the Ozark Plateaus (Ozarks) in northern Arkansas. During a relatively wet 12-month monitoring period, the geomorphology of Bear Creek was altered by a series of floods, including at least four floods with peak discharges exceeding a 1-year recurrence interval and another flood with an estimated 2- to 4-year recurrence interval. These floods resulted in a net erosion of sediment from the study reach at Crane Bottom at rates far in excess of other sites previously studied in the Ozarks. The riffle-pool framework of the study reach at Crane Bottom was not substantially altered by these floods, but volumes of habitat in riffles and pools changed. The 2- to 4-year flood scoured gravel from pools and deposited it in riffles, increasing the diversity of available stream habitat. In contract, the smaller floods eroded gravel from the riffles and deposited it in pools, possibly flushing fine sediment from the substrate but also decreasing habitat diversity. Channel geometry measured at the beginning of the study was use to develop a two-dimensional, finite-element hydraulic model at assess how habitat varies with hydrologic dynamics. Distributions of depth and velocity simulated over the range of discharges observed during the study (0.1 to 556 cubic meters per second, cms) were classified into habitat units based on limiting depths and Froude number criteria. The results indicate that the areas of habitats are especially sensitive to change to low to medium flows. Races (areas of swift, relatively deep water downstream from riffles) disappear completely at the lowest flows, and riffles (areas of swift, relatively shallow water) contract substantially in area. Pools also contract in area during low flow, but deep scours associated with bedrock outcrops sustain some pool area even at the lowest modeled flows. Modeled boundary shear stresses were used to evaluate which flows are responsible for the most mobilization of the bed, and therefore, habitat maintenance. Evaluation of the magnitude and frequency of bed-sediment entrainment shows that most of the habitat maintenance results from flows that occur on average about 4 to 7 days a year. Our analysis documents the geomorphic and hydrologic dynamics that form and maintain habitats in a warmwater stream in the Ozarks. The range of flows that occurs on this stream can be partitioned into those that sustain habitat by providing the combinations of depth and velocity that stream organisms live with most of the time, and those flows that surpass sediment entrainment thresholds, alter stream geomorphology, and therefore maintain habitat. The quantitative relations show sensitivity of habitats to flow variation, but do not address how flow may vary in the future, or the extent to which stream geomorphology may be affected by variations in sediment supply.

Techniques for estimating the magnitude and frequency of floods in rural basins of South Carolina, 1999

USGS Publications Warehouse

Feaster, Toby D.; Tasker, Gary D.

2002-01-01

Data from 167 streamflow-gaging stations in or near South Carolina with 10 or more years of record through September 30, 1999, were used to develop two methods for estimating the magnitude and frequency of floods in South Carolina for rural ungaged basins that are not significantly affected by regulation. Flood frequency estimates for 54 gaged sites in South Carolina were computed by fitting the water-year peak flows for each site to a log-Pearson Type III distribution. As part of the computation of flood-frequency estimates for gaged sites, new values for generalized skew coefficients were developed. Flood-frequency analyses also were made for gaging stations that drain basins from more than one physiographic province. The U.S. Geological Survey, in cooperation with the South Carolina Department of Transportation, updated these data from previous flood-frequency reports to aid officials who are active in floodplain management as well as those who design bridges, culverts, and levees, or other structures near streams where flooding is likely to occur. Regional regression analysis, using generalized least squares regression, was used to develop a set of predictive equations that can be used to estimate the 2-, 5-, 10-, 25-, 50-, 100-, 200-, and 500-year recurrence-interval flows for rural ungaged basins in the Blue Ridge, Piedmont, upper Coastal Plain, and lower Coastal Plain physiographic provinces of South Carolina. The predictive equations are all functions of drainage area. Average errors of prediction for these regression equations ranged from -16 to 19 percent for the 2-year recurrence-interval flow in the upper Coastal Plain to -34 to 52 percent for the 500-year recurrence interval flow in the lower Coastal Plain. A region-of-influence method also was developed that interactively estimates recurrence- interval flows for rural ungaged basins in the Blue Ridge of South Carolina. The region-of-influence method uses regression techniques to develop a unique relation between flow and basin characteristics for an individual watershed. This, then, can be used to estimate flows at ungaged sites. Because the computations required for this method are somewhat complex, a computer application was developed that performs the computations and compares the predictive errors for this method. The computer application includes the option of using the region-of-influence method, or the generalized least squares regression equations from this report to compute estimated flows and errors of prediction specific to each ungaged site. From a comparison of predictive errors using the region-of-influence method with those computed using the regional regression method, the region-of-influence method performed systematically better only in the Blue Ridge and is, therefore, not recommended for use in the other physiographic provinces. Peak-flow data for the South Carolina stations used in the regionalization study are provided in appendix A, which contains gaging station information, log-Pearson Type III statistics, information on stage-flow relations, and water-year peak stages and flows. For informational purposes, water-year peak-flow data for stations on regulated streams in South Carolina also are provided in appendix D. Other information pertaining to the regulated streams is provided in the text of the report.

Hydro-meteorological trends in the Gidabo catchment of the Rift Valley Lakes Basin of Ethiopia

NASA Astrophysics Data System (ADS)

Belihu, Mamuye; Abate, Brook; Tekleab, Sirak; Bewket, Woldeamlak

2018-04-01

The global and regional variability and changes of climate and stream flows are likely to have significant influence on water resource availability. The magnitude and impacts of climate variability and change differs spatially and temporally. This study examines the long term hydroclimatic changes, analyses of the hydro-climate variability and detect whether there exist significant trend or not in the Gidabo catchment, rift valley lakes basin of Ethiopia. Precipitation, temperature and stream flow time series data were used in monthly, seasonal and annual time scales. The precipitation and temperature data span is between 1982 and 2014 and that of stream flow is between 1976 and 2006. To detect trends the analysis were done by using Mann Kendal (MK), Sen's graphical method and to detect change point using the Pettit test. The comparison of trend analysis between MK trend test and Sen graphical method results depict mostly similar pattern. The annual rainfall trends exhibited a significant decrease by about 12 mm per year in the upstream, which is largely driven by the significant decrease in the peak season rainfall. The Pettit test revealed that the years 1997 and 2007 were the change points. It is noted that the rise of temperature over a catchment might have decreased the availability of soil moisture which resulted in less runoff. The temperature analyses also revealed that the catchment was getting warmer; particularly in the upstream. The minimum temperature trend showed a significant increase about 0.08°c per annum. There is generally a decreasing trend in stream flow. The monthly stream flow also exhibited a decreasing trend in February, March and September. The decline in annual and seasonal rainfall and the increase in temperature lead to more evaporation and directly affecting the stream flow negatively. This trend compounded with the growth of population and increasing demand for irrigation water exacerbates the competing demand for water resources. It thus calls for prudence in devising appropriate intervention in the planning and sustainable development of the basin water resources.

Development of a traveltime prediction equation for streams in Arkansas

USGS Publications Warehouse

Funkhouser, Jaysson E.; Barks, C. Shane

2004-01-01

During 1971 and 1981 and 2001 and 2003, traveltime measurements were made at 33 sample sites on 18 streams throughout northern and western Arkansas using fluorescent dye. Most measurements were made during steady-state base-flow conditions with the exception of three measurements made during near steady-state medium-flow conditions (for the study described in this report, medium-flow is approximately 100-150 percent of the mean monthly streamflow during the month the dye trace was conducted). These traveltime data were compared to the U.S. Geological Survey?s national traveltime prediction equation and used to develop a specific traveltime prediction equation for Arkansas streams. In general, the national traveltime prediction equation yielded results that over-predicted the velocity of the streams for 29 of the 33 sites measured. The standard error for the national traveltime prediction equation was 105 percent. The coefficient of determination was 0.78. The Arkansas prediction equation developed from a regression analysis of dye-tracing results was a significant improvement over the national prediction equation. This regression analysis yielded a standard error of 46 percent and a coefficient of determination of 0.74. The predicted velocities using this equation compared better to measured velocities. Using the variables in a regression analysis, the Arkansas prediction equation derived for the peak velocity in feet per second was: (Actual Equation Shown in report) In addition to knowing when the peak concentration will arrive at a site, it is of great interest to know when the leading edge of a contaminant plume will arrive. The traveltime of the leading edge of a contaminant plume indicates when a potential problem might first develop and also defines the overall shape of the concentration response function. Previous USGS reports have shown no significant relation between any of the variables and the time from injection to the arrival of the leading edge of the dye plume. For this report, the analysis of the dye-tracing data yielded a significant correlation between traveltime of the leading edge and traveltime of the peak concentration with an R2 value of 0.99. These data indicate that the traveltime of the leading edge can be estimated from: (Actual Equation Shown in Report)

Comparison Of Quantitative Precipitation Estimates Derived From Rain Gauge And Radar Derived Algorithms For Operational Flash Flood Support.

NASA Astrophysics Data System (ADS)

Streubel, D. P.; Kodama, K.

2014-12-01

To provide continuous flash flood situational awareness and to better differentiate severity of ongoing individual precipitation events, the National Weather Service Research Distributed Hydrologic Model (RDHM) is being implemented over Hawaii and Alaska. In the implementation process of RDHM, three gridded precipitation analyses are used as forcing. The first analysis is a radar only precipitation estimate derived from WSR-88D digital hybrid reflectivity, a Z-R relationship and aggregated into an hourly ¼ HRAP grid. The second analysis is derived from a rain gauge network and interpolated into an hourly ¼ HRAP grid using PRISM climatology. The third analysis is derived from a rain gauge network where rain gauges are assigned static pre-determined weights to derive a uniform mean areal precipitation that is applied over a catchment on a ¼ HRAP grid. To assess the effect of different QPE analyses on the accuracy of RDHM simulations and to potentially identify a preferred analysis for operational use, each QPE was used to force RDHM to simulate stream flow for 20 USGS peak flow events. An evaluation of the RDHM simulations was focused on peak flow magnitude, peak flow timing, and event volume accuracy to be most relevant for operational use. Results showed RDHM simulations based on the observed rain gauge amounts were more accurate in simulating peak flow magnitude and event volume relative to the radar derived analysis. However this result was not consistent for all 20 events nor was it consistent for a few of the rainfall events where an annual peak flow was recorded at more than one USGS gage. Implications of this indicate that a more robust QPE forcing with the inclusion of uncertainty derived from the three analyses may provide a better input for simulating extreme peak flow events.

Experimental aerodynamic heating to simulated space shuttle tiles in laminar and turbulent boundary layers with variable flow angles at a nominal Mach number of 7. M.S. Thesis - George Washington Univ., Nov. 1983

NASA Technical Reports Server (NTRS)

Avery, D. E.

1985-01-01

The heat transfer to simulated shuttle thermal protection system tiles was investigated experimentally by using a highly instrumented metallic thin wall tile arranged with other metal tiles in a staggered tile array. Cold wall heating rate data for laminar and turbulent flow were obtained in the Langley 8 foot high Temperature Tunnel at a nominal Mach number of 7, a nominal total temperature of 3300R, a free stream unit Reynolds number from 3.4 x 10 sup 5 to 2.2 10 sup 6 per foot, and a free stream dynamic pressure from 2.1 to 9.0 psia. Experimental data are presented to illustrate the effects of flow angularity and gap width on both local peak heating and overall heating loads. For the conditions of the present study, the results show that localized and total heating are sensitive to changes in flow angle only for the test conditions of turbulent boundary layer flow with high kinetic energy and that a flow angle from 30 deg to 50 deg will minimize the local heating.

Application of the Water Erosion Prediction Project (WEPP) Model to simulate streamflow in a PNW forest watershed

Treesearch

A. Srivastava; M. Dobre; E. Bruner; W. J. Elliot; I. S. Miller; J. Q. Wu

2011-01-01

Assessment of water yields from watersheds into streams and rivers is critical to managing water supply and supporting aquatic life. Surface runoff typically contributes the most to peak discharge of a hydrograph while subsurface flow dominates the falling limb of hydrograph and baseflow contributes to streamflow from shallow unconfined aquifers primarily during the...

Effects of landscape-based green infrastructure on stormwater ...

EPA Pesticide Factsheets

The development of impervious surfaces in urban and suburban catchments affects their hydrological behavior by decreasing infiltration, increasing peak hydrograph response following rainfall events, and ultimately increasing the total volume of water and mass of pollutants reaching streams. These changes have deleterious effects on downstream surface waters. Consequently, strategies to mitigate these impacts are now components of contemporary urban development and stormwater management. This study evaluates the effectiveness of landscape green infrastructure (GI) in reducing stormwater runoff volumes and controlling peak flows in four subdivision-scale suburban catchments (1.88 – 12.97 acres) in Montgomery County, MD, USA. Stormwater flow rates during runoff events were measured in five minute intervals at each catchment outlet. One catchment was built with GI vegetated swales on all parcels with the goal of intercepting, conveying, and infiltrating stormwater before it enters the sewer network. The remaining catchments were constructed with traditional gray infrastructure and “end-of-pipe” best management practices (BMPs) that treat stormwater before entering streams. This study compared characteristics of rainfall-runoff events at the green and gray infrastructure sites to understand their effects on suburban hydrology. The landscape GI strategy generally reduced rainfall-runoff ratios compared to gray infrastructure because of increased infiltration, ul

A joint probability approach for coincidental flood frequency analysis at ungauged basin confluences

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

Wang, Cheng

2016-03-12

A reliable and accurate flood frequency analysis at the confluence of streams is of importance. Given that long-term peak flow observations are often unavailable at tributary confluences, at a practical level, this paper presents a joint probability approach (JPA) to address the coincidental flood frequency analysis at the ungauged confluence of two streams based on the flow rate data from the upstream tributaries. One case study is performed for comparison against several traditional approaches, including the position-plotting formula, the univariate flood frequency analysis, and the National Flood Frequency Program developed by US Geological Survey. It shows that the results generatedmore » by the JPA approach agree well with the floods estimated by the plotting position and univariate flood frequency analysis based on the observation data.« less

Quantifying contributions to storm runoff through end-member mixing analysis and hydrologic measurements at the Panola Mountain research watershed (Georgia, USA)

USGS Publications Warehouse

Burns, Douglas A.; McDonnell, Jeffery J.; Hooper, R.P.; Peters, N.E.; Freer, J.E.; Kendall, C.; Beven, K.

2001-01-01

The geographic sources and hydrologic flow paths of stormflow in small catchments are not well understood because of limitations in sampling methods and insufficient resolution of potential end members. To address these limitations, an extensive hydrologic dataset was collected at a 10 ha catchment at Panola Mountain research watershed near Atlanta, GA, to quantify the contribution of three geographic sources of stormflow. Samples of stream water, runoff from an outcrop, and hillslope subsurface stormflow were collected during two rainstorms in the winter of 1996, and an end-member mixing analysis model that included five solutes was developed. Runoff from the outcrop, which occupies about one-third of the catchment area, contributed 50-55% of the peak streamflow during the 2 February rainstorm, and 80-85% of the peak streamflow during the 6-7 March rainstorm; it also contributed about 50% to total streamflow during the dry winter conditions that preceded the 6-7 March storm. Riparian groundwater runoff was the largest component of stream runoff (80-100%) early during rising streamflow and throughout stream recession, and contributed about 50% to total stream runoff during the 2 February storm, which was preceded by wet winter conditions. Hillslope runoff contributed 25-30% to peak stream runoff and 15-18% to total stream runoff during both storms. The temporal response of the three runoff components showed general agreement with hydrologic measurements from the catchment during each storm. Estimates of recharge from the outcrop to the riparian aquifer that were independent of model calculations indicated that storage in the riparian aquifer could account for the volume of rain that fell on the outcrop but did not contribute to stream runoff. The results of this study generally indicate that improvements in the ability of mixing models to describe the hydrologic response accurately in forested catchments may depend on better identification, and detailed spatial and temporal characterization of the mobile waters from the principal hydrologic source areas that contribute to stream runoff. Copyright ?? 2001 John Wiley & Sons, Ltd.

Direct experimental evidence of ion-ion co-stream instability excited in the sheath-presheath of Ar +He two-ion species plasma

NASA Astrophysics Data System (ADS)

Kella, Vara Prasad; Ghosh, Joydeep; Chattopadhyay, Prabal; Sharma, Devendra; Saxena, Yogesh

2017-10-01

Recent experimental measurements of ion flow speeds near the sheath edge of two-ion species plasma shows that, the ions reach the sheath edge with common sound speed other than their individual Bohm speeds at nearly equal ion concentrations. Baalrud et al., explain these results on the basis of ion-ion two-stream instability enhanced collisional friction between the ions. Some authors stipulate the existence of the instability indirectly, by measuring the ion flow speeds near the sheath edge. In these experiments, the instability is directly observed from the floating potential fluctuations from Langmuir probe placed near the sheath edge and from grid in Ar +He plasma. The frequency spectra shows broad band peaks with central frequency in the range 150-200 kHz. The intensity of the instability maximizes in the plasma produced with approximately equal ion concentrations of both the ion species. The frequency and amplitude of the peak decreases as the He+ to Ar+ concentration ratio decreases from unity. The phase velocity of the wave is measured as 11 +/-2 km/s and identified to be twice the ion-sound speed in the bulk ( 6.3 km/s), which is good agreement with earlier results of IAWs. The measured wave number and frequencies are compared with the theoretical dispersion relations. These observations confirm the existence of ion-ion co-stream instability in sheath-presheath of two-ion species plasma.

Investigating Land-Use Effects on Hydrologic Processes and Water Quality in a Complex Karst Hydro-Region of the Central United States

NASA Astrophysics Data System (ADS)

Hubbart, J. A.; Bulliner, E. A.; Freeman, G. W.; Chinnasamy, P.; Hosmer, G. W.; Scollan, D. P.; Stokely, T. D.

2009-12-01

A century of watershed studies verify that hydrologic and water quality responses to land-use varies substantially physiographically. In the Oak dominated, Missouri Ozark Karst hydrogeologic region of the Central U.S., catchment studies are needed to validate current forest best management practices (BMPs). Similarly, studies are necessary that quantify urban degraded freshwater resources and disassembled riparian zone form and function. Given that continued human population growth over the next several decades will place unprecedented demands on forested and urban water resources, it is imperative to confront contemporary forested watershed issues that encompass the wildland - urban interface. Studies were initiated in the fall of 2008 to: a) validate current riparian forest BMPs, b) quantify peak flows and microclimate alteration due to urbanization, and c) quantify stream connectivity to adjacent riparian floodplains. Study catchments are located in the urbanizing Hinkson Creek Watershed (HCW, 231km2) and the Baskett Wildlife Research and Education Area (BREA, 8.9 km2), both watersheds centrally located in Missouri. Hydroclimate stations were installed at five locations along Hinkson Creek partitioning forest, cropland, and urban environments (nested-scale study design), and two opposing forested stream reaches of the BREA. Climate in central Missouri is generally classified as humid continental, with annual mean temperature and precipitation of approximately 12.6 °C and 1050 mm respectively. Study catchments land use spans old growth mixed deciduous forest to rural pastureland and the growing urbanized center of Columbia, Mo (population exceeding 101,000). Soils are highly variable prairie-forest transitional to loamy till with a well developed clay pan of thin cherty clay and silty to sandy clay. Preliminary analyses of BREA riparian data (summer 2009) indicate that average temperatures for E-W oriented stream reaches are 0.3 °C lower than the N-S reaches and 2.2 °C lower than climate reference sites, reflecting the effects of canopy layers, density, and landscape physiography. Average net shortwave radiation for N-S oriented reach was 3.2% higher than the E-W reach, while maximum net longwave radiation was 62.4% lower. These results may hold important implications for on-going surface energy balance computations assessing canopy influence on stream water temperature. Preliminary analyses of HCW flow data indicate that forested headwater systems better attenuate peak flows of small precipitation events (< 0.80 mm) relative to current urban capabilities. Precipitation events greater than 1.0 mm result in peak rainfall time to peak flow decreased by as much as 13% in urban settings accompanied by at least 4 cm higher stage and 5 to 10% greater flow volume. Average air temperature in urbanized Columbia can exceed the forested region by as much as 15%, and precipitation events can be 50% greater in magnitude. Results from these complimentary studies will produce necessary datasets to improve hydrologic process understanding and develop improved guidelines and management tools in complex hydrophysiographic regions of Missouri and the Central U.S.

Determination of chloride in admixtures and aggregates for cement by a simple flow injection potentiometric system.

PubMed

Junsomboon, Jaroon; Jakmunee, Jaroon

2008-07-15

A simple flow injection system using three 3-way solenoid valves as an electric control injection valve and with a simple home-made chloride ion selective electrode based on Ag/AgCl wire as a sensor for determination of water soluble chloride in admixtures and aggregates for cement has been developed. A liquid sample or an extract was injected into a water carrier stream which was then merged with 0.1M KNO(3) stream and flowed through a flow cell where the solution will be in contact with the sensor, producing a potential change recorded as a peak. A calibration graph in range of 10-100 mg L(-1) was obtained with a detection limit of 2 mg L(-1). Relative standard deviations for 7 replicates injecting of 20, 60 and 90 mg L(-1) chloride solutions were 1.0, 1.2 and 0.6%, respectively. Sample throughput of 60 h(-1) was achieved with the consumption of 1 mL each of electrolyte solution and water carrier. The developed method was validated by the British Standard methods.

Flow-covariate prediction of stream pesticide concentrations.

PubMed

Mosquin, Paul L; Aldworth, Jeremy; Chen, Wenlin

2018-01-01

Potential peak functions (e.g., maximum rolling averages over a given duration) of annual pesticide concentrations in the aquatic environment are important exposure parameters (or target quantities) for ecological risk assessments. These target quantities require accurate concentration estimates on nonsampled days in a monitoring program. We examined stream flow as a covariate via universal kriging to improve predictions of maximum m-day (m = 1, 7, 14, 30, 60) rolling averages and the 95th percentiles of atrazine concentration in streams where data were collected every 7 or 14 d. The universal kriging predictions were evaluated against the target quantities calculated directly from the daily (or near daily) measured atrazine concentration at 32 sites (89 site-yr) as part of the Atrazine Ecological Monitoring Program in the US corn belt region (2008-2013) and 4 sites (62 site-yr) in Ohio by the National Center for Water Quality Research (1993-2008). Because stream flow data are strongly skewed to the right, 3 transformations of the flow covariate were considered: log transformation, short-term flow anomaly, and normalized Box-Cox transformation. The normalized Box-Cox transformation resulted in predictions of the target quantities that were comparable to those obtained from log-linear interpolation (i.e., linear interpolation on the log scale) for 7-d sampling. However, the predictions appeared to be negatively affected by variability in regression coefficient estimates across different sample realizations of the concentration time series. Therefore, revised models incorporating seasonal covariates and partially or fully constrained regression parameters were investigated, and they were found to provide much improved predictions in comparison with those from log-linear interpolation for all rolling average measures. Environ Toxicol Chem 2018;37:260-273. © 2017 SETAC. © 2017 SETAC.

Dynamics of current-use pesticides in the agricultural model basin

NASA Astrophysics Data System (ADS)

Perez, Debora; Okada, Elena; Menone, Mirta; Aparicio, Virginia; Costa, Jose Luis

2017-04-01

The southeast of the Pampas plains is a zone with intensive agricultural activities; this zone is highly irrigated by wetlands, rivers and many streams. The stream flow dynamics are strongly related to the regional humidity, mainly given by runoff water and phreatic surface level, and can change dramatically during storm events. In this sense, it is important to study the fluctuations in the loads and mass of current-use pesticide (CUPs) to examine the influence of hydrologic and seasonal variability on the response of pesticide levels. The objective of this work was to determine the maximum loads reached of ∑CUPs and mass of CUPs associated with the flow dynamic in surface waters of "El Crespo" stream. "El Crespo" stream is only influenced by farming activities, with intensive crop systems upstream (US) and extensive livestock production downstream (DS). It is an optimal site for pesticide monitoring studies since there are no urban or industrial inputs into the system. Water samples were collected monthly from October 2014 to October 2015 in the UP and DN sites using 1 L polypropylene bottles and stored at -20°C until analysis. The samples were analyzed using liquid chromatography coupled to a tandem mass spectrometer (UPLC-MS/MS). The stream flow was measured during the sampling times in both sites, covering low base-flow and high base-flow periods. The most frequently detected residues (>40%) were glyphosate and its metabolite AMPA, atrazine, acetochlor, metolachlor, 2,4-D, metsulfuron methyl, fluorocloridone, imidacloprid, tebuconazole and epoxiconazole. The mean concentrations of ∑CUPs during the sampling period were 1.62µg/L and 1.66µg/L in UP site and DN site, respectively. The highest levels of ∑CUPs were 4.03 µg/L in UP site during spring 2014 and 2.53 µg/L in DN site during winter 2014. The mass of ∑CUPs showed a direct relation between low base flow and high base flow periods. During high base flow during spring 2014, the stream discharge showed peak of 6.16 mt3/s and 6.77 mt3/s, in UP and DN site, respectively; where the total loads of ∑CUPs were 3.7 µg/L and 2.88 µg/L and the associated mass were 22.74 and 19.54 µg/s, in UP and DN site, respectively. During low base flow the discharge were lower than 1 mt3/s and the total loads of ∑CUPs were variable between 1-3 µg/L, but the mass never were higher than 3 µg/s. The intensive rain during the spring 2014, were the mainly factor that influence the stream flow and pesticide dynamics in the model basin

Numerical investigation of separated nozzle flows

NASA Technical Reports Server (NTRS)

Chen, C. L.; Chakravarthy, S. R.; Hung, C. M.

1994-01-01

A numerical study of axisymmetric overexpanded nozzle is presented. The flow structure of the startup and throttle-down processes are examined. During the impulsive startup process, observed flow features include the Mach disk, separation shock, Mach stem, vortex core, contact surface, slip stream, initial shock front, and shocklet. Also the movement of the Mach disk is not monotonical in the downstream direction. For a range of pressure ratios, hysteresis phenomenon occurs; different solutions were obtained depending on different processes. Three types of flow structures were observed. The location of separation point and the lower end turning point of hysteresis are closely predicted. A high peak of pressure is associated with the nozzle flow reattachment. The reversed vortical structure and affects engine performance.

Phosphorus loading to tropical rain forest streams after clear-felling and burning in Sabah, Malaysia

NASA Astrophysics Data System (ADS)

Malmer, Anders

1996-07-01

Most estimates of P export from natural or disturbed humid tropical ecosystems by streams have been based only on export of dissolved P, even though P often is limiting and can be expected to be strongly associated to particles. Therefore loss of ignition (LOI) and particulate P (Ppart) analyses were made on organic and inorganic detritus resulting from surface erosion and on stream-suspended sediments in an undisturbed rain forest (control), as well as during and after conversion of rain forest into forest plantation. Control forest surface erosion and stream sediments consisted mainly of organics, and dissolved P (Pdiss) dominated over Ppart in stream water. The same relation was found after conversion, with a maximum mean Pdiss/Ppart ratio of up to 10 after burning, compared with 2-2.5 for control forests. This larger difference was assumed to depend on PO4 dissolved from ashes to larger concentrations than could be adsorbed during the short time (<1 hour) to reach peak flow during rainstorms.

Influence of geomorphological properties and stage on in-stream travel time

NASA Astrophysics Data System (ADS)

Åkesson, Anna; Wörman, Anders

2014-05-01

The travel time distribution within stream channels is known to vary non-linearly with stage (discharge), depending on the combined effects of geomorphologic, hydrodynamic and kinematic dispersions. This non-linearity, implying that stream network travel time generally decreases with increasing discharge is a factor that is important to account for in hydrological modelling - especially when making peak flow predictions where uncertainty is often high and large values can be at risk. Through hydraulic analysis of several stream networks, we analyse how travel time distributions varies with discharge. The principal focus is the coupling to the geomorphologic properties of stream networks with the final goal being to use this physically based information as a parameterisation tool of the streamflow component of hydrologic models. For each of the studied stream networks, a 1D, steady-state, distributed routing model was set up to determine the velocities in each reach during different flow conditions. Although the model (based in the Manning friction formula) is built on the presence of uniform conditions within sub-reaches, the model can in the stream network scale be considered to include effects of non-uniformity as supercritical conditions in sections of the stream network give rise to backwater effects that reduce the flow velocities in upstream reaches in the stream. By coupling the routing model to a particle tracking routine tracing water "parcels" through the stream network, the average travel time within the stream network can be determined quantitatively for different flow conditions. The data used to drive the model is digitised stream network maps, topographical data (DEMs). The model is not calibrated in any way, but is run for with different sets of parameters representing a span of possible friction coefficients and cross-sectional geometries as this information is not generally known. The routing model is implemented in several different stream networks (representing catchments of the spatial scale of a few hundred km2) in different geographic regions in Sweden displaying different geomorphological properties. Results show that the geomorphological properties (data that is often available in the form of maps and/or DEMs) of individual stream networks have major influence on the stream network travel times. By coupling the geomorphological information to general expressions for stage dependency, catchment-specific relationships of how the travel times within stream networks can be determined. Basing the parameterisation procedure of a hydrological model in physical catchment properties and process understanding rather than statistical parameterisation (based in how a catchment has responded in the past) - is believed to lead to more reliable hydrological predictions - during extreme conditions as well as during changing conditions such as climate change and landscape modifications, and/or when making predictions in ungauged basins.

Regional statistical assessment of WRF-Hydro and IFC Model stream Flow uncertainties over the State of Iowa

NASA Astrophysics Data System (ADS)

ElSaadani, M.; Quintero, F.; Goska, R.; Krajewski, W. F.; Lahmers, T.; Small, S.; Gochis, D. J.

2015-12-01

This study examines the performance of different Hydrologic models in estimating peak flows over the state of Iowa. In this study I will compare the output of the Iowa Flood Center (IFC) hydrologic model and WRF-Hydro (NFIE configuration) to the observed flows at the USGS stream gauges. During the National Flood Interoperability Experiment I explored the performance of WRF-Hydro over the state of Iowa using different rainfall products and the resulting hydrographs showed a "flashy" behavior of the model output due to lack of calibration and bad initial flows due to short model spin period. I would like to expand this study by including a second well established hydrologic model and include more rain gauge vs. radar rainfall direct comparisons. The IFC model is expected to outperform WRF-Hydro's out of the box results, however, I will test different calibration options for both the Noah-MP land surface model and RAPID, which is the routing component of the NFIE-Hydro configuration, to see if this will improve the model results. This study will explore the statistical structure of model output uncertainties across scales (as a function of drainage areas and/or stream orders). I will also evaluate the performance of different radar-based Quantitative Precipitation Estimation (QPE) products (e.g. Stage IV, MRMS and IFC's NEXRAD based radar rainfall product. Different basins will be evaluated in this study and they will be selected based on size, amount of rainfall received over the basin area and location. Basin location will be an important factor in this study due to our prior knowledge of the performance of different NEXRAD radars that cover the region, this will help observe the effect of rainfall biases on stream flows. Another possible addition to this study is to apply controlled spatial error fields to rainfall inputs and observer the propagation of these errors through the stream network.

Preferential flow estimates to an agricultural tile drain with implications for glyphosate transport

USGS Publications Warehouse

Stone, W.W.; Wilson, J.T.

2006-01-01

Agricultural subsurface drains, commonly referred to as tile drains, are potentially significant pathways for the movement of fertilizers and pesticides to streams and ditches in much of the Midwest. Preferential flow in the unsaturated zone provides a route for water and solutes to bypass the soil matrix and reach tile drains faster than predicted by traditional displacement theory. This paper uses chloride concentrations to estimate preferential flow contributions to a tile drain during two storms in May 2004. Chloride, a conservative anion, was selected as the tracer because of differences in chloride concentrations between the two sources of water to the tile drain, preferential and matrix flow. A strong correlation between specific conductance and chloride concentration provided a mechanism to estimate chloride concentrations in the tile drain throughout the storm hydrographs. A simple mixing analysis was used to identify the preferential flow component of the storm hydrograph. During two storms, preferential flow contributed 11 and 51% of total storm tile drain flow; the peak contributions, 40 and 81%, coincided with the peak tile drain flow. Positive relations between glyphosate [N-(phosphonomethyl)glycine] concentrations and preferential flow for the two storms suggest that preferential flow is an important transport pathway to the tile drain. ?? ASA, CSSA, SSSA.

A probabilistic approach to quantifying hydrologic thresholds regulating migration of adult Atlantic salmon into spawning streams

NASA Astrophysics Data System (ADS)

Lazzaro, G.; Soulsby, C.; Tetzlaff, D.; Botter, G.

2017-03-01

Atlantic salmon is an economically and ecologically important fish species, whose survival is dependent on successful spawning in headwater rivers. Streamflow dynamics often have a strong control on spawning because fish require sufficiently high discharges to move upriver and enter spawning streams. However, these streamflow effects are modulated by biological factors such as the number and the timing of returning fish in relation to the annual spawning window in the fall/winter. In this paper, we develop and apply a novel probabilistic approach to quantify these interactions using a parsimonious outflux-influx model linking the number of female salmon emigrating (i.e., outflux) and returning (i.e., influx) to a spawning stream in Scotland. The model explicitly accounts for the interannual variability of the hydrologic regime and the hydrological connectivity of spawning streams to main rivers. Model results are evaluated against a detailed long-term (40 years) hydroecological data set that includes annual fluxes of salmon, allowing us to explicitly assess the role of discharge variability. The satisfactory model results show quantitatively that hydrologic variability contributes to the observed dynamics of salmon returns, with a good correlation between the positive (negative) peaks in the immigration data set and the exceedance (nonexceedance) probability of a threshold flow (0.3 m3/s). Importantly, model performance deteriorates when the interannual variability of flow regime is disregarded. The analysis suggests that flow thresholds and hydrological connectivity for spawning return represent a quantifiable and predictable feature of salmon rivers, which may be helpful in decision making where flow regimes are altered by water abstractions.

Expression of Geochemical Controls on Water Quality in Loch Vale, Rocky Mountain National Park

NASA Astrophysics Data System (ADS)

Podzorski, H.; Navarre-Sitchler, A.; Stets, E.; Clow, D. W.

2017-12-01

Relationships between concentrations of rock weathering products and discharge provide insight into the interactions between climate and solute dynamics. This concentration-discharge (C-Q) relationship is especially interesting in high alpine regions, due to their susceptibility to changes in the timing and magnitude of snowmelt. Previous studies looking at C-Q relationships have concluded that concentrations of conservative solutes remain relatively constant as discharge varies; however, these results may be due to relatively small sample sizes, especially at higher discharge values. Using water chemistry data collected regularly by the U.S. Geological Survey from Loch Vale, a high-elevation catchment in Rocky Mountain National Park, C-Q relationships were examined to determine possible geochemical controls on stream solute concentrations. A record of over 20 years of C-Q data resulted in a pattern that shows little variation in conservative solute concentrations during base flow and larger variations in concentrations around peak discharge. This observed pattern is consistent with accumulation of solutes in pore water during base flow, which are then flushed out and diluted by snowmelt. Further evidence of this flushing out mechanism is found in patterns of hysteresis that are present in annual C-Q relationships. Before peak discharge, concentrations of weathering products are higher than after peak discharge at similar values of discharge. Based on these observations, we hypothesize that the geochemical processes controlling stream chemistry vary by season. During the winter, solute concentrations are transport-limited due to slow subsurface flushing resulting in concentrations that are effectively constant and close to equilibrium. During the spring and summer, concentrations drop sharply after peak discharge due to a combination of dilution and reaction-limited processes under conditions with faster subsurface flow and continued snowmelt. This study provides insight into seasonal geochemical controls on conservative solute concentrations that can be overlooked with small, or seasonally biased, data sets.

After flow control: The steps taken by Dade County to ensure continued operation of its solid waste management system

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

Mauriello, P.J.; Ragbeer, D.

1997-12-01

In the wake of the U.S. Supreme Court decision in the Carbone vs. Clarkstown case striking down waste flow control as unconstitutional, Dade County, Florida, one of the most severely impacted communities in the nation, has managed to stabilize its waste stream and balance its solid waste department finances; although the road taken to restabilization has been a difficult one. At its peak in 1995, Dade County experienced an annual loss of solid waste in excess of 1,000,000 tons, or over 40 percent of the waste stream normally handled by the County. This diversion of waste was accompanied by amore » net revenue loss of $30 million per year. The County lost its ability to plan for future capacity needs, or to assure sufficient future waste flows to meet its put-or-pay obligation to the County`s Resources Recovery plant operator. The County`s solid waste management system bonds were downgraded by Moody`s Investors Service and Standard and Poors. With the help of a special solid waste management team, appointed by the County Manager, the department was able to rightsize its waste disposal operations to fit its reduced waste flows, stabilize its waste stream, and develop strategies to solve its long-term funding shortfall.« less

Mapping spatial patterns of stream power and channel change along a gravel-bed river in northern Yellowstone

NASA Astrophysics Data System (ADS)

Lea, Devin M.; Legleiter, Carl J.

2016-01-01

Stream power represents the rate of energy expenditure along a river and can be calculated using topographic data acquired via remote sensing or field surveys. This study sought to quantitatively relate temporal changes in the form of Soda Butte Creek, a gravel-bed river in northeastern Yellowstone National Park, to stream power gradients along an 8-km reach. Aerial photographs from 1994 to 2012 and ground-based surveys were used to develop a locational probability map and morphologic sediment budget to assess lateral channel mobility and changes in net sediment flux. A drainage area-to-discharge relationship and DEM developed from LiDAR data were used to obtain the discharge and slope values needed to calculate stream power. Local and lagged relationships between mean stream power gradient at median peak discharge and volumes of erosion, deposition, and net sediment flux were quantified via spatial cross-correlation analyses. Similarly, autocorrelations of locational probabilities and sediment fluxes were used to examine spatial patterns of sediment sources and sinks. Energy expended above critical stream power was calculated for each time period to relate the magnitude and duration of peak flows to the total volumetric change in each time increment. Collectively, we refer to these methods as the stream power gradient (SPG) framework. The results of this study were compromised by methodological limitations of the SPG framework and revealed some complications likely to arise when applying this framework to small, wandering, gravel-bed rivers. Correlations between stream power gradients and sediment flux were generally weak, highlighting the inability of relatively simple statistical approaches to link sub-budget cell-scale sediment dynamics to larger-scale driving forces such as stream power gradients. Improving the moderate spatial resolution techniques used in this study and acquiring very-high resolution data from recently developed methods in fluvial remote sensing could help improve understanding of the spatial organization of stream power, sediment transport, and channel change in dynamic natural rivers.

Component flow processes at four streams in the Catskill Mountains, New York, analysed using episodic concentration/discharge relationship

USGS Publications Warehouse

Evans, C.; Davies, T.D.; Murdoch, Peter S.

1999-01-01

Plots of solute concentration against discharge have been used to relate stream hydrochemical variations to processes of flow generation, using data collected at four streams in the Catskill Mountains, New York, during the Episodic Response Project of the US Environmental Protection Agency. Results suggest that a two-component system of shallow and deep saturated subsurface flow, in which the two components respond simultaneously during hydrologic events, may be applicable to the study basins. Using a large natural sea-salt sodium input as a tracer for precipitation, it is argued that an additional distinction can be made between pre-event and event water travelling along the shallow subsurface flow path. Pre-event water is thought to be displaced by infiltrating event water, which becomes dominant on the falling limb of the hydrograph. Where, as appears to be the case for sulfate, a solute equilibrates rapidly within the soil, the pre-event-event water distinction is unimportant. However, for some solutes there are clear and consistent compositional differences between water from the two sources, evident as a hysteresis loop in concentration-discharge plots. Nitrate and acidity, in particular, appear to be elevated in event water following percolation through the organic horizon. Consequently, the most acidic, high nitrate conditions during an episode generally occur after peak discharge. A simple conceptual model of episode runoff generation is presented on the basis of these results.Plots of solute concentration against discharge have been used to relate stream hydrochemical variations to processes of flow generation, using data collected at four streams in the Catskill Mountains, New York, during the Episodic Response Project of the US Environmental Protection Agency. Results suggest that a two-component system of shallow and deep saturated subsurface flow, in which the two components respond simultaneously during hydrologic events, may be applicable to the study basins. Using a large natural sea-salt sodium input as a tracer for precipitation, it is argued that an additional distinction can be made between pre-event and event water travelling along the shallow subsurface flow path. Pre-event water is thought to be displaced by infiltrating event water, which becomes dominant on the falling limb of the hydrograph. Where, as appears to be the case for sulfate, a solute equilibrates rapidly within the soil, the pre-event - event water distinction is unimportant. However, for some solutes there are clear and consistent compositional differences between water from the two sources, evident as a hysteresis loop in concentration-discharge plots. Nitrate and acidity, in particular, appear to be elevated in event water following percolation through the organic horizon. Consequently, the most acidic, high nitrate conditions during an episode generally occur after peak discharge. A simple conceptual model of episode runoff generation is presented on the basis of these results.

Ground-based thermography of fluvial systems at low and high discharge reveals potential complex thermal heterogeneity driven by flow variation and bioroughness

USGS Publications Warehouse

Cardenas, M.B.; Harvey, J.W.; Packman, A.I.; Scott, D.T.

2008-01-01

Temperature is a primary physical and biogeochemical variable in aquatic systems. Field-based measurement of temperature at discrete sampling points has revealed temperature variability in fluvial systems, but traditional techniques do not readily allow for synoptic sampling schemes that can address temperature-related questions with broad, yet detailed, coverage. We present results of thermal infrared imaging at different stream discharge (base flow and peak flood) conditions using a handheld IR camera. Remotely sensed temperatures compare well with those measured with a digital thermometer. The thermal images show that periphyton, wood, and sandbars induce significant thermal heterogeneity during low stages. Moreover, the images indicate temperature variability within the periphyton community and within the partially submerged bars. The thermal heterogeneity was diminished during flood inundation, when the areas of more slowly moving water to the side of the stream differed in their temperature. The results have consequences for thermally sensitive hydroelogical processes and implications for models of those processes, especially those that assume an effective stream temperature. Copyright ?? 2008 John Wiley & Sons, Ltd.

Improvement in precipitation-runoff model simulations by recalibration with basin-specific data, and subsequent model applications, Onondaga Lake Basin, Onondaga County, New York

USGS Publications Warehouse

Coon, William F.

2011-01-01

Simulation of streamflows in small subbasins was improved by adjusting model parameter values to match base flows, storm peaks, and storm recessions more precisely than had been done with the original model. Simulated recessional and low flows were either increased or decreased as appropriate for a given stream, and simulated peak flows generally were lowered in the revised model. The use of suspended-sediment concentrations rather than concentrations of the surrogate constituent, total suspended solids, resulted in increases in the simulated low-flow sediment concentrations and, in most cases, decreases in the simulated peak-flow sediment concentrations. Simulated orthophosphate concentrations in base flows generally increased but decreased for peak flows in selected headwater subbasins in the revised model. Compared with the original model, phosphorus concentrations simulated by the revised model were comparable in forested subbasins, generally decreased in developed and wetland-dominated subbasins, and increased in agricultural subbasins. A final revision to the model was made by the addition of the simulation of chloride (salt) concentrations in the Onondaga Creek Basin to help water-resource managers better understand the relative contributions of salt from multiple sources in this particular tributary. The calibrated revised model was used to (1) compute loading rates for the various land types that were simulated in the model, (2) conduct a watershed-management analysis that estimated the portion of the total load that was likely to be transported to Onondaga Lake from each of the modeled subbasins, (3) compute and assess chloride loads to Onondaga Lake from the Onondaga Creek Basin, and (4) simulate precolonization (forested) conditions in the basin to estimate the probable minimum phosphorus loads to the lake.

The StreamCat Dataset: Accumulated Attributes for NHDPlusV2 Catchments (Version 2.1) for the Conterminous United States: Dam Density and Storage Volume

EPA Pesticide Factsheets

This dataset represents the dam density and storage volumes within individual, local NHDPlusV2 catchments and upstream, contributing watersheds based on National Inventory of Dams (NID) data. Attributes were calculated for every local NHDPlusV2 catchment and accumulated to provide watershed-level metrics.(See Supplementary Info for Glossary of Terms) The NID database contains information about the dam??s location, size, purpose, type, last inspection, regulatory facts, and other technical data. Structures on streams reduce the longitudinal and lateral hydrologic connectivity of the system. For example, impoundments above dams slow stream flow, cause deposition of sediment and reduce peak flows. Dams change both the discharge and sediment supply of streams, causing channel incision and bed coarsening downstream. Downstream areas are often sediment deprived, resulting in degradation, i.e., erosion of the stream bed and stream banks. This database was improved upon by locations verified by work from the USGS National Map (Jeff Simley Group). It was observed that some dams, some of them major and which do exist, were not part of the 2009 NID, but were represented in the USGS National Map dataset, and had been in the 2006 NID. Approximately 1,100 such dams were added, based on the USGS National Map lat/long and the 2006 NID attributes (dam height, storage, etc.) Finally, as clean-up, a) about 600 records with duplicate NIDID were removed, and b) about 300 reco

High-resolution droplet-based fractionation of nano-LC separations onto microarrays for MALDI-MS analysis.

PubMed

Küster, Simon K; Pabst, Martin; Jefimovs, Konstantins; Zenobi, Renato; Dittrich, Petra S

2014-05-20

We present a robust droplet-based device, which enables the fractionation of ultralow flow rate nanoflow liquid chromatography (nano-LC) eluate streams at high frequencies and high peak resolution. This is achieved by directly interfacing the separation column to a micro T-junction, where the eluate stream is compartmentalized into picoliter droplets. This immediate compartmentalization prevents peak dispersion during eluate transport and conserves the chromatographic performance. Subsequently, nanoliter eluate fractions are collected at a rate of one fraction per second on a high-density microarray to retain the separation with high temporal resolution. Chromatographic separations of up to 45 min runtime can thus be archived on a single microarray possessing 2700 sample spots. The performance of this device is demonstrated by fractionating the separation of a tryptic digest of a known protein mixture onto the microarray chip and subsequently analyzing the sample archive using matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS). Resulting peak widths are found to be significantly reduced compared to standard continuous flow spotting technologies as well as in comparison to a conventional nano-LC-electrospray ionization-mass spectrometry interface. Moreover, we demonstrate the advantage of our high-definition nanofractionation device by applying two different MALDI matrices to all collected fractions in an alternating fashion. Since the information that is obtained from a MALDI-MS measurement depends on the choice of MALDI matrix, we can extract complementary information from neighboring spots containing almost identical composition but different matrices.

Application of two- and three-dimensional computational fluid dynamics models to complex ecological stream flows

NASA Astrophysics Data System (ADS)

Shen, Yi; Diplas, Panayiotis

2008-01-01

SummaryComplex flow patterns generated by irregular channel topography, such as boulders, submerged large woody debris, riprap and spur dikes, provide unique habitat for many aquatic organisms. Numerical modeling of the flow structures surrounding these obstructions is challenging, yet it represents an important tool for aquatic habitat assessment. In this study, the ability of two- (2-D) and three-dimensional (3-D) computational fluid dynamics models to reproduce these localized complex flow features is examined. The 3-D model is validated with laboratory data obtained from the literature for the case of a flow around a hemisphere under emergent and submerged conditions. The performance of the 2-D and 3-D models is then evaluated by comparing the numerical results with field measurements of flow around several boulders located at a reach of the Smith River, a regulated mountainous stream, obtained at base and peak flows. Close agreement between measured values and the velocity profiles predicted by the two models is obtained outside the wakes behind the hemisphere and boulders. However, the results suggest that in the vicinity of these obstructions the 3-D model is better suited for reproducing the circulation flow behavior at both low and high discharges. Application of the 2-D and 3-D models to meso-scale stream flows of ecological significance is furthermore demonstrated by using a recently developed spatial hydraulic metric to quantify flow complexity surrounding a number of brown trout spawning sites. It is concluded that the 3-D model can provide a much more accurate description of the heterogeneous velocity patterns favored by many aquatic species over a broad range of flows, especially under deep flow conditions when the various obstructions are submerged. Issues pertaining to selection of appropriate models for a variety of flow regimes and potential implication of the 3-D model on the development of better habitat suitability criteria are discussed. The research suggests ways of improving the modeling practices for ecosystem management studies.

Can isolated and riparian wetlands mitigate the impact of climate change on watershed hydrology? A case study approach.

PubMed

Fossey, M; Rousseau, A N

2016-12-15

The effects of wetlands on stream flows are well established, namely mitigating flow regimes through water storage and slow water release. However, their effectiveness in reducing flood peaks and sustaining low flows is mainly driven by climate conditions and wetland type with respect to their connectivity to the hydrographic network (i.e. isolated or riparian wetlands). While some studies have demonstrated these hydrological functions/services, few of them have focused on the benefits to the hydrological regimes and their evolution under climate change (CC) and, thus, some gaps persist. The objective of this study was to further advance our knowledge with that respect. The PHYSITEL/HYDROTEL modelling platform was used to assess current and future states of watershed hydrology of the Becancour and Yamaska watersheds, Quebec, Canada. Simulation results showed that CC will induce similar changes on mean seasonal flows, namely larger and earlier spring flows leading to decreases in summer and fall flows. These expected changes will have different effects on 20-year and 100-year peak flows with respect to the considered watershed. Nevertheless, conservation of current wetland states should: (i) for the Becancour watershed, mitigate the potential increase in 2-year, 20-year and 100-year peak flows; and (ii) for the Yamaska watershed, accentuate the potential decrease in the aforementioned indicators. However, any loss of existing wetlands would be detrimental for 7-day 2-year and 10-year as well as 30-day 5-year low flows. Copyright © 2016 Elsevier Ltd. All rights reserved.

Traveltime and longitudinal dispersion in Illinois streams

USGS Publications Warehouse

Graf, J.B.

1984-01-01

Twenty-seven measurements of traveltime and longitudinal dispersion in 10 Illinois streams provide data needed for estimating traveltime of peak concentration of a conservative solute, traveltime of the leading edge of a solute cloud, peak concentration resulting from a given quantity of solute, and passage time of solute past a given point on a stream for both measured and unmeasured streams. Traveltime of peak concentration and of the leading edge of the cloud are related to discharge at the downstream end of the reach, distance of travel, and the fraction of the time that discharge at a given location on the stream is equaled or exceeded. Peak concentration and passage time are best estimated from the relation of each to traveltime. In measured streams, dispersion efficiency is greater than that predicted by Fickian diffusion theory. The rate of decrease in peak concentration with traveltime is about equal to the rate of increase in passage time. Average velocity in a stream reach, given by the velocity of the center of solute mass in that reach, also can be estimated from an equation developed from measured values. (USGS)

A comparison of methods for deriving solute flux rates using long-term data from streams in the mirror lake watershed

USGS Publications Warehouse

Bukaveckas, P.A.; Likens, G.E.; Winter, T.C.; Buso, D.C.

1998-01-01

Calculation of chemical flux rates for streams requires integration of continuous measurements of discharge with discrete measurements of solute concentrations. We compared two commonly used methods for interpolating chemistry data (time-averaging and flow-weighting) to determine whether discrepancies between the two methods were large relative to other sources of error in estimating flux rates. Flux rates of dissolved Si and SO42- were calculated from 10 years of data (1981-1990) for the NW inlet and Outlet of Mirror Lake and for a 40-day period (March 22 to April 30, 1993) during which we augmented our routine (weekly) chemical monitoring with collection of daily samples. The time-averaging method yielded higher estimates of solute flux during high-flow periods if no chemistry samples were collected corresponding to peak discharge. Concentration-discharge relationships should be used to interpolate stream chemistry during changing flow conditions if chemical changes are large. Caution should be used in choosing the appropriate time-scale over which data are pooled to derive the concentration-discharge regressions because the model parameters (slope and intercept) were found to be sensitive to seasonal and inter-annual variation. Both methods approximated solute flux to within 2-10% for a range of solutes that were monitored during the intensive sampling period. Our results suggest that errors arising from interpolation of stream chemistry data are small compared with other sources of error in developing watershed mass balances.

Fluvial process and the establishment of bottomland trees

USGS Publications Warehouse

Scott, Michael L.; Friedman, Jonathan M.; Auble, Gregor T.

1996-01-01

The relation between streamflow and establishment of bottomland trees is conditioned by the dominant fluvial process or processes acting along a stream. For successful establishment, cottonwoods, poplars, and willows require bare, moist surfaces protected from disturbance. Channel narrowing, channel meandering, and flood deposition promote different spatial and temporal patterns of establishment. During channel narrowing, the site requirements are met on portions of the bed abandoned by the stream, and establishment is associated with a period of low flow lasting one to several years. During channel meandering, the requirements are met on point bars following moderate or higher peak flows. Following flood deposition, the requirements are met on flood deposits ;high above the channel bed. Flood deposition can occur along most streams, but where a channel is constrained by a narrow valley, this process may be the only mechanism that can produce a bare, moist surface high enough to be safe from future disturbance. Because of differences in local bedrock, tributary influence, or geologic history, two nearby reaches of the same stream may be dominated by different fluvial processes and have different spatial and temporal patterns of trees. We illustrate this phenomenon with examples from forests of plains cottonwood (Populus deltoides ssp. monilifera) along meandering and constrained reaches of the Missouri River in Montana.

Inflow velocities of cold flows streaming into massive galaxies at high redshifts

NASA Astrophysics Data System (ADS)

Goerdt, Tobias; Ceverino, Daniel

2015-07-01

We study the velocities of the accretion along streams from the cosmic web into massive galaxies at high redshift with the help of three different suites of AMR hydrodynamical cosmological simulations. The results are compared to free-fall velocities and to the sound speeds of the hot ambient medium. The sound speed of the hot ambient medium is calculated using two different methods to determine the medium's temperature. We find that the simulated cold stream velocities are in violent disagreement with the corresponding free-fall profiles. The sound speed is a better albeit not always correct description of the cold flows' velocity. Using these calculations as a first order approximation for the gas inflow velocities vinflow = 0.9 vvir is given. We conclude from the hydrodynamical simulations as our main result that the velocity profiles for the cold streams are constant with radius. These constant inflow velocities seem to have a `parabola-like' dependency on the host halo mass in units of the virial velocity that peaks at Mvir = 1012 M⊙ and we also propose that the best-fitting functional form for the dependency of the inflow velocity on the redshift is a square root power-law relation: v_inflow ∝ √{z + 1} v_vir.

Mapping Spatial Distributions of Stream Power and Channel Change along a Gravel-Bed River in Northern Yellowstone

NASA Astrophysics Data System (ADS)

Lea, D. M.; Legleiter, C. J.

2014-12-01

Stream power represents the rate of energy expenditure along a river and can be calculated using topographic data acquired via remote sensing. This study used remotely sensed data and field measurements to quantitatively relate temporal changes in the form of Soda Butte Creek, a gravel-bed river in northeastern Yellowstone National Park, to stream power gradients along an 8 km reach. Aerial photographs from 1994-2012 and cross-section surveys were used to assess lateral channel mobility and develop a morphologic sediment budget for quantifying net sediment flux for a series of budget cells. A drainage area-to-discharge relationship and digital elevation model (DEM) developed from LiDAR data were used to obtain the discharge and slope values, respectively, needed to calculate stream power. Local and lagged relationships between mean stream power gradient at median peak discharge and volumes of erosion, deposition, and net sediment flux were quantified via spatial cross-correlation analyses. Similarly, autocorrelations of locational probabilities and sediment fluxes were used to examine spatial patterns of channel mobility and sediment transfer. Energy expended above critical stream power was calculated for each time period to relate the magnitude and duration of peak flows to the total volume of sediment eroded or deposited during each time increment. Our results indicated a lack of strong correlation between stream power gradients and sediment flux, which we attributed to the geomorphic complexity of the Soda Butte Creek watershed and the inability of our relatively simple statistical approach to link sediment dynamics expressed at a sub-budget cell scale to larger-scale driving forces such as stream power gradients. Future studies should compare the moderate spatial resolution techniques used in this study to very-high resolution data acquired from new fluvial remote sensing technologies to better understand the amount of error associated with stream power, sediment transport, and channel change calculated from historical datasets.

Mapping spatial patterns of stream power and channel change along a gravel-bed river in northern Yellowstone

NASA Astrophysics Data System (ADS)

Lea, Devin M.

Stream power represents the rate of energy expenditure along a river and can be calculated using topographic data acquired via remote sensing or field surveys. This study used remote sensing and GIS tools along with field data to quantitatively relate temporal changes in the form of Soda Butte Creek, a gravel-bed river in northeastern Yellowstone National Park, to stream power gradients along an 8 km reach. Aerial photographs from 1994-2012 and cross-section surveys were used to develop a locational probability map and morphologic sediment budget to assess lateral channel mobility and changes in net sediment flux. A drainage area-to-discharge relationship and digital elevation model (DEM) developed from light detection and ranging (LiDAR) data were used to obtain the discharge and slope values needed to calculate stream power. Local and lagged relationships between mean stream power gradient at median peak discharge and volumes of erosion, deposition, and net sediment flux were quantified via spatial cross-correlation analyses. Similarly, autocorrelations of locational probabilities and sediment fluxes were used to examine spatial patterns of sediment sources and sinks. Energy expended above critical stream power was calculated for each time period to relate the magnitude and duration of peak flows to the total volumetric change in each time increment. Results indicated a lack of strong correlation between stream power gradients and sediment response, highlighting the geomorphic complexity of Soda Butte Creek and the inability of relatively simple statistical approaches to link sub-budget cell-scale sediment dynamics to larger-scale driving forces such as stream power gradients. Improving the moderate spatial resolution techniques used in this study and acquiring very-high resolution data from recently developed methods in fluvial remote sensing could help improve understanding of the spatial organization of stream power, sediment transport, and channel change in dynamic natural rivers.

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.

Effects of Large Wood on River-Floodplain Connectivity in a Headwater Appalachian Stream

NASA Astrophysics Data System (ADS)

Keys, T.; Govenor, H.; Jones, C. N.; Hession, W. C.; Scott, D.; Hester, E. T.

2017-12-01

Large wood (LW) plays an important, yet often undervalued role in stream ecosystems. Traditionally, LW has been removed from streams for aesthetic, navigational, and flood mitigation purposes. However, extensive research over the last three decades has directly linked LW to critical ecosystem functions including habitat provisioning, stream geomorphic stability, and water quality improvements; and as such, LW has increasingly been implemented in stream restoration activities. One of the proposed benefits to this restoration approach is that LW increases river-floodplain connectivity, potentially decreasing downstream flood peaks and improving water quality. Here, we conducted two experiential floods (i.e., one with and one without LW) in a headwater, agricultural stream to explore the effect of LW on river-floodplain connectivity and resulting hydrodynamic processes. During each flood, we released an equal amount of water to the stream channel, measured stream discharge at upstream and downstream boundaries, and measured inundation depth at multiple locations across the floodplain. We then utilized a 2-dimensional hydrodynamic model (HEC-RAS) to simulate floodplain hydrodynamics. We first calibrated the model using observations from the two experimental floods. Then, we utilized the calibrated model to evaluate differing LW placement strategies and effects under various flow conditions. Results show that the addition of LW to the channel decreased channel velocity and increased inundation extent, inundation depth, and floodplain velocity. Differential placement of LW along the stream impacted the levels of floodplain discharge, primarily due to the geomorphic characteristics of the stream. Finally, we examined the effects of LW on floodplain hydrodynamics across a synthetic flow record, and found that the magnitude of river-floodplain connectivity decreased as recurrence interval increased, with limited impacts on storm events with a recurrence interval of 25 years or greater. These findings suggest that LW plays a substantial role in river-floodplain connectivity of headwater streams and associated ecosystem services.

Chapter 1: Hydrologic exchange flows and their ecological consequences in river corridors

USGS Publications Warehouse

Harvey, Judson

2016-01-01

The actively flowing waters of streams and rivers remain in close contact with surrounding off-channel and subsurface environments. These hydrologic linkages between relatively fast flowing channel waters, with more slowly flowing waters off-channel and in the subsurface, are collectively referred to as hydrologic exchange flows (HEFs). HEFs include surface exchange with a channel’s marginal areas and subsurface flow through the streambed (hyporheic flow), as well as storm-driven bank storage and overbank flows onto floodplains. HEFs are important, not only for storing water and attenuating flood peaks, but also for their role in influencing water conservation, water quality improvement, and related outcomes for ecological values and services of aquatic ecosystems. Biogeochemical opportunities for chemical transformations are increased by HEFs as a result of the prolonged contact between flowing waters and geochemically and microbially active surfaces of sediments and vegetation. Chemical processing is intensified and water quality is often improved by removal of excess nutrients, metals, and organic contaminants from flowing waters. HEFs also are important regulators of organic matter decomposition, nutrient recycling, and stream metabolism that helps establish a balanced and resilient aquatic food web. The shallow and protected storage zones associated with HEFs support nursery and feeding areas for aquatic organisms that sustain aquatic biological diversity. Understanding of these varied roles for HEFs has been driven by the related disciplines of stream ecology, fluvial geomorphology, surface-water hydraulics, and groundwater hydrology. A current research emphasis is on the role that HEFs play in altered flow regimes, including restoration to achieve diverse goals, such as expanding aquatic habitats and managing dissolved and suspended river loads to reduce over-fertilization of coastal waters and offset wetland loss. New integrative concepts and models are emerging (eg, hydrologic connectivity) that emphasize HEF functions in river corridors over a wide range of spatial and temporal scales.

High frequency monitoring revels new insights into baseflow DOM processing

NASA Astrophysics Data System (ADS)

Khamis, K.; Bradley, C.; Blaen, P.; Krause, S.; Hannah, D. M.

2017-12-01

Dissolved organic matter (DOM) is important for myriad biogeochemical processes in river ecosystems. Currently, however, we have limited knowledge of DOM dynamics under low flow conditions as most previous studies have focused largely on storm event dynamics. Field deployable fluorescence technology offers new opportunities to explore diurnal DOM dynamics at finer time-steps and for longer periods than previously possible, thus providing new insights into in-stream DOM processing. In this study, we collected hourly fluorescence data (Spring - Fall) and a suite of hydro-climatological variables from two contrasting UK headwater watersheds: the urban Bourn Brook, Birmingham (52° 26' N, 1° 55' W) and agricultural Mill Haft, Shropshire (52° 48' N, 2° 14' W). We hypothesised that diurnal dynamics in humic-like fluorescence (Peak C; Ex. 365 nm / Em. 490 nm) would be driven by photo-oxidation processes; while tryptophan-like fluorescence (Peak T; Ex. 285 nm / Em. 345 nm) would respond to diurnal biomass production cycles. Wavelet analysis identified significant diurnal variations in Peak C for both the Bourn Brook and Mill Haft, with the strongest signal in early summer. While the amplitude was broadly similar between sites, peak timing and consistency differed, the Bourn Brook displayed peaks in the early morning (04:00 ± 2.2 h) and Mill Haft in early evening (19:00 ± 6.6 h). Cross wavelet analysis identified strong coherence with SW radiation for the urban stream but stronger relationships with discharge for the agricultural system. Hence, results from the Bourn Brook support our hypothesis regarding Peak C photo-oxidation processes but for Mill Haft, discharge (DOM dilution) appeared to be the key control. Contrary to our hypothesis, no strong diurnal pattern was identified for Peak T for either system. From this, we infer that the low levels of Peak T produced were rapidly taken up by bacteria and/or that productivity in these systems was low. Future work on in-stream DOM will benefit from improved integration of field deployable sensing and laboratory measurements.

Hawaii StreamStats; a web application for defining drainage-basin characteristics and estimating peak-streamflow statistics

USGS Publications Warehouse

Rosa, Sarah N.; Oki, Delwyn S.

2010-01-01

Reliable estimates of the magnitude and frequency of floods are necessary for the safe and efficient design of roads, bridges, water-conveyance structures, and flood-control projects and for the management of flood plains and flood-prone areas. StreamStats provides a simple, fast, and reproducible method to define drainage-basin characteristics and estimate the frequency and magnitude of peak discharges in Hawaii?s streams using recently developed regional regression equations. StreamStats allows the user to estimate the magnitude of floods for streams where data from stream-gaging stations do not exist. Existing estimates of the magnitude and frequency of peak discharges in Hawaii can be improved with continued operation of existing stream-gaging stations and installation of additional gaging stations for areas where limited stream-gaging data are available.

Ptaquiloside from bracken in stream water at base flow and during storm events.

PubMed

Clauson-Kaas, Frederik; Ramwell, Carmel; Hansen, Hans Chr B; Strobel, Bjarne W

2016-12-01

The bracken fern (Pteridium spp.) densely populates both open and woodland vegetation types around the globe. Bracken is toxic to livestock when consumed, and a group of potent illudane-type carcinogens have been identified, of which the compound ptaquiloside (PTA) is the most abundant. The highly water soluble PTA has been shown to be leachable from bracken fronds, and present in the soil and water below bracken stands. This has raised concerns over whether the compound might pose a risk to drinking water sources. We investigated PTA concentrations in a small stream draining a bracken-infested catchment at base flow and in response to storm events during a growth season, and included sampling of the bracken canopy throughfall. Streams in other bracken-dominated areas were also sampled at base flow for comparison, and a controlled pulse experiment was conducted in the field to study the in-stream dynamics of PTA. Ptaquiloside concentrations in the stream never exceeded 61 ng L -1 in the base flow samples, but peaked at 2.2 μg L -1 during the studied storm events. The mass of PTA in the stream, per storm event, was 7.5-93 mg from this catchment. A clear temporal connection was observed between rainfall and PTA concentration in the stream, with a reproducible time lag of approx. 1 h from onset of rain to elevated concentrations, and returning rather quickly (about 2 h) to base flow concentration levels. The concentration of PTA behaved similar to an inert tracer (Cl - ) in the pulse experiment over a relative short time scale (minutes-hours) reflecting no PTA sorption, and dispersion and dilution considerably lowered the observed PTA concentrations downstream. Bracken throughfall revealed a potent and lasting source of PTA during rainfall, with concentrations up to 169 μg L -1 , that did not decrease over the course of the event. In the stream, the throughfall contribution to PTA cannot be separated from a possible below-ground input from litter, rhizomes and soil. Catchment-specific factors such as the soil pH, topography, hydrology, and bracken coverage will evidently affect the level of PTA observed in the receiving stream, as well as the distance from bracken, but time since precipitation seems most important. Studying PTA loads and transport in surface streams fed by bracken-infested catchments, simply taking occasional grab samples will not capture the precipitation-linked pulses. The place and time of sampling governs the findings, and including event-based sampling is essential to provide a more complete picture of PTA loads to surface water. Copyright © 2016 Elsevier Ltd. All rights reserved.

Techniques for estimating flood peak discharges for unregulated streams and streams regulated by small floodwater retarding structures in Oklahoma

USGS Publications Warehouse

Tortorelli, R.L.; Bergman, D.L.

1985-01-01

Statewide regression relations for Oklahoma were determined for estimating peak discharge of floods for selected recurrence intervals from 2 to 500 years. The independent variables required for estimating flood discharge for rural streams are contributing drainage area and mean annual precipitation. Main-channel slope, a variable used in previous reports, was found to contribute very little to the accuracy of the relations and was not used. The regression equations are applicable for watersheds with drainage areas less than 2,500 square miles that are not significantly affected by regulation from manmade works. These relations are presented in graphical form for easy application. Limitations on the use of the regression relations and the reliability of regression estimates for rural unregulated streams are discussed. Basin and climatic characteristics, log-Pearson Type III statistics and the flood-frequency relations for 226 gaging stations in Oklahoma and adjacent states are presented. Regression relations are investigated for estimating flood magnitude and frequency for watersheds affected by regulation from small FRS (floodwater retarding structures) built by the U.S. Soil Conservation Service in their watershed protection and flood prevention program. Gaging-station data from nine FRS regulated sites in Oklahoma and one FRS regulated site in Kansas are used. For sites regulated by FRS, an adjustment of the statewide rural regression relations can be used to estimate flood magnitude and frequency. The statewide regression equations are used by substituting the drainage area below the FRS, or drainage area that represents the percent of the basin unregulated, in the contributing drainage area parameter to obtain flood-frequency estimates. Flood-frequency curves and flow-duration curves are presented for five gaged sites to illustrate the effects of FRS regulation on peak discharge.

Flood of July 12-13, 2004, Burlington and Camden Counties, South-Central New Jersey

USGS Publications Warehouse

Protz, Amy R.; Reed, Timothy J.

2006-01-01

Intense rainfall inundated south-central New Jersey on July 12-13, 2004, causing major flooding with heavy property, road, and bridge damage in Burlington and Camden Counties. Forty-five dams were topped or damaged, or failed completely. The affected areas were in the Rancocas Creek, Cooper River, and Pennsauken Creek Basins. The U.S. Geological Survey (USGS) documented peak stream elevations and flows at 56 selected sites within the affected area. With rainfall totals averaging more than 6 inches throughout the three basins, peak-of-record flood elevations and streamflows occurred at all but one USGS stream gage, where the previous record was tied. Flood-frequency recurrence-intervals ranged from 30 to greater than 100 years and maximum streamflow per square mile ranged from 13.9 to 263 cubic feet per second per square mile (ft3/s/mi2). Peak streamflow at USGS stream gages surrounding the affected basins are associated with considerably lower recurrence intervals and demonstrate the limited extent of the flood. A high tide of about 1 foot above monthly mean high tide did not contribute to high-water conditions. Low ground-water levels prior to the rainfall helped to mitigate flooding in the affected basins. Compared with historical floods in the Rancocas Creek Basin during 1938-40, the July 2004 flood had greater streamflow, but lower stream elevations. Property damage from the event was estimated at $50 million. Governor James E. McGreevy declared a State of Emergency in Burlington and Camden Counties on July 13, 2004. After assessment of the damage by the Federal Emergency Management Agency (FEMA), President George W. Bush declared Burlington and Camden Counties disaster areas on July 16, 2004.

Effects of Recent Debris Flows on Stream Ecosystems and Food Webs in Small Watersheds in the Central Klamath Mountains, NW California

NASA Astrophysics Data System (ADS)

Cover, M. R.; de La Fuente, J.

2008-12-01

Debris flows are common erosional processes in steep mountain areas throughout the world, but little is known about the long-term ecological effects of debris flows on stream ecosystems. Based on debris flow histories that were developed for each of ten tributary basins, we classified channels as having experienced recent (1997) or older (pre-1997) debris flows. Of the streams classified as older debris flow streams, three streams experienced debris flows during floods in 1964 or 1974, while two streams showed little or no evidence of debris flow activity in the 20th century. White alder (Alnus rhombifolia) was the dominant pioneer tree species in recent debris flow streams, forming localized dense patches of canopy cover. Maximum temperatures and daily temperature ranges were significantly higher in recent debris flow streams than in older debris flow streams. Debris flows resulted in a shift in food webs from allochthonous to autochthonous energy sources. Primary productivity, as measured by oxygen change during the day, was greater in recent debris flow streams, resulting in increased abundances of grazers such as the armored caddisfly Glossosoma spp. Detritivorous stoneflies were virtually absent in recent debris flow streams because of the lack of year-round, diverse sources of leaf litter. Rainbow trout (Oncorhynchus mykiss) were abundant in four of the recent debris flow streams. Poor recolonizers, such as the Pacific giant salamander (Dicamptodon tenebrosus), coastal tailed frog (Ascaphus truei), and signal crayfish (Pacifistacus leniusculus), were virtually absent in recent debris flow streams. Forest and watershed managers should consider the role of forest disturbances, such as road networks, on debris flow frequency and intensity, and the resulting ecological effects on stream ecosystems.

Flood-Frequency Estimates for Streams on Kaua`i, O`ahu, Moloka`i, Maui, and Hawai`i, State of Hawai`i

USGS Publications Warehouse

Oki, Delwyn S.; Rosa, Sarah N.; Yeung, Chiu W.

2010-01-01

This study provides an updated analysis of the magnitude and frequency of peak stream discharges in Hawai`i. Annual peak-discharge data collected by the U.S. Geological Survey during and before water year 2008 (ending September 30, 2008) at stream-gaging stations were analyzed. The existing generalized-skew value for the State of Hawai`i was retained, although three methods were used to evaluate whether an update was needed. Regional regression equations were developed for peak discharges with 2-, 5-, 10-, 25-, 50-, 100-, and 500-year recurrence intervals for unregulated streams (those for which peak discharges are not affected to a large extent by upstream reservoirs, dams, diversions, or other structures) in areas with less than 20 percent combined medium- and high-intensity development on Kaua`i, O`ahu, Moloka`i, Maui, and Hawai`i. The generalized-least-squares (GLS) regression equations relate peak stream discharge to quantified basin characteristics (for example, drainage-basin area and mean annual rainfall) that were determined using geographic information system (GIS) methods. Each of the islands of Kaua`i,O`ahu, Moloka`i, Maui, and Hawai`i was divided into two regions, generally corresponding to a wet region and a dry region. Unique peak-discharge regression equations were developed for each region. The regression equations developed for this study have standard errors of prediction ranging from 16 to 620 percent. Standard errors of prediction are greatest for regression equations developed for leeward Moloka`i and southern Hawai`i. In general, estimated 100-year peak discharges from this study are lower than those from previous studies, which may reflect the longer periods of record used in this study. Each regression equation is valid within the range of values of the explanatory variables used to develop the equation. The regression equations were developed using peak-discharge data from streams that are mainly unregulated, and they should not be used to estimate peak discharges in regulated streams. Use of a regression equation beyond its limits will produce peak-discharge estimates with unknown error and should therefore be avoided. Improved estimates of the magnitude and frequency of peak discharges in Hawai`i will require continued operation of existing stream-gaging stations and operation of additional gaging stations for areas such as Moloka`i and Hawai`i, where limited stream-gaging data are available.

Streamflow statistics for selected streams in North Dakota, Minnesota, Manitoba, and Saskatchewan

USGS Publications Warehouse

Williams-Sether, Tara

2012-01-01

Statistical summaries of streamflow data for the periods of record through water year 2009 for selected active and discontinued U.S. Geological Survey streamflow-gaging stations in North Dakota, Minnesota, Manitoba, and Saskatchewan were compiled. The summaries for each streamflow-gaging station include a brief station description, a graph of the annual peak and annual mean discharge for the period of record, statistics of monthly and annual mean discharges, monthly and annual flow durations, probability of occurrence of annual high discharges, annual peak discharge and corresponding gage height for the period of record, and monthly and annual mean discharges for the period of record.

Reconstructing the Santa Tecla flash flood in the Ondara River (Ebro Basin, NE Spain)

NASA Astrophysics Data System (ADS)

Balasch, J. C.; Tuset, J.; Ramos, M. C.; Martínez-Casasnovas, J. A.

2009-09-01

The Santa Tecla flood may be considered the most catastrophic rainfall event in the modern history of Catalonia (NE Iberian Peninsula), and one of the most important in the Western Mediterranean Basin. This event took place during the night between 22nd and 23rd September 1874, in which torrential convective rainfalls generated significant flash floods in most of the small streams in the southern half of Catalonia (i.e. Ondara, Corb, Francolí and Siurana catchments). More than 570 people died, 150 of which in the town of Tàrrega, by the Ondara River. Despite being one of the last huge floods of the pre-instrumental era and, consequently, without any precipitation or flow data, the event was reconstructed both hydraulically and hydrologically for the Ondara River at Tàrrega (150 km2). Thus, the maximum water level and the temporal evolution of the flood were obtained, respectively, from several epigraphic limnimarks found in Tàrrega and from the event description recorded in historical documents. Additionally, the information from local archaeological sites allowed the reconstruction of the fluvial section at Tàrrega at the end of the 19th century. Finally, some old cellars flooded during the event provided information about sediment concentration at the peak flow. The methodology put into practice for the event reconstruction had two stages. The first stage was the hydraulic modelling, which estimated the peak flow. The input data used were the maximum water level given by the limnimetric marks, a digital terrain model of the river bed shape, and the stream and floodplain roughness and channel slope (which were considered similar to the present ones, according to archaeological data). The hydraulic model used was the unidimensional HEC-RAS (USACE), applied in several cross sections of the Ondara River at Tàrrega. The second stage was the hydrological modelling. The objective of this stage was to derive the event hyetograph from the above calculated peak flow and the hydrologic response of the basin. This hydrologic behaviour, that is the relation between the hyetograph and the hydrograph, was estimated taking into account rainfall duration (6-8 hours according to historical documents), basin characteristics, soil type, soil land use and cover and the antecedent soil moisture, using SCS Curve Number method. After that, a transfer Synthetic Unitary Hydrograph function and a wave propagation method (Muskingum) were applied to describe the discharge evolution and the water routing into the stream channel. The software used in this stage was the HEC-HMS (USACE). The results of the hydraulic simulation at the Sant Agustí street cross section were the following: a) a maximum water depth of 6.16 m above the original river bed, b) a mean water velocity of about 2 m•s-1, c) a peak flow of 996 m3•s-1 (increased by 480 m3•s-1 from the Cercavins River downstream Tàrrega), and d) a specific peak discharge of the event of 6.6 m3•s-1•km-2, which exceeds the values of the 500-year return period floods compiled from the Ebro drainage basin systematic database. From the information obtained in the flooded cellars, the sediment concentration during the peak flow was estimated in 11.2% (in volume), characteristic of a hyperconcentrated flow. The water level reached in the abovepresented cross section is partly explained by the recently discovered Sant Agustí Bridge, buried until now in the river bed. The results of the hydrologic modelling were: a) a surface runoff total volume of 12 hm3, b) a runoff coefficient of about 35.5%, c) a lagtime of 2.5-3 hours, and d) if the previous soil humidity for the Curve Number method was low (situation I), a total rainfall of 225 mm with a peak intensity higher than 100 mm•h-1 is needed; if the previous soil humidity for the Curve Number method was medium (situation II), a total rainfall of 156 mm with a peak intensity of about 70 mm•h-1 occurs. Rainfall values for medium previous moisture condition (II) represent a 1000-year return period according to the regional systematic data.

Projected Impact of Climate Change on Hydrological Regimes in the Philippines

PubMed Central

Kanamaru, Hideki; Keesstra, Saskia; Maroulis, Jerry; David, Carlos Primo C.; Ritsema, Coen J.

2016-01-01

The Philippines is one of the most vulnerable countries in the world to the potential impacts of climate change. To fully understand these potential impacts, especially on future hydrological regimes and water resources (2010-2050), 24 river basins located in the major agricultural provinces throughout the Philippines were assessed. Calibrated using existing historical interpolated climate data, the STREAM model was used to assess future river flows derived from three global climate models (BCM2, CNCM3 and MPEH5) under two plausible scenarios (A1B and A2) and then compared with baseline scenarios (20th century). Results predict a general increase in water availability for most parts of the country. For the A1B scenario, CNCM3 and MPEH5 models predict an overall increase in river flows and river flow variability for most basins, with higher flow magnitudes and flow variability, while an increase in peak flow return periods is predicted for the middle and southern parts of the country during the wet season. However, in the north, the prognosis is for an increase in peak flow return periods for both wet and dry seasons. These findings suggest a general increase in water availability for agriculture, however, there is also the increased threat of flooding and enhanced soil erosion throughout the country. PMID:27749908

Controls on old and new water contributions to stream flow at some nested catchments in Vermont, USA

USGS Publications Warehouse

Shanley, J.B.; Kendall, C.; Smith, T.E.; Wolock, D.M.; McDonnell, Jeffery J.

2002-01-01

Factors controlling the partitioning of old and new water contributions to stream flow were investigated for three events in four catchments (three of which were nested) at Sleepers River Research Watershed in Danville, Vermont. In the 1993 snowmelt period, two-component isotopic hydrograph separations showed that new water (meltwater) inputs to the stream ranged widely from 41 to 74%, and increased with catchment size (41 to 11 125 ha) (with one exception) and with open land cover (0-73%). Peak dissolved organic carbon concentrations and relative alkalinity dilution in stream water ranked in the same order among catchments as the new water fractions, suggesting that new water followed shallow flow paths. During the 1994 snowmelt, despite similar timing and magnitude of melt inputs, the new-water contribution to stream flow ranged only from 30 to 36% in the four catchments. We conclude that the uncommonly high and variable new water fractions in streamwater during the 1993 melt were caused by direct runoff of meltwater over frozen ground, which was prevalent in open land areas during the 1993 winter. In a high-intensity summer rainstorm in 1993, new water fractions were smaller relative to the 1993 snowmelt, ranging from 28 to 46%, but they ranked in the identical catchment order. Reconciliation of the contrasting patterns of new-old water partitioning in the three events appears to require an explanation that invokes multiple processes and effects, including: 1 topographically controlled increase in surface-saturated area with increasing catchment size; 2 direct runoff over frozen ground; 3 low infiltration in agriculturally compacted soils; 4 differences in soil transmissivity, which may be more relevant under dry antecedent conditions. These data highlight some of the difficulties faced by catchment hydrologists in formulating a theory of runoff generation at varying basin scales. Copyright ?? 2002 John Wiley and Sons, Ltd.

Controls on old and new water contributions to stream flow at some nested catchments in Vermont, USA

NASA Astrophysics Data System (ADS)

Shanley, James B.; Kendall, Carol; Smith, Thor E.; Wolock, David M.; McDonnell, Jeffrey J.

2002-02-01

Factors controlling the partitioning of old and new water contributions to stream flow were investigated for three events in four catchments (three of which were nested) at Sleepers River Research Watershed in Danville, Vermont. In the 1993 snowmelt period, two-component isotopic hydrograph separations showed that new water (meltwater) inputs to the stream ranged widely from 41 to 74%, and increased with catchment size (41 to 11 125 ha) (with one exception) and with open land cover (0-73%). Peak dissolved organic carbon concentrations and relative alkalinity dilution in stream water ranked in the same order among catchments as the new water fractions, suggesting that new water followed shallow flow paths. During the 1994 snowmelt, despite similar timing and magnitude of melt inputs, the new-water contribution to stream flow ranged only from 30 to 36% in the four catchments. We conclude that the uncommonly high and variable new water fractions in streamwater during the 1993 melt were caused by direct runoff of meltwater over frozen ground, which was prevalent in open land areas during the 1993 winter. In a high-intensity summer rainstorm in 1993, new water fractions were smaller relative to the 1993 snowmelt, ranging from 28 to 46%, but they ranked in the identical catchment order. Reconciliation of the contrasting patterns of new-old water partitioning in the three events appears to require an explanation that invokes multiple processes and effects, including: 1.topographically controlled increase in surface-saturated area with increasing catchment size;2.direct runoff over frozen ground;3.low infiltration in agriculturally compacted soils;4.differences in soil transmissivity, which may be more relevant under dry antecedent conditions. These data highlight some of the difficulties faced by catchment hydrologists in formulating a theory of runoff generation at varying basin scales.

Montana StreamStats—A method for retrieving basin and streamflow characteristics in Montana: Chapter A in Montana StreamStats

USGS Publications Warehouse

McCarthy, Peter M.; Dutton, DeAnn M.; Sando, Steven K.; Sando, Roy

2016-04-05

The U.S. Geological Survey (USGS) provides streamflow characteristics and other related information needed by water-resource managers to protect people and property from floods, plan and manage water-resource activities, and protect water quality. Streamflow characteristics provided by the USGS, such as peak-flow and low-flow frequencies for streamflow-gaging stations, are frequently used by engineers, flood forecasters, land managers, biologists, and others to guide their everyday decisions. In addition to providing streamflow characteristics at streamflow-gaging stations, the USGS also develops regional regression equations and drainage area-adjustment methods for estimating streamflow characteristics at locations on ungaged streams. Regional regression equations can be complex and often require users to determine several basin characteristics, which are physical and climatic characteristics of the stream and its drainage basin. Obtaining these basin characteristics for streamflow-gaging stations and ungaged sites traditionally has been time consuming and subjective, and led to inconsistent results.StreamStats is a Web-based geographic information system application that was created by the USGS to provide users with access to an assortment of analytical tools that are useful for water-resource planning and management. StreamStats allows users to easily obtain streamflow and basin characteristics for USGS streamflow-gaging stations and user-selected locations on ungaged streams. The USGS, in cooperation with Montana Department of Transportation, Montana Department of Environmental Quality, and Montana Department of Natural Resources and Conservation, completed a study to develop a StreamStats application for Montana, compute streamflow characteristics at streamflow-gaging stations, and develop regional regression equations to estimate streamflow characteristics at ungaged sites. Chapter A of this Scientific Investigations Report describes the Montana StreamStats application and the datasets, streamflow-gaging stations, streamflow characteristics, and regression equations (as described fully in Chapters B through G of this report) that are used for development of the StreamStats application for Montana.

Effects of suburban development on runoff generation in the Croton River basin, New York, USA

USGS Publications Warehouse

Burns, D.; Vitvar, T.; McDonnell, J.; Hassett, J.; Duncan, J.; Kendall, C.

2005-01-01

The effects of impervious area, septic leach-field effluent, and a riparian wetland on runoff generation were studied in three small (0.38-0.56 km 2) headwater catchments that represent a range of suburban development (high density residential, medium density residential, and undeveloped) within the Croton River basin, 70 km north of New York City. Precipitation, stream discharge, and groundwater levels were monitored at 10-30 min intervals for 1 year, and stream water and groundwater samples were collected biweekly for ??18O, NO3-, and SO42- analysis for more than 2 years during an overlapping period in 2000-2002. Data from 27 storms confirmed that peak magnitudes increased and recession time decreased with increasing development, but lags in peak arrival and peak discharge/mean discharge were greatest in the medium density residential catchment, which contains a wetland in which storm runoff is retained before entering the stream. Baseflow during a dry period from Aug. 2001-Feb. 2002 was greatest in the high-density residential catchment, presumably from the discharge of septic effluent through the shallow groundwater system and into the stream. In contrast, moderate flows during a wet period from Mar.-Aug. 2002 were greatest in the undeveloped catchment, possibly as a result of greater subsurface storage or greater hydraulic conductivity at this site. The mean residence time of baseflow was about 30 weeks at all three catchments, indicating that human influence was insufficient to greatly affect the groundwater recharge and discharge properties that determine catchment residence time. These results suggest that while suburban development and its associated impervious surfaces and storm drains accelerate the transport of storm runoff into streams, the combined effects of remnant natural landscape features such as wetlands and human alterations such as deep groundwater supply and septic systems can change the expected effects of human development on storm runoff and groundwater recharge. ?? 2005 Elsevier B.V. All rights reserved.

Temporal variation in phenotypic and genotypic traits in two sockeye salmon populations, Tustumena Lake, Alaska

USGS Publications Warehouse

Woody, Carol Ann; Olsen, Jeffrey B.; Reynolds, Joel H.; Bentzen, Paul

2000-01-01

Sockeye salmon Oncorhynchus nerka in two tributary streams (about 20 km apart) of the same lake were compared for temporal variation in phenotypic (length, depth adjusted for length) and genotypic (six microsatellite loci) traits. Peak run time (July 16 versus 11 August) and run duration (43 versus 26 d) differed between streams. Populations were sampled twice, including an overlapping point in time. Divergence at microsatellite loci followed a temporal cline: Population sample groups collected at the same time were not different (F ST = 0), whereas those most separated in time were different (F ST = 0.011, P = 0.001). Although contemporaneous sample groups did not differ significantly in microsatellite genotypes (F ST = 0), phenotypic traits did differ significantly (MANOVA, P < 0.001). Fish from the larger stream were larger; fish from the smaller stream were smaller, suggesting differential fitness related to size. Results indicate run time differences among and within sockeye salmon populations may strongly influence levels of gene flow.

Cottonwood Tree Rings and Climate in Western North America

NASA Astrophysics Data System (ADS)

Friedman, J. M.; Edmondson, J.; Griffin, E. R.; Meko, D. M.; Merigliano, M. F.; Scott, J. A.; Scott, M. L.; Touchan, R.

2012-12-01

In dry landscapes of interior western USA, cottonwood (Populus spp.) seedling establishment often occurs only close to river channels after floods. Where winter is sufficiently cold, cottonwoods also have distinct annual rings and can live up to 370 years, allowing us to reconstruct the long-term history of river flows and channel locations. We have analyzed the annual rate of cottonwood establishment along streams in Montana, Wyoming, Colorado, North Dakota and Idaho. Because the trees germinate next to the river, establishment rates are strongly correlated with the rate of channel migration driven by floods. Along large rivers dominated by snowmelt from the mountains, interannual variation in peak flows and cottonwood establishment is small, and century-scale variation driven by climate change is apparent. The upper Snake, Yellowstone and Green rivers all show a strong decrease in cottonwood establishment beginning in the late 1800s and continuing to the present, indicating a decrease in peak flows prior to flow regulation by large dams. This is consistent with published tree-ring studies of montane conifers showing decreases in snowpack at the same time scale. In contrast, beginning in the late 1800s cottonwood ring widths along the Little Missouri River, North Dakota show an increase in annual growth that continues into the present. Because annual growth is strongly correlated with April-July flows (r=0.69) the ring-width data suggest an increase in April-July flows at the same time tree establishment dates suggest a decrease in peak flows. These results may be reconciled by the hypothesis that increases in low temperatures have decreased snowpack while lengthening the growing season.

Upland and in-stream controls on baseflow nutrient dynamics in tile-drained agroecosystem watersheds

NASA Astrophysics Data System (ADS)

Ford, William I.; King, Kevin; Williams, Mark R.

2018-01-01

In landscapes with low residence times (e.g., rivers and reservoirs), baseflow nutrient concentration dynamics during sensitive timeframes can contribute to deleterious environmental conditions downstream. This study assessed upland and in-stream controls on baseflow nutrient concentrations in a low-gradient, tile-drained agroecosystem watershed. We conducted time-series analysis using Empirical mode decomposition of seven decade-long nutrient concentration time-series in the agricultural Upper Big Walnut Creek watershed (Ohio, USA). Four tributaries of varying drainage areas and three main-stem sites were monitored, and nutrient grab samples were collected weekly from 2006 to 2016 and analyzed for dissolved reactive phosphorus (DRP), nitrate-nitrogen (NO3-N), total nitrogen (TN), and total phosphorus (TP). Statistically significant seasonal fluctuations were compared with seasonality of baseflow, watershed characteristics (e.g., tile-drain density), and in-stream water quality parameters (pH, DO, temperature). Findings point to statistically significant seasonality of all parameters with peak P concentrations in summer and peak N in late winter-early spring. Results suggest that upland processes exert strong control on DRP concentrations in the winter and spring months, while coupled upland and in-stream conditions control watershed baseflow DRP concentrations during summer and early fall. Conversely, upland flow sources driving streamflow exert strong control on baseflow NO3-N, and in-stream attenuation through transient and permanent pathways impacts the magnitude of removal. Regarding TN and TP, we found that TN was governed by NO3-N, while TP was governed by DRP in summer and fluvial erosion of P-rich benthic sediments during higher baseflow conditions. Findings of the study highlight the importance of coupled in-stream and upland management for mitigating eutrophic conditions during environmentally sensitive timeframes.

Techniques for simulating flood hydrographs and estimating flood volumes for ungaged basins in east and west Tennessee

USGS Publications Warehouse

Gamble, C.R.

1989-01-01

A dimensionless hydrograph developed for a variety of basin conditions in Georgia was tested for its applicability to streams in East and West Tennessee by comparing it to a similar dimensionless hydrograph developed for streams in East and West Tennessee. Hydrographs of observed discharge at 83 streams in East Tennessee and 38 in West Tennessee were used in the study. Statistical analyses were performed by comparing simulated (or computed) hydrographs, derived by application of the Georgia dimensionless hydrograph, and dimensionless hydrographs developed from Tennessee data, with the observed hydrographs at 50 and 75% of their peak-flow widths. Results of the tests indicate that the Georgia dimensionless hydrography is virtually the same as the one developed for streams in East Tennessee, but that it is different from the dimensionless hydrograph developed for streams in West Tennessee. Because of the extensive testing of the Georgia dimensionless hydrograph, it was determined to be applicable for East Tennessee, whereas the dimensionless hydrograph developed from data on streams in West Tennessee was determined to be applicable in West Tennessee. As part of the dimensionless hydrograph development, an average lagtime in hours for each study basin, and the volume in inches of flood runoff for each flood event were computed. By use of multiple-regression analysis, equations were developed that relate basin lagtime to drainage area size, basin length, and percent impervious area. Similarly, flood volumes were related to drainage area size, peak discharge, and basin lagtime. These equations, along with the appropriate dimensionless hydrograph, can be used to estimate a typical (average) flood hydrograph and volume for recurrence-intervals up to 100 years at any ungaged site draining less than 50 sq mi in East and West Tennessee. (USGS)

The effects of drainage basin geomorphometry on minimum low flow discharge: the study of small watershed in Kelang River Valley in Peninsular Malaysia.

PubMed

Yunus, Ahmad Jailani Muhamed; Nakagoshi, Nobukazu; Salleh, Khairulmaini Osman

2003-03-01

This study investigate the relationships between geomorphometric properties and the minimum low flow discharge of undisturbed drainage basins in the Taman Bukit Cahaya Seri Alam Forest Reserve, Peninsular Malaysia. The drainage basins selected were third-order basins so as to facilitate a common base for sampling and performing an unbiased statistical analyses. Three levels of relationships were observed in the study. Significant relationships existed between the geomorphometric properties as shown by the correlation network analysis; secondly, individual geomorphometric properties were observed to influence minimum flow discharge; and finally, the multiple regression model set up showed that minimum flow discharge (Q min) was dependent of basin area (AU), stream length (LS), maximum relief (Hmax), average relief (HAV) and stream frequency (SF). These findings further enforced other studies of this nature that drainage basins were dynamic and functional entities whose operations were governed by complex interrelationships occurring within the basins. Changes to any of the geomorphometric properties would influence their role as basin regulators thus influencing a change in basin response. In the case of the basin's minimum low flow, a change in any of the properties considered in the regression model influenced the "time to peak" of flow. A shorter time period would mean higher discharge, which is generally considered the prerequisite to flooding. This research also conclude that the role of geomorphometric properties to control the water supply within the stream through out the year even though during the drought and less precipitations months. Drainage basins are sensitive entities and any deteriorations involve will generate reciprocals and response to the water supply as well as the habitat within the areas.

Simulation of flood hydrographs for Georgia streams

USGS Publications Warehouse

Inman, Ernest J.

1987-01-01

Flood hydrographs are needed for the design of many highway drainage structures and embankments. A method for simulating these flood hydrographs at ungaged sites in Georgia is presented in this report. The O'Donnell method was used to compute unit hydrographs and lagtimes for 355 floods at 80 gaging stations. An average unit hydrograph and an average lagtime were computed for each station. These average unit hydrographs were transformed to unit hydrographs having durations of one-fourth, one-third, one-half, and three-fourths lagtime, then reduced to dimensionless terms by dividing the time by lagtime and the discharge by peak discharge. Hydrographs were simulated for these 355 floods and their widths were compared with the widths of the observed hydrographs at 50 and 75 percent of peak flow. The dimensionless hydrograph based on one-half lagtime duration provided the best fit of the observed data. Multiple regression analysis was then used to define relations between lagtime and certain physical basin characteristics; of these characteristics, drainage area and slope were found to be significant for the rural-stream equations and drainage area, slope, and impervious area were found to be significant for the Atlanta urban-stream equation. A hydrograph can be simulated from the dimensionless hydrograph, the peak discharge of a specific recurrence interval, and the lagtime obtained from regression equations for any site in Georgia having a drainage area of less than 500 square miles. For simulating hydrographs at sites having basins larger than 500 square miles, the U.S. Geological Survey computer model CONROUT can be used. This model routes streamflow from an upstream channel location to a user-defined location downstream. The product of CONROUT is a simulated discharge hydrograph for the downstream site that has a peak discharge of a specific recurrence interval.

General field and office procedures for indirect discharge measurements

USGS Publications Warehouse

Benson, M.A.; Dalrymple, Tate

2001-04-01

The discharge of streams is usually measured by the current-meter method. During flood periods, however, it is frequently impossible or impractical to measure the discharges by this method when they occur. Consequently, many peak discharges must be determined after the passage of the flood by indirect methods, such as slope-area, contracted-opening, flow-over-dam, and flow-through-culvert, rather than by direct current-meter measurement. Indirect methods of determining peak discharge are based on hydraulic equations which relate the discharge to the water-surface profile and the geometry of the channel. A field survey is made after the flood to determine the location and elevation of high-water marks and the characteristics of the channel. Detailed descriptions of the general procedures used in collecting the field data and in computing the discharge are given in this report. Each of the methods requires special procedures described in subsequent chapters.

Peak-flow frequency estimates based on data through water year 2001 for selected streamflow-gaging stations in South Dakota

USGS Publications Warehouse

Sando, Steven K.; Driscoll, Daniel G.; Parrett, Charles

2008-01-01

Numerous users, including the South Dakota Department of Transportation, have continuing needs for peak-flow information for the design of highway infrastructure and many other purposes. This report documents results from a cooperative study between the South Dakota Department of Transportation and the U.S. Geological Survey to provide an update of peak-flow frequency estimates for South Dakota. Estimates of peak-flow magnitudes for 2-, 5-, 10-, 25-, 50-, 100-, 200-, and 500-year recurrence intervals are reported for 272 streamflow-gaging stations, which include most gaging stations in South Dakota with 10 or more years of systematic peak-flow records through water year 2001. Recommended procedures described in Bulletin 17B were used as primary guidelines for developing peak-flow frequency estimates. The computer program PEAKFQ developed by the U.S. Geological Survey was used to run the frequency analyses. Flood frequencies for all stations were initially analyzed by using standard Bulletin 17B default procedures for fitting the log-Pearson III distribution. The resulting preliminary frequency curves were then plotted on a log-probability scale, and fits of the curves with systematic data were evaluated. In many cases, results of the default Bulletin 17B analyses were determined to be satisfactory. In other cases, however, the results could be improved by using various alternative procedures for frequency analysis. Alternative procedures for some stations included adjustments to skew coefficients or use of user-defined low-outlier criteria. Peak-flow records for many gaging stations are strongly influenced by low- or zero-flow values. This situation often results in a frequency curve that plots substantially above the systematic record data points at the upper end of the frequency curve. Adjustments to low-outlier criteria reduced the influence of very small peak flows and generally focused the analyses on the upper parts of the frequency curves (10- to 500-year recurrence intervals). The most common alternative procedures involved several different methods to extend systematic records, which was done primarily to address biases resulting from nonrepresentative climatic conditions during several specific periods of record and to reduce inconsistencies among multiple gaging stations along common stream channels with different periods of record. In some cases, records for proximal stations could be combined directly. In other cases, the two-station comparison procedure recommended in Bulletin 17B was used to adjust the mean and standard deviation of the logs of the systematic data for a target station on the basis of correlation with concurrent records from a nearby long-term index station. In some other cases, a 'mixed-station procedure' was used to adjust the log-distributional parameters for a target station, on the basis of correlation with one or more index stations, for the purpose of fitting the log-Pearson III distribution. Historical adjustment procedures were applied to peak-flow frequency analyses for 17 South Dakota gaging stations. A historical adjustment period extending back to 1881 (121 years) was used for 12 gaging stations in the James and Big Sioux River Basins, and various other adjustment periods were used for additional stations. Large peak flows that occurred in 1969 and 1997 accounted for 13 of the 17 historical adjustments. Other years for which historical peak flows were used include 1957, 1962, 1992, and 2001. A regional mixed-population analysis was developed to address complications associated with many high outliers for the Black Hills region. This analysis included definition of two populations of flood events. The population of flood events that composes the main body of peak flows for a given station is considered the 'ordinary-peaks population,' and the population of unusually large peak flows that plot substantially above the main body of peak flows on log-probability scale is co

Hydrology and Water Quality of the Rio Chama River, Northern New Mexico: Establishing a Base Line to Manage Flows

NASA Astrophysics Data System (ADS)

Salvato, L.; Crossey, L. J.

2013-12-01

The Rio Chama is the largest stream tributary to the Rio Grande in northern New Mexico. The river's geographic location in a semiarid region results in high rates of evapotranspiration and highly variable streamflow. The Rio Chama is part of the San Juan-Chama Drinking Water Project, in which water from the San Juan River, southern Colorado, is diverted across the continental divide to the Rio Chama. Surface water moves through Abiquiu, El Vado and Heron Reservoirs to the Rio Grande to supply Albuquerque with potable drinking water. The results of these anthropogenic influences are a modified flow regime, less variability, greater base-flows, and smaller peak flows. We examined selected locations throughout the Rio Chama system to provide base-line water quality data for ongoing studies. This information will contribute to the development of the best plan to optimize flow releases and maximize benefits of the stakeholders and especially the riparian and stream ecosystems. We report results of two sampling trips representing extremes of the hydrograph in summer 2012 and fall 2012. We collected field parameters, processed water samples, and analyzed them for major anions and cations. The geochemistry enables us to better understand the impact of monthly releases of San Juan river water. We captured two points of the river's streamflow range, 54 cubic feet per second in October 2012 and 1,000 cubic feet per second in August 2012 and looked for variability within the results. We found that the reservoirs exhibit varying anion concentrations from samples taken at different depths. We compared stream waters and selected well samples at a stream transect. These samples allowed us to compare shallow ground water with the stream, and they indicated that the changes in ground water are attributed to sulfate reduction. The anion and cation inputs were most likely derived from gypsum, calcite, and salts, as there are many creeks discharging into the Rio Chama whose drainage basins contain exposures of strata bearing these minerals. We established base-line information at the extremes of flow, and our future work will integrate repeat sampling with water level data to more robustly correlate water quality characteristics with release flows. Rio Chama River, Northern New Mexico

Pattern of solute movement from snow into an upper Michigan stream

USGS Publications Warehouse

Stottlemyer, R.; Toczydlowski, D.

1990-01-01

Precipitation, snowpack, snowmelt, and streamwater samples were collected in a small gauged watershed draining into Lake Superior during winter 1987–88 to assess the importance of snowmelt pattern and meltwater pathways in the occurrence of solute pulses in streamwater. The snowpack along the south shore of Lake Superior can contain 50% of annual precipitation inputs and 38% of annual ionic inputs including moderate levels of strong acids. Throughout winter, thawed surface soils and small but steady snowpack moisture release promoted movement of snowpack solutes to surface mineral soils. Preferential elution of K+, NH4+, and H+ from the snowpack occurred with the initial thaw. Most ions exhibited pulses in snowmelt. Transport of snowpack solutes to the stream during snowmelt was through near-surface soil macropores and overland flow. For those ions with concentrations higher in the snowpack than in the premelt streamwater, K+, NH4+, and H+, the earliest snowmelt pulses had the greatest influence on streamwater chemistry. Unlike other portions of the region with resistant bedrock, the widespread presence of alkaline glacial till provides excess stream acid neutralization capacity (ANC) to buffer acidic inputs. Peak winter streamwater ANC reduction was caused principally by spring melt dilution of base cations and associated alkalinity, constant high SO42- levels, and an increase in NO3-. The maximum reduction in stream ANC was concurrent with overland flow. Relative to its snowmelt concentration, NO3- was highest in streamwater with some stream input likely the result of nitrification and N mineralization.

Hydrology and water quality of the copper-nickel study region, northeastern Minnesota

USGS Publications Warehouse

Siegel, Donald I.; Ericson, Donald W.

1980-01-01

Data were collected on the hydrology of the Copper-Nickel study region to identify the location and nature of groundwater resources, determine the flow characteristics and general quality of the major streams, and determine the potential effects of mining copper and nickel on the hydrologic stream. Groundwater generally occurs in local flow systems within surficial deposits and in fractures in the upper few hundred feet of bedrock. Yields commonly range from 1 to 5 gallons per minute from wells in surficial materials and bedrock, but can be as much as 1,000 gallons per minute from wells in the sand and gravel aquifer underlying the Embarrass River valley. Groundwater generally is calcium-magnesium bicarbonate types. Over a mineralized zone, groundwater has concentrations of copper and nickel greater than 5 micrograms per liter. The average annual runoff from streams in the study area is about 10 inches. About 60% of the annual runoff occurs during snowmelt in spring. Flood peaks are reduced in streams that have surface storage available in on-channel lakes and wetlands. Specific conductance in streams can exceed 250 micromhos per centimeter at 25 Celsius where mine dewatering supplements natural discharge. Estimated groundwater discharge to projected copper-nickel mines ranges from less than 25 to about 2,000 gallons per minute. The introduction of trace metals from future mining activities to the groundwater system can be reduced if tailings basins and stockpiles are located on material which has low permeability, such as till, peat, or bedrock. (USGS)

Magnitude, frequency, and trends of floods at gaged and ungaged sites in Washington, based on data through water year 2014

USGS Publications Warehouse

Mastin, Mark C.; Konrad, Christopher P.; Veilleux, Andrea G.; Tecca, Alison E.

2016-09-20

An investigation into the magnitude and frequency of floods in Washington State computed the annual exceedance probability (AEP) statistics for 648 U.S. Geological Survey unregulated streamgages in and near the borders of Washington using the recorded annual peak flows through water year 2014. This is an updated report from a previous report published in 1998 that used annual peak flows through the water year 1996. New in this report, a regional skew coefficient was developed for the Pacific Northwest region that includes areas in Oregon, Washington, Idaho and western Montana within the Columbia River drainage basin south of the United States-Canada border, the coastal areas of Oregon and western Washington, and watersheds draining into Puget Sound, Washington. The skew coefficient is an important term in the Log Pearson Type III equation used to define the distribution of the log-transformed annual peaks. The Expected Moments Algorithm was used to fit historical and censored peak-flow data to the log Pearson Type III distribution. A Multiple Grubb-Beck test was employed to censor low outliers of annual peak flows to improve on the frequency distribution. This investigation also includes a section on observed trends in annual peak flows that showed significant trends (p-value < 0.05) in 21 of 83 long-term sites, but with small magnitude Kendall tau values suggesting a limited monotonic trend in the time series of annual peaks. Most of the sites with a significant trend in western Washington were positive and all the sites with significant trends (three sites) in eastern Washington were negative.Multivariate regression analysis with measured basin characteristics and the AEP statistics at long-term, unregulated, and un-urbanized (defined as drainage basins with less than 5 percent impervious land cover for this investigation) streamgages within Washington and some in Idaho and Oregon that are near the Washington border was used to develop equations to estimate AEP statistics at ungaged basins. Washington was divided into four regions to improve the accuracy of the regression equations; a set of equations for eight selected AEPs and for each region were constructed. Selected AEP statistics included the annual peak flows that equaled or exceeded 50, 20, 10, 4, 2, 1, 0.5 and 0.2 percent of the time equivalent to peak flows for peaks with a 2-, 5-, 10-, 25-, 50-, 100-, 200-, and 500-year recurrence intervals, respectively. Annual precipitation and drainage area were the significant basin characteristics in the regression equations for all four regression regions in Washington and forest cover was significant for the two regression regions in eastern Washington. Average standard error of prediction for the regional regression equations ranged from 70.19 to 125.72 percent for Regression Regions 1 and 2 on the eastern side of the Cascade Mountains and from 43.22 to 58.04 percent for Regression Regions 3 and 4 on the western side of the Cascade Mountains. The pseudo coefficient of determination (where a value of 100 signifies a perfect regression model) ranged from 68.39 to 90.68 for Regression Regions 1 and 2, and 92.35 to 95.44 for Regions 3 and 4.The calculated AEP statistics for the streamgages and the regional regression equations are expected to be incorporated into StreamStats after the publication of this report. StreamStats is the interactive Web-based map tool created by the U.S. Geological Survey to allow the user to choose a streamgage and obtain published statistics or choose ungaged locations where the program automatically applies the regional regression equations and computes the estimates of the AEP statistics.

Multi-stream portrait of the Cosmic web

NASA Astrophysics Data System (ADS)

Ramachandra, Nesar; Shandarin, Sergei

2016-03-01

We report the results of the first study of the multi-stream environment of dark matter haloes in cosmological N-body simulations in the ΛCDM cosmology. The full dynamical state of dark matter can be described as a three-dimensional sub-manifold in six-dimensional phase space - the dark matter sheet. In our study we use a Lagrangian sub-manifold x = x (q , t) (where x and q are co-moving Eulerian and Lagrangian coordinates respectively), which is dynamically equivalent to the dark matter sheet but is more convenient for numerical analysis. Our major results can be summarized as follows. At the resolution of the simulation, the cosmic web represents a hierarchical structure: each halo is embedded in the filamentary framework of the web predominantly at the filament crossings, and each filament is embedded in the wall like fabric of the web at the wall crossings. Locally, each halo or sub-halo is a peak in the number of streams field. The number of streams in the neighbouring filaments is higher than in the neighbouring walls. The walls are regions where number of streams is equal to three or a few. Voids are uniquely defined by the local condition requiring to be a single-stream flow region.

A Case Study of Differing Effects of Urbanization on Streamflow From Two Proximate Watersheds

NASA Astrophysics Data System (ADS)

Brandes, D.; Lott, F.

2007-12-01

The effects of urbanization on streamflow from two proximate watersheds (Little Lehigh Creek (LLC) and Monocacy Creek (MC)) are investigated. Despite close similarities in rainfall, population growth, land use, imperviousness, and geology of the watersheds, streamflows at the LLC gage have changed markedly over the past 50 years, while those at the MC gage have not. In LLC, there are significant increasing trends in annual stormflow volume, annual maximum flow, and flashiness, but there are no significant trends in these measures in MC. Neither stream shows significant trends in annual baseflow volume or low flow. It appears that the distinct difference in response to urbanization of these two streams can be ascribed to differences in 1) watershed geomorphology, 2) spatial distribution, composition, and infiltration characteristics of carbonate bedrock, and 3) the spatial pattern of land development in each watershed with respect to the gage location. In regards to geomorphology, there is a steeper main channel and narrower floodplains in LLC than in MC. Carbonate soil and bedrock (primarily dolostone) are distributed throughout much of LLC watershed but only in the lower half of MC watershed; however the lower MC watershed (primarily limestone) has much more abundant sinkholes and karst features than in the LLC watershed. Finally, residential and commercial development is concentrated in the upper two thirds of the LLC watershed, where travel times are such that these areas contribute to the peak flows measured at the gage. Development is concentrated in the lower third of the MC watershed, where it has had less effect on peak flows at the gage. Overall, the study indicates that relatively subtle differences between watershed characteristics and development patterns can result in significant differences in runoff and in how streamflow regimes may change in response to urbanization.

Patterns and age distribution of ground-water flow to streams

USGS Publications Warehouse

Modica, E.; Reilly, T.E.; Pollock, D.W.

1997-01-01

Simulations of ground-water flow in a generic aquifer system were made to characterize the topology of ground-water flow in the stream subsystem and to evaluate its relation to deeper ground-water flow. The flow models are patterned after hydraulic characteristics of aquifers of the Atlantic Coastal Plain and are based on numerical solutions to three-dimensional, steady-state, unconfined flow. The models were used to evaluate the effects of aquifer horizontal-to-vertical hydraulic conductivity ratios, aquifer thickness, and areal recharge rates on flow in the stream subsystem. A particle tracker was used to determine flow paths in a stream subsystem, to establish the relation between ground-water seepage to points along a simulated stream and its source area of flow, and to determine ground-water residence time in stream subsystems. In a geometrically simple aquifer system with accretion, the source area of flow to streams resembles an elongated ellipse that tapers in the downgradient direction. Increased recharge causes an expansion of the stream subsystem. The source area of flow to the stream expands predominantly toward the stream headwaters. Baseflow gain is also increased along the reach of the stream. A thin aquifer restricts ground-water flow and causes the source area of flow to expand near stream headwaters and also shifts the start-of-flow to the drainage basin divide. Increased aquifer anisotropy causes a lateral expansion of the source area of flow to streams. Ground-water seepage to the stream channel originates both from near- and far-recharge locations. The range in the lengths of flow paths that terminate at a point on a stream increase in the downstream direction. Consequently, the age distribution of ground water that seeps into the stream is skewed progressively older with distance downstream. Base flow ia an integration of ground water with varying age and potentially different water quality, depending on the source within the drainage basin. The quantitative results presented indicate that this integration can have a wide and complex residence time range and source distribution.

Use of the continuous slope-area method to estimate runoff in a network of ephemeral channels, southeast Arizona, USA

USGS Publications Warehouse

Stewart, Anne M.; Callegary, James B.; Smith, Christopher F.; Gupta, Hoshin V.; Leenhouts, James M.; Fritzinger, Robert A.

2012-01-01

The continuous slope-area (CSA) method is an innovative gaging method for indirect computation of complete-event discharge hydrographs that can be applied when direct measurement methods are unsafe, impractical, or impossible to apply. This paper reports on use of the method to produce event-specific discharge hydrographs in a network of sand-bedded ephemeral stream channels in southeast Arizona, USA, for water year 2008. The method provided satisfactory discharge estimates for flows that span channel banks, and for moderate to large flows, with about 10–16% uncertainty, respectively for total flow volume and peak flow, as compared to results obtained with an alternate method. Our results also suggest that the CSA method may be useful for estimating runoff of small flows, and during recessions, but with increased uncertainty.

How has climate change altered network connectivity in a mountain stream network?

NASA Astrophysics Data System (ADS)

Ward, A. S.; Schmadel, N.; Wondzell, S. M.; Johnson, S.

2017-12-01

Connectivity along river networks is broadly recognized as dynamic, with seasonal and event-based expansion and contraction of the network extent. Intermittently flowing streams are particularly important as they define a crucial threshold for continuously connected waters that enable migration by aquatic species. In the Pacific northwestern U.S., changes in atmospheric circulation have been found to alter rainfall patterns and result in decreased summer low-flows in the region. However, the impact of this climate dynamic on network connectivity is heretofore unstudied. Thus, we ask: How has connectivity in the riparian corridor changed in response to observed changes in climate? In this study we take the well-studied H.J. Andrews Experimental Forest as representative of mountain river networks in the Pacific northwestern U.S. First, we analyze 63 years of stream gauge information from a network of 11 gauges to document observed changes in timing and magnitude of stream discharge. We found declining magnitudes of seasonal low-flows and shifting seasonality of water export from the catchment, both of which we attribute to changes in precipitation timing and storage as snow vs. rainfall. Next, we use these discharge data to drive a reduced-complexity model of the river network to simulate network connectivity over 63 years. Model results show that network contraction (i.e., minimum network extent) has decreased over the past 63 years. Unexpectedly, the increasing winter peak flows did not correspond with increasing network expansion, suggesting a geologic control on maximum flowing network extent. We find dynamic expansion and contraction of the network primarily occurs during period of catchment discharge less than about 1 m3/s at the outlet, whereas the network extent is generally constant for discharges from 1 to 300 m3/s. Results of our study are of interest to scientists focused on connectivity as a control on ecological processes both directly (e.g., fish migration) and indirectly (e.g., stream temperature modeling). Additionally, our results inform management and regulatory needs such as estimating connectivity for entire river networks as a basis for regulation, and identifying the complexity of a shifting baseline in identifying a regulatory basis.

Water Resources Data, Florida, Water Year 2003 Volume 2A: South Florida Surface Water

USGS Publications Warehouse

Price, C.; Woolverton, J.; Overton, K.

2004-01-01

Water resources data for 2003 water year in Florida consists of continuous or daily discharge for 385 streams, periodic discharge for 13 streams, continuous or daily stage for 255 streams, periodic stage for 13 stream, peak discharge for 36 streams, and peak stage for 36 streams, continuous or daily elevations for 13 lakes, periodic elevations for 46 lakes, continuous ground-water levels for 441 wells, periodic ground-water levels for 1227 wells, quality of water data for 133 surface-water sites, and 308 wells. The data for South Florida included continuous or daily discharge for 72 streams, continuous or daily stage for 50 streams, no peak stage discharge for streams, 1 continuous elevation for lake, continuous ground-water levels for 237 wells, periodic ground-water levels for 248 wells, water quality for 25 surface-water sites, and 161 wells. These data represent the National Water Data System records collected by the U.S. Geological Survey and cooperation with local, state, and federal agencies in Florida.

Water Resources Data, Florida, Water Year 2003 Volume 2B: South Florida Ground Water

USGS Publications Warehouse

Prinos, S.; Irvin, R.; Byrne, M.

2004-01-01

Water resources data for 2003 water year in Florida consists of continuous or daily discharge for 385 streams, periodic discharge for 13 streams, continuous or daily stage for 255 streams, periodic stage for 13 stream, peak discharge for 36 streams, and peak stage for 36 streams, continuous or daily elevations for 13 lakes, periodic elevations for 46 lakes, continuous ground-water levels for 441 wells, periodic ground-water levels for 1227 wells, quality of water data for 133 surface-water sites, and 308 wells. The data for South Florida included continuous or daily discharge for 72 streams, continuous or daily stage for 50 streams, no peak stage discharge for streams, 1 continuous elevation for lake, continuous ground-water levels for 237 wells, periodic ground-water levels for 248 wells, water quality for 25 surface-water sites, and 161 wells. These data represent the National Water Data System records collected by the U.S. Geological Survey and cooperation with local, state, and federal agencies in Florida.

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.

The conversion of grasslands to forests in Southern South America: Shifting evapotranspiration, stream flow and groundwater dynamics

NASA Astrophysics Data System (ADS)

Jobbagy, E. G.; Nosetto, M. D.; Pineiro, G.; Farley, K. A.; Palmer, S. M.; Jackson, R. B.

2005-12-01

Vegetation changes, particularly those involving transitions between tree- and grass-dominated systems, often modify evaporation as a result of plant-mediated shifts in moisture access and demand. The establishment of tree plantations (fast growing eucalypts and pines) on native grasslands is emerging as a major land-use change, particularly in the Southern Hemisphere, where cheap land and labor, public subsidies, and prospective C sequestration rewards provide converging incentives. What are the hydrological consequences of grassland afforestation? How are crucial ecosystem services such as fresh water supply and hydrological regulation being affected? We explore these questions focusing on a) evapotranspiration, b) stream flow, and c) groundwater recharge-discharge patterns across a network of paired stands and small watershed occupied by native grassland and tree plantation in Argentina and Uruguay. Radiometric information obtained from Landsat satellite images was used to estimate daily evapotranspiration in >100 tree plantations and grasslands stands in the humid plains of the Uruguay River (mean annual precipitation, MAP= 1350 mm). In spite of their lower albedo, tree plantations were 0.5 C° cooler than grasslands. Energy balance calculations suggested 80% higher evapotranspiration in afforested plots with relative differences becoming larger during dry periods. Seasonal stream flow measurements in twelve paired watershed (50-500 Ha) in the hills of Comechingones (MAP= 800 mm) and Minas (MAP= 1200 mm) showed declining water yields following afforestation. Preliminary data in Cordoba showed four-fold reductions of base flow in the dry season and two-fold reductions of peak flow after storms. A network of twenty paired grassland-plantation stands covering a broad range of sediment textures in the Pampas (MAP= 1000 mm, typical groundwater depth= 1-5 m) showed increased groundwater salinity in afforested stands (plantation:grassland salinity ratio = 1.2, 10, and 1.7 in coarse, fine, and intermediate texture sediments, respectively). Local groundwater depression of 0.1 to 1.7 m under tree plantation was widespread. Afforested stands showed diurnal water level fluctuations (0.015 to 0.08 m, night peak) on intermediate to coarse sediments but not in fine textured ones. Groundwater level and salinity shifts suggest reduced recharge in all afforested stands. Phreatophytic discharge was evident only in coarse and intermediate textured sediments. The impact of grassland afforestation on evapotranspiration, stream flow, and ground water highlights the important role of vegetation as a hydrological driver and suggests critical trade-offs between timber production or C sequestration and freshwater supply. Afforestation, however, can also play a positive role regulating floods, perhaps helping to counteract the hydrological impacts of agriculture, which tend to increase water yield.

Traveltime and reaeration characteristics for a reach of the Rio Grande, Albuquerque, New Mexico, October 1991

USGS Publications Warehouse

Waltemeyer, S.D.

1994-01-01

Traveltime characteristics were determined using stream-velocity data and tracer-dye data for a reach of the Rio Grande. Traveltimes determined by the stream-velocity method were virtually the same as those determined by the tracer-dye and tracer-gas technique. The mean velocity of the stream was 1.12 miles per hour at a flow of about 300 cubic feet per second. Reaeration characteristics were determined using a propane tracer gas and a tracer-dye (rhodamine WT). Reaeration coefficients were adjusted for water temperature and the effects of wind movement on the water surface. The peak method-adjusted reaeration-coefficient mean value for the reach was 7.0 per day and ranged from 4.6 to 8.3 per day. The area method-adjusted reaeration- coefficient mean value for the reach was 7.7 per day and ranged from 5.5 to 10.4 per day.

Slope-Area Computation Program Graphical User Interface 1.0—A Preprocessing and Postprocessing Tool for Estimating Peak Flood Discharge Using the Slope-Area Method

USGS Publications Warehouse

Bradley, D. Nathan

2012-01-01

The slope-area method is a technique for estimating the peak discharge of a flood after the water has receded (Dalrymple and Benson, 1967). This type of discharge estimate is called an “indirect measurement” because it relies on evidence left behind by the flood, such as high-water marks (HWMs) on trees or buildings. These indicators of flood stage are combined with measurements of the cross-sectional geometry of the stream, estimates of channel roughness, and a mathematical model that balances the total energy of the flow between cross sections. This is in contrast to a “direct” measurement of discharge during the flood where cross-sectional area is measured and a current meter or acoustic equipment is used to measure the water velocity. When a direct discharge measurement cannot be made at a gage during high flows because of logistics or safety reasons, an indirect measurement of a peak discharge is useful for defining the high-flow section of the stage-discharge relation (rating curve) at the stream gage, resulting in more accurate computation of high flows. The Slope-Area Computation program (SAC; Fulford, 1994) is an implementation of the slope-area method that computes a peak-discharge estimate from inputs of water-surface slope (from surveyed HWMs), channel geometry, and estimated channel roughness. SAC is a command line program written in Fortran that reads input data from a formatted text file and prints results to another formatted text file. Preparing the input file can be time-consuming and prone to errors. This document describes the SAC graphical user interface (GUI), a crossplatform “wrapper” application that prepares the SAC input file, executes the program, and helps the user interpret the output. The SAC GUI is an update and enhancement of the slope-area method (SAM; Hortness, 2004; Berenbrock, 1996), an earlier spreadsheet tool used to aid field personnel in the completion of a slope-area measurement. The SAC GUI reads survey data, develops a plan-view plot, water-surface profile, cross-section plots, and develops the SAC input file. The SAC GUI also develops HEC-2 files that can be imported into HEC–RAS.

High-frequency DOC and nitrate measurements provide new insights into their export and their relationships to rainfall-runoff processes

NASA Astrophysics Data System (ADS)

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

2015-04-01

Over the past decades, stream sampling protocols for environmental tracers were often limited by logistical and technological constraints. Long-term sampling programs would typically rely on weekly sampling campaigns, while high-frequency sampling would remain restricted to a few days or hours at best. We stipulate that the currently predominant sampling protocols are too coarse to capture and understand the full amplitude of rainfall-runoff processes and its relation to water quality fluctuations. Weekly sampling protocols are not suited to get insights into the hydrological system during high flow conditions. Likewise, high frequency measurements of a few isolated events do not allow grasping inter-event variability in contributions and processes. Our working hypothesis is based on the potential of a new generation of field-deployable instruments for measuring environmental tracers at high temporal frequencies over an extended period. With this new generation of instruments we expect to gain new insights into rainfall-runoff dynamics, both at intra- and inter-event scales. Here, we present the results of one year of DOC and nitrate measurements with the field deployable UV-Vis spectrometer spectro::lyser (scan Messtechnik GmbH). The instrument measures the absorption spectrum from 220 to 720 nm in situ and at high frequencies and derives DOC and nitrate concentrations. The measurements were carried out at 15 minutes intervals in the Weierbach catchment (0.47 km2) in Luxemburg. This fully forested catchment is characterized by cambisol soils and fractured schist as underlying bedrock. The time series of DOC and nitrate give insights into the high frequency dynamics of stream water. Peaks in DOC concentrations are closely linked to discharge peaks that occur during or right after a rainfall event. Those first discharge peaks can be linked to fast near surface runoff processes and are responsible for a remarkable amount of DOC export. A special characterisation of the Weierbach catchment are the delayed second peaks a few days after the rainfall event. Nitrate concentrations are following this second peak. We assume that this delayed response is going back to subsurface or upper groundwater flows, with nitrate enriched water. On an inter-event scale during low flow / base flow conditions, we observe interesting diurnal patterns of both DOC and nitrate concentrations. Overall, the long-term high-frequency measurements of DOC and nitrate provide us the opportunity to separate different rainfall-runoff processes and link the amount of DOC and nitrate export to them to quantify the overall relevance of the different processes.

Water Resources Data, Florida, Water Year 2003, Volume 3A: Southwest Florida Surface Water

USGS Publications Warehouse

Kane, R.L.; Fletcher, W.L.

2004-01-01

Water resources data for the 2003 water year in Florida consist of continuous or daily discharges for 385 streams, periodic discharge for 13 streams, continuous daily stage for 255 streams, periodic stage for 13 streams, peak stage for 36 streams and peak discharge for 36 streams, continuous or daily elevations for 13 lakes, periodic elevations for 46 lakes; continuous ground-water levels for 441 wells, periodic ground-water levels for 1,227 wells, and quality-of-water data for 133 surface-water sites and 308 wells. The data for Southwest Florida include records of stage, discharge, and water quality of streams; stage, contents, water quality of lakes and reservoirs, and water levels and water quality of ground-water wells. Volume 3A contains continuous or daily discharge for 103 streams, periodic discharge for 7 streams, continuous or daily stage for 67 streams, periodic stage for 13 streams, peak stage and discharge for 8 streams, continuous or daily elevations for 2 lakes, periodic elevations for 26 lakes, and quality-of-water data for 62 surface-water sites. These data represent the national Water Data System records collected by the U.S. Geological Survey and cooperating local, state, and federal agencies in Florida.

Accounting for mean-flow periodicity in turbulence closures

NASA Astrophysics Data System (ADS)

Younis, Bassam A.; Zhou, Ye

2006-01-01

Measurements of the turbulence energy spectrum in the unsteady wakes of bodies in uniform incident streams clearly show the presence of a distinct peak in energy supply that occurs at the Strouhal frequency and whose presence implies a strong and direct interaction between the organized mean-flow unsteadiness and the random turbulence motions. It is argued here that the well-documented failure of conventional turbulence closures in capturing the main features of unsteady flows is largely due to their inability to properly account for the modifications in the energy spectrum wrought by these interactions. We derive a simple modification to the turbulence length-scale determining equation based on analysis of a distorted energy spectrum, and verify the result by computations of vortex shedding behind a square cylinder.

Simulating land-use changes and stormwater-detention basins and evaluating their effect on peak streamflows and stream-water quality in Irondequoit Creek basin, New York—A user's manual for HSPF and GenScn

USGS Publications Warehouse

Coon, William F.

2003-01-01

A computer model of hydrologic and water-quality processes of the Irondequoit Creek basin in Monroe and Ontario Counties, N.Y., was developed during 2000-02 to enable water-resources managers to simulate the effects of future development and stormwater-detention basins on peak flows and water quality of Irondequoit Creek and its tributaries. The model was developed with the program Hydrological Simulation Program-Fortran (HSPF) such that proposed or hypothetical land-use changes and instream stormwater-detention basins could be simulated, and their effects on peak flows and loads of total suspended solids, total phosphorus, ammonia-plus-organic nitrogen, and nitrate-plus-nitrite nitrogen could be analyzed, through an interactive computer program known as Generation and Analysis of Model Simulation Scenarios for Watersheds (GenScn). This report is a user's manual written to guide the Irondequoit Creek Watershed Collaborative in (1) the creation of land-use and flow-detention scenarios for simulation by the HSPF model, and (2) the use of GenScn to analyze the results of these simulations. These analyses can, in turn, aid the group in making basin-wide water-resources-management decisions.

Changes in Stream Peak Flow and Regulation in Naoli River Watershed as a Result of Wetland Loss

PubMed Central

Yao, Yunlong; Wang, Lei; Lv, Xianguo; Yu, Hongxian; Li, Guofu

2014-01-01

Hydrology helps determine the character of wetlands; wetlands, in turn, regulate water flow, which influences regional hydrology. To understand these dynamics, we studied the Naoli basin where, from 1954 to 2005, intensive marshland cultivation took place, and the watershed's wetland area declined from 94.4 × 104 ha to 17.8 × 104 ha. More than 80% of the wetland area loss was due to conversion to farmland, especially from 1976 to 1986. The processes of transforming wetlands to cultivated land in the whole Naoli basin and subbasins can be described using a first order exponential decay model. To quantify the effects of wetlands cultivation, we analyzed daily rainfall and streamflow data measured from 1955 to 2005 at two stations (Baoqing Station and Caizuizi Station). We defined a streamflow regulation index (SRI) and applied a Mann-Kendall-Sneyers test to further analyze the data. As the wetland area decreased, the peak streamflow at the Caizuizi station increased, and less precipitation generated heavier peak flows, as the runoff was faster than before. The SRI from 1959 to 2005 showed an increasing trend; the SRI rate of increase was 0.05/10a, demonstrating that the watershed's regulation of streamflow regulation was declined as the wetlands disappeared. PMID:25114956

Instrumenting an upland research catchment in Canterbury, New Zealand to study controls on variability of soil moisture, shallow groundwater and streamflow

NASA Astrophysics Data System (ADS)

McMillan, Hilary; Srinivasan, Ms

2015-04-01

Hydrologists recognise the importance of vertical drainage and deep flow paths in runoff generation, even in headwater catchments. Both soil and groundwater stores are highly variable over multiple scales, and the distribution of water has a strong control on flow rates and timing. In this study, we instrumented an upland headwater catchment in New Zealand to measure the temporal and spatial variation in unsaturated and saturated-zone responses. In NZ, upland catchments are the source of much of the water used in lowland agriculture, but the hydrology of such catchments and their role in water partitioning, storage and transport is poorly understood. The study area is the Langs Gully catchment in the North Branch of the Waipara River, Canterbury: this catchment was chosen to be representative of the foothills environment, with lightly managed dryland pasture and native Matagouri shrub vegetation cover. Over a period of 16 months we measured continuous soil moisture at 32 locations and near-surface water table (< 2 m) at 14 locations, as well as measuring flow at 3 stream gauges. The distributed measurement sites were located to allow comparisons between North and South facing locations, near-stream versus hillslope locations, and convergent versus divergent hillslopes. We found that temporal variability is strongly controlled by the climatic seasonal cycle, for both soil moisture and water table, and for both the mean and extremes of their distributions. Groundwater is a larger water storage component than soil moisture, and the difference increases with catchment wetness. The spatial standard deviation of both soil moisture and groundwater is larger in winter than in summer. It peaks during rainfall events due to partial saturation of the catchment, and also rises in spring as different locations dry out at different rates. The most important controls on spatial variability are aspect and distance from stream. South-facing and near-stream locations have higher water tables and more, larger soil moisture wetting events. Typical hydrological models do not explicitly account for aspect, but our results suggest that it is an important factor in hillslope runoff generation. Co-measurement of soil moisture and water table level allowed us to identify interrelationships between the two. Locations where water tables peaked closest to the surface had consistently wetter soils and higher water tables. These wetter sites were the same across seasons. However, temporary patterns of strong soil moisture response to summer storms did not correspond to the wetter sites. Total catchment spatial variability is composed of multiple variability sources, and the dominant type is sensitive to those stores that are close to a threshold such as field capacity or saturation. Therefore, we classified spatial variability as 'summer mode' or 'winter mode'. In summer mode, variability is controlled by shallow processes e.g. interactions of water with soils and vegetation. In winter mode, variability is controlled by deeper processes e.g. groundwater movement and bypass flow. Double flow peaks observed during some events show the direct impact of groundwater variability on runoff generation. Our results suggest that emergent catchment behaviour depends on the combination of these multiple, time varying components of variability.

Hydrological Controls on Nutrient Concentrations and Fluxes in Agricultural Catchments

NASA Astrophysics Data System (ADS)

Petry, J.; Soulsby, C.

2002-12-01

This investigation into diffuse agricultural pollution and the hydrological controls that exert a strong influence on both nutrient concentrations and fluxes, was conducted in an intensively farmed lowland catchment in north-east Scotland. The study focuses on spatial and seasonal variations in nutrient concentrations and fluxes at the catchment scale, over a 15-month period. The water quality of the 14.5 km2 Newmills Burn catchment has relatively high nutrient levels with mean concentrations of NO3-N and NH3-N at 6.09 mg/l and 0.28 mg/l respectively. Average PO4-P concentrations are 0.06 mg/l. Over short timescales nutrient concentrations and fluxes are greatest during storm events when PO4-P and NH3-N are mobilised by overland flow in riparian areas, where soils have been compacted by livestock or machinery. Delivery of deeper soil water in subsurface storm flow, facilitated by agricultural under-drainage, produces a marked increase in NO3-N (6.9 mg/l) concentrations on the hydrograph recession limb. A more detailed insight into the catchment response to storm events, and in particular the response of the hydrological pathways which provide the main sources of runoff during storm events, was gained by sampling stream water at 2-hourly intervals during 5 events. End Member Mixing Analysis (EMMA) was carried out using event specific end-member chemistries to differentiate three catchment-scale hydrological pathways (overland flow, subsurface storm flow, groundwater flow) on the basis of observed Si and NO3-N concentrations in sampled source waters. Results show that overland flow generally dominates the storm peak and provides the main flow path by which P is transferred to stream channels during storm events, whilst subsurface storm flows usually dominate the storm hydrograph volumetrically and route NO3-rich soil water to the stream. The study shows that altering hydrological pathways in a catchment can have implications for nutrient management. Whilst buffer strips can reduce the delivery of NH3-N and PO4-P by overland flow to stream channels during storm events, the management of N-rich storm runoff as NO3 via sub-surface drains would require significant interference with the drainage network. This could have a negative impact on agricultural production in the catchment.

Measurement of water quality of high-altitude wilderness streams: Cloud Peak Wilderness, Bighorn National Forest, Wyoming

Treesearch

Karen Ferguson

2007-01-01

The measurement of water quality and stream health in wilderness areas is made difficult by the need to use non-motorized modes of travel. In Wyoming, data on streams in the high-altitude Cloud Peak Wilderness are scarce. The monitoring of stream health of the Tongue, Powder and Big Horn Rivers at lower altitudes can be made more meaningful by the collection of...

Initial Circulation and Peak Vorticity Behavior of Vortices Shed from Airfoil Vortex Generators

NASA Technical Reports Server (NTRS)

Wendt, Bruce J.; Biesiadny, Tom (Technical Monitor)

2001-01-01

An extensive parametric study of vortices shed from airfoil vortex generators has been conducted to determine the dependence of initial vortex circulation and peak vorticity on elements of the airfoil geometry and impinging flow conditions. These elements include the airfoil angle of attack, chord length, span, aspect ratio, local boundary layer thickness, and free stream Mach number. In addition, the influence of airfoil-to-airfoil spacing on the circulation and peak vorticity has been examined for pairs of co-rotating and counter-rotating vortices. The vortex generators were symmetric airfoils having a NACA-0012 cross-sectional profile. These airfoils were mounted either in isolation, or in pairs, on the surface of a straight pipe. The turbulent boundary layer thickness to pipe radius ratio was about 17 percent. The circulation and peak vorticity data were derived from cross-plane velocity measurements acquired with a seven-hole probe at one chord-length downstream of the airfoil trailing edge location. The circulation is observed to be proportional to the free-stream Mach number, the angle-of-attack, and the span-to-boundary layer thickness ratio. With these parameters held constant, the circulation is observed to fall off in monotonic fashion with increasing airfoil aspect ratio. The peak vorticity is also observed to be proportional to the free-stream Mach number, the airfoil angle-of-attack, and the span-to-boundary layer thickness ratio. Unlike circulation, however, the peak vorticity is observed to increase with increasing aspect ratio, reaching a peak value at an aspect ratio of about 2.0 before falling off again at higher values of aspect ratio. Co-rotating vortices shed from closely spaced pairs of airfoils have values of circulation and peak vorticity under those values found for vortices shed from isolated airfoils of the same geometry. Conversely, counter-rotating vortices show enhanced values of circulation and peak vorticity when compared to values obtained in isolation. The circulation may be accurately modeled with an expression based on Prandtl's relationship between finite airfoil circulation and airfoil geometry. A correlation for the peak vorticity has been derived from a conservation relationship equating the moment at the airfoil tip to the rate of angular momentum production of the shed vortex, modeled as a Lamb (ideal viscous) vortex. This technique provides excellent qualitative agreement to the observed behavior of peak vorticity for low aspect ratio airfoils typically used as vortex generators.

Regional ground-water discharge to large streams in the upper coastal plain of South Carolina and parts of North Carolina and Georgia

USGS Publications Warehouse

Aucott, W.R.; Meadows, R.S.; Patterson, G.G.

1987-01-01

Base flow was computed to estimate discharge from regional aquifers for six large streams in the upper Coastal Plain of South Carolina and parts of North Carolina and Georgia. Aquifers that sustain the base flow of both large and small streams are stratified into shallow and deep flow systems. Base-flow during dry conditions on main stems of large streams was assumed to be the discharge from the deep groundwater flow system. Six streams were analyzed: the Savannah, South and North Fork Edisto, Lynches, Pee Dee, and the Luber Rivers. Stream reaches in the Upper Coastal Plain were studied because of the relatively large aquifer discharge in these areas in comparison to the lower Coastal Plain. Estimates of discharge from the deep groundwater flow system to the six large streams averaged 1.8 cu ft/sec/mi of stream and 0.11 cu ft/sec/sq mi of surface drainage area. The estimates were made by subtracting all tributary inflows from the discharge gain between two gaging stations on a large stream during an extreme low-flow period. These estimates pertain only to flow in the deep groundwater flow system. Shallow flow systems and total base flow are > flow in the deep system. (USGS)

Effects of Debris Flows on Stream Ecosystems of the Klamath Mountains, Northern California

NASA Astrophysics Data System (ADS)

Cover, M. R.; Delafuente, J. A.; Resh, V. H.

2006-12-01

We examined the long-term effects of debris flows on channel characteristics and aquatic food webs in steep (0.04-0.06 slope), small (4-6 m wide) streams. A large rain-on-snow storm event in January 1997 resulted in numerous landslides and debris flows throughout many basins in the Klamath Mountains of northern California. Debris floods resulted in extensive impacts throughout entire drainage networks, including mobilization of valley floor deposits and removal of vegetation. Comparing 5 streams scoured by debris flows in 1997 and 5 streams that had not been scoured as recently, we determined that debris-flows decreased channel complexity by reducing alluvial step frequency and large woody debris volumes. Unscoured streams had more diverse riparian vegetation, whereas scoured streams were dominated by dense, even-aged stands of white alder (Alnus rhombiflia). Benthic invertebrate shredders, especially nemourid and peltoperlid stoneflies, were more abundant and diverse in unscoured streams, reflecting the more diverse allochthonous resources. Debris flows resulted in increased variability in canopy cover, depending on degree of alder recolonization. Periphyton biomass was higher in unscoured streams, but primary production was greater in the recently scoured streams, suggesting that invertebrate grazers kept algal assemblages in an early successional state. Glossosomatid caddisflies were predominant scrapers in scoured streams; heptageniid mayflies were abundant in unscoured streams. Rainbow trout (Oncorhynchus mykiss) were of similar abundance in scoured and unscoured streams, but scoured streams were dominated by young-of-the-year fish while older juveniles were more abundant in unscoured streams. Differences in the presence of cold-water (Doroneuria) versus warm-water (Calineuria) perlid stoneflies suggest that debris flows have altered stream temperatures. Debris flows have long-lasting impacts on stream communities, primarily through the cascading effects of removal of riparian vegetation. Because debris flow frequency increases following road construction and timber harvest, the long-term biological effects of debris flows on stream ecosystems, including anadromous fish populations, needs to be considered in forest management decisions.

Dissolved Organic Carbon and Natural Terrestrial Sequestration Potential in Volcanic Terrain, San Juan Mountains, Colorado

NASA Astrophysics Data System (ADS)

Yager, D. B.; Burchell, A.; Johnson, R. H.; Kugel, M.; Aiken, G.; Dick, R.

2009-12-01

The need to reduce atmospheric CO2 levels has stimulated studies to understand and quantify carbon sinks and sources. Soils represent a potentially significant natural terrestrial carbon sequestration (NTS) reservoir. This project is part of a collaborative effort to characterize carbon (C) stability in temperate soils. To examine the potential for dissolved organic carbon (DOC) values as a qualitative indicator of C-stability, peak-flow (1500 ft3/s) and low-flow (200 ft3/s) samples from surface and ground waters were measured for DOC. DOC concentrations are generally low. Median peak-flow values from all sample sites (mg/L) were: streams (0.9); seeps (1.2); wells (0.45). Median low-flow values were: streams (0.7); seeps (0.75); wells (0.5). Median DOC values decrease between June and September 0.45 mg/L for seeps, and 0.2 mg/L for streams. Elevated DOC in some ground waters as compared to surface waters indicates increased contact time with soil organic matter. Elevated peak-flow DOC in areas with propylitically-altered bedrocks, composed of a secondary acid neutralizing assemblage of calcite-chlorite-epidote, reflects increased microbial and vegetation activity as compared to reduced organic matter accumulation in highly-altered terrain composed of an acid generating assemblage with abundant pyrite. Waters sampled in propylitically-altered bedrock terrain exhibit the lowest values during low-flow and suggest bedrock alteration type may influence DOC. Previous studies revealed undisturbed soils sampled have 2 to 6 times greater total organic soil carbon (TOSC) than global averages. Forest soils underlain by intermediate to mafic volcanic bedrock have the highest C (34.15 wt%), C: N (43) and arylsulfatase enzyme activity (ave. 278, high 461 µg p-nitrophenol/g/h). Unreclaimed mine sites have the lowest C (0 to 0.78 wt%), and arylsulfatase enzyme activity (0 to 41). Radiocarbon dates on charcoal collected from paleo-burn horizons illustrate Rocky Mountain soils may represent an old and if undisturbed, stable carbon pool (500 -5,440 ± 40 yrs B.P). Undisturbed and reclaimed soils derived from propylitic bedrocks also exhibit high TOSC (13.5 - 25.6 wt%), C: N (27), arylsulfatase (338). This is consistent with earlier studies in which propylitic bedrocks were identified as having a high acid-neutralizing capacity (ANC). Observations at natural reclamation sites suggest “bio-geo-mimicry” techniques that use ANC rock plus other soil amendments (biochar, nutrients, mycorrhizea, seeding) may aid reclamation measures and support carbon sequestration. The data demonstrate that volcanic-hosted watersheds may exhibit both high TOSC and low DOC. This is attributed to: host rock-weathering release of nutrients important for soil productivity, ANC, formation of secondary mineral carbonates; development of intermediate soil aggregates and adsorption-enhancing clays that stabilize C and N, environmental factors such as climate, moisture retention, and land use. Future work will explore the potential of DOC flux as a proxy for NTS potential.

Natural and Diverted Low-Flow Duration Discharges for Streams Affected by the Waiahole Ditch System, Windward O`ahu, Hawai`i

USGS Publications Warehouse

Yeung, Chiu W.; Fontaine, Richard A.

2007-01-01

For nearly a century, the Waiahole Ditch System has diverted an average of approximately 27 million gallons per day of water from the wet, northeastern part of windward O`ahu, Hawai`i, to the dry, central part of the island to meet irrigation needs. The system intercepts large amounts of dike-impounded ground water at high altitudes (above approximately 700 to 800 ft) that previously discharged to Waiahole (and its tributaries Waianu and Uwao), Waikane, and Kahana Streams through seeps and springs. Diversion of this ground water has significantly diminished low flows in these streams. Estimates of natural and diverted flows are needed by water managers for (1) setting permanent instream flow standards to protect, enhance, and reestablish beneficial instream uses of water in the diverted streams and (2) allocating the diverted water for instream and offstream uses. Data collected before construction of the Waiahole Ditch System reflect natural (undiverted) flow conditions. Natural low-flow duration discharges for percentiles ranging from 50 to 99 percent were estimated for four sites at altitudes of 75 to 320 feet in Waiahole Stream (and its tributaries Waianu and Uwao Streams), for six sites at altitudes of 10 to 220 feet in Waikane Stream, and for three sites at altitudes of 30 to 80 feet in Kahana Stream. Among the available low-flow estimates along each affected stream, the highest natural Q50 (median) flows on Waiahole (altitude 250 ft), Waianu (altitude 75 ft), Waikane (altitude 75 ft), and Kahana Streams (altitude 30 ft) are 13, 7.0, 5.5, and 22 million gallons per day, respectively. Q50 (median) is just one of five duration percentiles presented in this report to quantify low-flow discharges. All flow-duration estimates were adjusted to a common period of 1960-2004 (called the base period). Natural flow-duration estimates compared favorably with limited pre-ditch streamflow data available for Waiahole and Kahana Streams. Data collected since construction of the ditch system reflect diverted flow conditions, which can be further divided into pre-release and post-release periods - several flow releases to Waiahole, Waianu, and Waikane Streams were initiated between December 1994 and October 2002. Comparison of pre-release to natural flows indicate that the effects of the Waiahole Ditch System diversion are consistently greater at lower low-flow conditions (Q99 to Q90) than at higher low-flow conditions (Q75 to Q50). Results also indicate that the effects of the diversion become less significant as the streams gain additional ground water at lower altitudes. For Waiahole Stream, pre-release flows range from 25 to 28 percent of natural flows at an altitude of 250 feet and from 19 to 20 percent at an altitude of 320 feet. For Waikane Stream, pre-release flows range from 30 to 46 percent of natural flows at an altitude of 10 feet and from 7 to 19 percent at an altitude of 220 feet. For Kahana Stream, pre-release flows range from 65 to 72 percent of natural flows at an altitude of 30 feet and from 58 to 71 percent at an altitude of 80 feet. Estimates of post-release flows were compared with estimates of natural flows to assess how closely current streamflows are to natural conditions. For Waianu Stream, post-release flows at an altitude of 75 feet are 41 to 46 percent lower than corresponding natural flows. For Waikane Stream, post-release flows at an altitude of 75 feet are within 12 percent of the corresponding natural flows. Comparisons of pre-release and post-release flows for Waikane Stream at altitudes of 10 to 220 feet were used to assess downstream changes in flow along the stream reach where flow releases were made. For a particular stream altitude, proportions of pre-release to post-release flows associated with median flows are consistently greater than proportions associated with lower low flows because the relative effect of the flow release is smaller at higher low flows. Similarly, for a particular f

Calibration of AN Acoustic Sensor (geophone) for Continuous Bedload Monitoring in Mountainous Streams

NASA Astrophysics Data System (ADS)

Tsakiris, A. G.; Papanicolaou, T.

2010-12-01

Measurement of bedload rates is a crucial component in the study of alluvial processes in mountainous streams. Stream restoration efforts, the validation of morphodynamic models and the calibration empirical transport formulae rely on accurate bedload transport measurements. Bedload measurements using traditional methods (e.g. samplers, traps) are time consuming, resource intensive and not always feasible, especially at higher flow conditions. These limitations could potentially be addressed by acoustic instruments, which may provide unattended, continuous bedload measurements even at higher flow conditions, provided that these instruments are properly calibrated. The objective of this study is to calibrate an acoustic instrument (geophone) for performing bedload measurements in a well-monitored laboratory environment at conditions corresponding to low flow regime in mountainous streams. The geophone was manufactured by ClampOn® and was attached to the bottom of a steel plate with dimensions 0.15x0.15 m. The geophone registers the energy of the acoustic signal produced by the movement of the bedload particles over the steel plate with time resolution of one second. The plate-sensor system was installed in an acrylic housing such that the steel plate top surface was at the same level with the surface of a flat porous bed consisting of unisize spheres with diameter 19.1 mm. Unisize spherical glass particles, 15.9 mm in diameter, were preplaced along a 2 m long section upstream of the sensor, and were entrained over the steel plate. In these experiments, the geophone records spanned the complete experiment duratio. Plan view video of the particle movement over the steel plate was recorded via an overhead camera, and was used to calculate the actual bedload rate over the steel plate. Synchronized analysis of this plan view video and the geophone time series revealed that the geophone detected 62% of the bedload particles passing over the steel plate, which triggered discernable peaks in the time series. The bedload rate over the plate correlated as a power law relation with the magnitude of the registered peaks. This relation can be used for estimating the temporal variations of bedload from the record of the geophones records, which can produce continuous records and thus bedload measurements over extended time periods. Future research on the geophones is guaranteed and will aim on calibrating the geophones for particle movement at higher flow conditions where general sediment movement and possibly particle saltation occur.

Spatial and temporal spawning dynamics of native westslope cutthroat trout, Oncorhynchus clarkii lewisi, introduced rainbow trout, Oncorhynchus mykiss, and their hybrids

USGS Publications Warehouse

Muhlfeld, C.C.; McMahon, T.E.; Belcer, D.; Kershner, J.L.

2009-01-01

We used radiotelemetry to assess spatial and temporal spawning distributions of native westslope cutthroat trout (Oncorhynchus clarkii lewisi; WCT), introduced rainbow trout (Oncorhynchus mykiss; RBT), and their hybrids in the upper Flathead River system, Montana (USA) and British Columbia (Canada), from 2000 to 2007. Radio-tagged trout (N = 125) moved upriver towards spawning sites as flows increased during spring runoff and spawned in 29 tributaries. WCT migrated greater distances and spawned in headwater streams during peak flows and as flows declined, whereas RBT and RBT hybrids (backcrosses to RBT) spawned earlier during increasing flows and lower in the system. WCT hybrids (backcrosses to WCT) spawned intermediately in time and space to WCT and RBT and RBT hybrids. Both hybrid groups and RBT, however, spawned over time periods that produced temporal overlap with spawning WCT in most years. Our data indicate that hybridization is spreading via long-distance movements of individuals with high amounts of RBT admixture into WCT streams and stepping-stone invasion at small scales by later generation backcrosses. This study provides evidence that hybridization increases the likelihood of reproductive overlap in time and space, promoting extinction by introgression, and that the spread of hybridization is likely to continue if hybrid source populations are not reduced or eliminated.

Effects of groundwater levels and headwater wetlands on streamflow in the Charlie Creek basin, Peace River watershed, west-central Florida

USGS Publications Warehouse

Lee, T.M.; Sacks, L.A.; Hughes, J.D.

2010-01-01

The Charlie Creek basin was studied from April 2004 to December 2005 to better understand how groundwater levels in the underlying aquifers and storage and overflow of water from headwater wetlands preserve the streamflows exiting this least-developed tributary basin of the Peace River watershed. The hydrogeologic framework, physical characteristics, and streamflow were described and quantified for five subbasins of the 330-square mile Charlie Creek basin, allowing the contribution of its headwaters area and tributary subbasins to be separately quantified. A MIKE SHE model simulation of the integrated surface-water and groundwater flow processes in the basin was used to simulate daily streamflow observed over 21 months in 2004 and 2005 at five streamflow stations, and to quantify the monthly and annual water budgets for the five subbasins including the changing amount of water stored in wetlands. Groundwater heads were mapped in Zone 2 of the intermediate aquifer system and in the Upper Floridan aquifer, and were used to interpret the location of artesian head conditions in the Charlie Creek basin and its relation to streamflow. Artesian conditions in the intermediate aquifer system induce upward groundwater flow into the surficial aquifer and help sustain base flow which supplies about two-thirds of the streamflow from the Charlie Creek basin. Seepage measurements confirmed seepage inflow to Charlie Creek during the study period. The upper half of the basin, comprised largely of the Upper Charlie Creek subbasin, has lower runoff potential than the lower basin, more storage of runoff in wetlands, and periodically generates no streamflow. Artesian head conditions in the intermediate aquifer system were widespread in the upper half of the Charlie Creek basin, preventing downward leakage from expansive areas of wetlands and enabling them to act as headwaters to Charlie Creek once their storage requirements were met. Currently, the dynamic balance between wetland storage, rainfall-runoff processes, and groundwater-level differences in the upper basin allow it to generate approximately half of the streamflow from the Charlie Creek basin. Therefore, future development in the upper basin that would alter the hydraulic connectivity of wetlands during high flow conditions or expand recharging groundwater conditions could substantially affect streamflow in Charlie Creek. LIDAR (Light detection and ranging) based topographic maps and integrated modeling results were used to quantify the water stored in wetlands and other topographic depressions, and to describe the network of shallow stream channels connecting wetlands to Charlie Creek and its tributaries over distances of several thousand feet. Peak flows at all but one streamflow station were underpredicted in MIKE SHE simulations, possibly because the hydraulics of surface channels connecting wetlands to stream channels were not explicitly simulated in the model. Explicitly simulating the smaller channels connecting wetlands and stream channels should improve the ability of future watershed models to simulate peak flows in streams with headwater wetlands. The runoff potential was greater in the lower half of the Charlie Creek basin than in the upper half, and the streambed of Charlie Creek had greater potential to both directly gain streamflow from groundwater and lose streamflow to groundwater. Charlie Creek is more incised into the surficial aquifer in the lower basin than in the upper basin, and the streambed intersects the top of the intermediate aquifer system at two known locations. Groundwater levels in the intermediate aquifer system varied widely in the lower half of the basin from artesian conditions inducing upward flow toward the surficial aquifer and streams, to recharging conditions allowing downward flow and stream leakage. Recharge areas were greatest in May 2004 when rainfall was at a seasonal low and irrigation pumping was at a seasonal high. Recharge conditions

High levels of endocrine pollutants in US streams during low flow due to insufficient wastewater dilution

NASA Astrophysics Data System (ADS)

Rice, Jacelyn; Westerhoff, Paul

2017-08-01

Wastewater discharges from publicly owned treatment works are a significant source of endocrine disruptors and other contaminants to the aquatic environment in the US. Although remaining pollutants in wastewater pose environmental risks, treated wastewater is also a primary source of stream flow, which in turn is critical in maintaining many aquatic and riparian wildlife habitats. Here we calculate the dilution factor--the ratio of flow in the stream receiving discharge to the flow of wastewater discharge--for over 14,000 receiving streams in the continental US using streamflow observations and a spatially explicit watershed-scale hydraulic model. We found that wastewater discharges make up more than 50% of in-stream flow for over 900 streams. However, in 1,049 streams that experienced exceptional low-flow conditions, the dilution factors in 635 of those streams fell so low during those conditions that the safety threshold for concentrations of one endocrine disrupting compound was exceeded, and in roughly a third of those streams, the threshold was exceeded for two compounds. We suggest that streams are vulnerable to public wastewater discharge of contaminants under low-flow conditions, at a time when wastewater discharges are likely to be most important for maintaining stream flow for smaller sized river systems.

The effects of Missouri River mainstem reservoir system operations on 2011 flooding using a Precipitation-Runoff Modeling System model: Chapter K in 2011 Floods of the Central United States

USGS Publications Warehouse

Haj, Adel E.; Christiansen, Daniel E.; Viger, Roland J.

2014-01-01

In 2011 the Missouri River Mainstem Reservoir System (Reservoir System) experienced the largest volume of flood waters since the initiation of record-keeping in the nineteenth century. The high levels of runoff from both snowpack and rainfall stressed the Reservoir System’s capacity to control flood waters and caused massive damage and disruption along the river. The flooding and resulting damage along the Missouri River brought increased public attention to the U.S. Army Corps of Engineers (USACE) operation of the Reservoir System. To help understand the effects of Reservoir System operation on the 2011 Missouri River flood flows, the U.S. Geological Survey Precipitation-Runoff Modeling System was used to construct a model of the Missouri River Basin to simulate flows at streamgages and dam locations with the effects of Reservoir System operation (regulation) on flow removed. Statistical tests indicate that the Missouri River Precipitation-Runoff Modeling System model is a good fit for high-flow monthly and annual stream flow estimation. A comparison of simulated unregulated flows and measured regulated flows show that regulation greatly reduced spring peak flow events, consolidated two summer peak flow events to one with a markedly decreased magnitude, and maintained higher than normal base flow beyond the end of water year 2011. Further comparison of results indicate that without regulation, flows greater than those measured would have occurred and been sustained for much longer, frequently in excess of 30 days, and flooding associated with high-flow events would have been more severe.

Hydraulic Characteristics of Bedrock Constrictions and Evaluation of One- and Two-Dimensional Models of Flood Flow on the Big Lost River at the Idaho National Engineering and Environmental Laboratory, Idaho

USGS Publications Warehouse

Berenbrock, Charles; Rousseau, Joseph P.; Twining, Brian V.

2007-01-01

A 1.9-mile reach of the Big Lost River, between the Idaho National Engineering and Environmental Laboratory (INEEL) diversion dam and the Pioneer diversion structures, was investigated to evaluate the effects of streambed erosion and bedrock constrictions on model predictions of water-surface elevations. Two one-dimensional (1-D) models, a fixed-bed surface-water flow model (HEC-RAS) and a movable-bed surface-water flow and sediment-transport model (HEC-6), were used to evaluate these effects. The results of these models were compared to the results of a two-dimensional (2-D) fixed-bed model [Transient Inundation 2-Dimensional (TRIM2D)] that had previously been used to predict water-surface elevations for peak flows with sufficient stage and stream power to erode floodplain terrain features (Holocene inset terraces referred to as BLR#6 and BLR#8) dated at 300 to 500 years old, and an unmodified Pleistocene surface (referred to as the saddle area) dated at 10,000 years old; and to extend the period of record at the Big Lost River streamflow-gaging station near Arco for flood-frequency analyses. The extended record was used to estimate the magnitude of the 100-year flood and the magnitude of floods with return periods as long as 10,000 years. In most cases, the fixed-bed TRIM2D model simulated higher water-surface elevations, shallower flow depths, higher flow velocities, and higher stream powers than the fixed-bed HEC-RAS and movable-bed HEC-6 models for the same peak flows. The HEC-RAS model required flow increases of 83 percent [100 to 183 cubic meters per second (m3/s)], and 45 percent (100 to 145 m3/s) to match TRIM2D simulations of water-surface elevations at two paleoindicator sites that were used to determine peak flows (100 m3/s) with an estimated return period of 300 to 500 years; and an increase of 13 percent (150 to 169 m3/s) to match TRIM2D water-surface elevations at the saddle area that was used to establish the peak flow (150 m3/s) of a paleoflood with a return period of 10,000 years. A field survey of the saddle area, however, indicated that the elevation of the lowest point on the saddle area was 1.2 feet higher than indicated on the 2-ft contour map that was used in the TRIM2D model. Because of this elevation discrepancy, HEC-RAS model simulations indicated that a peak flow of at least 210 m3/s would be needed to initiate flow across the 10,000-year old Pleistocene surface. HEC-6 modeling results indicated that to compensate for the effects of streambed scour, additional flow increases would be needed to match HEC-RAS and TRIM2D water-surface elevations along the upper and middle reaches of the river, and to compensate for sediment deposition, a slight decrease in flows would be needed to match HEC-RAS water-surface elevations along the lower reach of the river. Differences in simulated water-surface elevations between the TRIM2D and the HEC-RAS and HEC-6 models are attributed primarily to differences in topographic relief and to differences in the channel and floodplain geometries used in these models. Topographic differences were sufficiently large that it was not possible to isolate the effects of these differences on simulated water-surface elevations from those attributable to the effects of supercritical flow, streambed scour, and sediment deposition.

Adjusted peak-flow frequency estimates for selected streamflow-gaging stations in or near Montana based on data through water year 2011: Chapter D in Montana StreamStats

USGS Publications Warehouse

Sando, Steven K.; Sando, Roy; McCarthy, Peter M.; Dutton, DeAnn M.

2016-04-05

The climatic conditions of the specific time period during which peak-flow data were collected at a given streamflow-gaging station (hereinafter referred to as gaging station) can substantially affect how well the peak-flow frequency (hereinafter referred to as frequency) results represent long-term hydrologic conditions. Differences in the timing of the periods of record can result in substantial inconsistencies in frequency estimates for hydrologically similar gaging stations. Potential for inconsistency increases with decreasing peak-flow record length. The representativeness of the frequency estimates for a short-term gaging station can be adjusted by various methods including weighting the at-site results in association with frequency estimates from regional regression equations (RREs) by using the Weighted Independent Estimates (WIE) program. Also, for gaging stations that cannot be adjusted by using the WIE program because of regulation or drainage areas too large for application of RREs, frequency estimates might be improved by using record extension procedures, including a mixed-station analysis using the maintenance of variance type I (MOVE.1) procedure. The U.S. Geological Survey, in cooperation with the Montana Department of Transportation and the Montana Department of Natural Resources and Conservation, completed a study to provide adjusted frequency estimates for selected gaging stations through water year 2011.The purpose of Chapter D of this Scientific Investigations Report is to present adjusted frequency estimates for 504 selected streamflow-gaging stations in or near Montana based on data through water year 2011. Estimates of peak-flow magnitudes for the 66.7-, 50-, 42.9-, 20-, 10-, 4-, 2-, 1-, 0.5-, and 0.2-percent annual exceedance probabilities are reported. These annual exceedance probabilities correspond to the 1.5-, 2-, 2.33-, 5-, 10-, 25-, 50-, 100-, 200-, and 500-year recurrence intervals, respectively.The at-site frequency estimates were adjusted by weighting with frequency estimates from RREs using the WIE program for 438 selected gaging stations in Montana. These 438 selected gaging stations (1) had periods of record less than or equal to 40 years, (2) represented unregulated or minor regulation conditions, and (3) had drainage areas less than about 2,750 square miles.The weighted-average frequency estimates obtained by weighting with RREs generally are considered to provide improved frequency estimates. In some cases, there are substantial differences among the at-site frequency estimates, the regression-equation frequency estimates, and the weighted-average frequency estimates. In these cases, thoughtful consideration should be applied when selecting the appropriate frequency estimate. Some factors that might be considered when selecting the appropriate frequency estimate include (1) whether the specific gaging station has peak-flow characteristics that distinguish it from most other gaging stations used in developing the RREs for the hydrologic region; and (2) the length of the peak-flow record and the general climatic characteristics during the period when the peak-flow data were collected. For critical structure-design applications, a conservative approach would be to select the higher of the at-site frequency estimate and the weighted-average frequency estimate.The mixed-station MOVE.1 procedure generally was applied in cases where three or more gaging stations were located on the same large river and some of the gaging stations could not be adjusted using the weighted-average method because of regulation or drainage areas too large for application of RREs. The mixed-station MOVE.1 procedure was applied to 66 selected gaging stations on 19 large rivers.The general approach for using mixed-station record extension procedures to adjust at-site frequencies involved (1) determining appropriate base periods for the gaging stations on the large rivers, (2) synthesizing peak-flow data for the gaging stations with incomplete peak-flow records during the base periods by using the mixed-station MOVE.1 procedure, and (3) conducting frequency analysis on the combined recorded and synthesized peak-flow data for each gaging station. Frequency estimates for the combined recorded and synthesized datasets for 66 gaging stations with incomplete peak-flow records during the base periods are presented. The uncertainties in the mixed-station record extension results are difficult to directly quantify; thus, it is important to understand the intended use of the estimated frequencies based on analysis of the combined recorded and synthesized datasets. The estimated frequencies are considered general estimates of frequency relations among gaging stations on the same stream channel that might be expected if the gaging stations had been gaged during the same long-term base period. However, because the mixed-station record extension procedures involve secondary statistical analysis with accompanying errors, the uncertainty of the frequency estimates is larger than would be obtained by collecting systematic records for the same number of years in the base period.

Free jet feasibility study of a thermal acoustic shield concept for AST/VCE application: Dual stream nozzles

NASA Technical Reports Server (NTRS)

Janardan, B. A.; Brausch, J. F.; Majjigi, R. K.

1985-01-01

The influence of selected geometric and aerodynamic flow variables of an unsuppressed coannular plug nozzle and a coannular plug nozzle with a 20-chute outer stream suppressor were experimentally determined. A total of 136 static and simulated flight acoustic test points were conducted with 9 scale model nozzles. Also, aerodynamic measurements of four selected plumes were made with a laser velocimeter. The presence of the 180 deg shield produced different mixing characteristics on the shield side compared to the unshield side because of the reduced mixing with ambient air on the shielded side. This resulted in a stretching of the jet, yielding a higher peak mean velocity up to a length of 10 equivalent diameters from the nozzle exit. The 180 deg shield in community orientation around the suppressed coannular plug nozzle yielded acoustic benefit at all observer angles for a simulated takeoff. While the effect of shield-to-outer stream velocity ratio was small at angles up to 120 deg, beyond this angle significant acoustic benefit was realized with a shield-to-outer stream velocity ratio of 0.64.

Linear growth rates of resistive tearing modes with sub-Alfvénic streaming flow

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

Wu, L. N.; College of Sciences, China Jiliang University, Hangzhou 310018; Ma, Z. W., E-mail: zwma@zju.edu.cn

2014-07-15

The tearing instability with sub-Alfvénic streaming flow along the external magnetic field is investigated using resistive MHD simulation. It is found that the growth rate of the tearing mode instability is larger than that without the streaming flow. With the streaming flow, there exist two Alfvén resonance layers near the central current sheet. The larger perturbation of the magnetic field in two closer Alfvén resonance layers could lead to formation of the observed cone structure and can largely enhance the development of the tearing mode for a narrower streaming flow. For a broader streaming flow, a larger separation of Alfvénmore » resonance layers reduces the magnetic reconnection. The linear growth rate decreases with increase of the streaming flow thickness. The growth rate of the tearing instability also depends on the plasma beta (β). When the streaming flow is embedded in the current sheet, the growth rate increases with β if β < β{sub s}, but decreases if β > β{sub s}. The existence of the specific value β{sub s} can be attributed to competition between the suppressing effect of β and the enhancing effect of the streaming flow on the magnetic reconnection. The critical value β{sub s} increases with increase of the streaming flow strength.« less

Techniques for estimating streamflow characteristics in the Eastern and Interior coal provinces of the United States

USGS Publications Warehouse

Wetzel, Kim L.; Bettandorff, J.M.

1986-01-01

Techniques are presented for estimating various streamflow characteristics, such as peak flows, mean monthly and annual flows, flow durations, and flow volumes, at ungaged sites on unregulated streams in the Eastern Coal region. Streamflow data and basin characteristics for 629 gaging stations were used to develop multiple-linear-regression equations. Separate equations were developed for the Eastern and Interior Coal Provinces. Drainage area is an independent variable common to all equations. Other variables needed, depending on the streamflow characteristic, are mean annual precipitation, mean basin elevation, main channel length, basin storage, main channel slope, and forest cover. A ratio of the observed 50- to 90-percent flow durations was used in the development of relations to estimate low-flow frequencies in the Eastern Coal Province. Relations to estimate low flows in the Interior Coal Province are not presented because the standard errors were greater than 0.7500 log units and were considered to be of poor reliability.

Integrating the pulse of the riverscape and landscape: modelling stream metabolism using continuous dissolved oxygen measurements

NASA Astrophysics Data System (ADS)

Soulsby, C.; Birkel, C.; Malcolm, I.; Tetzlaff, D.

2013-12-01

Stream metabolism is a fundamental pulse of the watershed which reflects both the in-stream environment and its connectivity with the wider landscape. We used high quality, continuous (15 minute), long-term (>3 years) measurement of stream dissolved oxygen (DO) concentrations to estimate photosynthetic productivity (P) and system respiration (R) in forest and moorland reaches of an upland stream with peaty soils. We calibrated a simple five parameter numerical oxygen mass balance model driven by radiation, stream and air temperature, stream depth and re-aeration capacity. This used continuous 24-hour periods for the whole time series to identify behavioural simulations where DO simulations were re-produced sufficiently well to be considered reasonable representations of ecosystem functioning. Results were evaluated using a seasonal Regional Sensitivity Analysis and a co-linearity index for parameter sensitivity. This showed that >95 % of the behavioural models for the moorland and forest sites were identifiable and able to infer in-stream processes from the DO time series for almost half of all measured days at both sites. Days when the model failed to simulate DO levels successfully provided invaluable insight into time periods when other factors are likely to disrupt in-stream metabolic processes; these include (a) flood events when scour reduces the biomass of benthic primary producers, (b) periods of high water colour in higher summer/autumn flows and (c) low flow periods when hyporheic respiration is evident. Monthly P/R ratios <1 indicate a heterotrophic system with both sites exhibiting similar temporal patterns; with a maximum in February and a second peak during summer months. However, the estimated net ecosystem productivity (NPP) suggests that the moorland reach without riparian tree cover is likely to be a much larger source of carbon to the atmosphere (122 mmol C m-2 d-1) compared to the forested reach (64 mmol C m-2 d-1). The study indicates the value of integrating field and modelling studies of stream metabolism as a means of understanding the dynamic interactions of the riverscape and its surrounding landscape.

Influence of observers and stream flow on northern two-lined salamander (Eurycea bislineata bislineata) relative abundance estimates in Acadia and Shenandoah National Parks, USA

USGS Publications Warehouse

Crocker, J.B.; Bank, M.S.; Loftin, C.S.; Jung Brown, R.E.

2007-01-01

We investigated effects of observers and stream flow on Northern Two-Lined Salamander (Eurycea bislineata bislineata) counts in streams in Acadia (ANP) and Shenandoah National Parks (SNP). We counted salamanders in 22 ANP streams during high flow (May to June 2002) and during low flow (July 2002). We also counted salamanders in SNP in nine streams during high flow (summer 2003) and 11 streams during low flow (summers 2001?02, 2004). In 2002, we used a modified cover-controlled active search method with a first and second observer. In succession, observers turned over 100 rocks along five 1-m belt transects across the streambed. The difference between observers in total salamander counts was not significant. We counted fewer E. b. bislineata during high flow conditions, confirming that detection of this species is reduced during high flow periods and that assessment of stream salamander relative abundance is likely more reliable during low or base flow conditions.

Boulder-Faced Log Dams and other Alternatives for Gabion Check Dams in First-Order Ephemeral Streams with Coarse Bed Load in Ethiopia

NASA Astrophysics Data System (ADS)

Nyssen, Jan; Gebreslassie, Seifu; Assefa, Romha; Deckers, Jozef; Guyassa, Etefa; Poesen, Jean; Frankl, Amaury

2017-04-01

Many thousands of gabion check dams have been installed to control gully erosion in Ethiopia, but several challenges still remain, such as the issue of gabion failure in ephemeral streams with coarse bed load, that abrades at the chute step. As an alternative for gabion check dams in torrents with coarse bed load, boulder-faced log dams were conceived, installed transversally across torrents and tested (n = 30). For this, logs (22-35 cm across) were embedded in the banks of torrents, 0.5-1 m above the bed and their upstream sides were faced with boulders (0.3-0.7 m across). Similar to gabion check dams, boulder-faced log dams lead to temporary ponding, spreading of peak flow over the entire channel width and sediment deposition. Results of testing under extreme flow conditions (including two storms with return periods of 5.6 and 7 years) show that 18 dams resisted strong floods. Beyond certain flood thresholds, represented by proxies such as Strahler's stream order, catchment area, D95 or channel width), 11 log dams were completely destroyed. Smallholder farmers see much potential in this type of structure to control first-order torrents with coarse bed load, since the technique is cost-effective and can be easily installed.

Application of the Hydroecological Integrity Assessment Process for Missouri Streams

USGS Publications Warehouse

Kennen, Jonathan G.; Henriksen, James A.; Heasley, John; Cade, Brian S.; Terrell, James W.

2009-01-01

Natural flow regime concepts and theories have established the justification for maintaining or restoring the range of natural hydrologic variability so that physiochemical processes, native biodiversity, and the evolutionary potential of aquatic and riparian assemblages can be sustained. A synthesis of recent research advances in hydroecology, coupled with stream classification using hydroecologically relevant indices, has produced the Hydroecological Integrity Assessment Process (HIP). HIP consists of (1) a regional classification of streams into hydrologic stream types based on flow data from long-term gaging-station records for relatively unmodified streams, (2) an identification of stream-type specific indices that address 11 subcomponents of the flow regime, (3) an ability to establish environmental flow standards, (4) an evaluation of hydrologic alteration, and (5) a capacity to conduct alternative analyses. The process starts with the identification of a hydrologic baseline (reference condition) for selected locations, uses flow data from a stream-gage network, and proceeds to classify streams into hydrologic stream types. Concurrently, the analysis identifies a set of non-redundant and ecologically relevant hydrologic indices for 11 subcomponents of flow for each stream type. Furthermore, regional hydrologic models for synthesizing flow conditions across a region and the development of flow-ecology response relations for each stream type can be added to further enhance the process. The application of HIP to Missouri streams identified five stream types ((1) intermittent, (2) perennial runoff-flashy, (3) perennial runoff-moderate baseflow, (4) perennial groundwater-stable, and (5) perennial groundwater-super stable). Two Missouri-specific computer software programs were developed: (1) a Missouri Hydrologic Assessment Tool (MOHAT) which is used to establish a hydrologic baseline, provide options for setting environmental flow standards, and compare past and proposed hydrologic alterations; and (2) a Missouri Stream Classification Tool (MOSCT) designed for placing previously unclassified streams into one of the five pre-defined stream types.

Controls on streamflow intermittence in the Colorado Front Range

NASA Astrophysics Data System (ADS)

Kampf, S. K.; Puntenney, K.; Martin, C.; Weber, R.; Gerlich, J.; Hammond, J. C.; Lefsky, M. A.

2017-12-01

Intermittent streams comprise more than 60% of the channel length in semiarid northern Colorado, yet little is known about their flow magnitude and timing. We used field surveys, stream sensors, and remote sensing to quantify spatial and temporal patterns of streamflow intermittence in the Cache la Poudre basin in 2016-2017. To evaluate potential controls on streamflow intermittence, we delineated the drainage area to each monitored point and quantified the catchment's mean precipitation, temperature, snow persistence, slope, aspect, vegetation type, soil type, and bedrock geology. During the period of study, most streams below 2500 m elevation and <550 mm mean annual precipitation were intermittent, with flow only during the early spring and summer. In these drier low elevation areas, flow duration generally increased with precipitation and snow persistence. Locally, the type of bedrock geology and location of streams relative to faults affected flow duration. Above 2500 m, nearly all streams with drainage areas >1 km2 had perennial flow, whereas nearly all streams with drainage areas <1 km2 had intermittent flow. For the high elevation intermittent streams, stream locations often differed substantially from the locations mapped in standard GIS data products. Initial analyses have identified no clearly quantifiable controls on flow duration of high elevation streams, but field observations indicate subsurface flow paths are important contributors to surface streams.

Estimating flood hydrographs for urban basins in North Carolina

USGS Publications Warehouse

Mason, R.R.; Bales, J.D.

1996-01-01

A dimensionless hydrograph for North Carolina was developed from data collected in 29 urban and urbanizing basins in the State. The dimen- sionless hydrograph can be used with an estimate of peak flow and basin lagtime to synthesize a design flood hydrograph for urban basins in North Carolina. Peak flows can be estimated from a number of avail- able techniques; a procedure for estimating basin lagtime from main channel length, stream slope, and percentage of impervious area was developed from data collected at 50 sites and is presented in this report. The North Carolina dimensionless hydrograph provides satis- factory predictions of flood hydrographs in all regions of the State except for basins in or near Asheville where the method overestimated 11 of 12 measured hydrographs. A previously developed dimensionless hydrograph for urban basins in the Piedmont and upper Coastal Plain of South Carolina provides better flood-hydrograph predictions for the Asheville basins and has a standard error of 21 percent as compared to 41 percent for the North Carolina dimensionless hydrograph.

Tracing seasonal groundwater contributions to stream flow using a suite of environmental isotopes

NASA Astrophysics Data System (ADS)

Pritchard, J. L.; Herczeg, A. L.; Lamontagne, S.

2003-04-01

Groundwater discharge to streams is important for delivering essential solutes to maintain ecosystem health and flow throughout dry seasons. However, managing the groundwater components of stream flow is difficult because several sources of water can contribute, including delayed drainage from bank storage and regional groundwater. In this study we assessed the potential for a variety of environmental tracers to discriminate between different sources of water to stream flow. A case study comparing Cl-, delta O-18 &delta H-2, Rn-222 and 87Sr/86Sr to investigate the spatial and temporal variability of groundwater inputs to stream flow was conducted in the Wollombi Brook Catchment (SE Australia). The objectives were to characterise the three potential sources of water to stream flow (surface water, groundwater from the near-stream sandy alluvial aquifer system, and groundwater from the regional sandstone aquifer system) and estimate their relative contributions to stream discharge at flood recession and baseflow. Surface water was sampled at various locations along the Wollombi Brook and from its tributaries during flood recession (Mar-01) and under baseflow conditions (Oct-01). Alluvial groundwater was sampled from a piezometer network and regional groundwater from deeper bores in the lower to mid-catchment biannually over two years to characterise these potential sources of water to stream flow. Chloride identified specific reaches of the catchment that were either subjected to evaporation or received regional groundwater contributions to stream flow. The water isotopes verified which of these reaches were dominated by evaporation versus groundwater contributions. They also revealed that the predominant sources of water to stream flow during flood recession were either rainfall and storm runoff or regional groundwater, and that during baseflow the predominant source of water to stream flow was alluvial groundwater. Radon showed that there was a greater proportion of groundwater contributing to stream flow in the upper part of the catchment than the lower catchment during both flood recession and baseflow. Strontium isotopes showed that regional groundwater contributed less than 10% to stream flow in all parts of the catchment under baseflow conditions.

Disk-Anchored Magnetic Propellers - A Cure for the SW Sex Syndrome

NASA Astrophysics Data System (ADS)

Horne, Keith

In AE Aqr, magnetic fields transfer energy and angular momentum from a rapidly-spinning white dwarf to material in the gas stream from the companion star, with the effect of spinning down the white dwarf while flinging the gas stream material out of the binary system. This magnetic propeller produces a host of observable signatures, chief among which are broad, single-peaked, flaring emission lines with phase-shifted orbital kinematics. SW Sex stars have accretion disks, but also broad, single-peaked, phase-shifted emission lines similar to those seen in AE Aqr. We propose that a magnetic propeller similar to that which operates in AE Aqr is also at work in SW Sex stars - and to some extent in all nova-like systems. The propeller is anchored in the inner accretion disk, rather than, or in addition to, the white dwarf. Energy and angular momentum are thereby extracted from the inner disk and transferred to gas-stream material flowing above the disk, which is consequently pitched out of the system. This provides a non-local, dissipationless angular-momentum-extraction mechanism, which should result in cool inner disks with temperature profiles flatter than T propto R^{-3/4}, as observed in eclipse mapping studies of nova-like variables. The disk-anchored magnetic propeller model appears to explain qualitatively most if not all of the peculiar features of the SW Sex syndrome.

Numerical simulation of flows in a circular pipe transversely subjected to a localized impulsive body force with applications to blunt traumatic aortic rupture

NASA Astrophysics Data System (ADS)

Di Labbio, G.; Keshavarz-Motamed, Z.; Kadem, L.

2017-06-01

Much debate surrounds the mechanisms responsible for the occurrence of blunt traumatic aortic rupture in car accidents, particularly on the role of the inertial body force experienced by the blood due to the abrupt deceleration. The isolated influence of such body forces acting on even simple fluid flows is a fundamental problem in fluid dynamics that has not been thoroughly investigated. This study numerically investigates the fundamental physical problem, where the pulsatile flow in a straight circular pipe is subjected to a transverse body force on a localized volume of fluid. The body force is applied as a brief rectangular impulse in three distinct cases, namely during the accelerating, peak, and decelerating phases of the pulsatile flow. A dimensionless number, termed the degree of influence of the body force (Ψ), is devised to quantify the relative strength of the body force over the flow inertia. The impact induces counter-rotating cross-stream vortices at the boundaries of the forced section accompanied by complex secondary flow structures. This secondary flow is found to develop slowest for an impact occurring during an accelerating flow and fastest during a decelerating flow. The peak skewness of the velocity field, however, occurred at successively later times for the three respective cases. After the impact, these secondary flows act to restore the unforced state and such dominant spatial structures are revealed by proper orthogonal decomposition of the velocity field. This work presents a new class of problems that requires further theoretical and experimental investigation.

Seasonal and spatial patterns of metals at a restored copper mine site. I. Stream copper and zinc

USGS Publications Warehouse

Bambic, D.G.; Alpers, Charles N.; Green, P.G.; Fanelli, E.; Silk, W.K.

2006-01-01

Seasonal and spatial variations in metal concentrations and pH were found in a stream at a restored copper mine site located near a massive sulfide deposit in the Foothill copper-zinc belt of the Sierra Nevada, California. At the mouth of the stream, copper concentrations increased and pH decreased with increased streamflow after the onset of winter rain and, unexpectedly, reached extreme values 1 or 2 months after peaks in the seasonal hydrographs. In contrast, aqueous zinc and sulfate concentrations were highest during low-flow periods. Spatial variation was assessed in 400 m of reach encompassing an acidic, metal-laden seep. At this seep, pH remained low (2-3) throughout the year, and copper concentrations were highest. In contrast, the zinc concentrations increased with downstream distance. These spatial patterns were caused by immobilization of copper by hydrous ferric oxides in benthic sediments, coupled with increasing downstream supply of zinc from groundwater seepage.

Model-Invariant Hybrid Computations of Separated Flows for RCA Standard Test Cases

NASA Technical Reports Server (NTRS)

Woodruff, Stephen

2016-01-01

NASA's Revolutionary Computational Aerosciences (RCA) subproject has identified several smooth-body separated flows as standard test cases to emphasize the challenge these flows present for computational methods and their importance to the aerospace community. Results of computations of two of these test cases, the NASA hump and the FAITH experiment, are presented. The computations were performed with the model-invariant hybrid LES-RANS formulation, implemented in the NASA code VULCAN-CFD. The model- invariant formulation employs gradual LES-RANS transitions and compensation for model variation to provide more accurate and efficient hybrid computations. Comparisons revealed that the LES-RANS transitions employed in these computations were sufficiently gradual that the compensating terms were unnecessary. Agreement with experiment was achieved only after reducing the turbulent viscosity to mitigate the effect of numerical dissipation. The stream-wise evolution of peak Reynolds shear stress was employed as a measure of turbulence dynamics in separated flows useful for evaluating computations.

Hydraulic characteristics near streamside structures along the Kenai River, Alaska

USGS Publications Warehouse

Dorava, Joseph M.

1995-01-01

Hydraulic characteristics, water velocity, depth, and flow direction were measured near eight sites along the Kenai River in southcentral Alaska. Each of the eight sites contained a different type of structure: a road-type boat launch, a canal-type boat launch, a floating dock, a rock retaining wall, a pile-supported dock, a jetty, a concrete retaining wall, and a bank stabilization project near the city of Soldotna. Measurements of hydraulic characteristics were made to determine to what extent the structures affected natural or ambient stream hydraulic characteristics. The results will be used by the Alaska Department of Fish and Game to evaluate assumptions used in their Habitat Evaluation Procedure assessment of juvenile chinook salmon habitat along the river and to improve their understanding of stream hydraulics for use in permitting potential projects. The study included structures along the Kenai River from about 12 to 42 miles upstream from the mouth. Hydraulic characteristics were measured during medium-, high-, and low-flow conditions, as measured at the Kenai River at Soldotna: (1) discharge ranged from 6,310 to 6,480 cubic feet per second during medium flow conditions that were near mean annual flow on June 9-10, 1994; (2) discharge ranged from 14,000 to 14,400 cubic feet per second during high flow conditions that were near peak annual flow conditions on August 2-3, 1994; and (3) discharge ranged from 3,470 to 3,660 cubic feet per second during open-water low-flow conditions on May 8-9, 1995. Measurements made at the structures were compared with measurements made at nearby unaffected natural sites. The floating dock, pile-supported dock, road-type boat launch, and concrete retaining wall did not significantly alter the stream channel area. These structures contributed only hydraulic-roughness type changes. The structures occupied a much smaller area than that of the wetted perimeter of the channel and thus typically had little effect on velocity, depth, or flow direction. During this investigation, many of these subtle effects could not be separated from ambient hydraulic conditions. The jetty significantly altered stream channel area and therefore affected stream hydraulics more than the other structures that were investigated. Data indicated that velocity increased from 1.9 to 5.8 feet per second near the point of the jetty during measurements in May, June, and August. Rock wall and jetty structures also divert flow away from near-shore areas in proportion to their projection lengths into the river. For the jetty, the effect on surface flow was observed downstream for a distance of about 10 times the length of the jetty's projection into the river and upstream for about 4 to 5 times the length of the projection. For the rock wall, the diversion of flow was evident for 10 to 15 feet downstream.

Beaded streams of Arctic permafrost landscapes

NASA Astrophysics Data System (ADS)

Arp, C. D.; Whitman, M. S.; Jones, B. M.; Grosse, G.; Gaglioti, B. V.; Heim, K. C.

2014-07-01

Beaded streams are widespread in permafrost regions and are considered a common thermokarst landform. However, little is known about their distribution, how and under what conditions they form, and how their intriguing morphology translates to ecosystem functions and habitat. Here we report on a Circum-Arctic inventory of beaded streams and a watershed-scale analysis in northern Alaska using remote sensing and field studies. We mapped over 400 channel networks with beaded morphology throughout the continuous permafrost zone of northern Alaska, Canada, and Russia and found the highest abundance associated with medium- to high-ice content permafrost in moderately sloping terrain. In the Fish Creek watershed, beaded streams accounted for half of the drainage density, occurring primarily as low-order channels initiating from lakes and drained lake basins. Beaded streams predictably transition to alluvial channels with increasing drainage area and decreasing channel slope, although this transition is modified by local controls on water and sediment delivery. Comparison of one beaded channel using repeat photography between 1948 and 2013 indicate relatively stable form and 14C dating of basal sediments suggest channel formation may be as early as the Pleistocene-Holocene transition. Contemporary processes, such as deep snow accumulation in stream gulches effectively insulates river ice and allows for perennial liquid water below most beaded stream pools. Because of this, mean annual temperatures in pool beds are greater than 2 °C, leading to the development of perennial thaw bulbs or taliks underlying these thermokarst features. In the summer, some pools stratify thermally, which reduces permafrost thaw and maintains coldwater habitats. Snowmelt generated peak-flows decrease rapidly by two or more orders of magnitude to summer low flows with slow reach-scale velocity distributions ranging from 0.1 to 0.01 m s-1, yet channel runs still move water rapidly between pools. This repeating spatial pattern associated with beaded stream morphology and hydrological dynamics may provide abundant and optimal foraging habitat for fish. Thus, beaded streams may create important ecosystem functions and habitat in many permafrost landscapes and their distribution and dynamics are only beginning to be recognized in Arctic research.

The prediction of noise and installation effects of high-subsonic dual-stream jets in flight

NASA Astrophysics Data System (ADS)

Saxena, Swati

Both military and civil aircraft in service generate high levels of noise. One of the major contributors to this noise generated from the aircraft is the jet engine exhaust. This makes the study of jet noise and methods to reduce jet noise an active research area with the aim of designing quieter military and commercial aircraft. The current stringent aircraft noise regulations imposed by the Federal Aviation Administration (FAA) and other international agencies, have further raised the need to perform accurate jet noise calculations for more reliable estimation of the jet noise sources. The main aim of the present research is to perform jet noise simulations of single and dual-stream jets with engineering accuracy and assess forward flight effects on the jet noise. Installation effects such as caused by the pylon are also studied using a simplified pylon nozzle configuration. Due to advances in computational power, it has become possible to perform turbulent flow simulations of high speed jets, which leads to more accurate noise predictions. In the present research, a hybrid unsteady RANS-LES parallel multi-block structured grid solver called EAGLEJet is written to perform the nozzle flow calculations. The far-field noise calculation is performed using solutions to the Ffowcs Williams and Hawkings equation. The present calculations use meshes with 5 to 11 million grid points and require about three weeks of computing time with about 100 processors. A baseline single stream convergent nozzle and a dual-stream coaxial convergent nozzle are used for the flow and noise analysis. Calculations for the convergent nozzle are performed at a high subsonic jet Mach number of Mj = 0.9, which is similar to the operating conditions for commercial aircraft engines. A parallel flow gives the flight effect, which is simulated with a co-flow Mach number, Mcf varying from 0.0 to 0.28. The grid resolution effects, statistical properties of the turbulence and the heated jet effects ( TTR = 2.7) are studied and related to the noise characteristics of the jet. Both flow and noise predictions show good agreement with PIV and microphone measurements. The potential core lengths and nozzle wall boundary characteristics are studied to understand the differences between the numerical potential core lengths as compared to experiments. The flight velocity exponent, m is calculated from the noise reduction in overall sound pressure levels (OASPL, dB) and relative velocity (V j -- Vcf) at all jet inlet (angular) angles. The variation of the exponent, m at lower (50° to 90°) and higher aft inlet angles (120° to 150°) is studied and compared with available measurements. Previous studies have shown a different variation of the exponent with inlet angles while the current numerical data match well with recent experiments conducted on the same nozzle geometry. Today, turbofans are the most efficient engines in service used in almost all major commercial aircraft. Turbofans have a dual-stream exhaust nozzle with primary and secondary flow whose flow and noise characteristics are different from that of single stream jets. A Boeing-designed coaxial nozzle, with area ratio of As/Ap = 3.0, is used to study dual-stream jet noise in the present research. In this configuration, the primary nozzle extends beyond the secondary nozzle, which is representative of large turbofan engines in commercial service. The flow calculations are performed at high subsonic Mach numbers in the primary and secondary nozzles (Mpj = 0.85, Msj = 0.95) with heated core flow, TTRp = 2.26 and unheated fan flow, TTRs = 1.0. The co-flow of Mcf = 0.2 is used. The subscript p, s and amb represent the primary (core) nozzle, the secondary (fan) nozzle, and the ambient flow conditions, respectively. The statistical properties in the primary and secondary shear layers are studied and compared with those of the single stream jets. It has been found that the eddy convection velocity is lower in dual-stream jets as compared to the single stream jet operating at a similar jet exit Mach number. The phase velocity is higher in the secondary shear layer as compared to primary shear layer. The noise measurements agree well with the predicted data and noise reduction is observed in the presence of co-flow. The variation of the flight velocity exponent is calculated as a function of nozzle inlet angle. The value of the exponent at higher inlet angles is lower as compared to the single stream jets. This suggests that the noise levels are less affected in the peak noise direction in the presence of co-flow in dual-stream jets as compared to single stream jets. Two reference velocities: primary jet exit velocity Vpj and mixed velocity Vmix are considered which result in different absolute values of the exponents. Scaling of the jet spectra is performed at different inlet angles and good collapse has been obtained between the spectra. The installation effects on jet noise are studied using a simplified pylon structure with a dual-stream nozzle. In the presence of a pylon, the azimuthal symmetry of the nozzle is lost and thus the flow characteristics are different as compared to the baseline nozzle. This will result in different noise characteristics of the installed jet.

Energetics of the Brazil Current in the Rio Grande Cone region

NASA Astrophysics Data System (ADS)

Brum, André Lopes; Azevedo, José Luiz Lima de; Oliveira, Leopoldo Rota de; Calil, Paulo Henrique Rezende

2017-10-01

The energetics of the Brazil Current (BC) in the region of the Rio Grande Cone (RGC, 30-35.5°S), a topographic rise in the southwest portion of the Brazilian continental margin, are analyzed using 16 years of numerical data from the Ocean General Circulation Model (OGCM) for the Earth Simulator (OFES). The main focus of this study is the eddy-mean flow interactions of the BC and the local energy budgets in the study region. The kinetic and potential energy balance equations are derived for mean and eddy flows, and the resulting terms are presented and discussed. The eddy-mean flow interactions exhibit complex spatial distributions, and the intensities of the energy budgets decrease with increasing depth. However, only the mean potential energy (MPE) budget decreases southward. Eddy kinetic energy (EKE) and eddy potential energy (EPE) exhibit similar horizontal distribution patterns. Additionally, the baroclinic and barotropic conversion rates increase downstream of the bump, where the eddy energy field exhibits along-stream variability that increases southward. Barotropic conversion is more intense between 50 and 200 m, where mean kinetic energy (MKE) and EKE are concentrated, and it exhibits a horizontal cross-stream variation pattern, with mean-to-eddy energy conversion observed on the offshore side of the BC. This result indicates that the turbulence associated with the stream jet increases as the BC moves away from the coast, with the conversion term acting to stabilize the flow. Baroclinic conversion exhibits a high intensity below 300 m (where MPE and EPE display peaks), and it has a greater influence on the eddy-mean flow interaction than does the barotropic conversion. The RGC directly affects the local dynamics of the BC by increasing the eddy field as soon as the BC reaches the bump. The energy diagrams illustrate a stream characterized by evolving barotropic and baroclinic instability processes throughout the water column. This result indicates an intrinsically unstable jet in the study region. Moreover, baroclinic instability is the main source of EKE in the RGC region.

Recent (2003-05) water quality of Barton Springs, Austin, Texas, with emphasis on factors affecting variability

USGS Publications Warehouse

Mahler, Barbara J.; Garner, Bradley D.; Musgrove, MaryLynn; Guilfoyle, Amber L.; Rao, Mohan V.

2006-01-01

From 2003 to 2005, the U.S. Geological Survey, in cooperation with the Texas Commission on Environmental Quality, collected and analyzed water samples from the four springs (orifices) of Barton Springs in Austin, Texas (Upper, Main, Eliza, and Old Mill Springs), with the objective of characterizing water quality. Barton Springs is the major discharge point for the Barton Springs segment of the Edwards aquifer. A three-pronged sampling approach was used: physicochemical properties (including specific conductance and turbidity) were measured continuously; samples were collected from the four springs routinely every 2 weeks (during August-September 2003) to 3 weeks (during June 2004-June 2005) and analyzed for some or all major ions, nutrients, trace elements, soluble pesticides, and volatile organic compounds; and samples were collected from the four springs at more closely spaced intervals during the 2 weeks following two storms and analyzed for the same suite of constituents. Following the two storms, samples also were collected from five of the six major streams that provide recharge to Barton Springs. Spring discharge during both sample collection periods was above average (60 cubic feet per second or greater). Barton Springs was found to be affected by persistent low concentrations of atrazine (an herbicide), chloroform (a drinking-water disinfection by-product), and tetrachloroethene (a solvent). Increased recharge from the major recharging streams resulted in increased calcium, sulfate, atrazine, simazine, and tetrachloroethene concentrations and decreased concentrations of most other major ions, nitrate, and chloroform at one or more of the springs. These changes in concentration demonstrate the influence of water quality in recharging streams on water quality at the springs even during non-stormflow conditions. The geochemical compositions of the four springs indicate that Upper Spring is more contaminated and is influenced by a contributing flow path that is separate from those leading to other springs under all but stormflow conditions. Main, Eliza, and Old Mill Springs share at least one common flow path that contributes contaminants to the three springs. Old Mill Spring, however, is less affected by anthropogenic contaminants than the other springs and receives a greater component of water from a flow path whose geochemistry is influenced by water from the saline zone of the aquifer. At Main Spring, atrazine, simazine, chloroform, and tetrachloroethene concentrations increased following storms, describing breakthrough curves that peaked 2 days following rainfall; at Upper Spring, atrazine and simazine concentrations described breakthrough curves that peaked 1 day following rainfall. At both Main and Upper Springs, additional anthropogenic compounds were detected following storms. The geochemical response of the springs to recharge indicates that much of the transport occurs through conduits. When there is no flow in the recharging streams, ground water advects from the aquifer matrix into the conduits and is transported to the springs. When there is flow in the streams, recharge through the streambeds directly enters the conduit system and is transported to the springs. Following storms, surface runoff recharges through both interstream recharge features and streambeds, delivering runoff-related contaminants to Barton Springs.

Roughness, resistance, and dispersion: Relationships in small streams

NASA Astrophysics Data System (ADS)

Noss, Christian; Lorke, Andreas

2016-04-01

Although relationships between roughness, flow, and transport processes in rivers and streams have been investigated for several decades, the prediction of flow resistance and longitudinal dispersion in small streams is still challenging. Major uncertainties in existing approaches for quantifying flow resistance and longitudinal dispersion at the reach scale arise from limitations in the characterization of riverbed roughness. In this study, we characterized the riverbed roughness in small moderate-gradient streams (0.1-0.5% bed slope) and investigated its effects on flow resistance and dispersion. We analyzed high-resolution transect-based measurements of stream depth and width, which resolved the complete roughness spectrum with scales ranging from the micro to the reach scale. Independently measured flow resistance and dispersion coefficients were mainly affected by roughness at spatial scales between the median grain size and the stream width, i.e., by roughness between the micro- and the mesoscale. We also compared our flow resistance measurements with calculations using various flow resistance equations. Flow resistance in our study streams was well approximated by the equations that were developed for high gradient streams (>1%) and it was overestimated by approaches developed for sand-bed streams with a smooth riverbed or ripple bed. This article was corrected on 10 MAY 2016. See the end of the full text for details.

Strong wave/mean-flow coupling in baroclinic acoustic streaming

NASA Astrophysics Data System (ADS)

Chini, Greg; Michel, Guillaume

2017-11-01

Recently, Chini et al. demonstrated the potential for large-amplitude acoustic streaming in compressible channel flows subjected to strong background cross-channel density variations. In contrast with classic Rayleigh streaming, standing acoustic waves of O (ɛ) amplitude acquire vorticity owing to baroclinic torques acting throughout the domain rather than via viscous torques acting in Stokes boundary layers. More significantly, these baroclinically-driven streaming flows have a magnitude that also is O (ɛ) , i.e. comparable to that of the sound waves. In the present study, the consequent potential for fully two-way coupling between the waves and streaming flows is investigated using a novel WKBJ analysis. The analysis confirms that the wave-driven streaming flows are sufficiently strong to modify the background density gradient, thereby modifying the leading-order acoustic wave structure. Simulations of the wave/mean-flow system enabled by the WKBJ analysis are performed to illustrate the nature of the two-way coupling, which contrasts sharply with classic Rayleigh streaming, for which the waves can first be determined and the streaming flows subsequently computed.

Hysteretic behavior of stage-discharge relationships in urban streams

NASA Astrophysics Data System (ADS)

Miller, A. J.; Lindner, G. A.

2009-12-01

Reliable stage-discharge relationships or rating curves are of critical importance for accurate calculation of streamflow and maintenance of long-term flow records. Urban streams offer particular challenges for the maintenance of accurate rating curves. It is often difficult or impossible to collect direct discharge measurements at high flows, many of which are generated by short-duration high-intensity summer thunderstorms, both because of dangerous conditions in the channel and also because the stream rises and falls so rapidly that field crews cannot reach sites in time and sometimes cannot make measurements rapidly enough to keep pace with changing water levels even when they are on site during a storm. Work in urban streams in the Baltimore metropolitan area has shown that projection of rating curves beyond the range of measured flows can lead to overestimation of flood peaks by as much as 100%, and these can only be corrected when adequate field data are available to support modeling efforts. Even moderate flows that are above safe wading depth and velocity may best be estimated using hydraulic models. Current research for NSF CNH project 0709659 includes the application of 2-d depth-averaged hydraulic models to match existing rating curves over a range of low to moderate flows and to extend rating curves for higher flows, based on field collection of high-water marks. Although it is generally assumed that stage-discharge relationships are single-valued, we find that modeling results in small urban streams often generate hysteretic relationships, with higher discharges on the rising limb of the hydrograph than on the falling limb. The difference between discharges for the same stage on the rising and falling limb can be on the order of 20-30% even for in-channel flows that are less than 1 m deep. As safety considerations dictate that it is preferable to make direct discharge measurements on the falling limb of the hydrograph, the higher direct measurements used in many rating curves probably have been collected on the falling limb and therefore may not capture the correct stage-discharge relationship for the rising limb. In some cases model results selected only from the falling limb are able to match the existing rating curve very closely. Although hysteresis may be explained with reference to the innate properties of the flood wave, other factors also lead to hysteretic behavior. Downstream constrictions and obstructions associated with urban infrastructure may cause substantial backwater effects, particularly during flood flows. Flood conditions at tributary confluences also can exert a controlling influence upstream. Based on our results we recommend that at some sites it is advisable to develop separate rating curves for the rising and falling limbs, and to develop a range of modeling scenarios for predicting the range of potential uncertainty.

Estimation of snow and glacier melt contribution to Liddar stream in a mountainous catchment, western Himalaya: an isotopic approach.

PubMed

Jeelani, Gh; Shah, Rouf A; Jacob, Noble; Deshpande, Rajendrakumar D

2017-03-01

Snow- and glacier-dominated catchments in the Himalayas are important sources of fresh water to more than one billion people. However, the contribution of snowmelt and glacier melt to stream flow remains largely unquantified in most parts of the Himalayas. We used environmental isotopes and geochemical tracers to determine the source water and flow paths of stream flow draining the snow- and glacier-dominated mountainous catchment of the western Himalaya. The study suggested that the stream flow in the spring season is dominated by the snowmelt released from low altitudes and becomes isotopically depleted as the melt season progressed. The tracer-based mixing models suggested that snowmelt contributed a significant proportion (5-66 %) to stream flow throughout the year with the maximum contribution in spring and summer seasons (from March to July). In 2013 a large and persistent snowpack contributed significantly (∼51 %) to stream flow in autumn (September and October) as well. The average annual contribution of glacier melt to stream flow is little (5 %). However, the monthly contribution of glacier melt to stream flow reaches up to 19 % in September during years of less persistent snow pack.

Documentation of a computer program to simulate stream-aquifer relations using a modular, finite-difference, ground-water flow model

USGS Publications Warehouse

Prudic, David E.

1989-01-01

Computer models are widely used to simulate groundwater flow for evaluating and managing the groundwater resource of many aquifers, but few are designed to also account for surface flow in streams. A computer program was written for use in the US Geological Survey modular finite difference groundwater flow model to account for the amount of flow in streams and to simulate the interaction between surface streams and groundwater. The new program is called the Streamflow-Routing Package. The Streamflow-Routing Package is not a true surface water flow model, but rather is an accounting program that tracks the flow in one or more streams which interact with groundwater. The program limits the amount of groundwater recharge to the available streamflow. It permits two or more streams to merge into one with flow in the merged stream equal to the sum of the tributary flows. The program also permits diversions from streams. The groundwater flow model with the Streamflow-Routing Package has an advantage over the analytical solution in simulating the interaction between aquifer and stream because it can be used to simulate complex systems that cannot be readily solved analytically. The Streamflow-Routing Package does not include a time function for streamflow but rather streamflow entering the modeled area is assumed to be instantly available to downstream reaches during each time period. This assumption is generally reasonable because of the relatively slow rate of groundwater flow. Another assumption is that leakage between streams and aquifers is instantaneous. This assumption may not be reasonable if the streams and aquifers are separated by a thick unsaturated zone. Documentation of the Streamflow-Routing Package includes data input instructions; flow charts, narratives, and listings of the computer program for each of four modules; and input data sets and printed results for two test problems, and one example problem. (Lantz-PTT)

Fractionating power and outlet stream polydispersity in asymmetrical flow field-flow fractionation. Part I: isocratic operation.

PubMed

Williams, P Stephen

2016-05-01

Asymmetrical flow field-flow fractionation (As-FlFFF) has become the most commonly used of the field-flow fractionation techniques. However, because of the interdependence of the channel flow and the cross flow through the accumulation wall, it is the most difficult of the techniques to optimize, particularly for programmed cross flow operation. For the analysis of polydisperse samples, the optimization should ideally be guided by the predicted fractionating power. Many experimentalists, however, neglect fractionating power and rely on light scattering detection simply to confirm apparent selectivity across the breadth of the eluted peak. The size information returned by the light scattering software is assumed to dispense with any reliance on theory to predict retention, and any departure of theoretical predictions from experimental observations is therefore considered of no importance. Separation depends on efficiency as well as selectivity, however, and efficiency can be a strong function of retention. The fractionation of a polydisperse sample by field-flow fractionation never provides a perfectly separated series of monodisperse fractions at the channel outlet. The outlet stream has some residual polydispersity, and it will be shown in this manuscript that the residual polydispersity is inversely related to the fractionating power. Due to the strong dependence of light scattering intensity and its angular distribution on the size of the scattering species, the outlet polydispersity must be minimized if reliable size data are to be obtained from the light scattering detector signal. It is shown that light scattering detection should be used with careful control of fractionating power to obtain optimized analysis of polydisperse samples. Part I is concerned with isocratic operation of As-FlFFF, and part II with programmed operation.

Estimation of traveltime and longitudinal dispersion in streams in West Virginia

USGS Publications Warehouse

Wiley, Jeffrey B.; Messinger, Terence

2013-01-01

Traveltime and dispersion data are important for understanding and responding to spills of contaminants in waterways. The U.S. Geological Survey (USGS), in cooperation with West Virginia Bureau for Public Health, Office of Environmental Health Services, compiled and evaluated traveltime and longitudinal dispersion data representative of many West Virginia waterways. Traveltime and dispersion data were not available for streams in the northwestern part of the State. Compiled data were compared with estimates determined from national equations previously published by the USGS. The evaluation summarized procedures and examples for estimating traveltime and dispersion on streams in West Virginia. National equations developed by the USGS can be used to predict traveltime and dispersion for streams located in West Virginia, but the predictions will be less accurate than those made with graphical interpolation between measurements. National equations for peak concentration, velocity of the peak concentration, and traveltime of the leading edge had root mean square errors (RMSE) of 0.426 log units (127 percent), 0.505 feet per second (ft/s), and 3.78 hours (h). West Virginia data fit the national equations for peak concentration, velocity of the peak concentration, and traveltime of the leading edge with RMSE of 0.139 log units (38 percent), 0.630 ft/s, and 3.38 h, respectively. The national equation for maximum possible velocity of the peak concentration exceeded 99 percent and 100 percent of observed values from the national data set and West Virginia-only data set, respectively. No RMSE was reported for time of passage of a dye cloud, as estimated using the national equation; however, the estimates made using the national equations had a root mean square error of 3.82 h when compared to data gathered for this study. Traveltime and dispersion estimates can be made from the plots of traveltime as a function of streamflow and location for streams with plots available, but estimates can be made using the national equations for streams without plots. The estimating procedures are not valid for regulated stream reaches that were not individually studied or streamflows outside the limits studied. Rapidly changing streamflow and inadequate mixing across the stream channel affect traveltime and dispersion, and reduce the accuracy of estimates. Increases in streamflow typically result in decreases in the peak concentration and traveltime of the peak concentration. Decreases in streamflow typically result in increases in the peak concentration and traveltime of the peak concentration. Traveltimes will likely be less than those determined using the estimating equations and procedures if the spill is in the center of the stream, and traveltimes will likely be greater than those determined using the estimating equations and procedures if the spill is near the streambank.

Evaluating Titan2D mass-flow model using the 1963 Little Tahoma Peak avalanches, Mount Rainier, Washington

NASA Astrophysics Data System (ADS)

Sheridan, M. F.; Stinton, A. J.; Patra, A.; Pitman, E. B.; Bauer, A.; Nichita, C. C.

2005-01-01

The Titan2D geophysical mass-flow model is evaluated by comparing its simulation results and those obtained from another flow model, FLOW3D, with published data on the 1963 Little Tahoma Peak avalanches on Mount Rainier, Washington. The avalanches, totaling approximately 10×10 6 m 3 of broken lava blocks and other debris, traveled 6.8 km horizontally and fell 1.8 km vertically ( H/ L=0.246). Velocities calculated from runup range from 24 to 42 m/s and may have been as high as 130 m/s while the avalanches passed over Emmons Glacier. Titan2D is a code for an incompressible Coulomb continuum; it is a depth-averaged, 'shallow-water', granular-flow model. The conservation equations for mass and momentum are solved with a Coulomb-type friction term at the basal interface. The governing equations are solved on multiple processors using a parallel, adaptive mesh, Godunov scheme. Adaptive gridding dynamically concentrates computing power in regions of special interest; mesh refinement and coarsening key on the perimeter of the moving avalanche. The model flow initiates as a pile defined as an ellipsoid by a height ( z) and an elliptical base defined by radii in the x and y planes. Flow parameters are the internal friction angle and bed friction angle. Results from the model are similar in terms of velocity history, lateral spreading, location of runup areas, and final distribution of the Little Tahoma Peak deposit. The avalanches passed over the Emmons Glacier along their upper flow paths, but lower in the valley they traversed stream gravels and glacial outwash deposits. This presents difficulty in assigning an appropriate bed friction angle for the entire deposit. Incorporation of variable bed friction angles into the model using GIS will help to resolve this issue.

The effects of green infrastructure on exceedance of critical shear stress in Blunn Creek watershed

NASA Astrophysics Data System (ADS)

Shannak, Sa'd.

2017-10-01

Green infrastructure (GI) has attracted city planners and watershed management professional as a new approach to control urban stormwater runoff. Several regulatory enforcements of GI implementation created an urgent need for quantitative information on GI practice effectiveness, namely for sediment and stream erosion. This study aims at investigating the capability and performance of GI in reducing stream bank erosion in the Blackland Prairie ecosystem. To achieve the goal of this study, we developed a methodology to represent two types of GI (bioretention and permeable pavement) into the Soil Water Assessment Tool, we also evaluated the shear stress and excess shear stress for stream flows in conjunction with different levels of adoption of GI, and estimated potential stream bank erosion for different median soil particle sizes using real and design storms. The results provided various configurations of GI schemes in reducing the negative impact of urban stormwater runoff on stream banks. Results showed that combining permeable pavement and bioretention resulted in the greatest reduction in runoff volumes, peak flows, and excess shear stress under both real and design storms. Bioretention as a stand-alone resulted in the second greatest reduction, while the installation of detention pond only had the least reduction percentages. Lastly, results showed that the soil particle with median diameter equals to 64 mm (small cobbles) had the least excess shear stress across all design storms, while 0.5 mm (medium sand) soil particle size had the largest magnitude of excess shear stress. The current study provides several insights into a watershed scale for GI planning and watershed management to effectively reduce the negative impact of urban stormwater runoff and control streambank erosion.

Using macroinvertebrate assemblages and multiple stressors to infer urban stream system condition: A case study in the central US

USGS Publications Warehouse

Nichols, John W.; Hubbart, Jason A.; Poulton, Barry C.

2016-01-01

Characterizing the impacts of hydrologic alterations, pollutants, and habitat degradation on macroinvertebrate species assemblages is of critical value for managers wishing to categorize stream ecosystem condition. A combination of approaches including trait-based metrics and traditional bioassessments provides greater information, particularly in anthropogenic stream ecosystems where traditional approaches can be confounded by variously interacting land use impacts. Macroinvertebrates were collected from two rural and three urban nested study sites in central Missouri, USA during the spring and fall seasons of 2011. Land use responses of conventional taxonomic and trait-based metrics were compared to streamflow indices, physical habitat metrics, and water quality indices. Results show that biotic index was significantly different (p < 0.05) between sites with differences detected in 54 % of trait-based metrics. The most consistent response to urbanization was observed in size metrics, with significantly (p < 0.05) fewer small bodied organisms. Increases in fine streambed sediment, decreased submerged woody rootmats, significantly higher winter Chloride concentrations, and decreased mean suspended sediment particle size in lower urban stream reaches also influenced macroinvertebrate assemblages. Riffle habitats in urban reaches contained 21 % more (p = 0.03) multivoltine organisms, which was positively correlated to the magnitude of peak flows (r2 = 0.91, p = 0.012) suggesting that high flow events may serve as a disturbance in those areas. Results support the use of macroinvertebrate assemblages and multiple stressors to characterize urban stream system condition and highlight the need to better understand the complex interactions of trait-based metrics and anthropogenic aquatic ecosystem stressors.

Regionalization of winter low-flow characteristics of Tennessee streams

USGS Publications Warehouse

Bingham, R.H.

1986-01-01

Procedures were developed for estimating winter (December-April) low flows at ungaged stream sites in Tennessee based on surface geology and drainage area size. One set of equations applies to West Tennessee streams, and another set applies to Middle and East Tennessee streams. The equations do not apply to streams where flow is significantly altered by the activities of man. Standard errors of estimate of equations for West Tennessee are 22% - 35% and for middle and East Tennessee 31% - 36%. Statistical analyses indicate that summer low-flow characteristics are the same as annual low-flow characteristics, and that winter low flows are larger than annual low flows. Streamflow-recession indexes, in days per log cycle of decrease in discharge, were used to account for effects of geology on low flow of streams. The indexes in Tennessee range from 32 days/log cycle for clay and shale to 350 days/log cycle for gravel and sand, indicating different aquifer characteristics of the geologic units that contribute to streamflows during periods of no surface runoff. Streamflow-recession rate depends primarily on transmissivity and storage characteristics of the aquifers, and the average distance from stream channels to basin divides. Geology and drainage basin size are the most significant variables affecting low flow in Tennessee streams according to regression analyses. (Author 's abstract)

Determining the effects of dams on subdaily variation in river flows at a whole-basin scale

USGS Publications Warehouse

Zimmerman, J.K.H.; Letcher, B.H.; Nislow, K.H.; Lutz, K.A.; Magilligan, F.J.

2010-01-01

River regulation can alter the frequency and magnitude of subdaily flow variations causing major impacts on ecological structure and function. We developed an approach to quantify subdaily flow variation for multiple sites across a large watershed to assess the potential impacts of different dam operations (flood control, run-of-river hydropower and peaking hydropower) on natural communities. We used hourly flow data over a 9-year period from 30 stream gages throughout the Connecticut River basin to calculate four metrics of subdaily flow variation and to compare sites downstream of dams with unregulated sites. Our objectives were to (1) determine the temporal scale of data needed to characterize subdaily variability; (2) compare the frequency of days with high subdaily flow variation downstream of dams and unregulated sites; (3) analyse the magnitude of subdaily variation at all sites and (4) identify individual sites that had subdaily variation significantly higher than unregulated locations. We found that estimates of flow variability based on daily mean flow data were not sufficient to characterize subdaily flow patterns. Alteration of subdaily flows was evident in the number of days natural ranges of variability were exceeded, rather than in the magnitude of subdaily variation, suggesting that all rivers may exhibit highly variable subdaily flows, but altered rivers exhibit this variability more frequently. Peaking hydropower facilities had the most highly altered subdaily flows; however, we observed significantly altered ranges of subdaily variability downstream of some flood-control and run-of-river hydropower dams. Our analysis can be used to identify situations where dam operating procedures could be modified to reduce the level of hydrologic alteration. ?? 2009 John Wiley & Sons, Ltd.

Using stable isotopes to identify the scaling effects of riparian peatlands on runoff generation processes and DOC mobilisation

NASA Astrophysics Data System (ADS)

Tunaley, Claire; Tetzlaff, Doerthe; Soulsby, Chris

2017-04-01

Knowledge of hydrological sources, flow paths, and their connectivity is fundamental to understanding stream flow generation and surface water quality in peatlands. Stable isotopes are proven tools for tracking the sources and flow paths of runoff. However, relativity few studies have used isotopes in peat-dominated catchments. Here, we combined 13 months (June 2014 - July 2015) of daily isotope measurements in stream water with daily DOC and 15 minute FDOM (fluorescent component of dissolved organic matter) data, at three nested scales in NE Scotland, to identify the hydrological processes occurring in riparian peatlands. We investigated how runoff generation processes in a small, riparian peatland dominated headwater catchment (0.65 km2) propagate to larger scales (3.2 km2 and 31 km2) with decreasing percentage of riparian peatland coverage. Isotope damping was most pronounced in the 0.65 km2 catchment due to high water storage in the organic soils which encouraged tracer mixing and resulted in attenuated runoff peaks. At the largest scale, stream flow and water isotope dynamics showed a more flashy response. Particularly insightful in this study was calculating the deviation of the isotopes from the local meteoric water line, the lc-excess. The lc-excess revealed evaporative fractionation in the peatland dominated catchment, particularly during summer low flows. This implied high hydrological connectivity in the form of constant seepage from the peatlands sustaining high baseflows at the headwater scale. This constant connectivity resulted in high DOC concentrations at the peatland site during baseflow ( 5 mg l-1). In contrast, at the larger scales, DOC was minimal during low flows ( 2 mg l-1) due to increased groundwater influence and the disconnection between DOC sources and the stream. Insights into event dynamics through the analysis of DOC hysteresis loops showed slight dilution on the rising limb, the strong influence of dry antecedent conditions and a quick recovery between events at the riparian peatland site. Again, these dynamics were driven by the tight coupling and high connectivity of the landscape to the stream. At larger scales, the disconnection between the landscape units increased and the variable connectivity controlled runoff generation and DOC dynamics. The results presented here suggest that the hydrological processes occurring in riparian peatlands in headwater catchments are less evident at larger scales which may have implications for the larger scale impact of peatland restoration projects.

Time of travel and dispersion of solutes in a 36.4-mile reach of the North Platte River downstream from Casper, Wyoming

USGS Publications Warehouse

Armentrout, G.W.; Larson, L.R.

1984-01-01

Time-of-travel and dispersion measurements made during a dye study November 7-8, 1978, are presented for a reach of the North Platte River from Casper, Wyo., to a bridge 2 miles downstream from below the Dave Johnston Power Plant. Rhodamine WT dye was injected into the river at Casper, and the resultant dye cloud was traced by sampling as it moved downstream. Samples were taken in three equal-flow sections of the river 's lateral transect at three sites, then analyzed in a fluorometer. The flow in the river was 940 cubic feet per second. The data consist of measured stream mileages and time, distance, and concentration graphs of the dye cloud. The peak concentration traveled through the reach in 24 hours, averaging 1.5 miles per hour; the leading edge took about 22 hours, averaging 1.7 miles per hour; and the trailing edge took 35 hours, averaging 1.0 mile per hour. Data from this study were compared with methods for estimating time of travel for a range of stream discharges.

Down scaled Kjeldahl digestion and flow injection conductometric system for determination of protein content in some traditional northern Thai foods.

PubMed

Yanu, Pattama; Jakmunee, Jaroon

2017-09-01

A flow injection conductometric (FIC) system for determination of total Kjeldahl nitrogen (TKN) was developed for estimating total protein content in food. A small scale Kjeldahl digestion was performed with a short digestion time of only 20min. The digested solution was injected into the FIC system, and TKN was converted to ammonia gas in an alkaline donor stream of the system. The gas diffused through a membrane and dissolved into an acceptor stream causing an increase in conductivity as detected by a detector and recorded as a peak. Under the optimum condition, a linear calibration graph in the range of 4.00-100.00mgL -1 was obtained with LOD of 0.05mgL -1 . A good precision (0.04% RSD, n=11, 30.00mgNL -1 ) and high sample throughput of 72h -1 was achieved. The method was applied for determination of protein in some traditional northern Thai foods, revealing that they are good sources of proteins. Copyright © 2017 Elsevier Ltd. All rights reserved.

Floods of January and February 1980 in California

USGS Publications Warehouse

Wahl, Kenneth L.; Crippen, John R.; Knott, J.M.

1980-01-01

During January and February 1980, storms caused substantial rises in streamflow throughout much of California. In mid-January flooding occurred in the foothills of the Sierra Nevada and in the central coast area. In late January and mid-February, high floodflows in streams in coastal southern California caused much damage and several deaths. The Tijuana River in northern Baja California (Mexico) and southern San Diego County flooded many square miles of lowlands as its flow during two separate flooding episodes exceeded all records. Most reservoirs in San Diego County spilled, several for the first time since their completion. Lake Elsinore, in eastern Riverside County, caused much damage to lakeside property as it filled to an elevation not reached since 1916. The February flooding in southern California was caused by a series of storms separated by short intervals. Some peaks of record were observed, and streamflow throughout the area remained high for a relatively long period. In many streams, the volumes of sustained flow for periods of 7 and 15 consecutive days were the greatest that have occurred during the period of record.

Trends in selected streamflow and stream-channel characteristics for the Chagrin River at Willoughby, Ohio

USGS Publications Warehouse

Koltun, G.F.; Kunze, Allison E.

2002-01-01

Monotonic upward trends in annual mean streamflows and annual 7-day low flows were identified statistically for the streamflow-gaging station on the Chagrin River at Willoughby, Ohio. No monotonic trends were identified for the annual peak streamflow series or partial-duration series of peak streamflows augmented with annual peak streamflows that did not exceed a base discharge of 4,000 cubic feet per second. A plot of cumulative departure of annual precipitation from the long-term mean annual precipitation for the weather-observation station at Hiram, Ohio, indicates a relatively dry period extending from about 1910 to about 1968, followed by a relatively wet period extending from about 1968 to the late 1990s. A plot of cumulative departure of annual mean streamflow from the mean annual streamflow for the Chagrin River at Willoughby, Ohio, closely mimics the shape of the precipitation departure plot, indicating that the annual mean streamflows increased in concert with annual precipitation. These synchronous trends likely explain why upward trends in annual mean streamflows and annual 7-day low flows were observed. A lack of trend in peak streamflows indicates that the intensity and severity of flood-producing storms did not increase appreciably along with the increases in annual precipitation. An analysis of point-of-zero-flow data indicates that the low-water control of the Chagrin River streamflow-gaging station tended to aggrade over the period 1930?93; however, the magnitude of aggradation is sufficiently small that its effect on stages of moderate to large floods would be negligible. Stage values associated with reference streamflows of 500 and 5,000 cubic feet per second tended to remain fairly stable during the period from about 1950 to 1970 and then decreased slightly during the period from about 1970 to 1980, suggesting that the flood-carrying capacity of the stream increased somewhat during the latter period. Since a large flood on May 26, 1989, significant changes have occurred in the relation between stage and streamflow. The most recent relation indicates that stage values associated with streamflows of 500 and 5,000 cubic feet per second are about 0.5 foot and 0.1 foot higher, respectively, than the pre-1989 levels.

Constraints upon the Response of Fish and Crayfish to Environmental Flow Releases in a Regulated Headwater Stream Network

PubMed Central

Chester, Edwin T.; Matthews, Ty G.; Howson, Travis J.; Johnston, Kerrylyn; Mackie, Jonathon K.; Strachan, Scott R.; Robson, Belinda J.

2014-01-01

In dry climate zones, headwater streams are often regulated for water extraction causing intermittency in perennial streams and prolonged drying in intermittent streams. Regulation thereby reduces aquatic habitat downstream of weirs that also form barriers to migration by stream fauna. Environmental flow releases may restore streamflow in rivers, but are rarely applied to headwaters. We sampled fish and crayfish in four regulated headwater streams before and after the release of summer-autumn environmental flows, and in four nearby unregulated streams, to determine whether their abundances increased in response to flow releases. Historical data of fish and crayfish occurrence spanning a 30 year period was compared with contemporary data (electrofishing surveys, Victoria Range, Australia; summer 2008 to summer 2010) to assess the longer–term effects of regulation and drought. Although fish were recorded in regulated streams before 1996, they were not recorded in the present study upstream or downstream of weirs despite recent flow releases. Crayfish (Geocharax sp. nov. 1) remained in the regulated streams throughout the study, but did not become more abundant in response to flow releases. In contrast, native fish (Gadopsis marmoratus, Galaxias oliros, Galaxias maculatus) and crayfish remained present in unregulated streams, despite prolonged drought conditions during 2006–2010, and the assemblages of each of these streams remained essentially unchanged over the 30 year period. Flow release volumes may have been too small or have operated for an insufficient time to allow fish to recolonise regulated streams. Barriers to dispersal may also be preventing recolonisation. Indefinite continuation of annual flow releases, that prevent the unnatural cessation of flow caused by weirs, may eventually facilitate upstream movement of fish and crayfish in regulated channels; but other human–made dispersal barriers downstream need to be identified and ameliorated, to allow native fish to fulfil their life cycles in these headwater streams. PMID:24647407

Geochemical Differences between two adjacent streams in the Tenaya Lake region of Yosemite National Park

NASA Astrophysics Data System (ADS)

Antweiler, R.; Andrews, E. D.

2010-12-01

Tenaya and Murphy Creeks are two small, intermittent streams with drainage basins adjacent to each other in the Tenaya Lake region of Yosemite National Park. Tenaya Creek has a drainage basin area of 3.49 km2 ranging in elevation from 2491 to 3012 m; Murphy Creek has a drainage basin size of 7.07 km2 ranging in elevation from 2485 to 2990 m. Both basins are underlain by the Half Dome and Cathedral Peak Granodiorites (Bateman et al, 1983), with chemical compositions that are practically indistinguishable (Bateman et al, 1988). Both streams derive all of their water from snowmelt and rainfall, normally going dry by early August each year. Tenaya Creek flows primarily south-southwest, whereas Murphy Creek predominantly flows south. For nearly all of Tenaya Creek’s length it is bordered by the Tioga Pass Road, the only highway in Yosemite National Park which crosses the Sierras; on the other hand, all of Murphy Creek (except its mouth) is wilderness. During the summers of 2009 and 2010, both creeks were sampled along most of their lengths for major and trace elements. In addition, both streams have been sampled near their mouths periodically during the spring and summer (until they go dry) since 2007. Water discharge has been continuously monitored during this time. Because these streams derive all of their water from snowmelt and rainfall, the water chemistry of each must originate from atmospheric deposition, weathering of the bedrock and/or human or animal inputs. These factors, along with the similarity of the geology, topography and basin orientation, suggest that the water chemistries of the creeks should be similar. Instead, while measured sulfate concentrations in Tenaya and Murphy Creeks are similar in their upper reaches, Tenaya Creek sulfate values are almost double in the lower reaches. No other major or trace element showed a similar pattern, although sodium, potassium, calcium and rubidium showed modest increases. Other concentration differences between the two streams were mostly in magnitude rather than in downstream trends. For example, concentrations of beryllium, cobalt, lithium, niobium, silica and the rare earth elements (REE) were uniformly higher in Tenaya Creek whereas concentrations of iodide, molybdenum, tellurium, and tungsten were higher in Murphy Creek. During each water year, chloride concentrations increase as discharge decreases in both streams, a pattern seen for most elements. In contrast, aluminum, niobium, thorium and the REE decrease with decreasing flow for both streams, indicating that basin export of these is dominated by snowmelt runoff. Although most chemical constituents show similar patterns between drainages over the course of a water year, sulfate is exceptional: concentrations tend to decrease with decreasing flow in Murphy Creek, whereas sulfate increases at a greater rate than does chloride in Tenaya Creek.

Floods of March-April 1960 in Eastern Nebraska and adjacent states

USGS Publications Warehouse

Brice, H.D.; West, R.E.

1965-01-01

Snowmelt floods, record breaking on many streams and outstanding in terms of total area affected and runoff volumes generated, occurred in late March and early April 1960 on Missouri River tributaries in adjacent parts of six states. In order of area affected, the States are Nebraska, South Dakota, Iowa, Kansas, Minnesota, and Missouri. Five lives were lost, and the estimated damage was $14 million. Main-stem reservoirs kept Missouri River stages substantially below potential unregulated levels. Without regulation by reservoirs, the stage at Sioux City and Omaha would have been about 9 feet higher than it was and the damage would have been many millions of dollars more than actually occurred. The floods were caused by rapid melting of an extensive snow cover of unusual depth and water equivalent, augmented by light to moderate rains. Temperatures almost continuously below normal, beginning in late December and culminating in record lows at many places during the first half of March, resulted in the retention of record snow accumulations, much later and much farther south than normal. The snowfall in eastern Nebraska from December 27 to March 26 was about twice the annual average. The excessive snowfall and below-normal temperatures produced a record-breaking 75-day period of continuous snow cover at Omaha. A rapidly rising, eastward-moving temperature pattern late in March, in combination with an easterly orientation of many Nebraska streams, tended to magnify flood peaks. The rapid temperature rise started about March 18 in western Nebraska but not until March 26 in the eastern part of the State. As a consequence, flood discharges from the headwaters, often bearing heavy ice floes, arrived in the lower reaches simultaneously with or even ahead of the breakup of the unusually heavy ice cover and caused serious jamming. Comparisons of the peak discharges of the 1960 snowmelt floods with those of previous floods reveal several interesting facts. Peak discharges on the Missouri main stem were appreciably less than those in several other years, largely because of effective reservoir control of upstream runoff, but, many tributaries throughout the report area had maximum discharges for their periods of record. Particularly significant are comparisons at some stations for which historical flood data were available. For example, the peak discharge of the Platte River at Louisville, Nebr., was the greatest since at least 1881, and the peak on the Elkhorn River at Waterloo, Nebr., was the greatest snowmelt flood since at least 1912, although it was less than half of the rain peak of June 12, 1944. Following a characteristic pattern for snowmelt floods, the peaks on the smaller streams generally were not unusual, but the cumulative effect of widespread high runoff throughout the stream systems caused higher and more outstanding peaks in the larger basins. Peaks due to local rains of high intensity often are more significant for small areas. Snowmelt floods occur less frequently than rainfall floods in most basins of this flood area.. Studies made for this report show that an average of only about one out of every four maximum annual flood discharges in the report area results primarily from snowmelt. But for streams flowing from north to south in South Dakota and Iowa, the ratio of snowmelt peaks to rainfall peaks is higher. Comparisons of 1960 flood volumes with those for previous floods are even more striking than peak-discharge comparisons. Flood volumes at eight selected stations for the maximum 20-day period during March and April 1960 exceeded all previous 20-day volumes with only one exception; the ratios ranged from 3.11 for Vermillion River near Wakonda, S. Dak., to 0.93 for Elkhorn River at Waterloo, Nebr. The ratio of the 20-day volume to the 1960 annual runoff for the same group of stations ranged from 20 percent at Niobrara River near Spencer, Nebr., to 74 percent on the Vermillion River. For the lat

Complex mixtures of dissolved pesticides show potential aquatic toxicity in a synoptic study of Midwestern U.S. streams

USGS Publications Warehouse

Nowell, Lisa H.; Moran, Patrick W.; Schmidt, Travis S.; Norman, Julia E.; Nakagaki, Naomi; Shoda, Megan E.; Mahler, Barbara J.; Van Metre, Peter C.; Stone, Wesley W.; Sandstrom, Mark W.; Hladik, Michelle L.

2018-01-01

Aquatic organisms in streams are exposed to pesticide mixtures that vary in composition over time in response to changes in flow conditions, pesticide inputs to the stream, and pesticide fate and degradation within the stream. To characterize mixtures of dissolved-phase pesticides and degradates in Midwestern streams, a synoptic study was conducted at 100 streams during May–August 2013. In weekly water samples, 94 pesticides and 89 degradates were detected, with a median of 25 compounds detected per sample and 54 detected per site. In a screening-level assessment using aquatic-life benchmarks and the Pesticide Toxicity Index (PTI), potential effects on fish were unlikely in most streams. For invertebrates, potential chronic toxicity was predicted in 53% of streams, punctuated in 12% of streams by acutely toxic exposures. For aquatic plants, acute but likely reversible effects on biomass were predicted in 75% of streams, with potential longer-term effects on plant communities in 9% of streams. Relatively few pesticides in water—atrazine, acetochlor, metolachlor, imidacloprid, fipronil, organophosphate insecticides, and carbendazim—were predicted to be major contributors to potential toxicity. Agricultural streams had the highest potential for effects on plants, especially in May–June, corresponding to high spring-flush herbicide concentrations. Urban streams had higher detection frequencies and concentrations of insecticides and most fungicides than in agricultural streams, and higher potential for invertebrate toxicity, which peaked during July–August. Toxicity-screening predictions for invertebrates were supported by quantile regressions showing significant associations for the Benthic Invertebrate-PTI and imidacloprid concentrations with invertebrate community metrics for MSQA streams, and by mesocosm toxicity testing with imidacloprid showing effects on invertebrate communities at environmentally relevant concentrations. This study documents the most complex pesticide mixtures yet reported in discrete water samples in the U.S. and, using multiple lines of evidence, predicts that pesticides were potentially toxic to nontarget aquatic life in about half of the sampled streams.

Classification of California streams using combined deductive and inductive approaches: Setting the foundation for analysis of hydrologic alteration

USGS Publications Warehouse

Pyne, Matthew I.; Carlisle, Daren M.; Konrad, Christopher P.; Stein, Eric D.

2017-01-01

Regional classification of streams is an early step in the Ecological Limits of Hydrologic Alteration framework. Many stream classifications are based on an inductive approach using hydrologic data from minimally disturbed basins, but this approach may underrepresent streams from heavily disturbed basins or sparsely gaged arid regions. An alternative is a deductive approach, using watershed climate, land use, and geomorphology to classify streams, but this approach may miss important hydrological characteristics of streams. We classified all stream reaches in California using both approaches. First, we used Bayesian and hierarchical clustering to classify reaches according to watershed characteristics. Streams were clustered into seven classes according to elevation, sedimentary rock, and winter precipitation. Permutation-based analysis of variance and random forest analyses were used to determine which hydrologic variables best separate streams into their respective classes. Stream typology (i.e., the class that a stream reach is assigned to) is shaped mainly by patterns of high and mean flow behavior within the stream's landscape context. Additionally, random forest was used to determine which hydrologic variables best separate minimally disturbed reference streams from non-reference streams in each of the seven classes. In contrast to stream typology, deviation from reference conditions is more difficult to detect and is largely defined by changes in low-flow variables, average daily flow, and duration of flow. Our combined deductive/inductive approach allows us to estimate flow under minimally disturbed conditions based on the deductive analysis and compare to measured flow based on the inductive analysis in order to estimate hydrologic change.

Managed flood effects on beaver pond habitat in a desert riverine ecosystem, bill williams river, Arizona USA

USGS Publications Warehouse

Andersen, D.C.; Shafroth, P.B.; Pritekel, C.M.; O'Neill, M. W.

2011-01-01

The ecological effects of beaver in warm-desert streams are poorly documented, but potentially significant. For example, stream water and sediment budgets may be affected by increased evaporative losses and sediment retention in beaver ponds. We measured physical attributes of beaver pond and adjacent lotic habitats on a regulated Sonoran Desert stream, the Bill Williams River, after ???11 flood-free months in Spring 2007 and Spring 2008. Neither a predicted warming of surface water as it passed through a pond nor a reduction in dissolved oxygen in ponds was consistently observed, but bed sediment sorted to finest in ponds as expected. We observed a river segment-scale downstream rise in daily minimum stream temperature that may have been influenced by the series of ??100 beaver ponds present. Channel cross-sections surveyed before and after an experimental flood (peak flow 65 m3/s) showed net aggradation on nine of 13 cross-sections through ponds and three of seven through lotic reaches. Our results indicate that beaver affect riverine processes in warm deserts much as they do in other biomes. However, effects may be magnified in deserts through the potential for beaver to alter the stream thermal regime and water budget. ?? Society of Wetland Scientists 2011.

Arroyo channel head evolution in a flash-flood-dominated discontinuous ephemeral stream system

USGS Publications Warehouse

DeLong, Stephen B.; Johnson, Joel P.L.; Whipple, Kelin X.

2014-01-01

We study whether arroyo channel head retreat in dryland discontinuous ephemeral streams is driven by surface runoff, seepage erosion, mass wasting, or some combination of these hydrogeomorphic processes. We monitored precipitation, overland flow, soil moisture, and headcut migration over several seasonal cycles at two adjacent rangeland channel heads in southern Arizona. Erosion occurred by headward retreat of vertical to overhanging faces, driven dominantly by surface runoff. No evidence exists for erosion caused by shallow-groundwater–related processes, even though similar theater-headed morphologies are sometimes attributed to seepage erosion by emerging groundwater. At our field site, vertical variation in soil shear strength influenced the persistence of the characteristic theater-head form. The dominant processes of erosion included removal of grains and soil aggregates during even very shallow (1–3 cm) overland flow events by runoff on vertical to overhanging channel headwalls, plunge-pool erosion during higher-discharge runoff events, immediate postrunoff wet mass wasting, and minor intra-event dry mass wasting on soil tension fractures developing subparallel to the headwall. Multiple stepwise linear regression indicates that the migration rate is most strongly correlated with flow duration and total precipitation and is poorly correlated with peak flow depth or time-integrated flow depth. The studied channel heads migrated upslope with a self-similar morphologic form under a wide range of hydrological conditions, and the most powerful flash floods were not always responsible for the largest changes in landscape form in this environment. 

Prevalence and characteristics of voiding difficulties in women: are subjective symptoms substantiated by objective urodynamic data?

PubMed

Groutz, A; Gordon, D; Lessing, J B; Wolman, I; Jaffa, A; David, M P

1999-08-01

To examine the prevalence and characteristics of voiding difficulties in women. Two hundred six consecutive female patients who attended a urogynecology clinic were recruited. Patients were interviewed regarding the presence and severity of symptoms that would suggest voiding difficulties (ie, hesitancy, straining to void, weak or prolonged stream, intermittent stream, double voiding, incomplete emptying, reduction, and positional changes to start or complete voiding). Urodynamic evidence of voiding difficulty was considered as a peak flow rate less than 12 mL/s (voided volume greater than 100 mL), or residual urine volume greater than 150 mL, on two or more readings. Residual urinary volume, flow patterns, and pressure-flow parameters were analyzed and compared between symptomatic and asymptomatic patients who had urodynamic parameters of voiding difficulties. One hundred twenty-seven (61.7%) women reported having voiding difficulty symptoms; 79 others (38.3%) were free of such symptoms. Urodynamic diagnosis of voiding difficulty was made in 40 women (19.4% of the study population): 27 in the symptomatic group and 13 in the asymptomatic group (21.2% and 16.5%, respectively). Only 1 patient had voiding difficulty due to bladder outlet obstruction. All other cases of low flow rate were due to impaired detrusor contractility. Objective evidence of voiding difficulty may be found in both symptomatic and asymptomatic patients and is usually due to impaired detrusor contractility. The clinical significance of the abnormal flow parameters in asymptomatic patients is unclear.

Modeled intermittency risk for small streams in the Upper Colorado River Basin under climate change

USGS Publications Warehouse

Reynolds, Lindsay V.; Shafroth, Patrick B.; Poff, N. LeRoy

2015-01-01

Longer, drier summers projected for arid and semi-arid regions of western North America under climate change are likely to have enormous consequences for water resources and river-dependent ecosystems. Many climate change scenarios for this region involve decreases in mean annual streamflow, late summer precipitation and late-summer streamflow in the coming decades. Intermittent streams are already common in this region, and it is likely that minimum flows will decrease and some perennial streams will shift to intermittent flow under climate-driven changes in timing and magnitude of precipitation and runoff, combined with increases in temperature. To understand current intermittency among streams and analyze the potential for streams to shift from perennial to intermittent under a warmer climate, we analyzed historic flow records from streams in the Upper Colorado River Basin (UCRB). Approximately two-thirds of 115 gaged stream reaches included in our analysis are currently perennial and the rest have some degree of intermittency. Dry years with combinations of high temperatures and low precipitation were associated with more zero-flow days. Mean annual flow was positively related to minimum flows, suggesting that potential future declines in mean annual flows will correspond with declines in minimum flows. The most important landscape variables for predicting low flow metrics were precipitation, percent snow, potential evapotranspiration, soils, and drainage area. Perennial streams in the UCRB that have high minimum-flow variability and low mean flows are likely to be most susceptible to increasing streamflow intermittency in the future.

Estimation of peak-discharge frequency of urban streams in Jefferson County, Kentucky

USGS Publications Warehouse

Martin, Gary R.; Ruhl, Kevin J.; Moore, Brian L.; Rose, Martin F.

1997-01-01

An investigation of flood-hydrograph characteristics for streams in urban Jefferson County, Kentucky, was made to obtain hydrologic information needed for waterresources management. Equations for estimating peak-discharge frequencies for ungaged streams in the county were developed by combining (1) long-term annual peakdischarge data and rainfall-runoff data collected from 1991 to 1995 in 13 urban basins and (2) long-term annual peak-discharge data in four rural basins located in hydrologically similar areas of neighboring counties. The basins ranged in size from 1.36 to 64.0 square miles. The U.S. Geological Survey Rainfall- Runoff Model (RRM) was calibrated for each of the urban basins. The calibrated models were used with long-term, historical rainfall and pan-evaporation data to simulate 79 years of annual peak-discharge data. Peak-discharge frequencies were estimated by fitting the logarithms of the annual peak discharges to a Pearson-Type III frequency distribution. The simulated peak-discharge frequencies were adjusted for improved reliability by application of bias-correction factors derived from peakdischarge frequencies based on local, observed annual peak discharges. The three-parameter and the preferred seven-parameter nationwide urban-peak-discharge regression equations previously developed by USGS investigators provided biased (high) estimates for the urban basins studied. Generalized-least-square regression procedures were used to relate peakdischarge frequency to selected basin characteristics. Regression equations were developed to estimate peak-discharge frequency by adjusting peak-dischargefrequency estimates made by use of the threeparameter nationwide urban regression equations. The regression equations are presented in equivalent forms as functions of contributing drainage area, main-channel slope, and basin development factor, which is an index for measuring the efficiency of the basin drainage system. Estimates of peak discharges for streams in the county can be made for the 2-, 5-, 10-, 25-, 50-, and 100-year recurrence intervals by use of the regression equations. The average standard errors of prediction of the regression equations ranges from ? 34 to ? 45 percent. The regression equations are applicable to ungaged streams in the county having a specific range of basin characteristics.

Stream-Groundwater Interactions Along Streams of the Eastern Sierra Nevada, California: Implications for Assessing Potential Impacts of Flow Diversions

Treesearch

G. Mathias Kondolf

1989-01-01

One of the most fundamental hydrologic determinations to be made in assessing the probable impacts of flow diversions on riparian vegetation is whether flows are gaining or losing water to groundwater in the reach of interest. Flow measurements on eight streams in the Owens River and Mono Lake basins show that stream- groundwater interactions can produce substantial...

Low-flow profiles of the Tallapoosa River and tributaries in Georgia

USGS Publications Warehouse

Carter, R.F.; Hopkins, E.H.; Perlman, H.A.

1988-01-01

Low flow information is provided for use in an evaluation of the capacity of streams to permit withdrawals or to accept waste loads without exceeding the limits of State water quality standards. The report is the fourth in a series of reports presenting the results of a low flow study of all stream basins north of the Fall Line in Georgia. This report covers the part of the Tallapoosa River basin in the Piedmont province of Georgia. The low flow characteristic presented is the minimum average flow for 7 consecutive days with a 10-year recurrence interval (7Q10). The data are presented in tables and shown graphically as ' low flow profiles ' (low flow plotted against distance along a stream channel), and as ' drainage area profiles ' (drainage area plotted against distance along a stream channel). Low flow profiles were constructed by interpolation or extrapolation from points of known low flow data. Low flow profiles are included for all stream reaches where low flow data of sufficient accuracy are available to justify computation of the profiles. Drainage area profiles are included for all stream basins > 5 sq mi, except for those in a few remote areas. Flow records were not adjusted for diversions or other factors that cause measured flows to represent conditions other than natural flow. (Author 's abstract)

Classification of US hydropower dams by their modes of operation

DOE PAGES

McManamay, Ryan A.; Oigbokie, II, Clement O.; Kao, Shih -Chieh; ...

2016-02-19

A key challenge to understanding ecohydrologic responses to dam regulation is the absence of a universally transferable classification framework for how dams operate. In the present paper, we develop a classification system to organize the modes of operation (MOPs) for U.S. hydropower dams and powerplants. To determine the full diversity of MOPs, we mined federal documents, open-access data repositories, and internet sources. W then used CART classification trees to predict MOPs based on physical characteristics, regulation, and project generation. Finally, we evaluated how much variation MOPs explained in sub-daily discharge patterns for stream gages downstream of hydropower dams. After reviewingmore » information for 721 dams and 597 power plants, we developed a 2-tier hierarchical classification based on 1) the storage and control of flows to powerplants, and 2) the presence of a diversion around the natural stream bed. This resulted in nine tier-1 MOPs representing a continuum of operations from strictly peaking, to reregulating, to run-of-river, and two tier-2 MOPs, representing diversion and integral dam-powerhouse configurations. Although MOPs differed in physical characteristics and energy production, classification trees had low accuracies (<62%), which suggested accurate evaluations of MOPs may require individual attention. MOPs and dam storage explained 20% of the variation in downstream subdaily flow characteristics and showed consistent alterations in subdaily flow patterns from reference streams. Lastly, this standardized classification scheme is important for future research including estimating reservoir operations for large-scale hydrologic models and evaluating project economics, environmental impacts, and mitigation.« less

Storm loads of culturable and molecular fecal indicators in an inland urban stream.

PubMed

Liao, Hehuan; Krometis, Leigh-Anne H; Cully Hession, W; Benitez, Romina; Sawyer, Richard; Schaberg, Erin; von Wagoner, Emily; Badgley, Brian D

2015-10-15

Elevated concentrations of fecal indicator bacteria in receiving waters during wet-weather flows are a considerable public health concern that is likely to be exacerbated by future climate change and urbanization. Knowledge of factors driving the fate and transport of fecal indicator bacteria in stormwater is limited, and even less is known about molecular fecal indicators, which may eventually supplant traditional culturable indicators. In this study, concentrations and loading rates of both culturable and molecular fecal indicators were quantified throughout six storm events in an instrumented inland urban stream. While both concentrations and loading rates of each fecal indicator increased rapidly during the rising limb of the storm hydrographs, it is the loading rates rather than instantaneous concentrations that provide a better estimate of transport through the stream during the entire storm. Concentrations of general fecal indicators (both culturable and molecular) correlated most highly with each other during storm events but not with the human-associated HF183 Bacteroides marker. Event loads of general fecal indicators most strongly correlated with total runoff volume, maximum discharge, and maximum turbidity, while event loads of HF183 most strongly correlated with the time to peak flow in a hydrograph. These observations suggest that collection of multiple samples during a storm event is critical for accurate predictions of fecal indicator loading rates and total loads during wet-weather flows, which are required for effective watershed management. In addition, existing predictive models based on general fecal indicators may not be sufficient to predict source-specific genetic markers of fecal contamination. Copyright © 2015 Elsevier B.V. All rights reserved.

Classification of US hydropower dams by their modes of operation

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

McManamay, Ryan A.; Oigbokie, II, Clement O.; Kao, Shih -Chieh

A key challenge to understanding ecohydrologic responses to dam regulation is the absence of a universally transferable classification framework for how dams operate. In the present paper, we develop a classification system to organize the modes of operation (MOPs) for U.S. hydropower dams and powerplants. To determine the full diversity of MOPs, we mined federal documents, open-access data repositories, and internet sources. W then used CART classification trees to predict MOPs based on physical characteristics, regulation, and project generation. Finally, we evaluated how much variation MOPs explained in sub-daily discharge patterns for stream gages downstream of hydropower dams. After reviewingmore » information for 721 dams and 597 power plants, we developed a 2-tier hierarchical classification based on 1) the storage and control of flows to powerplants, and 2) the presence of a diversion around the natural stream bed. This resulted in nine tier-1 MOPs representing a continuum of operations from strictly peaking, to reregulating, to run-of-river, and two tier-2 MOPs, representing diversion and integral dam-powerhouse configurations. Although MOPs differed in physical characteristics and energy production, classification trees had low accuracies (<62%), which suggested accurate evaluations of MOPs may require individual attention. MOPs and dam storage explained 20% of the variation in downstream subdaily flow characteristics and showed consistent alterations in subdaily flow patterns from reference streams. Lastly, this standardized classification scheme is important for future research including estimating reservoir operations for large-scale hydrologic models and evaluating project economics, environmental impacts, and mitigation.« less

Relation of local scour to hydraulic properties at selected bridges in New York

USGS Publications Warehouse

Butch, Gerard K.; ,

1993-01-01

Hydraulic properties, bridge geometry, and basin characteristics at 31 bridges in New York are being investigated to identify factors that affect local scour. Streambed elevations measured by the U.S. Geological Survey and New York State Department of Transportation are used to estimate local-scour depth. Data that show zero or minor scour were included in the analysis to decrease bias and to estimate hydraulic properties related to local scour. The maximum measured local scour at the 31 bridges for a single peak flow was 5.4 feet, but the deepening of scour holes at two sites to 6.1 feet and 7.8 feet by multiple peak flows could indicate that the number or duration of high flows is a factor. Local scour at a pier generally increased as the recurrence interval (magnitude) of the discharge increased, but the correlation between local-scour depth and recurrence interval was inconsistent among study sites. For example, flows with a 2-year recurrence interval produced 2 feet of local scour at two sites, whereas a flow with a recurrence interval produced 2 feet of local scour at two sites, whereas a flow with a recurrence interval of 50 years produced only 0.5 feet of local scour at another site. Local-scour depth increased with water depth, stream velocity, and Reynolds number but did not correlate well with bed-material size, Froude number, pier geometry, friction slope, or several other hydraulic and basin characteristics.

Ice Flow in the North East Greenland Ice Stream

NASA Technical Reports Server (NTRS)

Joughin, Ian; Kwok, Ron; Fahnestock, M.; MacAyeal, Doug

1999-01-01

Early observations with ERS-1 SAR image data revealed a large ice stream in North East Greenland (Fahnestock 1993). The ice stream has a number of the characteristics of the more closely studied ice streams in Antarctica, including its large size and gross geometry. The onset of rapid flow close to the ice divide and the evolution of its flow pattern, however, make this ice stream unique. These features can be seen in the balance velocities for the ice stream (Joughin 1997) and its outlets. The ice stream is identifiable for more than 700 km, making it much longer than any other flow feature in Greenland. Our research goals are to gain a greater understanding of the ice flow in the northeast Greenland ice stream and its outlet glaciers in order to assess their impact on the past, present, and future mass balance of the ice sheet. We will accomplish these goals using a combination of remotely sensed data and ice sheet models. We are using satellite radar interferometry data to produce a complete maps of velocity and topography over the entire ice stream. We are in the process of developing methods to use these data in conjunction with existing ice sheet models similar to those that have been used to improve understanding of the mechanics of flow in Antarctic ice streams.

Evaluation of Topographic wetness index and catchment characteristics on spatially and temporally variable streams across an elevation gradient

NASA Astrophysics Data System (ADS)

Martin, C.

2017-12-01

Topography can be used to delineate streams and quantify the topographic control on hydrological processes of a watershed because geomorphologic processes have shaped the topography and streams of a catchment over time. Topographic Wetness index (TWI) is a common index used for delineating stream networks by predicting location of saturation excess overland flow, but is also used for other physical attributes of a watershed such as soil moisture, groundwater level, and vegetation patterns. This study evaluates how well TWI works across an elevation gradient and the relationships between the active drainage network of four headwater watersheds at various elevations in the Colorado Front Range to topography, geology, climate, soils, elevation, and vegetation in attempt to determine the controls on streamflow location and duration. The results suggest that streams prefer to flow along a path of least resistance which including faults and permeable lithology. Permeable lithologies created more connectivity of stream networks during higher flows but during lower flows dried up. Streams flowing over impermeable lithologies had longer flow duration. Upslope soil hydraulic conductivity played a role on stream location, where soils with low hydraulic conductivity had longer flow duration than soils with higher hydraulic conductivity.Finally TWI thresholds ranged from 5.95 - 10.3 due to changes in stream length and to factors such as geology and soil. TWI had low accuracy for the lowest elevation site due to the greatest change of stream length. In conclusion, structural geology, upslope soil texture, and the permeability of the underlying lithology influenced where the stream was flowing and for how long. Elevation determines climate which influences the hydrologic processes occurring at the watersheds and therefore affects the duration and timing of streams at different elevations. TWI is an adequate tool for delineating streams because results suggest topography has a primary control on the stream locations, but because intermittent streams change throughout the year a algorithm needs to be created to correspond to snow melt and rain events. Also geology indices and soil indices need be considered in addition to topography to have the most accurate derived stream network.

Distribution and biophysical processes of beaded streams in Arctic permafrost landscapes

NASA Astrophysics Data System (ADS)

Arp, C. D.; Whitman, M. S.; Jones, B. M.; Grosse, G.; Gaglioti, B. V.; Heim, K. C.

2015-01-01

Beaded streams are widespread in permafrost regions and are considered a common thermokarst landform. However, little is known about their distribution, how and under what conditions they form, and how their intriguing morphology translates to ecosystem functions and habitat. Here we report on a circum-Arctic survey of beaded streams and a watershed-scale analysis in northern Alaska using remote sensing and field studies. We mapped over 400 channel networks with beaded morphology throughout the continuous permafrost zone of northern Alaska, Canada, and Russia and found the highest abundance associated with medium to high ground-ice content permafrost in moderately sloping terrain. In one Arctic coastal plain watershed, beaded streams accounted for half of the drainage density, occurring primarily as low-order channels initiating from lakes and drained lake basins. Beaded streams predictably transition to alluvial channels with increasing drainage area and decreasing channel slope, although this transition is modified by local controls on water and sediment delivery. The comparisons of one beaded channel using repeat photography between 1948 and 2013 indicate a relatively stable landform, and 14C dating of basal sediments suggest channel formation may be as early as the Pleistocene-Holocene transition. Contemporary processes, such as deep snow accumulation in riparian zones, effectively insulate channel ice and allows for perennial liquid water below most beaded stream pools. Because of this, mean annual temperatures in pool beds are greater than 2 °C, leading to the development of perennial thaw bulbs or taliks underlying these thermokarst features that range from 0.7 to 1.6 m. In the summer, some pools thermally stratify, which reduces permafrost thaw and maintains cold-water habitats. Snowmelt-generated peak flows decrease rapidly by two or more orders of magnitude to summer low flows with slow reach-scale velocity distributions ranging from 0.01 to 0.1 m s-1, yet channel runs still move water rapidly between pools. The repeating spatial pattern associated with beaded stream morphology and hydrological dynamics may provide abundant and optimal foraging habitat for fish. Beaded streams may create important ecosystem functions and habitat in many permafrost landscapes and their distribution and dynamics are only beginning to be recognized in Arctic research.

Distribution and biophysical processes of beaded streams in Arctic permafrost landscapes

USGS Publications Warehouse

Arp, Christopher D.; Whitman, Matthew S.; Jones, Benjamin M.; Grosse, Guido; Gaglioti, Benjamin V.; Heim, Kurt C.

2015-01-01

Beaded streams are widespread in permafrost regions and are considered a common thermokarst landform. However, little is known about their distribution, how and under what conditions they form, and how their intriguing morphology translates to ecosystem functions and habitat. Here we report on a Circum-Arctic survey of beaded streams and a watershed-scale analysis in northern Alaska using remote sensing and field studies. We mapped over 400 channel networks with beaded morphology throughout the continuous permafrost zone of northern Alaska, Canada, and Russia and found the highest abundance associated with medium- to high- ground ice content permafrost in moderately sloping terrain. In the Fish Creek watershed, beaded streams accounted for half of the drainage density, occurring primarily as low-order channels initiating from lakes and drained lake basins. Beaded streams predictably transition to alluvial channels with increasing drainage area and decreasing channel slope, although this transition is modified by local controls on water and sediment delivery. Comparison of one beaded channel using repeat photography between 1948 and 2013 indicate a relatively stable landform and 14C dating of basal sediments suggest channel formation may be as early as the Pleistocene-Holocene transition. Contemporary processes, such as deep snow accumulation in riparian zones effectively insulates channel ice and allows for perennial liquid water below most beaded stream pools. Because of this, mean annual temperatures in pool beds are greater than 2°C, leading to the development of perennial thaw bulbs or taliks underlying these thermokarst features. In the summer, some pools thermally stratify, which reduces permafrost thaw and maintains coldwater habitats. Snowmelt generated peak-flows decrease rapidly by two or more orders of magnitude to summer low flows with slow reach-scale velocity distributions ranging from 0.1 to 0.01 m/s, yet channel runs still move water rapidly between pools. The repeating spatial pattern associated with beaded stream morphology and hydrological dynamics may provide abundant and optimal foraging habitat for fish. Thus, beaded streams may create important ecosystem functions and habitat in many permafrost landscapes and their distribution and dynamics are only beginning to be recognized in Arctic research.

Influence of urbanization pattern on stream flow of a peri-urban catchment under Mediterranean climate

NASA Astrophysics Data System (ADS)

Ferreira, Carla S. S.; Walsh, Rory P. D.; Ferreira, António J. D.; Steenhuis, Tammo S.; Coelho, Celeste A. O.

2015-04-01

The demand for better life quality and lower living costs created a great pressure on peri-urban areas, leading to significant land-use changes. The complexity of mixed land-use patterns, however, presents a challenge to understand the hydrological pathways and streamflow response involved in such changes. This study assesses the impact of a actively changing Portuguese peri-urban area on catchment hydrology. It focuses on quantifying streamflow delivery from contributing areas, of different land-use arrangement and the seasonal influence of the Mediterranean climate on stream discharge. The study focuses on Ribeira dos Covões a small (6 km2) peri-urban catchment on the outskirts of Coimbra, one of the main cities in central Portugal. Between 1958 and 2012 the urban area of the catchment expanded from 8% to 40%, mostly at the expense of agriculture (down from 48% to 4%), with woodland now accounting for the remaining 56% of the catchment area. The urban area comprises contrasting urban settings, associated with older discontinuous arrangement of buildings and urban structures and low population density (<25 inhabitants/km), and recent well-defined urban cores dominated by apartment blocks and high population density (9900 inhabitants/km). The hydrological response of the catchment has been monitored since 2007 by a flume installed at the outlet. In 2009, five rainfall gauges and eight additional water level recorders were installed upstream, to assess the hydrological response of different sub-catchments, characterized by distinct urban patterns and either limestone or sandstone lithologies. Annual runoff coefficients range between 14% and 22%. Changes in annual baseflow index (36-39% of annual rainfall) have been small with urbanization (from 34% to 40%) during the monitoring period itself. Annual runoff coefficients were lowest (14-7%) on catchments >80% woodland and highest (29% on sandstone; 18% on limestone) in the most urbanized (49-53% urban) sub-catchments. Percentage impermeable surface seems to control streamflow particularly during dry periods. Winter runoff was 2-4 times higher than total river flow in the summer dry season in highly urbanized areas, but was 21-fold higher in winter in the least urbanized sub-catchment, denoting greater flow connectivity enhanced by increased soil moisture. Although impermeable surfaces are prone to generate overland flow, the proximity to the stream network is an important parameter determining their hydrological impacts. During the monitoring period, the enlargement of 2% of the urban area at downslope locations in the Covões sub-catchment, led to a 6% increase in the runoff coefficient. In contrast, the urban area increase from 9 to 25% mainly in upslope parts of the Quinta sub-catchment did not increase the peak streamflow due to downslope infiltration and surface retention opportunities. Despite impermeable surfaces enhance overland flow, some urban features (e.g. walls and road embankments) promote surface water retention. The presence of artificial drainage systems, on the other hand, enhances flow connectivity, leading to increasing peak flow and quicker response times (~10 minutes versus 40-50 minutes) as in the Covões sub-catchment. Urbanization impact on streamflow responses may be minimized through planning the land-use mosaic so as to maximize infiltration opportunities. Knowledge of the influence of distinct urban mosaics on flow connectivity and stream discharge is therefore important to landscape managers and should guide urban planning in order to minimize flood hazards.

Low-flow profiles of the Tennessee River tributaries in Georgia

USGS Publications Warehouse

Carter, R.F.; Hopkins, E.H.; Perlman, H.A.

1988-01-01

Low flow information is provided for use in an evaluation of the capacity of streams to permit withdrawals or to accept waste loads without exceeding the limits of State water quality standards. The purpose of this report is to present the results of a compilation of available low flow data in the form of tables and ' 7Q10 flow profiles ' (minimum average flow for 7 consecutive days with a 10-yr recurrence interval) (7Q10 flow plotted against distance along a stream channel) for all stream reaches of the Tennessee River tributaries where sufficient data of acceptable accuracy are available. Drainage area profiles are included for all stream basins larger than 5 sq mi, except for those in a few remote areas. This report is the fifth in a series of reports that will cover all stream basins north of the Fall Line in Georgia. It includes the parts of the Tennessee River basin in Georgia. Flow records were not adjusted for diversions or other factors that cause measured flows to represent other than natural flow conditions. The 7-day minimum flow profile was omitted for stream reaches where natural flow was known to be altered significantly. (Lantz-PTT)

Holocene alluvial stratigraphy and response to climate change in the Roaring River valley, Front Range, Colorado, USA

USGS Publications Warehouse

Madole, Richard F.

2012-01-01

Stratigraphic analyses and radiocarbon geochronology of alluvial deposits exposed along the Roaring River, Colorado, lead to three principal conclusions: (1) the opinion that stream channels in the higher parts of the Front Range are relics of the Pleistocene and nonalluvial under the present climate, as argued in a water-rights trial USA v. Colorado, is untenable, (2) beds of clast-supported gravel alternate in vertical succession with beds of fine-grained sediment (sand, mud, and peat) in response to centennial-scale changes in snowmelt-driven peak discharges, and (3) alluvial strata provide information about Holocene climate history that complements the history provided by cirque moraines, periglacial deposits, and paleontological data. Most alluvial strata are of late Holocene age and record, among other things, that: (1) the largest peak flows since the end of the Pleistocene occurred during the late Holocene; (2) the occurrence of a mid- to late Holocene interval (~2450–1630(?) cal yr BP) of warmer climate, which is not clearly identified in palynological records; and (3) the Little Ice Age climate seems to have had little impact on stream channels, except perhaps for minor (~1 m) incision. Published

Effect of land use and hydrological processes on Escherichia coli concentrations in streams of tropical, humid headwater catchments.

PubMed

Rochelle-Newall, Emma J; Ribolzi, Olivier; Viguier, Marion; Thammahacksa, Chanthamousone; Silvera, Norbert; Latsachack, Keooudone; Dinh, Rinh Pham; Naporn, Piyapong; Sy, Hai Tran; Soulileuth, Bounsamay; Hmaimum, Nikom; Sisouvanh, Pem; Robain, Henri; Janeau, Jean-Louis; Valentin, Christian; Boithias, Laurie; Pierret, Alain

2016-09-08

Lack of access to clean water and adequate sanitation continues to be a major brake on development. Here we present the results of a 12-month investigation into the dynamics of Escherichia coli, a commonly used indicator of faecal contamination in water supplies, in three small, rural catchments in Laos, Thailand and Vietnam. We show that land use and hydrology are major controlling factors of E. coli concentrations in streamwater and that the relative importance of these two factors varies between the dry and wet seasons. In all three catchments, the highest concentrations were observed during the wet season when storm events and overland flow were highest. However, smaller peaks of E. coli concentration were also observed during the dry season. These latter correspond to periods of intense farming activities and small, episodic rain events. Furthermore, vegetation type, through land use and soil surface crusting, combined with mammalian presence play an important role in determining E. coli loads in the streams. Finally, sampling during stormflow revealed the importance of having appropriate sampling protocols if information on maximum contamination levels is required as grab sampling at a fixed time step may miss important peaks in E. coli numbers.

Effect of land use and hydrological processes on Escherichia coli concentrations in streams of tropical, humid headwater catchments

NASA Astrophysics Data System (ADS)

Rochelle-Newall, Emma J.; Ribolzi, Olivier; Viguier, Marion; Thammahacksa, Chanthamousone; Silvera, Norbert; Latsachack, Keooudone; Dinh, Rinh Pham; Naporn, Piyapong; Sy, Hai Tran; Soulileuth, Bounsamay; Hmaimum, Nikom; Sisouvanh, Pem; Robain, Henri; Janeau, Jean-Louis; Valentin, Christian; Boithias, Laurie; Pierret, Alain

2016-09-01

Lack of access to clean water and adequate sanitation continues to be a major brake on development. Here we present the results of a 12-month investigation into the dynamics of Escherichia coli, a commonly used indicator of faecal contamination in water supplies, in three small, rural catchments in Laos, Thailand and Vietnam. We show that land use and hydrology are major controlling factors of E. coli concentrations in streamwater and that the relative importance of these two factors varies between the dry and wet seasons. In all three catchments, the highest concentrations were observed during the wet season when storm events and overland flow were highest. However, smaller peaks of E. coli concentration were also observed during the dry season. These latter correspond to periods of intense farming activities and small, episodic rain events. Furthermore, vegetation type, through land use and soil surface crusting, combined with mammalian presence play an important role in determining E. coli loads in the streams. Finally, sampling during stormflow revealed the importance of having appropriate sampling protocols if information on maximum contamination levels is required as grab sampling at a fixed time step may miss important peaks in E. coli numbers.

Holocene alluvial stratigraphy and response to climate change in the Roaring River valley, Front Range, Colorado, USA

NASA Astrophysics Data System (ADS)

Madole, Richard F.

2012-09-01

Stratigraphic analyses and radiocarbon geochronology of alluvial deposits exposed along the Roaring River, Colorado, lead to three principal conclusions: (1) the opinion that stream channels in the higher parts of the Front Range are relics of the Pleistocene and nonalluvial under the present climate, as argued in a water-rights trial USA v. Colorado, is untenable, (2) beds of clast-supported gravel alternate in vertical succession with beds of fine-grained sediment (sand, mud, and peat) in response to centennial-scale changes in snowmelt-driven peak discharges, and (3) alluvial strata provide information about Holocene climate history that complements the history provided by cirque moraines, periglacial deposits, and paleontological data. Most alluvial strata are of late Holocene age and record, among other things, that: (1) the largest peak flows since the end of the Pleistocene occurred during the late Holocene; (2) the occurrence of a mid- to late Holocene interval (~ 2450-1630(?) cal yr BP) of warmer climate, which is not clearly identified in palynological records; and (3) the Little Ice Age climate seems to have had little impact on stream channels, except perhaps for minor (~ 1 m) incision.

Stream Intermittency Sensors Monitor the Onset and Duration of Stream Flow Along a Channel Network During Storms

NASA Astrophysics Data System (ADS)

Jensen, C.; McGuire, K. J.

2017-12-01

Headwater streams are spatially extensive, accounting for a majority of global stream length, and supply downstream water bodies with water, sediment, organic matter, and pollutants. Much of this transmission occurs episodically during storms when stream flow and connectivity are high. Many headwaters are temporary streams that expand and contract in length in response to storms and seasonality. Understanding where and when streams carry flow is critical for conserving headwaters and protecting downstream water quality, but storm events are difficult to study in small catchments. The rise and fall of stream flow occurs rapidly in headwaters, making observation of the entire stream network difficult. Stream intermittency sensors that detect the presence or absence of water can reveal wetting and drying patterns over short time scales. We installed 50 intermittency sensors along the channel network of a small catchment (35 ha) in the Valley and Ridge of southwest Virginia. Previous work shows stream length is highly variable in this shale catchment, as the drainage density spans two orders of magnitude. The sensors record data every 15 minutes for one year to capture different seasons, antecedent moisture conditions, and precipitation rates. We seek to determine whether hysteresis between stream flow and network length occurs on the rising and falling limbs of events and if reach-scale characteristics such as valley width explain spatial patterns of flow duration. Our results indicate reaches with a wide, sediment-filled valley floor carry water for shorter periods of time than confined channel segments with steep valley side slopes. During earlier field mapping surveys, we only observed flow in a few of the tributaries for the wettest conditions mapped. The sensors now show that these tributaries flow more frequently during much smaller storms, but only for brief periods of time (< 1 hour). The high temporal sampling resolution of the sensors permits a more realistic estimate of flow duration in temporary streams, which field surveys may, otherwise, underestimate. Such continuous datasets on stream network length will allow researchers to more accurately assess the value of headwater reaches for contributions to environmental services such as aquatic habitat, hyporheic exchange, and mass fluxes of solutes.

Streamflow Characteristics of Streams in the Helmand Basin, Afghanistan

USGS Publications Warehouse

Williams-Sether, Tara

2008-01-01

Statistical summaries of streamflow data for all historical streamflow-gaging stations for the Helmand Basin upstream from the Sistan Wetlands are presented in this report. The summaries for each streamflow-gaging station include (1) manuscript (station description), (2) graph of the annual mean discharge for the period of record, (3) statistics of monthly and annual mean discharges, (4) graph of the annual flow duration, (5) monthly and annual flow duration, (6) probability of occurrence of annual high discharges, (7) probability of occurrence of annual low discharges, (8) probability of occurrence of seasonal low discharges, (9) annual peak discharge and corresponding gage height for the period of record, and (10) monthly and annual mean discharges for the period of record.

Event-Based Analysis of Rainfall-Runoff Response to Assess Wetland-Stream Interaction in the Prairie Pothole Region

NASA Astrophysics Data System (ADS)

Haque, M. A.; Ross, C.; Schmall, A.; Bansah, S.; Ali, G.

2016-12-01

Process-based understanding of wetland response to precipitation is needed to quantify the extent to which non-floodplain wetlands - such as Prairie potholes - generate flow and transmit that flow to nearby streams. While measuring wetland-stream (W-S) interaction is difficult, it is possible to infer it by examining hysteresis characteristics between wetland and stream stage during individual precipitation events. Hence, to evaluate W-S interaction, 10 intact and 10 altered/lost potholes were selected for study; they are located in Broughton's Creek Watershed (Manitoba, Canada) on both sides of a 5 km creek reach. Stilling wells (i.e., above ground wells) were deployed in the intact and altered wetlands to monitor surface water level fluctuations while water table wells were drilled below drainage ditches to a depth of 1 m to monitor shallow groundwater fluctuations. All stilling wells and water table wells were equipped with capacitance water level loggers to monitor fluctuations in surface water and shallow groundwater every 15 minutes. In 2013 (normal year) and 2014 (wet year), 15+ precipitation events were identified and scatter plots of wetland (x-axis) versus stream (y-axis) stage were built to identify W-S hysteretic dynamics. Initial data analysis reveals that in dry antecedent conditions, intact and altered wetlands show clockwise W-S relations, while drained wetlands show anticlockwise W-S hysteresis. However, in wetter antecedent conditions, all wetland types show anticlockwise hysteresis. Future analysis will target the identification of thresholds in antecedent moisture conditions that determine significant changes in event wetland response characteristics (e.g., the delay between the start of rainfall and stream stage, the maximum water level rise in each wetland during each event, the delay between the start of rainfall and peak wetland stage) as well as hysteresis properties (e.g., gradient and area of the hysteresis loop).

Bank-derived material dominates fluvial sediment in a suburban Chesapeake Bay watershed

NASA Astrophysics Data System (ADS)

Cashman, M. J.; Gellis, A.; Gorman-Sanisaca, L.; Noe, G. B.; Cogliandro, V.; Baker, A.

2017-12-01

Excess fine sediment is a leading cause of ecological degradation within the Chesapeake Bay watershed. The Piedmont physiographic province, which includes parts of the Washington, D.C. metro area, has the highest sediment yields in the Chesapeake Bay. In order to effectively employ sediment mitigation measures, it is necessary to identify and quantify the contributions of sediments sources within rapidly urbanizing areas in the Piedmont. This sediment fingerprinting study examines the inputs of various sediment sources to Upper Difficult Run (14.2 km2; 22.6% impervious surface), an urbanized watershed in Fairfax County, Virginia. A source sediment library was constructed from collections of stream bank material, forest soils, and road dust from across the watershed. Target fluvial sediments were collected from fine channel margin deposits and from suspended sediment using an autosampler during 16 storm events from 2008 - 2012. Apportionment of the target samples to the source sediments was performed using Sed_SAT, a publically available toolkit for sediment fingerprinting. Bed sediment was found to be dominated by stream bank sources (mean: 96%), with minor contributions from forest (4%) and no detectable contribution from roads (0%). Suspended fine sediments were also found to predominantly originate from stream bank sources (SSC-weighted mean: 91%), with minor contributions from roads (8%), and negligible contributions from forests (1%). Stream bank sources dominated at all discharges, with the greatest contributions from overland sources found only at low discharges. On the rising limb of the hydrograph and at peak flow, sediment concentrations increased due to increasing contributions of bank material rather than surface erosion caused by overland flow. Results demonstrate that stream bank erosion is responsible for the vast majority of fine sediment occurring in this suburban basin of the Chesapeake Bay watershed. This is likely a consequence of storm-water energy characteristics in urbanized watersheds resulting in channel widening and bank failure. Thus, bank stabilization, channel restoration, and/or storm water management to attenuate stream energy may improve the ecological condition of these waterbodies.

Geomorphic controls on hyporheic exchange flow in mountain streams.

Treesearch

T. Kasahara; S.M. Wondzell

2003-01-01

Hyporheic exchange flows were simulated using MODFLOW and MODPATH to estimate relative effects of channel morphologic features on the extent of the hyporheic zone, on hyporheic exchange flow, and on the residence time of stream water in the hyporheic zone. Four stream reaches were compared in order to examine the influence of stream size and channel constraint. Within...

Experimental study of streaming flows associated with ultrasonic levitators

NASA Astrophysics Data System (ADS)

Trinh, E. H.; Robey, J. L.

1994-11-01

Steady-state acoustic streaming flow patterns have been observed during the operation of a variety of resonant single-axis ultrasonic levitators in a gaseous environment and in the 20-37 kHz frequency range. Light sheet illumination and scattering from smoke particles have revealed primary streaming flows which display different characteristics at low and high sound pressure levels. Secondary macroscopic streaming cells around levitated samples are superimposed on the primary streaming flow pattern generated by the standing wave. These recorded flows are quite reproducible, and are qualitatively the same for a variety of levitator physical geometries. An onset of flow instability can also be recorded in nonisothermal systems, such as levitated spot-heated samples when the resonance conditions are not exactly satisfied. A preliminary qualitative interpretation of these experimental results is presented in terms of the superposition of three discrete sets of circulation cells operating on different spatial scales. These relevant length scales are the acoustic wavelength, the levitated sample size, and finally the acoustic boundary layer thickness. This approach fails, however, to explain the streaming flow-field morphology around liquid drops levitated on Earth. Observation of the interaction between the flows cells and the levitated samples also suggests the existence of a steady-state torque induced by the streaming flows.

Subsurface Controls on Stream Intermittency in a Semi-Arid Landscape

NASA Astrophysics Data System (ADS)

Dohman, J.; Godsey, S.; Thackray, G. D.; Hale, R. L.; Wright, K.; Martinez, D.

2017-12-01

Intermittent streams currently constitute 30% to greater than 50% of the global river network. In addition, the number of intermittent streams is expected to increase due to changes in land use and climate. These streams provide important ecosystem services, such as water for irrigation, increased biodiversity, and high rates of nutrient cycling. Many hydrological studies have focused on mapping current intermittent flow regimes or evaluating long-term flow records, but very few have investigated the underlying causes of stream intermittency. The disconnection and reconnection of surface flow reflects the capacity of the subsurface to accommodate flow, so characterizing subsurface flow is key to understanding stream drying. We assess how subsurface flow paths control local surface flows during low-flow periods, including intermittency. Water table dynamics were monitored in an intermittent reach of Gibson Jack Creek in southeastern Idaho. Four transects were delineated with a groundwater well located in the hillslope, riparian zone, and in the stream, for a total of 12 groundwater wells. The presence or absence of surface flow was determined by frequent visual observations as well as in situ loggers every 30m along the 200m study reach. The rate of surface water drying was measured in conjunction with temperature, precipitation, subsurface hydraulic conductivity, hillslope-riparian-stream connectivity and subsurface travel time. Initial results during an unusually wet year suggest different responses in reaches that were previously observed to occasionally cease flowing. Flows in the intermittent reaches had less coherent and lower amplitude diel variations during base flow periods than reaches that had never been observed to dry out. Our findings will help contribute to our understanding of mechanisms driving expansion and contraction cycles in intermittent streams, increase our ability to predict how land use and climate change will affect flow regimes, and improve management of our critical water resources.

StreamStats: A water resources web application

USGS Publications Warehouse

Ries, Kernell G.; Guthrie, John G.; Rea, Alan H.; Steeves, Peter A.; Stewart, David W.

2008-01-01

Streamflow statistics, such as the 1-percent flood, the mean flow, and the 7-day 10-year low flow, are used by engineers, land managers, biologists, and many others to help guide decisions in their everyday work. For example, estimates of the 1-percent flood (the flow that is exceeded, on average, once in 100 years and has a 1-percent chance of being exceeded in any year, sometimes referred to as the 100-year flood) are used to create flood-plain maps that form the basis for setting insurance rates and land-use zoning. This and other streamflow statistics also are used for dam, bridge, and culvert design; water-supply planning and management; water-use appropriations and permitting; wastewater and industrial discharge permitting; hydropower facility design and regulation; and the setting of minimum required streamflows to protect freshwater ecosystems. In addition, researchers, planners, regulators, and others often need to know the physical and climatic characteristics of the drainage basins (basin characteristics) and the influence of human activities, such as dams and water withdrawals, on streamflow upstream from locations of interest to understand the mechanisms that control water availability and quality at those locations. Knowledge of the streamflow network and downstream human activities also is necessary to adequately determine whether an upstream activity, such as a water withdrawal, can be allowed without adversely affecting downstream activities.Streamflow statistics could be needed at any location along a stream. Most often, streamflow statistics are needed at ungaged sites, where no streamflow data are available to compute the statistics. At U.S. Geological Survey (USGS) streamflow data-collection stations, which include streamgaging stations, partial-record stations, and miscellaneous-measurement stations, streamflow statistics can be computed from available data for the stations. Streamflow data are collected continuously at streamgaging stations. Streamflow measurements are collected systematically over a period of years at partial-record stations to estimate peak-flow or low-flow statistics. Streamflow measurements usually are collected at miscellaneous-measurement stations for specific hydrologic studies with various objectives.StreamStats is a Web-based Geographic Information System (GIS) application that was created by the USGS, in cooperation with Environmental Systems Research Institute, Inc. (ESRI)1, to provide users with access to an assortment of analytical tools that are useful for water-resources planning and management. StreamStats functionality is based on ESRI’s ArcHydro Data Model and Tools, described on the Web at http://resources.arcgis.com/en/communities/hydro/01vn0000000s000000.htm. StreamStats allows users to easily obtain streamflow statistics, basin characteristics, and descriptive information for USGS data-collection stations and user-selected ungaged sites. It also allows users to identify stream reaches that are upstream and downstream from user-selected sites, and to identify and obtain information for locations along the streams where activities that may affect streamflow conditions are occurring. This functionality can be accessed through a map-based user interface that appears in the user’s Web browser, or individual functions can be requested remotely as Web services by other Web or desktop computer applications. StreamStats can perform these analyses much faster than historically used manual techniques.StreamStats was designed so that each state would be implemented as a separate application, with a reliance on local partnerships to fund the individual applications, and a goal of eventual full national implementation. Idaho became the first state to implement StreamStats in 2003. By mid-2008, 14 states had applications available to the public, and 18 other states were in various stages of implementation.

Local flow measurements at the inlet spike tip of a Mach 3 supersonic cruise airplane

NASA Technical Reports Server (NTRS)

Johnson, H. J.; Montoya, E. J.

1973-01-01

The flow field at the left inlet spike tip of a YF-12A airplane was examined using at 26 deg included angle conical flow sensor to obtain measurements at free-stream Mach numbers from 1.6 to 3.0. Local flow angularity, Mach number, impact pressure, and mass flow were determined and compared with free-stream values. Local flow changes occurred at the same time as free-stream changes. The local flow usually approached the spike centerline from the upper outboard side because of spike cant and toe-in. Free-stream Mach number influenced the local flow angularity; as Mach number increased above 2.2, local angle of attack increased and local sideslip angle decreased. Local Mach number was generally 3 percent less than free-stream Mach number. Impact-pressure ratio and mass flow ratio increased as free-stream Mach number increased above 2.2, indicating a beneficial forebody compression effect. No degradation of the spike tip instrumentation was observed after more than 40 flights in the high-speed thermal environment encountered by the airplane. The sensor is rugged, simple, and sensitive to small flow changes. It can provide accurate imputs necessary to control an inlet.

Circuitous to single thread: post-dam geomorphic transformation of the Colorado River in its delta

NASA Astrophysics Data System (ADS)

Mueller, E. R.; Schmidt, J. C.

2017-12-01

The Colorado River in its delta has transformed from a maze of secondary and distributary channels to an intermittent or ephemeral stream largely disconnected from formerly active channels and floodplains. Periodic post-dam floods have demonstrated that channel migration and shifting during floods increased the extent and diversity of riparian vegetation, and suggested that restoration of fluvial processes that promote re-activation of these former channels may enhance ecosystem rehabilitation. But restoration efforts in the delta are complicated by the fact that the Colorado River has the largest reservoir size in relation to its mean annual flow of any large river in North America and most of its sediment supply is completely blocked in upstream reservoirs. As a result, small controlled floods intended to inundate formerly active channels and rejuvenate riparian vegetation must consider the new relationship between stream flow and the delta's transformed geomorphology. Post-dam channel change has been dominated by the abandonment of secondary and distributary channels, with 3 to 4 meters of bed incision in the upstream part of the delta that diminishes downstream. Initial bed incision of 2 to 3 meters occurred rapidly following completion of Hoover Dam in 1936, before further upstream water development reduced delta flows to near zero by the mid-1960s. The largest post-dam floods occurred in the 1980s, which resulted in 10s to 100s of meters of lateral migration, channel switching, and the reactivation of secondary channels and floodplains rarely inundated since dam completion. Smaller flow pulses in the 1990s and 2000s further incised the thalweg to its minimum elevation, resulting in a narrow single-thread channel inset within the multi-channel surface active during the 1980s. In 2014, an experimental pulse flow was released to the river channel with a peak discharge approximately 5% of the typical pre-dam flood peak. Topographic change was confined to the main channel where post-dam bed incision resulted in larger depths and flow velocities, although some secondary channels were inundated. Post-dam channel incision, combined with the rapid downstream loss of flow through infiltration, has reduced the area where secondary channels might be formed or re-activated during small controlled floods in the delta.

Estimated Perennial Streams of Idaho and Related Geospatial Datasets

USGS Publications Warehouse

Rea, Alan; Skinner, Kenneth D.

2009-01-01

The perennial or intermittent status of a stream has bearing on many regulatory requirements. Because of changing technologies over time, cartographic representation of perennial/intermittent status of streams on U.S. Geological Survey (USGS) topographic maps is not always accurate and (or) consistent from one map sheet to another. Idaho Administrative Code defines an intermittent stream as one having a 7-day, 2-year low flow (7Q2) less than 0.1 cubic feet per second. To establish consistency with the Idaho Administrative Code, the USGS developed regional regression equations for Idaho streams for several low-flow statistics, including 7Q2. Using these regression equations, the 7Q2 streamflow may be estimated for naturally flowing streams anywhere in Idaho to help determine perennial/intermittent status of streams. Using these equations in conjunction with a Geographic Information System (GIS) technique known as weighted flow accumulation allows for an automated and continuous estimation of 7Q2 streamflow at all points along a stream, which in turn can be used to determine if a stream is intermittent or perennial according to the Idaho Administrative Code operational definition. The selected regression equations were applied to create continuous grids of 7Q2 estimates for the eight low-flow regression regions of Idaho. By applying the 0.1 ft3/s criterion, the perennial streams have been estimated in each low-flow region. Uncertainty in the estimates is shown by identifying a 'transitional' zone, corresponding to flow estimates of 0.1 ft3/s plus and minus one standard error. Considerable additional uncertainty exists in the model of perennial streams presented in this report. The regression models provide overall estimates based on general trends within each regression region. These models do not include local factors such as a large spring or a losing reach that may greatly affect flows at any given point. Site-specific flow data, assuming a sufficient period of record, generally would be considered to represent flow conditions better at a given site than flow estimates based on regionalized regression models. The geospatial datasets of modeled perennial streams are considered a first-cut estimate, and should not be construed to override site-specific flow data.

Experimental reductions in stream flow alter litter processing and consumer subsidies in headwater streams

Treesearch

Robert M. Northington; Jackson R. Webster

2017-01-01

SummaryForested headwater streams are connected to their surrounding catchments by a reliance on terrestrial subsidies. Changes in precipitation patterns and stream flow represent a potential disruption in stream ecosystem function, as the delivery of terrestrial detritus to aquatic consumers and...

Streaming reversal of energetic particles in the magnetotail during a substorm

NASA Technical Reports Server (NTRS)

Lui, A. T. Y.; Williams, D. J.; Eastman, T. E.; Frank, L. A.; Akasofu, S.-I.

1984-01-01

A case of reversal in the streaming anisotropy of energetic ions and in the plasma flow observed from the IMP 8 spacecraft during a substorm on February 8, 1978 is studied in detail using measurements of energetic particles, plasma, and magnetic field. Four new features emerge when high time resolution data are examined in detail. The times of streaming reversal of energetic particles in different energy ranges do not coincide with the time of plasma flow reversal. Qualitatively different velocity distributions are observed in earthward and tailward plasma flows during the observed flow reversal intervals. Strong tailward streaming of energetic particles can be detected during northward magnetic field environments and, conversely, earthward streaming in southward field environments. During the period of tailward streaming of energetic particles, earthward streaming fluxes are occasionally detected.

78 FR 65306 - Best Practices for Continuous Monitoring of Temperature and Flow in Wadeable Streams

Federal Register 2010, 2011, 2012, 2013, 2014

2013-10-31

... Practices for Continuous Monitoring of Temperature and Flow in Wadeable Streams AGENCY: Environmental... Monitoring of Temperature and Flow in Wadeable Streams'' (EPA/600/R-13/170). The EPA also is announcing that... Development. The report describes best practices for the deployment of continuous temperature and flow sensors...

On the Nature of the High-Speed Plasma Flows in the 2005 September 13 Flare

NASA Astrophysics Data System (ADS)

Liu, C.; Choudhary, D. P.; Deng, N.; Wang, H.

2008-05-01

A long-duration, successive flaring event accompanied by fast CMEs occurred on 2005 September 13 in the NOAA AR 10808 and was classified as 2B/X1.5 with peak time at 19:27 UT. In this study, we report direct and unambiguous observations of high-speed hot plasma flows associated with the second major peak in soft X-ray that reached X1.4 on the GOES scale at 20:05 UT. The flows are seen as streams of enhanced density in extreme-UV traveling above and toward arcades of the secondary compact-loop flare at the main δ spot with an apparent speed as high as ~350~km~s-1, and the times when they are initiated correspond to those of bursts of nonthermal emissions in hard X-rays (HXRs) and microwaves. In Hα, the flows appear to become emission later on when approaching the lower atmosphere nearby the flaring magnetic polarity inversion line and subsequently trigger a subflare with propagating kernels. It is particularly notable that the flows are spatially and temporally related to HXR sources detected by RHESSI and a large erupting flux rope. We scrutinize several scenarios to investigate the nature of the observed high-speed flows. We conclude that the observations could be interpreted in terms of materials braking away from a preceding filament eruption and falling gravitationally back into the flaring region. A separate scenario is that the observed flow motion could be a manifestation of sunward reconnection outflow supporting the standard reconnection model.

Impact of chevron spacing and asymmetric distribution on supersonic jet acoustics and flow

NASA Astrophysics Data System (ADS)

Heeb, N.; Gutmark, E.; Kailasanath, K.

2016-05-01

An experimental investigation into the effect of chevron spacing and distribution on supersonic jets was performed. Cross-stream and streamwise particle imaging velocimetry measurements were used to relate flow field modification to sound field changes measured by far-field microphones in the overexpanded, ideally expanded, and underexpanded regimes. Drastic modification of the jet cross-section was achieved by the investigated configurations, with both elliptic and triangular shapes attained downstream. Consequently, screech was nearly eliminated with reductions in the range of 10-25 dB depending on the operating condition. Analysis of the streamwise velocity indicated that both the mean shock spacing and strength were reduced resulting in an increase in the broadband shock associated noise spectral peak frequency and a reduction in the amplitude, respectively. Maximum broadband shock associated noise amplitude reductions were in the 5-7 dB range. Chevron proximity was found to be the primary driver of peak vorticity production, though persistence followed the opposite trend. The integrated streamwise vorticity modulus was found to be correlated with peak large scale turbulent mixing noise reduction, though optimal overall sound pressure level reductions did not necessarily follow due to the shock/fine scale mixing noise sources. Optimal large scale mixing noise reductions were in the 5-6 dB range.

Mean annual runoff and peak flow estimates based on channel geometry of streams in northeastern and western Montana

USGS Publications Warehouse

Parrett, Charles; Omang, R.J.; Hull, J.A.

1983-01-01

Equations for estimating mean annual runoff and peak discharge from measurements of channel geometry were developed for western and northeastern Montana. The study area was divided into two regions for the mean annual runoff analysis, and separate multiple-regression equations were developed for each region. The active-channel width was determined to be the most important independent variable in each region. The standard error of estimate for the estimating equation using active-channel width was 61 percent in the Northeast Region and 38 percent in the West region. The study area was divided into six regions for the peak discharge analysis, and multiple regression equations relating channel geometry and basin characteristics to peak discharges having recurrence intervals of 2, 5, 10, 25, 50 and 100 years were developed for each region. The standard errors of estimate for the regression equations using only channel width as an independent variable ranged from 35 to 105 percent. The standard errors improved in four regions as basin characteristics were added to the estimating equations. (USGS)

Flood of March 1997 in southern Ohio

USGS Publications Warehouse

Jackson, K.S.; Vivian, S.A.; Diam, F.J.; Crecelius, C.J.

1997-01-01

Rainfall amounts of up to 12 inches produced by thunderstorms during March 1-2, 1997 resulted in severe flooding throughout much of southern Ohio. Eighteen counties were declared Federal and State disaster areas. Cost estimates of damage in Ohio from the flooding are nearly $180 million. About 6,500 residences and more than 800 businesses were affected by flooding. Nearly 20,000 persons were evacuated, and 5 deaths were attributed to the flooding. Record peak stage and streamflow were recorded at U.S. Geological Survey (USGS) streamflow-gaging stations on Ohio Brush Creek near West Union and Shade River near Chester. The peak streamflow at these two locations exceeded the estimate of the 100-year-recurrence- interval peak streamflow. The recurrence intervals of peak stream flow at selected USGS streamflow gaging stations throughout southern Ohio ranged from less than 2 years to greater than 100 years. The most severe flooding in the State was generally confined to areas within 50 to 70 miles of the Ohio River. Many communities along the Ohio River experienced the worst flooding in more than 30 years.

Assessing the Vulnerability of Streams to Increased Frequency and Severity of Low Flows in the Southeastern United States

NASA Astrophysics Data System (ADS)

Konrad, C. P.

2014-12-01

A changing climate poses risks to the availability and quality of water resources. Among the risks, increased frequency and severity of low flow periods in streams would be significant for many in-stream and out-of-stream uses of water. While down-scaled climate projections serve as the basis for understanding impacts of climate change on hydrologic systems, a robust framework for risk assessment incorporates multiple dimensions of risks including the vulnerability of hydrologic systems to climate change impacts. Streamflow records from the southeastern US were examined to assess the vulnerability of streams to increased frequency and severity of low flows. Long-term (>50 years) records provide evidence of more frequent and severe low flows in more streams than would be expected from random chance. Trends in low flows appear to be a result of changes in the temporal distribution rather than the annual amount of preciptation and/or in evaporation. Base flow recession provides an indicator of a stream's vulnerability to such changes. Linkages between streamflow patterns across temporal scales can be used for understanding and asessing stream responses to the various possible expressions of a changing climate.

Availability and distribution of low flow in Anahola Stream, Kauaʻi, Hawaiʻi

USGS Publications Warehouse

Cheng, Chui Ling; Wolff, Reuben H.

2012-01-01

Anahola Stream is a perennial stream in northeast Kauaʻi, Hawaiʻi, that supports agricultural, domestic, and cultural uses within its drainage basin. Beginning in the late 19th century, Anahola streamflow was diverted by Makee Sugar Company at altitudes of 840 feet (upper intake) and 280 feet (lower intake) for irrigating sugarcane in the Keālia area. When sugarcane cultivation in the Keālia area ceased in 1988, part of the Makee Sugar Company’s surface-water collection system (Makee diversion system) in the Anahola drainage basin was abandoned. In an effort to better manage available surface-water resources, the State of Hawaiʻi Department of Hawaiian Home Lands is considering using the existing ditches in the Anahola Stream drainage basin to provide irrigation water for Native Hawaiian farmers in the area. To provide information needed for successful management of the surface-water resources, the U.S. Geological Survey investigated the availability and distribution of natural low flow in Anahola Stream and also collected low-flow data in Goldfish Stream, a stream that discharges into Kaneha Reservoir, which served as a major collection point for the Makee diversion system. Biological surveys of Anahola Stream were conducted as part of a study to determine the distribution of native and nonnative aquatic stream fauna. Results of the biological surveys indicated the presence of the following native aquatic species in Anahola Stream: ʻoʻopu ʻakupa (Sandwich Island sleeper) and ʻoʻopu naniha (Tear-drop goby) in the lower stream reaches surveyed; and ʻoʻopu nākea (Pacific river goby), ʻoʻopu nōpili (Stimpson’s goby), and ʻōpae kalaʻole (Mountain shrimp) in the middle and upper stream reaches surveyed. Nonnative aquatic species were found in all of the surveyed stream reaches along Anahola Stream. The availability and distribution of natural low flow were determined using a combination of discharge measurements made from February 2011 to May 2012 at low-flow partial-record and seepage-run stations established at locations of interest along study-area streams. Upstream of the upper intake, the estimated natural (undiverted) median flow in Anahola Stream is 2.7 million gallons per day, and the flow is expected to be greater than or equal to 0.97 million gallons per day 95 percent of the time. About 0.7 mile upstream of the lower intake and downstream from the confluence with Keaʻoʻopu Stream, the estimated natural (undiverted) median flow in Anahola Stream is 6.3 million gallons per day, and the flow is expected to be greater than or equal to 2.7 million gallons per day 95 percent of the time. In Goldfish Stream, about 0.4 mile upstream from the point of discharge into Kaneha Reservoir, the estimated natural median flow is 0.54 million gallons per day, and the flow is expected to be greater than or equal to 0.23 million gallons per day 95 percent of the time. The discharge estimates are representative of low-flow conditions in the study-area streams, and they are applicable to the base period (water years 1961–2011) over which they have been computed. The distribution of natural low flow in Anahola Stream was characterized through data collected during wet- and dry-season seepage runs. Seepage-run results show that Anahola Stream was generally a gaining stream under natural low-flow conditions. During the wet-season seepage run, Anahola Stream at the station located upstream of tributary Kaʻalula Stream had more than five times the flow that was measured upstream from the upper intake. The estimated total gain (including tributary inflow) in the 6.1-mile seepage-run reach was 6.97 million gallons per day; about 42 percent of that gain was groundwater discharge to the main channel of Anahola Stream. During the dry-season seepage run, about 34 percent of the estimated total gain of 3.93 million gallons per day in the same seepage-run reach was groundwater discharge to the main channel of Anahola Stream. A 15-percent seepage loss was estimated in a 0.3-mile reach downstream from the confluence of Anahola and Keaʻoʻopu Streams. The report summarizes scenarios that describe (1) surface-water availability under regulated conditions of Anahola Stream if the upper and lower intakes are restored in the future; and (2) amount of flow available for agricultural use at the upper intake under a variety of potential instream-flow standards that may be established by the State of Hawaiʻi for the protection of instream uses.

Low-flow profiles of the upper Oconee River and tributaries in Georgia

USGS Publications Warehouse

Carter, R.F.; Hopkins, E.H.; Perlman, H.A.

1988-01-01

Low flow information is provided for use in an evaluation of the capacity of streams to permit withdrawals or to accept waste loads without exceeding the limits of State water quality standards. The purpose of this report is to present the results of a compilation of available low flow data in the form of tables and ' 7Q10 flow profiles ' (minimum average flow for 7 consecutive days with a 10-yr recurrence interval)(7Q10 flow plotted against distance along a stream channel) for all streams reaches of the Upper Oconee River and tributaries in Georgia where sufficient data of acceptable accuracy are available. Drainage area profiles are included for all stream basins larger than 5 sq mi, except for those in a few remote areas. This report is the second in a series of reports that will cover all stream basins north of the Fall Line in Georgia. It includes the Oconee River basin down to and including Camp Creek at stream mile 134.53, Town Creek in Baldwin and Hancock Counties down to County Road 213-141, and Buffalo Creek in Hancock County down to the Hancock-Washington County line. Flow records were not adjusted for diversions or other factors that cause measured flows to represent other than natural flow conditions. The 7-day minimum flow profile was omitted for stream reaches where natural flow was known to be altered significantly. (Lantz-PTT)

Combined effects of hydrologic alteration and cyprinid fish in mediating biogeochemical processes in a Mediterranean stream.

PubMed

Rubio-Gracia, Francesc; Almeida, David; Bonet, Berta; Casals, Frederic; Espinosa, Carmen; Flecker, Alexander S; García-Berthou, Emili; Martí, Eugènia; Tuulaikhuu, Baigal-Amar; Vila-Gispert, Anna; Zamora, Lluis; Guasch, Helena

2017-12-01

Flow regimes are important drivers of both stream community and biogeochemical processes. However, the interplay between community and biogeochemical responses under different flow regimes in streams is less understood. In this study, we investigated the structural and functional responses of periphyton and macroinvertebrates to different densities of the Mediterranean barbel (Barbus meridionalis, Cyprinidae) in two stream reaches differing in flow regime. The study was conducted in Llémena Stream, a small calcareous Mediterranean stream with high nutrient levels. We selected a reach with permanent flow (permanent reach) and another subjected to flow regulation (regulated reach) with periods of flow intermittency. At each reach, we used in situ cages to generate 3 levels of fish density. Cages with 10 barbels were used to simulate high fish density (>7indm -2 ); cages with open sides were used as controls (i.e. exposed to actual fish densities of each stream reach) thus having low fish density; and those with no fish were used to simulate the disappearance of fish that occurs with stream drying. Differences in fish density did not cause significant changes in periphyton biomass and macroinvertebrate density. However, phosphate uptake by periphyton was enhanced in treatments lacking fish in the regulated reach with intermittent flow but not in the permanent reach, suggesting that hydrologic alteration hampers the ability of biotic communities to compensate for the absence of fish. This study indicates that fish density can mediate the effects of anthropogenic alterations such as flow intermittence derived from hydrologic regulation on stream benthic communities and associated biogeochemical processes, at least in eutrophic streams. Copyright © 2017. Published by Elsevier B.V.

Floods on small streams in Texas

USGS Publications Warehouse

Ruggles, Frederick H.

1966-01-01

The first streamflow station in Texas was established on the Rio Grande at El Paso on May 10, 1889. Sip,ce that time the systematic collection of streamflow data. has expanded. In 1915 the Texas Board of Water Engineers (now the Texas Water Development Board) entered into a cooperative agreement with the U. S. Geological Survey for the purpose of expanding the network of stream-gaging stations in Texas. Sites were selected for stream-gaging stations to obtain hydrologic data for water supply and flood control. Therefore, the stream-gaging stations were located principally on major streams. Today, after three-quarters of a century.of hydrologic data collection, peak discharge data on small streams are still deficient in Texas. The Geological Survey and the Texas Highway Department, therefore, have entered into a cooperative program to collect peak discharge data on small streams for the purpose of deriving flood-frequency data needed for the economical design of culverts and small bridges.

The Dependence of the Peak Velocity of High-Speed Solar Wind Streams as Measured in the Ecliptic by ACE and the STEREO satellites on the Area and Co-latitude of Their Solar Source Coronal Holes.

PubMed

Hofmeister, Stefan J; Veronig, Astrid; Temmer, Manuela; Vennerstrom, Susanne; Heber, Bernd; Vršnak, Bojan

2018-03-01

We study the properties of 115 coronal holes in the time range from August 2010 to March 2017, the peak velocities of the corresponding high-speed streams as measured in the ecliptic at 1 AU, and the corresponding changes of the Kp index as marker of their geoeffectiveness. We find that the peak velocities of high-speed streams depend strongly on both the areas and the co-latitudes of their solar source coronal holes with regard to the heliospheric latitude of the satellites. Therefore, the co-latitude of their source coronal hole is an important parameter for the prediction of the high-speed stream properties near the Earth. We derive the largest solar wind peak velocities normalized to the coronal hole areas for coronal holes located near the solar equator and that they linearly decrease with increasing latitudes of the coronal holes. For coronal holes located at latitudes ≳ 60°, they turn statistically to zero, indicating that the associated high-speed streams have a high chance to miss the Earth. Similarly, the Kp index per coronal hole area is highest for the coronal holes located near the solar equator and strongly decreases with increasing latitudes of the coronal holes. We interpret these results as an effect of the three-dimensional propagation of high-speed streams in the heliosphere; that is, high-speed streams arising from coronal holes near the solar equator propagate in direction toward and directly hit the Earth, whereas solar wind streams arising from coronal holes at higher solar latitudes only graze or even miss the Earth.

Morphological divergence and flow-induced phenotypic plasticity in a native fish from anthropogenically altered stream habitats.

PubMed

Franssen, Nathan R; Stewart, Laura K; Schaefer, Jacob F

2013-11-01

Understanding population-level responses to human-induced changes to habitats can elucidate the evolutionary consequences of rapid habitat alteration. Reservoirs constructed on streams expose stream fishes to novel selective pressures in these habitats. Assessing the drivers of trait divergence facilitated by these habitats will help identify evolutionary and ecological consequences of reservoir habitats. We tested for morphological divergence in a stream fish that occupies both stream and reservoir habitats. To assess contributions of genetic-level differences and phenotypic plasticity induced by flow variation, we spawned and reared individuals from both habitats types in flow and no flow conditions. Body shape significantly and consistently diverged in reservoir habitats compared with streams; individuals from reservoirs were shallower bodied with smaller heads compared with individuals from streams. Significant population-level differences in morphology persisted in offspring but morphological variation compared with field-collected individuals was limited to the head region. Populations demonstrated dissimilar flow-induced phenotypic plasticity when reared under flow, but phenotypic plasticity in response to flow variation was an unlikely explanation for observed phenotypic divergence in the field. Our results, together with previous investigations, suggest the environmental conditions currently thought to drive morphological change in reservoirs (i.e., predation and flow regimes) may not be the sole drivers of phenotypic change.

Magnitude of flood flows for selected annual exceedance probabilities for streams in Massachusetts

USGS Publications Warehouse

Zarriello, Phillip J.

2017-05-11

The U.S. Geological Survey, in cooperation with the Massachusetts Department of Transportation, determined the magnitude of flood flows at selected annual exceedance prob­abilities (AEPs) at streamgages in Massachusetts and from these data developed equations for estimating flood flows at ungaged locations in the State. Flood magnitudes were deter­mined for the 50-, 20-, 10-, 4-, 2-, 1-, 0.5-, and 0.2-percent AEPs at 220 streamgages, 125 of which are in Massachusetts and 95 are in the adjacent States of Connecticut, New Hamp­shire, New York, Rhode Island, and Vermont. AEP flood flows were computed for streamgages using the expected moments algorithm weighted with a recently computed regional skew­ness coefficient for New England.Regional regression equations were developed to estimate the magnitude of floods for selected AEP flows at ungaged sites from 199 selected streamgages and for 60 potential explanatory basin characteristics. AEP flows for 21 of the 125 streamgages in Massachusetts were not used in the final regional regression analysis, primarily because of regulation or redundancy. The final regression equations used general­ized least squares methods to account for streamgage record length and correlation. Drainage area, mean basin elevation, and basin storage explained 86 to 93 percent of the variance in flood magnitude from the 50- to 0.2-percent AEPs, respec­tively. The estimates of AEP flows at streamgages can be improved by using a weighted estimate that is based on the magnitude of the flood and associated uncertainty from the at-site analysis and the regional regression equations. Weighting procedures for estimating AEP flows at an ungaged site on a gaged stream also are provided that improve estimates of flood flows at the ungaged site when hydrologic characteristics do not abruptly change.Urbanization expressed as the percentage of imperviousness provided some explanatory power in the regional regression; however, it was not statistically significant at the 95-percent confidence level for any of the AEPs examined. The effect of urbanization on flood flows indicates a complex interaction with other basin characteristics. Another complicating factor is the assumption of stationarity, that is, the assumption that annual peak flows exhibit no significant trend over time. The results of the analysis show that stationarity does not prevail at all of the streamgages. About 27 percent of streamgages in Massachusetts and about 42 percent of streamgages in adjacent States with 20 or more years of systematic record used in the study show a significant positive trend at the 95-percent confidence level. The remaining streamgages had both positive and negative trends, but the trends were not statistically significant. Trends were shown to vary over time. In particular, during the past decade (2004–2013), peak flows were persistently above normal, which may give the impression of positive trends. Only continued monitoring will provide the information needed to determine whether recent increases in annual peak flows are a normal oscillation or a true trend.The analysis used 37 years of additional data obtained since the last comprehensive study of flood flows in Massa­chusetts. In addition, new methods for computing flood flows at streamgages and regionalization improved estimates of flood magnitudes at gaged and ungaged locations and better defined the uncertainty of the estimates of AEP floods.

Low-flow characteristics of streams in the Puget Sound region, Washington

USGS Publications Warehouse

Hidaka, F.T.

1973-01-01

Periods of low streamflow are usually the most critical factor in relation to most water uses. The purpose of this report is to present data on low-flow characteristics of streams in the Puget Sound region, Washington, and to briefly explain some of the factors that influence low flow in the various basins. Presented are data on low-flow frequencies of streams in the Puget Sound region, as gathered at 150 gaging stations. Four indexes were computed from the flow-flow-frequency curves and were used as a basis to compare the low-flow characteristics of the streams. The indexes are the (1) low-flow-yield index, expressed in unit runoff per square mile; (2) base-flow index, or the ratio of the median 7-day low flow to the average discharge; (3) slope index, or slope of annual 7-day low-flow-frequency curve; and (4) spacing index, or spread between the 7-day and 183-day low-flow-frequency curves. The indexes showed a wide variation between streams due to the complex interrelation between climate, topography, and geology. The largest low-flow-yield indexes determined--greater than 1.5 cfs (cubic feet per second) per square mile--were for streams that head at high altitudes in the Cascade and Olympic Mountains and have their sources at glaciers. The smallest low-flow-yield indexes--less than 0.5 cfs per square mile--were for the small streams that drain the lowlands adjacent to Puget Sound. Indexes between the two extremes were for nonglacial streams that head at fairly high altitudes in areas of abundant precipitation. The base-flow index has variations that can be attributed to a basin's hydrogeology, with very little influence from climate. The largest base-flow indexes were obtained for streams draining permeable unconsolidated glacial and alluvial sediments in parts of the lowlands adjacent to Puget Sound. Large volume of ground water in these materials sustain flows during late summer. The smallest indexes were computed for streams draining areas underlain by relatively impermeable igneous, sedimentary, and metamorphic rocks or by relatively impermeable glacial till. Melt water from snow and ice influences the index for streams which originate at glaciers, and result in fairly large indexes--0.25 or greater. The slope index is influenced principally by the character of the geologic materials that underlie the basin. The largest slope indexes were computed for small streams that drain areas underlain by compact glacial till or consolidated sedimentary rocks. In contrast, lowland streams that flow through areas underlain by unconsolidated alluvia and glacial deposits have the smallest indexes. Small slope indexes also are characteristic of glacial streams and show the moderating effect of the snow and ice storage in the high mountain basins. The spacing indexes are similar to the slope indexes in that they are affected by the character of the geologic materials underlying a basin. The largest spacing indexes are characteristic of small streams whose basins are underlain by glacial till or by consolidated sedimentary rocks. The smallest indexes were computed for some lowland streams draining areas underlain by permeable glacial and alluvial sediments. The indexes do not appear to have a definite relation to each other. The low-flow-yield indexes are not related to either the slope or spacing indexes because snow and ice storage has a great influence on the low-flow-yield index, while the character of the geologic materials influences the slope and spacing indexes. A relation exists between the slope and spacing indexes but many anomalies occur that cannot be explained by the geology of the basins.

Mean flow field and surface heating produced by unequal shock interactions at hypersonic speeds

NASA Technical Reports Server (NTRS)

Birch, S. F.; Rudy, D. H.

1975-01-01

Mean velocity profiles were measured in a free shear layer produced by the interaction of two unequal strength shock waves at hypersonic free-stream Mach numbers. Measurements were made over a unit Reynolds number range of 3,770,000 per meter to 17,400,000 per meter based on the flow on the high velocity side of the shear layer. The variation in measured spreading parameters with Mach number for the fully developed flows is consistent with the trend of the available zero velocity ratio data when the Mach numbers for the data given in this study are taken to be characteristic Mach numbers based on the velocity difference across the mixing layer. Surface measurements in the shear-layer attachment region of the blunt-body model indicate peak local heating and static pressure consistent with other published data. Transition Reynolds numbers were found to be significantly lower than those found in previous data.

User's guide for a general purpose dam-break flood simulation model (K-634)

USGS Publications Warehouse

Land, Larry F.

1981-01-01

An existing computer program for simulating dam-break floods for forecast purposes has been modified with an emphasis on general purpose applications. The original model was formulated, developed and documented by the National Weather Service. This model is based on the complete flow equations and uses a nonlinear implicit finite-difference numerical method. The first phase of the simulation routes a flood wave through the reservoir and computes an outflow hydrograph which is the sum of the flow through the dam 's structures and the gradually developing breach. The second phase routes this outflow hydrograph through the stream which may be nonprismatic and have segments with subcritical or supercritical flow. The results are discharge and stage hydrographs at the dam as well as all of the computational nodes in the channel. From these hydrographs, peak discharge and stage profiles are tabulated. (USGS)

Identifying dissolved organic carbon sources at a gaged headwater catchment using FDOM sensors

NASA Astrophysics Data System (ADS)

Malzone, J. M.; Shanley, J. B.

2014-12-01

The United States Geological Survey's (USGS) W-9 gage at the headwaters of Sleepers River, Vermont has been monitored for dissolved organic carbon (DOC) concentration for more than 20 years. However, the sources of this DOC during base flow and hydrologic events remain unclear. The major objectives of this research were to identify sources of DOC during storm events and to explain the observed DOC-streamflow counterclockwise hysteresis during hydrologic events. Two main hypotheses to explain hysteresis during hydrologic events were tested: (1) distant headwater wetlands are the major DOC source, which lags behind peak flow due to travel time; and (2) the entire watershed contributes to the DOC at the gage, but the response of DOC lags behind the period when groundwater contributes most to streamflow. Sources of DOC were tracked using fluorescent dissolved organic matter (FDOM) sensors in surface water and groundwater wells. Wells were installed at four depths, 0.3, 0.6, 0.9, and 1.2 m, at four sites: a peaty low-gradient riparian area near the headwaters; a mid-hillslope area on a long hillslope mid-watershed; a near-stream area on a long hillslope mid-watershed; and a low-gradient tributary confluence area just above the gage. During storm events, FDOM and hydraulic head were measured at the nested groundwater wells. Samples for DOC analysis were also taken to determine the relationship between FDOM and DOC. Results suggest that both distant sources and the greater watershed played a role in the transport of DOC to the W-9 gage. Distant peaty sources dominated during large storms and contributed the highest surface water FDOM measurements. The peak FDOM at the gage was therefore best described as a result of transport. However, export from these distant sources terminated rapidly and did not explain continued elevated FDOM at the gage. Groundwater across the watershed exhibited hysteresis analogous to that in the stream itself, with FDOM peaking as head receded. As groundwater is recharged, the water table intersects more carbon rich soil layers. Pre-event water is flushed out first before event water mobilizes DOC, causing the groundwater hysteresis. High FDOM groundwater discharging to the stream likely sustained elevated FDOM at the gage. The gage hysteresis, therefore, seems to be a result of both hypotheses tested.

Evaluating the reliability of the stream tracer approach to characterize stream-subsurface water exchange

USGS Publications Warehouse

Harvey, Judson W.; Wagner, Brian J.; Bencala, Kenneth E.

1996-01-01

Stream water was locally recharged into shallow groundwater flow paths that returned to the stream (hyporheic exchange) in St. Kevin Gulch, a Rocky Mountain stream in Colorado contaminated by acid mine drainage. Two approaches were used to characterize hyporheic exchange: sub-reach-scale measurement of hydraulic heads and hydraulic conductivity to compute streambed fluxes (hydrometric approach) and reachscale modeling of in-stream solute tracer injections to determine characteristic length and timescales of exchange with storage zones (stream tracer approach). Subsurface data were the standard of comparison used to evaluate the reliability of the stream tracer approach to characterize hyporheic exchange. The reach-averaged hyporheic exchange flux (1.5 mL s−1 m−1), determined by hydrometric methods, was largest when stream base flow was low (10 L s−1); hyporheic exchange persisted when base flow was 10-fold higher, decreasing by approximately 30%. Reliability of the stream tracer approach to detect hyporheic exchange was assessed using first-order uncertainty analysis that considered model parameter sensitivity. The stream tracer approach did not reliably characterize hyporheic exchange at high base flow: the model was apparently more sensitive to exchange with surface water storage zones than with the hyporheic zone. At low base flow the stream tracer approach reliably characterized exchange between the stream and gravel streambed (timescale of hours) but was relatively insensitive to slower exchange with deeper alluvium (timescale of tens of hours) that was detected by subsurface measurements. The stream tracer approach was therefore not equally sensitive to all timescales of hyporheic exchange. We conclude that while the stream tracer approach is an efficient means to characterize surface-subsurface exchange, future studies will need to more routinely consider decreasing sensitivities of tracer methods at higher base flow and a potential bias toward characterizing only a fast component of hyporheic exchange. Stream tracer models with multiple rate constants to consider both fast exchange with streambed gravel and slower exchange with deeper alluvium appear to be warranted.

Identify temporal trend of air temperature and its impact on forest stream flow in Lower Mississippi River Alluvial Valley using wavelet analysis

USDA-ARS?s Scientific Manuscript database

Characterization of stream flow is essential to water resource management, water supply planning, environmental protection, and ecological restoration; while climate change can exacerbate stream flow and add instability to the flow. In this study, the wavelet analysis technique was employed to asse...

Flow regime alterations under changing climate in two river basins: Implications for freshwater ecosystems

USGS Publications Warehouse

Gibson, C.A.; Meyer, J.L.; Poff, N.L.; Hay, L.E.; Georgakakos, A.

2005-01-01

We examined impacts of future climate scenarios on flow regimes and how predicted changes might affect river ecosystems. We examined two case studies: Cle Elum River, Washington, and Chattahoochee-Apalachicola River Basin, Georgia and Florida. These rivers had available downscaled global circulation model (GCM) data and allowed us to analyse the effects of future climate scenarios on rivers with (1) different hydrographs, (2) high future water demands, and (3) a river-floodplain system. We compared observed flow regimes to those predicted under future climate scenarios to describe the extent and type of changes predicted to occur. Daily stream flow under future climate scenarios was created by either statistically downscaling GCMs (Cle Elum) or creating a regression model between climatological parameters predicted from GCMs and stream flow (Chattahoochee-Apalachicola). Flow regimes were examined for changes from current conditions with respect to ecologically relevant features including the magnitude and timing of minimum and maximum flows. The Cle Elum's hydrograph under future climate scenarios showed a dramatic shift in the timing of peak flows and lower low flow of a longer duration. These changes could mean higher summer water temperatures, lower summer dissolved oxygen, and reduced survival of larval fishes. The Chattahoochee-Apalachicola basin is heavily impacted by dams and water withdrawals for human consumption; therefore, we made comparisons between pre-large dam conditions, current conditions, current conditions with future demand, and future climate scenarios with future demand to separate climate change effects and other anthropogenic impacts. Dam construction, future climate, and future demand decreased the flow variability of the river. In addition, minimum flows were lower under future climate scenarios. These changes could decrease the connectivity of the channel and the floodplain, decrease habitat availability, and potentially lower the ability of the river to assimilate wastewater treatment plant effluent. Our study illustrates the types of changes that river ecosystems might experience under future climates. Copyright ?? 2005 John Wiley & Sons, Ltd.

The long term response of stream flow to climatic warming in headwater streams of interior Alaska

Treesearch

Jeremy B. Jones; Amanda J. Rinehart

2010-01-01

Warming in the boreal forest of interior Alaska will have fundamental impacts on stream ecosystems through changes in stream hydrology resulting from upslope loss of permafrost, alteration of availability of soil moisture, and the distribution of vegetation. We examined stream flow in three headwater streams of the Caribou-Poker Creeks Research Watershed (CPCRW) in...

Methods for estimating flow-duration curve and low-flow frequency statistics for ungaged locations on small streams in Minnesota

USGS Publications Warehouse

Ziegeweid, Jeffrey R.; Lorenz, David L.; Sanocki, Chris A.; Czuba, Christiana R.

2015-12-24

Equations developed in this study apply only to stream locations where flows are not substantially affected by regulation, diversion, or urbanization. All equations presented in this study will be incorporated into StreamStats, a web-based geographic information system tool developed by the U.S. Geological Survey. StreamStats allows users to obtain streamflow statistics, basin characteristics, and other information for user-selected locations on streams through an interactive map.

Quantifying spatial and temporal patterns of flow intermittency using spatially contiguous runoff data

NASA Astrophysics Data System (ADS)

Yu (于松延), Songyan; Bond, Nick R.; Bunn, Stuart E.; Xu, Zongxue; Kennard, Mark J.

2018-04-01

River channel drying caused by intermittent stream flow is a widely-recognized factor shaping stream ecosystems. There is a strong need to quantify the distribution of intermittent streams across catchments to inform management. However, observational gauge networks provide only point estimates of streamflow variation. Increasingly, this limitation is being overcome through the use of spatially contiguous estimates of the terrestrial water-balance, which can also assist in estimating runoff and streamflow at large-spatial scales. Here we proposed an approach to quantifying spatial and temporal variation in monthly flow intermittency throughout river networks in eastern Australia. We aggregated gridded (5 × 5 km) monthly water-balance data with a hierarchically nested catchment dataset to simulate catchment runoff accumulation throughout river networks from 1900 to 2016. We also predicted zero flow duration for the entire river network by developing a robust predictive model relating measured zero flow duration (% months) to environmental predictor variables (based on 43 stream gauges). We then combined these datasets by using the predicted zero flow duration from the regression model to determine appropriate 'zero' flow thresholds for the modelled discharge data, which varied spatially across the catchments examined. Finally, based on modelled discharge data and identified actual zero flow thresholds, we derived summary metrics describing flow intermittency across the catchment (mean flow duration and coefficient-of-variation in flow permanence from 1900 to 2016). We also classified the relative degree of flow intermittency annually to characterise temporal variation in flow intermittency. Results showed that the degree of flow intermittency varied substantially across streams in eastern Australia, ranging from perennial streams flowing permanently (11-12 months) to strongly intermittent streams flowing 4 months or less of year. Results also showed that the temporal extent of flow intermittency varied dramatically inter-annually from 1900 to 2016, with the proportion of intermittent (weakly and strongly intermittent) streams ranging in length from 3% to nearly 100% of the river network, but there was no evidence of an increasing trend towards flow intermittency over this period. Our approach to generating spatially explicit and catchment-wide estimates of streamflow intermittency can facilitate improved ecological understanding and management of intermittent streams in Australia and around the world.

Resonance and streaming of armored microbubbles

NASA Astrophysics Data System (ADS)

Spelman, Tamsin; Bertin, Nicolas; Stephen, Olivier; Marmottant, Philippe; Lauga, Eric

2015-11-01

A new experimental technique involves building a hollow capsule which partially encompasses a microbubble, creating an ``armored microbubble'' with long lifespan. Under acoustic actuation, such bubble produces net streaming flows. In order to theoretically model the induced flow, we first extend classical models of free bubbles to describe the streaming flow around a spherical body for any known axisymmetric shape oscillation. A potential flow model is then employed to determine the resonance modes of the armored microbubble. We finally use a more detailed viscous model to calculate the surface shape oscillations at the experimental driving frequency, and from this we predict the generated streaming flows.

Slip stream apparatus and method for treating water in a circulating water system

DOEpatents

Cleveland, J.R.

1997-03-18

An apparatus is described for treating water in a circulating water system that has a cooling water basin which includes a slip stream conduit in flow communication with the circulating water system, a source of acid solution in flow communication with the slip stream conduit, and a decarbonator in flow communication with the slip stream conduit and the cooling water basin. In use, a slip stream of circulating water is drawn from the circulating water system into the slip stream conduit of the apparatus. The slip stream pH is lowered by contact with an acid solution provided from the source thereof. The slip stream is then passed through a decarbonator to form a treated slip stream, and the treated slip stream is returned to the cooling water basin. 4 figs.

Perched groundwater-surface interactions and their consequences in stream flow generation in a semi-arid headwater catchment

NASA Astrophysics Data System (ADS)

Molenat, Jerome; Bouteffeha, Maroua; Raclot, Damien; Bouhlila, Rachida

2013-04-01

In semi-arid headwater catchment, it is usually admitted that stream flow comes predominantly from Hortonian overland flow (infiltration excess overland flow). Consequently, subsurface flow processes, and especially perched or shallow groundwater flow, have not been studied extensively. Here we made the assumption that perched groundwater flow could play a significant role in stream flow generation in semi-arid catchment. To test this assumption, we analyzed stream flow time series of a headwater catchment in the Tunisian Cap Bon region and quantified the flow fraction coming from groundwater discharge and that from overland flow. Furthermore, the dynamics of the perched groundwater was analyzed, by focusing on the different perched groundwater-surface interaction processes : diffuse and local infiltration, diffuse exfiltration, and direct groundwater discharge to the stream channel. This work is based on the 2.6 km² Kamech catchment (Tunisia), which belongs to the long term Mediterranean hydrological observatory OMERE (Voltz and Albergel, 2002). Results show that even though Hortonian overland flow was the main hydrological process governing the stream flow generation, groundwater discharge contribution to the stream channel annually accounted for from 10% to 20 % depending on the year. Furthermore, at some periods, rising of groundwater table to the soil surface in bottom land areas provided evidences of the occurrence of saturation excess overland flow processes during some storm events. Reference Voltz , M. and Albergel , J., 2002. OMERE : Observatoire Méditerranéen de l'Environnement Rural et de l'Eau - Impact des actions anthropiques sur les transferts de masse dans les hydrosystèmes méditerranéens ruraux. Proposition d'Observatoire de Recherche en Environnement, Ministère de la Recherche.

Comparison of flood frequency estimates from synthetic and observed data on small drainage areas in Mississippi

USGS Publications Warehouse

Colson, B.E.

1986-01-01

In 1964 the U.S. Geological Survey in Mississippi expanded the small stream gaging network for collection of rainfall and runoff data to 92 stations. To expedite availability of flood frequency information a rainfall-runoff model using available long-term rainfall data was calibrated to synthesize flood peaks. Results obtained from observed annual peak flow data for 51 sites having 16 yr to 30 yr of annual peaks are compared with the synthetic results. Graphical comparison of the 2, 5, 10, 25, 50, and 100-year flood discharges indicate good agreement. The root mean square error ranges from 27% to 38% and the synthetic record bias from -9% to -18% in comparison with the observed record. The reduced variance in the synthetic results is attributed to use of only four long-term rainfall records and model limitations. The root mean square error and bias is within the accuracy considered to be satisfactory. (Author 's abstract)

Availability and Distribution of Base Flow in Lower Honokohau Stream, Island of Maui

USGS Publications Warehouse

Fontaine, Richard A.

2003-01-01

Honokohau Stream is one of the few perennial streams in the Lahaina District of West Maui. Current Honokohau water-use practices often lead to conflicts among water users, which are most evident during periods of base flow. To better manage the resource, data are needed that describe the availability and distribution of base flow in lower Honokohau Stream and how base flow is affected by streamflow diversion and return-flow practices. Flow-duration discharges for percentiles ranging from 50 to 95 percent were estimated at 13 locations on lower Honokohau Stream using data from a variety of sources. These sources included (1) available U.S. Geological Survey discharge data, (2) published summaries of Maui Land & Pineapple Company, Inc. diversion and water development-tunnel data, (3) seepage run and low-flow partial-record discharge measurements made for this study, and (4) current (2003) water diversion and return-flow practices. These flow-duration estimates provide a detailed characterization of the distribution and availability of base flow in lower Honokohau Stream. Estimates of base-flow statistics indicate the significant effect of Honokohau Ditch diversions on flow in the stream. Eighty-six percent of the total flow upstream from the ditch is diverted from the stream. Immediately downstream from the diversion dam there is no flow in the stream 91.2 percent of the time, except for minor leakage through the dam. Flow releases at the Taro Gate, from Honokohau Ditch back into the stream, are inconsistent and were found to be less than the target release of 1.55 cubic feet per second on 9 of the 10 days on which measurements were made. Previous estimates of base-flow availability downstream from the Taro Gate release range from 2.32 to 4.6 cubic feet per second (1.5 to 3.0 million gallons per day). At the two principal sites where water is currently being diverted for agricultural use in the valley (MacDonald's and Chun's Dams), base flows of 2.32 cubic feet per second (1.5 million gallons per day) are available more than 95 percent of the time at MacDonald's Dam and 80 percent of the time at Chun's Dam. Base flows of 4.6 cubic feet per second (3.0 million gallons per day) are available 65 and 56 percent of the time, respectively. A base-flow water-accounting model was developed to estimate how flow-duration discharges for 13 sites on Honokohau Stream would change in response to a variety of flow release and diversion practices. A sample application of the model indicates that there is a 1 to 1 relation between changes in flow release rates at the Taro Gate and base flow upstream from MacDonald's Dam. At Chun's Dam the relation between Taro Gate releases and base flow varies with flow-duration percentiles. At the 95th and 60th percentiles, differences in base flow at Chun's Dam would equal about 50 and 90 percent of the change at the Taro Gate.

Characterization and classification of invertebrates as indicators of flow permanence in headwater streams

EPA Science Inventory

Headwater streams represent a large proportion of river networks and many have temporary flow. Litigation has questioned whether these streams are jurisdictional under the Clean Water Act. Our goal was to identify indicators of flow permanence by comparing invertebrate assemblage...

Water Resources Data, Florida, Water Year 2003, Volume 1A: Northeast Florida Surface Water

USGS Publications Warehouse

,

2004-01-01

Water resources data for the 2003 water year in Florida consist of continuous or daily discharge for 385 streams, periodic discharge for 13 streams, continuous or daily stage for 255 streams, periodic stage for 13 streams, peak stage and discharge for 36 streams; continuous or daily elevations for 13 lakes, periodic elevations for 46 lakes; continuous ground-water levels for 441 wells, periodic ground-water levels for 1,227 wells; quality-of-water data for 133 surface-water sites and 308 wells. The data for northeast Florida include continuous or daily discharge for 138 streams, periodic discharge for 3 streams, continuous or daily stage for 61 streams, periodic stage for 0 streams; peak stage and discharge for 0 streams; continuous or daily elevations for 9 lakes, periodic elevations for 20 lakes; continuous ground water levels for 73 wells, periodic groundwater levels for 543 wells; quality-of-water data for 43 surface-water sites and 115 wells. These data represent the National Water Data System records collected by the U.S. Geological Survey and cooperating local, State and Federal agencies in Florida.

Water Resources Data, Florida, Water Year 2003, Volume 1B: Northeast Florida Ground Water

USGS Publications Warehouse

George, H.G.; Nazarian, A.P.; Dickerson, S.M.

2004-01-01

Water resources data for the 2003 water year in Florida consist of continuous or daily discharge for 385 streams, periodic discharge for 13 streams, continuous or daily stage for 255 streams, periodic stage for 13 streams, peak stage and discharge for 36 streams; continuous or daily elevations for 13 lakes, periodic elevations for 46 lakes; continuous ground-water levels for 441 wells, periodic ground-water levels for 1,227 wells; quality-of-water data for 133 surface-water sites and 308 wells. The data for northeast Florida include continuous or daily discharge for 138 streams, periodic discharge for 3 streams, continuous or daily stage for 61 streams, periodic stage for 0 streams; peak stage and discharge for 0 streams; continuous or daily elevations for 9 lakes, periodic elevations for 20 lakes; continuous ground water levels for 73 wells, periodic groundwater levels for 543 wells; quality-of-water data for 43 surface-water sites and 115 wells. These data represent the National Water Data System records collected by the U.S. Geological Survey and cooperating local, State and Federal agencies in Florida.

Water quality, streamflow conditions, and annual flow-duration curves for streams of the San Juan–Chama Project, southern Colorado and northern New Mexico, 1935-2010

USGS Publications Warehouse

Falk, Sarah E.; Anderholm, Scott K.; Hafich, Katya A.

2013-01-01

The Albuquerque–Bernalillo County Water Utility Authority supplements the municipal water supply for the Albuquerque metropolitan area, in central New Mexico, with water diverted from the Rio Grande. Water diverted from the Rio Grande for municipal use is derived from the San Juan–Chama Project, which delivers water from streams in the southern San Juan Mountains in the Colorado River Basin in southern Colorado to the Rio Chama watershed and the Rio Grande Basin in northern New Mexico. The U.S. Geological Survey, in cooperation with Albuquerque–Bernalillo County Water Utility Authority, has compiled historical streamflow and water-quality data and collected new water-quality data to characterize the water quality and streamflow conditions and annual flow variability, as characterized by annual flow-duration curves, of streams of the San Juan–Chama Project. Nonparametric statistical methods were applied to calculate annual and monthly summary statistics of streamflow, trends in streamflow conditions were evaluated with the Mann–Kendall trend test, and annual variation in streamflow conditions was evaluated with annual flow-duration curves. The study area is located in northern New Mexico and southern Colorado and includes the Rio Blanco, Little Navajo River, and Navajo River, tributaries of the San Juan River in the Colorado River Basin located in the southern San Juan Mountains, and Willow Creek and Horse Lake Creek, tributaries of the Rio Chama in the Rio Grande Basin. The quality of water in the streams in the study area generally varied by watershed on the basis of the underlying geology and the volume and source of the streamflow. Water from the Rio Blanco and Little Navajo River watersheds, primarily underlain by volcanic deposits, volcaniclastic sediments and landslide deposits derived from these materials, was compositionally similar and had low specific-conductance values relative to the other streams in the study area. Water from the Navajo River, Horse Lake Creek, and Willow Creek watersheds, which are underlain mostly by Cretaceous-aged marine shale, was compositionally similar and had large concentrations of sulfate relative to the other streams in the study area, though the water from the Navajo River had lower specific-conductance values than did the water from Horse Lake Creek above Heron Reservoir and Willow Creek above Azotea Creek. Generally, surface-water quality varied with streamflow conditions throughout the year. Streamflow in spring and summer is generally a mixture of base flow (the component of streamflow derived from groundwater discharged to the stream channel) diluted with runoff from snowmelt and precipitation events, whereas streamflow in fall and winter is generally solely base flow. Major- and trace-element concentrations in the streams sampled were lower than U.S. Environmental Protection Agency primary and secondary drinking-water standards and New Mexico Environment Department surface-water standards for the streams. In general, years with increased annual discharge, compared to years with decreased annual discharge, had a smaller percentage of discharge in March, a larger percentage of discharge in June, an interval of discharge derived from snowmelt runoff that occurred later in the year, and a larger discharge in June. Additionally, years with increased annual discharge generally had a longer duration of runoff, and the streamflow indicators occurred at dates later in the year than the years with less snowmelt runoff. Additionally, the seasonal distribution of streamflow was more strongly controlled by the change in the amount of annual discharge than by changes in streamflow over time. The variation of streamflow conditions over time at one streamflow-gaging station in the study area, Navajo River at Banded Peak Ranch, was not significantly monotonic over the period of record with a Kendall’s tau of 0.0426 and with a p-value of 0.5938 for 1937 to 2009 (a trend was considered statistically significant at a p-value ≤ 0.05). There was a relation, however, such that annual discharge was generally lower than the median during a negative Pacific Decadal Oscillation interval and higher than the median during a positive Pacific Decadal Oscillation interval. Streamflow conditions at Navajo River at Banded Peak Ranch varied nonmonotonically over time and were likely a function of complex climate pattern interactions. Similarly, the monthly distribution of streamflow varied nonmonotonically over time and was likely a function of complex climate pattern interactions that cause variation over time. Study results indicated that the median of the sum of the streamflow available above the minimum monthly bypass requirement from Rio Blanco, Little Navajo River, and Navajo River was 126,240 acre-feet. The results also indicated that diversion of water for the San Juan–Chama Project has been possible for most months of most years.

Bed-material entrainment and associated transportation infrastructure problems in streams of the Edwards Plateau, central Texas

USGS Publications Warehouse

Heitmuller, Franklin T.; Asquith, William H.

2008-01-01

The Texas Department of Transportation commonly builds and maintains low-water crossings (LWCs) over streams in the Edwards Plateau in Central Texas. LWCs are low-height structures, typically constructed of concrete and asphalt, that provide acceptable passage over seasonal rivers or streams with relatively low normal-depth flow. They are designed to accommodate flow by roadway overtopping during high-flow events. The streams of the Edwards Plateau are characterized by cobble- and gravel-sized bed material and highly variable flow regimes. Low base flows that occur most of the time occasionally are interrupted by severe floods. The floods entrain and transport substantial loads of bed material in the stream channels. As a result, LWCs over streams in the Edwards Plateau are bombarded and abraded by bed material during floods and periodically must be maintained or even replaced.

Comparison of peak discharges among sites with and without valley fills for the July 8-9, 2001 flood in the headwaters of Clear Fork, Coal River basin, mountaintop coal-mining region, southern West Virginia

USGS Publications Warehouse

Wiley, Jeffrey B.; Brogan, Freddie D.

2003-01-01

The effects of mountaintop-removal mining practices on the peak discharges of streams were investigated in six small drainage basins within a 7-square-mile area in southern West Virginia. Two of the small basins had reclaimed valley fills, one basin had reclaimed and unreclaimed valley fills, and three basins did not have valley fills. Indirect measurements of peak discharge for the flood of July 8-9, 2001, were made at six sites on streams draining the small basins. The sites without valley fills had peak discharges with 10- to 25-year recurrence intervals, indicating that rainfall intensities and totals varied among the study basins. The flood-recurrence intervals for the three basins with valley fills were determined as though the peak discharges were those from rural streams without the influence of valley fills, and ranged from less than 2 years to more than 100 years.

Artificial intelligence techniques coupled with seasonality measures for hydrological regionalization of Q90 under Brazilian conditions

NASA Astrophysics Data System (ADS)

Beskow, Samuel; de Mello, Carlos Rogério; Vargas, Marcelle M.; Corrêa, Leonardo de L.; Caldeira, Tamara L.; Durães, Matheus F.; de Aguiar, Marilton S.

2016-10-01

Information on stream flows is essential for water resources management. The stream flow that is equaled or exceeded 90% of the time (Q90) is one the most used low stream flow indicators in many countries, and its determination is made from the frequency analysis of stream flows considering a historical series. However, stream flow gauging network is generally not spatially sufficient to meet the necessary demands of technicians, thus the most plausible alternative is the use of hydrological regionalization. The objective of this study was to couple the artificial intelligence techniques (AI) K-means, Partitioning Around Medoids (PAM), K-harmonic means (KHM), Fuzzy C-means (FCM) and Genetic K-means (GKA), with measures of low stream flow seasonality, for verification of its potential to delineate hydrologically homogeneous regions for the regionalization of Q90. For the performance analysis of the proposed methodology, location attributes from 108 watersheds situated in southern Brazil, and attributes associated with their seasonality of low stream flows were considered in this study. It was concluded that: (i) AI techniques have the potential to delineate hydrologically homogeneous regions in the context of Q90 in the study region, especially the FCM method based on fuzzy logic, and GKA, based on genetic algorithms; (ii) the attributes related to seasonality of low stream flows added important information that increased the accuracy of the grouping; and (iii) the adjusted mathematical models have excellent performance and can be used to estimate Q90 in locations lacking monitoring.

A hydrometric and geochemical approach to test the transmissivity feedback hypothesis during snowmelt

USGS Publications Warehouse

Kendall, K.A.; Shanley, J.B.; McDonnell, Jeffery J.

1999-01-01

To test the transmissivity feedback hypothesis of runoff generation, surface and subsurface waters were monitored and sampled during the 1996 snowmelt at various topographic positions in a 41 ha forested headwater catchment at Sleepers River, Vermont. Two conditions that promote transmissivity feedback existed in the catchment during the melt period. First, saturated hydraulic conductivity increased toward land surface, from a geometric mean of 3.6 mm h-1 in glacial till to 25.6 mm h-1 in deep soil to 54.0 mm h-1 in shallow soil. Second, groundwater levels rose to within 0.3 m of land surface at all riparian sites and most hillslope sites at peak melt. The importance of transmissivity feedback to streamflow generation was tested at the catchment scale by examination of physical and chemical patterns of groundwater in near-stream (discharge) and hillslope (recharge/lateral flow) zones, and within a geomorphic hollow (convergent flow). The presence of transmissivity feedback was supported by the abrupt increase in streamflow as the water table rose into the surficial, transmissive zone; a flattening of the groundwater level vs. streamflow curve occurred at most sites. This relation had a clockwise hysteresis (higher groundwater level for given discharge on rising limb than at same discharge on falling limb) at riparian sites, suggesting that the riparian zone was the dominant source area during the rising limb of the melt hydrograph. Hysteresis was counterclockwise at hillslope sites, suggesting that hillslope drainage controlled the snowmelt recession. End member mixing analysis using Ca, Mg, Na, dissolved organic carbon (DOC), and Si showed that stream chemistry could be explained as a two-component mixture of groundwater high in base cations and an O-horizon/overland flow water high in DOC. The dominance of shallow flow paths during events was indicated by the high positive correlation of DOC with streamflow (r2 = 0.82). Despite the occurrence of transmissivity feedback, hillslope till and soil water were ruled out as end members primarily because their distinctive high-Si composition had little or no effect on streamwater composition. Till water from the geomorphic hollow had a chemistry very close to streamwater base flow, and may represent the base flow end member better than the more concentrated riparian groundwater. During snowmelt, streamwater composition shifted as this base flow was diluted - not by shallow groundwater from the hillslope, but rather by a more surficial O-horizon/overland flow water.Surface and subsurface waters were analyzed to test the transmissivity feedback of runoff generation during the 1996 snowmelt in a catchment at Sleepers River, Vermont. The importance of transmissivity feedback to stream flow generation was tested by examination of physical and chemical patterns of groundwater in near-stream and hillslope zones within a geomorphic hollow. End member mixing analysis of Ca, Mg, Na, dissolved organic carbon (DOC), and Si showed that stream chemistry could be explained as a two-component mixture of groundwater high in base cations and an O-horizon/overland flow water high in DOC. The dominance of shallow water paths during the events was indicated by the high positive correlation of DOC with streamflow (r2 = 0.82).

Sources and transformations of nitrate from streams draining varying land uses: Evidence from dual isotope analysis

USGS Publications Warehouse

Burns, Douglas A.; Boyer, E.W.; Elliott, E.M.; Kendall, C.

2009-01-01

Knowledge of key sources and biogeochemical processes that affect the transport of nitrate (NO3-) in streams can inform watershed management strategies for controlling downstream eutrophication. We applied dual isotope analysis of NO3- to determine the dominant sources and processes that affect NO3- concentrations in six stream/river watersheds of different land uses. Samples were collected monthly at a range of flow conditions for 15 mo during 2004-05 and analyzed for NO3- concentrations, ?? 15NNO3, and ??18ONO3. Samples from two forested watersheds indicated that NO3- derived from nitrification was dominant at baseflow. A watershed dominated by suburban land use had three ??18ONO3 values greater than +25???, indicating a large direct contribution of atmospheric NO 3- transported to the stream during some high flows. Two watersheds with large proportions of agricultural land use had many ??15NNO3 values greater than +9???, suggesting an animal waste source consistent with regional dairy farming practices. These data showed a linear seasonal pattern with a ??18O NO3:??15NNO3 of 1:2, consistent with seasonally varying denitrification that peaked in late summer to early fall with the warmest temperatures and lowest annual streamflow. The large range of ?? 15NNO3 values (10???) indicates that NO 3- supply was likely not limiting the rate of denitrification, consistent with ground water and/or in-stream denitrification. Mixing of two or more distinct sources may have affected the seasonal isotope patterns observed in these two agricultural streams. In a mixed land use watershed of large drainage area, none of the source and process patterns observed in the small streams were evident. These results emphasize that observations at watersheds of a few to a few hundred km2 may be necessary to adequately quantify the relative roles of various NO 3- transport and process patterns that contribute to streamflow in large basins. Copyright ?? 2009 by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America. All rights reserved.

Effects of chronic pollution and water flow intermittency on stream biofilms biodegradation capacity.

PubMed

Rožman, Marko; Acuña, Vicenç; Petrović, Mira

2018-02-01

A mesocosm case study was conducted to gain understanding and practical knowledge on biofilm emerging contaminants biodegradation capacity under stressor and multiple stressor conditions. Two real life scenarios: I) biodegradation in a pristine intermittent stream experiencing acute pollution and II) biodegradation in a chronically polluted intermittent stream, were examined via a multifactorial experiment using an artificial stream facility. Stream biofilms were exposed to different water flow conditions i.e. permanent and intermittent water flow. Venlafaxine, a readily biodegradable pharmaceutical was used as a measure of biodegradation capacity while pollution was simulated by a mixture of four emerging contaminants (erythromycin, sulfisoxazole, diclofenac and imidacloprid in addition to venlafaxine) in environmentally relevant concentrations. Biodegradation kinetics monitored via LC-MS/MS was established, statistically evaluated, and used to link biodegradation with stress events. The results suggest that the effects of intermittent flow do not hinder and may even stimulate pristine biofilm biodegradation capacity. Chronic pollution completely reduced biodegradation in permanent water flow experimental treatments while no change in intermittent streams was observed. A combined effect of water flow conditions and emerging contaminants exposure on biodegradation was found. The decrease in biodegradation due to exposure to emerging contaminants is significantly greater in streams with permanent water flow suggesting that the short and medium term biodegradation capacity in intermittent systems may be preserved or even greater than in perennial streams. Copyright © 2017 Elsevier Ltd. All rights reserved.

Capacitance probe for fluid flow and volume measurements

NASA Technical Reports Server (NTRS)

Arndt, G. Dickey (Inventor); Nguyen, Thanh X. (Inventor); Carl, James R. (Inventor)

1995-01-01

Method and apparatus for making measurements on fluids are disclosed, including the use of a capacitive probe for measuring the flow volume of a material within a flow stream. The capacitance probe has at least two elongate electrodes and, in a specific embodiment of the invention, has three parallel elongate electrodes with the center electrode being an extension of the center conductor of a co-axial cable. A conductance probe is also provided to provide more accurate flow volume data in response to conductivity of the material within the flow stream. A preferred embodiment of the present invention provides for a gas flow stream through a microgravity environment that allows for monitoring a flow volume of a fluid sample, such as a urine sample, that is entrained within the gas flow stream.

Capacitance Probe for Fluid Flow and Volume Measurements

NASA Technical Reports Server (NTRS)

Arndt, G. Dickey (Inventor); Nguyen, Thanh X. (Inventor); Carl, James R. (Inventor)

1997-01-01

Method and apparatus for making measurements on fluids are disclosed, including the use of a capacitive probe for measuring the flow volume of a material within a flow stream. The capacitance probe has at least two elongate electrodes and, in a specific embodiment of the invention, has three parallel elongate electrodes with the center electrode being an extension of the center conductor of a co-axial cable. A conductance probe is also provided to provide more accurate flow volume data in response to conductivity of the material within the flow stream. A preferred embodiment of the present invention provides for a gas flow stream through a micro-gravity environment that allows for monitoring a flow volume of a fluid sample, such as a urine sample, that is entrained within the gas flow stream.

Experimental study of a free turbulent shear flow at Mach 19 with electron-beam and conventional probes. [flow measurement

NASA Technical Reports Server (NTRS)

Harvey, W. P.; Hunter, W. D., Jr.

1975-01-01

An experimental study of the initial development region of a hypersonic turbulent free mixing layer was made. Data were obtained at three stations downstream of a M = 19 nozzle over a Reynolds range of 1.3 million to 3.3 million per meter and at a total temperature of about 1670 K. In general, good agreement was obtained between electron-beam and conventional probe measurements of local mean flow parameters. Measurements of fluctuating density indicated that peak root-mean-square (rms) levels are higher in the turbulent free mixing layer than in boundary layers for Mach numbers less than 9. The intensity of rms density fluctuations in the free stream is similar in magnitude to pressure fluctuations in high Mach number flows. Spectrum analyses of the measured fluctuating density through the shear layer indicate significant fluctuation energy at the lower frequencies (0.2 to 5 kHZ) which correspond to large-scale disturbances in the high-velocity region of the shear layer.

Mercury on the move during snowmelt in Vermont

USGS Publications Warehouse

Shanley, James B.; Schuster, P.F.; Reddy, M.M.; Roth, D.A.; Taylor, Howard E.; Aiken, G.

2002-01-01

Although mercury (Hg) emissions peaked in the United States over the last 20 to 40 years and are now declining, they remain well above natural background levels in soils and sediments. Only a small fraction of the Hg deposited from the atmosphere to the terrestrial landscape runs off in streamflow. However, some of this Hg is methylated in the environment and can potentially bioaccumulate to the top of food webs, posing a hazard to people who eat fish, especially children and pregnant women. What factors determine the amount of Hg that runs off in streams? During the 2000 snowmelt at Sleepers River in Vermont, strong correlations were found between dissolved and particulate mercury and the respective dissolved and particulate organic carbon fractions, even when data were pooled from 10 streams of diverse watershed size and land cover. Episodic export of particulate Hg during the highest flows appears to be the dominant mechanism of Hg movement.

Relationships between dissolved organic matter and discharge: New insights from in-situ measurements in a northern forested watershed

NASA Astrophysics Data System (ADS)

Pellerin, B. A.; Shanley, J. B.; Saraceno, J.; Aiken, G.; Sebestyen, S. D.; Bergamaschi, B. A.

2012-12-01

Quantifying the fundamental linkages between hydrology and dissolved organic matter (DOM) dynamics in streams and rivers is critical for understanding carbon loads, ecosystem food webs and metal transport. Accurately assessing this relationship is difficult, however, given that rapid changes in water flow paths and associated DOM sources are often not captured by traditional discrete sampling intervals of weeks to months. We explored DOM - discharge relationships at Sleepers River below a 40.5 hectare USGS research watershed in northern Vermont by making 30 minute chromophoric DOM fluorescence (FDOM) measurements in-situ since October 2008 along with periodic discrete sampling for dissolved organic carbon. There is a tight coupling between the timing of increases in FDOM and discharge at Sleepers during events, but the ratio of FDOM to discharge exhibited considerable variability across seasons and events, as did FDOM-discharge hysteresis (FDOM variously peaked 1-4 hours after streamflow). Discrete DOM quality indicators (spectral slope, fluorescence index, SUVA) indicate DOM was predominantly terrestrial at all but the lowest flows, highlighting the important role of DOM-rich terrestrial flow paths as the primary source of stream DOM. Our results suggest that changes in flow paths are likely to be the primary drivers of future changes in DOM transport from this site rather than changes in DOM quality. Overcoming significant challenges inherent in continuous sensor deployments in watersheds (e.g. ice cover, suspended particles, remote communication and power) will allow for new insights into watershed biogeochemistry.

Ecological studies of a regulated stream: Huntington River, Emery County, Utah

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

Winget, R.N.

1984-04-30

A 36.9 x 10/sup 6/ m/sup 3/ reservoir constructed on Huntington River, Emery County, Utah, resulted in changes in physical habitat, water quality, temperature, and flow regime. The greatest changes in physical habitat resulted from: (1) sediment additions from dam and road construction plus erosion of reservoir basin during filling; and (2) changing stream flow from a spring high runoff regime to a moderated flow regime. Elimination of spring nutrient concentration peaks and overall reduction of total dissolved nutrient availability in the river plus moderate reductions in pH were the most apparent water quality changes below the reservoir. Water temperaturemore » changes were an increased diurnal and seasonal constancy, summer depression, and winter elevation, generally limited to a 10-12 km reach below the dam. Physical and chemical changes altered macroinvertebrate community structure, with changes greatest near the dam and progressively less as distance downstream increased. Below the dam: (1) more environmentally tolerant taxa increased their dominance; (2) relative numbers of smaller sized individuals increased in relation to larger individuals; and (3) filter feeding, collector/gatherers, and scapers gained an advantage over shredders. Macroinvertebrate taxa with small instar larvae present from late summer to early fall were negatively impacted by the unnaturally high July and August flows. The reservoir became a physical barrier to downstream larval drift and upcanyon and downcanyon immigration of adults, resulting in reduced numbers of several species above and below the reservoir. 50 references, 12 figures, 3 tables.« less

Riparian indicators of flow frequency in a tropical montante stream network

Treesearch

Andrew S. Pike; Frederick N. Scatena

2010-01-01

Many field indicators have been used to approximate the magnitude and frequency of flows in a variety of streams and rivers, yet due to a scarcity of long-term flow records in tropical mountain streams, little to no work has been done to establish such relationships between field features and the flow regime in these environments. Furthermore, the transition between...

Low frequency vibration induced streaming in a Hele-Shaw cell

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

Costalonga, M., E-mail: maxime.costalonga@univ-paris-diderot.fr; Laboratoire Matière et Systèmes Complexes, UMR CNRS 7057, Université Paris Diderot, 10 rue Alice Domon et Léonie Duquet, 75205 Paris cedex 13; Brunet, P.

When an acoustic wave propagates in a fluid, it can generate a second order flow whose characteristic time is much longer than the period of the wave. Within a range of frequency between ten and several hundred Hz, a relatively simple and versatile way to generate streaming flow is to put a vibrating object in the fluid. The flow develops vortices in the viscous boundary layer located in the vicinity of the source of vibrations, leading in turn to an outer irrotational streaming called Rayleigh streaming. Because the flow originates from non-linear time-irreversible terms of the Navier-Stokes equation, this phenomenonmore » can be used to generate efficient mixing at low Reynolds number, for instance in confined geometries. Here, we report on an experimental study of such streaming flow induced by a vibrating beam in a Hele-Shaw cell of 2 mm span using long exposure flow visualization and particle-image velocimetry measurements. Our study focuses especially on the effects of forcing frequency and amplitude on flow dynamics. It is shown that some features of this flow can be predicted by simple scaling arguments and that this vibration-induced streaming facilitates the generation of vortices.« less

Study of Basin Recession Characteristics and Groundwater Storage Properties

NASA Astrophysics Data System (ADS)

Yen-Bo, Chen; Cheng-Haw, Lee

2017-04-01

Stream flow and groundwater storage are freshwater resources that human live on.In this study, we discuss southern area basin recession characteristics and Kao-Ping River basin groundwater storage, and hope to supply reference to Taiwan water resource management. The first part of this study is about recession characteristics. We apply Brutsaert (2008) low flow analysis model to establish two recession data pieces sifting models, including low flow steady period model and normal condition model. Within individual event analysis, group event analysis and southern area basin recession assessment, stream flow and base flow recession characteristics are parameterized. The second part of this study is about groundwater storage. Among main basin in southern Taiwan, there are sufficient stream flow and precipitation gaging station data about Kao-Ping River basin and extensive drainage data, and data about different hydrological characteristics between upstream and downstream area. Therefore, this study focuses on Kao-Ping River basin and accesses groundwater storage properties. Taking residue of groundwater volume in dry season into consideration, we use base flow hydrograph to access periodical property of groundwater storage, in order to establish hydrological period conceptual model. With groundwater storage and precipitation accumulative linearity quantified by hydrological period conceptual model, their periodical changing and alternation trend properties in each drainage areas of Kao-Ping River basin have been estimated. Results of this study showed that the recession time of stream flow is related to initial flow rate of the recession events. The recession time index is lower when the flow is stream flow, not base flow, and the recession time index is higher in low flow steady flow period than in normal recession condition. By applying hydrological period conceptual model, groundwater storage could explicitly be analyzed and compared with precipitation, by only using stream flow data. Keywords: stream flow, base flow, recession characteristics, groundwater storage

Comparison of Hydrologic and Water-Quality Characteristics of Two Native Tallgrass Prairie Streams with Agricultural Streams in Missouri and Kansas

USGS Publications Warehouse

Heimann, David C.

2009-01-01

This report presents the results of a study by the U.S. Geological Survey, in cooperation with the Missouri Department of Natural Resources, to analyze and compare hydrologic and water-quality characteristics of tallgrass prairie and agricultural basins located within the historical distribution of tallgrass prairie in Missouri and Kansas. Streamflow and water-quality data from two remnant, tallgrass prairie basins (East Drywood Creek at Prairie State Park, Missouri, and Kings Creek near Manhattan, Kansas) were compared to similar data from agricultural basins in Missouri and Kansas. Prairie streams, especially Kings Creek in eastern Kansas, received a higher percentage of base flow and a lower percentage of direct runoff than similar-sized agricultural streams in the region. A larger contribution of direct runoff from the agricultural streams made them much flashier than prairie streams. During 22 years of record, the Kings Creek base-flow component averaged 66 percent of total flow, but base flow was only 16 to 26 percent of flows at agricultural sites of various record periods. The large base-flow component likely is the result of greater infiltration of precipitation in prairie soils and the resulting greater contribution of groundwater to streamflow. The 1- and 3-day annual maximum flows were significantly greater at three agricultural sites than at Kings Creek. The effects of flashier agricultural streams on native aquatic biota are unknown, but may be an important factor in the sustainability of some native aquatic species. There were no significant differences in the distribution of dissolved-oxygen concentrations at prairie and agricultural sites, and some samples from most sites fell below the 5 milligrams per liter Missouri and Kansas standard for the protection of aquatic life. More than 10 percent of samples from the East Drywood Creek prairie stream were less than this standard. These data indicate low dissolved-oxygen concentrations during summer low-flow periods may be a natural phenomenon for small prairie streams in the Osage Plains. Nutrient concentrations including total nitrogen, ammonia, nitrate, and total phosphorus were significantly less in base-flow and runoff samples from prairie streams than from agricultural streams. The total nitrogen concentration at all sites other than one of two prairie sampling sites were, on occasion, above the U.S. Environmental Protection Agency recommended criterion for total nitrogen for the prevention of nutrient enrichment, and typically were above this recommended criterion in runoff samples at all sites. Nitrate and total phosphorus concentrations in samples from the prairie streams generally were below the U.S. Environmental Protection Agency recommended nutrient criteria in base-flow and runoff samples, whereas samples from agricultural sites generally were below the criteria in base-flow samples and generally above in runoff samples. The lower concentrations of nutrient species in prairie streams is likely because prairies are not fertilized like agricultural basins and prairie basins are able to retain nutrients better than agricultural basins. This retention is enhanced by increased infiltration of precipitation into the prairie soils, decreased surface runoff, and likely less erosion than in agricultural basins. Streamflow in the small native prairie streams had more days of zero flow and lower streamflow yields than similar-sized agricultural streams. The prairie streams were at zero flow about 50 percent of the time, and the agricultural streams were at zero flow 25 to 35 percent of the time. Characteristics of the prairie basins that could account for the greater periods of zero flow and lower yields when compared to agricultural streams include greater infiltration, greater interception and evapotranspiration, shallower soils, and possible greater seepage losses in the prairie basins. Another difference between the prairie and agricultural strea

Slip stream apparatus and method for treating water in a circulating water system

DOEpatents

Cleveland, Joe R.

1997-01-01

An apparatus (10) for treating water in a circulating water system (12) t has a cooling water basin (14) includes a slip stream conduit (16) in flow communication with the circulating water system (12), a source (36) of acid solution in flow communication with the slip stream conduit (16), and a decarbonator (58) in flow communication with the slip stream conduit (16) and the cooling water basin (14). In use, a slip stream of circulating water is drawn from the circulating water system (12) into the slip stream conduit (16) of the apparatus (10). The slip stream pH is lowered by contact with an acid solution provided from the source (36) thereof. The slip stream is then passed through a decarbonator (58) to form a treated slip stream, and the treated slip stream is returned to the cooling water basin (14).

Noise Source Location and Flow Field Measurements on Supersonic Jets and Implications Regarding Broadband Shock Noise

NASA Technical Reports Server (NTRS)

Podboy, Gary G.; Wernet, Mark P.; Clem, Michelle M.; Fagan, Amy F.

2017-01-01

An experiment was conducted in an effort to obtain data that would provide a better understanding of the origins of broadband shock noise (BBSN). Phased array noise source location and two types of flow field data (background oriented schlieren and particle image velocimetry) were acquired on unheated, single-stream jets. Results are presented for one subsonic and four supersonic operating conditions. These data show that BBSN is created primarily in the downstream portion of the shock train with peak BBSN production occurring near where the average size of the turbulent structures is equal to the shockcell spacing. These data tend to validate theories that BBSN is created by turbulent structures that are as large or larger than the shock spacing.

40 CFR Table 13 to Subpart G of... - Wastewater-Monitoring Requirements for Control Devices

Code of Federal Regulations, 2014 CFR

2014-07-01

.... Carbon adsorber (regenerative) Integrating regeneration stream flow monitoring device having an accuracy of ±10 percent, and Total regeneration stream mass or volumetric flow during carbon bed regeneration cycle(s) For each regeneration cycle, record the total regeneration stream mass or volumetric flow...

40 CFR Table 3 to Subpart Mmm of... - Monitoring Requirements for Control Devices a

Code of Federal Regulations, 2012 CFR

2012-07-01

.... Carbon adsorber (regenerative) Stream flow monitoring device, and 1. Total regeneration stream mass or volumetric flow during carbon bed regeneration cycle(s) 1. For each regeneration cycle, record the total regeneration stream mass or volumetric flow. Carbon bed temperature monitoring device 2. Temperature of carbon...

40 CFR Table 13 to Subpart G of... - Wastewater-Monitoring Requirements for Control Devices

Code of Federal Regulations, 2012 CFR

2012-07-01

.... Carbon adsorber (regenerative) Integrating regeneration stream flow monitoring device having an accuracy of ±10 percent, and Total regeneration stream mass or volumetric flow during carbon bed regeneration cycle(s) For each regeneration cycle, record the total regeneration stream mass or volumetric flow...

40 CFR Table 13 to Subpart G of... - Wastewater-Monitoring Requirements for Control Devices

Code of Federal Regulations, 2013 CFR

2013-07-01

.... Carbon adsorber (regenerative) Integrating regeneration stream flow monitoring device having an accuracy of ±10 percent, and Total regeneration stream mass or volumetric flow during carbon bed regeneration cycle(s) For each regeneration cycle, record the total regeneration stream mass or volumetric flow...

40 CFR Table 3 to Subpart Mmm of... - Monitoring Requirements for Control Devices a

Code of Federal Regulations, 2011 CFR

2011-07-01

.... Carbon adsorber (regenerative) Stream flow monitoring device, and 1. Total regeneration stream mass or volumetric flow during carbon bed regeneration cycle(s) 1. For each regeneration cycle, record the total regeneration stream mass or volumetric flow. Carbon bed temperature monitoring device 2. Temperature of carbon...

40 CFR Table 3 to Subpart Mmm of... - Monitoring Requirements for Control Devices a

Code of Federal Regulations, 2010 CFR

2010-07-01

.... Carbon adsorber (regenerative) Stream flow monitoring device, and 1. Total regeneration stream mass or volumetric flow during carbon bed regeneration cycle(s) 1. For each regeneration cycle, record the total regeneration stream mass or volumetric flow. Carbon bed temperature monitoring device 2. Temperature of carbon...

40 CFR Table 13 to Subpart G of... - Wastewater-Monitoring Requirements for Control Devices

Code of Federal Regulations, 2011 CFR

2011-07-01

.... Carbon adsorber (regenerative) Integrating regeneration stream flow monitoring device having an accuracy of ±10 percent, and Total regeneration stream mass or volumetric flow during carbon bed regeneration cycle(s) For each regeneration cycle, record the total regeneration stream mass or volumetric flow...

40 CFR Table 13 to Subpart G of... - Wastewater-Monitoring Requirements for Control Devices

Code of Federal Regulations, 2010 CFR

2010-07-01

.... Carbon adsorber (regenerative) Integrating regeneration stream flow monitoring device having an accuracy of ±10 percent, and Total regeneration stream mass or volumetric flow during carbon bed regeneration cycle(s) For each regeneration cycle, record the total regeneration stream mass or volumetric flow...

Hydrology of coal-resource areas in the southern Wasatch Plateau, central Utah

USGS Publications Warehouse

Danielson, T.W.; Sylla, D.A.

1982-01-01

The study defines the surface and groundwater hydrology of coal-resources areas in the Southern Wasatch Plateau in Central Utah and, where possible, predicts the hydrologic impacts of underground mining. Discharge data at four streamflow gaging stations indicated that from 5 to 29% of the average annual precipitation on a drainage runs off streams, mainly during the snowmelt period (spring and summer). Most of the base flow of streams originates as spring discharge in the higher altitudes of drainages. Peak flows, average 7-day flood flows, and flood depths were related to basin characteristics in order to develop flood equations for ungaged sites. Chemical quality of surface water was suitable for most uses. Dissolved-solids concentrations ranged from 97 to 835 milligrams per liter in 61 samples collected throughout the area. Data from wells and coal-test holes, and a comprehensive spring inventory indicate that groundwater occurs in all geologic units exposed in the study area. The coal-bearing Blackhawk Formation and underlying Star Point Sandstone are saturated in most areas. Some future mining operations would require dewatering of the Star Point-Blackhawk aquifer. Most of the springs issue from the Flagstaff Limestone and North Horn Formation above the Star Point-Blackhawk aquifer. It is not known whether water in the Flagstaff and North Horn is perched. Dissolved-solids concentrations in groundwater ranged from 105 to 1,080 milligrams per liter in 87 analyzed samples. Water levels in wells, the discharge of springs, benthic invertebrates in streams, and quantity and quality of mine effluents all need to be monitored in order to detect changes in the hydrologic system caused by coal mining. (USGS)

Beaver dams, hydrological thresholds, and controlled floods as a management tool in a desert riverine ecosystem, Bill Williams River, Arizona

USGS Publications Warehouse

Andersen, D.C.; Shafroth, P.B.

2010-01-01

Beaver convert lotic stream habitat to lentic through dam construction, and the process is reversed when a flood or other event causes dam failure. We investigated both processes on a regulated Sonoran Desert stream, using the criterion that average current velocity is < 0.2 m s-1 in a lentic reach. We estimated temporal change in the lotic:lentic stream length ratio by relating beaver pond length (determined by the upstream lentic-lotic boundary position) to dam size, and coupling that to the dam-size frequency distribution and repeated censuses of dams along the 58-km river. The ratio fell from 19:1 when no beaver dams were present to < 3:1 after 7 years of flows favourable for beaver. We investigated the dam failure-flood intensity relationship in three independent trials (experimental floods) featuring peak discharge ranging from 37 to 65 m3 s-1. Major damage (breach ??? 3-m wide) occurred at ??? 20% of monitored dams (n = 7-86) and a similar or higher proportion was moderately damaged. We detected neither a relationship between dam size and damage level nor a flood discharge threshold for initiating major damage. Dam constituent materials appeared to control the probability of major damage at low (attenuated) flood magnitude. We conclude that environmental flows prescribed to sustain desert riparian forest will also reduce beaver-created lentic habitat in a non-linear manner determined by both beaver dam and flood attributes. Consideration of both desirable and undesirable consequences of ecological engineering by beaver is important when optimizing environmental flows to meet ecological and socioeconomic goals. ?? 2010 John Wiley & Sons, Ltd.

Comparison of pesticide concentrations in streams at low flow in six metropolitan areas of the United States

USGS Publications Warehouse

Sprague, Lori A.; Nowell, Lisa H.

2008-01-01

To examine the effect of urban development on pesticide concentrations in streams under low-flow conditions, water samples were collected at stream sites along an urban land use gradient in six environmentally heterogeneous metropolitan areas of the United States. In all six metropolitan areas, total insecticide concentrations generally increased significantly as urban land cover in the basin increased, regardless of whether the background land cover in the basins was agricultural, forested, or shrub land. In contrast, the response of total herbicide concentrations to urbanization varied with the environmental setting. In the three metropolitan areas with predominantly forested background land cover (Raleigh-Durham, NC, USA; Atlanta, GA, USA; Portland, OR, USA), total herbicide concentrations increased significantly with increasing urban land cover. In contrast, total herbicide concentrations were not significantly related to urban land cover in the three remaining metropolitan areas, where total herbicide concentrations appeared to be strongly influenced by agricultural as well as urban sources (Milwaukee-Green Bay, WI, USA; Dallas-Fort Worth, TX, USA), or by factors not measured in the present study, such as water management (Denver, CO, USA). Pesticide concentrations rarely exceeded benchmarks for protection of aquatic life, although these low-flow concentrations are likely to be lower than at other times, such as during peak pesticide-use periods, storm events, or irrigation discharge. Normalization of pesticide concentrations by the pesticide toxicity index - an index of relative potential toxicity - for fish and cladocerans indicated that the pesticides detected at the highest concentrations (herbicides in five of the six metropolitan areas) were not necessarily the pesticides with the greatest potential to adversely affect aquatic life (typically insecticides such as carbaryl, chlorpyrifos, diazinon, and fipronil). ?? 2008 SETAC.

The Western U.S. Drought: How Bad Is It?

NASA Astrophysics Data System (ADS)

Piechota, Thomas; Timilsena, Janek; Tootle, Glenn; Hidalgo, Hugo

2004-08-01

Historical stream flow records and the forecast for 2004 make the current (lpar1999-2004) drought in the southwestern United States the worst one in the past 80 years for portions of the Upper Colorado River Basin (UCRB). For the Colorado River (near Cisco, Utah), the cumulative stream flow deficit (departure from long term mean) for the current drought is almost 11 km3, or approximately 2 years of average stream flow. Although the current drought is the most significant, based on stream flow records, is it the worst ever?

Documentation of the Streamflow-Routing (SFR2) Package to Include Unsaturated Flow Beneath Streams - A Modification to SFR1

USGS Publications Warehouse

Niswonger, Richard G.; Prudic, David E.

2005-01-01

Many streams in the United States, especially those in semiarid regions, have reaches that are hydraulically disconnected from underlying aquifers. Ground-water withdrawals have decreased water levels in valley aquifers beneath streams, increasing the occurrence of disconnected streams and aquifers. The U.S. Geological Survey modular ground-water model (MODFLOW-2000) can be used to model these interactions using the Streamflow-Routing (SFR1) Package. However, the approach does not consider unsaturated flow between streams and aquifers and may not give realistic results in areas with significantly deep unsaturated zones. This documentation describes a method for extending the capabilities of MODFLOW-2000 by incorporating the ability to simulate unsaturated flow beneath streams. A kinematic-wave approximation to Richards' equation was solved by the method of characteristics to simulate unsaturated flow beneath streams in SFR1. This new package, called SFR2, includes all the capabilities of SFR1 and is designed to be used with MODFLOW-2000. Unlike SFR1, seepage loss from the stream may be restricted by the hydraulic conductivity of the unsaturated zone. Unsaturated flow is simulated independently of saturated flow within each model cell corresponding to a stream reach whenever the water table (head in MODFLOW) is below the elevation of the streambed. The relation between unsaturated hydraulic conductivity and water content is defined by the Brooks-Corey function. Unsaturated flow variables specified in SFR2 include saturated and initial water contents; saturated vertical hydraulic conductivity; and the Brooks-Corey exponent. These variables are defined independently for each stream reach. Unsaturated flow in SFR2 was compared to the U.S. Geological Survey's Variably Saturated Two-Dimensional Flow and Transport (VS2DT) Model for two test simulations. For both test simulations, results of the two models were in good agreement with respect to the magnitude and downward progression of a wetting front through an unsaturated column. A third hypothetical simulation is presented that includes interaction between a stream and aquifer separated by an unsaturated zone. This simulation is included to demonstrate the utility of unsaturated flow in SFR2 with MODFLOW-2000. This report includes a description of the data input requirements for simulating unsaturated flow in SFR2.

Flash floods of August 10, 2009, in the Villages of Gowanda and Silver Creek, New York

USGS Publications Warehouse

Szabo, Carolyn O.; Coon, William F.; Niziol, Thomas A.

2011-01-01

Late during the night of August 9, 2009, two storm systems intersected over western New York and produced torrential rain that caused severe flash flooding during the early morning hours of August 10 in parts of Cattaraugus, Chautauqua, and Erie Counties. Nearly 6 inches of rain fell in 1.5 hours as recorded by a National Weather Service weather observer in Perrysburg, which lies between Gowanda and Silver Creek-the communities that suffered the most damage. This storm intensity had an annual exceedance probability of less than 0.2 percent (recurrence interval greater than 500 years). Although flooding along Cattaraugus Creek occurred elsewhere, Cattaraugus Creek was responsible for very little flooding in Gowanda. Rather the small tributaries, Thatcher Brook and Grannis Brook, caused the flooding in Gowanda, as did Silver Creek and Walnut Creek in the Village of Silver Creek. Damages from the flooding were widespread. Numerous road culverts were washed out, and more than one-quarter of the roads in Cattaraugus County were damaged. Many people were evacuated or rescued in Gowanda and Silver Creek, and two deaths occurred during the flood in Gowanda. The water supplies of both communities were compromised by damages to village reservoirs and water-transmission infrastructures. Water and mud damage to residential and commercial properties was extensive. The tri-county area was declared a Federal disaster area and more than $45 million in Federal disaster assistance was distributed to more than 1,500 individuals and an estimated 1,100 public projects. The combined total estimate of damages from the flash floods was greater than $90 million. Over 240 high-water marks were surveyed by the U.S. Geological Survey; a subset of these marks was used to create flood-water-surface profiles for four streams and to delineate the areal extent of flooding in Gowanda and Silver Creek. Flood elevations exceeded previously defined 0.2-percent annual exceedance probability (500-year recurrence interval) elevations by 2 to 4 feet in Gowanda and as much as 6 to 8 feet in Silver Creek. Most of the high-water marks were used in indirect hydraulic computations to estimate peak flows for four streams. The peak flows in Grannis Brook and Thatcher Brook were computed, using the slope-area method, to be 1,400 and 7,600 cubic feet per second, respectively, and peak flow in Silver Creek was computed, using the width-contraction method, to be 19,500 cubic feet per second. The annual exceedance probabilities for flows in these and other basins with small drainage areas that fell almost entirely within the area of heaviest precipitation were less than 0.2 percent (or recurrence intervals greater than 500 years). The peak flow in Cattaraugus Creek at Gowanda was computed, using the slope-area method, to be 33,200 cubic feet per second with an annual exceedance probability of 2.2 percent (recurrence interval of 45 years).

A low cost strategy to monitor the expansion and contraction of the flowing stream network in mountainous headwater catchments

NASA Astrophysics Data System (ADS)

Assendelft, Rick; van Meerveld, Ilja; Seibert, Jan

2017-04-01

Streams are dynamic features in the landscape. The flowing stream network expands and contracts, connects and disconnects in response to rainfall events and seasonal changes in catchment wetness. Sections of the river system that experience these wet and dry cycles are often referred to as temporary streams. Temporary streams are abundant and widely distributed freshwater ecosystems. They account for more than half of the total length of the global stream network, are unique habitats and form important hydrological and ecological links between the uplands and perennial streams. However, temporary streams have been largely unstudied, especially in mountainous headwater catchments. The dynamic character of these systems makes it difficult to monitor them. We describe a low-cost, do-it-yourself strategy to monitor the occurrence of water and flow in temporary streams. We evaluate this strategy in two headwater catchments in Switzerland. The low cost sensor network consists of electrical resistivity sensors, water level switches, temperature sensors and flow sensors. These sensors are connected to Arduino microcontrollers and data loggers, which log the data every 5 minutes. The data from the measurement network are compared with observations (mapping of the temporary stream network) as well as time lapse camera data to evaluate the performance of the sensors. We look at how frequently the output of the sensors (presence and absence of water from the ER and water level data, and flow or no-flow from the flow sensors) corresponds to the observed channel state. This is done for each sensor, per sub-catchment, per precipitation event and per sensor location to determine the best sensor combination to monitor temporary streams in mountainous catchments and in which situation which sensor combination works best. The preliminary results show that the sensors and monitoring network work well. The data from the sensors corresponds with the observations and provides information on the expansion of the stream network pattern.

Hydrologic reconnaissance of western Arctic Alaska, 1976 and 1977

USGS Publications Warehouse

Childers, Joseph M.; Kernodle, Donald R.; Loeffler, Robert M.

1979-01-01

Reconnaissance water-resource investigations were conducted on the western Alaskan Arctic Slope during April 1976 and August 1977; these months are times of winter and summer low flow. The information gathered is important for coordinated development in the area. Such development has been spurred by oil and gas discoveries on the North Slope, most notably at Prudhoe Bay. Little water resources information is currently available. The study area extended from the Colville River to the vicinity of Kotzebue. It included the western Arctic Slope and the western foothills of the Brooks Range. Nine springs, nine lakes and eleven rivers were sampled during the April 1976 reconnaissance trip. Its purpose was to locate winter flow and describe its quantity and quality. Field water-quality measurements made at these sites were: ice thickness, water depth, discharge (spring and streams), specific conductance, water temperature, dissolved oxygen, alkalinity (bicarbonate, HOC3), and pH. A followup summer trip was made in August 1977 to determine flood characteristics of twenty selected streams. Bankfull and maximum evident flood-peak discharges were determined by measuring channel geometry and estimating channel roughness. Aquatic invertebrate samples were collected at springs and flood survey sites visited during both reconnaissance trips. (Woodard-USGS)

Subauroral polarization stream on the outer boundary of the ring current during an energetic ion injection event

NASA Astrophysics Data System (ADS)

Yuan, Zhigang; Qiao, Zheng; Li, Haimeng; Huang, Shiyong; Wang, Dedong; Yu, Xiongdong; Yu, Tao

2017-04-01

Subauroral polarization stream (SAPS) electric field can play an important role in the coupling between the inner magnetosphere and ionosphere; however, the production mechanism of SAPS has not been yet solved. During an energetic ion injection event on 26 March 2004, at latitudes lower than the equatorward boundaries of precipitating plasma sheet electrons and ions, the Defense Meteorological Satellite Program (DMSP) F13 satellite simultaneously observed a strong SAPS with the peak velocity of 1294 m/s and downward flowing field-aligned currents (FACs). Conjugate observations of DMSP F13 and NOAA 15 satellites have shown that FACs flowing into the ionosphere just lie in the outer boundary of the ring current (RC). The downward flowing FACs were observed in a region of positive latitudinal gradients of the ion energy density, implying that the downward flowing FACs are more likely linked to the azimuthal gradient than the radial gradient of the RC ion pressure. Our result demonstrates that RC ion pressure gradients on the outer boundary of the RC in the evening sector during energetic ion injection events can lead to downward flowing FACs so as to cause strong SAPS in condition of low ionospheric conductivities.