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Sample records for 180-day snowmelt streamflows

  1. Snowmelt rate dictates streamflow

    NASA Astrophysics Data System (ADS)

    Barnhart, Theodore B.; Molotch, Noah P.; Livneh, Ben; Harpold, Adrian A.; Knowles, John F.; Schneider, Dominik

    2016-08-01

    Declining mountain snowpack and earlier snowmelt across the western United States has implications for downstream communities. We present a possible mechanism linking snowmelt rate and streamflow generation using a gridded implementation of the Budyko framework. We computed an ensemble of Budyko streamflow anomalies (BSAs) using Variable Infiltration Capacity model-simulated evapotranspiration, potential evapotranspiration, and estimated precipitation at 1/16° resolution from 1950 to 2013. BSA was correlated with simulated baseflow efficiency (r2 = 0.64) and simulated snowmelt rate (r2 = 0.42). The strong correlation between snowmelt rate and baseflow efficiency (r2 = 0.73) links these relationships and supports a possible streamflow generation mechanism wherein greater snowmelt rates increase subsurface flow. Rapid snowmelt may thus bring the soil to field capacity, facilitating below-root zone percolation, streamflow, and a positive BSA. Previous works have shown that future increases in regional air temperature may lead to earlier, slower snowmelt and hence decreased streamflow production via the mechanism proposed by this work.

  2. Snowmelt and streamflow trends in the Rocky Mountains of Colorado

    NASA Astrophysics Data System (ADS)

    Pfohl, A. K. D.; Fassnacht, S. R.

    2016-12-01

    Using the Center of Volume technique has been the most common practice for examining trends in snowmelt contribution to streamflow in snow-dominated watersheds. The dates when 20% and 80% (tQ20 and tQ80, respectively) of the annual flow has passed a gauging station are used as proxies for the start and end of snowmelt contribution. We developed a method to measure streamflow timing using the cumulative hydrograph and applied it to 39 high elevation watersheds across the Southern Rocky Mountains of Colorado for a 40-year study period. We identified other variables related to snowmelt timing to streamflow, including the percent of annual flow and volume at the estimated tstart and tend, as well as the total duration of contribution. After identifying these different values, we used the Mann Kendall Test and Thiel-Sen's Slope to calculate trends in the timing variables. We used the correlation coefficient to explain the variance in the observed trends of the different snowmelt timing variables, using different physiographic characteristics (mean slope, mean elevation, mean winter solar radiation, latitude, and longitude) as well as trends in winter precipitation and summer NDVI. Most of these trends were not statistically significant, but mean slope was best able to explain the variance in trends for tend, Q100, Qend, Qduration, %Qtend, and tQ80 (p < 0.05).

  3. Generation of ensemble streamflow forecasts using an enhanced version of the snowmelt runoff model

    USDA-ARS?s Scientific Manuscript database

    As water demand increases in the western United States, so does the need for accurate streamflow forecasts. We describe a method for generating ensemble streamflow forecasts (1-15 days) using an enhanced version of the snowmelt runoff model (SRM). Forecasts are produced for three snowmelt-dominated ...

  4. Changes in the timing of snowmelt and streamflow in Colorado: A response to recent warming

    USGS Publications Warehouse

    Clow, David W.

    2010-01-01

    Trends in the timing of snowmelt and associated runoff in Colorado were evaluated for the 1978-2007 water years using the regional Kendall test (RKT) on daily snow-water equivalent (SWE) data from snowpack telemetry (SNOTEL) sites and daily streamflow data from headwater streams. The RKT is a robust, nonparametric test that provides an increased power of trend detection by grouping data from multiple sites within a given geographic region. The RKT analyses indicated strong, pervasive trends in snowmelt and streamflow timing, which have shifted toward earlier in the year by a median of 2-3 weeks over the 29-yr study period. In contrast, relatively few statistically significant trends were detected using simple linear regression. RKT analyses also indicated that November-May air temperatures increased by a median of 0.9 degrees C decade-1, while 1 April SWE and maximum SWE declined by a median of 4.1 and 3.6 cm decade-1, respectively. Multiple linear regression models were created, using monthly air temperatures, snowfall, latitude, and elevation as explanatory variables to identify major controlling factors on snowmelt timing. The models accounted for 45% of the variance in snowmelt onset, and 78% of the variance in the snowmelt center of mass (when half the snowpack had melted). Variations in springtime air temperature and SWE explained most of the interannual variability in snowmelt timing. Regression coefficients for air temperature were negative, indicating that warm temperatures promote early melt. Regression coefficients for SWE, latitude, and elevation were positive, indicating that abundant snowfall tends to delay snowmelt, and snowmelt tends to occur later at northern latitudes and high elevations. Results from this study indicate that even the mountains of Colorado, with their high elevations and cold snowpacks, are experiencing substantial shifts in the timing of snowmelt and snowmelt runoff toward earlier in the year.

  5. Using diurnal streamflow and conductivity data to monitor and forecast runoff in a snowmelt dominated watershed

    NASA Astrophysics Data System (ADS)

    Miller, S.; Miller, S. N.

    2016-12-01

    Natural diurnal fluctuations in streamflow are common in many types of streams and scales for different reasons (i.e. snowmelt, evapotranspiration, infiltration, precipitation). Scientific literature has placed little consideration on the role diurnal cycles as they may appear insignificant from a water management point of view; however, recent insights into the timing and shape of the diurnal cycle have led to new methods for eco-hydrologic characterization of a given watershed. The diurnal effect is usually not detectible from visual investigation of a stream, but requires a minimum of hourly continuous measurement. In the 1990s the United States Geological Survey began collecting hourly river stage measurements for thousands of stream gauge stations across the US, ushering in new methods of analysis and comparison. A nested watershed study with ten stream gauging stations recording sub-hourly river stage was deployed in a snowmelt-dominated region of the Medicine Bow National Forest in southeastern Wyoming in 2013. In addition, at each stream gauging station sub-hourly conductivity and temperature data was recorded to aid in eco-hydrologic characterization of the different watersheds. Early summer results show asymmetry in the diurnal cycle during snowmelt, with a steeper rising and a flatter falling limb. As snowmelt becomes a less contributing component of streamflow later in the season, the asymmetry shifts to a flatter rising limb and steeper falling limb. Stream conductivity is low during snowmelt and begins to gradually increase as baseflow becomes a larger portion of total streamflow. The study region is recovering from a mountain pine beetle epidemic that peaked in 2008. 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

  6. Trends in snowmelt-related streamflow timing in the conterminous United States

    NASA Astrophysics Data System (ADS)

    Dudley, R. W.; Hodgkins, G. A.; McHale, M. R.; Kolian, M. J.; Renard, B.

    2017-04-01

    Changes in snowmelt-related streamflow timing have implications for water availability and use as well as ecologically relevant shifts in streamflow. Historical trends in snowmelt-related streamflow timing (winter-spring center volume date, WSCVD) were computed for minimally disturbed river basins in the conterminous United States. WSCVD was computed by summing daily streamflow for a seasonal window then calculating the day that half of the seasonal volume had flowed past the gage. We used basins where at least 30 percent of annual precipitation was received as snow, and streamflow data were restricted to regionally based winter-spring periods to focus the analyses on snowmelt-related streamflow. Trends over time in WSCVD at gages in the eastern U.S. were relatively homogenous in magnitude and direction and statistically significant; median WSCVD was earlier by 8.2 days (1.1 days/decade) and 8.6 days (1.6 days/decade) for 1940-2014 and 1960-2014 periods respectively. Fewer trends in the West were significant though most trends indicated earlier WSCVD over time. Trends at low-to-mid elevation (<1600 m) basins in the West, predominantly located in the Northwest, had median earlier WSCVD by 6.8 days (1940-2014, 0.9 days/decade) and 3.4 days (1960-2014, 0.6 days/decade). Streamflow timing at high-elevation (⩾1600 m) basins in the West had median earlier WSCVD by 4.0 days (1940-2014, 0.5 days/decade) and 5.2 days (1960-2014, 0.9 days/decade). Trends toward earlier WSCVD in the Northwest were not statistically significant, differing from previous studies that observed many large and (or) significant trends in this region. Much of this difference is likely due to the sensitivity of trend tests to the time period being tested, as well as differences in the streamflow timing metrics used among the studies. Mean February-May air temperature was significantly correlated with WSCVD at 100 percent of the study gages (field significant, p < 0.0001), demonstrating the

  7. Modeling streamflow from snowmelt in the upper Rio Grande

    USDA-ARS?s Scientific Manuscript database

    Annual snowpack in the high elevation snowsheds of the Upper Rio Grande (URG) Basin is a vital source of surface water for irrigated agriculture in New Mexico. Maximum streamflow from the annual snowpack usually occurs in early May for the southernmost snowsheds (e.g., Ojo Caliente) and at the end o...

  8. Historical perspective of statewide streamflows during the 2002 and 1977 droughts in Colorado

    USGS Publications Warehouse

    Kuhn, Gerhard

    2005-01-01

    Since 1890, Colorado has experienced a number of widespread drought periods; the most recent statewide drought began during 1999 and includes 2002, a year characterized by precipitation, snowpack accumulation, and streamflows that were much lower than normal. Because the drought of 2002 had a substantial effect on streamflows in Colorado, the U.S. Geological Survey, in cooperation with the Colorado Water Conservation Board, began a study in 2004 to analyze statewide streamflows during 2002 and develop a historical perspective of those streamflows. The purpose of this report is to describe an analysis of streamflows recorded throughout Colorado during the drought of 2002, as well as other drought years such as 1977, and to provide some historical perspective of drought-diminished streamflows in Colorado. Because most streamflows in Colorado are derived from melting of mountain snowpacks during April through July, streamflows primarily were analyzed for the snowmelt (high-flow) period, but streamflows also were analyzed for the winter (low-flow) period. The snowmelt period is defined as April 1 through September 30 and the winter period is defined as October 1 through March 31. Historical daily average streamflows were analyzed on the basis of 7, 30, 90, and 180 consecutive-day periods (N-day) for 154 selected stations in Colorado. Methods used for analysis of the N-day snowmelt and winter streamflows include evaluation of trends in the historical streamflow records, computation of the rank of each annual N-day streamflow value for each station, analysis for years other than 2002 and 1977 with drought-diminished streamflows, and frequency analysis (on the basis of nonexceedance probability) of the 180-day streamflows. Ranking analyses for the N-day snowmelt streamflows indicated that streamflows during 2002 were ranked as the lowest or second lowest historical values at 114-123 stations, or about 74-80 percent of the stations; by comparison, the N-day snowmelt

  9. Predicting streamflows in snowmelt-driven watersheds using the flow duration curve method

    NASA Astrophysics Data System (ADS)

    Kim, D.; Kaluarachchi, J.

    2014-05-01

    Predicting streamflows in snow-fed watersheds in the Western United States is important for water allocation. Since many of these watersheds are heavily regulated through canal networks and reservoirs, predicting expected natural flows and therefore water availability under limited data is always a challenge. This study investigates the applicability of the flow duration curve (FDC) method for predicting natural flows in gauged and regulated snow-fed watersheds. Point snow observations, air temperature, precipitation, and snow water equivalent were used to simulate the snowmelt process with the SNOW-17 model, and extended to streamflow simulation using the FDC method with a modified current precipitation index. For regulated watersheds, a parametric regional FDC method was applied to reconstruct natural flow. For comparison, a simplified tank model was used considering both lumped and semi-distributed approaches. The proximity regionalization method was used to simulate streamflows in the regulated watersheds with the tank model. The results showed that the FDC method is capable of producing satisfactory natural flow estimates in gauged watersheds when high correlation exists between current precipitation index and streamflow. For regulated watersheds, the regional FDC method produced acceptable river diversion estimates, but it seemed to have more uncertainty due to less robustness of the FDC method. In spite of its simplicity, the FDC method is a practical approach with less computational burden for studies with minimal data availability.

  10. Streamflow Estimation from Hydrologic Model Assimilation of Remotely Sensed Snow Information in Snowmelt Dominated Basins

    NASA Astrophysics Data System (ADS)

    Dressler, K. A.; Leavesley, G.; Bales, R.; Fassnacht, S.

    2004-12-01

    The USGS Precipitation Runoff Modeling System (PRMS) hydrological model was used to evaluate the utility of experimental, gridded, 1-km2 snow covered area (SCA) and snow water equivalent (SWE) products in improving the modeling of snowmelt runoff from three headwater basins in the Southwestern United Sates. The SCA product was the fraction of each 1-km2 pixel covered by snow and was derived from NOAA Advanced Very High Resolution Radiometer imagery. The SWE product was developed by combining the SCA product with SWE estimates interpolated from National Resources Conservation Service Snow Telemetry (SNOTEL) point measurements. An eight-year period (1995-2002) was used to compare PRMS simulated streamflow generated with and without the use of the SCA and SWE products. The test basins were the Upper Rio Grande (3,397 km2) in Colorado, and the White (1,634 km2) and Black (1,441 km2) which are tributaries to the Salt River in Arizona. In model runs using the SCA and SWE products, PRMS simulated SCA and SWE values were replaced with the SCA and SWE product values each time step the products were available. The simulated energy and mass balance states of PRMS were also adjusted based on the difference between the current model state and the assimilated estimate. The largest differences between PRMS simulations of SCA and SWE, and those estimated in the SCA and SWE products, occurred in the complex, higher elevation terrain. Simulated streamflow using the assimilated products were as much as 50% less than observed streamflow over the eight year period. The largest differences between observed streamflow and that simulated using the assimilated products occurred in the topographically complex Upper Rio Grande. Differences were smaller in the White and Black basins. Use of an averaging filter to smooth the SCA and SWE products prior to assimilation improved simulated streamflow volume, especially for the Upper Rio Grande basin

  11. Predicting natural streamflows in regulated snowmelt-driven watersheds using regionalization methods

    NASA Astrophysics Data System (ADS)

    Kim, D.; Kaluarachchi, J.

    2013-07-01

    Predicting streamflows in snow-fed watersheds in the Western United States is important for water allocation. Since many of these watersheds are heavily regulated through canal networks and reservoirs, predicting expected natural flows and therefore water availability under limited data is always a challenge. This study investigates the applicability of the flow duration curve (FDC) method for predicting natural flows in gauged and ungauged snow-fed watersheds. Point snow observations, air temperature, precipitation, and snow water equivalent, are used to simulate snowmelt process with SNOW-17 model and extended to streamflow generation by a FDC method with modified current precipitation index. For regulated (ungauged) watersheds, a parametric regional FDC method is applied to reconstruct natural flow. For comparison, a simplified Tank Model is used as well. The proximity regionalization method is used to generate streamflow using the Tank Model in ungauged watersheds. The results show that the FDC method can produce acceptable natural flow estimates in both gauged and ungauged watersheds under data limited conditions. The performance of the FDC method is better in watersheds with relatively low evapotranspiration (ET). Multiple donor data sets including current precipitation index are recommended to reduce uncertainty of the regional FDC method for ungauged watersheds. In spite of its simplicity, the FDC method can perform better than the Tank Model under minimal data availability.

  12. Contribution of Soil Moisture Information to Streamflow Prediction in the Snowmelt Season: A Continental-Scale Analysis

    NASA Technical Reports Server (NTRS)

    Reichle, Rolf; Mahanama, Sarith; Koster, Randal; Lettenmaier, Dennis

    2009-01-01

    In areas dominated by winter snowcover, the prediction of streamflow during the snowmelt season may benefit from three pieces of information: (i) the accurate prediction of weather variability (precipitation, etc.) leading up to and during the snowmelt season, (ii) estimates of the amount of snow present during the winter season, and (iii) estimates of the amount of soil moisture underlying the snowpack during the winter season. The importance of accurate meteorological predictions and wintertime snow estimates is obvious. The contribution of soil moisture to streamflow prediction is more subtle yet potentially very important. If the soil is dry below the snowpack, a significant fraction of the snowmelt may be lost to streamflow and potential reservoir storage, since it may infiltrate the soil instead for later evaporation. Such evaporative losses are presumably smaller if the soil below the snowpack is wet. In this paper, we use a state-of-the-art land surface model to quantify the contribution of wintertime snow and soil moisture information -- both together and separately -- to skill in forecasting springtime streamflow. We find that soil moisture information indeed contributes significantly to streamflow prediction skill.

  13. Onset of snowmelt and streamflow in 2004 in the Western Unites States: How shading may affect spring streamflow timing in a warmer world

    USGS Publications Warehouse

    Lundquist, J.D.; Flint, A.L.

    2006-01-01

    Historic streamflow records show that the onset of snowfed streamflow in the western United States has shifted earlier over the past 50 yr, and March 2004 was one of the earliest onsets on record. Record high temperatures occurred throughout the western United States during the second week of March, and U.S. Geological Survey (USGS) stream gauges throughout the area recorded early onsets of streamflow at this time. However, a set of nested subbasins in Yosemite National Park, California, told a more complicated story. In spite of high air temperatures, many streams draining high-elevation basins did not start flowing until later in the spring. Temperatures during early March 2004 were as high as temperatures in late March 2002, when streams at all of the monitored Yosemite basins began flowing at the same time. However, the March 2004 onset occurred before the spring equinox, when the sun was lower in the sky. Thus, shading and solar radiation differences played a much more important role in 2004, leading to differences in streamflow timing. These results suggest that as temperatures warm and spring melt shifts earlier in the season, topographic effects will play an even more important role than at present in determining snowmelt timing. ?? 2006 American Meteorological Society.

  14. Identifying streamflow sources during spring snowmelt using water chemistry and isotopic composition in semi-arid mountain streams

    NASA Astrophysics Data System (ADS)

    Jin, Li; Siegel, Donald I.; Lautz, Laura K.; Lu, Zunli

    2012-11-01

    SummaryUnderstanding streamflow generation using natural tracers in semi-arid, seasonally snow-covered mountain streams is essential for water resources management, water quality study and evaluation of impacts from climate change. This study reports temporal variations in stable isotopic ratios and concentrations of major dissolved ions of streamwater and precipitation between October, 2005 and May, 2007 in Red Canyon Creek and its tributary, Cherry Creek, draining carbonate-rich catchments on the southeastern flank of Wind River Range (Wyoming, USA). Although the isotopic ratios of oxygen and hydrogen in precipitation increased from approximately -33‰ to -13‰ and -260‰ to -110‰, respectively, during winters of 2006 and 2007, the oxygen and hydrogen isotopic compositions of streamwater at all sites remained unchanged throughout the year at -18.6 ± 0.3‰ (n = 88) and -142 ± 1.6‰ (n = 40) for δ18O and δ2H, respectively. The isotopic values for the streamwater were identical to that found in groundwater, which had the values of -18.6 ± 0.2‰ (n = 26) and -142 ± 1.1‰ (n = 26) for δ18O and δ2H, respectively. On the other hand, the temporal pattern of streamwater chemistry differed in space. In upper Red Canyon Creek, major dissolved ion concentrations in water varied little throughout the year. Nearly constant isotopic and chemical composition of streamwater at upper Red Canyon Creek indicated the dominance of the groundwater contribution throughout the year. In contrast, Cherry Creek had clear dilution of base metal and sulfate concentrations during increasing discharge at snowmelt, which is a clear indication of "new" water coming from fresh snowmelt. The contrasting behavior of stable isotopes and dissolved solutes during snowmelt at Cherry Creek suggests the isotopic tracers traditionally used in hydrograph separation failed to indicate different water sources at Cherry Creek. Combining isotopes and geochemical tracers indicates that

  15. Effect of geomorphic channel restoration on streamflow and groundwater in a snowmelt-dominated watershed

    NASA Astrophysics Data System (ADS)

    Tague, Christina; Valentine, Scott; Kotchen, Matthew

    2008-10-01

    Reengineering of stream channels is a common approach used to restore hydrologic function in degraded landscapes, but there has been little published research analyzing its effectiveness. A key challenge for impact assessment is disentangling the effects of restoration from climate variability. Trout Creek, near Lake Tahoe, California, was reengineered to reestablish hydrologic connectivity between the stream and its former floodplain. Gauges located above and below the site, along with groundwater well measurements, were used to analyze prerestoration and postrestoration hydrology. Results show that restoration has a seasonal impact with statistically significant increases in streamflow during the summer recession period and decreased groundwater table depths across a wide range of streamflow conditions. Paired gauges and statistical models that are robust to serial autocorrelation demonstrate a feasible approach for assessing hydrologic restoration in regions where climate patterns lead to substantial within-year and between-years variation in streamflow.

  16. Hydrologic scales, cloud variability, remote sensing, and models: Implications for forecasting snowmelt and streamflow

    USGS Publications Warehouse

    Simpson, James J.; Dettinger, M.D.; Gehrke, F.; McIntire, T.J.; Hufford, Gary L.

    2004-01-01

    Accurate prediction of available water supply from snowmelt is needed if the myriad of human, environmental, agricultural, and industrial demands for water are to be satisfied, especially given legislatively imposed conditions on its allocation. Robust retrievals of hydrologic basin model variables (e.g., insolation or areal extent of snow cover) provide several advantages over the current operational use of either point measurements or parameterizations to help to meet this requirement. Insolation can be provided at hourly time scales (or better if needed during rapid melt events associated with flooding) and at 1-km spatial resolution. These satellite-based retrievals incorporate the effects of highly variable (both in space and time) and unpredictable cloud cover on estimates of insolation. The insolation estimates are further adjusted for the effects of basin topography using a high-resolution digital elevation model prior to model input. Simulations of two Sierra Nevada rivers in the snowmelt seasons of 1998 and 1999 indicate that even the simplest improvements in modeled insolation can improve snowmelt simulations, with 10%-20% reductions in root-mean-square errors. Direct retrieval of the areal extent of snow cover may mitigate the need to rely entirely on internal calculations of this variable, a reliance that can yield large errors that are difficult to correct until long after the season is complete and that often leads to persistent underestimates or overestimates of the volumes of the water to operational reservoirs. Agencies responsible for accurately predicting available water resources from the melt of snowpack [e.g., both federal (the National Weather Service River Forecast Centers) and state (the California Department of Water Resources)] can benefit by incorporating concepts developed herein into their operational forecasting procedures. ?? 2004 American Meteorological Society.

  17. The pulse of a montane ecosystem: coupled diurnal cycles in solar flux, snowmelt, evapotranspiration, groundwater, and streamflow at Sagehen Creek (Sierra Nevada, California)

    NASA Astrophysics Data System (ADS)

    Kirchner, J. W.

    2016-12-01

    Forested catchments in the subalpine snow zone provide interesting opportunities to study the interplay between energy and water fluxes under seasonally variable degrees of forcing by transpiration and snowmelt. In such catchments, diurnal cycles in solar flux drive snowmelt and evapotranspiration, which in turn lead to diurnal cycles (with opposing phases) in groundwater levels. These in turn are linked to diurnal cycles in stream stage and discharge, which potentially provide a spatially integrated measure of snowmelt and evapotranspiration rates in the surrounding landscape. Here I analyze ecohydrological controls on diurnal stream and groundwater fluctuations induced by snowmelt and evapotranspiration (ET) at Sagehen Creek, in the Sierra Nevada mountains of California. There is a clear 6-hour lag between radiation forcing and the stream or groundwater response. This is not a travel-time delay, but instead a 90-degree dynamical phase lag arising from the integro-differential relationship between groundwater storage and recharge, ET, and streamflow. The time derivative of groundwater levels is strongly positively correlated with solar flux during snowmelt periods, reflecting snowmelt recharge to the riparian aquifer during daytime. Conversely, this derivative is strongly negatively correlated with solar flux during snow-free summer months, reflecting transpiration withdrawals from the riparian aquifer. As the snow cover disappears, the correlation between the solar flux and the time derivative of groundwater levels abruptly shifts from positive (snowmelt dominance) to negative (ET dominance). Stream stage fluctuations integrate these relationships over the altitude range of the catchment. The correlation with solar flux gradually shifts from positive to negative over several weeks, as the snow-covered area contracts higher and higher in the basin. The dates at which the snowmelt and ET signals in the stream cancel each other out occur systematically later at

  18. Prediction of snowmelt derived streamflow in a wetland dominated prairie basin

    NASA Astrophysics Data System (ADS)

    Fang, X.; Pomeroy, J. W.; Westbrook, C. J.; Guo, X.; Minke, A. G.; Brown, T.

    2010-02-01

    The eastern Canadian Prairies are dominated by cropland, pasture, woodland and wetland areas. The region is characterized by many poor and internal drainage systems and large amounts of surface water storage. Consequently, basins here have proven challenging to hydrological model predictions which assume good drainage to stream channels. The Cold Regions Hydrological Modelling platform (CRHM) is an assembly system that can be used to set up physically based, flexible, object oriented models. CRHM was used to create a prairie hydrological model for the externally drained Smith Creek Research Basin (~400 km2), east-central Saskatchewan. Physically based modules were sequentially linked in CRHM to simulate snow processes, frozen soils, variable contributing area and wetland storage and runoff generation. Five "representative basins" (RBs) were used and each was divided into seven hydrological response units (HRUs): fallow, stubble, grassland, river channel, open water, woodland, and wetland as derived from a supervised classification of SPOT 5 imagery. Two types of modelling approaches calibrated and uncalibrated, were set up for 2007/08 and 2008/09 simulation periods. For the calibrated modelling, only the surface depression capacity of upland area was calibrated in the 2007/08 simulation period by comparing simulated and observed hydrographs; while other model parameters and all parameters in the uncalibrated modelling were estimated from field observations of soils and vegetation cover, SPOT 5 imagery, and analysis of drainage network and wetland GIS datasets as well as topographic map based and LiDAR DEMs. All the parameters except for the initial soil properties and antecedent wetland storage were kept the same in the 2008/09 simulation period. The model performance in predicting snowpack, soil moisture and streamflow was evaluated and comparisons were made between the calibrated and uncalibrated modelling for both simulation periods. Calibrated and uncalibrated

  19. The pulse of a montane ecosystem: coupled diurnal cycles in solar flux, snowmelt, evapotranspiration, groundwater, and streamflow at Sagehen Creek (Sierra Nevada, California)

    NASA Astrophysics Data System (ADS)

    Kirchner, James

    2016-04-01

    Forested catchments in the subalpine snow zone provide interesting opportunities to study the interplay between energy and water fluxes under seasonally variable degrees of forcing by transpiration and snowmelt. In such catchments, diurnal cycles in solar flux drive snowmelt and evapotranspiration, which in turn lead to diurnal cycles (with opposing phases) in groundwater levels. These in turn are linked to diurnal cycles in stream stage and discharge, which potentially provide a spatially integrated measure of snowmelt and evapotranspiration rates in the surrounding landscape. Here I analyze ecohydrological controls on diurnal stream and groundwater fluctuations induced by snowmelt and evapotranspiration (ET) at Sagehen Creek, in the Sierra Nevada mountains of California. There is a clear 6-hour lag between radiation forcing and the stream or groundwater response. This is not a travel-time delay, but instead a 90-degree dynamical phase lag arising from the integro-differential relationship between groundwater storage and recharge, ET, and streamflow. The time derivative of groundwater levels is strongly positively correlated with solar flux during snowmelt periods, reflecting snowmelt recharge to the riparian aquifer during daytime. Conversely, this derivative is strongly negatively correlated with solar flux during snow-free summer months, reflecting transpiration withdrawals from the riparian aquifer. As the snow cover disappears, the correlation between the solar flux and the time derivative of groundwater levels abruptly shifts from positive (snowmelt dominance) to negative (ET dominance). During this transition, the groundwater cycles briefly vanish when the opposing forcings (snowmelt and ET) are of equal magnitude, and thus cancel each other out. Stream stage fluctuations integrate these relationships over the altitude range of the catchment. Rates of rise and fall in stream stage are positively correlated with solar flux when the whole catchment is snow

  20. 78 FR 30390 - Applications Delayed More Than 180 Days

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-22

    ... Pipeline and Hazardous Materials Safety Administration Applications Delayed More Than 180 Days AGENCY: Pipeline and Hazardous Materials Safety Administration (PHMSA), DOT. ACTION: List of Applications Delayed... of Hazardous Materials Special Permits and Approvals, Pipeline and Hazardous Materials...

  1. A Distributed Modeling System for Short-Term to Seasonal Ensemble Streamflow Forecasting in Snowmelt Dominated Basins

    SciTech Connect

    Wigmosta, Mark S.; Gill, Muhammad K.; Coleman, Andre M.; Prasad, Rajiv; Vail, Lance W.

    2007-12-01

    This paper describes a distributed modeling system for short-term to seasonal water supply forecasts with the ability to utilize remotely-sensed snow cover products and real-time streamflow measurements. Spatial variability in basin characteristics and meteorology is represented using a raster-based computational grid. Canopy interception, snow accumulation and melt, and simplified soil water movement are simulated in each computational unit. The model is run at a daily time step with surface runoff and subsurface flow aggregated at the basin scale. This approach allows the model to be updated with spatial snow cover and measured streamflow using an Ensemble Kalman-based data assimilation strategy that accounts for uncertainty in weather forecasts, model parameters, and observations used for updating. Model inflow forecasts for the Dworshak Reservoir in northern Idaho are compared to observations and to April-July volumetric forecasts issued by the Natural Resource Conservation Service (NRCS) for Water Years 2000 – 2006. October 1 volumetric forecasts are superior to those issued by the NRCS, while March 1 forecasts are comparable. The ensemble spread brackets the observed April-July volumetric inflows in all years. Short-term (one and three day) forecasts also show excellent agreement with observations.

  2. 12 CFR 313.163 - Notification of debts of 180 days or less.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 12 Banks and Banking 5 2014-01-01 2014-01-01 false Notification of debts of 180 days or less. 313... Notification of debts of 180 days or less. The Director, in his discretion, may also notify the Secretary of the Treasury of debts that have been delinquent for 180 days or less, including debts the FDIC...

  3. 12 CFR 313.163 - Notification of debts of 180 days or less.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 12 Banks and Banking 5 2013-01-01 2013-01-01 false Notification of debts of 180 days or less. 313... Notification of debts of 180 days or less. The Director, in his discretion, may also notify the Secretary of the Treasury of debts that have been delinquent for 180 days or less, including debts the FDIC...

  4. 49 CFR 24.401 - Replacement housing payment for 180-day homeowner-occupants.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 1 2014-10-01 2014-10-01 false Replacement housing payment for 180-day homeowner... Payments § 24.401 Replacement housing payment for 180-day homeowner-occupants. (a) Eligibility. A displaced person is eligible for the replacement housing payment for a 180-day homeowner-occupant if the person:...

  5. 12 CFR 313.163 - Notification of debts of 180 days or less.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 12 Banks and Banking 4 2011-01-01 2011-01-01 false Notification of debts of 180 days or less. 313... Notification of debts of 180 days or less. The Director, in his discretion, may also notify the Secretary of the Treasury of debts that have been delinquent for 180 days or less, including debts the FDIC...

  6. 12 CFR 313.163 - Notification of debts of 180 days or less.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 12 Banks and Banking 5 2012-01-01 2012-01-01 false Notification of debts of 180 days or less. 313... Notification of debts of 180 days or less. The Director, in his discretion, may also notify the Secretary of the Treasury of debts that have been delinquent for 180 days or less, including debts the FDIC...

  7. 12 CFR 313.163 - Notification of debts of 180 days or less.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 12 Banks and Banking 4 2010-01-01 2010-01-01 false Notification of debts of 180 days or less. 313... Notification of debts of 180 days or less. The Director, in his discretion, may also notify the Secretary of the Treasury of debts that have been delinquent for 180 days or less, including debts the FDIC...

  8. Respiratory mechanics after 180 days space mission (EUROMIR'95)

    NASA Astrophysics Data System (ADS)

    Venturoli, Daniele; Semino, Paola; Negrini, Daniela; Miserocchi, Giuseppe

    The present study reports data on respiratory function of lung and chest wall following the 180 days long European — Russian EuroMir '95 space mission. Data reported refer to two subjects studied before the mission, on day 9 and 175 in flight and on days 1, 10, 12, 27 and 120 after return. In-flight vital capacity (VC) and expiratory reserve volume (ERV) were similar to those in supine posture, namely ~ 5% and ~ 30% less than in sitting posture. On day 1 after return, VC was reduced by ~30 % in both postures. This reflected a decrease in ERV (~0.5 L) and in IC (inspiratory capacity, ~ 1.7 L) that could be attributed to a marked weakening of the respiratory muscles. Regain of normal preflight values barely occurred 120 days after return. Post-flight pressure-volume curves of the lung, chest wall and total respiratory system are equal to preflight ones. The pressure-volume curve of the lung in supine posture is displaced to the right relative to sitting posture and shows a lower compliance. As far as the lung in-flight condition resembles that occurring in supine posture, this implies a lower compliance, a greater amount of blood in the pulmonary microvascular bed, a more homogeneous lung perfusion and therefore a greater microvascular filtration rate towards lung interstitium.

  9. Respiratory mechanics after 180 days space mission (EUROMIR'95).

    PubMed

    Venturoli, D; Semino, P; Negrini, D; Miserocchi, G

    1998-01-01

    The present study reports data on respiratory function of lung and chest wall following the 180 days long European - Russian EuroMir '95 space mission. Data reported refer to two subjects studied before the mission, on day 9 and 175 in flight and on days 1, 10, 12, 27 and 120 after return. In-flight vital capacity (VC) and expiratory reserve volume (ERV) were similar to those in supine posture, namely approximately 5% and approximately 30% less than in sitting posture. On day 1 after return, VC was reduced by approximately 30% in both postures. This reflected a decrease in ERV (approximately 0.5 L) and in IC (inspiratory capacity, approximately 1.7 L) that could be attributed to a marked weakening of the respiratory muscles. Regain of normal preflight values barely occurred 120 days after return. Post-flight pressure-volume curves of the lung, chest wall and total respiratory system are equal to preflight ones. The pressure-volume curve of the lung in supine posture is displaced to the right relative to sitting posture and shows a lower compliance. As far as the lung in-flight condition resembles that occurring in supine posture, this implies a lower compliance, a greater amount of blood in the pulmonary microvascular bed, a more homogeneous lung perfusion and therefore a greater microvascular filtration rate towards lung interstitium.

  10. Slower snowmelt in a warmer world

    NASA Astrophysics Data System (ADS)

    Musselman, Keith N.; Clark, Martyn P.; Liu, Changhai; Ikeda, Kyoko; Rasmussen, Roy

    2017-02-01

    There is general consensus that projected warming will cause earlier snowmelt, but how snowmelt rates will respond to climate change is poorly known. We present snowpack observations from western North America illustrating that shallower snowpack melts earlier, and at lower rates, than deeper, later-lying snow-cover. The observations provide the context for a hypothesis of slower snowmelt in a warmer world. We test this hypothesis using climate model simulations for both a control time period and re-run with a future climate scenario, and find that the fraction of meltwater volume produced at high snowmelt rates is greatly reduced in a warmer climate. The reduction is caused by a contraction of the snowmelt season to a time of lower available energy, reducing by as much as 64% the snow-covered area exposed to energy sufficient to drive high snowmelt rates. These results have unresolved implications on soil moisture deficits, vegetation stress, and streamflow declines.

  11. The Sub-Daily Distribution of Snowmelt

    NASA Astrophysics Data System (ADS)

    Webb, R.; Gooseff, M. N.; Fassnacht, S. R.

    2015-12-01

    The hydrologic cycle in many mountainous headwaters around the world have snowmelt dominated hydrographs. In addition to water resources for communities and ecosystems, high rates of snowmelt can cause flooding that results in damages to infrastructure. The standard in the United States flood forecasting looks primarily at rainfall estimates but lacks estimates for high rates of snowmelt in regions such as the Southern Rocky Mountains. Recent studies have shown that events such as a 10 year 24 hour snowmelt event is as much as 45% greater than the same recurrence interval rain event. Additionally, this 24 hour snowmelt likely occurs over a much shorter time period due to snowmelt being primarily driven by solar radiation. This study presents and tests a sub-daily temporal distribution of snowmelt. The snowmelt distribution presented herein is tested against hourly data for known daily melt rates from snow telemetry (SNOTEL) stations, and then for conditions when weekly or bi-weekly snow loss is known. It is additionally utilized for modeling a one-dimensional soil profile for infiltration across the soil-snow interface. The intent of this study is to create a less computationally intensive method than the mass energy approach and improve upon the simple degree-day method for the representation of snowmelt at sub-daily time steps. This can be used for streamflow, groundwater recharge, soil moisture distribution, and other land surface modeling efforts. Results of the study display strong agreement with hourly SNOTEL data from Colorado Front Range stations for an assumed 8-hour melt period. Peak flow estimates from snowmelt driven floods could be estimated from long-term datasets to calculate frequency of these flood events. Further application of this sub-daily distribution of snowmelt could be for partially or fully glaciated watersheds with modifications for differences in latitude and/or elevation causing longer or shorter periods of melt per day.

  12. Slower snowmelt in a warmer world

    NASA Astrophysics Data System (ADS)

    Musselman, K. N.; Clark, M. P.; Liu, C.; Ikeda, K.; Rasmussen, R.

    2016-12-01

    There is general consensus that projected warming will cause earlier snowmelt, but how snowmelt rates will respond to climate change is poorly known. We present snowpack observations from western North America that show that shallower snowpack melts earlier and at lower rates than deeper, later-lying snow-cover. The observations provide the context for a hypothesis that reduced snowpack in a warmer world will melt at lower rates. We test this hypothesis using high-resolution Weather Research and Forecasting model simulations over much of North America for a historical decade (2000-2010), verified against snowpack and precipitation observations, and then re-run with a pseudo-global-warming technique. Results show that high snowmelt rates are greatly reduced in a warmer climate. The reduction is caused by substantial late-season snow-cover depletion at a time of high seasonal energy availability. Regions of largest reductions in high melt rates include the Sierra Nevada, Pacific Northwest, and lower elevations of northern Idaho, Montana and the Canadian Pacific Ranges. Increases in snowmelt rates were small, exhibited greater regional and elevational variability, and generally impacted low historical melt rates in winter and early-spring. The large reduction of high spring snowmelt rates in a warmer world has unresolved and important implications on future streamflow as catchment wetness thresholds may be exceeded less frequently, contributing to soil moisture deficits, vegetation stress and streamflow declines.

  13. 76 FR 19902 - Energy Conservation Program for Consumer Products: Decision and Order Granting 180-Day Extension...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-11

    ... 180-Day Extension of Compliance Date for Residential Furnaces and Boilers Test Procedure Amendments... amendments to the DOE test procedure for residential furnaces and boilers related to the standby mode and off... residential furnaces and boilers starting on October 15, 2011. FOR FURTHER INFORMATION CONTACT: Dr. Michael...

  14. 49 CFR 24.401 - Replacement housing payment for 180-day homeowner-occupants.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... displacement dwelling or the term of the new mortgage, whichever is shorter. (3) The interest rate on the new...) Has actually owned and occupied the displacement dwelling for not less than 180 days immediately prior... displacement dwelling or, in the case of condemnation, the date the full amount of the estimate of...

  15. 49 CFR 24.401 - Replacement housing payment for 180-day homeowner-occupants.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... displacement dwelling or the term of the new mortgage, whichever is shorter. (3) The interest rate on the new...) Has actually owned and occupied the displacement dwelling for not less than 180 days immediately prior... displacement dwelling or, in the case of condemnation, the date the full amount of the estimate of...

  16. 49 CFR 24.401 - Replacement housing payment for 180-day homeowner-occupants.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... displacement dwelling or the term of the new mortgage, whichever is shorter. (3) The interest rate on the new...) Has actually owned and occupied the displacement dwelling for not less than 180 days immediately prior... displacement dwelling or, in the case of condemnation, the date the full amount of the estimate of...

  17. Rapid streamflow generation from subsurface flow

    USDA-ARS?s Scientific Manuscript database

    Traditional streamflow forecasting from snowmelt-dominated basins has been based on snowpack dynamics. A weakness of this approach is a failure to accommodate the increasingly common mid-winter rainfall events, which are often responsible for major flooding. We recently combined a snowmelt and soil ...

  18. Studies of effects of closed microbial ecology. Report of 180-day test period

    NASA Technical Reports Server (NTRS)

    Kenyon, A. J.

    1972-01-01

    Experiments were performed to determine the influence closed microbial ecologies have on modification or simplification of natural intestinal flora of ferrets in a closed environmental system. On the basis of previous tests in which certain species (Salmonella and Bacteroides) were decreased at 90 days of enclosure, a second trial was constructed for 180-day tests. In this trial there was little difference in the 8 major classes of intestinal flora between animals in the Open and Closed environmental groups except for the level of Lactobacillus. It is of extreme importance to note that when both Open and Closed groups contracted hemorrhagic gastritis, the interrelationship of this agent with other intestinal flora produced a more profound effect on animals from the Closed Group, particularly with reference to Lactobacillus levels.

  19. Slower snowmelt in a warmer world

    NASA Astrophysics Data System (ADS)

    Musselman, Keith; Clark, Martyn; Liu, Changhai; Ikeda, Kyoko; Rasmussen, Roy

    2017-04-01

    There is general consensus that projected warming will cause earlier snowmelt, but how the melt rates of seasonal snow-cover will respond to climate change is poorly known. We present snowpack observations from western North America that show that shallower snowpack melts earlier and at lower rates than deeper, later-lying snow-cover. The observations provide the context for a hypothesis that reduced snowpack in a warmer world will melt at lower rates. We test this hypothesis using high-resolution Weather Research and Forecasting model simulations over much of North America for a historical decade (2000-2010), verified against snowpack and precipitation observations, and then re-run with a pseudo-global-warming technique. We find that the fraction of meltwater volume produced at high snowmelt rates is greatly reduced in a warmer climate. The reduction is caused by a contraction of the snowmelt season to a time of lower available energy, reducing by as much as 64% the snow-covered area exposed to energy sufficient to drive high snowmelt rates. The results have important implications on soil moisture deficits, vegetation stress and streamflow declines over large areas of the world.

  20. Relations between winter climatic variables and April streamflows in New England and implications for summer streamflows

    USGS Publications Warehouse

    Hodgkins, Glenn A.; Dudley, Robert W.; Schalk, Luther F.

    2012-01-01

    A period of much below normal streamflow in southern New England during April 2012 raised concerns that a long-term period of drought could evolve through late spring and summer, leading to potential water availability issues. To understand better the relations between winter climatic variables and April streamflows, April streamflows from 31 streamflow gages in New England that drain relatively natural watersheds were tested for year-to-year correlation with winter precipitation and air temperature from nearby meteorological sites. Higher winter (December through March) precipitation is associated with higher April streamflows at many gages in northern and central New England. This implies that snowpack accumulation is an important mechanism for winter water storage and subsequently important for spring streamflows in this area. Higher March air temperatures are associated with lower April streamflows at many gages in central and southern New England, likely because the majority of snowmelt runoff occurs before April in warm years. A warm March 2012 contributed to early snowmelt runoff in New England and to much below normal April streamflows in southern New England. However, no strong relation was found between historical April streamflows and late-spring or summer streamflows in New England. The lack of a strong relation implies that summer precipitation, rather than spring conditions, controls summer streamflows.

  1. A hydrogeologic framework for characterizing summer streamflow sensitivity to climate warming in the Pacific Northwest, USA

    Treesearch

    M. Safeeq; G.E. Grant; S.L. Lewis; M.G. Kramer; B. Staab

    2014-01-01

    Summer streamflows in the Pacific Northwest are largely derived from melting snow and groundwater discharge. As the climate warms, diminishing snowpack and earlier snowmelt will cause reductions in summer streamflow. Most regional-scale assessments of climate change impacts on streamflow use downscaled temperature and precipitation projections from general circulation...

  2. Modelling urban snowmelt runoff

    NASA Astrophysics Data System (ADS)

    Valeo, C.; Ho, C. L. I.

    2004-12-01

    Few investigations have been made into modelling snowmelt in urban areas; hence, current urban snowmelt routines have adopted parameters and approaches intended for rural areas that are not appropriate in an urban environment. This paper examines problems with current urban snowmelt models and proposes a model that uses parameters developed from field studies focusing exclusively on urban snow. The Urban Snow Model (USM) uses an energy balance scheme at an hourly time step, changes in urban snow albedo, and incorporates eight different types of redistributed snow cover. USM is tested against observed flow data from a small residential community located in Calgary, Alberta. The degree-day method for snowmelt, the SWMM model, and a modified version of USM that incorporates a partial energy budget scheme relying only on net radiation, are also tested against the observed flow data. The full energy budget version of USM outperformed all other models in terms of time to peak, peak flowrate and model efficiency; however, the modified version of USM fared quite well and is recommended when a lack of data exists. The degree-day method and the SWMM models fared poorly and were unable to simulate peak flowrates in most cases. The tests also demonstrated the need to distribute snow into appropriate snow covers in order to simulate peak flowrates accurately and provide good model efficiency.

  3. Hydrologic modelling of the effect of snowmelt and temperature on a mountainous watershed

    NASA Astrophysics Data System (ADS)

    Kang, Kwangmin; Lee, Joo Hyoung

    2014-06-01

    Snowmelt-runoff modelling in a mountainous basin is perceived as difficult due to the complexity of simulation. Theoretically, the snowmelt process should be influenced by temperature changes. It is still controversial as how to incorporate the temperature changes into the snowmelt-runoff model in a mountainous basin. This paper presents the results of a study in the North Fork American River basin where the snowmelt-runoff mechanism is modelled by relating the temperature changes to the elevation band in the basin. In this study, a distributed hydrologic model is used to explore the orographic effects on the snowmelt-runoff using the snowfall-snowmelt routine in Soil and Water Assessment Tool (SWAT). Three parameters, namely maximum snowmelt factor, minimum snowmelt factor, and snowpack temperature lag were analysed during the simulation. The model was validated using streamflow data from October 1, 1991 to September 30, 1994 with and without considering the elevation band. The result of this study suggests that the snowmelt-runoff model associated with the elevation band better represents the snowmelt-runoff mechanism in terms of Nash-Sutcliffe coefficient ( E NS ), R 2, and Root Mean Square Error (RMSE).

  4. Application of a stochastic snowmelt model for probabilistic decisionmaking

    NASA Technical Reports Server (NTRS)

    Mccuen, R. H.

    1983-01-01

    A stochastic form of the snowmelt runoff model that can be used for probabilistic decision-making was developed. The use of probabilistic streamflow predictions instead of single valued deterministic predictions leads to greater accuracy in decisions. While the accuracy of the output function is important in decisionmaking, it is also important to understand the relative importance of the coefficients. Therefore, a sensitivity analysis was made for each of the coefficients.

  5. Effects of warming on groundwater flow in mountainous snowmelt-dominated catchments

    NASA Astrophysics Data System (ADS)

    Evans, S. G.; Ge, S.; Molotch, N. P.

    2015-12-01

    In mountainous regions, warmer air temperatures have led to an earlier onset of spring snowmelt and lower snowmelt rates; i.e. because snowmelt has shifted earlier when energy availability is lower. These changes to snowmelt will likely affect the partitioning of snowmelt water between surface runoff and groundwater flow, and therefore, the lag time between snowmelt and streamflow. While the connection between snowmelt and surface runoff has been well-studied, the impact of snowmelt variability on groundwater flow processes has received limited attention, especially in mountainous catchments. We construct a two-dimensional, finite element, coupled flow and heat transport hydrogeologic model to evaluate how changes in snowmelt onset and rate may alter groundwater discharge to streams in mountainous catchments. The coupled hydrogeologic model simulates seasonally frozen ground by incorporating permeability variation as a function of temperature and allows for modeling of pore water freeze and thaw. We apply the model to the Green Lakes Valley (GLV) watershed in the Rocky Mountains of Colorado, a representative snowmelt-dominated catchment. Snowmelt for the GLV catchment is reconstructed from a 12 year (1996-2007) dataset of hydrometeorological records and satellite-derived snow covered area. Modeling results suggest that on a yearly cycle, groundwater infiltration and discharge is limited by the seasonally frozen subsurface. Under average conditions from 1996 to 2007, maximum groundwater discharge to the surface lags maximum snowmelt by approximately two months. Ongoing modeling is exploring how increasing air temperatures affect lag times between snowmelt and groundwater discharge to streams. This study has implications for water resource availability and its temporal variability in a warming global climate.

  6. Trends and sensitivities of low streamflow extremes to discharge timing and magnitude in pacific northwest mountain streams

    USDA-ARS?s Scientific Manuscript database

    Historical streamflow data from the Pacific Northwest indicate that the precipitation amount has been the dominant control on the magnitude of low streamflow extremes compared to the air temperature-affected timing of snowmelt runoff. The relative sensitivities of low streamflow to precipitation and...

  7. Trends and sensitivities of low streamflow extremes to discharge timing and magnitude in Pacific Northwest mountain streams

    Treesearch

    Patrick R. Kormos; Charlie Luce; Seth J. Wenger; Wouter R. Berghuijs

    2016-01-01

    Path analyses of historical streamflow data from the Pacific Northwest indicate that the precipitation amount has been the dominant control on the magnitude of low streamflow extremes compared to the air temperature-affected timing of snowmelt runoff. The relative sensitivities of low streamflow to precipitation and temperature changes have important...

  8. Regional patterns of postwildfire streamflow response in the Western United States: The importance of scale-specific connectivity

    Treesearch

    Dennis W. Hallema; Ge Sun; Kevin D. Bladon; Steven P. Norman; Peter V. Caldwell; Yongqiang Liu; Steven G. McNulty

    2017-01-01

    Wildfires can impact streamflow by modifying net precipitation, infiltration, evapotranspiration, snowmelt, and hillslope run‐off pathways. Regional differences in fire trends and postwildfire streamflow responses across the conterminous United States have spurred concerns about the impact on streamflow in forests that serve as water resource areas. This is notably the...

  9. The importance of snowmelt spatiotemporal variability for isotope-based hydrograph separation in a high-elevation catchment

    NASA Astrophysics Data System (ADS)

    Schmieder, Jan; Hanzer, Florian; Marke, Thomas; Garvelmann, Jakob; Warscher, Michael; Kunstmann, Harald; Strasser, Ulrich

    2016-12-01

    Seasonal snow cover is an important temporary water storage in high-elevation regions. Especially in remote areas, the available data are often insufficient to accurately quantify snowmelt contributions to streamflow. The limited knowledge about the spatiotemporal variability of the snowmelt isotopic composition, as well as pronounced spatial variation in snowmelt rates, leads to high uncertainties in applying the isotope-based hydrograph separation method. The stable isotopic signatures of snowmelt water samples collected during two spring 2014 snowmelt events at a north- and a south-facing slope were volume weighted with snowmelt rates derived from a distributed physics-based snow model in order to transfer the measured plot-scale isotopic composition of snowmelt to the catchment scale. The observed δ18O values and modeled snowmelt rates showed distinct inter- and intra-event variations, as well as marked differences between north- and south-facing slopes. Accounting for these differences, two-component isotopic hydrograph separation revealed snowmelt contributions to streamflow of 35 ± 3 and 75 ± 14 % for the early and peak melt season, respectively. These values differed from those determined by formerly used weighting methods (e.g., using observed plot-scale melt rates) or considering either the north- or south-facing slope by up to 5 and 15 %, respectively.

  10. Assessment of the timing of daily peak streamflow during melt season in a snow dominated watershed

    USDA-ARS?s Scientific Manuscript database

    Previous studies have shown that gauge-observed daily streamflow peak times (DPT) during spring snowmelt can exhibit distinct temporal shifts through the season. These shifts have been attributed to three processes that affect the timing of snowmelt arrival: 1) melt flux translation through the snow...

  11. A subchronic (180-day) oral toxicity study of ethyl tertiary-butyl ether, a bioethanol, in rats.

    PubMed

    Miyata, Katsumi; Koga, Takayuki; Aso, Sunao; Hoshuyama, Satsuki; Ajimi, Syozo; Furukawa, Kotaro

    2014-07-01

    A subchronic (180-day) toxicity study was conducted to evaluate the effects of ethyl tertiary-butyl ether (ETBE), a biomass fuel, in male and female rats. ETBE was administered at dose levels of 0, 5, 25, 100 and 400 mg/kg/body weight (b.w.)/day by gavage. No treatment-related adverse effects were observed at 5, 25 or 100 mg/kg. Centrilobular hypertrophy of hepatocytes was observed in males and females and their relative liver weights were increased, suggesting enhanced metabolic activity. From these results, we concluded that the no observed adverse effect level of ETBE was 100 mg/kg b.w./day under the conditions tested.

  12. Deep groundwater mediates streamflow response to climate warming in the Oregon Cascades

    Treesearch

    Christina Tague; Gordon Grant; Mike Farrell; Janet Choate; Anne Jefferson

    2008-01-01

    Recent studies predict that projected climate change will lead to significant reductions in summer streamflow in the mountainous regions of the Western United States. Hydrologic modeling directed at quantifying these potential changes has focused on the magnitude and timing of spring snowmelt as the key control on the spatial temporal pattern of summer streamflow. We...

  13. August streamflow

    NASA Astrophysics Data System (ADS)

    Streamflows varied across the country during August, with record low flows reported in New York and on the Columbia River at the Dalles, Oreg., while record high flows were reported in Alabama, Kansas, and North Dakota, according to the end of the month check on water resources conditions by the U.S. Geological Survey (USGS). USGS hydrologists said that a nationwide tally of the 171 streamflow gaging stations that reported during August showed that 25% (43 stations) recorded flows in the above-normal range, 59% (101 stations) had flows in the normal range, and 16% (27 stations) recorded flows in the below-normal range.

  14. Dust-on-snow and the Timing of Peak Streamflow in the Upper Rio Grande

    NASA Astrophysics Data System (ADS)

    Steele, C. M.; Elias, E.; Moffitt, A.; Beltran, I.; Rango, A.

    2015-12-01

    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 of temperature-index snow runoff models (such as the Snowmelt Runoff Model [SRM]) for predicting streamflow. In previous work, we have used SRM to simulate historical streamflow from 26 Upper Rio Grande sub-basins. Because dust radiative forcing can alter the relation between temperature and snowmelt, we wanted to find out if there is evidence of dust radiative forcing and earlier snowmelt in our study basins, particularly for those years where SRM was less successful in simulating streamflow. To accomplish this we have used openly-available data such as EPA air quality station measurements of particulate matter up to 10 micrometers (PM10); streamflow data from the USGS National Water Information System and Colorado Division of Water Resources; temperature, precipitation and snow water equivalent (SWE) from NRCS SNOTEL stations and remotely sensed data products from the MODIS sensor. Initial analyses indicate that a connection between seasonal dust concentration and streamflow timing (date of onset of warm-season snowmelt, date of streamflow center-of-volume) can be detected. This is further supported by time series analysis of MODIS-derived estimates of snow albedo and dust radiative-forcing in alpine and open subalpine snow fields.

  15. 1996-2007 Interannual Spatio-Temporal Variability in Snowmelt in Two Montane Watersheds

    NASA Astrophysics Data System (ADS)

    Jepsen, S. M.; Molotch, N. P.; Williams, M. W.; Rittger, K. E.; Sickman, J. O.

    2010-12-01

    Snowmelt is a primary water resource for urban/agricultural centers and ecosystems near mountain regions. Stream chemistry from montane catchments is controlled by the flowpaths of water from snowmelt and the timing and duration of snow coverage. A process level understanding of the variability in these processes requires an understanding of the effect of changing climate and anthropogenic loading on spatio-temporal snowmelt patterns. With this as our objective, we applied a snow reconstruction model (SRM) to two well-studied montane watersheds, Tokopah Basin (TOK), California and Green Lake 4 Valley (GLV), Colorado, to examine interannual variability in the timing and location of snowmelt in response to variable climate conditions during the period from 1996 to 2007. The reconstruction model back solves for snowmelt by combining surface energy fluxes, inferred from meteorological data, with sequences of melt season snow images derived from satellite data (i.e., snowmelt depletion curves). The SRM explained 84% of the observed interannual variability in maximum watershed SWE in TOK, with errors ranging from -23 to +27% for the different years. For GLV4, the SRM explained 61% of the interannual variability, with errors ranging from -37 to +34%. In GLV4, interannual variability in snowmelt timing is a factor of four greater than the variability in streamflow timing, unlike in TOK where the ratio is nearly 1:1. We attribute this difference primarily to differences in the magnitude of the turbulent fluxes and the hydrogeology of the two study areas.

  16. Hydrogeologic controls on streamflow sensitivity to climate variation

    Treesearch

    Anne Jefferson; Anne Nolin; Sarah Lewis; Christina Tague

    2008-01-01

    Climate models project warmer temperatures for the north-west USA, which will result in reduced snowpacks and decreased summer streamflow. This paper examines how groundwater, snowmelt, and regional climate patterns control discharge at multiple time scales, using historical records from two watersheds with contrasting geological properties and drainage efficiencies....

  17. Changes toward earlier streamflow timing across western North America

    USGS Publications Warehouse

    Stewart, I.T.; Cayan, D.R.; Dettinger, M.D.

    2005-01-01

    The highly variable timing of streamflow in snowmelt-dominated basins across western North America is an important consequence, and indicator, of climate fluctuations. Changes in the timing of snowmelt-derived streamflow from 1948 to 2002 were investigated in a network of 302 western North America gauges by examining the center of mass for flow, spring pulse onset dates, and seasonal fractional flows through trend and principal component analyses. Statistical analysis of the streamflow timing measures with Pacific climate indicators identified local and key large-scale processes that govern the regionally coherent parts of the changes and their relative importance. Widespread and regionally coherent trends toward earlier onsets of springtime snowmelt and streamflow have taken place across most of western North America, affecting an area that is much larger than previously recognized. These timing changes have resulted in increasing fractions of annual flow occurring earlier in the water year by 1-4 weeks. The immediate (or proximal) forcings for the spatially coherent parts of the year-to-year fluctuations and longer-term trends of streamflow timing have been higher winter and spring temperatures. Although these temperature changes are partly controlled by the decadal-scale Pacific climate mode [Pacific decadal oscillation (PDO)], a separate and significant part of the variance is associated with a springtime warming trend that spans the PDO phases. ?? 2005 American Meteorological Society.

  18. BOREAS HYD-9 Streamflow Data

    NASA Technical Reports Server (NTRS)

    Hall, Forrest G. (Editor); Knapp, David E. (Editor); Kouwen, Nick; Soulis, Ric; Jenkinson, Wayne; Graham, Allyson; Neff, Todd; Smith, David E. (Technical Monitor)

    2000-01-01

    The Boreal Ecosystem-Atmosphere Study (BOREAS) Hydrology (HYD)-9 team collected several data sets containing precipitation and streamflow measurements over the BOREAS study areas. These streamflow data were collected by the HYD-09 science team to support its research into meltwater supply to the soil during the spring melt period. These data were also collected for HYD-09's research into the evolution of soil moisture, evaporation, and runoff from the end of the snowmelt period through freeze up. Data were collected in the BOREAS Southern Study Area (SSA) and Northern Study Area (NSA) from April until October in 1994, 1995, and 1996. Gauges southwest-1 and northwest-1 were operated year-round; however, data may not be available for both gauges for all three years. The data are available in tabular ASCII files. The HYD-09 streamflow data are available from the Earth Observing System Data and Information System (EOSDIS) Oak Ridge National Laboratory (ORNL) Distributed Active Archive Center (DAAC). The data files are available on a CD-ROM (see document number 20010000884).

  19. December streamflow

    NASA Astrophysics Data System (ADS)

    Streamflow was in the normal range or above that range in most of the United States and southern Canada during December. Below-normal flows persisted in parts of Nova Scotia, the Atlantic coast states, Saskatchewan, British Columbia, and Hawaii. Flows decreased into the below-normal range in parts of southwestern Canada, Washington, Oregon, California, Wyoming, Nebraska, Virginia, North and South Carolina, and Georgia.

  20. Extended healing validation of an artificial tendon to connect the quadriceps muscle to the Tibia: 180-day study.

    PubMed

    Melvin, Alan J; Litsky, Alan S; Mayerson, Joel L; Stringer, Keith; Juncosa-Melvin, Natalia

    2012-07-01

    Whenever a tendon or its bone insertion is disrupted or removed, existing surgical techniques provide a temporary connection or scaffolding to promote healing, but the interface of living to non-living materials soon breaks down under the stress of these applications, if it must bear the load more than acutely. Patients are thus disabled whose prostheses, defect size, or mere anatomy limit the availability or outcomes of such treatments. Our group developed the OrthoCoupler™ device to join skeletal muscle to prosthetic or natural structures without this interface breakdown. In this study, the goat knee extensor mechanism (quadriceps tendon, patella, and patellar tendon) was removed from the right hind limb in 16 goats. The device connected the quadriceps muscle to a stainless steel bone plate on the tibia. Mechanical testing and histology specimens were collected from each operated leg and contralateral unoperated control legs at 180 days. Maximum forces in the operated leg (vs. unoperated) were 1,400 ± 93 N (vs. 1,179 ± 61 N), linear stiffnesses were 33 ± 3 N/mm (vs. 37 ± 4 N/mm), and elongations at failure were 92.1 ± 5.3 mm (vs. 68.4 ± 3.8 mm; mean ± SEM). Higher maximum forces (p = 0.02) and elongations at failure (p=0.008) of legs with the device versus unoperated controls were significant; linear stiffnesses were not (p=0.3). We believe this technology will yield improved procedures for clinical challenges in orthopedic oncology, revision arthroplasty, tendon transfer, and tendon injury reconstruction.

  1. Extended Healing Validation of an Artificial Tendon to Connect the Quadriceps Muscle to the Tibia: 180-day Study

    PubMed Central

    Melvin, Alan J.; Litsky, Alan S.; Mayerson, Joel L.; Stringer, Keith; Juncosa-Melvin, Natalia

    2011-01-01

    Whenever a tendon or its bone insertion is disrupted or removed, existing surgical techniques provide a temporary connection or scaffolding to promote healing, but the interface of living to nonliving materials soon breaks down under the stress of these applications, if it must bear the load more than acutely. Patients are thus disabled whose prostheses, defect size, or mere anatomy limit the availability or outcomes of such treatments. Our group developed the OrthoCoupler™ device to join skeletal muscle to prosthetic or natural structures without this interface breakdown. In this study, the goat knee extensor mechanism (quadriceps tendon, patella, and patellar tendon) was removed from the right hind limb in 16 goats. The device connected the quadriceps muscle to a stainless steel bone plate on the tibia. Mechanical testing and histology specimens were collected from each operated leg and contra lateral unoperated control legs at 180 days. Maximum forces in the operated leg (vs. unoperated) were 1400± 93N (vs. 1179± 61 N), linear stiffnesses were 33± 3 N/mm (vs. 37 ± 4N/mm), and elongations at failure were 92.1 ± 5.3 mm (vs. 68.4 ± 3.8 mm; mean ± SEM). Higher maximum forces (p = 0.02) and elongations at failure (p = 0.008) of legs with the device versus unoperated controls were significant; linear stiffnesses were not (p = 0.3). We believe this technology will yield improved procedures for clinical challenges in orthopaedic oncology, revision arthroplasty, tendon transfer, and tendon injury reconstruction. PMID:22179930

  2. Aromatic hydrocarbons in a controlled ecological life support system during a 4-person-180-day integrated experiment.

    PubMed

    Dai, Kun; Yu, Qingni; Zhang, Zhou; Wang, Yuan; Wang, Xinming

    2018-01-01

    Indoor air quality is vital to the health and comfort of people who live inside a controlled ecological life support system (CELSS) built for long-term space explorations. Here we measured aromatic hydrocarbons to assess their sources and health risks during a 4-person-180-day integrated experiment inside a CELSS with four cabins for growing crops, vegetables and fruits and other two cabins for working, accommodations and resources management. During the experiment, the average concentrations of benzene, ethylbenzene, m,p-xylenes and o-xylene were found to decrease exponentially from 7.91±3.72, 37.2±35.2, 100.8±111.7 and 46.8±44.1μg/m(3) to 0.39±0.34, 1.4±0.5, 2.8±0.7 and 2.1±0.9μg/m(3), with half-lives of 25.3, 44.8, 44.7 and 69.3days, respectively. Toluene to benzene ratios indicated emission from construction materials or furniture to be a dominant source for toluene, and concentrations of toluene fluctuated during the experiment largely due to the changing sorption by growing plants. The cancer and no-cancer risks based on exposure pattern of the crews were insignificant in the end of the experiment. This study also suggested that using low-emitting materials/furniture, growing plants and purifying air actively would all help to lower hazardous air pollutants inside CELSS. Broadly, the results would benefit not only the development of safe and comfort life support systems for space exploration but also the understanding of interactions between human and the total environment in closed systems. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Snowmelt Runoff Model in Japan

    NASA Technical Reports Server (NTRS)

    Ishihara, K.; Nishimura, Y.; Takeda, K.

    1985-01-01

    The preliminary Japanese snowmelt runoff model was modified so that all the input variables arc of the antecedent days and the inflow of the previous day is taken into account. A few LANDSAT images obtained in the past were effectively used to verify and modify the depletion curve induced from the snow water equivalent distribution at maximum stage and the accumulated degree days at one representative point selected in the basin. Together with the depletion curve, the relationship between the basin ide daily snowmelt amount and the air temperature at the point above are exhibited homograph form for the convenience of the model user. The runoff forecasting procedure is summarized.

  4. What Drives Changes in the Timing of Snowmelt Runoff in the Western United States?

    NASA Astrophysics Data System (ADS)

    Stewart, I. T.; Cayan, D. R.; Dettinger, M. D.

    2001-12-01

    Future climate-change scenarios forecast widespread reductions in snowpack accumulation and resulting declines in snowmelt-derived streamflow in many mountainous watersheds around the world. These predicted changes could have important consequences for water resources supply and management by changing flood regimes and the seasonal availability of water resources in ways that current structures and policies may not be able to accommodate. The western United States, where precipitation and runoff are strongly seasonal, represent a very important laboratory for studying the impact of climatic changes on streamflow timing and water resources, as well as offering opportunities for identifying the immediate causes of such changes. It is a matter of considerable concern, then, that regionally coherent trends towards an earlier start of the snowmelt runoff season has been identified in the near-natural flow series of rivers throughout the western United States. The advance in the timing of the spring snowmelt pulse is associated with decreased April-July (AMJJ) fractional flows, and increasing fractions of the annual runoff occurring earlier in the water year, especially in March. Most of these trends began in the late 1940s and have continued through the 1990's. They are present in snowmelt-dominated streams throughout the western United States, except for an area in the southern Rocky Mountains/southwest. In order to clarify the patterns of year-to-year as well as trending changes in streamflow timing principal component analyses (PCAs) were carried out on three measures: (a) the day of onset of the spring snowmelt runoff pulses in each river, (b) the AMJJ fractional flows, and (c) the March fractional flows. The PCAs identify broad regions of common variability in the changes of streamflow timing by all three measures. The two regions that most consistently vary together in terms of the magnitude of trends and the redistribution of streamflow are the Sierra Nevada

  5. Recent tree die-off has little effect on streamflow in contrast to expected increases from historical studies

    USDA-ARS?s Scientific Manuscript database

    Recent bark beetle epidemics have caused regional-scale tree mortality in many snowmelt-dominated headwater catchments of western North America. Initial expectations of increased streamflow have not been supported by observations, and the basin-scale response of annual streamflow is largely unknown....

  6. Simulated impact of climate change on hydrology of multiple watersheds using traditional and recommended snowmelt runoff model methodology

    USDA-ARS?s Scientific Manuscript database

    For more than three decades, researchers have utilized the Snowmelt Runoff Model (SRM) to test the impacts of climate change on streamflow of snow-fed systems. In this study, the hydrological effects of climate change are modeled over three sequential years using SRM with both typical and recommende...

  7. 49 CFR 24.502 - Replacement housing payment for 180-day mobile homeowner displaced from a mobile home, and/or...

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 1 2012-10-01 2012-10-01 false Replacement housing payment for 180-day mobile homeowner displaced from a mobile home, and/or from the acquired mobile home site. 24.502 Section 24.502... ACQUISITION FOR FEDERAL AND FEDERALLY-ASSISTED PROGRAMS Mobile Homes § 24.502 Replacement housing payment...

  8. 49 CFR 24.502 - Replacement housing payment for 180-day mobile homeowner displaced from a mobile home, and/or...

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 1 2011-10-01 2011-10-01 false Replacement housing payment for 180-day mobile homeowner displaced from a mobile home, and/or from the acquired mobile home site. 24.502 Section 24.502... ACQUISITION FOR FEDERAL AND FEDERALLY-ASSISTED PROGRAMS Mobile Homes § 24.502 Replacement housing payment...

  9. 49 CFR 24.502 - Replacement housing payment for 180-day mobile homeowner displaced from a mobile home, and/or...

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 1 2013-10-01 2013-10-01 false Replacement housing payment for 180-day mobile homeowner displaced from a mobile home, and/or from the acquired mobile home site. 24.502 Section 24.502... ACQUISITION FOR FEDERAL AND FEDERALLY-ASSISTED PROGRAMS Mobile Homes § 24.502 Replacement housing payment...

  10. 49 CFR 24.502 - Replacement housing payment for 180-day mobile homeowner displaced from a mobile home, and/or...

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 1 2014-10-01 2014-10-01 false Replacement housing payment for 180-day mobile homeowner displaced from a mobile home, and/or from the acquired mobile home site. 24.502 Section 24.502... ACQUISITION FOR FEDERAL AND FEDERALLY-ASSISTED PROGRAMS Mobile Homes § 24.502 Replacement housing payment...

  11. 49 CFR 24.502 - Replacement housing payment for 180-day mobile homeowner displaced from a mobile home, and/or...

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 1 2010-10-01 2010-10-01 false Replacement housing payment for 180-day mobile homeowner displaced from a mobile home, and/or from the acquired mobile home site. 24.502 Section 24.502... ACQUISITION FOR FEDERAL AND FEDERALLY-ASSISTED PROGRAMS Mobile Homes § 24.502 Replacement housing payment...

  12. Relationship Between Satellite-Derived Snow Cover and Snowmelt-Runoff Timing in the Wind River Range, Wyoming

    NASA Technical Reports Server (NTRS)

    Hall, Dorothy K.; Foster, James L.; DiGirolamo, Nicolo E.; Riggs, George A.

    2010-01-01

    MODIS-derived snow cover measured on 30 April in any given year explains approximately 89 % of the variance in stream discharge for maximum monthly streamflow in that year. Observed changes in streamflow appear to be related to increasing maximum air temperatures over the last four decades causing lower spring snow-cover extent. The majority (>70%) of the water supply in the western United States comes from snowmelt, thus analysis of the declining spring snowpack (and resulting declining stream discharge) has important implications for streamflow management in the drought-prone western U.S.

  13. Hydrological response of an Alpine catchment to rainfall and snowmelt events

    NASA Astrophysics Data System (ADS)

    Penna, D.; van Meerveld, H. J.; Zuecco, G.; Dalla Fontana, G.; Borga, M.

    2016-06-01

    Alpine catchments are important sources of fresh water but compared to lower altitude catchments our understanding of the hydrological functioning of these catchments during rainfall and snowmelt events is still limited. The objectives of this study were i) to identify the dominant runoff generation mechanisms in the 0.14-km2 Bridge Creek Catchment in the Italian Dolomites during nine rainfall-runoff events and six snowmelt-runoff events in spring, summer and autumn of 2010-2012; and ii) to assess the effect of the selection of the pre-event water sample on the isotope hydrograph separation results. The isotopic composition of the pre-event water was determined by either a stream water sample taken prior to the event or the average of 19 stream water samples taken during baseflow conditions. The hydrograph separation results for the two methods were very similar for the rainfall events but differed for the snowmelt events. Average event water contributions ranged between 4% and 19% or 2% and 20% of the total runoff during rainfall events, and between 7% and 25% or 9% and 38% during snowmelt events, depending on the method used to determine the isotopic composition of pre-event water. Event water contributions were important during large rainfall events, intense rainfall events and late in the snowmelt season, with maximum event water contributions up to 37% and 46%, depending on the method used for determining the pre-event water composition. The electrical conductivity of stream water tended to first decrease and reach a minimum before peak streamflow and then to increase above pre-event values. The results of this study suggest that during dry conditions, direct channel precipitation and overland flow from the permanently saturated part of the riparian zone dominated the runoff response, with limited contributions of riparian or hillslope groundwater. During wet or very wet conditions (large rainfall events or peak snowmelt), saturation overland flow increased

  14. Organic contaminant amplification during snowmelt.

    PubMed

    Meyer, Torsten; Wania, Frank

    2008-04-01

    The release of organic contaminants from melting snow poses risks to aquatic and terrestrial organisms and to humans who rely on drinking water and food production from regions that are seasonally snow-covered. Measured and model-predicted spring peak concentrations in waters receiving snowmelt motivate a thorough investigation of organic contaminant behaviour during melting. On the basis of the current understanding of snow metamorphosis, snowmelt hydrology and chemical partitioning in snow, this critical review aims to provide a qualitative picture of the processes involved in the release of organic contaminants from a melting snowpack. The elution sequence of organic substances during snowmelt is strongly dependent on their environmental partitioning properties and the physical properties of the snowpack. Water-soluble organic contaminants can be discharged in greatly elevated concentrations at an early stage of melting, while the bulk of the hydrophobic chemicals attached to particles is often released at the end of the melt period. Melting of a highly metamorphosed and deep snowpack promotes such shock load releases, whereas a shallow snow cover over a relatively warm ground experiencing irregular melting over the winter season is unlikely to generate notable peak releases of organic substances. Meltwater runoff over frozen ground directly transfers contaminant shock loads into receiving water bodies, while permeable soils buffer and dilute the contaminants. A more quantitative understanding of the behaviour of organic contaminants in varying snowmelt scenarios will depend on controlled laboratory studies combined with field investigations. Reliable numerical process descriptions will need to be developed to integrate water quality and contaminant fate models.

  15. Hydrometeorological model for streamflow prediction

    USGS Publications Warehouse

    Tangborn, Wendell V.

    1979-01-01

    The hydrometeorological model described in this manual was developed to predict seasonal streamflow from water in storage in a basin using streamflow and precipitation data. The model, as described, applies specifically to the Skokomish, Nisqually, and Cowlitz Rivers, in Washington State, and more generally to streams in other regions that derive seasonal runoff from melting snow. Thus the techniques demonstrated for these three drainage basins can be used as a guide for applying this method to other streams. Input to the computer program consists of daily averages of gaged runoff of these streams, and daily values of precipitation collected at Longmire, Kid Valley, and Cushman Dam. Predictions are based on estimates of the absolute storage of water, predominately as snow: storage is approximately equal to basin precipitation less observed runoff. A pre-forecast test season is used to revise the storage estimate and improve the prediction accuracy. To obtain maximum prediction accuracy for operational applications with this model , a systematic evaluation of several hydrologic and meteorologic variables is first necessary. Six input options to the computer program that control prediction accuracy are developed and demonstrated. Predictions of streamflow can be made at any time and for any length of season, although accuracy is usually poor for early-season predictions (before December 1) or for short seasons (less than 15 days). The coefficient of prediction (CP), the chief measure of accuracy used in this manual, approaches zero during the late autumn and early winter seasons and reaches a maximum of about 0.85 during the spring snowmelt season. (Kosco-USGS)

  16. Mercury on the move during snowmelt in Vermont

    USGS Publications Warehouse

    Shanley, James B.; Schuster, P.F.; Reddy, M.M.; Roth, D.A.; Taylor, H.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.

  17. Mercury on the move during snowmelt in Vermont

    NASA Astrophysics Data System (ADS)

    Shanley, James B.; Schuster, Paul F.; Reddy, Michael M.; Roth, David A.; Taylor, Howard E.; Aiken, George R.

    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.

  18. Modeling streamflow response from Minnesota peatlands

    SciTech Connect

    Guertin, D.P.

    1984-01-01

    To aid in the development of Minnesota's 7 million acres of peatlands, and to evaluate the hydrologic impacts and reclamation options associated with such development, a Peatland Hydrologic Impact Model (PHIM) was devised. PHIM is a deterministic, continuous simulation model designed to simulate streamflow resulting from rainfall and snowmelt under both natural and altered (mined) conditions. It is largely physically based and requires watershed information and hydrometeorological data that are usually available in an operational setting. PHIM can provide both daily and hourly estimates of streamflow, PHIM consists of 5 submodels, 3 land type submodels for natural peatlands, mined peatlands and mineral soil uplands and 2 routing submodels for channel reaches and reservoirs. Streamflow from headwater peatland watersheds can be simulated by combining the submodels in the order that best describes the basin. The model was tested on the basis of stormflow events form a 3758 ha undisturbed peatland and a 155 ha peatland that had undergone ditching and peat mining for horticultural purposes. Simulated streamflow volumes averaged 86 and 91% of observed volumes for the undisturbed and mined area, respectively. Peat discharges were simulated within 84 and 65% of observed values, respectively.

  19. Snow Cover, Snowmelt Timing and Stream Power in the Wind River Range, Wyoming

    NASA Technical Reports Server (NTRS)

    Hall, Dorothy K.; Foster, James L.; DiGirolamo, Nicolo E.; Riggs, George A.

    2011-01-01

    Earlier onset of springtime weather, including earlier snowmelt, has been documented in the western United States over at least the last 50 years. Because the majority (is greater than 70%) of the water supply in the western U.S. comes from snowmelt, analysis of the declining spring snowpack (and shrinking glaciers) has important implications for the management of streamflow. The amount of water in a snowpack influences stream discharge which can also influence erosion and sediment transport by changing stream power, or the rate at which a stream can do work, such as move sediment and erode the stream bed. The focus of this work is the Wind River Range (WRR) in west-central Wyoming. Ten years of Moderate-Resolution Imaging Spectroradiometer (MODIS) snow-cover, cloud-gap-filled (CGF) map products and 30 years of discharge and meteorological station data are studied. Streamflow data from streams in WRR drainage basins show lower annual discharge and earlier snowmelt in the decade of the 2000s than in the previous three decades, though no trend of either lower streamflow or earlier snowmelt was observed within the decade of the 2000s. Results show a statistically-significant trend at the 95% confidence level (or higher) of increasing weekly maximum air temperature (for three out of the five meteorological stations studied) in the decade of the 1970s, and also for the 40-year study period as a whole. The extent of snow-cover (percent of basin covered) derived from the lowest elevation zone (2500-3000 m) of the WRR, using MODIS CGF snow-cover maps, is strongly correlated with maximum monthly discharge on 30 April, where Spearman's Rank correlation, rs,=0.89 for the decade of the 2000s. We also investigated stream power for Bull Lake Creek above Bull Lake; and found a trend (significant at the 90% confidence level) toward reduced stream power from 1970 to 2009. Observed changes in streamflow and stream power may be related to increasing weekly maximum air temperature

  20. Changes in snowmelt runoff timing in western North America under a 'business as usual' climate change scenario

    USGS Publications Warehouse

    Stewart, I.T.; Cayan, D.R.; Dettinger, M.D.

    2004-01-01

    Spring snowmelt is the most important contribution of many rivers in western North America. If climate changes, this contribution may change. A shift in the timing of springtime snowmelt towards earlier in the year already is observed during 1948-2000 in many western rivers. Streamflow timing changes for the 1995-2099 period are projected using regression relations between observed streamflow-timing responses in each river, measured by the temporal centroid of streamflow (CT) each year, and local temperature (TI) and precipitation (PI) indices. Under 21st century warming trends predicted by the Parallel Climate Model (PCM) under business-as-usual greenhouse-gas emissions, streamflow timing trends across much of western North America suggest even earlier springtime snowmelt than observed to date. Projected CT changes are consistent with observed rates and directions of change during the past five decades, and are strongest in the Pacific Northwest, Sierra Nevada, and Rocky Mountains, where many rivers eventually run 30-40 days earlier. The modest PI changes projected by PCM yield minimal CT changes. The responses of CT to the simultaneous effects of projected TI and PI trends are dominated by the TI changes. Regression-based CT projections agree with those from physically-based simulations of rivers in the Pacific Northwest and Sierra Nevada.

  1. 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.

  2. Streamflow data: Chapter 13

    USGS Publications Warehouse

    Wiche, Gregg J.; Holmes, Robert

    2016-01-01

    Streamflow data are vital for a variety of water-resources issues, from flood warning to water supply planning. The collection of streamflow data is usually an involved and complicated process. This chapter serves as an overview of the streamflow data collection process. Readers with the need for the detailed information on the streamflow data collection process are referred to the many references noted in this chapter.

  3. Streamflow, Infiltration, and Recharge in Arroyo Hondo, New Mexico

    USGS Publications Warehouse

    Moore, Stephanie J.

    2007-01-01

    Infiltration events in channels that flow only sporadically produce focused recharge to the Tesuque aquifer in the Espa?ola Basin. The current study examined the quantity and timing of streamflow and associated infiltration in Arroyo Hondo, an unregulated mountain-front stream that enters the basin from the western slope of the Sangre de Cristo Mountains. Traditional methods of stream gaging were combined with environmental-tracer based methods to provide the estimates. The study was conducted during a three-year period, October 1999?October 2002. The period was characterized by generally low precipitation and runoff. Summer monsoonal rains produced four brief periods of streamflow in water year 2000, only three of which extended beyond the mountain front, and negligible runoff in subsequent years. The largest peak flow during summer monsoon events was 0.59 cubic meters per second. Snowmelt was the main contributor to annual streamflow. Snowmelt produced more cumulative flow downstream from the mountain front during the study period than summer monsoonal rains. The presence or absence of streamflow downstream of the mountain front was determined by interpretation of streambed thermographs. Infiltration rates were estimated by numerical modeling of transient vertical streambed temperature profiles. Snowmelt extended throughout the instrumented reach during the spring of 2001. Flow was recorded at a station two kilometers downstream from the mountain front for six consecutive days in March. Inverse modeling of this event indicated an average infiltration rate of 1.4 meters per day at this location. For the entire study reach, the estimated total annual volume of infiltration ranged from 17,100 to 246,000 m3 during water years 2000 and 2001. During water year 2002, due to severe drought, streamflow and streambed infiltration in the study reach were both zero.

  4. Accounting for Vegetation Effects in Spatially Distributed Snowmelt Modeling

    NASA Astrophysics Data System (ADS)

    Garen, D. C.; Marks, D.

    2004-05-01

    The effects of vegetation on snowpack energy dynamics can be highly significant and must be taken into account when simulating snowmelt. This becomes challenging, however, for spatially distributed models covering large areas such as river basins. In this case, processes occurring at the scale of individual trees or bushes must be parameterized and upscaled to the size of the model's grid cells, which could range from 10 up to a few hundred meters. An application of a spatially distributed energy balance snowmelt model to the Boise River basin in Idaho, USA has required the development of algorithms to account for the effects of vegetation (especially forest) on the climate input data to the model. This particularly affects the solar and thermal radiation input to the snowpack, including not only the direct effects of the vegetation but also the effect of vegetation debris on the snow albedo. Vegetation effects on vertical profiles of wind speed and temperature could not be considered due to limited measurements, and only a crude estimate of wind speed differences between forested and nonforested grid cells was used. The simulated snow fields were verified using point snow water equivalent and snow depth data as well as satellite images of snow covered area. Although good results were obtained in these comparisons, each of these methods has limitations, in that point measurements are not necessarily representative of a grid cell, and satellite images have a coarse resolution and cannot detect snow under trees. Another test was to use the simulated snowmelt fields as input to a spatially distributed water balance and streamflow simulation model, which indicated that the volume and timing of snowmelt input to the basin were accurately represented. A limitation of the modeling method used is that the models are run independently in sequence, the output of one being stored and becoming the input of the next. This means that there is no opportunity for feedbacks between

  5. Oxidative stress induced by lead, cadmium and arsenic mixtures: 30-day, 90-day, and 180-day drinking water studies in rats: an overview.

    PubMed

    Fowler, Bruce A; Whittaker, Margaret H; Lipsky, Mike; Wang, Gensheng; Chen, Xue-Qing

    2004-10-01

    Humans are frequently exposed to combinations of lead (Pb), cadmium (Cd) and Arsenic (As) but there is a paucity of actual data on the molecular effects of these agents at low dose levels. The present factorial design studies were undertaken in rats to examine the effects of these agents at LOEL dose levels on a number of molecular parameters of oxidative stress in hematopoietic and renal organ systems following oral exposure in drinking water at 30, 90 and 180 day time points. Results of these studies demonstrated dynamic, time-dependent alterations in both molecular targets and inducible oxidative stress protective systems in target cell populations. In general, cellular protective systems, which protected against oxidative damage at the 90 day time point, appeared to be finite such that molecular manifestations of oxidative stress became statistically significant at the 180 day time point for several of the combination exposure groups. These data demonstrate the importance of duration of exposure in assessing the toxic potential of Pb, Cd and As mixtures at low dose levels.

  6. Exposure to Pb, Cd, and As mixtures potentiates the production of oxidative stress precursors: 30-day, 90-day, and 180-day drinking water studies in rats

    SciTech Connect

    Whittaker, Margaret H.; Wang, Gensheng; Chen Xueqing; Lipsky, Michael; Smith, Donald; Gwiazda, Roberto; Fowler, Bruce A.

    2011-07-15

    Exposure to chemical mixtures is a common and important determinant of toxicity and is of particular concern due to their appearance in sources of drinking water. Despite this, few in vivo mixture studies have been conducted to date to understand the health impact of chemical mixtures compared to single chemicals. Interactive effects of lead (Pb), cadmium (Cd) and arsenic (As) were evaluated in 30-, 90-, and 180-day factorial design drinking water studies in rats designed to test the hypothesis that ingestion of such mixtures at individual component Lowest-Observed-Effect-Levels (LOELs) results in increased levels of the pro-oxidant delta aminolevulinic acid (ALA), iron, and copper. LOEL levels of Pb, Cd, and As mixtures resulted in the increased presence of mediators of oxidative stress such as ALA, copper, and iron. ALA increases were followed by statistically significant increases in kidney copper in the 90- and 180-day studies. Statistical evidence of interaction was identified for six biologically relevant variables: blood delta aminolevulinic acid dehydratase (ALAD), kidney ALAD, urinary ALA, urinary iron, kidney iron, and kidney copper. The current investigations underscore the importance of considering interactive effects that common toxic agents such as Pb, Cd, and As may have upon one another at low-dose levels. The interactions between known toxic trace elements at biologically relevant concentrations shown here demonstrate a clear need to rigorously review methods by which national/international agencies assess health risks of chemicals, since exposures may commonly occur as complex mixtures.

  7. Sensitivity of soil water availability to changing snowmelt timing in the western U.S.

    NASA Astrophysics Data System (ADS)

    Harpold, Adrian A.; Molotch, Noah P.

    2015-10-01

    The ecohydrological effects of changing snowmelt are strongly mediated by soil moisture. We utilize 259 Snow Telemetry stations across the western U.S. to address two questions: (1) how do relationships between peak soil moisture (PSM) timing and the day of snow disappearance (DSD) vary across ecoregions and (2) what is the regional sensitivity of PSM timing to earlier DSD associated with warming and drying scenarios? All western U.S. ecoregions showed significant relationships between the timing of PSM and DSD. Changes in the timing of PSM based on warming predicted for the middle and end of the 21st century ranged from 1 to 9 days and from 6 to 17 days among ecoregions, respectively. The maritime ecoregions PSM timing were 2-3 times more sensitive to warming and drying versus the interior mountain ecoregions. This work suggests that soil hydrology modifies the effects of earlier snowmelt on regional streamflow response and vegetation water stress.

  8. Spatial patterns of March and September streamflow trends in Pacific Northwest Streams, 1958-2008

    USGS Publications Warehouse

    Chang, Heejun; Jung, Il-Won; Steele, Madeline; Gannett, Marshall

    2012-01-01

    . Consequently, a better understanding of the relationships among summer streamflow, precipitation, snowmelt, elevation, and geology can help water managers predict the response of regional summer streamflow to global warming.

  9. Interannual variability of snowmelt in the Sierra Nevada and Rocky Mountains, United States: examples from two alpine watersheds

    USGS Publications Warehouse

    Jepsen, Steven M.; Molotch, Noah P.; Williams, Mark W.; Rittger, Karl E.; Sickman, James O.

    2012-01-01

    The distribution of snow and the energy flux components of snowmelt are intrinsic characteristics of the alpine water cycle controlling the location of source waters and the effect of climate on streamflow. Interannual variability of these characteristics is relevant to the effect of climate change on alpine hydrology. Our objective is to characterize the interannual variability in the spatial distribution of snow and energy fluxes of snowmelt in watersheds of a maritime setting, Tokopah Basin (TOK) in California's southern Sierra Nevada, and a continental setting, Green Lake 4 Valley (GLV4) in Colorado's Front Range, using a 12 year database (1996–2007) of hydrometeorological observations and satellite-derived snow cover. Snowpacks observed in GLV4 exhibit substantially greater spatial variability than in TOK (0.75 versus 0.28 spatial coefficient of variation). In addition, modeling results indicate that the net turbulent energy flux contribution to snowmelt in GLV4 is, on average, 3 times greater in magnitude (mean 29% versus 10%) and interannual variability (standard deviation 17% versus 6%) than in TOK. These energy flux values exhibit strong seasonality, increasing as the melt season progresses to times later in the year (R2 = 0.54–0.77). This seasonality of energy flux appears to be associated with snowmelt rates that generally increase with onset date of melt (0.02 cm d-2). This seasonality in snowmelt rate, coupled to differences in hydrogeology, may account for the observed differences in correspondence between the timing of snowmelt and timing of streamflow in these watersheds.

  10. Interannual variability of snowmelt in the Sierra Nevada and Rocky Mountains, United States: Examples from two alpine watersheds

    NASA Astrophysics Data System (ADS)

    Jepsen, Steven M.; Molotch, Noah P.; Williams, Mark W.; Rittger, Karl E.; Sickman, James O.

    2012-02-01

    The distribution of snow and the energy flux components of snowmelt are intrinsic characteristics of the alpine water cycle controlling the location of source waters and the effect of climate on streamflow. Interannual variability of these characteristics is relevant to the effect of climate change on alpine hydrology. Our objective is to characterize the interannual variability in the spatial distribution of snow and energy fluxes of snowmelt in watersheds of a maritime setting, Tokopah Basin (TOK) in California's southern Sierra Nevada, and a continental setting, Green Lake 4 Valley (GLV4) in Colorado's Front Range, using a 12 year database (1996-2007) of hydrometeorological observations and satellite-derived snow cover. Snowpacks observed in GLV4 exhibit substantially greater spatial variability than in TOK (0.75 versus 0.28 spatial coefficient of variation). In addition, modeling results indicate that the net turbulent energy flux contribution to snowmelt in GLV4 is, on average, 3 times greater in magnitude (mean 29% versus 10%) and interannual variability (standard deviation 17% versus 6%) than in TOK. These energy flux values exhibit strong seasonality, increasing as the melt season progresses to times later in the year (R2 = 0.54-0.77). This seasonality of energy flux appears to be associated with snowmelt rates that generally increase with onset date of melt (0.02 cm d-2). This seasonality in snowmelt rate, coupled to differences in hydrogeology, may account for the observed differences in correspondence between the timing of snowmelt and timing of streamflow in these watersheds.

  11. Exposure to Pb, Cd, and As mixtures potentiates the production of oxidative stress precursors: 30-day, 90-day, and 180-day drinking water studies in rats.

    PubMed

    Whittaker, Margaret H; Wang, Gensheng; Chen, Xue-Qing; Lipsky, Michael; Smith, Donald; Gwiazda, Roberto; Fowler, Bruce A

    2011-07-15

    Exposure to chemical mixtures is a common and important determinant of toxicity and is of particular concern due to their appearance in sources of drinking water. Despite this, few in vivo mixture studies have been conducted to date to understand the health impact of chemical mixtures compared to single chemicals. Interactive effects of lead (Pb), cadmium (Cd) and arsenic (As) were evaluated in 30-, 90-, and 180-day factorial design drinking water studies in rats designed to test the hypothesis that ingestion of such mixtures at individual component Lowest-Observed-Effect-Levels (LOELs) results in increased levels of the pro-oxidant delta aminolevulinic acid (ALA), iron, and copper. LOEL levels of Pb, Cd, and As mixtures resulted in the increased presence of mediators of oxidative stress such as ALA, copper, and iron. ALA increases were followed by statistically significant increases in kidney copper in the 90- and 180-day studies. Statistical evidence of interaction was identified for six biologically relevant variables: blood delta aminolevulinic acid dehydratase (ALAD), kidney ALAD, urinary ALA, urinary iron, kidney iron, and kidney copper. The current investigations underscore the importance of considering interactive effects that common toxic agents such as Pb, Cd, and As may have upon one another at low-dose levels. The interactions between known toxic trace elements at biologically relevant concentrations shown here demonstrate a clear need to rigorously review methods by which national/international agencies assess health risks of chemicals, since exposures may commonly occur as complex mixtures. Copyright © 2011. Published by Elsevier Inc.

  12. From Snow to Flow: Predicting the Timing of Peak Streamflow Using SNOTEL Ablation Curves

    NASA Astrophysics Data System (ADS)

    Ferguson, K. J.; McNamara, J. P.; Abramovich, R.

    2014-12-01

    It is well understood that there exists a relationship between mountainous snowpack and seasonal streamflow. For snow-dominated river basins within the western United States, ~ 80% of streamflow is a result of seasonal snowmelt. In Idaho, where a significant amount of winter precipitation is stored as snowpack, predictions for the timing and magnitude of peak streamflow are essential for many water users, including water resource and irrigation managers. Of particular interest is the relationship between the timing of snowmelt and the timing of peak streamflow. While agencies such as the Natural Resources Conservation Service (NRCS) are tasked with the responsibility of providing water supply forecasts, few methods have used a data-driven, empirical modeling approach to investigate relationships between ablation timing monitored by the NRCS SNOTEL program and streamflow monitored by the United States Geological Survey (USGS). Such analyses could provide predictive tools that allow water users and managers to easily access and interpret information about peak streamflow. Idaho hosts over 80 SNOTEL sites that report hydrometeorological data, and 213 streamflow gauging stations. The goal of this study is to establish relationships between the timing of ablation at SNOTEL stations and peak streamflow within select basins in Idaho, and to synthesize results into user-friendly visualization tools that will provide estimates of the probability that peak streamflow will occur within a certain number of days as ablation progresses from 0 to 100%. In our initial test basin, the Boise River basin, we evaluated melt-out levels in increments of 10% from three SNOTEL sites located in the basin and produced cumulative density function (CDF) curves to illustrate the probability of peak streamflow occurring within a given number of days from the date at which the SNOTEL site reached each melt-out level.

  13. Improvement of Operational Streamflow Prediction with MODIS-derived Fractional Snow Covered Area Observations

    NASA Astrophysics Data System (ADS)

    Bender, S.; Burgess, A.; Goodale, C. E.; Mattmann, C. A.; Miller, W. P.; Painter, T. H.; Rittger, K. E.; Stokes, M.; Werner, K.

    2013-12-01

    Water managers in the western United States depend heavily on the timing and magnitude of snowmelt-driven runoff for municipal supply, irrigation, maintenance of environmental flows, and power generation. The Colorado Basin River Forecast Center (CBRFC) of the National Weather Service issues operational forecasts of snowmelt-driven streamflow for watersheds within the Colorado River Basin (CRB) and eastern Great Basin (EGB), across a wide variety of scales. Therefore, the CBRFC and its stakeholders consider snowpack observations to be highly valuable. Observations of fractional snow covered area (fSCA) from satellite-borne instrumentation can better inform both forecasters and water users with respect to subsequent snowmelt runoff, particularly when combined with observations from ground-based station networks and/or airborne platforms. As part of a multi-year collaborative effort, CBRFC has partnered with the Jet Propulsion Laboratory (JPL) under funding from NASA to incorporate observations of fSCA from NASA's Moderate Resolution Imaging Spectroradiometer (MODIS) into the operational CBRFC hydrologic forecasting and modeling process. In the first year of the collaboration, CBRFC and NASA/JPL integrated snow products into the forecasting and decision making processes of the CBRFC and showed preliminary improvement in operational streamflow forecasts. In late 2012, CBRFC and NASA/JPL began retrospective analysis of relationships between the MODIS Snow Covered Area and Grain size (MODSCAG) fSCA and streamflow patterns for several watersheds within the CRB and the EGB. During the 2013 snowmelt runoff season, CBRFC forecasters used MODIS-derived fSCA semi-quantitatively as a binary indicator of the presence or lack of snow. Indication of the presence or lack of snow by MODIS assisted CBRFC forecasters in determining the cause of divergence between modeled and recently observed streamflow. Several examples of improved forecasts from across the CRB and EGB, informed by

  14. Changes in Snowmelt Runoff Timing: Potential Implications for Stream Temperature and Native Salmonid Habitat

    NASA Astrophysics Data System (ADS)

    MacDonald, R.; Boon, S.; Byrne, J. M.; Silins, U.

    2013-12-01

    Atmospheric warming is expected to maintain the trend towards an earlier onset of spring snowmelt across western North America in the future. An advanced spring streamflow peak has important implications for aquatic ecosystems, particularly cold-water salmonids that are sensitive to changes in stream hydrological and thermal regimes. We tested stream temperature sensitivity to atmospheric warming scenarios in a headwater catchment on the eastern slopes of the Rocky Mountains by applying a process-based hydrometeorological and stream temperature model. We used a field study in three thermally and hydrologically distinct catchments to provide context for modelling. Results indicate that stream temperature sensitivity to atmospheric warming is variable and corresponds with changes in streamflow. Predictions of lower spring, higher summer and fall, and lower winter stream temperatures are consistent with field study results. This analysis suggests the thermal habitat of native salmonids could become less suitable under future climatic conditions, favouring non-native species.

  15. Snowmelt discharge characteristics Sierra Nevada, California

    USGS Publications Warehouse

    Peterson, David; Smith, Richard; Stewart, Iris; Knowles, Noah; Soulard, Chris; Hager, Stephen

    2005-01-01

    Alpine snow is an important water resource in California and the western U.S. Three major features of alpine snowmelt are the spring pulse (the first surge in snowmelt-driven river discharge in spring), maximum snowmelt discharge, and base flow (low river discharge supported by groundwater in fall). A long term data set of hydrologic measurements at 24 gage locations in 20 watersheds in the Sierra Nevada was investigated to relate patterns of snowmelt with stream discharge In wet years, the daily variations in snowmelt discharge at all the gage locations in the Sierra Nevada correlate strongly with the centrally located Merced River at Happy Isles, Yosemite National Park (i.e., in 1983, the mean of the 23 correlations was R= 0.93 + 0.09) ; in dry years, however, this correlation breaks down (i.e., in year 1977, R=0.72 + 0.24). A general trend towards earlier snowmelt was found and modeled using correlations with the timing of the spring pulse and the river discharge center of mass. For the 24 river and creek gage locations in this study, the spring pulse appeared to be a more sensitive measure of early snowmelt than the center of mass. The amplitude of maximum daily snowmelt discharge correlates strongly with initial snow water equivalent. Geologic factors, base rock permeability and soil-to-bedrock ratio, influence snowmelt flow pathways. Although both surface and ground water flows and water levels increase in wet years compared to dry years, the increase was greater for surface water in a watershed with relatively impermeable base rock than for surface water in a watershed with highly permeable base rock The relation was the opposite for base flow (ground water). The increase was greater for groundwater in a watershed with permeable rock compared to ground water in a watershed with impermeable rock. A similar, but weaker, surface/groundwater partitioning was observed in relatively impermeable granitic watersheds with differing soil-to-bedrock ratios. The

  16. Streamflow characteristics of small tributaries of Rock Creek, Milk River basin, Montana, base period water years 1983-87

    USGS Publications Warehouse

    Parrett, Charles; Hull, J.A.

    1990-01-01

    Five streamflow-gaging stations were installed in the Rock Creek basin north of the Milk River near Hinsdale, Montana. Streamflow was monitored at these stations and at an existing gaging station upstream on Rock Creek from May 1983 through September 1987. The data collected were used to describe the flow characteristics of four small tributary streams. Annual mean streamflow ranges from 2.8 to 57 cu ft/sec in the mainstem and from 0 to 0.60 cu ft/sec in the tributaries. Monthly mean streamflow ranged from 0 to 528 cu ft/sec in Rock Creek and from zero to 5.3 cu ft/sec in the four tributaries. The six gaged sites show similar patterns of daily mean streamflow during periods of large runoff, but substantial individual variations during periods of lesser runoff. During periods of lesser runoff , the small tributaries may have small daily mean streamflows. At other times, daily mean streamflow at the two mainstem sites decreased downstream. Daily mean streamflow in the tributaries appears to be closely related to daily mean streamflow in the mainstem only during periods of substantial area-wide runoff. Thus, streamflow in the tributaries resulting from local storms or local snowmelt may not contribute to streamflow in the mainstem. (USGS)

  17. Relation of urban land-use and dry-weather storm and snowmelt flow characteristics to stream-water quality, Shunganunga Creek basin, Topeka, Kansas

    USGS Publications Warehouse

    Pope, L.M.; Bevans, H.E.

    1984-01-01

    Water-quality characteristics of streams draining Topeka, Kansas , and the Shunganunga Creek basin were investigated from October , 1979, through November 1981, to determine the effects of runoff from urban areas. Characteristics were determined at six sites and summarized statistically for three streamflow conditions-dry weather, storm, and snowmelt. Median concentrations of trace metals and nutrients were greater in storm streamflow than in dry-weather streamflow. Regression equations were developed to estimate median concentrations of total lead and zinc in storm streamflow from the percentage of drainage area in residential plus commercial land-use areas and from street density. Median concentrations of dissolved sodium, chloride, and solids were considerably greater in snowmelt streamflow than in dry-weather streamflow. Regression equations were also developed to estimate median concentrations of dissolved sodium, chloride, and solids from the summation of percentages of the drainage area in residential, commercial, and industrial land-use areas and from street density. Multiple-regression analysis relating storm-runoff volumes and average constituent concentrations to land-use and storm charactersitcs produced significant relations for storm-runoff volume, total lead, total zinc, and suspended sediment. (USGS)

  18. THE ABCS OF SNOWMELT: A TOPOGRAPHICALLY FACTORIZED ENERGY COMPONENT SNOWMELT MODEL. (R824784)

    EPA Science Inventory

    Because of the crucial role snowmelt plays in many watersheds around the world, it is important to understand and accurately quantify the melt process. As such, numerous mathematical models attempting to describe and predict snowmelt have arisen. There are two main categories of ...

  19. THE ABCS OF SNOWMELT: A TOPOGRAPHICALLY FACTORIZED ENERGY COMPONENT SNOWMELT MODEL. (R824784)

    EPA Science Inventory

    Because of the crucial role snowmelt plays in many watersheds around the world, it is important to understand and accurately quantify the melt process. As such, numerous mathematical models attempting to describe and predict snowmelt have arisen. There are two main categories of ...

  20. Controls on the diurnal streamflow cycles in two subbasins of an alpine headwater catchment

    NASA Astrophysics Data System (ADS)

    Mutzner, Raphael; Weijs, Steven V.; Tarolli, Paolo; Calaf, Marc; Oldroyd, Holly J.; Parlange, Marc B.

    2015-05-01

    In high-altitude alpine catchments, diurnal streamflow cycles are typically dominated by snowmelt or ice melt. Evapotranspiration-induced diurnal streamflow cycles are less observed in these catchments but might happen simultaneously. During a field campaign in the summer 2012 in an alpine catchment in the Swiss Alps (Val Ferret catchment, 20.4 km2, glaciarized area: 2%), we observed a transition in the early season from a snowmelt to an evapotranspiration-induced diurnal streamflow cycle in one of two monitored subbasins. The two different cycles were of comparable amplitudes and the transition happened within a time span of several days. In the second monitored subbasin, we observed an ice melt-dominated diurnal cycle during the entire season due to the presence of a small glacier. Comparisons between ice melt and evapotranspiration cycles showed that the two processes were happening at the same times of day but with a different sign and a different shape. The amplitude of the ice melt cycle decreased exponentially during the season and was larger than the amplitude of the evapotranspiration cycle which was relatively constant during the season. Our study suggests that an evapotranspiration-dominated diurnal streamflow cycle could damp the ice melt-dominated diurnal streamflow cycle. The two types of diurnal streamflow cycles were separated using a method based on the identification of the active riparian area and measurement of evapotranspiration.

  1. Streamflow Outlooks for Southwestern Rivers in a Changing Climate

    NASA Astrophysics Data System (ADS)

    Gutzler, D. S.; Carilli, J.; Norris, J.; O'Shea, J.; Sung, Y.; Salgado, M.

    2016-12-01

    Southwestern rivers are affected by both cold season snow-related processes, and by warm season rainfall and evapotranspiration. Within the North American monsoon region, the importance of rainfall can be especially pronounced, and is projected to become even more important as temperatures rise associated with large-scale climate change. In this presentation we use both historical observations and CMIP projections to examine the relative variability of snowmelt runoff and post-snowmelt hydrologic processes, in the context of assessing annual water supply outlooks and longer term projections of streamflow. Current water supply outlooks are strongly affected by trends in snowpack, and by natural multidecadal fluctuations in winter and spring precipitation, both of which affect the expected value of streamflow expressed in seasonal water supply outlooks. It should be possible to incorporate these processes into seasonal prediction schemes to improve the skill of water supply outlooks. Large interannual fluctuations in summer precipitation also affect flows, especially in tributaries and smaller drainages. This component of hydrologic variability is (at present) largely unpredictable on seasonal time scales and is simulated with relatively low confidence in climate change projections. Monsoon rainfall is also the major process affecting upward surface water and energy fluxes across the arid southwest in summer. On climate change time scales, the effect of increasing temperature on snowpack and ET is projected to become the first-order process responsible for projections of diminished streamflow, subject to continued large interannual and decadal variability of precipitation.

  2. Precipitation-Snowmelt Timing and Snowmelt Augmentation of Large Peak Flow Events, Western Cascades, Oregon

    NASA Astrophysics Data System (ADS)

    Jennings, K. S.; Jones, J. A.

    2014-12-01

    Extreme rain-on-snow floods are known to result from snowmelt coincident with precipitation, but comparatively little is known about the relative timing of these factors within storm events. Cumulative net snowmelt (hourly, from a snowmelt lysimeter) was plotted against precipitation for 26 large storms (> 1-yr return period) over the period 1991-2012 in the transient snow zone of the H.J. Andrews Experimental Forest in the western Cascades of Oregon. The relative timing of precipitation and net snowmelt at the hourly time scale was assessed with wavelet coherence. Five precipitation-net snowmelt response categories were identified: flat; persistent melt; persistent snow accumulation; late melt; and late snow accumulation. Persistent melt events were characterized by increasing cumulative net snowmelt and precipitation and had the highest mean peak flow and water available for runoff. Both the persistent melt and persistent snow accumulation categories had large, contiguous regions of significant wavelet coherence at multiple temporal scales, but pulses of precipitation preceded pulses of snowmelt in the persistent melt events, whereas precipitation was absorbed by the snowpack in the persistent accumulation category. A dewpoint temperature consistently above 0.5°C, elevated wind speeds, and a high fraction of precipitation falling as rain in the persistent melt category facilitated rapid snowmelt rates. During the two extreme rain-on-snow events in the sample, snowmelt was significantly synchronized with precipitation at 1-h to 64-h time scales throughout the 10-day event duration. Event categorization and analysis of wavelet coherence between precipitation and snowmelt can help predict peak discharge magnitude.

  3. Prognostic models based on administrative data alone inadequately predict the survival outcomes for critically ill patients at 180 days post-hospital discharge.

    PubMed

    Bohensky, Megan A; Jolley, Damien; Pilcher, David V; Sundararajan, Vijaya; Evans, Sue; Brand, Caroline A

    2012-08-01

    There is interest in evaluating the quality of critical care by auditing patient outcomes after hospital discharge. Risk adjustment using acuity of illness scores, such as Acute Physiology and Chronic Health Evaluation (APACHE III) scores, derived from clinical databases is commonly performed for in-hospital mortality outcome measures. However, these clinical databases do not routinely track patient outcomes after hospital discharge. Linkage of clinical databases to administrative data sets that maintain records on patient survival after discharge can allow for the measurement of survival outcomes of critical care patients after hospital discharge while using validated risk adjustment methods. The aim of this study was to compare the ability of 4 methods of risk adjustment to predict survival of critically ill patients at 180 days after hospital discharge: one using only variables from an administrative data set, one using only variables from a clinical database, a model using a full range of administrative and clinical variables, and a model using administrative variables plus APACHE III scores. This was a population-based cohort study. The study sample consisted of adult (>15 years of age) residents of Victoria, Australia, admitted to a public hospital intensive care unit between 1 January 2001 and 31 December 2006 (n = 47,312 linked cases). Logistic regression analyses were used to develop the models. The administrative-only model was the poorest predictor of mortality at 180 days after hospital discharge (C = 0.73). The clinical model had substantially better predictive capabilities (C = 0.82), whereas the full-linked model achieved similar performance (C = 0.83). Adding APACHE III scores to the administrative model also had reasonable predictive capabilities (C = 0.83). The addition of APACHE III scores to administrative data substantially improved model performance to the level of the clinical model. Although linking data systems requires some investment

  4. Episodic acidification of Adirondack lakes during snowmelt

    SciTech Connect

    Schaefer, D.A.; Driscoll, C.T.; Van Dreason, R.; Yatsko, C.P.

    1990-07-01

    Maximum values of acid neutralizing capacity (ANC) in Adirondack, New York lake outlets generally occur during summer and autumn. During spring snowmelt, transport of acidic water through acid-sensitive watersheds causes depression of upper lake water ANC. In some systems lake outlet ANC reaches negative values. The authors examined outlet water chemistry from II Adirondack lakes during 1986 and 1987 snowmelts. In these lakes, SO concentrations were diluted during snowmelt and did not depress ANC. For lakes with high baseline ANC values, springtime ANC depressions were primarily accompanied by basic cation dilution. For lakes with low baseline ANC, No increases dominated ANC depressions. Lakes with intermediate baseline ANC were affected by both processes and exhibited larger ANC depressions. Ammonium dilution only affected wetland systems. A model predicting a linear relationship between outlet water ANC minima and autumn ANC was inappropriate. To assess watershed response to episodic acidification, hydrologic flow paths must be considered. (Copyright (c) 1990 by the American Geophysical Union.)

  5. Consequences of early snowmelt in Rocky Mountains

    NASA Astrophysics Data System (ADS)

    Balcerak, Ernie

    2013-01-01

    Snow melted significantly earlier in the Rocky Mountains in 2012 than in previous years, with serious consequences for plants and animals, scientists reported at the AGU Fall Meeting. David Inouye of the University of Maryland, College Park, and the Rocky Mountain Biological Laboratory said that "the timing of winter's end is changing." He has been observing snowmelt dates and flowering of plants at a site at 2900 meters altitude. This year's snowmelt occurred 23 April, whereas the previous year, snow melted 19 June, he reported.

  6. Quantifying effects of climate change on the snowmelt-dominated groundwater resources of northern New England

    USGS Publications Warehouse

    Dudley, Robert W.; Hodgkins, Glenn A.; Shanley, James B.; Mack, Thomas J.

    2010-01-01

    Recent U.S. Geological Survey (USGS) climate studies in New England have shown substantial evidence of hydrologic changes during the last 100 years, including trends toward earlier snowmelt runoff, decreasing occurrence of river ice, and decreasing winter snowpack. These studies are being expanded to include investigation of trends in groundwater levels and fluctuations. Groundwater is an important drinking-water source throughout northern New England (Maine, New Hampshire, and Vermont). The USGS is currently investigating whether or not groundwater recharge from snowmelt and precipitation exhibits historical trends. In addition to trend-testing, groundwater resources also will be analyzed by relating groundwater-level changes to the large year-to-year variability in weather conditions. Introduction The USGS has documented many seasonal climate-related changes in the northeastern United States that have occurred during the last 30 to 150 years. These changes include earlier snowmelt runoff in the late winter and early spring, decreasing duration of ice on rivers and lakes, decreasing ratio of snowfall to total precipitation, and denser and thinner late-winter snowpack. All of these changes are consistent with warming winter and spring air temperatures (Dudley and Hodgkins, 2002; Hodgkins and others, 2002; Huntington and others, 2004; Hodgkins and others, 2005; Hodgkins and Dudley, 2006a; Hodgkins and Dudley, 2006b). Climate-model projections for the Northeast indicate air-temperature warming, earlier snowmelt runoff, increases in annual evaporation, and decreased low streamflows (Hayhoe and others, 2007). The contribution and timing of spring snowmelt to groundwater recharge is particularly important to groundwater resources in the northeastern United States where aquifers typically consist of thin sediments overlying crystalline bedrock with relatively little storage capacity (Mack, 2009). Following spring recharge, groundwater slowly flows into streams throughout

  7. A hydrometric and geochemical approach to test the transmissivity feedback hypothesis during snowmelt

    NASA Astrophysics Data System (ADS)

    Kendall, K. A.; Shanley, J. B.; McDonnell, J. J.

    1999-07-01

    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

  8. Snowmelt Runoff Model (SRM) User's Manual

    USDA-ARS?s Scientific Manuscript database

    This 2008 edition of the User’s Manual presents a new computer program, the Windows Version 1.11 of the Snowmelt Runoff Model (WinSRM). The popular Version 4 is also preserved in the Appendix because it is still in demand to be used within its limits. The Windows version adds new capabilities: it ac...

  9. The effect of frozen soil on snowmelt runoff at Sleepers River, Vermont

    USGS Publications Warehouse

    Shanley, J.B.; Chalmers, A.

    1999-01-01

    Soil frost depth has been monitored at the Sleepers River Research Watershed in northeastern Vermont since 1984. Soil frost develops every winter, particularly in open fields, but its depth varies from year to year in inverse relation to snow depth. During the 15 years of record at a benchmark mid-elevation open site, the annual maximum frost depth varied from 70 to 390 mm. We empirically tested the hypothesis that frozen soil prevents infiltration and recharge, thereby causing an increased runoff ratio (streamflow/(rain + snowmelt)) during the snowmelt hydrograph rise and a decreased runoff ratio during snowmelt recession. The hypothesis was not supported at the 111 km2 W-5 catchment; there was no significant correlation of the runoff ratio with the seasonal maximum frost depth for either the pre-peak or post-peak period. In an analysis of four events, however, the presence of frost promoted a large and somewhat quicker response to rainfall relative to the no-frost condition, although snow cover caused a much greater time-to-peak regardless of frost status. For six years of flow and frost depth measured at the 59 ha agricultural basin W-2, the hypothesis appeared to be supported. The enhancement of runoff due to soil frost is evident on small plots and in extreme events, such as rain on frozen snow-free soil. In the northeastern USA and eastern Canada, the effect is often masked in larger catchments by several confounding factors, including storage of meltwater in the snowpack, variability in snowmelt timing due to elevational and aspect differences, interspersed forested land where frost may be absent, and the timing of soil thawing relative to the runoff peak.Soil frost depth has been monitored at the Sleepers River Research Watershed in northeastern Vermont since 1984. Soil frost develops every winter, particularly in open fields, but its depth varies greatly from year to year in inverse relation to snow depth. During the 15 years of record at a benchmark mid

  10. Snowmelt pollutant removal in bioretention areas.

    PubMed

    Muthanna, Tone Merete; Viklander, Maria; Blecken, Godecke; Thorolfsson, Sveinn T

    2007-10-01

    Snow accumulating in urban areas and alongside roads can accumulate high pollutant loads and the subsequent snowmelt can produce high pollutant loads in receiving waters. This paper examines the treatment of roadside snowmelt in bioretention with respect to pollutant removal, pollutant pathways, and major sinks. Bioretention was used to treat snowmelt from three types of urban roads in Trondheim, Norway: residential, medium, and roads with high-density traffic. Metal retention in bioretention boxes had a mass reduction in zinc, copper, lead, and cadmium in the range of 89-99%, and a decrease in outflow concentrations in the range 81-99%. Cadmium was only measured in the water samples, while the other three metals were traced through the system to identify the main sinks. The top mulch layer was the largest sink for the retained metals, with up to 74% of the zinc retained in this mulch layer. The plant metal uptakes were only 2-8% of the total metal retention; however, the plants still play an important role with respect to root zone development and regeneration, which fosters infiltration and reduces the outflow load. Dissolved pollutants in snowmelt tend to be removed with the first flush of meltwater, creating an enrichment ratio with respect to the average pollutant concentrations in the snow. The effect of this enrichment ratio was examined through the bioretention system, and found to be less predominant than that typically reported for untreated snowmelt. The enrichment factors were in the range of 0.65-1.51 for the studied metals.

  11. Verification of temperature, precipitation, and streamflow forecasts from the NOAA/NWS Hydrologic Ensemble Forecast Service (HEFS): 2. Streamflow verification

    NASA Astrophysics Data System (ADS)

    Brown, James D.; He, Minxue; Regonda, Satish; Wu, Limin; Lee, Haksu; Seo, Dong-Jun

    2014-11-01

    -GFS accounts for the majority of skill in the CNRFC basins. This is associated with the greater predictability of large storms in the North Coast Ranges during the winter months. In CBRFC, much of the skill in the streamflow forecasts originates from the hydrologic modeling and the EnsPost, particularly during the snowmelt period. In AB- and MA-RFCs, the contributions from the MEFP and the EnsPost are more variable. This paper summarizes the verification results, describes the expected performance and limitations of the HEFS for short- to medium-range streamflow forecasting, and provides recommendations for future research.

  12. An approach for modelling snowcover ablation and snowmelt runoff in cold region environments

    NASA Astrophysics Data System (ADS)

    Dornes, Pablo Fernando

    Reliable hydrological model simulations are the result of numerous complex interactions among hydrological inputs, landscape properties, and initial conditions. Determination of the effects of these factors is one of the main challenges in hydrological modelling. This situation becomes even more difficult in cold regions due to the ungauged nature of subarctic and arctic environments. This research work is an attempt to apply a new approach for modelling snowcover ablation and snowmelt runoff in complex subarctic environments with limited data while retaining integrity in the process representations. The modelling strategy is based on the incorporation of both detailed process understanding and inputs along with information gained from observations of basin-wide streamflow phenomenon; essentially a combination of deductive and inductive approaches. The study was conducted in the Wolf Creek Research Basin, Yukon Territory, using three models, a small-scale physically based hydrological model, a land surface scheme, and a land surface hydrological model. The spatial representation was based on previous research studies and observations, and was accomplished by incorporating landscape units, defined according to topography and vegetation, as the spatial model elements. Comparisons between distributed and aggregated modelling approaches showed that simulations incorporating distributed initial snowcover and corrected solar radiation were able to properly simulate snowcover ablation and snowmelt runoff whereas the aggregated modelling approaches were unable to represent the differential snowmelt rates and complex snowmelt runoff dynamics. Similarly, the inclusion of spatially distributed information in a land surface scheme clearly improved simulations of snowcover ablation. Application of the same modelling approach at a larger scale using the same landscape based parameterisation showed satisfactory results in simulating snowcover ablation and snowmelt runoff with

  13. Spatially distributed energy balance snowmelt modelling in a mountainous river basin: estimation of meteorological inputs and verification of model results

    NASA Astrophysics Data System (ADS)

    Garen, David C.; Marks, Danny

    2005-12-01

    A spatially distributed energy balance snowmelt model has been applied to a 2150 km 2 drainage basin in the Boise River, ID, USA, to simulate the accumulation and melt of the snowpack for the years 1998-2000. The simulation was run at a 3 h time step and a spatial resolution of 250 m. Spatial field time series of meteorological input data were obtained using various spatial interpolation and simulation methods. The variables include precipitation, air temperature, dew point temperature, wind speed, and solar and thermal radiation. The goal was to use readily available data and relatively straightforward, yet physically meaningful, methods to develop the spatial fields. With these meteorological fields as input, the simulated fields of snow water equivalent, snow depth, and snow covered area reproduce observations very well. The simulated snowmelt fields are also used as input to a spatially distributed hydrologic model to estimate streamflow. This gives an additional verification of the snowmelt modelling results as well as provides a linkage of the two models to generate hydrographs for water management information. This project is a demonstration of spatially distributed energy balance snowmelt modelling in a large mountainous catchment using data from existing meteorological networks. This capability then suggests the potential for developing new spatial hydrologic informational products and the possibility of improving the accuracy of the prediction of hydrologic processes for water and natural resources management.

  14. Towards a tracer-based conceptualization of meltwater dynamics and streamflow response in a glacierized catchment

    NASA Astrophysics Data System (ADS)

    Penna, Daniele; Engel, Michael; Bertoldi, Giacomo; Comiti, Francesco

    2017-01-01

    Multiple water sources and the physiographic heterogeneity of glacierized catchments hamper a complete conceptualization of runoff response to meltwater dynamics. In this study, we used environmental tracers (stable isotopes of water and electrical conductivity) to obtain new insight into the hydrology of glacierized catchments, using the Saldur River catchment, Italian Alps, as a pilot site. We analysed the controls on the spatial and temporal patterns of the tracer signature in the main stream, its selected tributaries, shallow groundwater, snowmelt and glacier melt over a 3-year period. We found that stream water electrical conductivity and isotopic composition showed consistent patterns in snowmelt-dominated periods, whereas the streamflow contribution of glacier melt altered the correlations between the two tracers. By applying two- and three-component mixing models, we quantified the seasonally variable proportion of groundwater, snowmelt and glacier melt at different locations along the stream. We provided four model scenarios based on different tracer signatures of the end-members; the highest contributions of snowmelt to streamflow occurred in late spring-early summer and ranged between 70 and 79 %, according to different scenarios, whereas the largest inputs by glacier melt were observed in mid-summer, and ranged between 57 and 69 %. In addition to the identification of the main sources of uncertainty, we demonstrated how a careful sampling design is critical in order to avoid underestimation of the meltwater component in streamflow. The results of this study supported the development of a conceptual model of streamflow response to meltwater dynamics in the Saldur catchment, which is likely valid for other glacierized catchments worldwide.

  15. 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

  16. Controls on diurnal streamflow cycles in a high altitude catchment in the Swiss Alps

    NASA Astrophysics Data System (ADS)

    Mutzner, R.; Weijs, S. V.; Tarolli, P.; Calaf, M.; Oldroyd, H. J.; Parlange, M. B.

    2014-12-01

    The study of streamflow diurnal cycles is of primary importance to understand hydrological processes happening at various spatial scales. In high altitude alpine catchments, streamflow diurnal cycles are typically dominated by snow or icemelt. During a field campaign in the summer 2012 in a small catchment in the Swiss Alps (Val Ferret catchment, draining area of 20.4 km2, mean altitude of 2423 m above sea level (asl), ranging from 1773 m to 3206 m asl, glaciarized area: 2%), we observed streamflow diurnal cycles throughout the season in two monitored sub-basins of the watershed. To study in detail the diurnal cycles, we make use of a wireless network of meteorological stations, time-lapse photography, a fully equipped energy-balance station and water electrical conductivity monitored at the gauging stations. In the first sub-basin, we observed a transition from a snowmelt to an evapotranspiration induced diurnal streamflow cycle. In the second sub-basin, we observed a snowmelt/icemelt dominated diurnal cycle during the entire season due to the presence of a small glacier. Comparisons between icemelt and evapotranspiration cycles showed that the two processes were happening at the same times of day but with a different sign. The amplitude of the icemelt cycle decreased exponentially during the season and was larger than of the amplitude of the evapotranspiration cycle which was relatively constant during the season. A conceptual model was applied to estimate the effect of evapotranspiration on the diurnal streamflow cycle in the icemelt dominated sub-basin. The model makes use of the latent heat measured at the energy balance station, the streamflow loss due to evapotranspiration and the computation of active evapotranspiration areas. Our study suggests that evapotranspiration from the riparian area damps the icemelt-diurnal streamflow cycle resulting in a possible underestimation of glacier mass changes.

  17. Relationship Between Satellite-Derived Snow Cover and Snowmelt-Runoff Timing and Stream Power in the Wind River Range, Wyoming

    NASA Technical Reports Server (NTRS)

    Hall, Dorothy K.; Foster, James L.; Riggs, George A.; DiGirolano, Nocolo E.

    2010-01-01

    Earlier onset of springtime weather including earlier snowmelt has been documented in the western United States over at least the last 50 years. Because the majority (>70%) of the water supply in the western U.S. comes from snowmelt, analysis of the declining spring snowpack (and shrinking glaciers) has important implications for streamflow management. The amount of water in a snowpack influences stream discharge which can also influence erosion and sediment transport by changing stream power, or the rate at which a stream can do work such as move sediment and erode the stream bed. The focus of this work is the Wind River Range (WRR) in west-central Wyoming. Ten years of Moderate-Resolution Imaging Spectroradiometer (MODIS) snow-cover, cloud- gap-filled (CGF) map products and 30 years of discharge and meteorological station a are studied. Streamflow data from six streams in the WRR drainage basins show lower annual discharge and earlier snowmelt in the decade of the 2000s than in the previous three decades, though no trend of either lower streamflow or earlier snowmelt was observed using MODIS snow-cover maps within the decade of the 2000s. Results show a statistically-significant trend at the 95% confidence level (or higher) of increasing weekly maximum air temperature (for three out of the five meteorological stations studied) in the decade of the 1970s, and also for the 40-year study period. MODIS- derived snow cover (percent of basin covered) measured on 30 April explains over 89% of the variance in discharge for maximum monthly streamflow in the decade of the 2000s using Spearman rank correlation analysis. We also investigated stream power for Bull Lake Creek Above Bull Lake from 1970 to 2009; a statistically-significant trend toward reduced stream power was found (significant at the 90% confidence level). Observed changes in streamflow and stream power may be related to increasing weekly maximum air temperature measured during the 40-year study period. The

  18. Relationship Between Satellite-Derived Snow Cover and Snowmelt-Runoff Timing and Stream Power in the Wind River Range, Wyoming

    NASA Technical Reports Server (NTRS)

    Hall, Dorothy K.; Foster, James L.; DiGirolamo, Nicolo E.; Riggs, George A.

    2010-01-01

    Earlier onset of springtime weather including earlier snowmelt has been documented in the western United States over at least the last 50 years. Because the majority (>70%) of the water supply in the western U.S. comes from snowmelt, analysis of the declining spring snowpack (and shrinking glaciers) has important implications for streamflow management. The amount of water in a snowpack influences stream discharge which can also influence erosion and sediment transport by changing stream power, or the rate at which a stream can do work such as move sediment and erode the stream bed. The focus of this work is the Wind River Range (WRR) in west-central Wyoming. Ten years of Moderate-Resolution Imaging Spectroradiometer (MODIS) snow-cover, cloud- gap-filled (CGF) map products and 30 years of discharge and meteorological station data are studied. Streamflow data from six streams in the WRR drainage basins show lower annual discharge and earlier snowmelt in the decade of the 2000s than in the previous three decades, though no trend of either lower streamflow or earlier snowmelt was observed using MODIS snow-cover maps within the decade of the 2000s. Results show a statistically-significant trend at the 95% confidence level (or higher) of increasing weekly maximum air temperature (for three out of the five meteorological stations studied) in the decade of the 1970s, and also for the 40-year study period. MODIS-derived snow cover (percent of basin covered) measured on 30 April explains over 89% of the variance in discharge for maximum monthly streamflow in the decade of the 2000s using Spearman rank correlation analysis. We also investigated stream power for Bull Lake Creek Above Bull Lake from 1970 to 2009; a statistically-significant end toward reduced stream power was found (significant at the 90% confidence level). Observed changes in streamflow and stream power may be related to increasing weekly maximum air temperature measured during the 40-year study period. The

  19. Relating Snowpack and Snowmelt in Weather Modified Watersheds

    NASA Astrophysics Data System (ADS)

    Tootle, G. A.; Pelle, A.; Oubeidillah, A.; Kerr, G.

    2014-12-01

    A 2008 editorial in Natureentitled "Change in the weather," it is stated that "a renewed push for scientific research into weather-modification technologies is long overdue." The editorial continues with "Today's rain-makers struggle with their own credibility issues. They do have well established methods for seeding clouds….. weather-modification supporters face a perceived negative bias in the scientific community….. There has yet to be the definitive experiment that settles exactly how well cloud seeding… works (or not)." The editorial concludes with "Other countries, such as the United States, have simply given up; the most promising experiment in America is run not by the federal government but by the state of Wyoming....which is being evaluated by experts from the National Center for Atmospheric Research (NCAR). That's the type of targeted and rigorous study that needs to be done in weather modification, but it took Wyoming to do it." The motivation for weather modification operations is to increase water supply (streamflow) due to increased snowpack. NCAR will complete their evaluation in Fall 2014 that will provide, with uncertainty, the anticipated increase (percent) in snowpack due to cloud seeding. The majority of the cloud seeding for the Wyoming Weather Modification Pilot Project was performed in the North Platte River Basin (NPRB). Researchers from the University of Wyoming, in cooperation with NCAR, analyzed historic meteorological data for the cloud seeding season (November 15th to April 15th) for eight years (2001-2008) to determine "seedable" periods. Using this data combined with the anticipated increase (percent with uncertainty), University of Alabama researchers developed two models (statistical and hydrologic) for the North Brush Creek watershed which is located within the NPRB. The statistical model related snowpack (Snow Water Equivalent) from SNOTEL stations to snowmelt using the Partial Least Squares Regression technique. The

  20. Changes in the magnitude of annual and monthly streamflows in New England, 1902-2002

    USGS Publications Warehouse

    Hodgkins, Glenn A.; Dudley, Robert W.

    2005-01-01

    Selected annual and monthly streamflow statistics for 27 streamflow-gaging stations in New England were computed and tested for changes over time. These 27 stations were considered to be free of substantial human influences such as regulation, diversion, and land use-changes and have an average of 71 years of record. The longest streamflow record extended from 1902 to 2002. March mean streamflows increased significantly over time (Mann-Kendall test, p < 0.1) at 14 streamflow-gaging stations in northern New England, primarily in northern or mountainous sections of Maine, New Hampshire, and Vermont. March mean flows increased by 76 to 185 percent at the seven stations with the longest continuous records in areas of New England with the largest seasonal snowpack depths. These streamflow-gaging stations had continuous records from the late 1920's and the early 1930s through 2002. May mean streamflows significantly decreased at 10 stations in northern or mountainous sections of Maine and New Hampshire. May mean flows decreased by 9 to 46 percent at the seven stations with the longest continuous records. Despite the fact that March percentage increases were much larger than May percentage decreases, March streamflow increases (in cubic feet per second) were smaller than May decreases, except at one streamflow-gaging station. Increased March and April air temperatures over time may have caused earlier snowmelt and thus increased streamflows in March and decreased streamflows in May. There were no significant changes over time in annual mean streamflows at the 27 stations; however, there were significant increases over time in various annual percentile streamflows (minimum, 25th percentile, median, 75th percentile, or maximum flows) at 22 of the stations. This indicates that flows increased over time at many streams in New England, but the increase was not enough to have caused significant changes in annual mean flows. October mean streamflows increased significantly at

  1. Stream water hydrochemistry as an indicator of carbon flow paths in Finnish peatland catchments during a spring snowmelt event.

    PubMed

    Dinsmore, Kerry J; Billett, Michael F; Dyson, Kirstie E; Harvey, Frank; Thomson, Amanda M; Piirainen, Sirpa; Kortelainen, Pirkko

    2011-10-15

    Extreme hydrological events are known to contribute significantly to total annual carbon export, the largest of which in Arctic and boreal catchments is spring snowmelt. Whilst previous work has quantified the export of carbon during snowmelt, the source of the carbon remains unclear. Here we use cation hydrochemistry to trace the primary flowpaths which govern the export of carbon during the snowmelt period; specifically we aim to examine the importance of snowpack meltwater to catchment carbon export. The study was carried out in two forested peatland (drained and undrained) catchments in Eastern Finland. Both catchments were characterised by base-poor stream water chemistry, with cation concentrations generally decreasing in response to increasing discharge. Streamflow during the snowmelt period was best described as a mixture of three sources: pre-event water, snowpack meltwater and a third dilute component we attribute to the upper snow layer which was chemically similar to recent precipitation. Over the study period, pre-event water contributed 32% and 43% of the total stream runoff in Välipuro (undrained) and Suopuro (drained), respectively. The results also suggest a greater near-surface throughflow component in Suopuro, the drained catchment, prior to snowmelt. CO(2) and DOC concentrations correlated positively with cation concentrations in both catchments indicating a common, peat/groundwater flowpath. CH(4) concentrations were significantly higher in the drained catchment and appeared to be transported in near-surface throughflow. Meltwater from the snowpack represented an important source of stream water CO(2) in both catchments, contributing up to 49% of total downstream CO(2) export during the study period. We conclude that the snowpack represents a potentially important, and often overlooked, transient carbon store in boreal snow-covered catchments.

  2. Application and Evaluation of a Snowmelt Runoff Model in the Tamor River Basin, Eastern Himalaya Using a Markov Chain Monte Carlo (MCMC) Data Assimilation Approach

    NASA Technical Reports Server (NTRS)

    Panday, Prajjwal K.; Williams, Christopher A.; Frey, Karen E.; Brown, Molly E.

    2013-01-01

    Previous studies have drawn attention to substantial hydrological changes taking place in mountainous watersheds where hydrology is dominated by cryospheric processes. Modelling is an important tool for understanding these changes but is particularly challenging in mountainous terrain owing to scarcity of ground observations and uncertainty of model parameters across space and time. This study utilizes a Markov Chain Monte Carlo data assimilation approach to examine and evaluate the performance of a conceptual, degree-day snowmelt runoff model applied in the Tamor River basin in the eastern Nepalese Himalaya. The snowmelt runoff model is calibrated using daily streamflow from 2002 to 2006 with fairly high accuracy (average Nash-Sutcliffe metric approx. 0.84, annual volume bias <3%). The Markov Chain Monte Carlo approach constrains the parameters to which the model is most sensitive (e.g. lapse rate and recession coefficient) and maximizes model fit and performance. Model simulated streamflow using an interpolated precipitation data set decreases the fractional contribution from rainfall compared with simulations using observed station precipitation. The average snowmelt contribution to total runoff in the Tamor River basin for the 2002-2006 period is estimated to be 29.7+/-2.9% (which includes 4.2+/-0.9% from snowfall that promptly melts), whereas 70.3+/-2.6% is attributed to contributions from rainfall. On average, the elevation zone in the 4000-5500m range contributes the most to basin runoff, averaging 56.9+/-3.6% of all snowmelt input and 28.9+/-1.1% of all rainfall input to runoff. Model simulated streamflow using an interpolated precipitation data set decreases the fractional contribution from rainfall versus snowmelt compared with simulations using observed station precipitation. Model experiments indicate that the hydrograph itself does not constrain estimates of snowmelt versus rainfall contributions to total outflow but that this derives from the degree

  3. Precipitation-Runoff Simulations of Current and Natural Streamflow Conditions in the Methow River Basin, Washington

    USGS Publications Warehouse

    Ely, D. Matthew

    2003-01-01

    Management of the water resources of the Methow River Basin is changing in response to the listing of three species of fish under the Endangered Species Act and the Washington State-legislated watershed-planning process. This report describes the construction and calibration of an enhanced precipitation-runoff model for the Methow River Basin and evaluates the model as a predictive tool for assessing the current and natural streamflow conditions. This study builds upon a previous precipitation-runoff model for the Methow River Basin and validates the current model using a new, more extensive streamflow data network. The major enhancement was the simulation of current flow conditions with the addition of irrigation diversions, returns, and application. The Geographic Information System Weasel characterized the physical properties of the basin and the Modular Modeling System, using the Precipitation-Runoff Modeling System, simulated the hydrologic flow. Streamflow was simulated for water years 1992-2001 to calibrate the model to measured streamflows. A sensitivity analysis was completed using nonlinear regression to determine hydrologic parameters pertinent to the modeling results. Simulated and measured streamflow generally showed close agreement, especially during spring runoff from snowmelt. Low-flow or baseflow periods, most restrictive to fish habitation, were simulated reasonably well yet possessed the most uncertainty. Simulations of annual mean streamflow as a percentage of measured annual mean streamflow for the 10-year calibration period at six of the seven streamflow-gaging stations ranged from -35.2 to +26.2 percent, with 65 percent of the simulated values within 15 percent. One station was intentionally calibrated to over-simulate discharge (simulated discharge greater than measured discharge) in order to compensate for observed channel losses not simulated by the model. Simulation of water years 1960-2001 demonstrated great variability in monthly

  4. A Hybrid Architecture of Neural Networks for Daily Streamflow Forecasting

    NASA Astrophysics Data System (ADS)

    Moradkhani, H.

    2001-12-01

    Streamflow forecasting has always been a challenging task for water resources engineers and managers and the major component of water resources system control. For years numerous techniques have been suggested and employed for streamflow forecasting. Computational Neural Networks (NNs), which are capable of recognizing hidden patterns in data, have recently become popular in many hydrologic applications. In this study, hybrid NN is developed for one step ahead forecasting of daily streamflow. Radial Basis Function (RBF) composed of a group of Gausian functions is used in conjunction with Self-Organizing Feature Map (SOFM) used in data classification. RBF transfers those classified input variables into the desired output estimate. Eight years of daily rainfall, streamflow, and temperature in Salt River basin were used for calibration and validation. Since 60%-80% of the water supply produced by the basin comes in the form of snow, further consideration of the existing time delay of snow melting process in the basin to the watershed outlet is important. Therefore two separated settings were considered in this simulation: the first one only includes several short-term daily rainfall and streamflow in the input sequence; the second setting, on the other hand, includes a longer time period (three-months) of temperature data sequence. Various statistical analyses, such as root mean square error, bias estimate, noise to signal ratio, and correlation coefficients of estimates and observations, were done to evaluate the forecast models. The preliminary results show that the accuracy of the model once considering the long-term effect of the snowmelt is conspicuous with respect to short-term effect. The effectiveness of the proposed and current operational models is evaluated.

  5. Characterization of hydrologic inputs and streamflow pathways in headwater catchments of Boulder Creek Watershed, Colorado

    NASA Astrophysics Data System (ADS)

    Cowie, R. M.; Williams, M. W.; Mills, T. J.

    2012-12-01

    Streamflow pathways were investigated using isotopic and geochemical tracers in two gauged headwater catchments located at different elevations within the forested area of Boulder Creek Watershed, Colorado. Using diagnostic tools of mixing models indicates that both catchments fit reasonable well to a 1-D (two endmember) model for streamflow generation. End member mixing analysis (EMMA) suggests that streamflow at the lower elevation Gordon Gulch catchment (mean elevation 2627 m) was a combination of shallow subsurface flow and groundwater with limited influence from direct runoff. Steamflow at the higher elevation Como Creek catchment (mean elevation 3230 m) was a combination of runoff from snowmelt and groundwater. During the study period the total annual precipitation and the amount of precipitation falling as snow increased with elevation from 456 mm (41% snow) at Gordon Gulch to 804 mm (71% snow) at Como Creek. The resulting increase in winter snow accumulation at Como Creek demonstrates differences in timing and magnitude of hydrologic inputs between the two catchments and provides a potential driver for the differences in streamflow pathways. These results highlight the importance of understanding variations in streamflow pathways in relation to climatic variations across headwater mountain catchments. The broader impacts of streamflow pathway variations on steam nutrients will also be addressed.

  6. Climate change impacts on streamflow and subbasin-scale hydrology in the Upper Colorado River Basin.

    PubMed

    Ficklin, Darren L; Stewart, Iris T; Maurer, Edwin P

    2013-01-01

    In the Upper Colorado River Basin (UCRB), the principal source of water in the southwestern U.S., demand exceeds supply in most years, and will likely continue to rise. While General Circulation Models (GCMs) project surface temperature warming by 3.5 to 5.6°C for the area, precipitation projections are variable, with no wetter or drier consensus. We assess the impacts of projected 21(st) century climatic changes on subbasins in the UCRB using the Soil and Water Assessment Tool, for all hydrologic components (snowmelt, evapotranspiration, surface runoff, subsurface runoff, and streamflow), and for 16 GCMs under the A2 emission scenario. Over the GCM ensemble, our simulations project median Spring streamflow declines of 36% by the end of the 21(st) century, with increases more likely at higher elevations, and an overall range of -100 to +68%. Additionally, our results indicated Summer streamflow declines with median decreases of 46%, and an overall range of -100 to +22%. Analysis of hydrologic components indicates large spatial and temporal changes throughout the UCRB, with large snowmelt declines and temporal shifts in most hydrologic components. Warmer temperatures increase average annual evapotranspiration by ∼23%, with shifting seasonal soil moisture availability driving these increases in late Winter and early Spring. For the high-elevation water-generating regions, modest precipitation decreases result in an even greater water yield decrease with less available snowmelt. Precipitation increases with modest warming do not translate into the same magnitude of water-yield increases due to slight decreases in snowmelt and increases in evapotranspiration. For these basins, whether modest warming is associated with precipitation decreases or increases, continued rising temperatures may make drier futures. Subsequently, many subbasins are projected to turn from semi-arid to arid conditions by the 2080 s. In conclusion, water availability in the UCRB could

  7. Climate Change Impacts on Streamflow and Subbasin-Scale Hydrology in the Upper Colorado River Basin

    PubMed Central

    Ficklin, Darren L.; Stewart, Iris T.; Maurer, Edwin P.

    2013-01-01

    In the Upper Colorado River Basin (UCRB), the principal source of water in the southwestern U.S., demand exceeds supply in most years, and will likely continue to rise. While General Circulation Models (GCMs) project surface temperature warming by 3.5 to 5.6°C for the area, precipitation projections are variable, with no wetter or drier consensus. We assess the impacts of projected 21st century climatic changes on subbasins in the UCRB using the Soil and Water Assessment Tool, for all hydrologic components (snowmelt, evapotranspiration, surface runoff, subsurface runoff, and streamflow), and for 16 GCMs under the A2 emission scenario. Over the GCM ensemble, our simulations project median Spring streamflow declines of 36% by the end of the 21st century, with increases more likely at higher elevations, and an overall range of −100 to +68%. Additionally, our results indicated Summer streamflow declines with median decreases of 46%, and an overall range of −100 to +22%. Analysis of hydrologic components indicates large spatial and temporal changes throughout the UCRB, with large snowmelt declines and temporal shifts in most hydrologic components. Warmer temperatures increase average annual evapotranspiration by ∼23%, with shifting seasonal soil moisture availability driving these increases in late Winter and early Spring. For the high-elevation water-generating regions, modest precipitation decreases result in an even greater water yield decrease with less available snowmelt. Precipitation increases with modest warming do not translate into the same magnitude of water-yield increases due to slight decreases in snowmelt and increases in evapotranspiration. For these basins, whether modest warming is associated with precipitation decreases or increases, continued rising temperatures may make drier futures. Subsequently, many subbasins are projected to turn from semi-arid to arid conditions by the 2080 s. In conclusion, water availability in the UCRB could

  8. Seasonal streamflow forecasts in a semi-arid Andean watershed using remotely sensed snow cover data

    NASA Astrophysics Data System (ADS)

    Cartes, M.; McPhee, J.; Vargas, X.

    2009-04-01

    Forecasts of monthly streamflow during the snowmelt season are highly relevant for real-time decision making such as hydropower production scheduling, irrigation planning, and water transfers in market-driven water resource systems. The Chilean water bureau issues such forecasts, for a number of snowmelt-driven watersheds in northern and central Chile, based on measurements from a sparse network of snow course stations. This research aims at improving the accuracy of the government-issued seasonal forecasts by combining streamflow data and remotely sensed snow cover information through a recurrent neural network (RNN). The snow cover area (SCA) obtained from MODIS-Surface Reflectance product (MOD09) and the Normalized Differentiation Snow Index (NDSI), from 2000-2008 period, allow us to understand the variation of the snowmelt and accumulation processes in six different basins located in central Chile (32,5° - 34,5° south latitude; 69,5° -70,5° west longitude). For the three basins located at higher altitudes (> 1800 m.s.l.), after applying a cross-correlation procedure we determined a strong relation (r > 0.7) between SCA and the seasonal hydrograph, lagged around 4 months. The basin SCA, the NDSI at specific points inside the basin and past basin streamflow data are input to the RNN for recognizing the pattern variation of seasonal hydrograph through supervised learning. The determination coefficients for the validation period (r2 > 0.6) indicate a good support for the application of this methodology in normal-humid hydrological years. Particularly for the dryer years we obtain a considerable overestimation (around 30%) of the monthly snowmelt runoff. These results are limited by the availability of data for different types (dry, normal or humid) of hydrological years.

  9. Effects of asynchronous snowmelt on flushing of dissolved organic carbon: A mixing model approach

    USGS Publications Warehouse

    Boyer, E.W.; Hornberger, G.M.; Bencala, K.E.; McKnight, Diane M.

    2000-01-01

    In many snowmelt-dominated catchments, stream dissolved organic carbon (DOC) levels typically increase rapidly as spring melt commences, peak before maximum discharge, and decrease quickly as melting continues. We present data from Deer Creek (Summit County, CO) that shows this distinctive flushing response of DOC during snowmelt runoff, with DOC stored in landscape soils flushed to the stream in response to infiltrating melt waters. Our prior studies show that asynchronous melting of the snowpack across the landscape causes the spring DOC flush to be initiated at different times throughout the catchment. In this study we quantify characteristics of the asynchronous melt and its effect on DOC flushing. We investigated whether a simple mixing model can be used to capture the essentials of the asynchronous melting of a seasonal snowpack and its controls on DOC transport. We divided the catchment into zones of aspect and elevation, which largely determine spatial and temporal variations in the distribution of snow. TOPMODEL was used to simulate the hydrology in each zone, and the simulated flow paths were routed through a simple DOC mixing model to predict contributions of DOC to the stream. The zonal responses were aggregated to give a predicted response of hydrology and DOC fluxes for the entire catchment. Our results indicate that asynchronous melting-which determines the timing of contributions of discharge and DOC to streamflow from different areas of the landscape-can be quantified using a simple modeling approach. Copyright ?? 2000 John Wiley & Sons, Ltd.

  10. Snowmelt hydrograph interpretation: Revealing watershed scale hydrologic characteristics of the Yellowstone volcanic plateau

    NASA Astrophysics Data System (ADS)

    Payton Gardner, W.; Susong, David D.; Kip Solomon, D.; Heasler, Henry

    2010-03-01

    SummarySnowmelt hydrograph analysis and groundwater age dates of cool water springs on the Yellowstone volcanic plateau provide evidence of high volumes of groundwater circulation in watersheds comprised of quaternary Yellowstone volcanics. Ratios of maximum to minimum mean daily discharge and average recession indices are calculated for watersheds within and surrounding the Yellowstone volcanic plateau. A model for snowmelt recession is used to separate groundwater discharge from overland runoff, and compare groundwater systems. Hydrograph signal interpretation is corroborated with chlorofluorocarbon (CFC) and tritium concentrations in cool water springs on the Yellowstone volcanic plateau. Hydrograph parameters show a spatial pattern correlated with watershed geology. Watersheds comprised dominantly of quaternary Yellowstone volcanics are characterized by slow streamflow recession, low maximum to minimum flow ratios. Cool springs sampled within the Park contain CFC's and tritium and have apparent CFC age dates that range from about 50 years to modern. Watersheds comprised of quaternary Yellowstone volcanics have a large volume of active groundwater circulation. A large, advecting groundwater field would be the dominant mechanism for mass and energy transport in the shallow crust of the Yellowstone volcanic plateau, and thus control the Yellowstone hydrothermal system.

  11. Snowmelt hydrograph interpretation: Revealing watershed scale hydrologic characteristics of the Yellowstone volcanic plateau

    USGS Publications Warehouse

    Payton, Gardner W.; Susong, D.D.; Kip, Solomon D.; Heasler, H.

    2010-01-01

    Snowmelt hydrograph analysis and groundwater age dates of cool water springs on the Yellowstone volcanic plateau provide evidence of high volumes of groundwater circulation in watersheds comprised of quaternary Yellowstone volcanics. Ratios of maximum to minimum mean daily discharge and average recession indices are calculated for watersheds within and surrounding the Yellowstone volcanic plateau. A model for snowmelt recession is used to separate groundwater discharge from overland runoff, and compare groundwater systems. Hydrograph signal interpretation is corroborated with chlorofluorocarbon (CFC) and tritium concentrations in cool water springs on the Yellowstone volcanic plateau. Hydrograph parameters show a spatial pattern correlated with watershed geology. Watersheds comprised dominantly of quaternary Yellowstone volcanics are characterized by slow streamflow recession, low maximum to minimum flow ratios. Cool springs sampled within the Park contain CFC's and tritium and have apparent CFC age dates that range from about 50 years to modern. Watersheds comprised of quaternary Yellowstone volcanics have a large volume of active groundwater circulation. A large, advecting groundwater field would be the dominant mechanism for mass and energy transport in the shallow crust of the Yellowstone volcanic plateau, and thus control the Yellowstone hydrothermal system. ?? 2009 Elsevier B.V.

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

    USGS Publications Warehouse

    Curran, Janet H.

    2012-01-01

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

  13. Streamflows at record highs

    NASA Astrophysics Data System (ADS)

    Streamflow was reported well above average in more than half the country during May, with flows at or near record levels for the month in 22 states, according to the U.S. Geological Survey (USGS), Department of the Interior.USGS hydrologists said that above average flow was reported at 98 of the 173 USGS key index gauging stations used in their monthly check on surface- and ground-water conditions. High flows were most prevalent in the Mississippi River basin states and in the east, with the exception of Maine, South Carolina, and Georgia. Below-average streamflow occurred in the Pacific northwest and in small scattered areas in Colorado, Kansas, Texas, and Minnesota.

  14. Skill Analysis of Seasonal Hydrologic Streamflow Forecasting for the Upper Zambezi, Africa

    NASA Astrophysics Data System (ADS)

    Valdés-Pineda, R.; Valdes, J. B.; Serrat-Capdevila, A.; Wi, S.; Demaria, E. M.; Roberts, J. B.; Robertson, F. R.

    2016-12-01

    Seasonal Hydrological Streamflow Forecasting (SHSF) is a powerful tool aimed to provide information to water resources managers. SHSF incorporates information provided by coupled atmosphere-ocean-land general circulation models (CGCMs) into hydrologic models to produce seasonal (up to 180 days) daily streamflow forecasts. In this research the forecasting skills of four distributed hydrologic models: the HyMod model, the HBV model; the Variable Infiltration Capacity (VIC) model; and the Sacramento Soil Moisture Accounting (SAC-SMA) are evaluated for the period 2000-2016 in the Upper Zambezi River Basin (UZRB). Seasonal streamflow forecasts for the UZRB are produced using seasonal forecasts of precipitation and temperature obtained from the North American Multi-Model Ensemble (NMME). A stratified sampling of NMME scenarios is used to provide uncertainty levels of the forecasts; and the impact of the initial conditions over the seasonal predictions is also analyzed and discussed. The ensemble of the multi-model satellite based streamflow forecasts will serve as decision support tools for managing water resources in the Zambezi River basin using a website-based platform developed as a collaborative effort between the SERVIR Water Africa-Arizona Team (SWAAT) and the SERVIR Program of NASA and USAID.

  15. Controls on Connectivity and Streamflow Generation in a Canadian Prairie Landscape

    NASA Astrophysics Data System (ADS)

    Brannen, R.; Spence, C.; Ireson, A. M.

    2013-12-01

    In the semi-arid, internally drained Prairie Pothole Region, the large volume of surface storage in depressional wetlands is a major factor in determining the extent and distribution of surface connections between wetlands. At catchment and sub-catchment scales, storage thresholds of different wetlands have been observed to control the connectivity of landscape components and the timing and degree of streamflow. We used a wide range of field observations in a 1 km2 sub-catchment in central Saskatchewan to analyze the surface and subsurface processes that contribute to or draw on basin storage, and how this controls the connectivity of stream networks and basin streamflow. It is well understood how surface water storage in depressions changes over time due to processes of snowmelt runoff, infiltration, and evapotranspiration. Missing is a quantification of the groundwater processes that may sustain surface storage in wetlands and prolong the receding limb of stream hydrographs. Although current models are capable of predicting many hydrological processes in this region, they do not integrate dynamic surface and subsurface processes that together influence the connectivity of headwater resources to downstream areas. In spring 2013, it was observed that surface storage capacity within wetland ponds mediated the streamflow response and occurrence of spills between wetlands, in accordance with the ';fill-spill' theory for prairie wetlands. The flux of shallow groundwater between pond and upland was negligible during snowmelt, as the water balance of ponds was dominated by the snowmelt signal from a larger than average winter snowpack. Gradual pond recession and sustained streamflow well into the summer season suggests that groundwater exchange may be a control on maintaining the water level of ponds above spill threshold.

  16. 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.

  17. Snowmelt Processes At High Altitude. How Does A Partly Frozen Ground Affect Alpine Aquifer During Snowmelt?

    NASA Astrophysics Data System (ADS)

    Bayard, D.; Stähli, M.; Turberg, P.; Parriaux, A.

    In alpine areas, the snow cover plays an important role as water reservoir, especially at high altitudes (over 2000 meters). Water is stored as snow over the winter and re- leased in spring, recharging mountain aquifers through infiltration. These aquifers are essential, especially for the supply of human activities with water during dry seasons. But these snow reservoirs may produce severe flooding, in particular when snowmelt is combined with heavy rainfall and a frozen underground. Surface frost can drastically reduce water infiltration by several orders of magnitude and therefore affect groundwater recharge. Evaluating the impact of frost on snowmelt runoff at selected sites in the Alps enables us to quantify water exportation processes (i.e. surface runoff, subsurface runoff and deep percolation) from the snow pack. The main objectives of this research project consisted (a) in studying the different pro- cesses influencing groundwater recharge during snowmelt periods, i.e. snow cover evolution, ground frost depth, snowmelt water runoff types on specific sites, (b) in as- sessing the variability of frost formation while taking into account spatial, altitudinal and climatic differences, (c) in identifying meteorological situations that are critical with respect to flooding. Two experimental sites were selected in the southern Swiss Alps, one at Hannigalp (2100 m) and the other at the Gd St-Bernard pass (2500 m). The Hannigalp site is characterized by a rather dry (600 mm/year) and wind free climate, whereas high amounts of precipitation (2100 mm/year) and strong winds are encountered at the Grand St Bernard. To investigate the delay in snowmelt due to the orientation and altitude, two secondary sites were additionally chosen near the Gd St-Bernard pass. In spite of a very thick snow pack, water balance measurements of winter 2000/01 showed for Grächen null to very low surface and subsurface flow due to the fact that soil frost was local. At the Gd St Bernard

  18. 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

  19. Effects of reservoir installation, San Juan-Chama Project water, and reservoir operations on streamflow and water quality in the Rio Chama and Rio Grande, northern and central New Mexico, 1938-2000

    USGS Publications Warehouse

    Langman, Jeff B.; Anderholm, Scott K.

    2004-01-01

    The coordinated operation of Heron, El Vado, and Abiquiu Dams on the Rio Chama and Cochiti Dam on the Rio Grande and the importation of Colorado River Basin water by the San Juan-Chama Project have altered streamflow and water quality of the Rio Chama and Rio Grande in northern and central New Mexico. The coordinated retention of streamflow in the four reservoirs increased median streamflows, decreased extreme flows, and decreased periods of small streamflow; inflow of San Juan-Chama Project water increased overall streamflow in the Rio Chama and Rio Grande. These changes to streamflow decreased specific conductance and suspended-sediment concentration and increased pH in the Rio Chama and the Rio Grande. Following construction of Heron and Cochiti Dams and integration of reservoir operations on the Rio Chama and the Rio Grande, the inflow of San Juan-Chama Project water and retention of snowmelt runoff influenced water quality. These influences varied by season because reservoir releases fluctuated according to downstream user needs and annual streamflow variation. The influences of San Juan-Chama Project water and retained snowmelt on water quality diminished with downstream flow as the Rio Grande was subjected to various natural and anthropogenic inflows. Because of the variability and type of seasonal influences, streamflow did not have a strong annual correlation with water quality in the Rio Chama or the Rio Grande.

  20. Trends in timing, magnitude, and duration of summer and fall/winter streamflows for unregulated coastal river basins in Maine during the 20th century

    USGS Publications Warehouse

    Dudley, Robert W.; Hodgkins, Glenn A.

    2005-01-01

    The U.S. Geological Survey (USGS), in cooperation with the Maine Atlantic Salmon Commission (ASC), began a study in 2003 to examine the timing, magnitude, and duration of summer (June through October) and fall/early winter (September through January) seasonal streamflows of unregulated coastal river basins in Maine and to correlate them to meteorological variables and winter/spring (January through May) seasonal streamflows. This study overlapped the summer seasonal window with the fall/early winter seasonal window to completely bracket the low-streamflow period during July, August, and September between periods of high streamflows in June and October. The ASC is concerned with the impacts of potentially changing meteorological and hydrologic conditions on Atlantic salmon survival. Because winter/spring high streamflows appear to have trended toward earlier dates over the 20th century in coastal Maine, it was hypothesized that the spring/summer recession to low streamflows could have a similar trend toward earlier, and possibly lower, longer lasting, late summer/early fall low streamflows during the 20th century. There were few statistically significant trends in the timing, magnitude, or duration of summer low streamflows for coastal river basins in Maine during the 20th century. The hypothesis that earlier winter/spring high streamflows may result in earlier or lower low streamflows is not supported by the data. No statistically significant trends in the magnitude of total runoff volume during the low-streamflow months of August and September were observed. The magnitude and timing of summer low streamflows correlated with the timing of fall/winter high streamflows and the amount of summer precipitation. The magnitude and timing of summer low streamflows did not correlate with the timing of spring snowmelt runoff. There were few correlations between the magnitude and timing of summer low streamflows and monthly mean surface air temperatures. There were few

  1. Post-settlement drivers of streamflow variability in the Canadian Prairies: an analysis of the effects of the Anthropocene

    NASA Astrophysics Data System (ADS)

    Nazemi, A.; Wheater, H. S.; Chun, K. P.; Bonsal, B. R.

    2014-12-01

    The Canadian Prairies are home to 75% of Canada's irrigated agriculture. This is supported by the historically reliable streamflow regime in the South Saskatchewan River (SSR), which is initiated from snowmelt on the eastern slopes of the Rocky Mountains. This streamflow regime, however, is facing various changes. Most obviously, post-settlement water resource management in the prairies has intensively regulated the timing and volume of natural streamflows. Moreover, the natural streamflow regime in the SSR exhibits large inter-annual variability, influenced by the phases of Pacific Decadal Oscillation (PDO). Finally, some other sources of climate variability have recently resulted in significant shifts in the timing and volume of the regional streamflow, associated with changes in the form and timing of precipitation as well as variations in annual snow accumulation and melt in headwater catchments. By considering five unregulated and three regulated streams, we formally diagnose the post-settlement drivers of variability in the SSR's streamflow regime using various statistical tests. Our results show that long-term variations in the SSR streamflow timing and volume can be described by complex interactions among the PDO, human regulation and non-PDO sources of climate variability. For instance, human regulation can intensify the variations in annual streamflow volume during extreme PDO conditions, and non-PDO sources of climate variability can be masked by the effects of PDO and/or human regulation. Changes in the annual streamflow timing can be linked to human regulation and non-PDO sources of climate variability; in particular, human regulation is the main driver of recent dependence between annual streamflow timing and volume. Our findings have major importance for water security assessment in the Canadian Prairies and contribute to better understanding of feedbacks in coupled Natural-Human water systems during the current Anthropocene.

  2. Trends and sensitivities of low streamflow extremes to discharge timing and magnitude in Pacific Northwest mountain streams

    NASA Astrophysics Data System (ADS)

    Kormos, Patrick R.; Luce, Charles H.; Wenger, Seth J.; Berghuijs, Wouter R.

    2016-07-01

    Path analyses of historical streamflow data from the Pacific Northwest indicate that the precipitation amount has been the dominant control on the magnitude of low streamflow extremes compared to the air temperature-affected timing of snowmelt runoff. The relative sensitivities of low streamflow to precipitation and temperature changes have important implications for adaptation planning because global circulation models produce relatively robust estimates of air temperature changes but have large uncertainties in projected precipitation amounts in the Pacific Northwest U.S. Quantile regression analyses indicate that low streamflow extremes from the majority of catchments in this study have declined from 1948 to 2013, which may significantly affect terrestrial and aquatic ecosystems, and water resource management. Trends in the 25th percentile of mean annual streamflow have declined and the center of timing has occurred earlier. We quantify the relative influences of total precipitation and air temperature on the annual low streamflow extremes from 42 stream gauges using mean annual streamflow as a proxy for precipitation amount effects and streamflow center of timing as a proxy for temperature effects on low flow metrics, including 7q10 summer (the minimum 7 day flow during summer with a 10 year return period), mean August, mean September, mean summer, 7q10 winter, and mean winter flow metrics. These methods have the benefit of using only readily available streamflow data, which makes our results robust against systematic errors in high elevation distributed precipitation data. Winter low flow metrics are weakly tied to both mean annual streamflow and center of timing.

  3. Earlier snowmelt reduces atmospheric carbon uptake in midlatitude subalpine forests

    NASA Astrophysics Data System (ADS)

    Winchell, Taylor S.; Barnard, David M.; Monson, Russell K.; Burns, Sean P.; Molotch, Noah P.

    2016-08-01

    Previous work demonstrates conflicting evidence regarding the influence of snowmelt timing on forest net ecosystem exchange (NEE). Based on 15 years of eddy covariance measurements in Colorado, years with earlier snowmelt exhibited less net carbon uptake during the snow ablation period, which is a period of high potential for productivity. Earlier snowmelt aligned with colder periods of the seasonal air temperature cycle relative to later snowmelt. We found that the colder ablation-period air temperatures during these early snowmelt years lead to reduced rates of daily NEE. Hence, earlier snowmelt associated with climate warming, counterintuitively, leads to colder atmospheric temperatures during the snow ablation period and concomitantly reduced rates of net carbon uptake. Using a multilinear-regression (R2 = 0.79, P < 0.001) relating snow ablation period mean air temperature and peak snow water equivalent (SWE) to ablation-period NEE, we predict that earlier snowmelt and decreased SWE may cause a 45% reduction in midcentury ablation-period net carbon uptake.

  4. Spatio-temporal variability of snowmelt and runoff generation during rain-on-snow events in a forested mountain environment

    NASA Astrophysics Data System (ADS)

    Garvelmann, Jakob; Pohl, Stefan; Weiler, Markus

    2014-05-01

    A network consisting of 81 standalone snow monitoring stations (SnoMoS), precipitation measurements, and streamflow data was used to analyze the observed snowcover distribution and melt dynamics during mid-winter rain-on-snow (ROS) events generating flooding in three study catchments with differing elevations, topographic characteristics, and areal extent in the Black Forest region of south-western Germany. The crucial importance of the initial snowcover distribution prior to the event became evident. The contribution of snowmelt to total runoff was on average about 60%, highlighting the significance of snowmelt for the flood generation during ROS. The catchment with the most distinct topography was selected to further investigate the drivers of the spatio-temporal variability of snowmelt and the water available for stormflow runoff. A multiple linear regression analysis using elevation, aspect, and land cover as predictors for the SWE distribution within the catchment was applied on an hourly time-step using the observed dynamic at the SnoMoS locations. Based on this analysis the spatial distribution of the initial snowcover and the snowmelt occurring in different parts of the study basin during two ROS events in December 2012 was calculated. The amount and the spatial distribution of water potentially being available for the generation of runoff at the interface between the snowpack and the surface below was calculated considering spatially variable melt rates, water retention capacity of the snow cover and the input of liquid precipitation. Elevation was found to be the most important terrain feature having the biggest influence on the water release from the snowpack. Even though the highest total amounts of water from precipitation and snowmelt were potentially available for runoff in the higher elevations, the snowpack released reduced amounts of water to runoff in these regions. South-facing terrain contributed more to runoff than north facing slopes and more

  5. Seasonal and spatial patterns in diurnal cycles in streamflow in the western United States

    USGS Publications Warehouse

    Lundquist, J.D.; Cayan, D.R.

    2002-01-01

    The diurnal cycle in streamflow constitutes a significant part of the variability in many rivers in the western United States and can be used to understand some of the dominant processes affecting the water balance of a given river basin. Rivers in which water is added diurnally, as in snowmelt, and rivers in which water is removed diurnally, as in evapotranspiration and infiltration, exhibit substantial differences in the timing, relative magnitude, and shape of their diurnal flow variations. Snowmelt-dominated rivers achieve their highest sustained flow and largest diurnal fluctuations during the spring melt season. These fluctuations are characterized by sharp rises and gradual declines in discharge each day. In large snowmelt-dominated basins, at the end of the melt season, the hour of maximum discharge shifts to later in the day as the snow line retreats to higher elevations. Many evapotranspiration/infiltration-dominated rivers in the western states achieve their highest sustained flows during the winter rainy season but exhibit their strongest diurnal cycles during summer months, when discharge is low, and the diurnal fluctuations compose a large percentage of the total flow. In contrast to snowmelt-dominated rivers, the maximum discharge in evapotranspiration/infiltration-dominated rivers occurs consistently in the morning throughout the summer. In these rivers, diurnal changes are characterized by a gradual rise and sharp decline each day.

  6. Sensitivity of Alpine Snow and Streamflow Regimes to Climate Changes

    NASA Astrophysics Data System (ADS)

    Rasouli, K.; Pomeroy, J. W.; Marks, D. G.; Bernhardt, M.

    2014-12-01

    Understanding the sensitivity of hydrological processes to climate change in alpine areas with snow dominated regimes is of paramount importance as alpine basins show both high runoff efficiency associated with the melt of the seasonal snowpack and great sensitivity of snow processes to temperature change. In this study, meteorological data measured in a selection of alpine headwaters basins including Reynolds Mountain East, Idaho, USA, Wolf Creek, Yukon in Canada, and Zugspitze Mountain, Germany with climates ranging from arctic to continental temperate were used to study the snow and streamflow sensitivity to climate change. All research sites have detailed multi-decadal meteorological and snow measurements. The Cold Regions Hydrological Modelling platform (CRHM) was used to create a model representing a typical alpine headwater basin discretized into hydrological response units with physically based representations of snow redistribution by wind, complex terrain snowmelt energetics and runoff processes in alpine tundra. The sensitivity of snow hydrology to climate change was investigated by changing air temperature and precipitation using weather generating methods based on the change factors obtained from different climate model projections for future and current periods. The basin mean and spatial variability of peak snow water equivalent, sublimation loss, duration of snow season, snowmelt rates, streamflow peak, and basin discharge were assessed under varying climate scenarios and the most sensitive hydrological mechanisms to the changes in the different alpine climates were detected. The results show that snow hydrology in colder alpine climates is more resilient to warming than that in warmer climates, but that compensatory factors to warming such as reduced blowing snow sublimation loss and reduced melt rate should also be assessed when considering climate change impacts on alpine hydrology.

  7. Potential impacts of climate warming on runoff from snowmelt: a case study of two mountainous basins in the Upper Rio Grande

    NASA Astrophysics Data System (ADS)

    Rango, A.; Steele, C. M.; Elias, E.; Mejia, J.; Fernald, A.

    2013-12-01

    We used historical climate, snow cover and streamflow data in the Snowmelt Runoff Model (SRM) to drive simulations of runoff from two mountainous basins in the Upper Rio Grande. The basins selected for this study are El Rito and Santa Fe. With climate warming, both have been shown to be at risk of losing annual snowpack and the associated peak in the spring hydrograph caused by snowmelt. Historical flow simulations supplied model parameters specific to each basin (runoff coefficients, degree day factors, temperature lapse rates, critical temperature and recession coefficients). These parameters were then used in applying SRM under changed climate conditions (scenario A2, ECHAM-5 general circulation model, 2046-2100). Although there is some interannual variability, under the A2 scenario the SRM simulations imply (i) a profound loss of annual snowpack at all but the highest elevations; (ii) decline in springtime streamflow (fraction of flow occurring between April and July) and (iii) earlier occurrence of winter-spring center of volume (half total runoff volume for January 1 to May 31). Our results have profound implications for the rural acequia community in El Rito for whom the annual snowpack acts as a natural reservoir releasing water to the acequias (irrigation canals) concurrent with the beginning of the growing season. In El Rito, the only alternative to water from snowmelt runoff is groundwater, but this source of water will also be affected by the accumulation, quantity and duration of annual snowpack. With two reservoirs, the urban area of Santa Fe is less dependent on the timing of snowmelt than El Rito. Additionally, Santa Fe has access to alternate sources of surface water (e.g., from the San Juan-Chama Project). Nevertheless, climate-change induced scarcity of water throughout the region will also have important socio-economic and political impacts on the City of Santa Fe.

  8. Insights into streamflow generation mechanisms using high-frequency analysis of isotopes and water quality in streamflow and precipitation

    NASA Astrophysics Data System (ADS)

    von Freyberg, Jana; Kirchner, James W.

    2017-04-01

    In the pre-Alpine Alptal catchment in central Switzerland, snowmelt and rainfall events cause rapid changes not only in hydrological conditions, but also in water quality. A flood forecasting model for such a mountainous catchment thus requires process understanding that is informed by high-frequency monitoring of hydrological and hydrochemical parameters. Therefore, we installed a high-frequency sampling and analysis system near the outlet of the 0.7 km2 Erlenbach catchment, a headwater tributary of the Alp river. We measured stable water isotopes (δ18O, δ2H) in precipitation and streamwater using Picarro, Inc.'s (Santa Clara, CA, USA) newly developed Continuous Water Sampler Module (CWS) coupled to their L2130-i Cavity Ring-Down Spectrometer, at 30 min temporal resolution. Water quality was monitored with a dual-channel ion chomatograph (Metrohm AG, Herisau, Switzerland) for analysis of major cations and anions, as well as with a UV-Vis spectroscopy system and electrochemical probes (s::can Messtechnik GmbH, Vienna, Austria) for characterization of nutrients and basic water quality parameters. For quantification of trace elements and metals, we collected additional water samples for subsequent ICP-MS analysis in the laboratory. To illustrate the applicability of our newly developed automated analysis and sampling system under field conditions, we will present initial results from the 2016 fall and winter seasons at the Erlenbach catchment. During this period, river discharge was mainly fed by groundwater, as well as intermittent snowmelt and rain-on-snow events. Our high-frequency data set, along with spatially distributed sampling of snowmelt, enables a detailed analysis of source areas, flow pathways and biogeochemical processes that control chemical dynamics in streamflow and the discharge regime.

  9. Has global warming changed timing of winter-spring streamflows over North America?

    NASA Astrophysics Data System (ADS)

    Kam, J.; Knutson, T. R.; Milly, P. C. D.

    2015-12-01

    Wherever snowmelt runoff substantially contributes to winter-spring streamflows, warmer winter-spring temperature can accelerate snow melt and reduce later streamflows. These changes can adversely affect human activities and ecological communities (e.g. flood, drought, salmon survival rate, and blooming season). Here we investigate changes in timing of winter-spring streamflows over North America (NA) during 1933-2013 and 1951-2000 using observed streamflow and simulated runoff from pre-industrial (unforced) control and historical (realistically forced) runs from the Geophysical Fluid Dynamics Laboratory Climate Model version 3. The study regions are north of 41˚N in NA. We analyze winter-spring center of volume date (WSCV), the date by which half of the accumulated January through June daily streamflow volume occurs. We first performed a sliding trend analysis of WSCV for time periods starting in various years (1951 through 1984) and ending in 2000. We found that the observed decreasing trends (Theil-Sen slopes) of WSCV over the northeast and northwest U.S. regions are at the edge of detectability (i.e., lie near the edge of the 5th-95th percentile envelope of control runs) for trends beginning any time between 1950 and 1970, but are consistent with the envelope of historical runs for all beginning trend years. Interestingly, for the 1933-2013 analysis, results for the northwest U.S. show that the observed trends of WSCV are positive for periods beginning as early as the mid-1960s, and inconsistent with historical runs for periods beginning in the mid-1950s and later. Aside from this inconsistency, observed trends to 2013 are consistent with both control and historical runs. This study suggests that internal variability has played a major role in timing of winter-spring streamflows to date, despite global warming, and thus that clear detection and attribution of WSCV trends in the study regions may require longer streamflow records than those now available.

  10. United States streamflow probabilities based on forecasted La Nina, winter-spring 2000

    USGS Publications Warehouse

    Dettinger, M.D.; Cayan, D.R.; Redmond, K.T.

    1999-01-01

    Although for the last 5 months the TahitiDarwin Southern Oscillation Index (SOI) has hovered close to normal, the “equatorial” SOI has remained in the La Niña category and predictions are calling for La Niña conditions this winter. In view of these predictions of continuing La Niña and as a direct extension of previous studies of the relations between El NiñoSouthern Oscil-lation (ENSO) conditions and streamflow in the United States (e.g., Redmond and Koch, 1991; Cayan and Webb, 1992; Redmond and Cayan, 1994; Dettinger et al., 1998; Garen, 1998; Cayan et al., 1999; Dettinger et al., in press), the probabilities that United States streamflows from December 1999 through July 2000 will be in upper and lower thirds (terciles) of the historical records are estimated here. The processes that link ENSO to North American streamflow are discussed in detail in these diagnostics studies. Our justification for generating this forecast is threefold: (1) Cayan et al. (1999) recently have shown that ENSO influences on streamflow variations and extremes are proportionately larger than the corresponding precipitation teleconnections. (2) Redmond and Cayan (1994) and Dettinger et al. (in press) also have shown that the low-frequency evolution of ENSO conditions support long-lead correlations between ENSO and streamflow in many rivers of the conterminous United States. (3) In many rivers, significant (weeks-to-months) delays between precipitation and the release to streams of snowmelt or ground-water discharge can support even longer term forecasts of streamflow than is possible for precipitation. The relatively slow, orderly evolution of El Niño-Southern Oscillation episodes, the accentuated dependence of streamflow upon ENSO, and the long lags between precipitation and flow encourage us to provide the following analysis as a simple prediction of this year’s river flows.

  11. Klamath Falls downtown development geothermal sidewalk snowmelt

    SciTech Connect

    Brown, B.

    1995-10-01

    The Klamuth Falls, Oregon, downtown has seen a period of decline over the past 20 years as businesses have moved to new suburban shopping centers. Downtown business owners and the Klamuth Falls Downtown Redevelopment Agency are working to reverse that trend with a Downtown Streetscape Project intended to make the downtown a more pleasant place to work and do business. The visible elements of the project include new crosswalks with brick pavers, wheelchair ramps at sidewalk corners, new concrete sidewalks with a consistent decorative grid pattern, sidewalk planters for trees and flowers, and antique-style park benches and lighting fixtures. A less visible, but equally valuable feature of the project is the plastic tubing installed under the sidewalks, wheelchair ramps and crosswalks, designed to keep them snow and ice free in the winter. A unique feature of the snowmelt system is the use of geothermal heated water on the return side of the Klamath Falls Geothermal District Heating System, made possible by the recent expansion of the district heating system.

  12. Evaluation of Snow Cover Depletion to Support Snowmelt Runoff Prediction for the Cache la Poudre River, Colorado

    NASA Astrophysics Data System (ADS)

    Richer, E. E.; Kampf, S. K.; Fassnacht, S. R.

    2008-12-01

    The Cache la Poudre River in northeastern Colorado is a source of water for many agricultural, municipal, and industrial users. Most runoff in the basin is generated from snowmelt, but snow measurements are sparse, located only at a few high elevation SNOTEL stations and snow courses. Over much of the watershed, no snow measurements are available to support runoff forecasts. For this study we analyzed snow covered area (SCA) depletion characteristics to evaluate whether SCA data could improve snowmelt runoff prediction. Moderate Resolution Imaging Spectroradiometer (MODIS) 8-day snow-cover products were obtained for the Cache la Poudre basin from 2000 to 2006 for March through June of each year. We analyzed snow cover depletion characteristics for spatial subsets of the basin, including sub-basins and elevation bands. Regression analyses compare the 8-day SCA images to 8-day average stream flow at the USGS canyon mouth gauge (the forecasting location). Results from regression analyses show a wide range of relationships between SCA and streamflow (0.032<0.92), mostly as a result of high inter- annual variability in the flow regime. SCA image impairment from cloud cover was generally low but did impact results in some years. For sub-basins, the strongest correlations between SCA and streamflow were for high elevation sub-basins (0.602<0.92), whereas for elevation bands, the strongest correlations were for a mid-elevation band, 2680-3042 m (0.602<0.92). The poorest relationships between SCA and streamflow occurred for low elevation bands, 1591-1953 m and 1954-2315 m, and very high elevation bands, 3406-3768 m and 3769-4131 m. The strong relationship between SCA and discharge at middle elevations suggests that runoff prediction can be improved by monitoring snow cover within these areas. The initial rise in the snowmelt hydrograph correlates well with SCA depletion at middle elevations, whereas the onset of peak flow does not occur until a significant change in snow

  13. Recent tree die-off has little effect on streamflow in contrast to expected increases from historical studies

    NASA Astrophysics Data System (ADS)

    Biederman, Joel A.; Somor, Andrew J.; Harpold, Adrian A.; Gutmann, Ethan D.; Breshears, David D.; Troch, Peter A.; Gochis, David J.; Scott, Russell L.; Meddens, Arjan J. H.; Brooks, Paul D.

    2015-12-01

    Recent bark beetle epidemics have caused regional-scale tree mortality in many snowmelt-dominated headwater catchments of western North America. Initial expectations of increased streamflow have not been supported by observations, and the basin-scale response of annual streamflow is largely unknown. Here we quantified annual streamflow responses during the decade following tree die-off in eight infested catchments in the Colorado River headwaters and one nearby control catchment. We employed three alternative empirical methods: (i) double-mass comparison between impacted and control catchments, (ii) runoff ratio comparison before and after die-off, and (iii) time-trend analysis using climate-driven linear models. In contrast to streamflow increases predicted by historical paired catchment studies and recent modeling, we did not detect streamflow changes in most basins following die-off, while one basin consistently showed decreased streamflow. The three analysis methods produced generally consistent results, with time-trend analysis showing precipitation was the strongest predictor of streamflow variability (R2 = 74-96%). Time-trend analysis revealed post-die-off streamflow decreased in three catchments by 11-29%, with no change in the other five catchments. Although counter to initial expectations, these results are consistent with increased transpiration by surviving vegetation and the growing body of literature documenting increased snow sublimation and evaporation from the subcanopy following die-off in water-limited, snow-dominated forests. The observations presented here challenge the widespread expectation that streamflow will increase following beetle-induced forest die-off and highlight the need to better understand the processes driving hydrologic response to forest disturbance.

  14. Snowmelt Runoff: A New Focus of Urban Nonpoint Source Pollution

    PubMed Central

    Zhu, Hui; Xu, Yingying; Yan, Baixing; Guan, Jiunian

    2012-01-01

    Irregular precipitation associated with global climate change had been causing various problems in urban regions. Besides the runoff due to rainfall in summer, the snowmelt runoff in early spring could also play an important role in deteriorating the water quality of the receiving waters. Due to global climate change, the snowfall has increased gradually in individual regions, and snowstorms occur more frequently, which leads to an enhancement of snowmelt runoff flow during the melting seasons. What is more, rivers just awaking from freezing cosntitute a frail ecosystem, with poor self-purification capacity, however, the urban snowmelt runoff could carry diverse pollutants accumulated during the winter, such as coal and/or gas combustion products, snowmelting agents, automotive exhaust and so on, which seriously threaten the receiving water quality. Nevertheless, most of the research focused on the rainfall runoff in rainy seasons, and the study on snowmelt runoff is still a neglected field in many countries and regions. In conclusion, due to the considerable water quantity and the worrisome water quality, snowmelt runoff in urban regions with large impervious surface areas should be listed among the important targets in urban nonpoint source pollution management and control. PMID:23202881

  15. A new method of snowmelt sampling for water stable isotopes

    USGS Publications Warehouse

    Penna, D.; Ahmad, M.; Birks, S. J.; Bouchaou, L.; Brencic, M.; Butt, S.; Holko, L.; Jeelani, G.; Martinez, D. E.; Melikadze, G.; Shanley, J.B.; Sokratov, S. A.; Stadnyk, T.; Sugimoto, A.; Vreca, P.

    2014-01-01

    We modified a passive capillary sampler (PCS) to collect snowmelt water for isotopic analysis. Past applications of PCSs have been to sample soil water, but the novel aspect of this study was the placement of the PCSs at the ground-snowpack interface to collect snowmelt. We deployed arrays of PCSs at 11 sites in ten partner countries on five continents representing a range of climate and snow cover worldwide. The PCS reliably collected snowmelt at all sites and caused negligible evaporative fractionation effects in the samples. PCS is low-cost, easy to install, and collects a representative integrated snowmelt sample throughout the melt season or at the melt event scale. Unlike snow cores, the PCS collects the water that would actually infiltrate the soil; thus, its isotopic composition is appropriate to use for tracing snowmelt water through the hydrologic cycle. The purpose of this Briefing is to show the potential advantages of PCSs and recommend guidelines for constructing and installing them based on our preliminary results from two snowmelt seasons.

  16. Snowmelt runoff: a new focus of urban nonpoint source pollution.

    PubMed

    Zhu, Hui; Xu, Yingying; Yan, Baixing; Guan, Jiunian

    2012-11-30

    Irregular precipitation associated with global climate change had been causing various problems in urban regions. Besides the runoff due to rainfall in summer, the snowmelt runoff in early spring could also play an important role in deteriorating the water quality of the receiving waters. Due to global climate change, the snowfall has increased gradually in individual regions, and snowstorms occur more frequently, which leads to an enhancement of snowmelt runoff flow during the melting seasons. What is more, rivers just awaking from freezing constitute a frail ecosystem, with poor self-purification capacity, however, the urban snowmelt runoff could carry diverse pollutants accumulated during the winter, such as coal and/or gas combustion products, snowmelting agents, automotive exhaust and so on, which seriously threaten the receiving water quality. Nevertheless, most of the research focused on the rainfall runoff in rainy seasons, and the study on snowmelt runoff is still a neglected field in many countries and regions. In conclusion, due to the considerable water quantity and the worrisome water quality, snowmelt runoff in urban regions with large impervious surface areas should be listed among the important targets in urban nonpoint source pollution management and control.

  17. An assessment of streamflow vulnerability to climate using ...

    EPA Pesticide Factsheets

    Identifying regions with similar hydrology is useful for assessing water quality and quantity across the U.S., especially areas that are difficult or costly to monitor. For example, hydrologic landscapes (HLs) have been used to map streamflow variability and assess the spatial distribution of climatic response in Oregon, Alaska, and the Pacific Northwest. HLs have also been applied to assess historic and projected climatic impacts across the Western U.S. In this project, we summarized (1) the HL classification methodology and (2) the utility of using HLs as a tool to classify the vulnerability of streams to climatic changes in the Western U.S. During the HL classification process, we analyzed climate, seasonality, aquifer permeability, terrain, and soil permeability as the primary hydrologic drivers (and precipitation intensity as a secondary driver) associated with large scale hydrologic processes (storage, conveyance, and flow of water into or out of the watershed) in the West. We derived the dominant hydrologic pathways (surface runoff or deep or shallow groundwater) from the HL classification of different catchments to test our hypotheses: 1) Changes in climate will have greater impacts on streamflow in catchments dominated by surface runoff. 2) Catchments historically fed by surface runoff from winter snowmelt in the spring will experience greater impact if precipitation falls as rain instead of snow. We calculated S* (precipitation surplus, which includes

  18. An assessment of streamflow vulnerability to climate using ...

    EPA Pesticide Factsheets

    Identifying regions with similar hydrology is useful for assessing water quality and quantity across the U.S., especially areas that are difficult or costly to monitor. For example, hydrologic landscapes (HLs) have been used to map streamflow variability and assess the spatial distribution of climatic response in Oregon, Alaska, and the Pacific Northwest. HLs have also been applied to assess historic and projected climatic impacts across the Western U.S. In this project, we summarized (1) the HL classification methodology and (2) the utility of using HLs as a tool to classify the vulnerability of streams to climatic changes in the Western U.S. During the HL classification process, we analyzed climate, seasonality, aquifer permeability, terrain, and soil permeability as the primary hydrologic drivers (and precipitation intensity as a secondary driver) associated with large scale hydrologic processes (storage, conveyance, and flow of water into or out of the watershed) in the West. We derived the dominant hydrologic pathways (surface runoff or deep or shallow groundwater) from the HL classification of different catchments to test our hypotheses: 1) Changes in climate will have greater impacts on streamflow in catchments dominated by surface runoff. 2) Catchments historically fed by surface runoff from winter snowmelt in the spring will experience greater impact if precipitation falls as rain instead of snow. We calculated S* (precipitation surplus, which includes

  19. Winter streamflow analysis in frozen, alpine catchments to quantify groundwater contribution and properties

    NASA Astrophysics Data System (ADS)

    Stoelzle, Michael; Weiler, Markus

    2016-04-01

    Alpine catchments are often considered as quickly responding systems where streamflow contributions from subsurface storages (groundwater) are mostly negligible due to the steep topography, low permeable bedrock and the absence of well-developed soils. Many studies in high altitude catchments have hence focused on water stored in snowpack and glaciers or on rainfall-runoff processes as the dominant streamflow contributions. Interestingly less effort has been devoted to winter streamflow analysis when melt- or rainfall-driven contributions are switched off due to the frozen state of the catchment. Considering projected changes in the alpine cryosphere (e.g. snow, glacier, permafrost) quantification of groundwater storage and contribution to streamflow is crucial to assess the social and ecological implications for downstream areas (e.g. water temperature, drought propagation). In this study we hypothesize that groundwater is the main streamflow contribution during winter and thus being responsible for the perennial regime of many alpine catchments. The hypothesis is investigated with well-known methods based on recession and breakpoint analysis of the streamflow regimes and temperature data to determine frozen periods. Analyzing nine catchments in Switzerland with mean elevation between 1000 and 2400 m asl, we found that above a mean elevation of 1800 m asl winter recessions are sufficient long and persistent enough to quantify groundwater contribution to streamflow and to characterize the properties of subsurface storage. The results show that groundwater in alpine catchment is the dominant streamflow contribution for nearly half a year and accountable for several hundred millimeter of annual streamflow. In sub-alpine catchments, driven by a mix of snowmelt and rainfall, a clear quantification of groundwater contributions is rather challenging due to discontinuous frozen periods in winter. We found that the inter-annual variability of different streamflow

  20. A spatially distributed energy balance snowmelt model for application in mountain basins

    USGS Publications Warehouse

    Marks, D.; Domingo, J.; Susong, D.; Link, T.; Garen, D.

    1999-01-01

    Snowmelt is the principal source for soil moisture, ground-water re-charge, and stream-flow in mountainous regions of the western US, Canada, and other similar regions of the world. Information on the timing, magnitude, and contributing area of melt under variable or changing climate conditions is required for successful water and resource management. A coupled energy and mass-balance model ISNOBAL is used to simulate the development and melting of the seasonal snowcover in several mountain basins in California, Idaho, and Utah. Simulations are done over basins varying from 1 to 2500 km2, with simulation periods varying from a few days for the smallest basin, Emerald Lake watershed in California, to multiple snow seasons for the Park City area in Utah. The model is driven by topographically corrected estimates of radiation, temperature, humidity, wind, and precipitation. Simulation results in all basins closely match independently measured snow water equivalent, snow depth, or runoff during both the development and depletion of the snowcover. Spatially distributed estimates of snow deposition and melt allow us to better understand the interaction between topographic structure, climate, and moisture availability in mountain basins of the western US. Application of topographically distributed models such as this will lead to improved water resource and watershed management.Snowmelt is the principal source for soil moisture, ground-water re-charge, and stream-flow in mountainous regions of the western US, Canada, and other similar regions of the world. Information on the timing, magnitude, and contributing area of melt under variable or changing climate conditions is required for successful water and resource management. A coupled energy and mass-balance model ISNOBAL is used to simulate the development and melting of the seasonal snowcover in several mountain basins in California, Idaho, and Utah. Simulations are done over basins varying from 1 to 2500 km2, with

  1. Effect of reforestation on streamflow in central New York

    USGS Publications Warehouse

    Schneider, William Joseph; Ayer, Gordon Roundy

    1961-01-01

    interception and transpiration in the reforested areas. The reductions in peak discharges during the dormant period are attributed largely to increased interception and sublimation of snowfall, and a gradual desynchronization of snowmelt runoff from the wooded and open areas of partly reforested watersheds. The changes in streamflow occurred gradually over the years; it could not be determined from the data whether changes in streamflow were still occurring in 1958, or whether they had reached a maximum.

  2. Shifts in historical streamflow extremes in the Colorado River Basin

    DOE PAGES

    Solander, Kurt C.; Bennett, Katrina Eleanor; Middleton, Richard Stephen

    2017-07-10

    The global phenomenon of climate change-induced shifts in precipitation leading to "wet regions getting wetter" and "dry regions getting drier" has been widely studied. However, the propagation of these changes in atmospheric moisture within stream channels is not a direct relationship due to differences in the timing of how changing precipitation patterns interact with various land surfaces. Streamflow is of particular interest in the Colorado River Basin (CRB) due to the region’s rapidly growing population, projected temperature increases that are expected to be higher than elsewhere in the contiguous United States, and subsequent climate-driven disturbances including drought, vegetation mortality, andmore » wildfire, which makes the region more vulnerable to changes in hydrologic extremes. Here in this study, we determine how streamflow extremes have shifted in the CRB using two statistical methods—the Mann-Kendall trend detection analysis and Generalized Extreme Value (GEV) theorem. We evaluate these changes in the context of key flow metrics that include high and low flow percentiles, maximum and minimum 7-day flows, and the center timing of streamflow using historical gage records representative of natural flows. Monthly results indicate declines of up to 41% for high and low flows during the June to July peak runoff season, while increases of up to 24% were observed earlier from March to April. Finally, our results highlight a key threshold elevation and latitude of 2300 m and 39° North, respectively, where there is a distinct shift in the trend. The spatiotemporal patterns observed are indicative of changing snowmelt patterns as a primary cause of the shifts. Identification of how this change varies spatially has consequences for improved land management strategies, as specific regions most vulnerable to threats can be prioritized for mitigation or adaptation as the climate warms.« less

  3. Increased spring freezing vulnerability for alpine shrubs under early snowmelt.

    PubMed

    Wheeler, J A; Hoch, G; Cortés, A J; Sedlacek, J; Wipf, S; Rixen, C

    2014-05-01

    Alpine dwarf shrub communities are phenologically linked with snowmelt timing, so early spring exposure may increase risk of freezing damage during early development, and consequently reduce seasonal growth. We examined whether environmental factors (duration of snow cover, elevation) influenced size and the vulnerability of shrubs to spring freezing along elevational gradients and snow microhabitats by modelling the past frequency of spring freezing events. We sampled biomass and measured the size of Salix herbacea, Vaccinium myrtillus, Vaccinium uliginosum and Loiseleuria procumbens in late spring. Leaves were exposed to freezing temperatures to determine the temperature at which 50% of specimens are killed for each species and sampling site. By linking site snowmelt and temperatures to long-term climate measurements, we extrapolated the frequency of spring freezing events at each elevation, snow microhabitat and per species over 37 years. Snowmelt timing was significantly driven by microhabitat effects, but was independent of elevation. Shrub growth was neither enhanced nor reduced by earlier snowmelt, but decreased with elevation. Freezing resistance was strongly species dependent, and did not differ along the elevation or snowmelt gradient. Microclimate extrapolation suggested that potentially lethal freezing events (in May and June) occurred for three of the four species examined. Freezing events never occurred on late snow beds, and increased in frequency with earlier snowmelt and higher elevation. Extrapolated freezing events showed a slight, non-significant increase over the 37-year record. We suggest that earlier snowmelt does not enhance growth in four dominant alpine shrubs, but increases the risk of lethal spring freezing exposure for less freezing-resistant species.

  4. Controls on Snowmelt Partitioning to Surface and Groundwater Flow

    NASA Astrophysics Data System (ADS)

    Hill, A. F.; Williams, M. W.; Chowanski, K.

    2015-12-01

    High altitude mountainous regions are vital source areas of water and their snow-dominated hydrologic processes are particularly sensitive to climate change. Yet, basic questions remain about snowmelt's partitioning between surface and subsurface flow and the role it plays in replenishing alpine groundwater. High geologic heterogeneity in mountain regions and inter-annual climate variation challenge our ability to address these questions and anticipate related water resource vulnerabilities. This study compares bedrock and colluvial aquifer system responses to snowmelt on Niwot Ridge in Colorado over five years (2008-2012) to evaluate the role of snowmelt in annual groundwater recharge over varying temporal and spatial scales. We monitor water tables and conservative tracers in source water samples to infer groundwater interaction with snow melt based on unique signatures of source waters. We find that snowmelt is the most important hydrologic alpine groundwater recharge event with water table rises of up to 8m and 4m in response to the freshet in the bedrock and colluvial aquifers, respectively. However, the nature of groundwater response not only depends on climate conditions and the geologic setting, but also on wind scour and topography that affect seasonally frozen soil extent and thus soil infiltration capacity during snowmelt. Areas with high scour and small overlying snow experience smaller annual water table rise and recharge comes from a mix of snowmelt and summer rain sources. This finding suggests that localized recharge processes where seasonally frozen soil is present may not be as vulnerable to declining snowpacks as aquifers more exclusively reliant on snowmelt for recharge. Because wind scour indices can be determined using remotely sensed information, it is possible to anticipate this groundwater response over large scales and in remote regions.

  5. Links between large-scale circulation patterns and streamflow in Central Europe: A review

    NASA Astrophysics Data System (ADS)

    Steirou, Eva; Gerlitz, Lars; Apel, Heiko; Merz, Bruno

    2017-06-01

    We disentangle the relationships between streamflow and large-scale atmospheric circulation in Central Europe (CE), an area affected by climatic influences from different origins (Atlantic, Mediterranean and Continental) and characterized by diverse topography and flow regimes. Our literature review examines in detail the links between mean, high and low flows in CE and large-scale circulation patterns, with focus on two closely related phenomena, the North Atlantic Oscillation (NAO) and the Western-zonal circulation (WC). For both patterns, significant relations, consistent between different studies, are found for large parts of CE. The strongest links are found for the winter season, forming a dipole-like pattern with positive relationships with streamflow north of the Alps and the Carpathians for both indices and negative relationships for the NAO in the south. An influence of winter NAO is also detected in the amplitude and timing of snowmelt flows later in the year. Discharge in CE has further been linked to other large-scale climatic modes such as the Scandinavia pattern (SCA), the East Atlantic/West Russian pattern (EA/WR), the El Niño-Southern Oscillation (ENSO) and synoptic weather patterns such as the Vb weather regime. Different mechanisms suggested in the literature to modulate links between streamflow and the NAO are combined with topographical characteristics of the target area in order to explain the divergent NAO/WC influence on streamflow in different parts of CE. In particular, a precipitation mechanism seems to regulate winter flows in North-Western Germany, an area with short duration of snow cover and with rainfall-generated floods. The precipitation mechanism is also likely in Southern CE, where correlations between the NAO and temperature are low. Finally, in the rest of the study area (Northern CE, Alpine region), a joint precipitation-snow mechanism influences floods not only in winter, but also in the spring/snowmelt period, providing

  6. Nonparametric Streamflow Disaggregation Model

    NASA Astrophysics Data System (ADS)

    Lee, T.; Salas, J. D.; Prairie, J. R.

    2009-05-01

    Stochastic streamflow generation is generally utilized for planning and management of water resources systems. For this purpose a number of parametric and nonparametric modeling alternatives have been suggested in literature. Among them temporal and spatial disaggregation approaches play an important role particularly to make sure that historical variance-covariance properties are preserved at various temporal and spatial scales. In this paper, we review the underlying features of nonparametric disaggregation, identify some of their pros and cons, and propose a disaggregation algorithm that is capable of surmounting some of the shortcoming of the current models. The proposed models hinge on k-nearest neighbor resampling, the accurate adjusting procedure, and a genetic algorithm. The model has been tested and compared to an existing nonparametric disaggregation approach using data of the Colorado River system. It has been shown that the model is capable of (i) reproducing the season-to-season correlations including the correlation between the last season of the previous year and the first season of the current year, (ii) minimizing or avoiding the generation of flow patterns across the year that are literally the same as those of the historical records, and (iii) minimizing or avoiding the generation of negative flows. In addition, it is applicable to intermittent river regimes. Suggestions for further improving the model are discussed.

  7. Streamflow changes in the Sierra Nevada, California, simulated using a statistically downscaled general circulation model scenario of climate change

    USGS Publications Warehouse

    Wilby, Robert L.; Dettinger, Michael D.

    2000-01-01

    Simulations of future climate using general circulation models (GCMs) suggest that rising concentrations of greenhouse gases may have significant consequences for the global climate. Of less certainty is the extent to which regional scale (i.e., sub-GCM grid) environmental processes will be affected. In this chapter, a range of downscaling techniques are critiqued. Then a relatively simple (yet robust) statistical downscaling technique and its use in the modelling of future runoff scenarios for three river basins in the Sierra Nevada, California, is described. This region was selected because GCM experiments driven by combined greenhouse-gas and sulphate-aerosol forcings consistently show major changes in the hydro-climate of the southwest United States by the end of the 21st century. The regression-based downscaling method was used to simulate daily rainfall and temperature series for streamflow modelling in three Californian river basins under current-and future-climate conditions. The downscaling involved just three predictor variables (specific humidity, zonal velocity component of airflow, and 500 hPa geopotential heights) supplied by the U.K. Meteorological Office couple ocean-atmosphere model (HadCM2) for the grid point nearest the target basins. When evaluated using independent data, the model showed reasonable skill at reproducing observed area-average precipitation, temperature, and concomitant streamflow variations. Overall, the downscaled data resulted in slight underestimates of mean annual streamflow due to underestimates of precipitation in spring and positive temperature biases in winter. Differences in the skill of simulated streamflows amongst the three basins were attributed to the smoothing effects of snowpack on streamflow responses to climate forcing. The Merced and American River basins drain the western, windward slope of the Sierra Nevada and are snowmelt dominated, whereas the Carson River drains the eastern, leeward slope and is a mix of

  8. A streamflow assimilation system for ensemble streamflow forecast over France

    NASA Astrophysics Data System (ADS)

    Thirel, G.; Martin, E.; Mahfouf, J. F.; Massart, S.; Ricci, S.; Habets, F.

    2009-04-01

    SAFRAN-ISBA-MODCOU (SIM) is a hydro-meteorological model used at Météo-France to predict soil water content and river streamflows. In order to produce a better initial state for the Ensemble Streamflow forecasts, an assimilation system is developed at Météo-France. This system uses past streamflow measurements in order to assess the best initial state of soil water content of the model for streamflow prediction. The data assimilation system is developed with a modular software (PALM, from the Centre Européen de Recherche et de Formation Avancée en Calcul Scientifique), and is based on the Best Linear Unbiased Estimator method. Data from a maximum of 186 gauge stations are assimilated over France. This first study focuses on the selection of the best model variables for the assimilation process : root zone layer only or root and sub root layers taken together or apart. Two versions of SIM, including or not an exponential profile of hydraulic conductivity in the soil, are tested, and a set of classical hydrologic scores will be performed in order to describe the performances of the experiments. The impact of this improvement of the initial state of the model on ensemble streamflow forecasts scores will be assessed in a subsequent work.

  9. Potential effects of climate change on streamflow, eastern and western slopes of the Sierra Nevada, California and Nevada

    USGS Publications Warehouse

    Jeton, A.E.; Dettinger, M.D.; Smith, Jody L.

    1996-01-01

    Precipitation-runoff models of the East Fork Carson and North Fork American Rivers were developed and calibrated for use in evaluating the sensitivity of streamflow in the north-central Sierra Nevada to climate change. The East Fork Carson River drains part of the rain-shadowed, eastern slope of the Sierra Nevada and is generally higher than the North Fork American River, which drains the wetter, western slope. First, a geographic information system was developed to describe the spatial variability of basin characteristics and to help estimate model parameters. The result was a partitioning of each basin into noncontiguous, but hydrologically uniform, land units. Hydrologic descriptions of these units were developed and the Precipitation- Runoff Modeling System (PRMS) was used to simulate water and energy balances for each unit in response to daily weather conditions. The models were calibrated and verified using historical streamflows over 22-year (Carson River) and 42-year (American River) periods. Simulated annual streamflow errors average plus 10 percent of the observed flow for the East Fork Carson River basin and plus 15 percent for the North Fork American River basin. Interannual variability is well simulated overall, but, at daily scales, wet periods are simulated more accurately than drier periods. The simulated water budgets for the two basins are significantly different in seasonality of streamflow, sublimation, evapotranspiration, and snowmelt. The simulations indicate that differences in snowpack and snowmelt timing can play pervasive roles in determining the sensitivity of water resources to climate change, in terms of both resource availability and amount. The calibrated models were driven by more than 25 hypothetical climate-change scenarios, each 100 years long. The scenarios were synthesized and spatially disaggregated by methods designed to preserve realistic daily, monthly, annual, and spatial statistics. Simulated streamflow timing was not very

  10. Recent bark beetle outbreaks have little impact on streamflow in the Western United States

    NASA Astrophysics Data System (ADS)

    Slinski, Kimberly M.; Hogue, Terri S.; Porter, Aaron T.; McCray, John E.

    2016-07-01

    In the Western United States (US), the current mountain pine beetle (MPB; Dendroctonus ponderosae) epidemic has affected more than five million hectares since its start in 1996, including headwater catchments that supply water to much of the Western US. There is widespread concern that the hydrologic consequences of the extensive pine tree die-off will impact water supply across the Western US. While forest disturbance studies have shown that streamflow increases in response to tree harvest, the actual effect of bark beetle infestations on water supply remains widely debated. The current study evaluates watershed-level response following bark beetle outbreak for 33 watersheds in seven western states. Streamflow records were investigated to assess whether the timing and amount of stream discharge during bark beetle outbreak and early recovery periods were significantly different to pre-outbreak conditions. Results show no significant modification in peak flows or average daily streamflow following bark beetle infestation, and that climate variability may be a stronger driver of streamflow patterns and snowmelt timing than chronic forest disturbance.

  11. Snow cover, snowmelt and runoff in the Himalayan River basins

    NASA Technical Reports Server (NTRS)

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

    1988-01-01

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

  12. Impacts of Forecasted Climate Change on Snowpack, Glacier Recession, and Streamflow in the Nooksack River Basin

    NASA Astrophysics Data System (ADS)

    Murphy, R. D.; Mitchell, R. J.; Bandaragoda, C.; Grah, O. J.

    2015-12-01

    Like many watersheds in the North Cascades Mountain range, streamflow in the Nooksack River is strongly influenced by precipitation and snowmelt in the spring and glacial melt in the warmer summer months. With a maritime climate and a high relief basin with glacial ice (3400 hectares), the streamflow response in the Nooksack is sensitive to increases in temperature, thus forecasting the basins response to future climate is of vital importance for water resources planning purposes. The watershed (2000 km2) in the northwest of Washington, USA, is a valuable freshwater resource for regional municipalities, industry, and agriculture, and provides critical habitat for endangered salmon species. Due to a lack of spatially distributed long-term historical weather observations in the basin for downscaling purposes, we apply publically available statistically derived 1/16 degree gridded surface data along with the Distributed Hydrology Soil Vegetation Model (DHSVM; Wigmosta et al., 1992) with newly developed coupled dynamic glacier model (Clarke et al., 2015) to simulate hydrologic processes in the Nooksack River basin. We calibrate and validate the DHSVM to observed glacial mass balance and glacial ice extent as well as to observed daily streamflow and SNOTEL data in the Nooksack basin. For the historical period, we model using a gridded meteorological forcing data set (1950-2010; Livneh et al., 2013). We simulate forecasted climate change impacts, including glacial recession on streamflow, using gridded daily statically downscaled data from global climate models of the CMIP5 with RCP4.5 and RCP8.5 forcing scenarios developed using the multivariate adaptive constructed analogs method (Abatzoglou and Brown, 2011). Simulation results project an increase in winter streamflows due to more rainfall rather than snow, and a decrease in summer flows with a general shift in peak spring flows toward earlier in the spring. Glacier melt contribution to streamflow initially increases

  13. Reducing streamflow forecast uncertainty: Application and qualitative assessment of the upper klamath river Basin, Oregon

    USGS Publications Warehouse

    Hay, L.E.; McCabe, G.J.; Clark, M.P.; Risley, J.C.

    2009-01-01

    The accuracy of streamflow forecasts depends on the uncertainty associated with future weather and the accuracy of the hydrologic model that is used to produce the forecasts. We present a method for streamflow forecasting where hydrologic model parameters are selected based on the climate state. Parameter sets for a hydrologic model are conditioned on an atmospheric pressure index defined using mean November through February (NDJF) 700-hectoPascal geopotential heights over northwestern North America [Pressure Index from Geopotential heights (PIG)]. The hydrologic model is applied in the Sprague River basin (SRB), a snowmelt-dominated basin located in the Upper Klamath basin in Oregon. In the SRB, the majority of streamflow occurs during March through May (MAM). Water years (WYs) 1980-2004 were divided into three groups based on their respective PIG values (high, medium, and low PIG). Low (high) PIG years tend to have higher (lower) than average MAM streamflow. Four parameter sets were calibrated for the SRB, each using a different set of WYs. The initial set used WYs 1995-2004 and the remaining three used WYs defined as high-, medium-, and low-PIG years. Two sets of March, April, and May streamflow volume forecasts were made using Ensemble Streamflow Prediction (ESP). The first set of ESP simulations used the initial parameter set. Because the PIG is defined using NDJF pressure heights, forecasts starting in March can be made using the PIG parameter set that corresponds with the year being forecasted. The second set of ESP simulations used the parameter set associated with the given PIG year. Comparison of the ESP sets indicates that more accuracy and less variability in volume forecasts may be possible when the ESP is conditioned using the PIG. This is especially true during the high-PIG years (low-flow years). ?? 2009 American Water Resources Association.

  14. Trends in precipitation and streamflow and changes in stream morphology in the Fountain Creek watershed, Colorado, 1939-99

    USGS Publications Warehouse

    Stogner, Robert W.

    2000-01-01

    The Fountain Creek watershed, located in and along the eastern slope of the Front Range section of the southern Rocky Mountains, drains approximately 930 square miles of parts of Teller, El Paso, and Pueblo Counties in eastern Colorado. Streamflow in the watershed is dominated by spring snowmelt runoff and storm runoff during the summer monsoon season. Flooding during the 1990?s has resulted in increased streambank erosion. Property loss and damage associated with flooding and bank erosion has cost area residents, businesses, utilities, municipalities, and State and Federal agencies millions of dollars. Precipitation (4 stations) and streamflow (6 stations) data, aerial photographs, and channel reconnaissance were used to evaluate trends in precipitation and streamflow and changes in channel morphology. Trends were evaluated for pre-1977, post-1976, and period-of-record time periods. Analysis revealed the lack of trend in total annual and seasonal precipitation during the pre-1977 time period. In general, the analysis also revealed the lack of trend in seasonal precipitation for all except the spring season during the post-1976 time period. Trend analysis revealed a significant upward trend in long-term (period of record) total annual and spring precipitation data, apparently due to a change in total annual precipitation throughout the Fountain Creek watershed. During the pre-1977 time period, precipitation was generally below average; during the post- 1976 time period, total annual precipitation was generally above average. During the post- 1976 time period, an upward trend in total annual and spring precipitation was indicated at two stations. Because two of four stations evaluated had upward trends for the post-1976 period and storms that produce the most precipitation are isolated convection storms, it is plausible that other parts of the watershed had upward precipitation trends that could affect trends in streamflow. Also, because of the isolated nature of

  15. Streamflow predictions in Alpine Catchments by using artificial neural networks. Application in the Alto Genil Basin (South Spain)

    NASA Astrophysics Data System (ADS)

    Jimeno-Saez, Patricia; Pegalajar-Cuellar, Manuel; Pulido-Velazquez, David

    2017-04-01

    This study explores techniques of modeling water inflow series, focusing on techniques of short-term steamflow prediction. An appropriate estimation of streamflow in advance is necessary to anticipate measures to mitigate the impacts and risks related to drought conditions. This study analyzes the prediction of future streamflow of nineteen subbasins in the Alto-Genil basin in Granada (Southeast of Spain). Some of these basin streamflow have an important component of snowmelt due to part of the system is located in Sierra Nevada Mountain Range, the highest mountain of continental Spain. Streamflow prediction models have been calibrated using time series of historical natural streamflows. The available streamflow measurements have been downloaded from several public data sources. These original data have been preprocessed to turn them to the original natural regime, removing the anthropic effects. The missing values in the adopted horizon period to calibrate the prediction models have been estimated by using a Temez hydrological balance model, approaching the snowmelt processes with a hybrid degree day method. In the experimentation, ARIMA models are used as baseline method, and recurrent neural networks ELMAN and nonlinear autoregressive neural network (NAR) to test if the prediction accuracy can be improved. After performing the multiple experiments with these models, non-parametric statistical tests are applied to select the best of these techniques. In the experiments carried out with ARIMA, it is concluded that ARIMA models are not adequate in this case study due to the existence of a nonlinear component that cannot be modeled. Secondly, ELMAN and NAR neural networks with multi-start training is performed with each network structure to deal with the local optimum problem, since in neural network training there is a very strong dependence on the initial weights of the network. The obtained results suggest that both neural networks are efficient for the short

  16. Snowmelt as a driver of ecosystem response in water limited mountain forests of the Western U.S.

    NASA Astrophysics Data System (ADS)

    Molotch, N. P.; Trujillo, E.

    2015-12-01

    Recent large-scale changes in snow cover over Western North America associated with climate warming may have widespread impacts on water availability. These changes have potentially varied impacts on water availability as snowmelt influences, soil moisture, streamflow, and evapotranspiration. These changes may significantly alter runoff production and gross primary productivity in mountain forests. Analysis of remotely sensed and in situ soil moisture data indicate strong sensitivities of the timing of peak soil moisture to the timing of snowmelt. Observations of vegetation greenness indicate strong forest and understory growth dependencies associated with snow accumulation, snowmelt, and soil moisture with peak snow water equivalent explaining 40-50% of inter-annual greenness variability in the Rocky Mountains. Examples of these dependencies will be presented based on the 2012 drought in the Southwestern US whereby near record low snow accumulation and record high potential evapotranspiration have resulted in record low forest greening as evident in the 30+ year satellite record. Forest response to aridity in 2012 was exacerbated by forest disturbance with greenness anomalies 90% greater in magnitude in Bark Beetle and Spruce Budworm affected areas versus undisturbed areas and 182% greater in magnitude in areas impacted by fire. Greenness sensitivities to aridity showed seasonal dependencies with record high Normalized Difference Vegetation Index (NDVI) values in April (14% above average) and record low NDVI values in July (7% below average). Gross primary productivity estimates from the Moderate Resolution Imaging Spectroradiometer (MODIS) and from the Niwot Ridge, Colorado Ameriflux tower indicate record high April GPP (30% and 90% above average for MODIS and the tower, respectively) and record low July GPP (19% and 30% below average, respectively). These energy, water, ecosystem relationships indicate that the sensitivity of ecosystems to changes in climate is

  17. Changes in seasonality and timing of peak streamflow in snow and semi-arid climates of the north-central United States, 1910–2012

    USGS Publications Warehouse

    Ryberg, Karen R.; Akyüz, F. Adnan; Wiche, Gregg J.; Lin, Wei

    2015-01-01

    Changes in the seasonality and timing of annual peak streamflow in the north-central USA are likely because of changes in precipitation and temperature regimes. A source of long-term information about flood events across the study area is the U.S. Geological Survey peak streamflow database. However, one challenge of answering climate-related questions with this dataset is that even in snowmelt-dominated areas, it is a mixed population of snowmelt/spring rain generated peaks and summer/fall rain generated peaks. Therefore, a process was developed to divide the annual peaks into two populations, or seasons, snowmelt/spring, and summer/fall. The two series were then tested for the hypotheses that because of changes in precipitation regimes, the odds of summer/fall peaks have increased and, because of temperature changes, snowmelt/spring peaks happen earlier. Over climatologically and geographically similar regions in the north-central USA, logistic regression was used to model the odds of getting a summer/fall peak. When controlling for antecedent wet and dry conditions and geographical differences, the odds of summer/fall peaks occurring have increased across the study area. With respect to timing within the seasons, trend analysis showed that in northern portions of the study region, snowmelt/spring peaks are occurring earlier. The timing of snowmelt/spring peaks in three regions in the northern part of the study area is earlier by 8.7– 14.3 days. These changes have implications for water interests, such as potential changes in lead-time for flood forecasting or changes in the operation of flood-control dams.

  18. Spatio-temporal snowmelt variability across the headwaters of the Southern Rocky Mountains

    NASA Astrophysics Data System (ADS)

    Fassnacht, S. R.; López-Moreno, J. I.; Ma, C.; Weber, A. N.; Pfohl, A. K. D.; Kampf, S. K.; Kappas, M.

    2017-09-01

    Understanding the rate of snowmelt helps inform how water stored as snow will transform into streamflow. Data from 87 snow telemetry (SNOTEL) stations across the Southern Rocky Mountains were used to estimate spatio-temporal melt factors. Decreases in snow water equivalent were correlated to temperature at these monitoring stations for eight half-month periods from early March through late June. Time explained 70% of the variance in the computed snow melt factors. A residual linear correlation model was used to explain subsequent spatial variability. Longitude, slope, and land cover type explained further variance. For evergreen trees, canopy density was relevant to find enhanced melt rates; while for all other land cover types, denoted as non-evergreen, lower melt rates were found at high elevation, high latitude and north facing slopes, denoting that in cold environments melting is less effective than in milder sites. A change in the temperature sensor about mid-way through the time series (1990 to 2013) created a discontinuity in the temperature dataset. An adjustment to the time series yield larger computed melt factors.

  19. Snowmelt runoff modeling: Limitations and potential for mitigating water disputes

    NASA Astrophysics Data System (ADS)

    Kult, Jonathan; Choi, Woonsup; Keuser, Anke

    2012-04-01

    SummaryConceptual snowmelt runoff models have proven useful for estimating discharge from remote mountain basins including those spanning the various ranges of the Himalaya. Such models can provide water resource managers with fairly accurate predictions of water availability for operational purposes (e.g. irrigation and hydropower). However, these models have limited ability to address characteristic components of water disputes such as diversions, storage and withholding. Contemporary disputes between India and Pakistan surrounding the snowmelt-derived water resources of the Upper Indus Basin highlight the need for improved water balance accounting methods. We present a research agenda focused on providing refined hydrological contributions to water dispute mitigation efforts.

  20. Spring snowmelt variability in northern Eurasia 2000-2007

    NASA Astrophysics Data System (ADS)

    Bartsch, A.; Naeimi, V.; McCallum, I.; Shvidenko, A.; Wagner, W.

    2009-04-01

    Snowmelt dynamics play an essential role in the hydrological cycle of northern latitudes. Entire northern Eurasia is seasonally covered by snow. It instantaneously impacts not only surface hydrology and the energy budget but also terrestrial biota and thus the carbon cycle. Scatterometer such as SeaWinds Quikscat (Ku-band) are sensitive to changes at snow surfaces due to thaw and provide several measurements per day at high latitudes. Diurnal differences (frozen in the morning, thawed in the evening) are investigated in a range of studies since they indicate exactly when snowmelt is taking place. The actual number of dates of snow thaw is of most interest for glacier mass balance studies but the final disappearance of snow together with the length of spring thaw is required in regions with seasonal snow cover. Clusters of consecutive days of diurnal cycling of freeze/thaw are characteristic for the final snowmelt period in boreal and tundra environments. The start, end and duration of such periods give insight into spring CO2 emissions, vegetation fire prediction and river runoff behaviour. Results of the clustering of diurnal thaw and refreeze days as detected from active microwave satellite data over polar Eurasia is presented in this paper. The aim is the monitoring of spring snowmelt variability for assessment of impact of climate change on hydrology and energy budget. SeaWinds Quikscat measurements are available since 1999. The first entire snowmelt period on the northern hemisphere is covered in 2000. Large changes in backscatter between morning and evening acquisitions are characteristic for the snowmelt period, when freezing takes place over night and thawing of the surface during the day. A change from volume to surface scattering occurs in case of melting. When significant changes due to freeze/thaw cycling cease, closed snow cover also disappears. The exact day of year of beginning and end of freeze/thaw cycling can be clearly determined with

  1. The Snowmelt-Runoff Model (SRM) user's manual

    NASA Technical Reports Server (NTRS)

    Martinec, J.; Rango, A.; Major, E.

    1983-01-01

    A manual to provide a means by which a user may apply the snowmelt runoff model (SRM) unaided is presented. Model structure, conditions of application, and data requirements, including remote sensing, are described. Guidance is given for determining various model variables and parameters. Possible sources of error are discussed and conversion of snowmelt runoff model (SRM) from the simulation mode to the operational forecasting mode is explained. A computer program is presented for running SRM is easily adaptable to most systems used by water resources agencies.

  2. An Assessment of Melting Season Streamflow Forecasts using EPS for a Snow Dominated Basin in Turkey

    NASA Astrophysics Data System (ADS)

    Ertaş, Cansaran; Şensoy, Aynur; Akkol, Bulut; Şorman, Arda; Uysal, Gökçen; Çoşkun, Cihan

    2016-04-01

    In many mountainous regions, snowmelt makes significant contribution to streamflow, particularly during spring and summer months. Therefore, runoff modeling and forecasting during spring and early summer is important in terms of energy and water resources management. In this study, the Upper Euphrates Basin (10,275 km2 area and elevation range of 1125-3500 m) located at the headwater of Euphrates River, one of Turkey's most important rivers, is selected as the application area. In this region, snowmelt runoff constitutes approximately 2/3 in volume of the total yearly runoff. The aim of the study is to make a forward-oriented, medium-range flow forecasting using Ensemble Prediction System (EPS) which is a pioneer study for Turkey. Conceptual hydrological model HBV, which has a common usage in the literature, is chosen to predict streamflows. According to preliminary results, Nash-Sutcliffe model efficiencies are 0.85 for calibration (2001-2008) and 0.71 for validation (2009-2014) respectively. After calibrating/validating the hydrologic model, EPS data including 51 different combinations produced by ECMWF is used as probability based weather forecasts. Melting period during March-June of 2009-2015 is chosen as the forecast period. The probabilistic skill of EPS based hydrological model results are analyzed to verify the ensemble forecasts.

  3. Assessing Hydrological Uncertainties Using the SWAT Model to Simulate Streamflow Over the Alpine Himalayas

    NASA Astrophysics Data System (ADS)

    Lakshmi, V.; Kumar, B.; Patra, K. C.

    2016-12-01

    Hindu-Kush Himalayas are the most topographic, climatic and bio-diverse diverse region in the world. Therefore, modelers should be aware of the different kind of uncertainties arising during hydrological modeling in this area. Uncertainties in the modeling outputs are due to input data, model structure and model parameters. SWAT model is a semi-distributed model whose structure can be changed by considering different hydrological processes. In this study, we tried to address the process uncertainties with changes in the SWAT model structure and parameters in the large Himalayan River Basin Gandak. To achieve this, streamflow is simulated with the three SWAT model structures (i) Land phase (ii) Land and Snowmelt Phase (iii) Land and Snowmelt phase with elevation band approach. We also address the uncertainties arising due to forcing input DEM grid size with the best model structure. The model simulation was achieved with the standard automatic calibration procedure of SUFI-2/SWAT-Cup for 2000-2007, using six streamflow gauge stations. The model results reveal that model uncertainties are minimal for model structure (iii). Also, model uncertainties vary with the DEM grid size and it is minimal for DEM grid size >300m.

  4. High-Elevation Evapotranspiration Estimates during Drought: Using Streamflow and LiDAR Snow Observations to Close the Upper Tuolumne River Basin Water Balance

    NASA Astrophysics Data System (ADS)

    Henn, B. M.; Painter, T. H.; McGurk, B. J.; Flint, A. L.; White, V.; Lundquist, J. D.

    2016-12-01

    High-elevation spatial and temporal distributions of key hydrologic variables, such as snow water equivalent (SWE), precipitation, basin storage and evapotranspiration (ET) are difficult to observe due to the sparse coverage of existing observational networks. Airborne LiDAR provides remotely sensed, high-resolution observations of snow depth, though there are uncertainties in the estimation of SWE from LiDAR due to uncertain snow density and uncertain baselines in areas with glaciers and permanent snowfields. Streamflow observations offer another perspective on these distributions, as streamflow spatially integrates the basin's snowmelt response minus ET and increases in storage. By comparing distributed streamflow observations from multiple nested and adjacent basins with LiDAR-based SWE estimates, we verify their hydrologic agreement and seek to infer largely unobserved quantities such as ET. In this study, we use LiDAR observations from the NASA Airborne Snow Observatory (ASO) over the upper Tuolumne River basin in Yosemite National Park, over water years 2013-2015, during a period of historic drought in California. Streamflow time series from multiple sub-basins are available from the Yosemite Hydroclimate Network. For each sub-basin in the Tuolumne domain, we compare ASO SWE volumes from each LiDAR flight plus subsequent precipitation inputs with streamflow volumes from the flight date to 30 September. This water balance approach shows that snowmelt plus precipitation exceeds streamflow by relatively consistent amounts (100-200 mm over the warm season) across subbasins and years. Simple hydrologic models (calibrated to match the streamflow, LiDAR SWE and precipitation inputs for each subbasin) and point soil moisture measurements suggest that this difference corresponds to ET, with basin storage changes relatively small in comparison. This application suggests that LiDAR snow observations may shed light on uncertain aspects of hydrologic science.

  5. Biological consequences of earlier snowmelt from desert dust deposition in alpine landscapes

    PubMed Central

    Steltzer, Heidi; Landry, Chris; Painter, Thomas H.; Anderson, Justin; Ayres, Edward

    2009-01-01

    Dust deposition to mountain snow cover, which has increased since the late 19th century, accelerates the rate of snowmelt by increasing the solar radiation absorbed by the snowpack. Snowmelt occurs earlier, but is decoupled from seasonal warming. Climate warming advances the timing of snowmelt and early season phenological events (e.g., the onset of greening and flowering); however, earlier snowmelt without warmer temperatures may have a different effect on phenology. Here, we report the results of a set of snowmelt manipulations in which radiation-absorbing fabric and the addition and removal of dust from the surface of the snowpack advanced or delayed snowmelt in the alpine tundra. These changes in the timing of snowmelt were superimposed on a system where the timing of snowmelt varies with topography and has been affected by increased dust loading. At the community level, phenology exhibited a threshold response to the timing of snowmelt. Greening and flowering were delayed before seasonal warming, after which there was a linear relationship between the date of snowmelt and the timing of phenological events. Consequently, the effects of earlier snowmelt on phenology differed in relation to topography, which resulted in increasing synchronicity in phenology across the alpine landscape with increasingly earlier snowmelt. The consequences of earlier snowmelt from increased dust deposition differ from climate warming and include delayed phenology, leading to synchronized growth and flowering across the landscape and the opportunity for altered species interactions, landscape-scale gene flow via pollination, and nutrient cycling. PMID:19564599

  6. Biological consequences of earlier snowmelt from desert dust deposition in alpine landscapes.

    PubMed

    Steltzer, Heidi; Landry, Chris; Painter, Thomas H; Anderson, Justin; Ayres, Edward

    2009-07-14

    Dust deposition to mountain snow cover, which has increased since the late 19(th) century, accelerates the rate of snowmelt by increasing the solar radiation absorbed by the snowpack. Snowmelt occurs earlier, but is decoupled from seasonal warming. Climate warming advances the timing of snowmelt and early season phenological events (e.g., the onset of greening and flowering); however, earlier snowmelt without warmer temperatures may have a different effect on phenology. Here, we report the results of a set of snowmelt manipulations in which radiation-absorbing fabric and the addition and removal of dust from the surface of the snowpack advanced or delayed snowmelt in the alpine tundra. These changes in the timing of snowmelt were superimposed on a system where the timing of snowmelt varies with topography and has been affected by increased dust loading. At the community level, phenology exhibited a threshold response to the timing of snowmelt. Greening and flowering were delayed before seasonal warming, after which there was a linear relationship between the date of snowmelt and the timing of phenological events. Consequently, the effects of earlier snowmelt on phenology differed in relation to topography, which resulted in increasing synchronicity in phenology across the alpine landscape with increasingly earlier snowmelt. The consequences of earlier snowmelt from increased dust deposition differ from climate warming and include delayed phenology, leading to synchronized growth and flowering across the landscape and the opportunity for altered species interactions, landscape-scale gene flow via pollination, and nutrient cycling.

  7. Real-time streamflow conditions

    USGS Publications Warehouse

    Graczyk, David J.; Gebert, Warren A.

    1996-01-01

    Would you like to know streamflow conditions before you go fishing in Wisconsin or in more distant locations? Real-time streamflow data throughout Wisconsin and the United States are available on the Internet from the U.S. Geological Survey. You can see if the stream you are interested in fishing is high due to recent rain or low because of an extended dry spell. Flow conditions at more than 100 stream-gaging stations located throughout Wisconsin can be viewed by accessing the Wisconsin District Home Page at: http://wwwdwimdn.er.usgs.gov

  8. Understanding the variations in the timing of daily streamflow peak during melt season

    NASA Astrophysics Data System (ADS)

    Kumar, M.; Chen, X.; Winstral, A. H.; Wang, R.; Marks, D. G.

    2015-12-01

    Previous studies have shown that gauge-observed daily streamflow peak times (DPT) during spring snowmelt can exhibit distinct temporal shifts through the season. These shifts have been attributed to three processes that affect the timing of snowmelt arrival: 1) melt flux translation through the snowpack or percolation, 2) surface and subsurface flow of melt from the base of snowpacks to streams, and 3) translation of water flux in the streams to streamgage stations. The goal of this study is to evaluate and quantify how these processes affect observed DPT variations at the Reynolds Mountain East (RME) research catchment in southwest Idaho, USA. To accomplish this goal, DPT was simulated for the RME catchment over a period of 25 water years using a modified snowmelt model, iSnobal, and a hydrology model, PIHM. The influence of each controlling process was then evaluated by simulating the DPT with and without the process under consideration. Both intra- and inter-seasonal variability in DPT were evaluated. Results indicate that the average DPT is dominantly influenced by subsurface flow, whereas the seasonal variations in DPT are primarily controlled by percolation through snow. In addition to the three processes previously identified in the literature, processes governing the time for ripening of the snowpack are identified as additionally influencing DPT variability. Results also indicate that the relative dominance of each control varies through the melt season, and between wet and dry years. The results could be used for supporting DPT prediction efforts and for prioritization of observables for DPT determination.

  9. Coupling a Physically Based and Spatially Distributed Snowmelt Model with a Flowpath Model, Green Lakes Valley, Colorado Front Range

    NASA Astrophysics Data System (ADS)

    Liu, F.; Williams, M. W.; Ackerman, T.

    2003-12-01

    Spatially distributed estimates of snow deposition and melt allow us to better understand the interaction between hydrology and topographic structure and climate in mountain basins. Here we report on initial efforts to add a physical based and spatially distributed energy balance snowmelt model, ISNOBAL to the XTOP_PRMS model, a flowpath model coupling the TOPMODEL and Precipitation Runoff Modeling System within the Module Modeling System (MMS). This procedure was demonstrated at the 8-ha Martinelli and the 220-ha Green Lake 4 (GL4) catchments in the Green Lakes Valley, Colorado Front Range. In the pilot study using a temperature index snowmelt algorithm in the XTOP_PRMS model, streamflow discharge measured in 1996 was used to calibrate parameters and streamflow discharge was simulated from 1997 to 2000. The results showed that the discharge simulation was relatively successful at the 8-ha Martinelli catchment, with a Nash-Sutcliffe efficiency of 0.76. The t-test for paired means indicated that the prediction of discharge was not significantly different from the observation at α = 0.05 (n = 1611, p = 0.6). However, the discharge simulation was relatively poor at the GL4 catchment, with a Nash-Sutcliffe efficiency of only 0.54. Moreover, the difference between the predicted and observed values was significant at α = 0.05 (n = 1611, p = 0.005). It is believed that the poor performance of the XTOP_PRMS model at the GL4 catchment was due to use of the temperature index snowmelt algorithm as well as the coarse (daily) temporal resolution of the air temperature in the model. To resolve this problem, we report on our efforts to incorporate the hourly mode ISNOBAL with the XTOP_PRMS model within the MMS. High temporal resolution time-series images of climate surfaces such as air temperature, humidity, wind speed, precipitation, and solar and thermal radiation are generated using the Image Processing Workbench (IPW) and a combination of 3 to 5 point measurements

  10. Snowmelt Runoff From Planted Conifers in Southwestern Wisconsin

    Treesearch

    Richard S. Sartz; David N. Tolsted

    1976-01-01

    Snowmelt overland flow was measured for one season from 10-year-old plantations of red pine, Norway spruce, European larch, and from old field control plots, on both north and south slopes. Pine and spruce plots produced more runoff than larch and old field plots; and south slope plots produced more runoff than north slope plots.

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

    USGS Publications Warehouse

    Chase, K.J.

    2011-01-01

    percent higher than observed for the test period. Downstream from the reservoir, simulated mean annual streamflow was 17 percent lower than observed streamflow for the calibration period and 12 percent lower than observed streamflow for the test period. Simulated mean April-July streamflow downstream from the reservoir was 13 percent lower than observed streamflow for the calibration period and 6 percent lower than observed streamflow for the test period. Calibrating to solar radiation, potential evapotranspiration, and snow-covered area improved the model representation of evapotranspiration, snow accumulation, and snowmelt processes. Simulated basin mean monthly solar radiation values for both the calibration and test periods were within 9 percent of observed values except during the month of December (28 percent different). Simulated basin potential evapotranspiration values for both the calibration and test periods were within 10 percent of observed values except during the months of January (100 percent different) and February (13 percent different). The larger percent errors in simulated potential evaporation occurred in the winter months when observed potential evapotranspiration values were very small; in January the observed value was 0.000 inches and in February the observed value was 0.009 inches. Simulated start of melting of the snowpack occurred at about the same time as observed start of melting. The simulated snowpack accumulated to 90-100 percent snow-covered area 1 to 3 months earlier than observed snowpack. This overestimated snowpack during the winter corresponded to underestimated streamflow during the same period. In addition to the primary-parameter file, four other parameter files were created: for a "recent" period (1991-2005), a historical period (1967-90), a "wet" period (1989-97), and a "dry" period (1998-2005). For each data file of projected precipitation and air temperature, a single parameter file can be used to simulate a s

  12. Detection and attribution of streamflow timing changes to climate change in the Western United States

    USGS Publications Warehouse

    Hidalgo, H.G.; Das, T.; Dettinger, M.D.; Cayan, D.R.; Pierce, D.W.; Barnett, T.P.; Bala, G.; Mirin, A.; Wood, A.W.; Bonfils, Celine; Santer, B.D.; Nozawa, T.

    2009-01-01

    This article applies formal detection and attribution techniques to investigate the nature of observed shifts in the timing of streamflow in the western United States. Previous studies have shown that the snow hydrology of the western United States has changed in the second half of the twentieth century. Such changes manifest themselves in the form of more rain and less snow, in reductions in the snow water contents, and in earlier snowmelt and associated advances in streamflow "center" timing (the day in the "water-year" on average when half the water-year flow at a point has passed). However, with one exception over a more limited domain, no other study has attempted to formally attribute these changes to anthropogenic increases of greenhouse gases in the atmosphere. Using the observations together with a set of global climate model simulations and a hydrologic model (applied to three major hydrological regions of the western United States_the California region, the upper Colorado River basin, and the Columbia River basin), it is found that the observed trends toward earlier "center" timing of snowmelt-driven streamflows in the western United States since 1950 are detectably different from natural variability (significant at the p < 0.05 level). Furthermore, the nonnatural parts of these changes can be attributed confidently to climate changes induced by anthropogenic greenhouse gases, aerosols, ozone, and land use. The signal from the Columbia dominates the analysis, and it is the only basin that showed a detectable signal when the analysis was performed on individual basins. It should be noted that although climate change is an important signal, other climatic processes have also contributed to the hydrologic variability of large basins in the western United States. ?? 2009 American Meteorological Society.

  13. Potential Impacts of Climate Change on Streamflow and Flooding in Snow Dominated Forest Basins

    SciTech Connect

    Wigmosta, Mark S.; Leung, Lai R.

    2003-01-01

    Changes in climate resulting from the buildup of greenhouse gases in the atmosphere may impact significantly the frequency and magnitude of flooding in forested watersheds through changes in snowpack, soil moisture, and runoff production. The level of impact will vary considerably among watersheds depending on the climate regime and hydrologic characteristics of the catchments. Two forested watersheds in the Pacific Northwest of the United States, the American River and Middle Fork Flathead River, were studied to examine the influence of long-term global warming on streamflow and flooding in snowmelt dominated basins. These watersheds were selected to compare impacts resulting from changes in the maritime and continental climate regimes associated with the American and Middle Fork Flathead River basins, respectively. Output from a regional climate model was used to drive a distributed hydrologic model under present and future climate conditions corresponding to a doubling of atmospheric CO2. Under the future climate scenario more winter precipitation fell as rain instead of snow producing higher winter flows, a reduced snowpack, and decreased spring and summer flows in the American River. In addition, there was a large increase in the frequency and magnitude of winter flooding, primarily due to an increase in the number of rain-on-snow events. The change was much less dramatic in the Middle Fork Flathead River where flooding generally occurs during spring snowmelt. In this basin, the seasonal pattern of streamflow remains intact and the incidence of flooding was reduced under the future climate scenario. This study suggests the impacts of climate change on streamflow and flooding in forested watersheds are highly region specific.

  14. Ground water occurrence and contributions to streamflow in an alpine catchment, Colorado Front Range

    USGS Publications Warehouse

    Clow, D.W.; Schrott, L.; Webb, R.; Campbell, D.H.; Torizzo, A.O.; Dornblaser, M.

    2003-01-01

    Ground water occurrence, movement, and its contribution to streamflow were investigated in Loch Vale, an alpine catchment in the Front Range of the Colorado Rocky Mountains. Hydrogeomorphologic mapping, seismic refraction measurements, and porosity and permeability estimates indicate that talus slopes are the primary ground water reservoir, with a maximum storage capacity that is equal to, or greater than, total annual discharge from the basin (5.4 ± 0.8 × 106 m3). Although snowmelt and glacial melt provide the majority of annual water flux to the basin, tracer tests and gauging along a stream transect indicate that ground water flowing from talus can account for ≥75% of streamflow during storms and the winter base flow period. The discharge response of talus springs to storms and snowmelt reflects rapid transmittal of water through coarse debris at the talus surface and slower release of water from finer-grained sediments at depth.Ice stored in permafrost (including rock glaciers) is the second largest ground water reservoir in Loch Vale; it represents a significant, but seldom recognized, ground water reservoir in alpine terrain. Mean annual air temperatures are sufficiently cold to support permafrost above 3460 m; however, air temperatures have increased 1.1° to 1.4°C since the early 1990s, consistent with long-term (1976–2000) increases in air temperature measured at other high-elevation sites in the Front Range, European Alps, and Peruvian Andes. If other climatic factors remain constant, the increase in air temperatures at Loch Vale is sufficient to increase the lower elevational limit of permafrost by 150 to 190 m. Although this could cause a short-term increase in streamflow, it may ultimately result in decreased flow in the future.

  15. Remote Sensing Applications to Improve Seasonal Forecasting of Streamflow and Reservoir Storage in the Upper Snake River Basin

    NASA Astrophysics Data System (ADS)

    McGuire, M.; Wood, A. W.; Andreadis, K.; van Rheenen, N.; Lettenmaier, D. P.

    2003-12-01

    Mountain snowmelt contributes over eighty percent of the water supply in the Western U.S. Accurate estimates and forecasts of snow cover and snowmelt are important to many local, state, and Federal agencies that have interests in agriculture, hydropower, and recreation. Water resource managers depend on accurate water supply predictions to allocate a finite supply of water to often competing demands. Although quantitative forecasts of seasonal snowmelt runoff have been made at many locations in the West for over 50 years, these forecasts are limited by accurate knowledge of winter season precipitation and snow accumulation in remote areas, which presently are estimated via in situ networks like the NRCS' SNOTEL. We evaluate the potential to improve on methods based solely on in situ observations through a strategy that combines nowcasts of soil moisture, snow water content, and other hydrologic variables using the Variable Infiltration Capacity (VIC) macroscale hydrologic model, updated with a combination of SNOTEL-based estimates of snow water equivalent and remote sensing (MODIS) estimates of snow areal extent. The method is evaluated for the Upper Snake River basin, for which a long-term retrospective VIC run for the period 1950-2002 provides a model climatology, and the basis for a retrospective evaluation of seasonal streamflow forecast skill absent updating. For winters 2001-2 and 2002-3, we evaluate the impact of both replacing and augmenting our updating scheme based on SNOTEL data with corrections from two remote sensing products: course spatial resolution MODIS snow-cover data and, on a more experimental basis, an AMSR snow water equivalent product. In addition to seasonal streamflow forecasts based on an adaptation of the Extended Streamflow Prediction (ESP) method, we implement and evaluate experimental reservoir forecasts produced with the SNAKESIM Snake River reservoir management model for forecasts made in the winters of 2001-2 and 2003-4 for the

  16. Ephemeral-streamflow Induced Focused Recharge in the Desert Southwest (US)

    NASA Astrophysics Data System (ADS)

    Constantz, J. E.; Stonestrom, D. A.

    2015-12-01

    Multiyear studies examined meteorologic and hydrogeologic controls on ephemeral streamflow and focused groundwater recharge at 8 sites across arid and semiarid southwestern regions of the US. Intensive data collection targeted the Great Basin, Mojave Desert, Sonoran Desert, Rio Grande Rift, and Colorado Plateau physiographic areas (USGS Prof. Pap. 1703-C). During the study period (1997-2002), the region went from wetter than normal conditions associated with a strong El Niño climatic pattern (1997-1998) to drier than normal conditions associated with a La Niña climatic pattern. The 1997-1998 El Niño, the strongest in the modern instrumental record, roughly doubled precipitation at the Great Basin, Mojave Desert, and Colorado Plateau study sites. Precipitation at all sites thereafter trended sharply lower, producing moderate- to severe-drought conditions by the end of the study. Streamflow in regional rivers indicated diminishing groundwater recharge, with annual-flow volumes declining to levels of only 10-46% of their respective long-term averages by 2002. Local streamflows showed higher variability, reflecting smaller scales of integration (in time and space) within study-site watersheds. Toward the end of study, extended periods (9-15 months) of zero or negligible flow were observed at half the sites. Summer monsoonal rains generated the majority of streamflow and associated recharge in the Sonoran Desert sites and the more southerly Rio Grande Rift site, whereas winter storms and spring snowmelt dominated the northern and westernmost sites. Proximity to moisture sources and meteorologic fluctuations, in concert with orography, largely control the generation of focused groundwater recharge from ephemeral streamflow, although other aspects (geology, soil, and vegetation) were also identified as factors. Estimates of annual focused infiltration for the research sites ranged from about 105-107 cubic meters from contributing areas that ranged from 26-2,260 square

  17. Executive summary - Assessing the response of Emerald Lake, an alpine watershed in Sequoia National Park, California, to acidification during snowmelt using a simple hydrochemical model

    SciTech Connect

    Hooper, R.P.; West, C.T.; Peters, N.E. )

    1990-01-01

    A simple process-oriented model, called the Alpine Lake Forecaster (ALF), was constructed using data collected from the Integrated Watershed Study of Emerald Lake, Sequoia National Park, California. ALF is able to capture the basic solute patterns during snowmelt in this alpine catchment where groundwater is a minor contributor to streamflow. It includes an empirical representation of primary mineral weathering as the only alkalinity generating mechanism. During a heavy snow year, such as the one used for calibrating the model, the model accurately simulated the surface water chemical change in response to the initial ionic pulse from the snowpack and to the dilution that occurs at peak snowmelt. Because the model does not consider cation exchange, it over-predicts the acidification during the initial period of snowmelt, and therefore is a conservative predictor. However, the minimum alkalinity observed in the main inflows to Emerald Lake and in the lake outflow is accurately simulated by the model. The representation of the lake as simply a missing volume with no additional chemical reactions is supported by the observation. The model predicts a change of 2 to 5 microequiv/L in the minimum alkalinity of the lake outflow during snowmelt if the deposition would have to increase between two and 18 times the current load-alkalinity of the lake; the precise increase depends on hydrologic conditions and on the pattern of solute release from the snowpack. An acidic rainstorm that exhausted the alkalinity of the lake was observed during summer 1984 after the lake had stratified, and is the likely cause of the acidification of Emerald Lake.

  18. An approach for reconstructing past streamflows using a water balance model and tree-ring records in the upper West Walker River basin, California

    NASA Astrophysics Data System (ADS)

    Vittori, J. C.; Saito, L.; Biondi, F.

    2010-12-01

    Historical streamflows in a given river basin can be useful for determining regional patterns of drought and climate, yet such measured data are typically available for the last 100 years at most. To extend the measured record, observed streamflows can be regressed against tree-ring data that serve as proxies for streamflow. This empirical approach, however, cannot account for or test factors that do not directly affect tree-ring growth but may influence streamflow. To reconstruct past streamflows in a more mechanistic way, a seasonal water balance model has been developed for the upper West Walker River basin that uses proxy precipitation and air temperature data derived from tree-ring records as input. The model incorporates simplistic relationships between precipitation and other components of the hydrologic cycle, as well as a component for modeling snow, and operates at a seasonal time scale. The model allows for flexibility in manipulating various hydrologic and land use characteristics, and can be applied to other watersheds. The intent is for the model to investigate sources of uncertainty in streamflow reconstructions, and how factors such as wildfire or changes in vegetation cover could impact estimates of past flows, something regression-based models are not able to do. In addition, the use of a mechanistic water balance model calibrated against proxy climate records can provide information on changes in various components of the water cycle, including the interaction between evapotranspiration, snowmelt, and runoff under warmer climatic regimes.

  19. An assessment of streamflow vulnerability to climate using Hydrologic Landscape classification

    NASA Astrophysics Data System (ADS)

    Jones, C., Jr.; Leibowitz, S. G.; Sawicz, K. A.; Comeleo, R. L.; Stratton, L. E.; Wigington, P. J., Jr.

    2016-12-01

    Identifying regions with similar hydrology is useful for assessing water quality and quantity across the U.S., especially areas that are difficult or costly to monitor. For example, hydrologic landscapes (HLs) have been used to map streamflow variability and assess the spatial distribution of climatic response in Oregon, Alaska, and the Pacific Northwest. HLs have also been applied to assess historic and projected climatic impacts across the Western U.S. In this project, we summarized (1) the HL classification methodology and (2) the utility of using HLs as a tool to classify the vulnerability of streams to climatic changes in the Western U.S. During the HL classification process, we analyzed climate, seasonality, aquifer permeability, terrain, and soil permeability as the primary hydrologic drivers (and precipitation intensity as a secondary driver) associated with large scale hydrologic processes (storage, conveyance, and flow of water into or out of the watershed) in the West. We derived the dominant hydrologic pathways (surface runoff or deep or shallow groundwater) from the HL classification of different catchments to test our hypotheses: 1) Changes in climate will have greater impacts on streamflow in catchments dominated by surface runoff. 2) Catchments historically fed by surface runoff from winter snowmelt in the spring will experience greater impact if precipitation falls as rain instead of snow. We calculated S* (precipitation surplus, which includes snowmelt runoff) as a proxy for streamflow for watersheds across the landscape under historic (1901-2000), modern (1971-2000), and future climate projections (2041-2070) to determine whether future projections of S* fall outside of the range of historic S*. Catchments with projections outside the historic range may be more vulnerable to changes in streamflow. Our results indicate that streams dominated by surface runoff and catchments with spring seasonality are more vulnerable to climatic changes. This

  20. Use of medium-range numerical weather prediction model output to produce forecasts of streamflow

    USGS Publications Warehouse

    Clark, M.P.; Hay, L.E.

    2004-01-01

    he accuracy of precipitation forecasts over the northeastern United States, but overall, the accuracy of MOS-based precipitation forecasts is slightly lower than the raw NCEP forecasts. Four basins in the United States were chosen as case studies to evaluate the value of MRF output for predictions of streamflow. Streamflow forecasts using MRF output were generated for one rainfall-dominated basin (Alapaha River at Statenville, Georgia) and three snowmelt-dominated basins (Animas River at Durango, Colorado: East Fork of the Carson River near Gardnerville, Nevada: and Cle Elum River near Roslyn, Washington). Hydrologic model output forced with measured-station data were used as "truth" to focus attention on the hydrologic effects of errors in the MRF forecasts. Eight-day streamflow forecasts produced using the MOS-corrected MRF output as input (MOS) were compared with those produced using the climatic Ensemble Streamflow Prediction (ESP) technique. MOS-based streamflow forecasts showed increased skill in the snowmelt-dominated river basins, where daily variations in streamflow are strongly forced by temperature. In contrast, the skill of MOS forecasts in the rainfall-dominated basin (the Alapaha River) were equivalent to the skill of the ESP forecasts. Further improvements in streamflow forecasts require more accurate local-scale forecasts of precipitation and temperature, more accurate specification of basin initial conditions, and more accurate model simulations of streamflow. ?? 2004 American Meteorological Society.

  1. Measuring streamflow in Virginia (1999 revision)

    USGS Publications Warehouse

    Moberg, Roger M.; Rice, Karen C.; Powell, Eugene D.

    1999-01-01

    The U.S. Geological Survey (USGS), U.S. Department of the Interior, is the Nation's largest Earth-science information agency. Among its many responsibilities, such as map making and providing information on earthquakes and other natural hazards, the USGS provides information on the Nation's water resources. The USGS has collected and analyzed hydrologic (water-related) information for more than 100 years. In 1889, the first streamflow-gaging station (a site where regular observations of streamflow data are collected) operated in the United States by the USGS was established on the Rio Grande near Embudo, New Mexico. As the need for streamflow data increased, the USGS's streamflow-gaging program has grown to include more than 7,000 continuous-record streamflow-gaging stations. More than 90 percent of these stations are operated with at least partial support from State, local, and other Federal agencies.In Virginia, the Department of Environmental Quality (DEQ) is a major cooperator in the streamflow-gaging program, which consists of 152 continuous-record streamflow-gaging stations located throughout the State (fig. 1). The USGS and DEQ cooperate to publish the annual USGS State data report, "Water Resources Data-Virginia;" this two-volume publication includes streamflow data collected at the 152 streamflow-gaging stations, chemical data collected at more than 24 streamflow-gaging stations, and ground-water data collected from more than 338 wells.

  2. Measuring streamflow in Virginia (2002 revision)

    USGS Publications Warehouse

    Moberg, Roger M.; Rice, Karen C.; Powell, Eugene D.

    2002-01-01

    The U.S. Geological Survey (USGS), U.S. Department of the Interior, is the Nation's largest Earth-science information agency. Among its many responsibilities, such as map making and providing information on earthquakes and other natural hazards, the USGS provides information on the Nation's water resources. The USGS has collected and analyzed hydrologic (water-related) information for more than 100 years. In 1889, the first streamflow-gaging station (a site where regular observations of streamflow data are collected) operated in the United States by the USGS was established on the Rio Grande near Embudo, New Mexico. As the need for streamflow data increased, the USGS's streamflow-gaging program has grown to include more than 7,000 continuous-record streamflow-gaging stations. More than 90 percent of these stations are operated with at least partial support from State, local, or other Federal agencies In Virginia, the Department of Environmental Quality (DEQ) is a major cooperator in the streamflow-gaging program, which consists of 161 continuous-record streamflow-gaging stations located throughout the State (fig. 1). The USGS and DEQ cooperate to publish the annual USGS State data report, 'Water Resources Data-Virginia'; this two-volume publication includes streamflow data collected at the 161 streamflow-gaging stations, chemical data collected at 19 streamflow-gaging stations, and ground-water data collected from more than 250 wells located in Virginia.

  3. Streamflow Necessary for Environmental Maintenance

    NASA Astrophysics Data System (ADS)

    Whiting, Peter J.

    In the last decades, insights from the fields of ecology, geomorphology, and hydrology have been applied to the question of the streamflows necessary for environmental maintenance. For instance, determining the streamflow needed for spawning by salmon or trout requires ascertaining how much water, for how long, and at what time it will be needed? And what flows are necessary for the sustenance of streamside vegetation? Answers to these and similar questions have been sought to minimize environmental degradation in the development or relicensing of water projects, in restoring riverine ecosystems, and in balancing multiple uses for limited water resources. In this contribution, the varieties of environmental maintenance flows applied to rivers are described, as are their fundamental principles. These environmental maintenance flows include flows to maintain aesthetics and recreation, streambed sediment size and its mobility, the channel, its features and continuity, and the floodplain, its wetness regime, and riparian vegetation.

  4. Use of a precipitation-runoff model to simulate natural streamflow conditions in the Methow River basin, Washington

    USGS Publications Warehouse

    Ely, David Matthew; Risley, John C.

    2001-01-01

    Management of the water resources of the Methow River Basin is changing in response to the listing of three species of fish under the Endangered Species Act and the Washington State-legislated watershed-planning process. Management options must be considered that minimize adverse effects on people but meet instream flow needs for fish. This report describes the construction and calibration of the Methow River Basin watershed model and evaluates the accuracy of the model as a predictive tool for assessing the natural instream flow conditions. The term ?natural? instream flow is stressed because surface water within the Basin is used for agricultural irrigation through an extensive system of diversions. The USGS Modular Modeling System was used for the watershed modeling component of the Methow River Basin study. The Geographic Information System Weasel characterized the physical properties of the basin, and the Precipitation-Runoff Modeling System simulated the natural streamflow. Natural streamflow conditions in the Basin were difficult to calibrate because six of the seven streamflow gaging stations are located below irrigation diversions and few streamflow measurements exist for the study area before the diversions were present. Therefore, limited records of natural streamflow conditions were available and estimations concerning some physical processes could not be quantified. Streamflow was simulated for water years 1992-99 to calibrate the model to measured streamflows. Simulated and measured streamflow generally showed close agreement, especially during spring runoff from snowmelt. Low-flow periods, most restrictive to fish habitation, were simulated reasonably well, yet possessed the most uncertainty. Simulations of the total annual runoff as a percentage of measured annual runoff for the 8-year calibration period at seven gaging stations ranged from -33.7 to +30.5 percent with 70 percent of the simulated values within 16 percent. Simulation of water years

  5. Sustained winter streamflow from groundmelt

    Treesearch

    C. Anthony Federer

    1965-01-01

    The watersheds of the Hubbard Brook Experimental Forest in the White Mountains of New Hampshire are among the few small gaged watersheds for which continuous winter streamflow records are obtained while deep snow covers the area. Records show that a remarkably steady flow of between 0.006 and 0.025 area-inch of water per day leaves the watershed in spite of snow depths...

  6. DEBRIS FLOWS AND HYPERCONCENTRATED STREAMFLOWS.

    USGS Publications Warehouse

    Wieczorek, Gerald F.

    1986-01-01

    Examination of recent debris-flow and hyperconcentrated-streamflow events in the western United States reveals (1) the topographic, geologic, hydrologic, and vegetative conditions that affect initiation of debris flows and (2) the wide ranging climatic conditions that can trigger debris flows. Recognition of these physiographic and climatic conditions has aided development of preliminary methods for hazard evaluation. Recent developments in the application of electronic data gathering, transmitting, and processing systems shows potential for real-time hazard warning.

  7. Composition of snowmelt and runoff in northern Michigan

    SciTech Connect

    Cadle, S.H.; Dasch, J.M.; Kopple, R.V.

    1987-03-01

    Snowmelt and runoff were studied during the 1982-1983 and the 1983-1984 winters at the University of Michigan Biological Station, which is located near the northern tip of Michigan's lower peninsula. The first 50% of the snowpack acidity was released in meltwater and rainwater equal to 25% of the original snowpack water content. Interaction between the meltwater and the litter layer produced large changes in the concentrations of most species. Runoff to two streams had high SO/sub 4//sup 2 -/ and very low NO/sub 3//sup -/ concentrations. It is concluded that most of the NO/sub 3//sup -/ is either biologically utilized or retained in the watershed, even during the early snowmelt period at this site. 18 references, 5 figures, 3 tables.

  8. Snowmelt-runoff Model Utilizing Remotely-sensed Data

    NASA Technical Reports Server (NTRS)

    Rango, A.

    1985-01-01

    Remotely sensed snow cover information is the critical data input for the Snowmelt-Runoff Model (SRM), which was developed to simulatke discharge from mountain basins where snowmelt is an important component of runoff. Of simple structure, the model requires only input of temperature, precipitation, and snow covered area. SRM was run successfully on two widely separated basins. The simulations on the Kings River basin are significant because of the large basin area (4000 sq km) and the adequate performance in the most extreme drought year of record (1976). The performance of SRM on the Okutadami River basin was important because it was accomplished with minimum snow cover data available. Tables show: optimum and minimum conditions for model application; basin sizes and elevations where SRM was applied; and SRM strengths and weaknesses. Graphs show results of discharge simulation.

  9. Streamflow characterization and summary of water-quality data collection during the Mississippi River flood, April through July 2011

    USGS Publications Warehouse

    Welch, Heather L.; Barnes, Kimberlee K.

    2013-01-01

    From April through July 2011, the U.S. Geological Survey collected surface-water samples from 69 water-quality stations and 3 flood-control structures in 4 major subbasins of the Mississippi River Basin to characterize the water quality during the 2011 Mississippi River flood. Most stations were sampled at least monthly for field parameters suspended sediment, nutrients, and selected pesticides. Samples were collected at daily to biweekly frequencies at selected sites in the case of suspended sediment. Hydro-carbon analysis was performed on samples collected at two sites in the Atchafalaya River Basin to assess the water-quality implications of opening the Morganza Floodway. Water-quality samples obtained during the flood period were collected at flows well above normal streamflow conditions at the majority of the stations throughout the Mississippi River Basin and its subbasins. Heavy rainfall and snowmelt resulted in high streamflow in the Mississippi River Basin from April through July 2011. The Ohio River Subbasin contributed to most of the flow in the lower Mississippi-Atchafalaya River Subbasin during the months of April and May because of widespread rainfall, whereas snowmelt and precipitation from the Missouri River Subbasin and the upper Mississippi River Subbasin contributed to most of the flow in the lower Mississippi-Atchafalaya River Subbasin during June and July. Peak streamflows from the 2011 flood were higher than peak streamflow during previous historic floods at most the selected streamgages in the Mississippi River Basin. In the Missouri River Subbasin, the volume of water moved during the 1952 flood was greater than the amount move during the 2011 flood. Median concentrations of suspended sediment and total phosphorus were higher in the Missouri River Subbasin during the flood when compared to the other three subbasins. Surface water in the upper Mississippi River Subbasin contained higher median concentrations of total nitrogen, nitrate

  10. Response of streamflow to projected climate change scenarios in an eastern Himalayan catchment of India

    NASA Astrophysics Data System (ADS)

    Senzeba, K. T.; Rajkumari, S.; Bhadra, A.; Bandyopadhyay, A.

    2016-04-01

    Snowmelt run-off model (SRM) based on degree-day approach has been employed to evaluate the change in snow-cover depletion and corresponding streamflow under different projected climatic scenarios for an eastern Himalayan catchment in India. Nuranang catchment located at Tawang district of Arunachal Pradesh with an area of 52 km2 is selected for the present study with an elevation range of 3143-4946 m above mean sea level. Satellite images from October to June of the selected hydrological year 2006-2007 were procured from National Remote Sensing Centre, Hyderabad. Snow cover mapping is done using NDSI method. Based on long term meteorological data, temperature and precipitation data of selected hydrological year are normalized to represent present climatic condition. The projected temperature and precipitation data are downloaded from NCAR's GIS data portal for different emission scenarios (SRES), viz., A1B, A2, B1; and IPCC commitment (non-SRES) scenario for different future years (2020, 2030, 2040 and 2050). Projected temperature and precipitation data are obtained at desired location by spatially interpolating the gridded data and then by statistical downscaling using linear regression. Snow depletion curves for all projected scenarios are generated for the study area and compared with conventional depletion curve for present climatic condition. Changes in cumulative snowmelt depth for different future years are highest under A1B and lowest under IPCC commitment, whereas A2 and B1 values are in-between A1B and IPCC commitment. Percentage increase in streamflow for different future years follows almost the same trend as change in precipitation from present climate under all projected climatic scenarios. Hence, it was concluded that for small catchments having seasonal snow cover, the total streamflow under projected climatic scenarios in future years will be primarily governed by the change in precipitation and not by change in snowmelt depth. Advancing of

  11. Potential impacts of climate change on groundwater recharge and streamflow in a central European low mountain range

    NASA Astrophysics Data System (ADS)

    Eckhardt, K.; Ulbrich, U.

    2003-12-01

    General Circulation Models simulate significant changes of temperature and precipitation over Europe as part of the anthropogenic climate change. In this study, the impacts of climate change on groundwater recharge and streamflow in a central European low mountain range catchment are investigated using a conceptual eco-hydrologic model, a revised version of the Soil and Water Assessment Tool (SWAT). To improve the reliability of our simulations, we compile plant physiological studies concerning the influence of elevated ambient CO 2 concentrations on stomatal conductance and leaf area. Using this information to parameterise the model, we evaluate the impacts of two climate change scenarios, which represent a wide range of assumptions concerning future greenhouse gas emissions and climate sensitivity. The resulting effects on mean annual groundwater recharge and streamflow are small, as increased atmospheric CO 2 levels reduce stomatal conductance thus counteracting increasing potential evapotranspiration induced by the temperature rise and decreasing precipitation. There are, however, more pronounced changes associated with the mean annual cycle of groundwater recharge and streamflow. Our results imply that due to the warming a smaller proportion of the winter precipitation will fall as snow. The spring snowmelt peak therefore is reduced while the flood risk in winter will probably increase. In summer, mean monthly groundwater recharge and streamflow are reduced by up to 50% potentially leading to problems concerning water quality, groundwater withdrawals and hydropower generation.

  12. Estimates of Glacier Mass Loss and Contribution to Streamflow in the Wind River Range in Wyoming: Case Study

    SciTech Connect

    Marks, Jeffrey; Piburn, Jesse; Tootle, Glenn; Kerr, Greg; Oubeidillah, Abdoul

    2014-09-11

    The Wind River Range is a continuous mountain range, approximately 160 km in length, in west-central Wyoming. The presence of glaciers results in meltwater contributions to streamflow during the late summer (July, August, and September: JAS) when snowmelt is decreasing; temperatures are high; precipitation is low; evaporation rates are high; and municipal, industrial, and irrigation water are at peak demands. Therefore, the quantification of glacier meltwater (e.g., volume and mass) contributions to late summer/early fall streamflow is important, given that this resource is dwindling owing to glacier recession. The current research expands upon previous research efforts and identifies two glaciated watersheds, one on the east slope (Bull Lake Creek) and one on the west slope (Green River) of the Wind River Range, in which unimpaired streamflow is available from 1966 to 2006. Glaciers were delineated within each watershed and area estimates (with error) were obtained for the years 1966, 1989, and 2006. Glacier volume (mass) loss (with error) was estimated by using empirically based volume-area scaling relationships. For 1966 to 2006, glacier mass contributions to JAS streamflow on the east slope were approximately 8%, whereas those on the west slope were approximately 2%. Furthermore, the volume-area scaling glacier mass estimates compared favorably with measured (stereo pair remote sensed data) estimates of glacier mass change for three glaciers (Teton, Middle Teton, and Teepe) in the nearby Teton Range and one glacier (Dinwoody) in the Wind River Range.

  13. Hydrology and snowmelt simulation of Snyderville Basin, Park City, and adjacent areas, Summit County, Utah

    USGS Publications Warehouse

    Brooks, Lynette E.; Mason, James L.; Susong, David D.

    1998-01-01

    ground water has the potential to decrease discharge to streams and affect both the amount and quality of surface water in the study area. A comparison of the 1995 to 1994 water budgets emphasizes that the hydrologic system in the study area is very dependent upon the amount of annual precipitation. Although precipitation on the study area was much greater in 1995 than in 1994, most of the additional water resulted in additional streamflow and spring discharge that flows out of the study area. Ground-water levels and groundwater discharge are dependent upon annual precipitation and can vary substantially from year to year.Snowmelt runoff was simulated to assist in estimating ground-water recharge to consolidated rock and unconsolidated valley fill. A topographically distributed snowmelt model controlled by independent inputs of net radiation, meteorological parameters, and snowcover properties was used to calculate the energy and mass balance of the snowcover.

  14. Catchment biophysical drivers of streamflow characteristics

    NASA Astrophysics Data System (ADS)

    Trancoso, R.

    2015-12-01

    The characteristics of streamflow reflect the co-evolution of climate, soils, topography and vegetation of catchments. Hydrological metrics or signatures can represent the long-term behaviour and integrate the influence of all the streamflow drivers. Although this sort of relationship has been developed in regional studies exploring prediction of Flow Duration Curves and other streamflow metrics, little is known about the controls of other key streamflow characteristics especially in continent scale. This study aims to understand how catchment biophysical variables control key hydrological metrics such as baseflow index, elasticity of streamflow to rainfall variability and intermittency in continent scale and regionally. We used a set of catchment biophysical variables to model key streamflow signatures using multivariate power-law and beta regressions in 355 catchments located along the eastern Australian seaboard. Streamflow signatures were derived from daily streamflow time series data from 1980 to 2013. We tested 52 catchment biophysical characteristics related to climate, soil, topography, geography, geomorphology, vegetation and land-cover as predictors of the streamflow signatures. The prediction R-squared ranged from 63 to 72% when relationships are built in continent scale, but can be greater than 80% when regressions are regionalised. The interpretation of the modelled relationships offers new insights regarding the controls of flow characteristics.

  15. Impact of improved snowmelt modelling in a monthly hydrological model.

    NASA Astrophysics Data System (ADS)

    Folton, Nathalie; Garcia, Florine

    2016-04-01

    The quantification and the management of water resources at the regional scale require hydrological models that are both easy to implement and efficient. To be reliable and robust, these models must be calibrated and validated on a large number of catchments that are representative of various hydro-meteorological conditions, physiographic contexts, and specific hydrological behavior (e.g. mountainous catchments). The GRLoiEau monthly model, with its simple structure and its two free parameters, answer our need of such a simple model. It required the development of a snow routine to model catchments with temporarily snow-covered areas. The snow routine developed here does not claim to represent physical snowmelt processes but rather to simulate them globally on the catchment. The snowmelt equation is based on the degree-day method which is widely used by the hydrological community, in particular in engineering studies (Etchevers 2000). A potential snowmelt (Schaefli et al. 2005) was computed, and the parameters of the snow routine were regionalized for each mountain area. The GRLoiEau parsimonious structure requires meteorological data. They come from the distributed mesoscale atmospheric analysis system SAFRAN, which provides estimations of daily solid and liquid precipitations and temperatures on a regular square grid at the spatial resolution of 8*8 km², throughout France. Potential evapotranspiration was estimated using the formula by Oudin et al. (2005). The aim of this study is to improve the quality of monthly simulations for ungauged basins, in particular for all types of mountain catchments, without increasing the number of free parameters of the model. By using daily SAFRAN data, the production store and snowmelt can be run at a daily time scale. The question then arises whether simulating the monthly flows using a production function at a finer time step would improve the results. And by using the SAFRAN distributed climate series, a distributed approach

  16. Seasonal and successional streamflow response to forest cutting and regrowth in the northwest and eastern United States

    NASA Astrophysics Data System (ADS)

    Jones, Julia A.; Post, David A.

    2004-05-01

    This study examined daily streamflow response over up to four decades in northwest conifer forest and eastern deciduous forest sites in the United States. We used novel methods to analyze daily observations of climate and streamflow spanning more than 900 basin years of record at 14 treated/control basin pairs where forest removal and regrowth experiments were underway in the period 1930-2002. In the 1 to 5-year period after forest removal, maximum daily increases ranged from 2 to 3 mm at deciduous forest sites, to 6 to 8 mm at conifer forest sites. Significant spring surpluses persisted for up to 35 years in conifer forest basins, but winter and spring streamflow deficits appeared after 10 to 15 years of forest regrowth in eastern deciduous forest basins. In all 5-yr posttreatment periods, absolute changes in daily streamflow were significantly more likely during moist, warm seasons, or during snowmelt seasons, but relative changes were more likely during warm seasons irrespective of moisture status. Both relative and absolute streamflow changes in the 1 to 5 and 15 to 25-year periods after forest removal were significantly positively related to the age of the forest at the time it was cut. Eastern deciduous forests had been disturbed by logging or hurricane 12 to 56 years prior to forest removal, while Pacific Northwest conifer forests had been not experienced logging or wildfire for 90 to 450 years. Paired basin experiments provide a continuous, and continuously changing, record of vegetation structure, composition, and climate, and their effects on streamflow.

  17. Influences of Main Large-Scale Climate Indices on Canada's Streamflow Trends over the Past Several Decades

    NASA Astrophysics Data System (ADS)

    Nalley, D.; Adamowski, J. F.; Biswas, A.; Khalil, B.

    2015-12-01

    The main objective of this study is to examine the influence of three important large-scale climate indices influencing the Canadian climate on Canada's monthly streamflow trends. These main climate indices are El-Niño Southern Oscillation (ENSO), the North Atlantic Oscillation (NAO), and Pacific Decadal Oscillation (PDO). This study combines the use of wavelet transform techniques and the Mann-Kendall (MK) trend test in order to achieve its main objective. The MK test was used to analyze trends and determine the starting point of trends in streamflow data. The continuous wavelet transform (CWT) was used to extract the time-frequency information of the streamflow and climate index data used. Only streamflow data from gauging stations that are categorized as natural and have a minimum of 40 years of complete records were used in the study - there are 73 gauging stations that met these requirements. Starting points of trends varied from station to station, and the CWT obtained show variabilities at the intra-annual, inter-annual and inter-decadal scales. Wavelet coherence spectra indicate that the influences of ENSO and the NAO indices occur at the 2-6-year time scales, and the influences of the PDO index are more apparent at time scales of up to 8 years and greater than 16 years. In particular, all CWT spectra of streamflow consistently show significant variability at the 6-12 months scales (which may be related to seasonality events such as spring snowmelt). The 6-12 month frequencies were isolated from the streamflow data and Spearman's correlation coefficients were used to identify the amount of time streamflow activities lagged behind the influence of each climate index. This study observed that dominant sources of streamflow variations at periodic scales of 6-12 months, are more significantly influenced by NAO and PDO indices compared with ENSO. The results obtained from this study can be used by water managers and planners in different regions of Canada to

  18. Streamflow Responses and Ecological Implications of Climate Change in New York City Water Supply Watershed

    NASA Astrophysics Data System (ADS)

    Pradhanang, S. M.; Mukundan, R.; Schneiderman, E.; Zion, M. S.; Swamy, A.; Pierson, D. C.; Frei, A.; Easton, Z. M.; Fuka, D. R.; Steenhuis, T. S.

    2011-12-01

    The impact of climate change in the North East United States is already observed in the form of shorter winter, higher annual average temperature, and more frequent extreme heat and precipitation events. These changes could have profound effects on the New York City (NYC) Water Supply and ecological integrity of the watersheds; and the implications of such changes are not well understood. The objective of this study is to examine how future changes in precipitation and air temperature may translate into changes in streamflow in the NYC Water Supply watershed using the Soil and Water Assessment Tool-Water Balance (SWAT-WB). A comparative analysis between simulated streamflow for baseline period (1964-2008) and future scenarios (2081-2100) was carried out for streamflow indicators that are important for understanding how river flow dynamics will impact the water supply, aquatic health, and physical structures in the stream corridor. We analyze the impacts of changes in the magnitude, timing, duration, frequency, and rate of hydrologic events using the Indicators of Hydrologic Alteration (IHA) tool. Our results indicate that warming during the winter and the early spring diminishes snowpack and influence timing of snowmelt. The winter and spring streamflow are projected to increase but summer will be drier in future. Decreased flow during April and summer months will influence timing of fish spawning and their habitats. Low flows, hydrograph pulses, rise and fall rates are expected to increase due to climate change, potentially creating unfavorable conditions for native species and aquatic invertebrates inhabiting along river's edge, and affecting stream bank stability and physical structures.

  19. Optimising seasonal streamflow forecast lead time for operational decision making in Australia

    NASA Astrophysics Data System (ADS)

    Schepen, Andrew; Zhao, Tongtiegang; Wang, Q. J.; Zhou, Senlin; Feikema, Paul

    2016-10-01

    Statistical seasonal forecasts of 3-month streamflow totals are released in Australia by the Bureau of Meteorology and updated on a monthly basis. The forecasts are often released in the second week of the forecast period, due to the onerous forecast production process. The current service relies on models built using data for complete calendar months, meaning the forecast production process cannot begin until the first day of the forecast period. Somehow, the bureau needs to transition to a service that provides forecasts before the beginning of the forecast period; timelier forecast release will become critical as sub-seasonal (monthly) forecasts are developed. Increasing the forecast lead time to one month ahead is not considered a viable option for Australian catchments that typically lack any predictability associated with snowmelt. The bureau's forecasts are built around Bayesian joint probability models that have antecedent streamflow, rainfall and climate indices as predictors. In this study, we adapt the modelling approach so that forecasts have any number of days of lead time. Daily streamflow and sea surface temperatures are used to develop predictors based on 28-day sliding windows. Forecasts are produced for 23 forecast locations with 0-14- and 21-day lead time. The forecasts are assessed in terms of continuous ranked probability score (CRPS) skill score and reliability metrics. CRPS skill scores, on average, reduce monotonically with increase in days of lead time, although both positive and negative differences are observed. Considering only skilful forecast locations, CRPS skill scores at 7-day lead time are reduced on average by 4 percentage points, with differences largely contained within +5 to -15 percentage points. A flexible forecasting system that allows for any number of days of lead time could benefit Australian seasonal streamflow forecast users by allowing more time for forecasts to be disseminated, comprehended and made use of prior to

  20. Levels at streamflow gaging stations

    USGS Publications Warehouse

    Kennedy, E.J.

    1990-01-01

    This manual establishes the surveying procedures for (1) setting gages at a streamflow gaging station to datum and (2) checking the gages periodically for errors caused by vertical movement of the structures that support them. Surveying terms and concepts are explained, and procedures for testing, adjusting, and operating the instruments are described in detail. Notekeeping, adjusting level circuits, checking gages, summarizing results, locating the nearest National Geodetic Vertical Datum of 1929 bench mark, and relating the gage datum to the national datum are also described.

  1. Taking the pulse of snowmelt: in situ sensors reveal seasonal, event and diurnal patterns of nitrate and dissolved organic matter variability in an upland forest stream

    USGS Publications Warehouse

    Pellerin, Brian A.; Saraceno, John Franco; Shanley, James B.; Sebestyen, Stephen D.; Aiken, George R.; Wollheim, Wilfred M.; Bergamaschi, Brian A.

    2011-01-01

    Highly resolved time series data are useful to accurately identify the timing, rate, and magnitude of solute transport in streams during hydrologically dynamic periods such as snowmelt. We used in situ optical sensors for nitrate (NO3-) and chromophoric dissolved organic matter fluorescence (FDOM) to measure surface water concentrations at 30 min intervals over the snowmelt period (March 21–May 13, 2009) at a 40.5 hectare forested watershed at Sleepers River, Vermont. We also collected discrete samples for laboratory absorbance and fluorescence as well as δ18O–NO3- isotopes to help interpret the drivers of variable NO3- and FDOM concentrations measured in situ. In situ data revealed seasonal, event and diurnal patterns associated with hydrological and biogeochemical processes regulating stream NO3- and FDOM concentrations. An observed decrease in NO3- concentrations after peak snowmelt runoff and muted response to spring rainfall was consistent with the flushing of a limited supply of NO3- (mainly from nitrification) from source areas in surficial soils. Stream FDOM concentrations were coupled with flow throughout the study period, suggesting a strong hydrologic control on DOM concentrations in the stream. However, higher FDOM concentrations per unit streamflow after snowmelt likely reflected a greater hydraulic connectivity of the stream to leachable DOM sources in upland soils. We also observed diurnal NO3- variability of 1–2 μmol l-1 after snowpack ablation, presumably due to in-stream uptake prior to leafout. A comparison of NO3- and dissolved organic carbon yields (DOC, measured by FDOM proxy) calculated from weekly discrete samples and in situ data sub-sampled daily resulted in small to moderate differences over the entire study period (-4 to 1% for NO3- and -3 to -14% for DOC), but resulted in much larger differences for daily yields (-66 to +27% for NO3- and -88 to +47% for DOC, respectively). Despite challenges inherent in in situ sensor

  2. Development of a Precipitation-Runoff Model to Simulate Unregulated Streamflow in the Salmon Creek Basin, Okanogan County, Washington

    USGS Publications Warehouse

    van Heeswijk, Marijke

    2006-01-01

    Surface water has been diverted from the Salmon Creek Basin for irrigation purposes since the early 1900s, when the Bureau of Reclamation built the Okanogan Project. Spring snowmelt runoff is stored in two reservoirs, Conconully Reservoir and Salmon Lake Reservoir, and gradually released during the growing season. As a result of the out-of-basin streamflow diversions, the lower 4.3 miles of Salmon Creek typically has been a dry creek bed for almost 100 years, except during the spring snowmelt season during years of high runoff. To continue meeting the water needs of irrigators but also leave water in lower Salmon Creek for fish passage and to help restore the natural ecosystem, changes are being considered in how the Okanogan Project is operated. This report documents development of a precipitation-runoff model for the Salmon Creek Basin that can be used to simulate daily unregulated streamflows. The precipitation-runoff model is a component of a Decision Support System (DSS) that includes a water-operations model the Bureau of Reclamation plans to develop to study the water resources of the Salmon Creek Basin. The DSS will be similar to the DSS that the Bureau of Reclamation and the U.S. Geological Survey developed previously for the Yakima River Basin in central southern Washington. The precipitation-runoff model was calibrated for water years 1950-89 and tested for water years 1990-96. The model was used to simulate daily streamflows that were aggregated on a monthly basis and calibrated against historical monthly streamflows for Salmon Creek at Conconully Dam. Additional calibration data were provided by the snowpack water-equivalent record for a SNOTEL station in the basin. Model input time series of daily precipitation and minimum and maximum air temperatures were based on data from climate stations in the study area. Historical records of unregulated streamflow for Salmon Creek at Conconully Dam do not exist for water years 1950-96. Instead, estimates of

  3. Rainfall and snow-melt triggered glacial lake outbursts: a systematic analysis of the Kedarnath (Uttarakhand, India), June 2013 disaster

    NASA Astrophysics Data System (ADS)

    Allen, Simon; Rastner, Philipp; Arora, Manohar; Huggel, Christian; Stoffel, Markus

    2015-04-01

    Heavy rainfall in early June 2013 triggered flash flooding and landslides throughout the Indian Himalayan state of Uttarakhand, killing more than 6000 people. The destruction of roads and trekking routes left around 100,000 pilgrims and tourists stranded. Most fatalities and damages resulted directly from a lake outburst and debris flow disaster originating from above the village of Kedarnath on June 16 and 17. Here we provide a first systematic analysis of the contributing factors leading to the Kedarnath disaster, both in terms of hydro-meteorological triggering (rainfall, snowmelt, and temperature) and topographic predisposition. Specifically, the topographic characteristics of the Charobari lake watershed above Kedarnath are compared with other glacial lakes across the northwestern Indian Himalayan states of Uttarakhand and Himachal Pradesh, and implications for glacier lake outburst hazard assessment in a changing climate are discussed. Our analysis suggests that the early onset of heavy monsoon rainfall (390 mm, June 10 - 17) immediately following a prolonged four week period of unusually rapid snow cover depletion and elevated streamflow is the crucial hydro-meteorological factor, resulting in slope saturation and significant runoff into the small seasonal glacial lake. Over a four week period the MODIS-derived snow covered area above Kedarnath decreased nearly 50%, from above average coverage in mid-May to well below average coverage by the second week of June. Such a rapid decrease has not been observed in the previous 13-year record, where the average decrease in snow covered area over the same four week window is only 15%. The unusual situation of the lake being dammed in a steep, unstable paraglacial environment, but fed entirely from snow-melt and rainfall within a fluvial dominated watershed is important in the context of this disaster. A simple scheme enabling large-scale recognition of such an unfavorable topographic setting is presented, and on the

  4. Contribution of MODIS Derived Snow Cover Satellite Data into Artificial Neural Network for Streamflow Estimation

    NASA Astrophysics Data System (ADS)

    Uysal, Gokcen; Arda Sorman, Ali; Sensoy, Aynur

    2014-05-01

    Contribution of snowmelt and correspondingly snow observations are highly important in mountainous basins for modelers who deal with conceptual, physical or soft computing models in terms of effective water resources management. Long term archived continuous data are needed for appropriate training and testing of data driven approaches like artificial neural networks (ANN). Data is scarce at the upper elevations due to the difficulty of installing sufficient automated SNOTEL stations; thus in literatures many attempts are made on the rainfall dominated basins for streamflow estimation studies. On the other hand, optical satellites can easily detect snow because of its high reflectance property. MODIS (Moderate Resolution Imaging Spectroradiometer) satellite that has two platforms (Terra and Aqua) provides daily and 8-daily snow images for different time periods since 2000, therefore snow cover data (SCA) may be useful as an input layer for ANN applications. In this study, a multi-layer perceptron (MLP) model is trained and tested with precipitation, temperature, radiation, previous day discharges as well as MODIS daily SCA data. The weights and biases are optimized with fastest and robust Levenberg-Marquardt backpropagation algorithm. MODIS snow cover images are removed from cloud coverage using certain filtering techniques. The Upper Euphrates River Basin in eastern part of Turkey (10 250 km2) is selected as the application area since it is fed by snowmelt approximately 2/3 of total annual volume during spring and early summer. Several input models and ANN structures are investigated to see the effect of the contributions using 10 years of data (2001-2010) for training and validation. The accuracy of the streamflow estimations is checked with statistical criteria (coefficient of determination, Nash-Sutcliffe model efficiency, root mean square error, mean absolute error) and the results seem to improve when SCA data is introduced. Furthermore, a forecast study is

  5. Importance of Wetlands to Streamflow Generation

    Treesearch

    E. S. Verry; R. K. Kolka

    2003-01-01

    Hewlett (1961) proposed the variable-source-area concept of streamflow origin in the mountains of North Carolina suggesting streamflow was produced from water leaving saturated areas near the channel. Dunne and Black confirmed this concept on the Sleepers River watershed in Vermont (1970). Areas near the river were saturated by subsurface or interflow from adjacent...

  6. Management of the Spring Snowmelt Recession in Regulated Systems

    NASA Astrophysics Data System (ADS)

    Yarnell, S. M.; Lind, A.; Epke, G.; Viers, J. H.

    2013-12-01

    In unregulated rivers in the Sierra Nevada mountains of California, the spring snowmelt recession links high winter flows to low summer baseflow and is a consistent and predictable portion of the annual hydrograph. Consequently, it is an important resource to both riverine ecosystems and California's water supply. In regulated river systems where the spring snowmelt recession is often captured behind dams or diverted for hydropower, restoration of a more natural spring flow regime can provide distinct ecological benefits, such as breeding and migration cues for native species, increased habitat availability, and greater hydraulic habitat diversity. However, knowledge of how to create and manage an ecologically beneficial spring snowmelt recession in a regulated river system has been lacking. This study defined a methodology by which spring flow regimes can be modeled in regulated systems from the quantifiable characteristics of spring snowmelt recessions in unregulated rivers. Using fundamental flow components such as magnitude, timing, and rate of change, the spring snowmelt recession in eight unregulated rivers across the Sierra Nevada range was quantified to gain a better understanding of the predictability and variability across watersheds. The analysis found that unregulated Sierran systems behaved similarly with respect to seasonal patterns and flow recession shape (i.e., recession limb curvature), and thus flows could be modeled in a manner that mimics those predictable characteristics. Using this methodology that quantifies spring recession flows in terms of a daily percent decrease in flow, a series of flow recession scenarios were then created for application on a regulated Sierran river. Four scenarios, ranging from a slow natural recession to a short fast recession typically observed in regulated rivers following cessation of high flow spills, were evaluated within a 2D hydrodynamic model. The effects of the flows on suitable habitat for Foothill yellow

  7. Low Streamflow Forcasting using Minimum Relative Entropy

    NASA Astrophysics Data System (ADS)

    Cui, H.; Singh, V. P.

    2013-12-01

    Minimum relative entropy spectral analysis is derived in this study, and applied to forecast streamflow time series. Proposed method extends the autocorrelation in the manner that the relative entropy of underlying process is minimized so that time series data can be forecasted. Different prior estimation, such as uniform, exponential and Gaussian assumption, is taken to estimate the spectral density depending on the autocorrelation structure. Seasonal and nonseasonal low streamflow series obtained from Colorado River (Texas) under draught condition is successfully forecasted using proposed method. Minimum relative entropy determines spectral of low streamflow series with higher resolution than conventional method. Forecasted streamflow is compared to the prediction using Burg's maximum entropy spectral analysis (MESA) and Configurational entropy. The advantage and disadvantage of each method in forecasting low streamflow is discussed.

  8. Improving daily streamflow forecasts in mountainous Upper Euphrates basin by multi-layer perceptron model with satellite snow products

    NASA Astrophysics Data System (ADS)

    Uysal, Gökçen; Şensoy, Aynur; Şorman, A. Arda

    2016-12-01

    This paper investigates the contribution of Moderate Resolution Imaging Spectroradiometer (MODIS) satellite Snow Cover Area (SCA) product and in-situ snow depth measurements to Artificial Neural Network model (ANN) based daily streamflow forecasting in a mountainous river basin. In order to represent non-linear structure of the snowmelt process, Multi-Layer Perceptron (MLP) Feed-Forward Backpropagation (FFBP) architecture is developed and applied in Upper Euphrates River Basin (10,275 km2) of Turkey where snowmelt constitutes approximately 2/3 of total annual volume of runoff during spring and early summer months. Snowmelt season is evaluated between March and July; 7 years (2002-2008) seasonal daily data are used during training while 3 years (2009-2011) seasonal daily data are split for forecasting. One of the fastest ANN training algorithms, the Levenberg-Marquardt, is used for optimization of the network weights and biases. The consistency of the network is checked with four performance criteria: coefficient of determination (R2), Nash-Sutcliffe model efficiency (ME), root mean square error (RMSE) and mean absolute error (MAE). According to the results, SCA observations provide useful information for developing of a neural network model to predict snowmelt runoff, whereas snow depth data alone are not sufficient. The highest performance is experienced when total daily precipitation, average air temperature data are combined with satellite snow cover data. The data preprocessing technique of Discrete Wavelet Analysis (DWA) is coupled with MLP modeling to further improve the runoff peak estimates. As a result, Nash-Sutcliffe model efficiency is increased from 0.52 to 0.81 for training and from 0.51 to 0.75 for forecasting. Moreover, the results are compared with that of a conceptual model, Snowmelt Runoff Model (SRM), application using SCA as an input. The importance and the main contribution of this study is to use of satellite snow products and data

  9. Streamflow forecasting using functional regression

    NASA Astrophysics Data System (ADS)

    Masselot, Pierre; Dabo-Niang, Sophie; Chebana, Fateh; Ouarda, Taha B. M. J.

    2016-07-01

    Streamflow, as a natural phenomenon, is continuous in time and so are the meteorological variables which influence its variability. In practice, it can be of interest to forecast the whole flow curve instead of points (daily or hourly). To this end, this paper introduces the functional linear models and adapts it to hydrological forecasting. More precisely, functional linear models are regression models based on curves instead of single values. They allow to consider the whole process instead of a limited number of time points or features. We apply these models to analyse the flow volume and the whole streamflow curve during a given period by using precipitations curves. The functional model is shown to lead to encouraging results. The potential of functional linear models to detect special features that would have been hard to see otherwise is pointed out. The functional model is also compared to the artificial neural network approach and the advantages and disadvantages of both models are discussed. Finally, future research directions involving the functional model in hydrology are presented.

  10. The Impact of Changing Snowmelt Timing on Non-Irrigated Crop Yield in Idaho

    NASA Astrophysics Data System (ADS)

    Murray, E. M.; Cobourn, K.; Flores, A. N.; Pierce, J. L.; Kunkel, M. L.

    2013-12-01

    The impacts of climate change on water resources have implications for both agricultural production and grower welfare. Many mountainous regions in the western U.S. rely on snowmelt as the dominant surface water source, and in Idaho, reconstructions of spring snowmelt timing have demonstrated a trend toward earlier, more variable snowmelt dates within the past 20 years. This earlier date and increased variability in snowmelt timing have serious implications for agriculture, but there is considerable uncertainty about how agricultural impacts vary by region, crop-type, and practices like irrigation vs. dryland farming. Establishing the relationship between snowmelt timing and agricultural yield is important for understanding how changes in large-scale climatic indices (like snowmelt date) may be associated with changes in agricultural yield. This is particularly important where local practitioner behavior is influenced by historically observed relationships between these climate indices and yield. In addition, a better understanding of the influence of changes in snowmelt on non-irrigated crop yield may be extrapolated to better understand how climate change may alter biomass production in non-managed ecosystems. To investigate the impact of snowmelt date on non-irrigated crop yield, we developed a multiple linear regression model to predict historical wheat and barley yield in several Idaho counties as a function of snowmelt date, climate variables (precipitation and growing degree-days), and spatial differences between counties. The relationship between snowmelt timing and non-irrigated crop yield at the county level is strong in many of the models, but differs in magnitude and direction for the two different crops. Results show interesting spatial patterns of variability in the correlation between snowmelt timing and crop yield. In four southern counties that border the Snake River Plain and one county bordering Oregon, non-irrigated wheat and/or barley yield are

  11. A mixture of heavy rainfall, snowmelt, and ice

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Credit: Image courtesy Jacques Descloitres, MODIS Land Rapid Response Team at NASA GSFC Satellite: Terra Sensor: MODIS Image Date: 06-16-2002 VE Record ID: 13692 Description: A mixture of heavy rainfall, snowmelt, and ice jams in late May and early June of this year caused the Ob River and surrounding tributaries in Western Siberia to overflow their banks. The flooding can be seen in this image taken on June 16, 2002, by the MODIS (Moderate Resolution Imaging Spectroradiometer) instrument aboard the Terra satellite. Last year, the river flooded farther north. Normally, the river resembles a thin black line.

  12. A Synopsis and Comparison of Selected Snowmelt Algorithms

    DTIC Science & Technology

    1999-07-01

    temperature. (U.S. Army 1956). If humidity data are unavail- When Tp is < 0°C, the meltwater or rain is refro- able, Em is estimated. On days with...iso- During convective storms, Em is computed sepa- thermal, the meltwater is first used to satisfy the rately for each 12-hr period as a function of...layer evo- 8 .Return to contents lution during summer snowmelt on the Greenland water flow scheme is coupled to the equilibrium ice sheet (Rowe et al

  13. Streamflow alteration at selected sites in Kansas

    USGS Publications Warehouse

    Juracek, Kyle E.; Eng, Ken

    2017-06-26

    An understanding of streamflow alteration in response to various disturbances is necessary for the effective management of stream habitat for a variety of species in Kansas. Streamflow alteration can have negative ecological effects. Using a modeling approach, streamflow alteration was assessed for 129 selected U.S. Geological Survey streamgages in the State for which requisite streamflow and basin-characteristic information was available. The assessment involved a comparison of the observed condition from 1980 to 2015 with the predicted expected (least-disturbed) condition for 29 streamflow metrics. The metrics represent various characteristics of streamflow including average flow (annual, monthly) and low and high flow (frequency, duration, magnitude).Streamflow alteration in Kansas was indicated locally, regionally, and statewide. Given the absence of a pronounced trend in annual precipitation in Kansas, a precipitation-related explanation for streamflow alteration was not supported. Thus, the likely explanation for streamflow alteration was human activity. Locally, a flashier flow regime (typified by shorter lag times and more frequent and higher peak discharges) was indicated for three streamgages with urbanized basins that had higher percentages of impervious surfaces than other basins in the State. The combination of localized reservoir effects and regional groundwater pumping from the High Plains aquifer likely was responsible, in part, for diminished conditions indicated for multiple streamflow metrics in western and central Kansas. Statewide, the implementation of agricultural land-management practices to reduce runoff may have been responsible, in part, for a diminished duration and magnitude of high flows. In central and eastern Kansas, implemented agricultural land-management practices may have been partly responsible for an inflated magnitude of low flows at several sites.

  14. A Method of Streamflow Drought Analysis

    NASA Astrophysics Data System (ADS)

    Zelenhasić, Emir; Salvai, Atila

    1987-01-01

    A method of completely describing and analyzing the stochastic process of streamflow droughts has been recommended. All important components of streamflow droughts such as deficit, duration, time of occurrence, number of streamflow droughts in a given time interval [0, t], the largest streamflow drought deficit, and the largest streamflow drought duration in a given time interval [0, t] are taken into consideration. A streamflow drought is related here to streamflow deficit. Following the theory of the supremum of a random number of random variables a stochastic model is presented for interpretation and analysis of the largest streamflow drought deficit below a given reference discharge and the largest streamflow drought duration concerning a time interval [0, t], at a given location of a river. The method is based on the assumption that streamflow droughts are independent, identically distributed random variables and that their occurrence is subject to the Poisson probability law. This paper is actually a continuation of the previous E. Zelenhasić (1970, 1979, 1983) and P. Todorović (1970) works on the extremes in hydrology. Application of the method is made on the 58-year record of the Sava River at Sr. Mitrovica and on the 52-year record of Tisa River at Senta, Yugoslavia, and good agreement is found between the theoretical and empirical distribution functions for all analyzed drought components for both rivers. Only one complete example, the Sava River at Sr. Mitrovica, is given in the paper. The proposed method deals with hydrograph recessions of daily or instantaneous discharges in the region of low flows, and not with mean annual flows which were used by other investigators.

  15. Grassed swales for stormwater pollution control during rain and snowmelt.

    PubMed

    Bäckström, M

    2003-01-01

    The retention of suspended solids, particles and heavy metals in different grassed swales during rain events and snowmelt is discussed. The experimental results derived from investigations performed in existing grassed swales in the Luleå region, Northern Sweden. During high pollutant loading rates, grassed swales retain significant amounts of pollutants, mainly due to sedimentation of particulate matter. Low to moderate removal efficiencies could be expected for heavy metals, especially metals in solution (i.e. the dissolved phase). When grassed swales receive urban runoff with low pollutant concentrations, they may release rather than retain pollutants. Swales are important snow deposit areas in the city and particle bound pollutants do to a large extent remain in the swale after snowmelt. However, dissolved pollutants (i.e. dissolved heavy metals) are likely to escape the swale with the melt water. Grassed swales may be regarded as facilities that even out the peaks in pollutant loads without being capable of producing consistent high removal rates. This suggests that swales should be considered as primary treatment devices. Possible design parameters for grassed swales are mean hydraulic detention time, surface loading rate or specific swale area.

  16. Monitoring Water Resources Status with Distributed Snowmelt Model

    NASA Astrophysics Data System (ADS)

    Artan, G.; Dwyer, J.; Verdin, J.; Budde, M.

    2005-12-01

    A large amount of the Afghanistan water supply comes from reservoirs fed by snowmelt runoff, therefore, monitoring the status of snow cover in key areas during the winter and spring is very import to the water resources and disaster management entities of the country. In this study we investigated the utility of monitoring the status of the snow over Afghanistan by employing a spatially distributed snow accumulation and ablation model forced solely with remotely sensed data, weather model assimilation fields, and globally available near-real time meteorological data. The snowmelt model we used was a spatially distributed version of the Utah Energy Balance (UEB) model. A fundamental input variable that went into the model was a dynamic MODIS-based albedo. The MODIS-based snow albedo we used was an integrated 8-days running average value calculated for areas that were established to be cloud-free by the MODIS cloud mask and snow covered by the MODIS snow algorithm (Klein and Stroeve, 2002). The modeled spatial distribution of snow water equivalent provided a good early indication of the relative magnitude of the water available in spring of 2005 for irrigation. The modeled snow water maps were also useful in mapping of basins that were likely to experience a higher risk for floods after the spring snow melts.

  17. Phenology is plastic: the response of alpine shrub Salix herbacea to earlier snowmelt

    NASA Astrophysics Data System (ADS)

    Wheeler, Julia; Sedlacek, Janosch; van Kleunen, Mark; Bossdorf, Oliver; Hoch, Guenter; Wipf, Sonja; Karrenberg, Sophie; Lexer, Christian; Cortés, Andres; Rixen, Christian

    2014-05-01

    Climate change has been demonstrated to accelerate snowmelt in alpine systems, which can represent a critical ecosystem change for alpine plant communities. Understanding how snowmelt timing affects phenology and the development of alpine plants, and the capacity of these plants to respond, is thus necessary for predicting alpine community response to climate change. We examined the effects of snowmelt timing on the phenological development of the common clonal alpine shrub Salix herbacea over three growing seasons using both a space-for-time substitution along a natural snowmelt gradient and a reciprocal transplant experiment of clonal fragments between early and late snowmelt microhabitats. Leaf, flower and fruit development time was significantly influenced by snowmelt timing along both the natural snow gradient and in the reciprocal transplant, with less time required to develop to each phenophase in shrubs growing naturally in late-lying snowbeds and in S. herbacea clonal fragments transplanted from early-exposure sites into late snowbed microhabitats. This suggests that snowmelt timing, likely through the regulation of seasonal temperature accumulation, controls phenological development. In addition, the transplant experiment indicated that S. herbacea demonstrates a highly plastic phenological response to snowmelt timing, because there was no significant difference in phenology between clones originating either from snowbeds or early exposure sites when exposed to the same climatic conditions. Thus, S. herbacea may be able to profit from accelerated snowmelt due to climate change by developing soon after snowmelt. However, freezing damage during vulnerable early development stages may increase, as phenological development is slowed and the probability of lethal freezing events is increased under early snowmelt conditions.

  18. Dendrochronology and links to streamflow

    NASA Astrophysics Data System (ADS)

    Meko, D. M.; Woodhouse, C. A.; Morino, K.

    2012-01-01

    SummaryStreamflow variability on timescales of decades to centuries becomes increasingly important as water managers grapple with shortages imposed by increasing demand and limited supply, and possibly exacerbated by climate change. Two applications of dendrochronology to the study of flow variability are illustrated for an existing 1244-yr reconstruction of annual flows of the Colorado River at Lees Ferry, Arizona, USA: (1) identification and climatological interpretation of rare flow events, and (2) assessment of vulnerability of water-supply systems to climatic variability. Analysis centers on a sustained drought of the mid-1100s characterized by persistent low flows on both the Colorado and Sacramento Rivers. Analysis of geopotential height anomalies during modern joint-droughts suggests more than one mode of circulation might accompany joint-drought in the two basins. Monte Carlo simulation is used to demonstrate that a drought as severe as that in the 1100s on the Colorado River might be expected about once in every 4-6 centuries by chance alone given the time-series properties of the modern gaged flows. Application of a river-management model suggests a mid-1100s-style drought, were it to occur today, would drop reservoir levels in Lake Mead to dead-pool within a few decades. Uncertainty presents challenges to accurately quantifying severe sustained droughts from streamflow reconstructions, especially early in the tree-ring record. Corroboration by multiple proxy records is essential. Future improvements are likely to require a combination of methodological advancements and expanded basic data.

  19. Remote sensing of drivers of spring snowmelt flooding in the North Central US

    USDA-ARS?s Scientific Manuscript database

    Spring snowmelt poses an annual flood risk in non-mountainous regions, such as the northern Great Plains of North America. However, ground observations are often not sufficient to characterize the spatiotemporal variation of drivers of snowmelt floods for operational flood forecasting purposes. Re...

  20. Hydrologic landscape classification evaluates streamflow vulnerability to climate change in Oregon, USA

    NASA Astrophysics Data System (ADS)

    Leibowitz, S. G.; Comeleo, R. L.; Wigington, P. J., Jr.; Weaver, C. P.; Morefield, P. E.; Sproles, E. A.; Ebersole, J. L.

    2014-09-01

    Classification can allow for evaluations of the hydrologic functions of landscapes and their responses to stressors. Here we demonstrate the use of a hydrologic landscape (HL) approach to evaluate vulnerability to potential future climate change at statewide and basin scales in the state of Oregon. The HL classification has five components: climate, seasonality, aquifer permeability, terrain, and soil permeability. We evaluate changes when the 1971-2000 HL climate indices are recalculated using 2041-2070 simulation results from the ECHAM (European Centre HAMburg) and PCM (Parallel Climate Model) climate models with the A2, A1b, and B1 emission scenarios. Changes in climate class were modest (4-18%) statewide. However, there were major changes in seasonality class for five of the six realizations (excluding PCM_B1): Oregon shifts from being 13% snow-dominated to 4-6% snow-dominated under these five realizations, representing a 56-68% reduction in snowmelt-dominated area. At the basin scale, simulated changes for the Siletz Basin, in Oregon's Coast Range, include a small switch from very wet to wet climate, with no change in seasonality. However, there is a modest increase in fall and winter water due to increased precipitation. For the Sandy Basin, on the western slope of the Cascades, HL climate class does not change, but there are major changes in seasonality, especially for areas with low aquifer permeability, which experiences a 100% loss of spring seasonality. This would reduce summer baseflow, but effects could potentially be mitigated by streamflow buffering effects provided by groundwater in the high aquifer permeability portions of the upper Sandy. The Middle Fork John Day Basin (MFJD), in northeastern Oregon, is snowmelt-dominated. The basin experiences a net loss of wet and moist climate area, along with an increase in dry climate area. The MFJD also experiences major shifts from spring to winter seasonality, representing a 20-60% reduction in snowmelt

  1. Hydrologic landscape classification assesses streamflow vulnerability to climate change in Oregon, USA

    NASA Astrophysics Data System (ADS)

    Leibowitz, S. G.; Comeleo, R. L.; Wigington, P. J., Jr.; Weaver, C. P.; Morefield, P. E.; Sproles, E. A.; Ebersole, J. L.

    2014-03-01

    Classification can allow assessments of the hydrologic functions of landscapes and their responses to stressors. Here we demonstrate the use of a hydrologic landscape (HL) approach to assess vulnerability to potential future climate change at statewide and basin scales. The HL classification has five components: climate, seasonality, aquifer permeability, terrain, and soil permeability. We evaluate changes when the 1971-2000 HL climate indices are recalculated using 2041-2070 simulation results from the ECHAM and PCM climate models with the A2, A1b, and B1 emission scenarios. Changes in climate class were modest (4-18%) statewide. However, there were major changes in seasonality class for five of the six realizations (excluding PCM_B1): Oregon shifts from being 13% snow-dominated to 4-6% snow-dominated under these five realizations, representing a 56-68% reduction in snowmelt-dominated area. At the basin scale, projected changes for the Siletz basin, in Oregon's coast range, include a small switch from very wet to wet climate, with no change in seasonality. However, there is a modest increase in fall and winter water due to increased precipitation. For the Sandy basin, on the western slope of the Cascades, HL climate class does not change, but there are major changes in seasonality, especially for areas with low aquifer permeability, which experiences a 100% loss of spring seasonality. This would reduce summer baseflow, but impacts could potentially be mitigated by streamflow buffering effects provided by groundwater in the high aquifer permeability portions of the upper Sandy. The Middle Fork John Day basin (MFJD), in northeastern Oregon, is snowmelt-dominated. The basin experiences a net loss of wet and moist climate area, along with an increase in dry climate area. The MFJD also experiences major shifts from spring to winter seasonality, representing a 20-60% reduction in snowmelt-dominated area. Altered seasonality and/or magnitude of seasonal streamflows could

  2. Snowmelt onset hinders bromine monoxide heterogeneous recycling in the Arctic

    NASA Astrophysics Data System (ADS)

    Burd, Justine A.; Peterson, Peter K.; Nghiem, Son V.; Perovich, Don K.; Simpson, William R.

    2017-08-01

    Reactive bromine radicals (bromine atoms, Br, and bromine monoxide, BrO) deplete ozone and alter tropospheric oxidation chemistry during the Arctic springtime (February-June). As spring transitions to summer (May-June) and snow begins to melt, reactive bromine events cease and BrO becomes low in summer. In this study, we explore the relationship between the end of the reactive bromine season and snowmelt timing. BrO was measured by Multi-AXis Differential Optical Absorption Spectrometer at Utqiaġvik (Barrow), AK, from 2012 to 2016 and on drifting buoys deployed in Arctic sea ice from 2011 to 2016, a total of 13 site and year combinations. The BrO seasonal end date (SED) was objectively determined and was compared to surface-air-temperature-derived melt onset date (MOD). The SED was highly correlated with the MOD (N = 13, R2 = 0.983, RMS = 1.9 days), and BrO is only observed at subfreezing temperatures. In subsets of these sites and years where ancillary data were available, we observed that snowpack depth reduced and rain precipitation occurred within a few days of the SED. These data are consistent with snowpack melting hindering BrO recycling, which is necessary to maintain enhanced BrO concentrations. With a projected warmer Arctic, a shift to earlier snowmelt seasons could alter the timing and role of halogen chemical reactions in the Arctic with impacts on ozone depletion and mercury deposition.Plain Language SummaryReactive bromine events in the Arctic are common in spring and deplete ozone and cause mercury deposition. These events are affected by snow and ice, which are changing in the Arctic; therefore, we need to understand how environmental conditions affect reactive bromine chemistry. We find that the reactive bromine season ends when snowpack begins to melt. Through these full seasonal observations, we find that reactive bromine events occur to warmer temperatures than previously reported</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1990JHyd..120...79W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1990JHyd..120...79W"><span>Annual and seasonal fluctuations of precipitation and <span class="hlt">streamflow</span> in the Aconcagua River basin, Chile</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Waylen, Peter R.; Caviedes, César N.</p> <p>1990-12-01</p> <p>The El Niño-Southern Oscillation (ENSO) phenomenon has been shown to influence dramatically precipitation and <span class="hlt">streamflow</span> in tropical western South America. The statistical properties of annual and winter precipitation totals and <span class="hlt">streamflow</span> characteristics in the Aconcagua River basin, in temperate central Chile, are investigated in such a way as to permit the identification of flood- and drought-generating processes and their possible linkages to upset behavior in the tropical Pacific. Despite the considerable distance to those regions generally associated with ENSO events, the phenomenon produces marked effects upon the various physical processes which govern the surface hydrometeorology of the study area. El Niño years result in significant increases in annual and winter precipitation, particularly along the coastal margin. The likelihood of rain or rain-on-snow flooding, in the succeeding winter, increases, as does the size of spring <span class="hlt">snowmelt</span> in the southern summer, 1 year after the upset conditions in the tropical region. Annual low flows are of higher magnitude and occur earlier in the year than is usual.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..17.4329Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..17.4329Y"><span>Climate change and probabilistic scenario of <span class="hlt">streamflow</span> extremes in a cryospheric alpine region</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yang, Tao; Gao, Cheng</p> <p>2015-04-01</p> <p>Future projections of <span class="hlt">streamflow</span> extremes are of paramount significance in assessing the climate impacts on social and natural systems, particularly for the Himalayan alpine region in the Tibetan Plateau known as the Asian Water Tower. This study strives to quantify the uncertainties from different sources in simulating future extreme flows and seeks to construct reliable scenarios of future extreme flows for the headwater catchment of the Yellow River Basin in the 21st century. The results can be formulated as follows: (1) The revised snow model based on a daily active temperature method is superior to the commonly used degree-day method in simulating <span class="hlt">snowmelt</span> processes. (2) In general, hydrological models contribute more uncertainties than the downscaling methods in high flow and low flow over the cryospheric alpine regions characterized by the snow-rainfall induced runoff processes under most scenarios. Meanwhile, impacts to uncertainty vary with time. (3) The ultimate probability of high-flow exhibits a downward trend in future by using an unconditional method, whereas positive changes in probability of low-flow are projected. The method in the work includes a variety of influence from different contributing factors (e.g. downscaling models, hydrological models, model parameters, and their simulation skills) on <span class="hlt">streamflow</span> projection, therefore can offer more information (i.e. different percentiles of flow and uncertainty ranges) for future water resources planning compared with the purely deterministic approaches. Hence, the results are beneficial to boost our current methodologies of climate impact research in the Himalayan alpine zone.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014JGRD..119.8535Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014JGRD..119.8535Y"><span>Climate change and probabilistic scenario of <span class="hlt">streamflow</span> extremes in an alpine region</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yang, Tao; Wang, Xiaoyan; Yu, Zhongbo; Krysanova, Valentina; Chen, Xi; Schwartz, Franklin W.; Sudicky, Edward A.</p> <p>2014-07-01</p> <p>Future projections of <span class="hlt">streamflow</span> extremes are of paramount significance in assessing the climate impacts on social and natural systems, particularly for the Himalayan alpine region in the Tibetan Plateau known as the Asian water tower. This study strives to quantify the uncertainties from different sources in simulating future extreme flows and seeks to construct reliable scenarios of future extreme flows for the headwater catchment of the Yellow River Basin in the 21st century. The results can be formulated as follows: (1) The revised snow model based on a daily active temperature method is superior to the commonly used degree-day method in simulating <span class="hlt">snowmelt</span> processes. (2) In general, hydrological models contribute more uncertainties than the downscaling methods in high flow and low flow over the cryospheric alpine regions characterized by the snow-rainfall-induced runoff processes under most scenarios. Meanwhile, impacts to uncertainty vary with time. (3) The ultimate probability of high flow exhibits a downward trend in future by using an unconditional method, whereas positive changes in the probability of low flow are projected. The method in the work includes a variety of influence from different contributing factors (e.g., downscaling models, hydrological models, model parameters, and their simulation skills) on <span class="hlt">streamflow</span> projection, therefore can offer more information (i.e., different percentiles of flow and uncertainty ranges) for future water resource planning compared with the purely deterministic approaches. Hence, the results are beneficial to boost our current methodologies of climate impact research in the Himalayan alpine zone.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/1052939','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/1052939"><span>The contribution of glacier melt to <span class="hlt">streamflow</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Schaner, Neil; Voisin, Nathalie; Nijssen, Bart; Lettenmaier, D. P.</p> <p>2012-09-13</p> <p>Ongoing and projected future changes in glacier extent and water storage globally have lead to concerns about the implications for water supplies. However, the current magnitude of glacier contributions to river runoff is not well known, nor is the population at risk to future glacier changes. We estimate an upper bound on glacier melt contribution to seasonal <span class="hlt">streamflow</span> by computing the energy balance of glaciers globally. Melt water quantities are computed as a fraction of total <span class="hlt">streamflow</span> simulated using a hydrology model and the melt fraction is tracked down the stream network. In general, our estimates of the glacier melt contribution to <span class="hlt">streamflow</span> are lower than previously published values. Nonetheless, we find that globally an estimated 225 (36) million people live in river basins where maximum seasonal glacier melt contributes at least 10% (25%) of <span class="hlt">streamflow</span>, mostly in the High Asia region.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.usgs.gov/fs/2009/3020/','USGSPUBS'); return false;" href="https://pubs.usgs.gov/fs/2009/3020/"><span>National <span class="hlt">Streamflow</span> Information Program: Implementation Status Report</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Norris, J. Michael</p> <p>2009-01-01</p> <p>The U.S. Geological Survey (USGS) operates and maintains a nationwide network of about 7,500 streamgages designed to provide and interpret long-term, accurate, and unbiased <span class="hlt">streamflow</span> information to meet the multiple needs of many diverse national, regional, state, and local users. The National <span class="hlt">Streamflow</span> Information Program (NSIP) was initiated in 2003 in response to Congressional and stakeholder concerns about (1) the decrease in the number of operating streamgages, including a disproportionate loss of streamgages with a long period of record; (2) the inability of the USGS to continue operating high-priority streamgages in an environment of reduced funding through partnerships; and (3) the increasing demand for <span class="hlt">streamflow</span> information due to emerging resource-management issues and new data-delivery capabilities. The NSIP's mission is to provide the <span class="hlt">streamflow</span> information and understanding required to meet national, regional, state, and local needs. Most of the existing streamgages are funded through partnerships with more than 850 other Federal, state, tribal, and local agencies. Currently, about 90 percent of the streamgages send data to the World Wide Web in near-real time (some information is transmitted within 15 minutes, whereas some lags by about 4 hours). The <span class="hlt">streamflow</span> information collected at USGS streamgages is used for many purposes: *In water-resource appraisals and allocations - to determine how much water is available and how it is being allocated; *To provide <span class="hlt">streamflow</span> information required by interstate agreements, compacts, and court decrees; *For engineering design of reservoirs, bridges, roads, culverts, and treatment plants; *For the operation of reservoirs, the operation of locks and dams for navigation purposes, and power production; *To identify changes in <span class="hlt">streamflow</span> resulting from changes in land use, water use, and climate; *For <span class="hlt">streamflow</span> forecasting, flood planning, and flood forecasting; *To support water-quality programs by allowing</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/263570','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/263570"><span>Clouds and <span class="hlt">snowmelt</span> on the north slope of Alaska</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Zhang, T.; Stamnes, K.; Bowling, S.A.</p> <p>1996-04-01</p> <p>Clouds have a large effect on the radiation field. Consequently, possible changes in cloud properties may have a very substantial impact on climate. Of all natural surfaces, seasonal snow cover has the highest surface albedo, which is one of the most important components of the climatic system. Interactions between clouds and seasonal snow cover are expected to have a significant effect on climate and its change at high latitudes. The purpose of this paper is to investigate the sensitivity of the surface cloud-radiative forcing during the period of <span class="hlt">snowmelt</span> at high latitudes. The primary variables investigated are cloud liquid path (LWP) and droplet equivalent radius (r{sub e}). We will also examine the sensitivity of the surface radiative fluxes to cloud base height and cloud base temperature.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.water.usgs.gov/sir2004-5202/','USGSPUBS'); return false;" href="http://pubs.water.usgs.gov/sir2004-5202/"><span>Precipitation-runoff processes in the Feather River basin, northeastern California, and <span class="hlt">streamflow</span> predictability, water years 1971-97</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Koczot, Kathryn M.; Jeton, Anne E.; McGurk, Bruce; Dettinger, Michael D.</p> <p>2005-01-01</p> <p>-shadowed basins of the northeastern Sierra Nevada than the uplands of most western Sierra Nevada river basins. The climate is mediterranean, with most of the annual precipitation occurring in winter. Because the basin includes large areas that are near the average snowline, rainfall and rain-snow mixtures are common during winter storms. Consequently, the overall timing and rates of runoff from the basin are highly sensitive to winter temperature fluctuations. The models were developed to simulate runoff-generating processes in eight drainages of the Feather River Basin. Together, these models simulate <span class="hlt">streamflow</span> from 98 percent of the basin above Lake Oroville. The models simulate daily water and heat balances, snowpack evolution and <span class="hlt">snowmelt</span>, evaporation and transpiration, subsurface water storage and outflows, and <span class="hlt">streamflow</span> to key <span class="hlt">streamflow</span> gage sites. The drainages are modeled as 324 hydrologic-response units, each of which is assumed homogeneous in physical characteristics and response to precipitation and runoff. The models were calibrated with emphasis on reproducing monthly <span class="hlt">streamflow</span> rates, and model simulations were compared to the total natural inflows into Lake Oroville as reconstructed by the California Department of Water Resources for April-July <span class="hlt">snowmelt</span> seasons from 1971 to 1997. The models are most sensitive to input values and patterns of precipitation and soil characteristics. The input precipitation values were allowed to vary on a daily basis to reflect available observations by making daily transformations to an existing map of long-term mean monthly precipitation rates that account for altitude and rain-shadow effects. The models effectively simulate <span class="hlt">streamflow</span> into Lake Oroville during water years (October through September) 1971-97, which is demonstrated in hydrographs and statistical results presented in this report. The Butt Creek model yields the most accurate historical April-July simulations, whereas the West Branch</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.H51O0813H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.H51O0813H"><span>Estimating Watershed-Averaged Precipitation and Evapotranspiration Fluxes using <span class="hlt">Streamflow</span> Measurements in a Semi-Arid, High Altitude Montane Catchment</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Herrington, C.; Gonzalez-Pinzon, R.</p> <p>2014-12-01</p> <p><span class="hlt">Streamflow</span> through the Middle Rio Grande Valley is largely driven by <span class="hlt">snowmelt</span> pulses and monsoonal precipitation events originating in the mountain highlands of New Mexico (NM) and Colorado. Water managers rely on results from storage/runoff models to distribute this resource statewide and to allocate compact deliveries to Texas under the Rio Grande Compact agreement. Prevalent drought conditions and the added uncertainty of climate change effects in the American southwest have led to a greater call for accuracy in storage model parameter inputs. While precipitation and evapotranspiration measurements are subject to scaling and representativeness errors, <span class="hlt">streamflow</span> readings remain relatively dependable and allow watershed-average water budget estimates. Our study seeks to show that by "Doing Hydrology Backwards" we can effectively estimate watershed-average precipitation and evapotranspiration fluxes in semi-arid landscapes of NM using fluctuations in <span class="hlt">streamflow</span> data alone. We tested this method in the Valles Caldera National Preserve (VCNP) in the Jemez Mountains of central NM. This method will be further verified by using existing weather stations and eddy-covariance towers within the VCNP to obtain measured values to compare against our model results. This study contributes to further validate this technique as being successful in humid and semi-arid catchments as the method has already been verified as effective in the former setting.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/22518','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/22518"><span>A proposed <span class="hlt">streamflow</span> data program for Oklahoma</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Bohn, J.D.; Hoffman, G.L.</p> <p>1970-01-01</p> <p>An evaluation of the <span class="hlt">streamflow</span> data available in Oklahoma has been made to provide guidelines for planning future data-collection programs. The basic steps in the evaluation procedure were (1) definition of the long-terms goals of the <span class="hlt">streamflow</span>-data program in quantitative form, (2) examination and analysis of <span class="hlt">streamflow</span> data to determine which goals have been met, and (3) consideration of alternate programs and techniques to meet the remaining goals. The study defines the individual relation between certain statistical <span class="hlt">streamflow</span> characteristics and selected basin parameters. This relation is a multiple regression equation that could be used on a statewide basis to compute a selected natural-flow characteristic at any site on a stream. The study shows that several <span class="hlt">streamflow</span> characteristics can be estimated within an accuracy equivalent to 10 years of record by use of a regression related to at least three climatic or basin parameters for any basin of 50 square miles or more. The study indicates that significant changes in the scope and character of the data-collection program would enhance the possibility of attaining the remaining goals. A <span class="hlt">streamflow</span>-data program based on the guidelines developed in this study is proposed for the future.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JHyd..521....1C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JHyd..521....1C"><span>Configurational entropy theory for <span class="hlt">streamflow</span> forecasting</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cui, Huijuan; Singh, Vijay P.</p> <p>2015-02-01</p> <p>This study develops configurational entropy theory (CET) for monthly <span class="hlt">streamflow</span> forecasting. The theory is comprised of three main parts: (1) determination of spectral density (2) determination of parameters by cepstrum analysis, and (3) extension of autocorrelation function. Comparison with the Burg entropy theory (BET) shows that CET yields higher resolution spectral density with more accurate location of spectral peaks. Cepstrum analysis yields more accurate parameters than the Levinson algorithm in the autoregressive (AR) method and the Levinson-Burg algorithm in BET. CET is tested using monthly <span class="hlt">streamflow</span> data from 19 river basins covering a broad range of physiographic characteristics. Testing shows that CET captures <span class="hlt">streamflow</span> seasonality and satisfactorily forecasts both high and low flows. High flows are satisfactorily forecasted with the coefficient of determination (r2) higher than 0.92 for one year ahead of time, with r2 higher than 0.85 for two years ahead of time, and up to 60 months ahead with r2 higher than 0.80. However, low flows are forecasted with r2 higher than 0.50 for one year ahead time. When relative drainage area is considered for analyzing <span class="hlt">streamflow</span> characteristics and spectral patterns, it is found that upstream <span class="hlt">streamflow</span> is forecasted more accurately (r2 = 0.84) than downstream <span class="hlt">streamflow</span> (r2 = 0.75). Residuals of forecasted values relative to observed values are found to follow normal distribution.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ars.usda.gov/research/publications/publication/?seqNo115=286355','TEKTRAN'); return false;" href="http://www.ars.usda.gov/research/publications/publication/?seqNo115=286355"><span>Using the <span class="hlt">snowmelt</span> runoff model to evaluate climate change effects and to compare basin runoff between New Mexico and Idaho.</span></a></p> <p><a target="_blank" href="https://www.ars.usda.gov/research/publications/find-a-publication/">USDA-ARS?s Scientific Manuscript database</a></p> <p></p> <p></p> <p>The <span class="hlt">Snowmelt</span> Runoff Model(SRM) has been developed and tested in small to large basins worldwide. SRM has been found to be very useful for understanding <span class="hlt">snowmelt</span> processes as well as for simulating or forecasting <span class="hlt">snowmelt</span>-derived water supplies. SRM is being used in New Mexico in a NSF-funded EPSCo...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.fs.usda.gov/treesearch/pubs/36968','TREESEARCH'); return false;" href="https://www.fs.usda.gov/treesearch/pubs/36968"><span>Improvement of distributed <span class="hlt">snowmelt</span> energy balance modeling with MODIS-based NDSI-derived fractional snow-covered area data</span></a></p> <p><a target="_blank" href="http://www.fs.usda.gov/treesearch/">Treesearch</a></p> <p>Joel W. Homan; Charles H. Luce; James P. McNamara; Nancy F. Glenn</p> <p>2011-01-01</p> <p>Describing the spatial variability of heterogeneous snowpacks at a watershed or mountain-front scale is important for improvements in large-scale <span class="hlt">snowmelt</span> modelling. <span class="hlt">Snowmelt</span> depletion curves, which relate fractional decreases in snowcovered area (SCA) against normalized decreases in snow water equivalent (SWE), are a common approach to scale-up <span class="hlt">snowmelt</span> models....</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011TCry....5.1099G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011TCry....5.1099G"><span>Glacier contribution to <span class="hlt">streamflow</span> in two headwaters of the Huasco River, Dry Andes of Chile</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gascoin, S.; Kinnard, C.; Ponce, R.; Lhermitte, S.; MacDonell, S.; Rabatel, A.</p> <p>2011-12-01</p> <p>Quantitative assessment of glacier contribution to present-day <span class="hlt">streamflow</span> is a prerequisite to the anticipation of climate change impact on water resources in the Dry Andes. In this paper we focus on two glaciated headwater catchments of the Huasco Basin (Chile, 29° S). The combination of glacier monitoring data for five glaciers (Toro 1, Toro 2, Esperanza, Guanaco, Estrecho and Ortigas) with five automatic <span class="hlt">streamflow</span> records at sites with glacier coverage of 0.4 to 11 % allows the estimation of the mean annual glacier contribution to discharge between 2003/2004 and 2007/2008 hydrological years. In addition, direct manual measurements of glacier runoff were conducted in summer at the snouts of four glaciers, which provide the instantaneous contribution of glacier meltwater to stream runoff during summer. The results show that the mean annual glacier contribution to <span class="hlt">streamflow</span> ranges between 3.3 and 23 %, which is greater than the glaciated fraction of the catchments. We argue that glacier contribution is partly enhanced by the effect of snowdrift from the non-glacier area to the glacier surface. Glacier mass loss is evident over the study period, with a mean of -0.84 m w.e. yr-1 for the period 2003/2004-2007/2008, and also contributes to increase glacier runoff. An El Niño episode in 2002 resulted in high snow accumulation, modifying the hydrological regime and probably reducing the glacier contribution in favor of seasonal <span class="hlt">snowmelt</span> during the subsequent 2002/2003 hydrological year. At the hourly timescale, summertime glacier contributions are highly variable in space and time, revealing large differences in effective melting rates between glaciers and glacierets (from 1 mm w.e. h-1 to 6 mm w.e. h-1).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70030000','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70030000"><span>Detection, attribution, and sensitivity of trends toward earlier <span class="hlt">streamflow</span> in the Sierra Nevada</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Maurer, E.P.; Stewart, I.T.; Bonfils, Celine; Duffy, P.B.; Cayan, D.</p> <p>2007-01-01</p> <p>Observed changes in the timing of <span class="hlt">snowmelt</span> dominated <span class="hlt">streamflow</span> in the western United States are often linked to anthropogenic or other external causes. We assess whether observed <span class="hlt">streamflow</span> timing changes can be statistically attributed to external forcing, or whether they still lie within the bounds of natural (internal) variability for four large Sierra Nevada (CA) basins, at inflow points to major reservoirs. <span class="hlt">Streamflow</span> timing is measured by "center timing" (CT), the day when half the annual flow has passed a given point. We use a physically based hydrology model driven by meteorological input from a global climate model to quantify the natural variability in CT trends. Estimated 50-year trends in CT due to natural climate variability often exceed estimated actual CT trends from 1950 to 1999. Thus, although observed trends in CT to date may be statistically significant, they cannot yet be statistically attributed to external influences on climate. We estimate that projected CT changes at the four major reservoir inflows will, with 90% confidence, exceed those from natural variability within 1-4 decades or 4-8 decades, depending on rates of future greenhouse gas emissions. To identify areas most likely to exhibit CT changes in response to rising temperatures, we calculate changes in CT under temperature increases from 1 to 5??. We find that areas with average winter temperatures between -2??C and -4??C are most likely to respond with significant CT shifts. Correspondingly, elevations from 2000 to 2800 in are most sensitive to temperature increases, with CT changes exceeding 45 days (earlier) relative to 1961-1990. Copyright 2007 by the American Geophysical Union.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007JGRD..11211118M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007JGRD..11211118M"><span>Detection, attribution, and sensitivity of trends toward earlier <span class="hlt">streamflow</span> in the Sierra Nevada</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Maurer, E. P.; Stewart, I. T.; Bonfils, C.; Duffy, P. B.; Cayan, D.</p> <p>2007-06-01</p> <p>Observed changes in the timing of <span class="hlt">snowmelt</span> dominated <span class="hlt">streamflow</span> in the western United States are often linked to anthropogenic or other external causes. We assess whether observed <span class="hlt">streamflow</span> timing changes can be statistically attributed to external forcing, or whether they still lie within the bounds of natural (internal) variability for four large Sierra Nevada (CA) basins, at inflow points to major reservoirs. <span class="hlt">Streamflow</span> timing is measured by "center timing" (CT), the day when half the annual flow has passed a given point. We use a physically based hydrology model driven by meteorological input from a global climate model to quantify the natural variability in CT trends. Estimated 50-year trends in CT due to natural climate variability often exceed estimated actual CT trends from 1950 to 1999. Thus, although observed trends in CT to date may be statistically significant, they cannot yet be statistically attributed to external influences on climate. We estimate that projected CT changes at the four major reservoir inflows will, with 90% confidence, exceed those from natural variability within 1-4 decades or 4-8 decades, depending on rates of future greenhouse gas emissions. To identify areas most likely to exhibit CT changes in response to rising temperatures, we calculate changes in CT under temperature increases from 1 to 5°. We find that areas with average winter temperatures between -2°C and -4°C are most likely to respond with significant CT shifts. Correspondingly, elevations from 2000 to 2800 m are most sensitive to temperature increases, with CT changes exceeding 45 days (earlier) relative to 1961-1990.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/pages/biblio/1313012-deciduous-trees-large-overlooked-sink-snowmelt-water-boreal-forest','SCIGOV-DOEP'); return false;" href="https://www.osti.gov/pages/biblio/1313012-deciduous-trees-large-overlooked-sink-snowmelt-water-boreal-forest"><span>Deciduous trees are a large and overlooked sink for <span class="hlt">snowmelt</span> water in the boreal forest</span></a></p> <p><a target="_blank" href="http://www.osti.gov/pages">DOE PAGES</a></p> <p>Young-Robertson, Jessica M.; Bolton, W. Robert; Bhatt, Uma S.; ...</p> <p>2016-07-12</p> <p>The terrestrial water cycle contains large uncertainties that impact our understanding of water budgets and climate dynamics. Water storage is a key uncertainty in the boreal water budget, with tree water storage often ignored. The goal of this study is to quantify tree water content during the <span class="hlt">snowmelt</span> and growing season periods for Alaskan and western Canadian boreal forests. Deciduous trees reached saturation between <span class="hlt">snowmelt</span> and leaf-out, taking up 21–25% of the available <span class="hlt">snowmelt</span> water, while coniferous trees removed <1%. We found that deciduous trees removed 17.8–20.9 billion m3 of <span class="hlt">snowmelt</span> water, which is equivalent to 8.7–10.2% of the Yukonmore » River’s annual discharge. Deciduous trees transpired 2–12% (0.4–2.2 billion m3) of the absorbed <span class="hlt">snowmelt</span> water immediately after leaf-out, increasing favorable conditions for atmospheric convection, and an additional 10–30% (2.0–5.2 billion m3) between leaf-out and mid-summer. By 2100, boreal deciduous tree area is expected to increase by 1–15%, potentially resulting in an additional 0.3–3 billion m3 of <span class="hlt">snowmelt</span> water removed from the soil per year. Furthermore, this study is the first to show that deciduous tree water uptake of <span class="hlt">snowmelt</span> water represents a large but overlooked aspect of the water balance in boreal watersheds.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1313012','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1313012"><span>Deciduous trees are a large and overlooked sink for <span class="hlt">snowmelt</span> water in the boreal forest</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Young-Robertson, Jessica M.; Bolton, W. Robert; Bhatt, Uma S.; Cristobal, Jordi; Thoman, Richard</p> <p>2016-07-12</p> <p>The terrestrial water cycle contains large uncertainties that impact our understanding of water budgets and climate dynamics. Water storage is a key uncertainty in the boreal water budget, with tree water storage often ignored. The goal of this study is to quantify tree water content during the <span class="hlt">snowmelt</span> and growing season periods for Alaskan and western Canadian boreal forests. Deciduous trees reached saturation between <span class="hlt">snowmelt</span> and leaf-out, taking up 21–25% of the available <span class="hlt">snowmelt</span> water, while coniferous trees removed <1%. We found that deciduous trees removed 17.8–20.9 billion m<sup>3</sup> of <span class="hlt">snowmelt</span> water, which is equivalent to 8.7–10.2% of the Yukon River’s annual discharge. Deciduous trees transpired 2–12% (0.4–2.2 billion m<sup>3</sup>) of the absorbed <span class="hlt">snowmelt</span> water immediately after leaf-out, increasing favorable conditions for atmospheric convection, and an additional 10–30% (2.0–5.2 billion m<sup>3</sup>) between leaf-out and mid-summer. By 2100, boreal deciduous tree area is expected to increase by 1–15%, potentially resulting in an additional 0.3–3 billion m<sup>3</sup> of <span class="hlt">snowmelt</span> water removed from the soil per year. Furthermore, this study is the first to show that deciduous tree water uptake of <span class="hlt">snowmelt</span> water represents a large but overlooked aspect of the water balance in boreal watersheds.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4941571','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4941571"><span>Deciduous trees are a large and overlooked sink for <span class="hlt">snowmelt</span> water in the boreal forest</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Young-Robertson, Jessica M.; Bolton, W. Robert; Bhatt, Uma S.; Cristóbal, Jordi; Thoman, Richard</p> <p>2016-01-01</p> <p>The terrestrial water cycle contains large uncertainties that impact our understanding of water budgets and climate dynamics. Water storage is a key uncertainty in the boreal water budget, with tree water storage often ignored. The goal of this study is to quantify tree water content during the <span class="hlt">snowmelt</span> and growing season periods for Alaskan and western Canadian boreal forests. Deciduous trees reached saturation between <span class="hlt">snowmelt</span> and leaf-out, taking up 21–25% of the available <span class="hlt">snowmelt</span> water, while coniferous trees removed <1%. We found that deciduous trees removed 17.8–20.9 billion m3 of <span class="hlt">snowmelt</span> water, which is equivalent to 8.7–10.2% of the Yukon River’s annual discharge. Deciduous trees transpired 2–12% (0.4–2.2 billion m3) of the absorbed <span class="hlt">snowmelt</span> water immediately after leaf-out, increasing favorable conditions for atmospheric convection, and an additional 10–30% (2.0–5.2 billion m3) between leaf-out and mid-summer. By 2100, boreal deciduous tree area is expected to increase by 1–15%, potentially resulting in an additional 0.3–3 billion m3 of <span class="hlt">snowmelt</span> water removed from the soil per year. This study is the first to show that deciduous tree water uptake of <span class="hlt">snowmelt</span> water represents a large but overlooked aspect of the water balance in boreal watersheds. PMID:27404274</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li class="active"><span>13</span></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_13 --> <div id="page_14" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li class="active"><span>14</span></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="261"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009AGUFM.C33B0489J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009AGUFM.C33B0489J"><span>1996-2007 Interannual Spatio-Temporal Variability in <span class="hlt">Snowmelt</span> in Two Montane Watersheds</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jepsen, S. M.; Molotch, N. P.; Rittger, K. E.</p> <p>2009-12-01</p> <p><span class="hlt">Snowmelt</span> is a primary water source for ecosystems within, and urban/agricultural centers near, mountain regions. Stream chemistry from montane catchments is controlled by the flowpaths of water from <span class="hlt">snowmelt</span> and the timing and duration of snow coverage. A process level understanding of the variability in these processes requires an understanding of the effect of changing climate and anthropogenic loading on spatio-temporal <span class="hlt">snowmelt</span> patterns. With this as our objective, we are applying a snow reconstruction model to two well-studied montane watersheds, Tokopah Basin (TOK), California and Green Lakes Valley (GLV), Colorado, to examine interannual variability in the timing and location of <span class="hlt">snowmelt</span> in response to variable climate conditions during the period from 1996 to 2007. The reconstruction model back solves for <span class="hlt">snowmelt</span> by combining surface energy fluxes, inferred from meteorological data, with sequences of melt season snow images derived from satellite data (i.e., <span class="hlt">snowmelt</span> depletion curves). Preliminary model results for 2002 were tested against measured snow water equivalent (SWE) and hydrograph data for the two watersheds. The computed maximum SWE averaged over TOK and GLV were 94 cm (~+17% error) and 50.2 cm (~+1% error), respectively. We present an analysis of interannual variability in these errors, in addition to reconstructed <span class="hlt">snowmelt</span> maps over different land cover types under changing climate conditions between 1996-2007, focusing on the variability with interannual variation in climate.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016NatSR...629504Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016NatSR...629504Y"><span>Deciduous trees are a large and overlooked sink for <span class="hlt">snowmelt</span> water in the boreal forest</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Young-Robertson, Jessica M.; Bolton, W. Robert; Bhatt, Uma S.; Cristóbal, Jordi; Thoman, Richard</p> <p>2016-07-01</p> <p>The terrestrial water cycle contains large uncertainties that impact our understanding of water budgets and climate dynamics. Water storage is a key uncertainty in the boreal water budget, with tree water storage often ignored. The goal of this study is to quantify tree water content during the <span class="hlt">snowmelt</span> and growing season periods for Alaskan and western Canadian boreal forests. Deciduous trees reached saturation between <span class="hlt">snowmelt</span> and leaf-out, taking up 21–25% of the available <span class="hlt">snowmelt</span> water, while coniferous trees removed <1%. We found that deciduous trees removed 17.8–20.9 billion m3 of <span class="hlt">snowmelt</span> water, which is equivalent to 8.7–10.2% of the Yukon River’s annual discharge. Deciduous trees transpired 2–12% (0.4–2.2 billion m3) of the absorbed <span class="hlt">snowmelt</span> water immediately after leaf-out, increasing favorable conditions for atmospheric convection, and an additional 10–30% (2.0–5.2 billion m3) between leaf-out and mid-summer. By 2100, boreal deciduous tree area is expected to increase by 1–15%, potentially resulting in an additional 0.3–3 billion m3 of <span class="hlt">snowmelt</span> water removed from the soil per year. This study is the first to show that deciduous tree water uptake of <span class="hlt">snowmelt</span> water represents a large but overlooked aspect of the water balance in boreal watersheds.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70184337','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70184337"><span>Deciduous trees are a large and overlooked sink for <span class="hlt">snowmelt</span> water in the boreal forest</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Young, Jessica; Bolton, W. Robert; Bhatt, Uma; Cristobal, Jordi; Thoman, Richard</p> <p>2016-01-01</p> <p>The terrestrial water cycle contains large uncertainties that impact our understanding of water budgets and climate dynamics. Water storage is a key uncertainty in the boreal water budget, with tree water storage often ignored. The goal of this study is to quantify tree water content during the <span class="hlt">snowmelt</span> and growing season periods for Alaskan and western Canadian boreal forests. Deciduous trees reached saturation between <span class="hlt">snowmelt</span> and leaf-out, taking up 21–25% of the available <span class="hlt">snowmelt</span> water, while coniferous trees removed <1%. We found that deciduous trees removed 17.8–20.9 billion m3 of <span class="hlt">snowmelt</span> water, which is equivalent to 8.7–10.2% of the Yukon River’s annual discharge. Deciduous trees transpired 2–12% (0.4–2.2 billion m3) of the absorbed <span class="hlt">snowmelt</span> water immediately after leaf-out, increasing favorable conditions for atmospheric convection, and an additional 10–30% (2.0–5.2 billion m3) between leaf-out and mid-summer. By 2100, boreal deciduous tree area is expected to increase by 1–15%, potentially resulting in an additional 0.3–3 billion m3 of <span class="hlt">snowmelt</span> water removed from the soil per year. This study is the first to show that deciduous tree water uptake of <span class="hlt">snowmelt</span> water represents a large but overlooked aspect of the water balance in boreal watersheds.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27404274','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27404274"><span>Deciduous trees are a large and overlooked sink for <span class="hlt">snowmelt</span> water in the boreal forest.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Young-Robertson, Jessica M; Bolton, W Robert; Bhatt, Uma S; Cristóbal, Jordi; Thoman, Richard</p> <p>2016-07-12</p> <p>The terrestrial water cycle contains large uncertainties that impact our understanding of water budgets and climate dynamics. Water storage is a key uncertainty in the boreal water budget, with tree water storage often ignored. The goal of this study is to quantify tree water content during the <span class="hlt">snowmelt</span> and growing season periods for Alaskan and western Canadian boreal forests. Deciduous trees reached saturation between <span class="hlt">snowmelt</span> and leaf-out, taking up 21-25% of the available <span class="hlt">snowmelt</span> water, while coniferous trees removed <1%. We found that deciduous trees removed 17.8-20.9 billion m(3) of <span class="hlt">snowmelt</span> water, which is equivalent to 8.7-10.2% of the Yukon River's annual discharge. Deciduous trees transpired 2-12% (0.4-2.2 billion m(3)) of the absorbed <span class="hlt">snowmelt</span> water immediately after leaf-out, increasing favorable conditions for atmospheric convection, and an additional 10-30% (2.0-5.2 billion m(3)) between leaf-out and mid-summer. By 2100, boreal deciduous tree area is expected to increase by 1-15%, potentially resulting in an additional 0.3-3 billion m(3) of <span class="hlt">snowmelt</span> water removed from the soil per year. This study is the first to show that deciduous tree water uptake of <span class="hlt">snowmelt</span> water represents a large but overlooked aspect of the water balance in boreal watersheds.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017HESS...21.4053W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017HESS...21.4053W"><span>Simulating the influence of snow surface processes on soil moisture dynamics and <span class="hlt">streamflow</span> generation in an alpine catchment</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wever, Nander; Comola, Francesco; Bavay, Mathias; Lehning, Michael</p> <p>2017-08-01</p> <p>The assessment of flood risks in alpine, snow-covered catchments requires an understanding of the linkage between the snow cover, soil and discharge in the stream network. Here, we apply the comprehensive, distributed model Alpine3D to investigate the role of soil moisture in the predisposition of the Dischma catchment in Switzerland to high flows from rainfall and <span class="hlt">snowmelt</span>. The recently updated soil module of the physics-based multilayer snow cover model SNOWPACK, which solves the surface energy and mass balance in Alpine3D, is verified against soil moisture measurements at seven sites and various depths inside and in close proximity to the Dischma catchment. Measurements and simulations in such terrain are difficult and consequently, soil moisture was simulated with varying degrees of success. Differences between simulated and measured soil moisture mainly arise from an overestimation of soil freezing and an absence of a groundwater description in the Alpine3D model. Both were found to have an influence in the soil moisture measurements. Using the Alpine3D simulation as the surface scheme for a spatially explicit hydrologic response model using a travel time distribution approach for interflow and baseflow, <span class="hlt">streamflow</span> simulations were performed for the discharge from the catchment. The <span class="hlt">streamflow</span> simulations provided a closer agreement with observed <span class="hlt">streamflow</span> when driving the hydrologic response model with soil water fluxes at 30 cm depth in the Alpine3D model. Performance decreased when using the 2 cm soil water flux, thereby mostly ignoring soil processes. This illustrates that the role of soil moisture is important to take into account when understanding the relationship between both snowpack runoff and rainfall and catchment discharge in high alpine terrain. However, using the soil water flux at 60 cm depth to drive the hydrologic response model also decreased its performance, indicating that an optimal soil depth to include in surface simulations exists and</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JGRC..121.5916A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JGRC..121.5916A"><span>Timing and regional patterns of <span class="hlt">snowmelt</span> on Antarctic sea ice from passive microwave satellite observations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Arndt, Stefanie; Willmes, Sascha; Dierking, Wolfgang; Nicolaus, Marcel</p> <p>2016-08-01</p> <p>An improved understanding of the temporal variability and the spatial distribution of <span class="hlt">snowmelt</span> on Antarctic sea ice is crucial to better quantify atmosphere-ice-ocean interactions, in particular sea-ice mass and energy budgets. It is therefore important to understand the mechanisms that drive <span class="hlt">snowmelt</span>, both at different times of the year and in different regions around Antarctica. In this study, we combine diurnal brightness temperature differences (dTB(37 GHz)) and ratios (TB(19 GHz)/TB(37 GHz)) to detect and classify <span class="hlt">snowmelt</span> processes. We distinguish temporary <span class="hlt">snowmelt</span> from continuous <span class="hlt">snowmelt</span> to characterize dominant melt patterns for different Antarctic sea-ice regions from 1988/1989 to 2014/2015. Our results indicate four characteristic melt types. On average, 38.9 ± 6.0% of all detected melt events are diurnal freeze-thaw cycles in the surface snow layer, characteristic of temporary melt (Type A). Less than 2% reveal immediate continuous <span class="hlt">snowmelt</span> throughout the snowpack, i.e., strong melt over a period of several days (Type B). In 11.7 ± 4.0%, Type A and B take place consecutively (Type C), and for 47.8 ± 6.8% no surface melt is observed at all (Type D). Continuous <span class="hlt">snowmelt</span> is primarily observed in the outflow of the Weddell Gyre and in the northern Ross Sea, usually 17 days after the onset of temporary melt. Comparisons with Snow Buoy data suggest that also the onset of continuous <span class="hlt">snowmelt</span> does not translate into changes in snow depth for a longer period but might rather affect the internal stratigraphy and density structure of the snowpack. Considering the entire data set, the timing of <span class="hlt">snowmelt</span> processes does not show significant temporal trends.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016ERL....11d4015F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016ERL....11d4015F"><span>Energy budget increases reduce mean <span class="hlt">streamflow</span> more than snow-rain transitions: using integrated modeling to isolate climate change impacts on Rocky Mountain hydrology</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Foster, Lauren M.; Bearup, Lindsay A.; Molotch, Noah P.; Brooks, Paul D.; Maxwell, Reed M.</p> <p>2016-04-01</p> <p>In snow-dominated mountain regions, a warming climate is expected to alter two drivers of hydrology: (1) decrease the fraction of precipitation falling as snow; and (2) increase surface energy available to drive evapotranspiration. This study uses a novel integrated modeling approach to explicitly separate energy budget increases via warming from precipitation phase transitions from snow to rain in two mountain headwaters transects of the central Rocky Mountains. Both phase transitions and energy increases had significant, though unique, impacts on semi-arid mountain hydrology in our simulations. A complete shift in precipitation from snow to rain reduced <span class="hlt">streamflow</span> between 11% and 18%, while 4 °C of uniform warming reduced <span class="hlt">streamflow</span> between 19% and 23%, suggesting that changes in energy-driven evaporative loss, between 27% and 29% for these uniform warming scenarios, may be the dominant driver of annual mean <span class="hlt">streamflow</span> in a warming climate. Phase changes induced a flashier system, making water availability more susceptible to precipitation variability and eliminating the runoff signature characteristic of <span class="hlt">snowmelt</span>-dominated systems. The impact of a phase change on mean <span class="hlt">streamflow</span> was reduced as aridity increased from west to east of the continental divide.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.H31H1533P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.H31H1533P"><span>Explaining <span class="hlt">streamflow</span> variability of the Gila and Rio Grande rivers : Pacific teleconnections and catchment-scale interaction of the hydrological cycle with vegetation and soil moisture</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pascolini-Campbell, M.; Seager, R.</p> <p>2015-12-01</p> <p>The <span class="hlt">streamflows</span> of the Gila River, N.M. and the upper Rio Grande, with headwaters in Colorado are influenced by a range of drivers including the El Nino-Southern Oscillation (ENSO), the Pacific Decadal Oscillation (PDO), the Atlantic Multidecadal Oscillation (AMO) and, for the Gila, the North American Monsoon. At the catchment scale, runoff to the river is modulated by the interaction of <span class="hlt">snowmelt</span>, rainfall, evapotranspiration, soil moisture and vegetation. A simple eco-hydological model is used to explain the seasonal cycles of flow of the Gila (strong spring peak, weak summer peak) and upper Rio Grande (single spring peak) in terms of precipitation, snowpack, and evapotranspiration. We then examine the drivers of <span class="hlt">streamflow</span> variability using USGS gages located upstream of human extraction, precipitation and temperature data from PRISM, and SST data from ERSST. High spring <span class="hlt">streamflow</span> tends to occur in response to prior winter El Nino but not all high and low <span class="hlt">streamflow</span> events can be explained by the Pacific teleconnection. Decadal variations, including low flows in the Gila and upper Rio Grande since the mid 1990s, are explained in terms of the Pacific and Atlantic Ocean decadal variability.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..1917777B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..1917777B"><span>Characterizing the spatial correlation of <span class="hlt">streamflows</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Betterle, Andrea; Schirmer, Mario; Botter, Gianluca</p> <p>2017-04-01</p> <p>The spatial variability of <span class="hlt">streamflow</span> dynamics is the byproduct of complex interactions between heterogeneous climatic, morphological, geological and ecological conditions across the landscape. The spatial correlation or <span class="hlt">streamflows</span> represents a synthetic statistical indicator of similarity between flow dynamics at two arbitrary river sites. <span class="hlt">Streamflow</span> correlation can therefore be used to track changes in flow dynamics along river networks, with implications for studies where spatial patterns of flow regimes are critical. In this work we develop an analytical model to quantify the seasonal linear correlation between daily <span class="hlt">streamflow</span> timeseries at the outlet of two arbitrary unregulated catchment. The framework is based on a parsimonious and physically based stochastic description of the main geomorphoclimatic drivers of flow dynamics, ultimately leading to analytical expressions for the flow correlation. <span class="hlt">Streamflow</span> correlation between two rivers sites results as a function of the main physical drivers characterizing flow dynamics at the relevant sites, namely the frequency and intensity of runoff-generating rainfall, and the catchment recession rates. The performances of the model are assessed on a set of catchment in the Eastern United States providing satisfactory performances. Different parameter estimation techniques are also developed, including a method which enables the estimate of the <span class="hlt">streamflow</span> correlation in absence of discharge data. The role played by the spatial heterogeneities of the hydrological processes considered in the model on the resulting <span class="hlt">streamflow</span> correlation are analytically assessed and evaluated in the study sites. The analysis shows how seasonal spatial correlation of flow dynamics is mainly controlled by the frequency and intensity of runoff-generating rainfall events, whereas heterogeneous recession rates have a limited influence in the study area. Additionally, the framework accounts for the topological arrangement or river networks</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.usgs.gov/wri/1996/4115/report.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/wri/1996/4115/report.pdf"><span>Geohydrology of stratified drift and <span class="hlt">streamflow</span> in the Deerfield River basin, northwestern Massachusetts</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Friesz, P.J.</p> <p>1996-01-01</p> <p>This report presents the results of a study of the geohydrology of stratified drift and <span class="hlt">streamflow</span> in the Deerfield River Basin, northwestern Massachusetts. Detailed hydrologic information is needed to plan for the optimal use of ground-water and surface-water resources and for development of new drinking-water supplies in the basin. Sources and percentage of water available for recharge on an annual basis from October 1993 to September 1994, to the fine-grained stratified-drift in a narrow valley bordered by upland till and bedrock were: (1) direct infiltration of precipitation on the valley (30 percent); (2) tributary loss from an upland brook as it crosses the valley (7 percent); and (3) ground- and surface-water runoff from the uplands (63 percent). Seventy percent of recharge was available from upland sources. Seasonal variation in recharge caused changes in ground-water levels and flow directions. In early spring, the direction of flow is toward the valley axis, but in late summer, the direction of flow is nearly parallel to the valley axis. Field observations and results of a ground-water flow simulation indicated that water available for recharge was greater than actual recharge during the spring <span class="hlt">snowmelt</span> and during intense precipitation events. In 1994, estimates of water available for recharge were greater than actual recharge by 10 percent in March and by 60 percent in April; actual recharge to the valley on an annual basis from October 1993 to September 1994 was 20 percent less than original estimates. A map showing thickness of stratified drift in the Connecticut Valley Lowlands indicates a deep north-south trending buried valley. Maximum thickness of the stratified drift is 385 feet. Interpretation of a seismic-reflection survey indicates fine-grained stratified drift may be underlain by coarse-grained deposits ranging in thickness from 0 to 150 feet. Hydraulic properties of the stratified drift were calculated from ground-water-level fluctuations</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70015428','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70015428"><span>Problems of <span class="hlt">snowmelt</span> runoff modelling for a variety of physiographic and climatic conditions</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Leavesley, G.H.</p> <p>1989-01-01</p> <p>Problems include: a) definition of the spatial and temporal distribution of model input; b) measurement or estimation of snow accumulation, <span class="hlt">snowmelt</span>, and runoff process parameters for a range of applications and scales; and c) development of accurate short term and long term <span class="hlt">snowmelt</span> runoff forecasts. Procedures being investigated to solve these problems include: a) integrating conventional and remote-sensing data to improve estimates of input data; b) developing <span class="hlt">snowmelt</span> process algorithms which have parameters that are closely related to measurable basin and climatic characteristics; and c) updating model paramters and components using measured data or knowledge of past uncertainty. -from Author</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..1912230C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..1912230C"><span>Application of global datasets for hydrological modelling of a remote, <span class="hlt">snowmelt</span> driven catchment in the Canadian Sub-Arctic</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Casson, David; Werner, Micha; Weerts, Albrecht; Schellekens, Jaap; Solomatine, Dimitri</p> <p>2017-04-01</p> <p> that validation of actual frozen precipitation and snowpack conditions is very difficult. The distributed hydrological model shows good <span class="hlt">streamflow</span> simulation performance based on statistical model evaluation techniques. Results are also promising for inter-annual variability, spring <span class="hlt">snowmelt</span> onset and time to peak flows. It is expected that data assimilation of stream flow using an Ensemble Kalman Filter will further improve model performance. This study shows that global re-analysis datasets hold great potential for understanding the hydrology and snowpack dynamics of the expansive and data sparse sub-Arctic. However, global SWE products will require further validation and algorithm improvements, particularly over boreal forest and lake-rich regions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015WRR....51.8551W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015WRR....51.8551W"><span>Modeling the influence of hypsometry, vegetation, and storm energy on <span class="hlt">snowmelt</span> contributions to basins during rain-on-snow floods</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wayand, Nicholas E.; Lundquist, Jessica D.; Clark, Martyn P.</p> <p>2015-10-01</p> <p>Point observations and previous basin modeling efforts have suggested that <span class="hlt">snowmelt</span> may be a significant input of water for runoff during extreme rain-on-snow floods within western U.S. basins. Quantifying <span class="hlt">snowmelt</span> input over entire basins is difficult given sparse observations of <span class="hlt">snowmelt</span>. In order to provide a range of <span class="hlt">snowmelt</span> contributions for water managers, a physically based snow model coupled with an idealized basin representation was evaluated in point simulations and used to quantify the maximum basin-wide input from <span class="hlt">snowmelt</span> volume during flood events. Maximum <span class="hlt">snowmelt</span> basin contributions and uncertainty ranges were estimated as 29% (11-47%), 29% (8-37%), and 7% (2-24%) of total rain plus <span class="hlt">snowmelt</span> input, within the Snoqualmie, East North Fork Feather, and Upper San Joaquin basins, respectively, during historic flooding events between 1980 and 2008. The idealized basin representation revealed that both hypsometry and forest cover of a basin had similar magnitude of impacts on the basin-wide <span class="hlt">snowmelt</span> totals. However, the characteristics of a given storm (antecedent SWE and available energy for melt) controlled how much hypsometry and forest cover impacted basin-wide <span class="hlt">snowmelt</span>. These results indicate that for watershed managers, flood forecasting efforts should prioritize rainfall prediction first, but cannot neglect <span class="hlt">snowmelt</span> contributions in some cases. Efforts to reduce the uncertainty in the above <span class="hlt">snowmelt</span> simulations should focus on improving the meteorological forcing data (especially air temperature and wind speed) in complex terrain.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.usgs.gov/sir/2013/5005/sir2013-5005.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/sir/2013/5005/sir2013-5005.pdf"><span>Water quality, <span class="hlt">streamflow</span> conditions, and annual flow-duration curves for streams of the San Juan–Chama Project, southern Colorado and northern New Mexico, 1935-2010</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Falk, Sarah E.; Anderholm, Scott K.; Hafich, Katya A.</p> <p>2013-01-01</p> <p>, 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 <span class="hlt">streamflow</span> conditions throughout the year. <span class="hlt">Streamflow</span> in spring and summer is generally a mixture of base flow (the component of <span class="hlt">streamflow</span> derived from groundwater discharged to the stream channel) diluted with runoff from <span class="hlt">snowmelt</span> and precipitation events, whereas <span class="hlt">streamflow</span> 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 <span class="hlt">snowmelt</span> 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 <span class="hlt">streamflow</span> indicators occurred at dates later in the year than the years with less <span class="hlt">snowmelt</span> runoff. Additionally, the seasonal distribution of <span class="hlt">streamflow</span> was more strongly controlled by the change in the amount of annual discharge than by changes in <span class="hlt">streamflow</span> over time. The variation of <span class="hlt">streamflow</span> conditions over time at one <span class="hlt">streamflow</span>-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</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.H41A1284N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.H41A1284N"><span>Impacts of Climate Change on Groundwater Recharge and <span class="hlt">Streamflow</span> in Headwater Catchments in the Yakima River Basin</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Nguyen, T. T.; Adam, J. C.</p> <p>2015-12-01</p> <p>Headwater catchments are important sources of surface water supply, groundwater recharge and, thus, groundwater supply for agricultural activities in the Yakima River Basin (YRB, one of the most important agricultural basins in the western U.S). These catchments are, however, vulnerable to projected climate change in future decades, particularly if their runoff is dominated by <span class="hlt">snowmelt</span>. The goal of this study is to assess the potential impacts of climate change on the temporal and spatial distributions of groundwater recharge and <span class="hlt">streamflow</span> in three headwater catchments in the YRB. A Regional Hydro-Ecologic Simulation System ("RHESSys") is calibrated and evaluated with a global optimization tool ("Covariance Matrix Adaptation Evolution Strategy - CMA-ES") using 27 years of observation data from 1979 to 2005. Statistically downscaled climate projections for the 2050s from four global climate models driven by two different representative concentration pathways, RCP4.5 and RCP8.5 are used to predict future hydrologic changes. Our preliminary results show an increase in annual recharge between 2% and 13%, as well as in <span class="hlt">streamflow</span> between 1% and 17%. Seasonal changes of recharge and <span class="hlt">streamflow</span> are more pronounced with an increase up to 210% in winters and a decrease as high as 60% in summers in the 2050s. Both recharge and <span class="hlt">streamflow</span> projections indicate timing shifts in all three catchments. The outcome from this study will be an integral part of a future study which investigates the impacts of climate change on surface water vulnerability due to supplemental pumping, potential recharge changes and related surface-groundwater interactions in the YRB using an integrated modeling approach that consists of three models: RHESSys, a groundwater model (MODFLOW) and a river and reservoir management model (RiverWare).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=67132&keyword=snowpack&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50&CFID=90597565&CFTOKEN=53571408','EPA-EIMS'); return false;" href="http://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=67132&keyword=snowpack&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50&CFID=90597565&CFTOKEN=53571408"><span>THE INFLUENCE OF THE SPATIAL DISTRIBUTION OF SNOW ON BASIN-AVERAGED <span class="hlt">SNOWMELT</span>. (R824784)</span></a></p> <p><a target="_blank" href="http://oaspub.epa.gov/eims/query.page">EPA Science Inventory</a></p> <p></p> <p></p> <p>Spatial variability in snow accumulation and melt owing to topographic effects on solar radiation, snow drifting, air temperature and precipitation is important in determining the timing of <span class="hlt">snowmelt</span> releases. Precipitation and temperature effects related to topography affect snow...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005GeoRL..3221412G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005GeoRL..3221412G"><span>The impact of snow depth and <span class="hlt">snowmelt</span> on the vegetation variability over central Siberia</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Grippa, M.; Kergoat, L.; Le Toan, T.; Mognard, N. M.; Delbart, N.; L'Hermitte, J.; Vicente-Serrano, S. M.</p> <p>2005-11-01</p> <p>We report the results of a joint analysis of NDVI data derived from NOAA-AVHRR and snow parameters (snow depth and <span class="hlt">snowmelt</span> timing) derived from satellite passive microwave measurements over Central Siberia. We investigate the influence of interannual variability in <span class="hlt">snowmelt</span> and snow depth on vegetation activity from 1989 to 2000. In addition to the effects of temperature and precipitation, we observe significant correlations between the snow parameters and the NDVI. Later <span class="hlt">snowmelt</span> dates and thicker winter snowpacks are related to higher NDVI values over a large latitudinal band at about 65°N. This may be explained by either increased water availability for plants after <span class="hlt">snowmelt</span> or thermal insulation of soil by snow. These results reflect the importance of snow-related winter processes on the vegetation development and on the carbon cycle in boreal regions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/6749883','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/6749883"><span>Transport of plutonium in <span class="hlt">snowmelt</span> run-off</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Purtymun, W.D.; Peters, R.; Maes, M.N.</p> <p>1990-07-01</p> <p>Plutonium in treated low-level radioactive effluents released into intermittent streams is bound by ion exchange or adsorption to bed sediments in the stream channel. These sediments are subject to transport with summer and spring <span class="hlt">snowmelt</span> run-off. A study was made of the transport of plutonium during seven spring run-off events in Los Alamos and Pueblo canyons from the Laboratory boundary to Otowi on the Rio Grande. The melting of the snowpack during these years resulted in run-off that was large enough to reach the eastern edge of the Laboratory. Of these seven run-off events recorded at the Laboratory boundary, only five had sufficient flow to reach the Rio Grande. The volume of the five events that reached the river ranged from 5 {times} 10{sup 3} m{sup 3} to 104 {times} 10{sup 3} m{sup 3}. The five run-off events carried 119 {times} 10{sup 3} kg of suspended sediments and 1073 {times} 10{sup 3} kg of bed sediments, and transported 598 {mu}Ci of plutonium to the river. Of the 598 {mu}Ci of plutonium, 3% was transported in solution, 57% with suspended sediments, and 40% with bed sediments. 13 refs., 3 figs., 6 tabs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://cfpub.epa.gov/si/si_public_record_report.cfm?direntryid=336266&keyword=climate%20change&subject=climate%20change%20research&showcriteria=2&datebeginpublishedpresented=08/03/2012&dateendpublishedpresented=08/03/2017&sortby=pubdateyear&','PESTICIDES'); return false;" href="https://cfpub.epa.gov/si/si_public_record_report.cfm?direntryid=336266&keyword=climate%20change&subject=climate%20change%20research&showcriteria=2&datebeginpublishedpresented=08/03/2012&dateendpublishedpresented=08/03/2017&sortby=pubdateyear&"><span>Climate impacts on connectivity of <span class="hlt">snowmelt</span> to flow in the ...</span></a></p> <p><a target="_blank" href="http://www.epa.gov/pesticides/search.htm">EPA Pesticide Factsheets</a></p> <p></p> <p></p> <p>Much of the water that people in Western Oregon rely on comes from snowpack in the Cascade Range, and this snowpack is expected to decrease in coming years with climate change. In fact, the past 6 years have shown dramatic variation in snowpack, from a high of 174% of normal in 2010-11 to a low of 11% for 2014-15, one of the lowest on record. During this timeframe, we have monitored the stable isotopes of water within the Willamette River twice monthly, and mapped the spatial variation of water isotopes across the basin. Within the Willamette Basin, stable isotopes of water in precipitation vary strongly with elevation and provide a marker for determining the mean elevation from which water in the Willamette River is derived. In winter, when snow accumulates in the mountains, low elevation precipitation (primarily rain) contributes the largest proportion of water to the Willamette River. During summer, when rainfall is scarce and demand for water is the greatest, water in the Willamette River is mainly derived from high elevation <span class="hlt">snowmelt</span>. Our data indicate that the proportion of water from high elevation decreased with decreasing snowpack. We combine this information with river flow data to estimate the volume reduction related to snowpack reduction during the dry summer. Observed reductions in the contribution of high elevation water to the Willamette River after just 2 years of diminished snowpack indicate that the hydrologic system responds relatively</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/17710918','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/17710918"><span>Metal distributions in soil receiving urban pavement runoff and <span class="hlt">snowmelt</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Sansalone, John J; Glenn, Donald W</p> <p>2007-07-01</p> <p>Wet and dry deposition of anthropogenic metals and particulates generated from urban and traffic activities can result in contamination of urban-land-use soils. These particulate residuals encompass a wide size gradation, from 1 to greater than 10 000 microm. This study hypothesized that such contamination of surficial soils can be analyzed and explained as a function of the soil/residual granulometry. This study analyzed the gradation-based physical characteristics for 10 urban transportation land-use sites with soil/residual complexes (SRCs) located throughout metropolitan Cincinnati, Ohio, and an urban residential reference site. Particle density (rho(s)) of SRCs ranged from 2.8 to 2.1 g/cm3, with the lower particle density associated with particles less than 100 microm. For each site, specific surface area generally increased with decreasing particle size, while the predominance of total surface area was associated with the coarser size fractions, except for the clayey glacial till reference site not influenced by traffic. Cumulative analysis for lead, copper, cadmium, and zinc associated with SRCs indicated that more than 50% of the metal mass was associated with particles greater than 250 microm, with more than 80% associated with particles greater than 106 microm. Study results are similar to rainfall-runoff and <span class="hlt">snowmelt</span> distributions. Results provide guidance when considering potential fate and control of metals transported by urban drainage and are distributed across the SRC size gradation.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li class="active"><span>14</span></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_14 --> <div id="page_15" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li class="active"><span>15</span></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="281"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.usgs.gov/wri/1987/4117/report.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/wri/1987/4117/report.pdf"><span>Evaluation of the flood hydrology in the Colorado Front Range using precipitation, <span class="hlt">streamflow</span>, and paleoflood data for the Big Thompson River basin</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Jarrett, R.D.; Costa, J.E.</p> <p>1988-01-01</p> <p>A multidisciplinary study of precipitation and <span class="hlt">streamflow</span> data and paleohydrologic studies of channel features was made to analyze the flood hydrology of foothill and mountain streams in the Front Range of Colorado, with emphasis on the Big Thompson River basin, because conventional hydrologic analyses do not adequately characterize the flood hydrology. In the foothills of Colorado, annual floodflows are derived from <span class="hlt">snowmelt</span> at high elevations in the mountain regions, from rainfall at low elevation in the plains or plateau regions, or from a combination of rain falling on snow or mixed population hydrology. Above approximately 7,500 ft, <span class="hlt">snowmelt</span> dominates; rain does not contribute to the flood potential. Regional flood-frequency relations were developed and compared with conventional flood-estimating technique results, including an evaluation of the magnitude and frequency of the probable maximum flood. Evaluation of <span class="hlt">streamflow</span> data and paleoflood investigations provide an alternative for evaluating flood hydrology and the safety of dams. The study indicates the need for additional data collection and research to understand the complexities of the flood hydrology in mountainous regions, especially its effects on flood-plain management and the design of structures in the flood plain. (USGS)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70035103','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70035103"><span>Trends in <span class="hlt">streamflow</span> in the Yukon River Basin from 1944 to 2005 and the influence of the Pacific Decadal Oscillation</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Brabets, T.P.; Walvoord, M.A.</p> <p>2009-01-01</p> <p><span class="hlt">Streamflow</span> characteristics in the Yukon River Basin of Alaska and Canada have changed from 1944 to 2005, and some of the change can be attributed to the two most recent modes of the Pacific Decadal Oscillation (PDO). Seasonal, monthly, and annual stream discharge data from 21 stations in the Yukon River Basin were analyzed for trends over the entire period of record, generally spanning 4-6 decades, and examined for differences between the two most recent modes of the PDO: cold-PDO (1944-1975) and warm-PDO (1976-2005) subsets. Between 1944 and 2005, average winter and April flow increased at 15 sites. Observed winter flow increases during the cold-PDO phase were generally limited to sites in the Upper Yukon River Basin. Positive trends in winter flow during the warm-PDO phase broadened to include stations in the Middle and Lower Yukon River drainage basins. Increases in winter <span class="hlt">streamflow</span> most likely result from groundwater input enhanced by permafrost thawing that promotes infiltration and deeper subsurface flow paths. Increased April flow may be attributed to a combination of greater baseflow (from groundwater increases), earlier spring <span class="hlt">snowmelt</span> and runoff, and increased winter precipitation, depending on location. Calculated deviations from long-term mean monthly discharges indicate below-average flow in the winter months during the cold PDO and above-average flow in the winter months during the warm PDO. Although not as strong a signal, results also support the reverse response during the summer months: above-average flow during the cold PDO and below-average flow during the warm PDO. Changes in the summer flows are likely an indirect consequence of the PDO, resulting from earlier spring <span class="hlt">snowmelt</span> runoff and also perhaps increased summer infiltration and storage in a deeper active layer. Annual discharge has remained relatively unchanged in the Yukon River Basin, but a few glacier-fed rivers demonstrate positive trends, which can be attributed to enhanced glacier</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=277755&keyword=geology&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50&CFID=78675326&CFTOKEN=61321265','EPA-EIMS'); return false;" href="http://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=277755&keyword=geology&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50&CFID=78675326&CFTOKEN=61321265"><span>How does spatial variability of climate affect catchment <span class="hlt">streamflow</span> predictions?</span></a></p> <p><a target="_blank" href="http://oaspub.epa.gov/eims/query.page">EPA Science Inventory</a></p> <p></p> <p></p> <p>Spatial variability of climate can negatively affect catchment <span class="hlt">streamflow</span> predictions if it is not explicitly accounted for in hydrologic models. In this paper, we examine the changes in <span class="hlt">streamflow</span> predictability when a hydrologic model is run with spatially variable (distribute...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=277755&keyword=Geology&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50','EPA-EIMS'); return false;" href="http://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=277755&keyword=Geology&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50"><span>How does spatial variability of climate affect catchment <span class="hlt">streamflow</span> predictions?</span></a></p> <p><a target="_blank" href="http://oaspub.epa.gov/eims/query.page">EPA Science Inventory</a></p> <p></p> <p></p> <p>Spatial variability of climate can negatively affect catchment <span class="hlt">streamflow</span> predictions if it is not explicitly accounted for in hydrologic models. In this paper, we examine the changes in <span class="hlt">streamflow</span> predictability when a hydrologic model is run with spatially variable (distribute...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..18.1872B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..18.1872B"><span><span class="hlt">Streamflow</span> sensitivity to water storage changes across Europe</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Berghuijs, Wouter; Hartmann, Andreas; Woods, Ross</p> <p>2016-04-01</p> <p>Terrestrial water storage is the primary source of river flow. We introduce storage sensitivity of <span class="hlt">streamflow</span>, which for a given flow rate indicates the relative change in <span class="hlt">streamflow</span> per change in catchment water storage. Storage sensitivity of <span class="hlt">streamflow</span> can be directly derived from <span class="hlt">streamflow</span> observations. Analysis of 725 catchments in Europe reveals that storage sensitivity of <span class="hlt">streamflow</span> is high in e.g. parts of Spain, England, Germany and Denmark, whereas flow regimes in parts of the Alps are more resilient (that is, less sensitive) to storage changes. A comparison of storage sensitivity of <span class="hlt">streamflow</span> with observations suggests that storage sensitivity of <span class="hlt">streamflow</span> is a significant control on the regional differences in variability of low, median, and high flow conditions. <span class="hlt">Streamflow</span> sensitivity provides new guidance for a changing hydrosphere where groundwater abstraction and climatic changes are altering water storage and flow regimes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014WRR....50.1448B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014WRR....50.1448B"><span><span class="hlt">Snowmelt</span> timing alters shallow but not deep soil moisture in the Sierra Nevada</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Blankinship, Joseph C.; Meadows, Matthew W.; Lucas, Ryan G.; Hart, Stephen C.</p> <p>2014-02-01</p> <p>Roughly one-third of the Earth's land surface is seasonally covered by snow. In many of these ecosystems, the spring snowpack is melting earlier due to climatic warming and atmospheric dust deposition, which could greatly modify soil water resources during the growing season. Though <span class="hlt">snowmelt</span> timing is known to influence soil water availability during summer, there is little known about the depth of the effects and how long the effects persist. We therefore manipulated the timing of seasonal <span class="hlt">snowmelt</span> in a high-elevation mixed-conifer forest in a Mediterranean climate during consecutive wet and dry years. The snow-all-gone (SAG) date was advanced by 6 days in the wet year and 3 days in the dry year using black sand to reduce the snow surface albedo. To maximize variation in <span class="hlt">snowmelt</span> timing, we also postponed the SAG date by 8 days in the wet year and 16 days in the dry year using white fabric to shade the snowpack from solar radiation. We found that deeper soil water (30-60 cm) did not show a statistically significant response to <span class="hlt">snowmelt</span> timing. Shallow soil water (0-30 cm), however, responded strongly to <span class="hlt">snowmelt</span> timing. The drying effect of accelerated <span class="hlt">snowmelt</span> lasted 2 months in the 0-15 cm depth and at least 4 months in the 15-30 cm depth. Therefore, the legacy of <span class="hlt">snowmelt</span> timing on soil moisture can persist through dry periods, and continued earlier <span class="hlt">snowmelt</span> due to climatic warming and windblown dust could reduce near-surface water storage and availability to plants and soil biota.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70182150','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70182150"><span>Soil-water dynamics and unsaturated storage during <span class="hlt">snowmelt</span> following wildfire</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Ebel, Brian A.; Hinckley, E.S.; Martin, Deborah</p> <p>2012-01-01</p> <p>Many forested watersheds with a substantial fraction of precipitation delivered as snow have the potential for landscape disturbance by wildfire. Little is known about the immediate effects of wildfire on <span class="hlt">snowmelt</span> and near-surface hydrologic responses, including soil-water storage. Montane systems at the rain-snow transition have soil-water dynamics that are further complicated during the <span class="hlt">snowmelt</span> period by strong aspect controls on <span class="hlt">snowmelt</span> and soil thawing. Here we present data from field measurements of snow hydrology and subsurface hydrologic and temperature responses during the first winter and spring after the September 2010 Fourmile Canyon Fire in Colorado, USA. Our observations of soil-water content and soil temperature show sharp contrasts in hydrologic and thermal conditions between north- and south-facing slopes. South-facing burned soils were ∼1–2 °C warmer on average than north-facing burned soils and ∼1.5 °C warmer than south-facing unburned soils, which affected soil thawing during the <span class="hlt">snowmelt</span> period. Soil-water dynamics also differed by aspect: in response to soil thawing, soil-water content increased approximately one month earlier on south-facing burned slopes than on north-facing burned slopes. While aspect and wildfire affect soil-water dynamics during <span class="hlt">snowmelt</span>, soil-water storage at the end of the <span class="hlt">snowmelt</span> period reached the value at field capacity for each plot, suggesting that post-<span class="hlt">snowmelt</span> unsaturated storage was not substantially influenced by aspect in wildfire-affected areas. Our data and analysis indicate that the amount of <span class="hlt">snowmelt</span>-driven groundwater recharge may be larger in wildfire-impacted areas, especially on south-facing slopes, because of earlier soil thaw and longer durations of soil-water contents above field capacity in those areas.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.usgs.gov/fs/2008/3099/','USGSPUBS'); return false;" href="https://pubs.usgs.gov/fs/2008/3099/"><span>Hydrologic <span class="hlt">Streamflow</span> Conditions for Georgia, 2007</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Knaak, Andrew E.; Joiner, John K.</p> <p>2008-01-01</p> <p>The U.S. Geologic Survey (USGS) Georgia Water Science Center (GaWSC) maintains a long-term hydrologic monitoring network of more than 260 real-time <span class="hlt">streamflow</span> stations and more than 100 noncontinuous <span class="hlt">streamflow</span> stations throughout Georgia. This network is operated by the USGS GaWSC in cooperation with more than 50 different partners at Federal, State, and local government levels. One of the many benefits of data collected from this monitoring network is that it allows for the analysis of the overall hydrologic condition of streams and lakes of Georgia.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/837929','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/837929"><span>Response of <span class="hlt">streamflow</span> to multiple earthquakes</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Manga, Michael; Brodsky, Emily E.; Boone, Michael</p> <p>2002-06-01</p> <p>We analyze the <span class="hlt">streamflow</span> response of Sespe Creek, CA, to several large earthquakes. We find that flow increased after three earthquakes, and that the observed changes in flow have the same character. Both those earthquakes that induced static extension and those that induced static contraction cause flow to increase; <span class="hlt">streamflow</span> thus appears to respond to dynamic strain. We find that all postseismic responses can be explained by a model in which pore pressure increases coseismically without any changes in hydraulic diffusivity. There is a particle velocity threshold in the range of 5-20 cm/s to induce the pore pressure increase. [References: 16</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016PhyA..442...91C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016PhyA..442...91C"><span>Maximum entropy spectral analysis for <span class="hlt">streamflow</span> forecasting</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cui, Huijuan; Singh, Vijay P.</p> <p>2016-01-01</p> <p>Configurational entropy spectral analysis (CESAS) is developed with spectral power as a random variable for <span class="hlt">streamflow</span> forecasting. It is found that the CESAS derived by maximizing the configurational entropy yields the same solution as by the Burg entropy spectral analysis (BESA). Comparison of forecasted <span class="hlt">streamflows</span> by CESAS and BESA shows less than 0.001% difference between the two analyses and thus the two entropy spectral analyses are concluded to be identical. Thus, the Burg entropy spectral analysis and two configurational entropy spectral analyses form the maximum entropy spectral analysis.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/15649','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/15649"><span>Proposed hydrologic analyses of <span class="hlt">streamflow</span> for Brazil</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Riggs, Henry Chiles</p> <p>1974-01-01</p> <p><span class="hlt">Streamflow</span> records are evaluated for the Rio Jacui basin in the state of Rio Grande Sul, Brazil, in reference to data reliability, length of record, and density of areal coverage. Availability of water is a factor in the development of a country, and surface water is of especial importance in Brazil. This report is intended as a reference for further investigation of the flow characteristic of the basin to provide (1) information for utilization of <span class="hlt">streamflow</span> and (2) information to improve the data collection and analytic procedures. In addition the evaluation study can serve as a pilot for other developing river basins in Brazil. (Woodard-USGS)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFM.B33D0645P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFM.B33D0645P"><span>Mercury Transport During <span class="hlt">Snowmelt</span> in the Upper Provo River, Utah, USA</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Packer, B. N.; Carling, G. T.; Aanderud, Z.; Nelson, S.</p> <p>2016-12-01</p> <p>Transport of mercury (Hg) during <span class="hlt">snowmelt</span> is widely recognized as a significant source of Hg to high elevation lakes and streams. However, it is not well understood to what extent Hg transport is associated with suspended sediment versus dissolved organic matter (DOM) during <span class="hlt">snowmelt</span> runoff. To address this question, we sampled the upper Provo River (Utah, USA) during 2015 and 2016 at high frequency during the <span class="hlt">snowmelt</span> season. The Provo River feeds into Jordanelle Reservoir, which has fish consumption advisories due elevated Hg concentrations. Throughout the <span class="hlt">snowmelt</span> season we sampled snow, soil, soil water, and overland flow samples in the upper Provo River watershed. Samples were analyzed for total Hg (THg), methylmercury (MeHg), DOC, and DOM. Preliminary results show THg concentrations exceeding 7 ng/L at maximum stream discharge with the "dissolved" (calculated as filtered/unfiltered concentration) fraction averaging 75%. The dissolved Hg fraction is highly correlated with DOC (R2>0.9), suggesting that Hg transport is dominated by complexation with organic matter. Over 70% of the THg load in the upper Provo River occurred during the <span class="hlt">snowmelt</span> season (May through June) during 2015 and 2016. Fluorescence spectroscopy analyses are underway to determine the type and quality of DOM present and its role in Hg complexation and mobilization. Together these measurements will provide insight into Hg mobilization, bioavailability, and fate during the <span class="hlt">snowmelt</span> season.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AcO....69..129B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AcO....69..129B"><span>Synchronous flowering despite differences in <span class="hlt">snowmelt</span> timing among habitats of Empetrum hermaphroditum</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bienau, Miriam J.; Kröncke, Michael; Eiserhardt, Wolf L.; Otte, Annette; Graae, Bente J.; Hagen, Dagmar; Milbau, Ann; Durka, Walter; Eckstein, R. Lutz</p> <p>2015-11-01</p> <p>The topography within arctic-alpine landscapes is very heterogeneous, resulting in diverse snow distribution patterns, with different <span class="hlt">snowmelt</span> timing in spring. This may influence the phenological development of arctic and alpine plant species and asynchronous flowering may promote adaptation of plants to their local environments. We studied how flowering phenology of the dominant dwarf shrub Empetrum hermaphroditum varied among three habitats (exposed ridges, sheltered depressions and birch forest) differing in winter snow depth and thus <span class="hlt">snowmelt</span> timing in spring, and whether the observed patterns were consistent across three different study areas. Despite significant differences in <span class="hlt">snowmelt</span> timing between habitats, full flowering of E. hermaphroditum was nearly synchronous between the habitats, and implies a high flowering overlap. Our data show that exposed ridges, which had a long lag phase between <span class="hlt">snowmelt</span> and flowering, experienced different temperature and light conditions than the two late melting habitats between <span class="hlt">snowmelt</span> and flowering. Our study demonstrates that small scale variation seems matter less to flowering of Empetrum than interannual differences in <span class="hlt">snowmelt</span> timing.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009AGUFM.U13B0072R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009AGUFM.U13B0072R"><span>Infrastructure Improvements for <span class="hlt">Snowmelt</span> Runoff Forecasting and Assessments of Climate Change Impacts on Water Supplies in the Rio Grande Basin</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rango, A.; Steele, C. M.; Demouche, L.</p> <p>2009-12-01</p> <p>, namely, the Rio Grande near Del Norte, CO and the Rio Hondo, Rio Chama, and Castillo Creek in NM, all tributaries of the Rio Grande basin. An additional 21 sub basins will be added as the development and testing of methods progresses. High spatial resolution Landsat TM data (30 m) are being used to evaluate estimates of snow cover maps from moderate spatial resolution data from Terra MODIS (250m and 500 m). Currently MODIS provides optimal temporal sampling (daily data) but the most effective MODIS-based snow cover mapping method has yet to be determined. We aim to identify the best MODIS snow-mapping algorithm for the Rio Grande area. For the <span class="hlt">snowmelt</span> modeling, we are using an updated revision of SRM which directly accepts remote sensing snow cover inputs but can also automatically assess the climate change effects of future scenarios. The methods under development are intended for operational use by interested water resources agencies. With this end in mind, we will be developing an ArcGIS Toolbox (ESRI) and manual that will incorporate all the tools and instructions necessary for data download, re-projection and formatting, modeling and <span class="hlt">streamflow</span> estimation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014EOSTr..95..288N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014EOSTr..95..288N"><span>Assessing the Vulnerability of Water Supply to Changing <span class="hlt">Streamflow</span> Conditions</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Nazemi, Alireza (Ali); Wheater, Howard S.</p> <p>2014-08-01</p> <p>Natural <span class="hlt">streamflows</span> are major water supplies globally and are sensitive to climate change. This has serious implications for water resource management: While changes in climate perturb water availability, human activities are developed around certain <span class="hlt">streamflow</span> characteristics, such as flow seasonality and volume. Therefore, any shifts in <span class="hlt">streamflow</span> regime can greatly affect human livelihoods.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFM.H51E1232B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFM.H51E1232B"><span>Climate Regime Shifts and <span class="hlt">Streamflow</span> Responses in the Merrimack Watershed, NH-MA</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Berton, R.; Driscoll, C. T.; Chandler, D. G.</p> <p>2013-12-01</p> <p>Climate change has frequently been related to alterations to the hydrologic cycle, especially for sites with winter snowpack and an annual <span class="hlt">snowmelt</span> hydrograph. In the Northeast USA, changes in <span class="hlt">streamflow</span> depend on both advanced timing of melt, typical of the sites with winter dominated precipitation, and increasing summer precipitation. In order to manage various demands for water, planners require robust metrics of change in flow quantity and timing for both wet and dry years. This study seeks appropriate metrics of hydrologic change, at several sites with different stream orders and levels of development within the Merrimack Watershed in the Northeast USA. The term "regime" is defined as variation in a parameter of interest. The regime change is a given expression to changes in statistical properties of data including mean, standard deviation, and skewness. Looking at long-term changes of a hydrological parameter without considering regime changes could result in over- or under-estimating trends. Trend evaluation over similar regime segment could be a more precise approach to study changes in hydroclimatological parameters. Regime shift point detection method developed by (Rodionov, 2004) is a sequential analysis which does not need pre-assumptions about timing of the shifts. The purpose of our research is to find regime shift points in hydroclimatological parameters at the study sites located within the Merrimack Watershed, NH-MA. Analysis of complete and partial annual <span class="hlt">streamflow</span> records, by a combination of hydrologic flow classification (Genz and Luz, 2012) and regime shift point detection (Rodionov, 2004) provides insight into recent changes in <span class="hlt">streamflow</span> regime. We try to identify the correlation between regime shifts in climate indices and observed trends in hydrologic variables in the Merrimack Watershed. The Atlantic Multi-decadal Oscillation (AMO) and the North Atlantic Oscillation (NAO) are the two climate indices related to sea surface temperature</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005WRR....41.7005L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005WRR....41.7005L"><span>Snow-fed <span class="hlt">streamflow</span> timing at different basin scales: Case study of the Tuolumne River above Hetch Hetchy, Yosemite, California</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lundquist, Jessica D.; Dettinger, Michael D.; Cayan, Daniel R.</p> <p>2005-07-01</p> <p>Diurnal cycles in snow-fed streams provide a useful technique for measuring the time it takes water to travel from the top of the snowpack, where <span class="hlt">snowmelt</span> typically peaks in the afternoon, to the river gauge, where the daily maximum flows may arrive many hours later. Hourly stage measurements in nested subbasins (6-775 km2) of the Tuolumne River in Yosemite National Park illustrate travel time delays at different basin scales during the spring 2002 and 2003 melt seasons. Travel times increase with longer percolation times through deeper snowpacks, increase with longer travel times over land and along longer stream channels, and increase with slower in-stream flow velocities. In basins smaller than 30 km2, travel times through the snowpack dominate <span class="hlt">streamflow</span> timing. In particular, daily peak flows shift to earlier in the day as snowpacks thin and mean discharges increase. In basins larger than 200 km2, snowpack heterogeneity causes the hour of peak flow to be highly consistent, with little or no variation as the snowpack thins. Basins with areas in between 30 and 200 km2 exhibit different sequences of diurnal <span class="hlt">streamflow</span> timing in different years, sometimes acting like small basins and other times like large basins. From the start of the melt season until the day of peak <span class="hlt">snowmelt</span> discharge, increasing travel distances in channels as the snow line retreats to higher elevations do not cause long enough travel delays to offset the observed decrease in mean travel times through the snowpack. A model that couples porous medium flow through thinning snowpacks with free surface flow in stream channels can reproduce the observed patterns, provided that the model incorporates snowpack heterogeneity.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70029667','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70029667"><span>Snow-fed <span class="hlt">streamflow</span> timing at different basin scales: Case study of the Tuolumne River above Hetch Hetchy, Yosemite, California</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Lundquist, J.D.; Dettinger, M.D.; Cayan, D.R.</p> <p>2005-01-01</p> <p>Diurnal cycles in snow-fed streams provide a useful technique for measuring the time it takes water to travel from the top of the snowpack, where <span class="hlt">snowmelt</span> typically peaks in the afternoon, to the river gauge, where the daily maximum flows may arrive many hours later. Hourly stage measurements in nested subbasins (6-775 km2) of the Tuolumne River in Yosemite National Park illustrate travel time delays at different basin scales during the spring 2002 and 2003 melt seasons. Travel times increase with longer percolation times through deeper snowpacks, increase with longer travel times over land and along longer stream channels, and increase with slower in-stream flow velocities. In basins smaller than 30 km2, travel times through the snowpack dominate <span class="hlt">streamflow</span> timing. In particular, daily peak flows shift to earlier in the day as snowpacks thin and mean discharges increase. In basins larger than 200 km2, snowpack heterogeneity causes the hour of peak flow to be highly consistent, with little or no variation as the snowpack thins. Basins with areas in between 30 and 200 km2 exhibit different sequences of diurnal <span class="hlt">streamflow</span> timing in different years, sometimes acting like small basins and other times like large basins. From the start of the melt season until the day of peak <span class="hlt">snowmelt</span> discharge, increasing travel distances in channels as the snow line retreats to higher elevations do not cause long enough travel delays to offset the observed decrease in mean travel times through the snowpack. A model that couples porous medium flow through thinning snowpacks with free surface flow in stream channels can reproduce the observed patterns, provided that the model incorporates snowpack heterogeneity. Copyright 2005 by the American Geophysical Union.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.H51T..03B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.H51T..03B"><span>Remote Sensing-based Methodologies for Snow Model Adjustments in Operational <span class="hlt">Streamflow</span> Prediction</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bender, S.; Miller, W. P.; Bernard, B.; Stokes, M.; Oaida, C. M.; Painter, T. H.</p> <p>2015-12-01</p> <p>Water management agencies rely on hydrologic forecasts issued by operational agencies such as NOAA's Colorado Basin River Forecast Center (CBRFC). The CBRFC has partnered with the Jet Propulsion Laboratory (JPL) under funding from NASA to incorporate research-oriented, remotely-sensed snow data into CBRFC operations and to improve the accuracy of CBRFC forecasts. The partnership has yielded valuable analysis of snow surface albedo as represented in JPL's MODIS Dust Radiative Forcing in Snow (MODDRFS) data, across the CBRFC's area of responsibility. When dust layers within a snowpack emerge, reducing the snow surface albedo, the <span class="hlt">snowmelt</span> rate may accelerate. The CBRFC operational snow model (SNOW17) is a temperature-index model that lacks explicit representation of snowpack surface albedo. CBRFC forecasters monitor MODDRFS data for emerging dust layers and may manually adjust SNOW17 melt rates. A technique was needed for efficient and objective incorporation of the MODDRFS data into SNOW17. Initial development focused in Colorado, where dust-on-snow events frequently occur. CBRFC forecasters used retrospective JPL-CBRFC analysis and developed a quantitative relationship between MODDRFS data and mean areal temperature (MAT) data. The relationship was used to generate adjusted, MODDRFS-informed input for SNOW17. Impacts of the MODDRFS-SNOW17 MAT adjustment method on <span class="hlt">snowmelt</span>-driven <span class="hlt">streamflow</span> prediction varied spatially and with characteristics of the dust deposition events. The largest improvements occurred in southwestern Colorado, in years with intense dust deposition events. Application of the method in other regions of Colorado and in "low dust" years resulted in minimal impact. The MODDRFS-SNOW17 MAT technique will be implemented in CBRFC operations in late 2015, prior to spring 2016 runoff. Collaborative investigation of remote sensing-based adjustment methods for the CBRFC operational hydrologic forecasting environment will continue over the next several years.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004HyPr...18.3371S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004HyPr...18.3371S"><span>Incorporating topographic variability into a simple regional <span class="hlt">snowmelt</span> model</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sloan, W. T.; Kilsby, C. G.; Lunn, R.</p> <p>2004-12-01</p> <p>General circulation models (GCMs), or stand-alone models that are forced by the output from GCMs, are increasingly being used to simulate the interactions between snow cover, <span class="hlt">snowmelt</span>, climate and water resources. The variation in snowpack extent, and hence albedo, through time in a cell is likely to be substantial, especially in mid-latitude mountainous regions. As a consequence, the energy budget simulation by a GCM relies on a realistic representation of snowpack extent. Similarly, from a water resource perspective, the spatial extent of the pack is key in predicting meltwater discharges into rivers. In this paper a simple computationally efficient regional snow model has been developed, which is based on a degree-day approach and simulates the fraction of the model domain covered by snow, the spatially averaged melt rate and the mean snowpack depth. Computational efficiency is achieved through a novel spatial averaging procedure, which relies on the assumptions that precipitation and temperature scale linearly with elevation and that the distribution of elevations in the domain can be modelled by a continuous function. The resulting spatially averaged model is compared with both observations of the duration of snow cover throughout Austria and with results from a distributed model based on the same underlying assumptions but applied at a fine spatial resolution. The new spatially averaged model successfully simulated the seasonal snow duration observations and reproduced the daily dynamics of snow cover extent, the spatially averaged melt rate and mean pack depth simulated by the distributed model. It, therefore, offers a computationally efficient and easily applied alternative to the current crop of regional snow models.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li class="active"><span>15</span></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_15 --> <div id="page_16" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li class="active"><span>16</span></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="301"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.usgs.gov/circ/1376/pdf/circ1376_barlow_report_508.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/circ/1376/pdf/circ1376_barlow_report_508.pdf"><span><span class="hlt">Streamflow</span> depletion by wells--Understanding and managing the effects of groundwater pumping on <span class="hlt">streamflow</span></span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Barlow, Paul M.; Leake, Stanley A.</p> <p>2012-11-02</p> <p>Groundwater is an important source of water for many human needs, including public supply, agriculture, and industry. With the development of any natural resource, however, adverse consequences may be associated with its use. One of the primary concerns related to the development of groundwater resources is the effect of groundwater pumping on <span class="hlt">streamflow</span>. Groundwater and surface-water systems are connected, and groundwater discharge is often a substantial component of the total flow of a stream. Groundwater pumping reduces the amount of groundwater that flows to streams and, in some cases, can draw <span class="hlt">streamflow</span> into the underlying groundwater system. <span class="hlt">Streamflow</span> reductions (or depletions) caused by pumping have become an important water-resource management issue because of the negative impacts that reduced flows can have on aquatic ecosystems, the availability of surface water, and the quality and aesthetic value of streams and rivers. Scientific research over the past seven decades has made important contributions to the basic understanding of the processes and factors that affect <span class="hlt">streamflow</span> depletion by wells. Moreover, advances in methods for simulating groundwater systems with computer models provide powerful tools for estimating the rates, locations, and timing of <span class="hlt">streamflow</span> depletion in response to groundwater pumping and for evaluating alternative approaches for managing <span class="hlt">streamflow</span> depletion. The primary objective of this report is to summarize these scientific insights and to describe the various field methods and modeling approaches that can be used to understand and manage <span class="hlt">streamflow</span> depletion. A secondary objective is to highlight several misconceptions concerning <span class="hlt">streamflow</span> depletion and to explain why these misconceptions are incorrect.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.fs.usda.gov/treesearch/pubs/13000','TREESEARCH'); return false;" href="https://www.fs.usda.gov/treesearch/pubs/13000"><span><span class="hlt">Streamflow</span> response from an ombrotrophic mire</span></a></p> <p><a target="_blank" href="http://www.fs.usda.gov/treesearch/">Treesearch</a></p> <p>E.S. Verry; K.N. Brooks; P.K. Barten</p> <p>1988-01-01</p> <p><span class="hlt">Streamflow</span> response to a rainstorm exceeding a 100-year return interval is documented in relation to the peat profile and microtopography. The water tab1e:discharge relation is corrected for specific yield and found to closely parallel the stage:discharge relationship for a level reservoir for flows up to a 25-year return interval. A faster water table:discharge...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.usgs.gov/of/1970/0025/report.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/of/1970/0025/report.pdf"><span>A proposed <span class="hlt">streamflow</span> data program for Michigan</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Bent, P.C.</p> <p>1970-01-01</p> <p>An evaluation of the <span class="hlt">streamflow</span> data available in Michigan was made to provide guidelines for planning future water resource programs. The basic steps in the evaluation procedure were (1) definition of the long-term goals of the <span class="hlt">streamflow</span> data program in quantitative form, (2) examination and analysis of all available data to determine which goals have already been met, and (3) consideration of alternate programs and techniques to meet the remaining objectives. It was found that most goals could not be met by regionalization of the data for gaged basins by regression analysis. This fact indicates that few changes can be made in the present program on the basis of computing data by regression formulas. However, regression formulas that include factors not evaluated as a part of this study, may provide a basis for regional <span class="hlt">streamflow</span> analysis. The evaluation indicated that some changes in the streamgaging network can be made on the basis of length of records already collected. A <span class="hlt">streamflow</span> data program based on the guidelines developed in this rstudy is proposed for the future.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.H13C1534A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.H13C1534A"><span>HYDRORECESSION: A toolbox for <span class="hlt">streamflow</span> recession analysis</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Arciniega, S.</p> <p>2015-12-01</p> <p><span class="hlt">Streamflow</span> recession curves are hydrological signatures allowing to study the relationship between groundwater storage and baseflow and/or low flows at the catchment scale. Recent studies have showed that <span class="hlt">streamflow</span> recession analysis can be quite sensitive to the combination of different models, extraction techniques and parameter estimation methods. In order to better characterize <span class="hlt">streamflow</span> recession curves, new methodologies combining multiple approaches have been recommended. The HYDRORECESSION toolbox, presented here, is a Matlab graphical user interface developed to analyse <span class="hlt">streamflow</span> recession time series with the support of different tools allowing to parameterize linear and nonlinear storage-outflow relationships through four of the most useful recession models (Maillet, Boussinesq, Coutagne and Wittenberg). The toolbox includes four parameter-fitting techniques (linear regression, lower envelope, data binning and mean squared error) and three different methods to extract hydrograph recessions segments (Vogel, Brutsaert and Aksoy). In addition, the toolbox has a module that separates the baseflow component from the observed hydrograph using the inverse reservoir algorithm. Potential applications provided by HYDRORECESSION include model parameter analysis, hydrological regionalization and classification, baseflow index estimates, catchment-scale recharge and low-flows modelling, among others. HYDRORECESSION is freely available for non-commercial and academic purposes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.H51N1588B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.H51N1588B"><span>The Probability Distribution of Daily <span class="hlt">Streamflow</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Blum, A.; Vogel, R. M.</p> <p>2015-12-01</p> <p>Flow duration curves (FDCs) are a graphical illustration of the cumulative distribution of <span class="hlt">streamflow</span>. Daily <span class="hlt">streamflows</span> often range over many orders of magnitude, making it extremely challenging to find a probability distribution function (pdf) which can mimic the steady state or period of record FDC (POR-FDC). Median annual FDCs (MA-FDCs) describe the pdf of daily <span class="hlt">streamflow</span> in a typical year. For POR- and MA-FDCs, Lmoment diagrams, visual assessments of FDCs and Quantile-Quantile probability plot correlation coefficients are used to evaluate goodness of fit (GOF) of candidate probability distributions. FDCs reveal that both four-parameter kappa (KAP) and three-parameter generalized Pareto (GP3) models result in very high GOF for the MA-FDC and a relatively lower GOF for POR-FDCs at over 500 rivers across the coterminous U.S. Physical basin characteristics, such as baseflow index as well as hydroclimatic indices such as the aridity index and the runoff ratio are found to be correlated with one of the shape parameters (kappa) of the KAP and GP3 pdfs. Our work also reveals several important areas for future research including improved parameter estimators for the KAP pdf, as well as increasing our understanding of the conditions which give rise to improved GOF of analytical pdfs to large samples of daily <span class="hlt">streamflows</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.H21L..06J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.H21L..06J"><span><span class="hlt">Streamflow</span> life cycles spanning the USA</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jasechko, S.; McDonnell, J.; Welker, J. M.</p> <p>2014-12-01</p> <p>Rivers are replenished by precipitation that works its way through watersheds and into stream networks. The time that precipitation requires to travel into a stream regulates contaminant transports, nutrient mobility and bedrock weathering, but has not yet been evaluated at a continental scale. Here we synthesize a pan-U.S.A. dataset of rain, snow and <span class="hlt">streamflow</span> 18O/16O and 2H/1H ratios and analyze the data to show that the lion's share of USA <span class="hlt">streamflow</span> is generated by precipitation that takes ~2 months to ~2.5 years to flush through watersheds and into networks of streams (i.e., rivers replenished by "infant-to-toddler aged" precipitation). These <span class="hlt">streamflow</span> ages are considerably shorter than the average amount of time that water spends within streams themselves (~1 month, globally), and much shorter than the global groundwater residence time of more than ~1000 years. We also estimate the depth of "dynamic" groundwater storage that actively generates the majority of <span class="hlt">streamflow</span> and discover that less than ~1% of watershed flowpaths generate the bulk of continental runoff. Our finding showcases that the most hydrologically-active zone within Earth's hydrosphere is located nearest to the surface where atmosphere-biosphere-lithosphere interactions are at a maximum. This research emphasizes the importance of critical zone research for developing accurate forecasts of how human modifications to the land and climate will impact downstream water, nutrient and contaminant fluxes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012PhDT........98T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012PhDT........98T"><span>Rainfall and <span class="hlt">Streamflow</span> Variability in Ghana</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tanu, Michael M.</p> <p></p> <p>The objective of this research is to investigate the variability of rainfall and <span class="hlt">streamflow</span> over Ghana. Analyses of rainfall shows larger daily variability and maxima amounts in the southern coastal belt than in either the middle or northern parts of the country. The high variability in rainfall at the coast is associated with sea surface temperatures (SSTs) changes over the Guinea coast. This is related to the evolution of the cold tongue over the Atlantic during the rainfall season. The results indicate that the extreme rainfall events occur as single events, but there are occasions when they occur sequentially, and some of these events could continue for more than 5 days. We note that the average SSTs over the equatorial Atlantic favor the occurrence of extreme rainfall over the coastal and middle belt, while relatively cold SSTs favor the occurrence of extreme rainfall events in the northern belt. This study also shows the presence of eastward moving convective signals which are associated with Kelvin waves that impact the rainfall in spring over Ghana. Kelvin waves account for ~70% of the extreme rainfall events during boreal spring compared to 25%-35% in summer. The reason for this is that the rainfall in southern Ghana peaks in spring when the frequency of propagation of these waves is the highest. Analysis of <span class="hlt">streamflow</span> and rainfall suggested that both rainfall and <span class="hlt">streamflow</span> exhibit a bimodal pattern. Although the peak in rainfall occurs during the major season, the peak in <span class="hlt">streamflow</span> occurs during the minor season. Extreme rainfall events are more associated with flooding in the rivers than continuous non-extreme rainfall events. Additionally, we note a decreasing trend in rainfall and <span class="hlt">streamflow</span> over the southern part of Ghana. But, the decrease in <span class="hlt">streamflow</span> is larger than for the rainfall. It is to be noted, however, that the draw of water from the two rivers by the communities for domestic and irrigation use are very difficult to quantify and could be</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70021284','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70021284"><span>Seasonal change in precipitation, snowpack, <span class="hlt">snowmelt</span>, soil water and streamwater chemistry, northern Michigan</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Stottlemyer, R.; Toczydlowski, D.</p> <p>1999-01-01</p> <p>We have studied weekly precipitation, snowpack, <span class="hlt">snowmelt</span>, soil water and streamwater chemistry throughout winter for over a decade in a small (176 ha) northern Michigan watershed with high snowfall and vegetated by 60 to 80 year-old northern hardwoods. In this paper, we examine physical, chemical, and biological processes responsible for observed seasonal change in streamwater chemistry based upon intensive study during winter 1996-1997. The objective was to define the contributions made to winter and spring streamwater chemical concentration and flux by processes as <span class="hlt">snowmelt</span>, over-winter forest floor and surface soil mineralization, immobilization, and exchange, and subsurface flowpath. The forest floor and soil were unfrozen beneath the snowpack which permitted most <span class="hlt">snowmelt</span> to enter. Over-winter soil mineralization and other biological processes maintain shallow subsurface ion and dissolved organic carbon (DOC) reservoirs. Small, but steady, <span class="hlt">snowmelt</span> throughout winter removed readily mobilized soil NO3- which resulted in high over-winter streamwater concentrations but little flux. Winter soil water levels and flowpaths were generally deep which increased soil water and streamwater base cation (C(B)), HCO3-, and Si concentrations. Spring <span class="hlt">snowmelt</span> increased soil water levels and removal of ions and DOC from the biologically active forest floor and shallow soils. The snowpack solute content was a minor component in determining streamwater ion concentration or flux during and following peak <span class="hlt">snowmelt</span>. Exchangeable ions, weakly adsorbed anions, and DOC in the forest floor and surface soils dominated the chemical concentration and flux in soil water and streamwater. Following peak <span class="hlt">snowmelt</span>, soil microbial immobilization and rapidly increased plant uptake of limiting nutrients removed nearly all available nitrogen from soil water and streamwater. During the growing season high evapotranspiration increased subsurface flowpath depth which in turn removed weathering</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.usgs.gov/wri/1993/4132/report.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/wri/1993/4132/report.pdf"><span>Variability of <span class="hlt">streamflow</span> and precipitation in Washington</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Kresch, D.L.</p> <p>1994-01-01</p> <p>Patterns of variation in monthly records of 55 <span class="hlt">streamflow</span> stations and 38 precipitation stations were evaluated using chronologies of cumulative departure of monthly values from mean-monthly values. The cumulative departures for each station were rescaled (standardized) by dividng them by the standard deviation of the annual values for that station. The degree of similarity between the chronologies for each pair of either <span class="hlt">streamflow</span> or precipitation stations was measured by the coefficient of correlation between them. Matrices of these coefficients of correlation were evaluated using cluster analysis to identify regions of similarity among the chronologies. The cluster analysis of the <span class="hlt">streamflow</span>-station matrix defined geographic regions of similarity in south- western, northwestern, and northeastern Washington. The cluster analysis of the precipitation-station matrix defined two regions of similarity--western and eastern Washington-- and indicated that there is a tendency for persistent periods of above-average precipitation in western Washington to correspond with persistent periods of below-average precipitation in eastern Washington, and conversely. A water- resource availability index was developed that provides a quantitative interpretation of present conditions in the context of historical records of <span class="hlt">streamflow</span> and precipitation. The index value for a given month and year is calculated as the summation of time-weighted, rescaled, monthly departures during the preceding 3-year period. Methods were described for the use of chronologies of cumulative departure (1) in estimating monthly <span class="hlt">streamflow</span> or precipitation values for ungaged sites from monthly values for gaged sites, and (2) in examining the adequacy of the sizes of existing or proposed reservoirs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014JHyd..511...72S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014JHyd..511...72S"><span>Monthly <span class="hlt">streamflow</span> forecasting using Gaussian Process Regression</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sun, Alexander Y.; Wang, Dingbao; Xu, Xianli</p> <p>2014-04-01</p> <p><span class="hlt">Streamflow</span> forecasting plays a critical role in nearly all aspects of water resources planning and management. In this work, Gaussian Process Regression (GPR), an effective kernel-based machine learning algorithm, is applied to probabilistic <span class="hlt">streamflow</span> forecasting. GPR is built on Gaussian process, which is a stochastic process that generalizes multivariate Gaussian distribution to infinite-dimensional space such that distributions over function values can be defined. The GPR algorithm provides a tractable and flexible hierarchical Bayesian framework for inferring the posterior distribution of <span class="hlt">streamflows</span>. The prediction skill of the algorithm is tested for one-month-ahead prediction using the MOPEX database, which includes long-term hydrometeorological time series collected from 438 basins across the U.S. from 1948 to 2003. Comparisons with linear regression and artificial neural network models indicate that GPR outperforms both regression methods in most cases. The GPR prediction of MOPEX basins is further examined using the Budyko framework, which helps to reveal the close relationships among water-energy partitions, hydrologic similarity, and predictability. Flow regime modification and the resulting loss of predictability have been a major concern in recent years because of climate change and anthropogenic activities. The persistence of <span class="hlt">streamflow</span> predictability is thus examined by extending the original MOPEX data records to 2012. Results indicate relatively strong persistence of <span class="hlt">streamflow</span> predictability in the extended period, although the low-predictability basins tend to show more variations. Because many low-predictability basins are located in regions experiencing fast growth of human activities, the significance of sustainable development and water resources management can be even greater for those regions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFMGC41H..02Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFMGC41H..02Y"><span>Deciduous trees are a large and overlooked sink for <span class="hlt">snowmelt</span> water in the boreal forest</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Young-Robertson, J. M.; Bolton, W. R.; Bhatt, U. S.; Cristobal, J.; Thoman, R.</p> <p>2016-12-01</p> <p>The terrestrial water cycle contains large uncertainties that impact our understanding of water budgets and climate dynamics. Water storage is a key uncertainty in the boreal water budget, with tree water storage often ignored. The goal of this study is to quantify tree water content during the <span class="hlt">snowmelt</span> and growing season periods for Alaskan and western Canadian boreal forests. We conducted a two year field study utilizing time domain reflectometry to measure tree water content in deciduous and coniferous trees in a watershed in Interior Alaska's boreal forest. Deciduous trees reached saturation between <span class="hlt">snowmelt</span> and leaf-out, taking up 21-25% of the available <span class="hlt">snowmelt</span> water, while coniferous trees removed <1%. We found that deciduous trees removed 17.8-20.9 billion m3 of <span class="hlt">snowmelt</span> water, which is equivalent to 8.7-10.2% of the Yukon River's annual discharge. Deciduous trees transpired 2-12% (0.4-2.2 billion m3) of the absorbed <span class="hlt">snowmelt</span> water immediately after leaf-out, increasing favorable conditions for atmospheric convection, and an additional 10-30% (2.0-5.2 billion m3) between leaf-out and mid-summer. By 2100, boreal deciduous tree area is expected to increase by 1-15%, potentially resulting in an additional 0.3-3 billion m3 of <span class="hlt">snowmelt</span> water removed from the soil per year. This study is the first to show that deciduous tree water uptake of <span class="hlt">snowmelt</span> water represents a large but overlooked aspect of the water balance in boreal watersheds.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..18.4536D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..18.4536D"><span>5 years of continuous seismic monitoring of <span class="hlt">snowmelt</span> cycles in a Pyrenean valley</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Diaz, Jordi; Sánchez-Pastor, Pilar; Gallart, Josep</p> <p>2016-04-01</p> <p>In recent years the analysis of background seismic noise variations in the proximity of river channels has revealed as a useful tool to monitor river flow, even for modest discharges. We will focus here in the application of this methodology to study the <span class="hlt">snowmelt</span> cycle in an Pyrenean valley during the last 5 years, using data from the seismic geophysical station located inside the Canfranc Underground Laboratory (Central Pyrenees). Diaz et al. (2014) first identified in the seismic data the signature of river flow increases associated to <span class="hlt">snowmelt</span> episodes in the catchment area of the Aragon River, based on the marked correlation between the seismic energy variations in the 2-8 Hz frequency band and the estimated variations in water resources from snowfall. The analysis of seismic data during the <span class="hlt">snowmelt</span> periods allows to identify a clear 24h cycle, with energy increasing from about 14:00 GMT, remaining at a relatively high level for 12 hours and then smoothly vanishing. The spectrogram reveals richer information, as clear variations in the frequency content can be detected during the time intervals in which the amplitude of the seismic signal remains constant. The data available so far allow to compare the evolution of <span class="hlt">snowmelt</span> in five seasons with very different hydrological behavior. The 2011 and 2012 seasons have been dry, with snow volumes 30-50 % beneath the average values, while the 2013, 2014 and in particular the 2015 seasons have been largely above the mean. Those variations are reflected in the seismic data, which allow to monitor the time occurrence of the main <span class="hlt">snowmelt</span> stages for each season and to estimate the intensity of the different <span class="hlt">snowmelt</span> episodes. Therefore, seismic data can be useful for long term monitoring of <span class="hlt">snowmelt</span> in Alpine-style mountains.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFM.H43G1525D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFM.H43G1525D"><span>Disentangling the response of <span class="hlt">streamflow</span> to forest management and climate</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dymond, S.; Miniat, C.; Bladon, K. D.; Keppeler, E.; Caldwell, P. V.</p> <p>2016-12-01</p> <p>Paired watershed studies have showcased the relationships between forests, management, and <span class="hlt">streamflow</span>. However, classical analyses of paired-watershed studies have done little to disentangle the effects of management from overarching climatic signals, potentially masking the interaction between management and climate. Such approaches may confound our understanding of how forest management impacts <span class="hlt">streamflow</span>. Here we use a 50-year record of <span class="hlt">streamflow</span> and climate data from the Caspar Creek Experimental Watersheds (CCEW), California, USA to separate the effects of forest management and climate on <span class="hlt">streamflow</span>. CCEW has two treatment watersheds that have been harvested in the past 50 years. We used a nonlinear mixed model to combine the pre-treatment relationship between <span class="hlt">streamflow</span> and climate and the post-treatment relationship via an interaction between climate and management into one equation. Our results show that precipitation and potential evapotranspiration alone can account for >95% of the variability in pre-treatment <span class="hlt">streamflow</span>. Including management scenarios into the model explained most of the variability in <span class="hlt">streamflow</span> (R2 > 0.98). While forest harvesting altered <span class="hlt">streamflow</span> in both of our modeled watersheds, removing 66% of the vegetation via selection logging using a tractor yarding system over the entire watershed had a more substantial impact on <span class="hlt">streamflow</span> than clearcutting small portions of a watershed using cable-yarding. These results suggest that forest harvesting may result in differing impacts on <span class="hlt">streamflow</span> and highlights the need to incorporate climate into <span class="hlt">streamflow</span> analyses of paired-watershed studies.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20120015430','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20120015430"><span>Distributed Assimilation of Satellite-based Snow Extent for Improving Simulated <span class="hlt">Streamflow</span> in Mountainous, Dense Forests: An Example Over the DMIP2 Western Basins</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Yatheendradas, Soni; Peters-Lidard, Christa D.; Koren, Victor; Cosgrove, Brian A.; DeGoncalves, Luis G. D.; Smith, Michael; Geiger, James; Cui, Zhengtao; Borak, Jordan; Kumar, Sujay V.; Riggs, George; Mizukami, Naoki</p> <p>2012-01-01</p> <p>Snow cover area affects <span class="hlt">snowmelt</span>, soil moisture, evapotranspiration, and ultimately <span class="hlt">streamflow</span>. For the Distributed Model Intercomparison Project - Phase 2 Western basins, we assimilate satellite-based fractional snow cover area (fSCA) from the Moderate Resolution Imaging Spectroradiometer, or MODIS, into the National Weather Service (NWS) SNOW-17 model. This model is coupled with the NWS Sacramento Heat Transfer (SAC-HT) model inside the National Aeronautics and Space Administration's (NASA) Land Information System. SNOW-17 computes fSCA from snow water equivalent (SWE) values using an areal depletion curve. Using a direct insertion, we assimilate fSCAs in two fully distributed ways: 1) we update the curve by attempting SWE preservation, and 2) we reconstruct SWEs using the curve. The preceding are refinements of an existing simple, conceptually-guided NWS algorithm. Satellite fSCA over dense forests inadequately accounts for below-canopy snow, degrading simulated <span class="hlt">streamflow</span> upon assimilation during <span class="hlt">snowmelt</span>. Accordingly, we implement a below-canopy allowance during assimilation. This simplistic allowance and direct insertion are found to be inadequate for improving calibrated results, still degrading them as mentioned above. However, for <span class="hlt">streamflow</span> volume for the uncalibrated runs, we obtain: (1) substantial to major improvements (64-81 %) as a percentage of the control run residuals (or distance from observations), and (2) minor improvements (16-22 %) as a percentage of observed values. We highlight the need for detailed representations of canopy-snow optical radiative transfer processes in mountainous, dense forest regions if assimilation-based improvements are to be seen in calibrated runs over these areas.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012WRR....48.9557Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012WRR....48.9557Y"><span>Distributed assimilation of satellite-based snow extent for improving simulated <span class="hlt">streamflow</span> in mountainous, dense forests: An example over the DMIP2 western basins</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yatheendradas, Soni; Lidard, Christa D. Peters; Koren, Victor; Cosgrove, Brian A.; de Goncalves, Luis G. G.; Smith, Michael; Geiger, Jim; Cui, Zhengtao; Borak, Jordan; Kumar, Sujay V.; Toll, David L.; Riggs, George; Mizukami, Naoki</p> <p>2012-09-01</p> <p>Snow cover area affects <span class="hlt">snowmelt</span>, soil moisture, evapotranspiration, and ultimately <span class="hlt">streamflow</span>. For the Distributed Model Intercomparison Project - Phase 2 Western basins, we assimilate satellite-based fractional snow cover area (fSCA) from the Moderate Resolution Imaging Spectroradiometer, or MODIS, into the National Weather Service (NWS) SNOW-17 model. This model is coupled with the NWS Sacramento Heat Transfer (SAC-HT) model inside the National Aeronautics and Space Administration's (NASA) Land Information System. SNOW-17 computes fSCA from snow water equivalent (SWE) values using an areal depletion curve. Using a direct insertion, we assimilate fSCAs in two fully distributed ways: (1) we update the curve by attempting SWE preservation, and (2) we reconstruct SWEs using the curve. The preceding are refinements of an existing simple, conceptually guided NWS algorithm. Satellite fSCA over dense forests inadequately accounts for below-canopy snow, degrading simulated <span class="hlt">streamflow</span> upon assimilation during <span class="hlt">snowmelt</span>. Accordingly, we implement a below-canopy allowance during assimilation. This simplistic allowance and direct insertion are found to be inadequate for improving calibrated results, still degrading them as mentioned above. However, for <span class="hlt">streamflow</span> volume for the uncalibrated runs, we obtain: (1) substantial to major improvements (64-81%) as a percentage of the control run residuals (or distance from observations), and (2) minor improvements (16-22%) as a percentage of observed values. We highlight the need for detailed representations of canopy-snow optical radiative transfer processes in mountainous, dense forest regions if assimilation-based improvements are to be seen in calibrated runs over these areas.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015PhDT.......187P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015PhDT.......187P"><span>The impact of black carbon deposition on snowpack and <span class="hlt">streamflow</span> in the Wasatch mountains in Utah: A study using MODIS albedo data, statistical modeling and machine learning</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Panthail, Jai Kanth</p> <p></p> <p>Salt Lake City, located at the base of the Wasatch mountain range in Utah, receives a majority of its potable water from a system of mountain creeks. <span class="hlt">Snowmelt</span> runoff from mountain watersheds provides the city a clean and relatively inexpensive water supply, and has been a key driver in the city's growth and prosperity. There has been keen interest recently on the possible impact of the deposition of darkening matter, such as dust and black carbon (BC) on the snow, which might lead to a decrease in its 'albedo' or reflective capacity. Such a decrease is expected to result in faster melting of the snow, shifting springtime <span class="hlt">streamflows</span> to winter. This study aimed to develop a modeling framework to estimate the impact on <span class="hlt">snowmelt</span>-driven runoff due to various BC deposition scenarios. An albedo simulation model, Snow, Ice, and Aerosol Radiation (SNICAR) model, was used to understand the evolution of albedo under different BC loadings. An Albedo-Snow Water Equivalent (A-SWE) model was developed using a machine learning technique, 'Random Forests', to quantify the effect on the state of snowpack under various albedo-change scenarios. An Albedo-Snow Water Equivalent-<span class="hlt">Streamflow</span> (A-SWE-S) model was designed using an advanced statistical modeling technique, 'Generalized Additive Models (GAMs)', to extend the analysis to <span class="hlt">streamflow</span> variations. All models were tested and validated using robust k-fold cross-validation. Albedo data were obtained from NASA's MODIS satellite platform. The key results found the snowpack to be depleted 2-3 weeks later with an albedo increase between 5-10% above current conditions, and 1-2 weeks earlier under albedo decrease of 5-10% below current conditions. Future work will involve improving the A-SWE-S model by better accounting for lagged effects, and the use of results from both models in a city-wide systems model to understand water supply reliability under combined deposition and climate change scenarios.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFM.H42A..05M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFM.H42A..05M"><span>Estimation of <span class="hlt">streamflow</span> response to wildfire and salvage logging in a snow-dominated catchment using a model-based change detection approach</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Moore, R. D.; Mahrlein, M.; Chuang, Y. C. M.</p> <p>2016-12-01</p> <p>Forest cover changes associated with natural disturbance and forest management can have significant influences on the magnitude and timing of <span class="hlt">streamflow</span>. This study quantified the effect of a wildfire that burned over 60% of the catchment of Fishtrap Creek in the southern interior of British Columbia in August 2003. Fishtrap Creek has been gauged from 1970 to present. The catchment drains 158 km2 at the gauging station and has a snow-dominated hydrologic regime. In 2006, about one-third of the burned area was salvage logged. A semi-distributed hydrologic model was calibrated and tested using the pre-fire <span class="hlt">streamflow</span> data. Simulated daily <span class="hlt">streamflow</span> based on the "best" parameter set, and assuming pre-fire forest cover, was used as a "virtual" control in a paired-catchment analysis. Each year was divided into 73 five-day periods (pentads), and separate pre-fire regressions were fit for each of the 73 pentad time series. This approach avoids issues with autocorrelation and can address seasonally varying model bias. Statistically significant increases in <span class="hlt">streamflow</span> were detected in late winter and through the month of April, with no evidence for increased peak flows, which is inferred to reflect a de-synchronization of <span class="hlt">snowmelt</span> between disturbed and undisturbed areas of the catchment. The results of the model-based change detection are consistent with statistical analyses using climatic variables as covariates, but have the advantage of providing more temporal detail. However, the power of the change detection can be limited by insufficiently long records of <span class="hlt">streamflow</span> and driving weather variables for both the pre- and post-fire periods and model structural errors (e.g., an inability to reproduce winter baseflow). An interesting side result of the study was the identification of parameter uncertainty associated with uncertainty regarding forest cover during the calibration period.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.usgs.gov/of/2001/ofr-01-0059/','USGSPUBS'); return false;" href="https://pubs.usgs.gov/of/2001/ofr-01-0059/"><span>Geochemical baseline studies and relations between water quality and <span class="hlt">streamflow</span> in the upper Blackfoot Watershed, Montana: data for July 1997-December 1998</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Nagorski, Sonia A.; Moore, Johnnie N.; Smith, David B.</p> <p>2001-01-01</p> <p>We used ultraclean sampling techniques to study the solute (operationally defined as <0.2 ?m) surface water geochemistry at five sites along the Upper Blackfoot River and four sites along the Landers Fork, some in more detail and more regularly than others. We collected samples also from Hogum Creek, a tributary to the Blackfoot, from Copper Creek, a tributary to the Landers Fork, and from ground water seeps contributing to the flow along the Landers Fork. To better define the physical dynamics of the hydrologic system and to determine geochemical loads, we measured <span class="hlt">streamflow</span> at all the sites where we took samples for water quality analysis. The Upper Blackfoot River, which drains historic mines ca. 20 Km upstream of the study area, had higher trace metal concentrations than did the Landers Fork, which drains the pristine Scapegoat Wilderness area. In both rivers, many of the major elements were inversely related to <span class="hlt">streamflow</span>, and at some sites, several show a hysteresis effect in which the concentrations were lower on the rising limb of the hydrograph than on the falling limb. However, many of the trace elements followed far more irregular trends, especially in the Blackfoot River. Elements such as As, Cu, Fe, Mn, S, and Zn exhibited complex and variable temporal patterns, which included almost no response to <span class="hlt">streamflow</span> differences, increased concentrations following a summer storm and at the start of <span class="hlt">snowmelt</span> in the spring, and/or increased concentrations throughout the course of spring runoff. In summary, complex interactions between the timing and magnitude of <span class="hlt">streamflow</span> with physical and chemical processes within the watershed appeared to greatly influence the geochemistry at the sites, and <span class="hlt">streamflow</span> values alone were not good predictors of solute concentrations in the rivers.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.usgs.gov/wri/1992/4099/report.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/wri/1992/4099/report.pdf"><span>Estimation of Median <span class="hlt">Streamflows</span> at Perennial Stream Sites in Hawaii</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Fontaine, Richard A.; Wong, Michael F.; Matsuoka, Iwao</p> <p>1992-01-01</p> <p>The most accurate estimates of median <span class="hlt">streamflows</span> at perennial stream sites in Hawaii are those made at <span class="hlt">streamflow</span>-gaging stations. Two alternative methods for estimating median <span class="hlt">streamflows</span> at ungaged sites are described in this report. Multiple-regression equations were developed for estimating median <span class="hlt">streamflows</span> at ungaged, unregulated, perennial stream sites. The equations relate combinations of drainage area, mean altitude of the main stream channel, and mean annual precipitation to median <span class="hlt">streamflow</span>. <span class="hlt">Streamflow</span> data from 56 long-term continuous-record gaging stations were used in the analysis. Median-<span class="hlt">streamflow</span> data for all 56 sites were adjusted using record-extension techniques to reflect base period (1912 through 1986) conditions. Hawaii was subdivided into two geographic groups and multiple-regression equations were developed for each. The standard error of predication for the equation developed for the first group, the islands of Oahu, Molokai, and Hawaii, is 41 percent. The standard error of predication for the equation developed for the second group, the islands of Kauai and Maui, is 54 percent. A method for estimating median-<span class="hlt">streamflow</span>, based on discharge measurements and data from nearby <span class="hlt">streamflow</span>-gaging stations, was also developed for 27 regulated, perennial windward Oahu sites. Standard errors of prediction for 23 of the sites range from 5 to 34 percent. Median-<span class="hlt">streamflow</span> estimates for the four remaining sites were considered poor and no measures of accuracy are provided. Discharge measurements can be used to make estimates of median <span class="hlt">streamflows</span> at ungaged, regulated sites where the regression equations developed in this report are not applicable. Discharge measurements can also be used to make estimates of median <span class="hlt">streamflows</span> at ungaged, unregulated sites. Estimates of median <span class="hlt">streamflows</span> based on discharge measurements have greater standard errors than estimates based on continuous <span class="hlt">streamflow</span> records and in general have smaller standard errors</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JHyd..542..125A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JHyd..542..125A"><span>Evaluation of climate modeling factors impacting the variance of <span class="hlt">streamflow</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Al Aamery, N.; Fox, J. F.; Snyder, M.</p> <p>2016-11-01</p> <p>The present contribution quantifies the relative importance of climate modeling factors and chosen response variables upon controlling the variance of <span class="hlt">streamflow</span> forecasted with global climate model (GCM) projections, which has not been attempted in previous literature to our knowledge. We designed an experiment that varied climate modeling factors, including GCM type, project phase, emission scenario, downscaling method, and bias correction. The <span class="hlt">streamflow</span> response variable was also varied and included forecasted <span class="hlt">streamflow</span> and difference in forecast and hindcast <span class="hlt">streamflow</span> predictions. GCM results and the Soil Water Assessment Tool (SWAT) were used to predict <span class="hlt">streamflow</span> for a wet, temperate watershed in central Kentucky USA. After calibrating the <span class="hlt">streamflow</span> model, 112 climate realizations were simulated within the <span class="hlt">streamflow</span> model and then analyzed on a monthly basis using analysis of variance. Analysis of variance results indicate that the difference in forecast and hindcast <span class="hlt">streamflow</span> predictions is a function of GCM type, climate model project phase, and downscaling approach. The prediction of forecasted <span class="hlt">streamflow</span> is a function of GCM type, project phase, downscaling method, emission scenario, and bias correction method. The results indicate the relative importance of the five climate modeling factors when designing <span class="hlt">streamflow</span> prediction ensembles and quantify the reduction in uncertainty associated with coupling the climate results with the hydrologic model when subtracting the hindcast simulations. Thereafter, analysis of <span class="hlt">streamflow</span> prediction ensembles with different numbers of realizations show that use of all available realizations is unneeded for the study system, so long as the ensemble design is well balanced. After accounting for the factors controlling <span class="hlt">streamflow</span> variance, results show that predicted average monthly change in <span class="hlt">streamflow</span> tends to follow precipitation changes and result in a net increase in the average annual precipitation and</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li class="active"><span>16</span></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_16 --> <div id="page_17" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li class="active"><span>17</span></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="321"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005AGUFM.C21A1074E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005AGUFM.C21A1074E"><span>Influence of Aspect on <span class="hlt">Snowmelt</span> Irradiation on Forested Mountain Slopes</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ellis, C. R.; Pomeroy, J. W.</p> <p>2005-12-01</p> <p>It is well known that <span class="hlt">snowmelt</span> energy from radiation varies due to the effects of topography and vegetation cover. However it is not well understood how the combination of topography and vegetation influences sub-canopy radiation fluxes to snow. To investigate, three natural lodgepole pine (Pinus contorta) stands in the Rocky Mountains of Marmot Creek Research Basin, Alberta, Canada were instrumented with radiometers. Radiation was observed at an open reference and beneath forests on north (20° slope; 351° azimuth) and southeast (19° slope; 126° azimuth) aspects with a level site serving as a control. Due to the presence of canopy gaps on the southeast slope, radiometers were placed in open, medium and dense parts of the stand. The pine forest exhibited variations in cover having mean tree densities of 1.83, 2.05 and 2.52 trees m-2 at southeast, level and north slopes. Both short-wave and long-wave incoming radiation fluxes were measured in sites with complete snow cover and experiencing melt. Ratios of sub-canopy short-wave irradiance to open-level site mean irradiance of 12.81 MJ m-2 d-1 were 0.38, 0.21 and 0.08 for southeast slope, level, and north slope forest sites, respectively. Sub-canopy long-wave irradiance ratios relative to the average open-level site irradiance of 9.61 MJ m-2 d-1 were 2.82, 2.82 and 2.87 respectively for southeast slope, level and north slope forest sites. Sub-canopy net radiation ratios relative to a mean net radiation of 3.2 MJ m-2 d-1 at the open-level site were 0.33, 0.09 and 0.07 for southeast, level and north slope forest sites. Lower north slope receipts of sub-canopy short-wave were found to be offset by an increased sub-canopy long-wave flux.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70186236','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70186236"><span>Terrestrial–aquatic linkages in spring-fed and <span class="hlt">snowmelt</span>-dominated streams</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Sepulveda, Adam</p> <p>2017-01-01</p> <p>The importance of trophic linkages between aquatic and terrestrial ecosystems is predicted to vary as a function of subsidy quantity and quality relative to in situ resources. To test this prediction, I used multi-year diet data from Bonneville cutthroat trout Oncorhynchus clarki Utah in spring-fed and <span class="hlt">snowmelt</span>-driven streams in the high desert of western North America. I documented that trout in spring-fed streams consumed more (number and weight) aquatic than terrestrial invertebrates, while trout in <span class="hlt">snowmelt</span>-driven streams consumed a similar number of both prey types but consumed more terrestrial than aquatic invertebrates by weight. Trout in spring-fed streams consumed more aquatic invertebrates than trout in <span class="hlt">snowmelt</span> streams and trout consumed more terrestrial invertebrates in <span class="hlt">snowmelt</span> than in spring-fed streams. Up to 93% of trout production in spring-fed streams and 60% in <span class="hlt">snowmelt</span> streams was fueled by aquatic invertebrates, while the remainder of trout production in each stream type was from terrestrial production. I found that the biomass and occurrence of consumed terrestrial invertebrates were not related to our measures of in situ resource quality or quantity in either stream type. These empirical data highlight the importance of autotrophic-derived production to trout in xeric regions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008AGUFM.C21C0572K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008AGUFM.C21C0572K"><span><span class="hlt">Snowmelt</span> infiltration and evapotranspiration in Red Fir forest ecosystems of the Sierra Nevada</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kirchner, P. B.; Bales, R. C.; North, M. P.; Small, E. E.</p> <p>2008-12-01</p> <p>Measurements from two forested catchments in the mixed conifer, Red Fir zone of the southern Sierra Nevada (2,200-2,600 m elevation) demonstrate the controls that topography and canopy cover exert over snow cover. Snow-depth, soil-moisture, stream-stage and sap-flow measurements from the Wolverton basin in Sequoia National Park and Teakettle Experimental Area in the Sierra National Forest exhibit distinct and rapid responses to spring <span class="hlt">snowmelt</span>. Spatial heterogeneity in snow water equivalent is influenced by tree clusters and individual canopies. <span class="hlt">Snowmelt</span> and soil moisture timing are controlled by proximity to stem of tree and canopy clustering. Aspect and slope position affect soil moisture, with drier conditions predominating on the steeper slopes. Synchronous fluctuations in soil moisture, stream flow and sap flow were observed. Continuous instrumental and synoptic survey data show snow water equivalent is approximately 15% less 1 m from the tree stem than in open areas at peak accumulation, with <span class="hlt">snowmelt</span> occurring in shaded open areas 1 to 4 weeks later than under canopy. Soil moisture tracks the <span class="hlt">snowmelt</span> pattern closely, with diel fluctuations in soil moisture under saturated conditions followed by an exponential dry-down to field capacity after <span class="hlt">snowmelt</span>. This is followed by a prolonged summer drought punctuated by rain events of <5% of total precipitation. Synoptic surveys of steeper slopes and multiple aspects show consistent patterns of drier conditions on steeper terrain.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4866651','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4866651"><span>Earlier <span class="hlt">snowmelt</span> and warming lead to earlier but not necessarily more plant growth</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Livensperger, Carolyn; Steltzer, Heidi; Darrouzet-Nardi, Anthony; Sullivan, Patrick F.; Wallenstein, Matthew; Weintraub, Michael N.</p> <p>2016-01-01</p> <p>Climate change over the past ∼50 years has resulted in earlier occurrence of plant life-cycle events for many species. Across temperate, boreal and polar latitudes, earlier seasonal warming is considered the key mechanism leading to earlier leaf expansion and growth. Yet, in seasonally snow-covered ecosystems, the timing of spring plant growth may also be cued by <span class="hlt">snowmelt</span>, which may occur earlier in a warmer climate. Multiple environmental cues protect plants from growing too early, but to understand how climate change will alter the timing and magnitude of plant growth, experiments need to independently manipulate temperature and <span class="hlt">snowmelt</span>. Here, we demonstrate that altered seasonality through experimental warming and earlier <span class="hlt">snowmelt</span> led to earlier plant growth, but the aboveground production response varied among plant functional groups. Earlier <span class="hlt">snowmelt</span> without warming led to early leaf emergence, but often slowed the rate of leaf expansion and had limited effects on aboveground production. Experimental warming alone had small and inconsistent effects on aboveground phenology, while the effect of the combined treatment resembled that of early <span class="hlt">snowmelt</span> alone. Experimental warming led to greater aboveground production among the graminoids, limited changes among deciduous shrubs and decreased production in one of the dominant evergreen shrubs. As a result, we predict that early onset of the growing season may favour early growing plant species, even those that do not shift the timing of leaf expansion. PMID:27075181</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28965255','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28965255"><span><span class="hlt">Snowmelt</span> timing, phenology, and growing season length in conifer forests of Crater Lake National Park, USA.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>O'Leary, Donal S; Kellermann, Jherime L; Wayne, Chris</p> <p>2017-09-30</p> <p>Anthropogenic climate change is having significant impacts on montane and high-elevation areas globally. Warmer winter temperatures are driving reduced snowpack in the western USA with broad potential impacts on ecosystem dynamics of particular concern for protected areas. Vegetation phenology is a sensitive indicator of ecological response to climate change and is associated with <span class="hlt">snowmelt</span> timing. Human monitoring of climate impacts can be resource prohibitive for land management agencies, whereas remotely sensed phenology observations are freely available at a range of spatiotemporal scales. Little work has been done in regions dominated by evergreen conifer cover, which represents many mountain regions at temperate latitudes. We used moderate resolution imaging spectroradiometer (MODIS) data to assess the influence of <span class="hlt">snowmelt</span> timing and elevation on five phenology metrics (green up, maximum greenness, senescence, dormancy, and growing season length) within Crater Lake National Park, Oregon, USA from 2001 to 2012. Earlier annual mean <span class="hlt">snowmelt</span> timing was significantly correlated with earlier onset of green up at the landscape scale. <span class="hlt">Snowmelt</span> timing and elevation have significant explanatory power for phenology, though with high variability. Elevation has a moderate control on early season indicators such as <span class="hlt">snowmelt</span> timing and green up and less on late-season variables such as senescence and growing season length. PCA results show that early season indicators and late season indicators vary independently. These results have important implications for ecosystem dynamics, management, and conservation, particularly of species such as whitebark pine (Pinus albicaulis) in alpine and subalpine areas.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/20672622','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/20672622"><span>[Spectral characters analysis of ground objects in <span class="hlt">snowmelt</span> period in the northern slope of Tianshan Mountains].</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Fang, Shi-Feng; Pei, Huan; Liu, Zhi-Hui</p> <p>2010-05-01</p> <p>Urumqi River Basin and Juntanghu Basin, located in the northern slope of Tianshan Mountains in Xinjiang, were selected as typical study areas. With the portable field spectrometer CI700 produced by CID in the United States and from a large number of field investigations and field measurements in the <span class="hlt">snowmelt</span> period (usually starts in the end of February or the beginning of March, and goes on for many days) from 2006 to 2009, a variety of spectral curves and their variation of typical ground objects in the <span class="hlt">snowmelt</span> period in the northern slope of Tianshan Mountains, such as snow, ice, water and soil, were obtained, and spectral characters analysis was carried out based on the collected data. The results showed that the classes of ground objects in <span class="hlt">snowmelt</span> period are quite monotone, however, a great challenge was brought about to the quantitative remote sensing research on surface parameters in <span class="hlt">snowmelt</span> period because of the interactive effects of the complex systems of snow-ice-water-soil, the spectral properties of typical ground objects, and their complex changes. Reflectance of soil with different moisture conditions is distinct, as well as reflectance of ice and snow under different environment or dissimilar mixtures have obvious development trends. The series of observations and analysis of the typical and complex spectral features in <span class="hlt">snowmelt</span> period are of great significance for the fundamental study of objects' spectral characteristics, as well as for the application of quantitative remote sensing studies.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://sfbay.wr.usgs.gov/publications/pdf/dettinger_1999_streamflow.pdf','USGSPUBS'); return false;" href="http://sfbay.wr.usgs.gov/publications/pdf/dettinger_1999_streamflow.pdf"><span>Global to local scale simulations of <span class="hlt">streamflow</span> in the Merced, American, and Carson Rivers, Sierra Nevada, California</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Dettinger, M.D.; Cayan, D.R.; Mo, K.; Jeton, A.E.</p> <p>1999-01-01</p> <p>Atmospheric moisture transport and moisture budgets during winter (December-April) simulated by the National Centers for Environmental Prediction (NCEP) regional spectral model (RSM) are examined and used to simulate <span class="hlt">streamflow</span> variations in the Sierra Nevada. The RSM was nested in 2"-latitude x 2"-longitude NCEPreanalyzed atmospheric-data fields (as a surrogate for a perfect forecast system operating at the global scale). Precipitation, temperature, and solar insolation simulated by the RSM on a 50-km grid were inputted directly to precipitation-runoff models of the Merced, American, and Carson Rivers in an evaluation of the potential for end-to-end forecasting of <span class="hlt">streamflow</span> and <span class="hlt">snowmelt</span> runoff from the Sierra Nevada, near 39"N 120"W. Over the western United States, the RSM captures both patterns and magnitudes of precipitation (e.g., Fig. I illustrates observed and simulated precipitation for winter 1982-83). The RSM has dry biases in the Southeast and over the Gulf of Mexico, but it captures interannual and intraseasonal variations well. During most El Nifios, it simulates a precipitation dipole over the western states with wetter-than-normal conditions in California and drier-than-normal in the Pacific Northwest. The Northeast is relatively dry and the southern states are wet, as in observations. The RSM did equally well during La Niiia winters.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.usgs.gov/of/2003/ofr03-148/','USGSPUBS'); return false;" href="https://pubs.usgs.gov/of/2003/ofr03-148/"><span>Questa baseline and pre-mining ground-water quality investigation. 2. Low-flow (2001) and <span class="hlt">snowmelt</span> (2002) synoptic/tracer water chemistry for the Red River, New Mexico</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>McCleskey, R. Blaine; Nordstrom, D. Kirk; Steiger, Judy I.; Kimball, Briant A.; Verplanck, Philip L.</p> <p>2003-01-01</p> <p>Water analyses are reported for 259 samples collected from the Red River, New Mexico, and its tributaries during low-flow(2001) and spring <span class="hlt">snowmelt</span> (2002) tracer studies. Water samples were collected along a 20-kilometer reach of the Red River beginning just east of the town of Red River and ending at the U.S. Geological Survey <span class="hlt">streamflow</span>-gaging station located east of Questa, New Mexico. The study area was divided into three sections where separate injections and synoptic sampling events were performed during the low-flow tracer study. During the spring <span class="hlt">snowmelt</span> tracer study, three tracer injections and synoptic sampling events were performed bracketing the areas with the greatest metal loading into the Red River as determined from the low-flow tracer study. The lowflow tracer synoptic sampling events were August 17, 20, and 24, 2001. The synoptic sampling events for the spring <span class="hlt">snowmelt</span> tracer were March 30, 31, and April 1, 2002. Stream and large inflow water samples were sampled using equal-width and depth-integrated sampling methods and composited into half-gallon bottles. Grab water samples were collected from smaller inflows. Stream temperatures were measured at the time of sample collection. Samples were transported to a nearby central processing location where pH and specific conductance were measured and the samples processed for chemical analyses. Cations, trace metals, iron redox species, and fluoride were analyzed at the U.S. Geological Survey laboratory in Boulder, Colorado. Cations and trace metal concentrations were determined using inductively coupled plasma-optical emission spectrometry and graphite furnace atomic absorption spectrometry. Arsenic concentrations were determined using hydride generation atomic absorption spectrometry, iron redox species were measured using ultraviolet-visible spectrometry, and fluoride concentrations were determined using an ion-selective electrode. Alkalinity was measured by automated titration, and sulfate</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://files.eric.ed.gov/fulltext/EJ131434.pdf','ERIC'); return false;" href="http://files.eric.ed.gov/fulltext/EJ131434.pdf"><span>The Safe Drinking Water Act First <span class="hlt">180</span> <span class="hlt">Days</span></span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Lehr, Jay H.</p> <p>1975-01-01</p> <p>The Safe Drinking Water Act protects our drinking and ground water resources. The Water Advisory Council interprets and implements the law. Implementation principles include high priorities for public health, cost considerations, state and local participation, environmental impact, decentralized decision making, and use of federal and state…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.usgs.gov/of/1982/0329/report.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/of/1982/0329/report.pdf"><span>Acoustic systems for the measurement of <span class="hlt">streamflow</span></span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Laenen, Antonius; Smith, Winchell</p> <p>1982-01-01</p> <p>Very little information is available concerning acoustic velocity meter (AVM) operation, performance, and limitations. This report provides a better understanding about the application of AVM instrumentation to <span class="hlt">streamflow</span> measurment. Operational U.S. Geological Survey systems have proven that AVM equipment is accurate and dependable. AVM equipment has no practical upper limit of measureable velocity if sonic transducers are securely placed and adequately protected, and will measure velocitites as low as 0.1 meter per second which is normally less than the threshold level for mechanical or head-loss meters. In some situations the performance of AVM equipment may be degraded by multipath interference, signal bending, signal attenuation, and variable streamline orientation. Smaller, less-expensive, more conveniently operable microprocessor equipment is now available which should increase use of AVM systems in <span class="hlt">streamflow</span> applications. (USGS)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70021978','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70021978"><span><span class="hlt">Streamflow</span> trends in the United States</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Lins, H.F.; Slack, J.R.</p> <p>1999-01-01</p> <p>Secular trends in <span class="hlt">streamflow</span> are evaluated for 395 climate-sensitive streamgaging stations in the conterminous United States using the non-parametric Mann-Kendall test. Trends are calculated for selected quantiles of discharge, from the 0th to the 100th percentile, to evaluate differences between low-, medium-, and high-flow regimes during the twentieth century. Two general patterns emerge; trends are most prevalent in the annual minimum (Q0) to median (Q50) flow categories and least prevalent in the annual maximum (Q100) category; and, at all but the highest quantiles, <span class="hlt">streamflow</span> has increased across broad sections of the United States. Decreases appear only in parts of the Pacific Northwest and the Southeast. Systematic patterns are less apparent in the Q100 flow. Hydrologically, these results indicate that the conterminous U.S. is getting wetter, but less extreme.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010EGUGA..1212312R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010EGUGA..1212312R"><span>Short-term ensemble <span class="hlt">streamflow</span> forecasting using operationally-produced single-valued <span class="hlt">streamflow</span> forecasts</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Regonda, Satish; Seo, Dong-Jun; Lawrence, Bill</p> <p>2010-05-01</p> <p>We present a statistical procedure that generates short-term <span class="hlt">streamflow</span> ensemble forecasts from single-valued, or deterministic, forecasts operationally produced by the National Weather Service (NWS) River Forecast Centers (RFC). The resulting ensemble forecast provides an estimate of the uncertainty in the single-valued forecast to aid risk-based decision making by the emergency managers and by the users of the forecast products and services. The single-valued forecasts are produced at a 6-hr time step for 5 days into the future, and reflect single-valued short-term quantitative precipitation and temperature forecasts (QPF, QTF) and various run-time modifications (MOD), or manual data assimilation, by human forecasters to reduce various sources of error in the end-to-end forecast process. The proposed procedure generates 5 day-ahead ensemble traces of <span class="hlt">streamflow</span> from a very parsimonious approximation of the conditional multivariate probability distribution of future <span class="hlt">streamflow</span> given the single-valued <span class="hlt">streamflow</span> forecasts, QPF and recent <span class="hlt">streamflow</span> observations. For parameter estimation and evaluation, we used a 10-year archive of the single-valued river stage forecasts for six forecast points in Oklahoma produced operationally by the Arkansas-Red River Basin River Forecast Center (ABRFC). To evaluate the procedure, we carried out dependent and leave-one-year-out cross validation. The resulting ensemble hindcasts are then verified using the Ensemble Verification System (EVS) developed at the NWS Office of Hydrologic Development (OHD).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5228185','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5228185"><span>Modulation of snow reflectance and <span class="hlt">snowmelt</span> from Central Asian glaciers by anthropogenic black carbon</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Schmale, Julia; Flanner, Mark; Kang, Shichang; Sprenger, Michael; Zhang, Qianggong; Guo, Junming; Li, Yang; Schwikowski, Margit; Farinotti, Daniel</p> <p>2017-01-01</p> <p>Deposited mineral dust and black carbon are known to reduce the albedo of snow and enhance melt. Here we estimate the contribution of anthropogenic black carbon (BC) to <span class="hlt">snowmelt</span> in glacier accumulation zones of Central Asia based on in-situ measurements and modelling. Source apportionment suggests that more than 94% of the BC is emitted from mostly regional anthropogenic sources while the remaining contribution comes from natural biomass burning. Even though the annual deposition flux of mineral dust can be up to 20 times higher than that of BC, we find that anthropogenic BC causes the majority (60% on average) of snow darkening. This leads to summer <span class="hlt">snowmelt</span> rate increases of up to 6.3% (7 cm a−1) on glaciers in three different mountain environments in Kyrgyzstan, based on albedo reduction and <span class="hlt">snowmelt</span> models. PMID:28079148</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017NatSR...740501S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017NatSR...740501S"><span>Modulation of snow reflectance and <span class="hlt">snowmelt</span> from Central Asian glaciers by anthropogenic black carbon</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Schmale, Julia; Flanner, Mark; Kang, Shichang; Sprenger, Michael; Zhang, Qianggong; Guo, Junming; Li, Yang; Schwikowski, Margit; Farinotti, Daniel</p> <p>2017-01-01</p> <p>Deposited mineral dust and black carbon are known to reduce the albedo of snow and enhance melt. Here we estimate the contribution of anthropogenic black carbon (BC) to <span class="hlt">snowmelt</span> in glacier accumulation zones of Central Asia based on in-situ measurements and modelling. Source apportionment suggests that more than 94% of the BC is emitted from mostly regional anthropogenic sources while the remaining contribution comes from natural biomass burning. Even though the annual deposition flux of mineral dust can be up to 20 times higher than that of BC, we find that anthropogenic BC causes the majority (60% on average) of snow darkening. This leads to summer <span class="hlt">snowmelt</span> rate increases of up to 6.3% (7 cm a‑1) on glaciers in three different mountain environments in Kyrgyzstan, based on albedo reduction and <span class="hlt">snowmelt</span> models.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFMNH53E..01W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFMNH53E..01W"><span>The HEPEX Seasonal <span class="hlt">Streamflow</span> Forecast Intercomparison Project</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wood, A. W.; Schepen, A.; Bennett, J.; Mendoza, P. A.; Ramos, M. H.; Wetterhall, F.; Pechlivanidis, I.</p> <p>2016-12-01</p> <p>The Hydrologic Ensemble Prediction Experiment (HEPEX; www.hepex.org) has launched an international seasonal <span class="hlt">streamflow</span> forecasting intercomparison project (SSFIP) with the goal of broadening community knowledge about the strengths and weaknesses of various operational approaches being developed around the world. While some of these approaches have existed for decades (e.g. Ensemble <span class="hlt">Streamflow</span> Prediction - ESP - in the United States and elsewhere), recent years have seen the proliferation of new operational and experimental <span class="hlt">streamflow</span> forecasting approaches. These have largely been developed independently in each country, thus it is difficult to assess whether the approaches employed in some centers offer more promise for development than others. This motivates us to establish a forecasting testbed to facilitate a diagnostic evaluation of a range of different <span class="hlt">streamflow</span> forecasting approaches and their components over a common set of catchments, using a common set of validation methods. Rather than prescribing a set of scientific questions from the outset, we are letting the hindcast results and notable differences in methodologies on a watershed-specific basis motivate more targeted analyses and sub-experiments that may provide useful insights. The initial pilot of the testbed involved two approaches - CSIRO's Bayesian joint probability (BJP) and NCAR's sequential regression - for two catchments, each designated by one of the teams (the Murray River, Australia, and Hungry Horse reservoir drainage area, USA). Additional catchments/approaches are in the process of being added to the testbed. To support this CSIRO and NCAR have developed data and analysis tools, data standards and protocols to formalize the experiment. These include requirements for cross-validation, verification, reference climatologies, and common predictands. This presentation describes the SSFIP experiments, pilot basin results and scientific findings to date.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70189268','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70189268"><span>Understanding uncertainties in future Colorado River <span class="hlt">streamflow</span></span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Julie A. Vano,; Bradley Udall,; Cayan, Daniel; Jonathan T Overpeck,; Brekke, Levi D.; Das, Tapash; Hartmann, Holly C.; Hidalgo, Hugo G.; Hoerling, Martin P; McCabe, Gregory J.; Morino, Kiyomi; Webb, Robert S.; Werner, Kevin; Lettenmaier, Dennis P.</p> <p>2014-01-01</p> <p>The Colorado River is the primary water source for more than 30 million people in the United States and Mexico. Recent studies that project streamf low changes in the Colorado River all project annual declines, but the magnitude of the projected decreases range from less than 10% to 45% by the mid-twenty-first century. To understand these differences, we address the questions the management community has raised: Why is there such a wide range of projections of impacts of future climate change on Colorado River <span class="hlt">streamflow</span>, and how should this uncertainty be interpreted? We identify four major sources of disparities among studies that arise from both methodological and model differences. In order of importance, these are differences in 1) the global climate models (GCMs) and emission scenarios used; 2) the ability of land surface and atmospheric models to simulate properly the high-elevation runoff source areas; 3) the sensitivities of land surface hydrology models to precipitation and temperature changes; and 4) the methods used to statistically downscale GCM scenarios. In accounting for these differences, there is substantial evidence across studies that future Colorado River <span class="hlt">streamflow</span> will be reduced under the current trajectories of anthropogenic greenhouse gas emissions because of a combination of strong temperature-induced runoff curtailment and reduced annual precipitation. Reconstructions of preinstrumental <span class="hlt">streamflows</span> provide additional insights; the greatest risk to Colorado River streamf lows is a multidecadal drought, like that observed in paleoreconstructions, exacerbated by a steady reduction in flows due to climate change. This could result in decades of sustained <span class="hlt">streamflows</span> much lower than have been observed in the ~100 years of instrumental record.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.usgs.gov/wsp/2213/report.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/wsp/2213/report.pdf"><span>Acoustic systems for the measurement of <span class="hlt">streamflow</span></span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Laenen, Antonius; Smith, Winchell</p> <p>1983-01-01</p> <p>The acoustic velocity meter (AVM), also referred to as an ultrasonic flowmeter, has been an operational tool for the measurement of <span class="hlt">streamflow</span> since 1965. Very little information is available concerning AVM operation, performance, and limitations. The purpose of this report is to consolidate information in such a manner as to provide a better understanding about the application of this instrumentation to <span class="hlt">streamflow</span> measurement. AVM instrumentation is highly accurate and nonmechanical. Most commercial AVM systems that measure <span class="hlt">streamflow</span> use the time-of-travel method to determine a velocity between two points. The systems operate on the principle that point-to-point upstream travel-time of sound is longer than the downstream travel-time, and this difference can be monitored and measured accurately by electronics. AVM equipment has no practical upper limit of measurable velocity if sonic transducers are securely placed and adequately protected. AVM systems used in <span class="hlt">streamflow</span> measurement generally operate with a resolution of ?0.01 meter per second but this is dependent on system frequency, path length, and signal attenuation. In some applications the performance of AVM equipment may be degraded by multipath interference, signal bending, signal attenuation, and variable streamline orientation. Presently used minicomputer systems, although expensive to purchase and maintain, perform well. Increased use of AVM systems probably will be realized as smaller, less expensive, and more conveniently operable microprocessor-based systems become readily available. Available AVM equipment should be capable of flow measurement in a wide variety of situations heretofore untried. New signal-detection techniques and communication linkages can provide additional flexibility to the systems so that operation is possible in more river and estuary situations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFMGC13E1239C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFMGC13E1239C"><span>Climate Change and the <span class="hlt">Snowmelt</span>-runoff Relationship in the Upper Rio Grande Basin</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chavarria, S. B.; Gutzler, D. S.</p> <p>2016-12-01</p> <p>Drought and rising temperatures have resulted in reduced snowpack and low flows in recent years for the Rio Grande, a vital source of surface water in three southwestern states and northern Mexico. We assess monthly and seasonal changes in <span class="hlt">streamflow</span> volume on the upper Rio Grande (URG) near its headwaters in southern Colorado for water years 1958-2015. We use gage data from the U.S. Geological Survey, naturalized <span class="hlt">streamflows</span> from the U.S. Natural Resources Conservation Service, and observed temperature, precipitation and snowpack data in the URG. Trends in discharge and downstream gains/losses are examined together with covariations in snow water equivalent, and surface climate variables. We test the hypothesis that climate change is already affecting the <span class="hlt">streamflow</span> volume derived from snow accumulation in ways consistent with CMIP-based model projections of 21st Century <span class="hlt">streamflow</span>, and we attempt to separate climate-related <span class="hlt">streamflow</span> signals from variability due to reservoir releases or diversions. Preliminary results indicate that decreasing snowpack and resulting diminution of springtime <span class="hlt">streamflow</span> in the URG are detectable in both observed and naturalized flow data beginning in the mid to late 1980s, despite the absence of significant decrease in total flow. Correlations between warm and cold season fluctuations in <span class="hlt">streamflow</span> and temperature or precipitation are being evaluated and will be compared to model projections. Our study will provide information that may be useful for validating hydroclimatic models and improving seasonal water supply outlooks, essential tools for water management.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.H13C1525E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.H13C1525E"><span>Modeling Change in Watershed <span class="hlt">Streamflow</span>, Groundwater Recharge and Surface Water - Groundwater Interactions Due to Irrigation and Associated Diversions and Pumping</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Essaid, H.; Caldwell, R. R.</p> <p>2015-12-01</p> <p>The impacts of irrigation and associated surface water (SW) diversions and groundwater (GW) pumping on instream flows, groundwater recharge and SW-GW interactions are being examined using a watershed-scale coupled SW-GW flow model. The U.S. Geological Survey (USGS) model GSFLOW (Markstrom et al., 2008), an integration of the USGS Precipitation-Runoff Modeling System (PRMS) and the Modular Ground-Water Flow Model (MODFLOW), is being utilized for this effort. Processes represented in this model include daily rain, snowfall, <span class="hlt">snowmelt</span>, <span class="hlt">streamflow</span>, surface runoff, interflow, infiltration, soil-zone evapotranspiration, and subsurface unsaturated and groundwater flow and evapotranspiration. The Upper Smith River watershed, an important agricultural and recreational area in west-central Montana, is being used as the basis for watershed climate, topography, hydrography, vegetation, soil properties as well as scenarios of irrigation and associated practices. The 640 square kilometer watershed area has been discretized into coincident 200 m by 200 m hydrologic response units (for climate and soil zone flow processes) and grid blocks (for unsaturated zone and GW flow processes). The subsurface GW system is discretized into 6 layers representing Quaternary alluvium, Tertiary sediments and bedrock. The model is being used to recreate natural, pre-development <span class="hlt">streamflows</span> and GW conditions in the watershed. The results of this simulation are then compared to a simulation with flood and sprinkler irrigation supplied by SW diversion and GW pumping to examine the magnitude and timing of changes in <span class="hlt">streamflow</span>, groundwater recharge and SW-GW interactions. Model results reproduce observed hydrologic responses to both natural climate variability and irrigation practices. Periodic irrigation creates increased evapotranspiration and GW recharge in cultivated areas of the watershed as well as SW-GW interactions that are more dynamic than under natural conditions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013HESSD..10.8503M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013HESSD..10.8503M"><span>Impacts of climate and forest changes on <span class="hlt">streamflow</span> and water balance in a mountainous headwater stream in Southern Alberta</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mahat, V.; Anderson, A.</p> <p>2013-07-01</p> <p>Rivers in Southern Alberta are vulnerable to climate change because much of the river water originates as snow in the eastern slopes of the Rocky Mountains. Changes in likelihood of forest disturbance (wildfire, insects, logging, etc.) may also have impacts that are compounded by climate change. This study evaluates the impacts of climate and forest changes on <span class="hlt">streamflow</span> in the upper parts of the Oldman River in Southern Alberta using a conceptual hydrological model, HBV-EC in combination with a stochastic weather generator (LARS-WG) driven by GCM (Global Climate Model) output climate data. Three climate change scenarios (A1B, A2 and B1) are selected to cover the range of possible future climate conditions (2020s, 2050s, and 2080s). GCM projected less than a 10% increase in precipitation in winter and a similar amount of precipitation decrease in summer. These changes in projected precipitation resulted in up to a 200% (9.3 mm) increase in winter <span class="hlt">streamflow</span> in February and up to a 63% (31.2 mm) decrease in summer flow in June. This amplification is mostly driven by the projected increase in temperature that is predicted to melt winter snow earlier, possibly resulting in lower water availability in the <span class="hlt">snowmelt</span> dominated regions during the summer. Uncertainty analysis was completed using a guided GLUE (generalized likelihood uncertainty estimation) approach to obtain the best 100 parameter sets and associated ranges of <span class="hlt">streamflows</span>. The impacts of uncertainty were higher in spring and summer flows than in winter and fall flows. Forest change compounded the climate change impact by increasing winter flow; however, it did not reduce the summer flow.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li class="active"><span>17</span></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_17 --> <div id="page_18" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li class="active"><span>18</span></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="341"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.H11F0925D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.H11F0925D"><span>Informing Water Management by Direct Use of Snow Information as Surrogate of Medium-to-Long Range <span class="hlt">Streamflow</span> Forecast</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Denaro, S.; Giuliani, M.; Castelletti, A.</p> <p>2014-12-01</p> <p>Medium-to-long range <span class="hlt">streamflow</span> forecast provide a key assistance in anticipating hydro- climatic adverse events and prompting effective adaptation measures. For instance, accurate medium-long range <span class="hlt">streamflow</span> forecasts have a great potential to improve water reservoir operation by enabling more efficient allocation of water volumes in time (e.g. via hedging). Unfortunately, these forecasts often lacks reliability and accuracy, especially when low-frequency climate forcing (e.g. ENSO) is not intense enough to improve the forecast lead time (e.g. in Europe), and might be computationally very demanding, In this work, we explore the direct use of both rough snow data (e.g. snow depth) and snow water equivalent estimates as surrogate of medium-to-long range <span class="hlt">streamflow</span> forecast to inform the operation of a regulated lake. The underlying idea is that snow data contains key information on current and future water availability throughout the snow melting season that might significantly improve the operation's anticipation potential. We adopt a three step methodology: First, we compute the upper bound of the system performance by assuming perfect foresight and we assess the value of additional information as the difference between this ideal solution and current operation. Using input variable selection, we then select the most relevant snow information to explain the release trajectory associated to the upper bound operating policy. Finally, we derive the optimal policy conditioned upon the selected variables by Multi-Objecting Evolutionary Direct Policy Search. The methodology is demonstrated on the snow-dominated Lake Como river basin, in the Italian Alps. Lake Como is a regulated lake primarily used to supply water to a large cultivated area and <span class="hlt">snowmelt</span> from May-July is the most important contribution to the creation of the seasonal storage. Results show that using raw data or simple SWE estimates can largely improve anticipation capability in the daily operation of</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70127899','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70127899"><span><span class="hlt">Streamflow</span> and sediment dynamics of the Middle Rio Grande Valley, New Mexico, in the context of cottonwood recruitment</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Milhous, Robert T.; Wondzell, Mark; Ritter, Amy</p> <p>1993-01-01</p> <p>The cottonwood gallery forests of the Middle Rio Grande floodplain in New Mexico provide important habitats for birds and other animals. Over the last century, these forests have changed significantly due to invasion of exotics such as salt cedar and Russian olive, which compete with native cottonwoods, and changes in water use both in the valley and upstream. To successfully germinate and establish, cottonwoods require an adequate water supply, abundant sunlight, and bare, litter-free substrate. Native cottonwoods are adapted to a natural <span class="hlt">snowmelt</span> hydrograph characterized by spring floods in late May or early June and gradually receding <span class="hlt">streamflows</span> throughout the remainder of the summer. The natural <span class="hlt">streamflow</span> pattern has been significantly modified by water management in the Rio Grande basin. The modified pattern is less conducive to establishment of cottonwoods than the natural pattern. In addition, exotic species now compete with native cottonwoods, and the modified flow pattern may favor these exotics. The overall objective of this study was to investigate the possibility of enhancing cottonwood establishment and recruitment along the Middle Rio Grande through <span class="hlt">streamflow</span> manipulation and reservoir releases. The work integrates concepts of cottonwood establishment, water resources management, and river morphology, and investigates how water management might be used to preserve and enhance cottonwood gallery forests along the river. Specific objectives of the work reported herein were to: (1) develop a technique to calculate flows that will produce channel characteristics necessary to restore and sustain cottonwood gallery forests; (2) develop a model to determine a flow pattern, or sequence of flows, that will improve the potential for cottonwood establishment and recruitment; and (3) determine if the water resources can be managed to produce the desired channel characteristics and flow pattern identified in (1) and (2).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004JGRD..109.7S91L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004JGRD..109.7S91L"><span><span class="hlt">Streamflow</span> and water balance intercomparisons of four land surface models in the North American Land Data Assimilation System project</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lohmann, Dag; Mitchell, Kenneth E.; Houser, Paul R.; Wood, Eric F.; Schaake, John C.; Robock, Alan; Cosgrove, Brian A.; Sheffield, Justin; Duan, Qingyun; Luo, Lifeng; Higgins, R. Wayne; Pinker, Rachel T.; Tarpley, J. Dan</p> <p>2004-04-01</p> <p>This paper is part of a series of papers about the multi-institutional North American Land Data Assimilation System (NLDAS) project. It compares and evaluates <span class="hlt">streamflow</span> and water balance results from four different land surface models (LSMs) within the continental United States. These LSMs have been run for the retrospective period from 1 October 1996 to 30 September 1999 forced by atmospheric observations from the Eta Data Assimilation System (EDAS) analysis, measured precipitation, and satellite-derived downward solar radiation. These model runs were performed on a common 1/8° latitude-longitude grid and used the same database for soil and vegetation classifications. We have evaluated these simulations using U.S. Geological Survey (USGS) measured daily <span class="hlt">streamflow</span> data for 9 large major basins and 1145 small- to medium-sized basins from 23 km2 to 10,000 km2 distributed over the NLDAS domain. Model runoff was routed with a common distributed and a lumped optimized linear routing model. The diagnosis of the model water balance results demonstrates strengths and weaknesses in the models, our insufficient knowledge of ad hoc parameters used for the model runs, the interdependence of model structure and model physics, and the lack of good forcing data in parts of the United States, especially in regions with extended snow cover. Overall, the differences between the LSM water balance terms are of the same magnitude as the mean water balance terms themselves. The modeled mean annual runoff shows large regional differences by a factor of up to 4 between models. The corresponding difference in mean annual evapotranspiration is about a factor of 2. The analysis of runoff timing for the LSMs demonstrates the importance of correct <span class="hlt">snowmelt</span> timing, where the resulting differences in <span class="hlt">streamflow</span> timing can be up to four months. Runoff is underestimated by all LSMs in areas with significant snowfall.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005JGRD..110.8112S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005JGRD..110.8112S"><span><span class="hlt">Streamflow</span> simulations of the terrestrial Arctic domain</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Su, Fengge; Adam, Jennifer C.; Bowling, Laura C.; Lettenmaier, Dennis P.</p> <p>2005-04-01</p> <p>Predicting riverine discharge to the Arctic Ocean has become increasingly important because of the dominant role that river runoff plays in the freshwater balance of the Arctic Ocean, and the predicted high sensitivity of the region to global warming. The ability of land surface models to represent runoff and <span class="hlt">streamflow</span> from northern river basins is critical to an understanding of the Arctic hydrologic cycle. A set of simulations with the land surface scheme VIC (Variable Infiltration Capacity) implemented at 100 km EASE-Grid across the pan-Arctic domain was conducted to evaluate the model's representation of various hydrologic processes in the Arctic land region, and to provide a consistent baseline hydroclimatology for the region. The pan-Arctic drainage basin system was partitioned into 12 regions for purposes of model implementation and testing. <span class="hlt">Streamflow</span> observations at various basin outlets, satellite-based snow cover extent, observed dates of lake freeze-up and break-up, and sited monitored summer permafrost maximum active layer thickness were used to evaluate various simulated hydrologic variables. The results indicate that the VIC model was able to reproduce these hydrologic processes in the Arctic region. A 21-year average river inflow (1979-1999) to the Arctic Ocean from the AORB (Arctic Ocean River Basin) illustrated in Prowse and Flegg (2000), was estimated with the simulated <span class="hlt">streamflow</span> as 3354 km3/yr, and 3596 km3/yr with the inclusion of the Arctic Archepelago, which are comparable to the previous estimates derived from the observed data.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.usgs.gov/fs/2008/3042/','USGSPUBS'); return false;" href="https://pubs.usgs.gov/fs/2008/3042/"><span><span class="hlt">Streamflow</span> of 2007--Water year summary</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Xiaodong, Jian; Wolock, David M.; Lins, Harry F.</p> <p>2008-01-01</p> <p>The maps and graphs appearing in this summary describe <span class="hlt">streamflow</span> conditions for water-year 2007 (October 1, 2006 to September 30, 2007) in the context of the 78-year period 1930-2007, unless otherwise noted. The illustrations are based on observed data from the U.S. Geological Survey's (USGS) National <span class="hlt">Streamflow</span> Information Program. The period 1930-2007 was used because prior to 1930, the number of streamgages was too small to provide representative data for computing statistics for most regions of the country. In the summary, reference is made to the term "runoff," which is the depth to which a river basin, State, or other geographic area would be covered with water if all the <span class="hlt">streamflow</span> within the area during a single year was uniformly distributed upon it. Runoff quantifies the magnitude of water flowing through the Nation's rivers and streams in measurement units that can be compared from one area to another. The runoff value for a geographic area is computed as the median runoff value for all streamgages in that geographic area. For example, the runoff value for a State is the median for all streamgages in that State, and the median for the Nation is the median value for all streamgages in the Nation. Each of the maps and graphs below can be expanded to a larger view by clicking on the image. In all the graphics, a rank of 1 indicates the highest flow of all years analyzed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.usgs.gov/fs/2009/3003/','USGSPUBS'); return false;" href="https://pubs.usgs.gov/fs/2009/3003/"><span><span class="hlt">Streamflow</span> of 2008--Water year summary</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Xiaodong, Jian; Wolock, David M.; Lins, Harry F.; Brady, Steve</p> <p>2009-01-01</p> <p>The maps and graphs appearing in this summary describe <span class="hlt">streamflow</span> conditions for water-year 2008 (October 1, 2007 to September 30, 2008) in the context of the 79-year period 1930-2008, unless otherwise noted. The illustrations are based on observed data from the U.S. Geological Survey's (USGS) National <span class="hlt">Streamflow</span> Information Program. The period 1930-2008 was used because prior to 1930, the number of streamgages was too small to provide representative data for computing statistics for most regions of the country. In the summary, reference is made to the term "runoff," which is the depth to which a river basin, State, or other geographic area would be covered with water if all the <span class="hlt">streamflow</span> within the area during a single year was uniformly distributed upon it. Runoff quantifies the magnitude of water flowing through the Nation's rivers and streams in measurement units that can be compared from one area to another. The runoff value for a geographic area is computed as the median runoff value for all streamgages in that geographic area. For example, the runoff value for a State is the median for all streamgages in that State, and the median for the Nation is the median value for all streamgages in the Nation. Each of the maps and graphs below can be expanded to a larger view by clicking on the image. In all the graphics, a rank of 1 indicates the highest flow of all years analyzed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.usgs.gov/fs/2010/3058/','USGSPUBS'); return false;" href="https://pubs.usgs.gov/fs/2010/3058/"><span><span class="hlt">Streamflow</span> of 2009--Water year summary</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Xiaodong, Jian; Wolock, David M.; Lins, Harry F.; Brady, Steve</p> <p>2010-01-01</p> <p>The maps and graph in this summary describe <span class="hlt">streamflow</span> conditions for water-year 2009 (October 1, 2008 to September 30, 2009) in the context of the 80-year period 1930-2009, unless otherwise noted. The illustrations are based on observed data from the U.S. Geological Survey's National <span class="hlt">Streamflow</span> Information Program. The period 1930-2009 was used because prior to 1930, the number of streamgages was too small to provide representative data for computing statistics for most regions of the country. In the summary, reference is made to the term "runoff," which is the depth to which a river basin, State, or other geographic area would be covered with water if all the <span class="hlt">streamflow</span> within the area during a single year was uniformly distributed upon it. Runoff quantifies the magnitude of water flowing through the Nation's rivers and streams in measurement units that can be compared from one area to another. Each of the maps and graphs can be expanded to a larger view by clicking on the image. In all the graphics, a rank of 1 indicates the highest flow of all years analyzed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.usgs.gov/fs/2007/3062/','USGSPUBS'); return false;" href="https://pubs.usgs.gov/fs/2007/3062/"><span><span class="hlt">Streamflow</span> of 2006 -- Water Year Summary</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Lins, Harry</p> <p>2007-01-01</p> <p>The maps and graphs appearing in this summary describe <span class="hlt">streamflow</span> conditions for water-year 2006 (October 1, 2005 to September 30, 2006) in the context of the 77-year period 1930-2006, unless otherwise noted. The illustrations are based on observed data from the U.S. Geological Survey's (USGS) National <span class="hlt">Streamflow</span> Information Program. The period 1930-2006 was used because prior to 1930, the number of streamgages was too small to provide representative data for computing statistics for most regions of the country. In the summary, reference is made to the term 'runoff,' which is the depth to which a river basin, State, or other geographic area would be covered with water if all the <span class="hlt">streamflow</span> within the area during a single year was uniformly distributed upon it. Runoff quantifies the magnitude of water flowing through the Nation's rivers and streams in measurement units that can be compared from one area to another. The runoff value for a geographic area is computed as the median runoff value for all streamgages in that geographic area. For example, the runoff value for a state is the median for all streamgages in that state, and the median for the Nation is the median value for all streamgages in the Nation. Each of the maps and graphs below can be expanded to a larger view by clicking on the image. In all the graphics, a rank of 1 indicates the highest flow of all years analyzed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.usgs.gov/fs/2013/3026/fs2013-3026.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/fs/2013/3026/fs2013-3026.pdf"><span><span class="hlt">Streamflow</span> of 2012--Water Year Summary</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Jian, Xiaodong; Wolock, David M.; Lins, Harry F.; Brady, Steve</p> <p>2013-01-01</p> <p>The maps and graphs in this summary describe <span class="hlt">streamflow</span> conditions for water year 2012 (October 1, 2011, to September 30, 2012) in the context of the 83-year period from 1930 through 2012, unless otherwise noted. The illustrations are based on observed data from the U.S. Geological Survey’s (USGS) National <span class="hlt">Streamflow</span> Information Program (http://water.usgs.gov/nsip/). The period 1930–2012 was used because, prior to 1930, the number of streamgages was too small to provide representative data for computing statistics for most regions of the country. In the summary, reference is made to the term “runoff,” which is the depth to which a river basin, State, or other geographic area would be covered with water if all the <span class="hlt">streamflow</span> within the area during a specified time period was uniformly distributed upon it. Runoff quantifies the magnitude of water flowing through the Nation’s rivers and streams in measurement units that can be compared from one area to another.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.usgs.gov/fs/2011/3043/','USGSPUBS'); return false;" href="https://pubs.usgs.gov/fs/2011/3043/"><span><span class="hlt">Streamflow</span> of 2010--Water year summary</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Xiaodong, Jian; Wolock, David M.; Lins, Harry F.; Brady, Steve</p> <p>2011-01-01</p> <p>The maps and graph in this summary describe <span class="hlt">streamflow</span> conditions for water-year 2010 (October 1, 2009 to September 30, 2010) in the context of the 81-year period 1930-2010, unless otherwise noted. The illustrations are based on observed data from the U.S. Geological Survey's (USGS) National <span class="hlt">Streamflow</span> Information Program. The period 1930-2010 was used because prior to 1930, the number of streamgages was too small to provide representative data for computing statistics for most regions of the country. In the summary, reference is made to the term "runoff," which is the depth to which a river basin, State, or other geographic area would be covered with water if all the <span class="hlt">streamflow</span> within the area during a single year was uniformly distributed upon it. Runoff quantifies the magnitude of water flowing through the Nation's rivers and streams in measurement units that can be compared from one area to another. Each of the maps and graphs below can be expanded to a larger view by clicking on the image. In all the graphics, a rank of 1 indicates the highest flow of all years analyzed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.usgs.gov/fs/2012/3085/fs2012-3085.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/fs/2012/3085/fs2012-3085.pdf"><span><span class="hlt">Streamflow</span> of 2011 - Water Year Summary</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Jian, Xiaodong; Wolock, David M.; Lins, Harry F.; Brady, Steve</p> <p>2012-01-01</p> <p>The maps and graph in this summary describe <span class="hlt">streamflow</span> conditions for water year 2011 (October 1, 2010, to September 30, 2011) in the context of the 82-year period from 1930 through 2011, unless otherwise noted. The illustrations are based on observed data from the U.S. Geological Survey's (USGS) National <span class="hlt">Streamflow</span> Information Program (http://water.usgs.gov/nsip/). The period 1930-2010 was used because, prior to 1930, the number of streamgages was too small to provide representative data for computing statistics for most regions of the country. In the summary, reference is made to the term "runoff," which is the depth to which a river basin, State, or other geographic area would be covered with water if all the <span class="hlt">streamflow</span> within the area during a single year was uniformly distributed upon it. Runoff quantifies the magnitude of water flowing through the Nation's rivers and streams in measurement units that can be compared from one area to another. Each of the maps and graphs can be expanded to a larger view by clicking on the image. In all of the graphics, a rank of 1 indicates the highest flow of all years analyzed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25602552','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25602552"><span>Comparison of Temperature-Index <span class="hlt">Snowmelt</span> Models for Use within an Operational Water Quality Model.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Watson, Brett M; Putz, Gordon</p> <p>2014-01-01</p> <p>The accurate prediction of <span class="hlt">snowmelt</span> runoff is a critical component of integrated hydrological and water quality models in regions where snowfall constitutes a significant portion of the annual precipitation. In cold regions, the accumulation of a snowpack and the subsequent spring <span class="hlt">snowmelt</span> generally constitutes a major proportion of the annual water yield. Furthermore, the <span class="hlt">snowmelt</span> runoff transports significant quantities of sediment and nutrients to receiving streams and strongly influences downstream water quality. Temperature-index models are commonly used in operational hydrological and water quality models to predict <span class="hlt">snowmelt</span> runoff. Due to their simplicity, computational efficiency, low data requirements, and ability to consistently achieve good results, numerous temperature-index models of varying complexity have been developed in the past few decades. The objective of this study was to determine how temperature-index models of varying complexity would affect the performance of the water quality model SWAT (a modified version of SWAT that was developed for watersheds dominated by boreal forest) for predicting runoff. Temperature-index models used by several operational hydrological models were incorporated into SWAT. Model performance was tested on five watersheds on the Canadian Boreal Plain whose hydrologic response is dominated by <span class="hlt">snowmelt</span> runoff. The results of this study indicate that simpler temperature-index models can perform as well as more complex temperature-index models for predicting runoff from the study watersheds. The outcome of this study has important implications because the incorporation of simpler temperature-index <span class="hlt">snowmelt</span> models into hydrological and water quality models can lead to a reduction in the number of parameters that need to be optimized without sacrificing predictive accuracy.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70023931','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70023931"><span>Processes regulating watershed chemical export during <span class="hlt">snowmelt</span>, fraser experimental forest, Colorado</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Stottlemyer, R.</p> <p>2001-01-01</p> <p>In the Central Rocky Mountains, snowfall dominates precipitation. Airborne contaminants retained in the snowpack can affect high elevation surface water chemistry during <span class="hlt">snowmelt</span>. At the Fraser Experimental Forest (FEF), located west of the Continental Divide in Central Colorado, <span class="hlt">snowmelt</span> dominates the annual hydrograph, and accounts for >95% of annual stream water discharge. During the winters of 1989-1993, we measured precipitation inputs, snowpack water equivalent (SWE) and ion content, and stream water chemistry every 7-10 days along a 3150-3500 m elevation gradient in the subalpine and alpine Lexen Creek watershed. The study objectives were to (1) quantify the distribution of SWE and snowpack chemical content with elevation and aspect, (2) quantify <span class="hlt">snowmelt</span> rates, temperature of soil, snowpack, and air with elevation and aspect, and (3) use change in upstream-downstream water chemistry during <span class="hlt">snowmelt</span> to better define alpine and subalpine flowpaths. The SWE increased with elevation (P - 3??C) temperatures throughout winter which resulted in significant snowpack ion loss. By snowpack PWE in mid May, the snowpack had lost almost half the cumulative precipitation H+, NH4+, and SO42- inputs and a third of the NO3- input. Windborne soil particulate inputs late in winter increased snowpack base cation content. Variation in subalpine SWE and snowpack ion content with elevation and aspect, and wind redistribution of snowfall in the alpine resulted in large year-to-year differences in the timing and magnitude of SWE, PWE, and snowpack ion content. The alpine stream water ion concentrations changed little during <span class="hlt">snowmelt</span> indicating meltwater passed quickly through surface porous soils and was well mixed before entering the stream. Conversely, subalpine stream water chemistry was diluted during <span class="hlt">snowmelt</span> suggesting much melt water moved to the stream as shallow subsurface lateral flow. Published by Elsevier Science B.V.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013HESSD..1015071Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013HESSD..1015071Y"><span>Modeling the snow surface temperature with a one-layer energy balance <span class="hlt">snowmelt</span> model</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>You, J.; Tarboton, D. G.; Luce, C. H.</p> <p>2013-12-01</p> <p>⪉bel{sec:abstract} Snow surface temperature is a key control on energy exchanges at the snow surface, particularly net longwave radiation and turbulent energy fluxes. The snow surface temperature is in turn controlled by the balance between various external fluxes and the conductive heat flux, internal to the snowpack. Because of the strong insulating properties of snow, thermal gradients in snow packs are large and nonlinear, a fact that has led many to advocate multiple layer <span class="hlt">snowmelt</span> models over single layer models. In an effort to keep <span class="hlt">snowmelt</span> modeling simple and parsimonious, the Utah Energy Balance (UEB) <span class="hlt">snowmelt</span> model used only one layer but allowed the snow surface temperature to be different from the snow average temperature by using an equilibrium gradient parameterization based on the surface energy balance. Although this procedure was considered an improvement over the ordinary single layer <span class="hlt">snowmelt</span> models, it still resulted in discrepancies between modeled and measured snowpack energy contents. In this paper we examine the parameterization of snow surface temperature in single layer <span class="hlt">snowmelt</span> models from the perspective of heat conduction into a semi-infinite medium. We evaluate the equilibrium gradient approach, the force-restore approach, and a modified force-restore approach. In addition, we evaluate a scheme for representing the penetration of a refreezing front in cold periods following melt. We also introduce a method to adjust effective conductivity to account for the presence of ground near to a shallow snow surface. These parameterizations were tested against data from the Central Sierra Snow Laboratory, CA, Utah State University experimental farm, UT, and Subnivean snow laboratory at Niwot Ridge, CO. These tests compare modeled and measured snow surface temperature, snow energy content, snow water equivalent, and <span class="hlt">snowmelt</span> outflow. We found that with these refinements the model is able to better represent the snowpack energy balance and</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013BGeo...10.7631L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013BGeo...10.7631L"><span>Comparison of inorganic nitrogen uptake dynamics following <span class="hlt">snowmelt</span> and at peak biomass in subalpine grasslands</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Legay, N.; Grassein, F.; Robson, T. M.; Personeni, E.; Bataillé, M.-P.; Lavorel, S.; Clément, J.-C.</p> <p>2013-11-01</p> <p>Subalpine grasslands are highly seasonal environments and likely subject to strong variability in nitrogen (N) dynamics. Plants and microbes typically compete for N acquisition during the growing season and particularly at plant peak biomass. During <span class="hlt">snowmelt</span>, plants could potentially benefit from a decrease in competition by microbes, leading to greater plant N uptake associated with active growth and freeze-thaw cycles restricting microbial growth. In managed subalpine grasslands, we expect these interactions to be influenced by recent changes in agricultural land use, and associated modifications in plant and microbial communities. At several subalpine grasslands in the French Alps, we added pulses of 15N to the soil at the end of <span class="hlt">snowmelt</span>, allowing us to compare the dynamics of inorganic N uptake in plants and microbes during this period with that previously reported at the peak biomass in July. In all grasslands, while specific shoot N translocation (per g of biomass) of dissolved inorganic nitrogen (DIN) was two to five times greater at <span class="hlt">snowmelt</span> than at peak biomass, specific microbial DIN uptakes were similar between the two sampling dates. On an area basis, plant communities took more DIN than microbial communities at the end of <span class="hlt">snowmelt</span> when aboveground plant biomasses were at least two times lower than at peak biomass. Consequently, inorganic N partitioning after <span class="hlt">snowmelt</span> switches in favor of plant communities, allowing them to support their growing capacities at this period of the year. Seasonal differences in microbial and plant inorganic N-related dynamics were also affected by past (terraced vs. unterraced) rather than current (mown vs. unmown) land use. In terraced grasslands, microbial biomass N remained similar across seasons, whereas in unterraced grasslands, microbial biomass N was higher and microbial C : N lower at the end of <span class="hlt">snowmelt</span> as compared to peak biomass. Further investigations on microbial community composition and their organic N</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013BGD....10.8887L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013BGD....10.8887L"><span>Comparison of inorganic nitrogen uptake dynamics following <span class="hlt">snowmelt</span> and at peak biomass in subalpine grasslands</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Legay, N.; Grassein, F.; Robson, T. M.; Personeni, E.; Bataillé, M.-P.; Lavorel, S.; Clément, J.-C.</p> <p>2013-05-01</p> <p>Subalpine grasslands are highly seasonal environments and likely subject to strong variability in nitrogen (N) dynamics. Plants and microbes typically compete for N acquisition during the growing season and particularly at plant peak biomass. During <span class="hlt">snowmelt</span>, plants could potentially benefit from a decrease in competition by microbes because of greater plant N uptake associated with active growth and freeze-thaw cycles restricting microbial growth. In managed subalpine grasslands, we expect these interactions to be influenced by recent changes in agricultural land-use, and associated modifications in plant and microbial communities. At a subalpine grassland site in the Central French Alps, a pulse of 15N was added to the soil at the end of <span class="hlt">snowmelt</span>, allowing us to compare the dynamics of inorganic N uptake in plants and microbes during this period with that previously reported at the peak biomass in July. In all grasslands, specific plant (per g of biomass) dissolved inorganic N (DIN) uptake was two to five times greater at <span class="hlt">snow-melt</span> than at peak biomass, whereas the specific microbial DIN uptakes were similar between the two sampling dates. On an area basis, plant communities took more DIN than microbial communities at the end of <span class="hlt">snowmelt</span>, and the intensity of this DIN uptake by plants differed across land use types. Consequently, N partitioning after <span class="hlt">snowmelt</span> switches in favor of plant communities allowing them to support their growing capacities at this period of the year. Seasonal differences in microbial and plant N-related dynamics were also affected by past (terraced vs. unterraced) rather than current (mown vs. unmown) land use. In terraced grasslands, microbial biomass N remained similar across seasons, whereas in unterraced grasslands, microbial biomass N was higher and microbial C : N lower at the end of <span class="hlt">snowmelt</span> as compared to peak biomass. Further investigations on microbial community composition and their organic N uptake dynamics are required to</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28851224','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28851224"><span>A Pulse of Mercury and Major Ions in <span class="hlt">Snowmelt</span> Runoff from a Small Arctic Alaska Watershed.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Douglas, Thomas A; Sturm, Matthew; Blum, Joel D; Polashenski, Christopher; Stuefer, Svetlana; Hiemstra, Christopher; Steffen, Alexandra; Filhol, Simon; Prevost, Romain</p> <p>2017-10-03</p> <p>Atmospheric mercury (Hg) is deposited to Polar Regions during springtime atmospheric mercury depletion events (AMDEs) that require halogens and snow or ice surfaces. The fate of this Hg during and following <span class="hlt">snowmelt</span> is largely unknown. We measured Hg, major ions, and stable water isotopes from the snowpack through the entire spring melt runoff period for two years. Our small (2.5 ha) watershed is near Barrow (now Utqiaġvik), Alaska. We measured discharge, made 10 000 snow depths, and collected over 100 samples of snow and meltwater for chemical analysis in 2008 and 2009 from the watershed snowpack and ephemeral stream channel. Results show an "ionic pulse" of mercury and major ions in runoff during both <span class="hlt">snowmelt</span> seasons, but major ion and Hg runoff concentrations were roughly 50% higher in 2008 than in 2009. Though total discharge as a percent of total watershed snowpack water equivalent prior to the melt was similar in both years (36% in 2008 melt runoff and 34% in 2009), it is possible that record low precipitation in the summer of 2007 led to the higher major ion and Hg concentrations in 2008 melt runoff. Total dissolved Hg meltwater runoff of 14.3 (± 0.7) mg/ha in 2008 and 8.1 (± 0.4) mg/ha in 2009 is five to seven times higher than that reported from other arctic watersheds. We calculate 78% of snowpack Hg was exported with <span class="hlt">snowmelt</span> runoff in 2008 and 41% in 2009. Our results suggest AMDE Hg complexed with Cl(-) or Br(-) may be less likely to be photochemically reduced and re-emitted to the atmosphere prior to <span class="hlt">snowmelt</span>, and we estimate that roughly 25% of the Hg in <span class="hlt">snowmelt</span> is attributable to AMDEs. Projected Arctic warming, with more open sea ice leads providing halogen sources that promote AMDEs, may provide enhanced Hg deposition, reduced Hg emission and, ultimately, an increase in snowpack and <span class="hlt">snowmelt</span> runoff Hg concentrations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013HESS...17.3577G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013HESS...17.3577G"><span>Using the nonlinear aquifer storage-discharge relationship to simulate the base flow of glacier- and <span class="hlt">snowmelt</span>-dominated basins in northwest China</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gan, R.; Luo, Y.</p> <p>2013-09-01</p> <p>Base flow is an important component in hydrological modeling. This process is usually modeled by using the linear aquifer storage-discharge relation approach, although the outflow from groundwater aquifers is nonlinear. To identify the accuracy of base flow estimates in rivers dominated by <span class="hlt">snowmelt</span> and/or glacier melt in arid and cold northwestern China, a nonlinear storage-discharge relationship for use in SWAT (Soil Water Assessment Tool) modeling was developed and applied to the Manas River basin in the Tian Shan Mountains. Linear reservoir models and a digital filter program were used for comparisons. Meanwhile, numerical analysis of recession curves from 78 river gauge stations revealed variation in the parameters of the nonlinear relationship. It was found that the nonlinear reservoir model can improve the <span class="hlt">streamflow</span> simulation, especially for low-flow period. The higher Nash-Sutcliffe efficiency, logarithmic efficiency, and volumetric efficiency, and lower percent bias were obtained when compared to the one-linear reservoir approach. The parameter b of the aquifer storage-discharge function varied mostly between 0.0 and 0.1, which is much smaller than the suggested value of 0.5. The coefficient a of the function is related to catchment properties, primarily the basin and glacier areas.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.usgs.gov/wri/1983/4263/report.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/wri/1983/4263/report.pdf"><span>Calibration procedure for a daily flow model of small watersheds with <span class="hlt">snowmelt</span> runoff in the Green River coal region of Colorado</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Norris, J.M.; Parker, R.S.</p> <p>1985-01-01</p> <p>A calibration procedure was developed for the U.S. Geological Survey 's Precipitation-Runoff Modeling System for watersheds in which <span class="hlt">snowmelt</span> is the major contributor to runoff. The model uses daily values of air temperature and precipitation as input and the output is mean daily discharge. The procedure appears sufficient to calibrate both <span class="hlt">streamflow</span> volume and the timing of mean daily discharge if other model parameters are reasonably estimated. Model structure and sensitivity analysis suggest that one of the most important parameters is the available water-holding capacity of the soil (SMAX). Changing this parameter through a series of iterations, the calibration procedure minimizes the error between observed and predicted annual discharge. The calibration suggests that the single parameter SMAX may be sufficient for optimizing both the volumes and the timing of runoff, assuming other model parameters are adequately estimated. Additional optimization on parameters sensitive to timing does not appear to improve prediction. This indicates that these parameters were estimated accurately prior to calibration. Further investigation is needed on more watersheds to determine SMAX 's ability to calibrate volume and timing with a constant set of other model parameter values. (USGS)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70031423','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70031423"><span>Trends and variability in <span class="hlt">snowmelt</span> runoff in the western United States</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>McCabe, G.J.; Clark, M.P.</p> <p>2005-01-01</p> <p>The timing of <span class="hlt">snowmelt</span> runoff (SMR) for 84 rivers in the western United States is examined to understand the character of SMR variability and the climate processes that may be driving changes in SMR timing. Results indicate that the timing of SMR for many rivers in the western United States has shifted to earlier in the <span class="hlt">snowmelt</span> season. This shift occurred as a step change during the mid-1980s in conjunction with a step increase in spring and early-summer atmospheric pressures and temperatures over the western United States. The cause of the step change has not yet been determined. ?? 2005 American Meteorological Society.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li class="active"><span>18</span></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_18 --> <div id="page_19" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li class="active"><span>19</span></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="361"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005AGUFMGC33B1255L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005AGUFMGC33B1255L"><span>The impact of climate change on the accuracy of <span class="hlt">streamflow</span> predictions in California</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Leonardson, R.; Vicuna, S.; Dracup, J. A.; Dale, L. L.</p> <p>2005-12-01</p> <p>Every spring, California's Department of Water Resources (DWR) forecasts <span class="hlt">streamflow</span> for the upcoming irrigation season (April-July) for rivers fed by the Western Sierra snowpack. The DWR forecasts influence water allocations, cropping strategy, and flood and drought management plans; forecast error can impact California's economy, especially the agricultural sector. Demand for water is expected to increase with population growth and climate change effects, in which the summers will be longer and hotter. At the same time, the percentage of precipitation falling as snow will shrink, and the snowpack is expected to melt earlier. We expect both of these factors to reduce forecast accuracy, as forecasting rainfall is less precise than measuring snowpack and because less of the snowpack will remain after April 1st. In this study, we examine relationships between historical forecast error and watershed elevation, snowpack size, <span class="hlt">snowmelt</span> timing (as hydrograph center-of-mass), and other factors. We quantify expected future error using the predictions of multiple global circulation models and various emissions scenarios.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.H11C1349W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.H11C1349W"><span>Ecohydrologic Response of a Wetland Indicator Species to Climate Change and <span class="hlt">Streamflow</span> Regulation: A Conceptual Model</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ward, E. M.; Gorelick, S.</p> <p>2015-12-01</p> <p>The Peace-Athabasca Delta ("Delta") in northeastern Alberta, Canada, is a UNESCO World Heritage Site and a Ramsar Wetland of International Importance. Delta ecohydrology is expected to respond rapidly to upstream water demand and climate change, with earlier spring meltwater, decreased springtime peak flow, and a decline in springtime ice-jam flooding. We focus on changes in the population and distribution of muskrat (Ondatra zibethicus), an ecohydrologic indicator species. We present a conceptual model linking hydrology and muskrat ecology. Our conceptual model links seven modules representing (1) upstream water demand, (2) <span class="hlt">streamflow</span> and <span class="hlt">snowmelt</span>, (3) floods, (4) the water balance of floodplain lakes, (5) muskrat habitat suitability, (6) wetland vegetation, and (7) muskrat population dynamics predicted using an agent-based model. Our goal is to evaluate the effects of different climate change and upstream water demand scenarios on the abundance and distribution of Delta muskrat, from present-2100. Moving from the current conceptual model to a predictive quantitative model, we will rely on abundant existing data and Traditional Ecological Knowledge of muskrat and hydrology in the Delta.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFM.H53A1667D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFM.H53A1667D"><span>Season-ahead <span class="hlt">streamflow</span> forecast informed tax strategies for semi-arid water rights markets</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Delorit, J. D.; Block, P. J.</p> <p>2016-12-01</p> <p>In many semi-arid regions multisectoral demands stress available water supplies. The Elqui River valley of north central Chile, which draws on limited capacity reservoirs supplied largely by annually variable <span class="hlt">snowmelt</span>, is one of these cases. This variability forces water managers to develop demand-based allocation strategies which have typically resulted in water right volume reductions, applied equally per right. Compounding this issue is often deferred or delayed infrastructure investments, which has been linked Chile's Coasian approach to water markets, under which rights holders do not pay direct procurement costs, non-use fees, nor taxes. Here we build upon our previous research using forecasts of likely water rights reductions, informed by season-ahead prediction models of October-January (austral growing season) <span class="hlt">streamflow</span>, to construct annual, forecast-sensitive, per right tax. We believe this tax, to be borne by right holders, will improve the beneficial use of water resources by stimulating water rights trading and improving system efficiency by generating funds for infrastructure investment, thereby reducing free-ridership and conflict between rights holders. Research outputs will include sectoral per right tax assessments, tax revenue generation, Elqui River valley economic output, and water rights trading activity.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.usgs.gov/pp/pp1703/d/','USGSPUBS'); return false;" href="https://pubs.usgs.gov/pp/pp1703/d/"><span><span class="hlt">Streamflow</span>, Infiltration, and Ground-Water Recharge at Abo Arroyo, New Mexico</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Stewart-Deaker, Amy E.; Stonestrom, David A.; Moore, Stephanie J.</p> <p>2007-01-01</p> <p>Abo Arroyo, an ephemeral tributary to the Rio Grande, rises in the largest upland catchment on the eastern side of the Middle Rio Grande Basin (MRGB). The 30-kilometer reach of channel between the mountain front and its confluence with the Rio Grande is incised into basin-fill sediments and separated from the regional water table by an unsaturated zone that reaches 120 meters thick. The MRGB portion of the arroyo is dry except for brief flows generated by runoff from the upland catchment. Though brief, ephemeral flows provide a substantial fraction of ground-water recharge in the southeastern portion of the MRGB. Previous estimates of average annual recharge from Abo Arroyo range from 1.3 to 21 million cubic meters. The current study examined the timing, location, and amount of channel infiltration using <span class="hlt">streamflow</span> data and environmental tracers during a four-year period (water years 1997?2000). A <span class="hlt">streamflow</span>-gaging station (?gage?) was installed in a bedrock-controlled reach near the catchment outlet to provide high-frequency data on runoff entering the basin. <span class="hlt">Streamflow</span> at the gage, an approximate bound on potential tributary recharge to the basin, ranged from 0.8 to 15 million cubic meters per year. Storm-generated runoff produced about 98 percent of the flow in the wettest year and 80 percent of the flow in the driest year. Nearly all flows that enter the MRGB arise from monsoonal storms in July through October. A newly developed streambed temperature method indicated the presence and duration of ephemeral flows downstream of the gage. During the monsoon season, abrupt downward shifts in streambed temperatures and suppressed diurnal ranges provided generally clear indications of flow. Streambed temperatures during winter showed that <span class="hlt">snowmelt</span> is also effective in generating channel infiltration. Controlled infiltration experiments in dry arroyo sediments indicated that most ephemeral flow is lost to seepage before reaching the Rio Grande. Streambed temperature</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2002EGSGA..27.2574H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2002EGSGA..27.2574H"><span>Quantifying The Effects of Initial Soil Moisture On Seasonal <span class="hlt">Streamflow</span> Forecasts In The Columbia River Basin</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hamlet, A. F.; Wood, A.; Lettenmaier, D. P.</p> <p></p> <p>The role of soil moisture storage in the hydrologic cycle is well understood at a funda- mental level. Antecedent conditions are known to have potentially significant effects on <span class="hlt">streamflow</span> forecasts, especially for short (e.g., flood) lead times. For this reason, the U.S. Geological Survey defines its "water year" as extending from October through September, a time period selected because over most of the U.S., soil moisture is at a seasonal low at summer's end. The effects of carryover soil moisture storage in the Columbia River basin have usually been considered to be minimal when forecasts are made on a water year or seasonal basis. Our study demonstrates that the role of carry- over soil moisture storage can be important. Absent direct observations of ET and soil moisture that would permit a closing of the water balance from observations, we use a physically based hydrologic model to estimate the soil moisture state at the begin- ning of the forecast period (Oct 1). We then evaluate, in a self-consistent manner, the subsequent effects of interannual variations in fall soil moisture on <span class="hlt">streamflow</span> during the subsequent spring and summer <span class="hlt">snowmelt</span> season (April-September). We analyze the period from 1950-1999, and the subsequent effects to the seasonal water balance at The Dalles, OR for representative high, medium, and low water years. The effects of initial soil state in fall are remarkably persistent, with significant effects occurring in the summer of the following water year. For a representative low flow year (1992), the simulated variability of the soil moisture state in September produces a range of summer <span class="hlt">streamflows</span> (April-September mean) equivalent to about 16 percent of the mean summer flows for all initial soil conditions, with analogous, but smaller, relative changes for medium and high flow years. Winter flows are also affected, and the rel- ative intensity of effects in winter and summer is variable, an effect that is probably attributable to the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.usgs.gov/sir/2009/5135/','USGSPUBS'); return false;" href="https://pubs.usgs.gov/sir/2009/5135/"><span>Statistical Summaries of <span class="hlt">Streamflow</span> in and near Oklahoma Through 2007</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Lewis, Jason M.; Esralew, Rachel A.</p> <p>2009-01-01</p> <p>Statistical summaries of <span class="hlt">streamflow</span> records through 2007 for gaging stations in Oklahoma and parts of adjacent states are presented for 238 stations with at least 10 years of <span class="hlt">streamflow</span> record. <span class="hlt">Streamflow</span> at 120 of the stations is regulated for specific periods. Data for these periods were analyzed separately to account for changes in <span class="hlt">streamflow</span> because of regulation by dams or other human modification of <span class="hlt">streamflow</span>. A brief description of the location, drainage area, and period of record is given for each gaging station. A brief regulation history also is given for stations with a regulated <span class="hlt">streamflow</span> record. This descriptive information is followed by tables of mean and median monthly and annual discharges, magnitude and probability of exceedance of annual instantaneous peak flows, durations of daily mean flow, magnitude and probability of nonexceedance of annual low flows, and magnitude and probability of nonexceedance of seasonal low flows.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70044662','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70044662"><span>Mississippi River <span class="hlt">streamflow</span> measurement techniques at St. Louis, Missouri</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Wastson, Chester C.; Holmes, Jr., Robert R.; Biedenham, David S.</p> <p>2013-01-01</p> <p><span class="hlt">Streamflow</span> measurement techniques of the Mississippi River at St. Louis have changed through time (1866–present). In addition to different methods used for discrete <span class="hlt">streamflow</span> measurements, the density and range of discrete measurements used to define the rating curve (stage versus <span class="hlt">streamflow</span>) have also changed. Several authors have utilized published water surface elevation (stage) and <span class="hlt">streamflow</span> data to assess changes in the rating curve, which may be attributed to be caused by flood control and/or navigation structures. The purpose of this paper is to provide a thorough review of the available flow measurement data and techniques and to assess how a strict awareness of the limitations of the data may affect previous analyses. It is concluded that the pre-1930s discrete <span class="hlt">streamflow</span> measurement data are not of sufficient accuracy to be compared with modern <span class="hlt">streamflow</span> values in establishing long-term trends of river behavior.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70019767','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70019767"><span>Regional <span class="hlt">streamflow</span> regimes and hydroclimatology of the United States</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Lins, H.F.</p> <p>1997-01-01</p> <p>The dominant regions of interannual <span class="hlt">streamflow</span> variability in the United States are defined, and their seasonality and persistence characteristics identified, using an orthogonally rotated principal components analysis (RPCA) of a climatically sensitive network of 559 stream gages for the period 1941-1988. This classification of <span class="hlt">streamflow</span> regimes is comprehensive and unique in that separate analyses of the <span class="hlt">streamflow</span> record, for each month of the year, are carried out to detail the month-to-month changes in the dominant <span class="hlt">streamflow</span> patterns. <span class="hlt">Streamflow</span> variations, or anomalies, in the Upper Mississippi, South Atlantic/Gulf, Far West, Ohio Valley, Northeast, and Eastern/Mid-Atlantic regions, as well as a pattern of opposing <span class="hlt">streamflow</span> anomalies in the West, are observed in all seasons of the year. Anomalies in the Southern Plains and New England regions are observed in autumn, winter, and spring; those in the Rocky Mountains and Middle Mississippi regions occur in late spring and summer.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..1912675S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..1912675S"><span>Monthly <span class="hlt">streamflow</span> forecasting in the Rhine basin</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Schick, Simon; Rössler, Ole; Weingartner, Rolf</p> <p>2017-04-01</p> <p>Forecasting seasonal <span class="hlt">streamflow</span> of the Rhine river is of societal relevance as the Rhine is an important water way and water resource in Western Europe. The present study investigates the predictability of monthly mean <span class="hlt">streamflow</span> at lead times of zero, one, and two months with the focus on potential benefits by the integration of seasonal climate predictions. Specifically, we use seasonal predictions of precipitation and surface air temperature released by the European Centre for Medium-Range Weather Forecasts (ECMWF) for a regression analysis. In order to disentangle forecast uncertainty, the 'Reverse Ensemble <span class="hlt">Streamflow</span> Prediction' framework is adapted here to the context of regression: By using appropriate subsets of predictors the regression model is constrained to either the initial conditions, the meteorological forcing, or both. An operational application is mimicked by equipping the model with the seasonal climate predictions provided by ECMWF. Finally, to mitigate the spatial aggregation of the meteorological fields the model is also applied at the subcatchment scale, and the resulting predictions are combined afterwards. The hindcast experiment is carried out for the period 1982-2011 in cross validation mode at two gauging stations, namely the Rhine at Lobith and Basel. The results show that monthly forecasts are skillful with respect to climatology only at zero lead time. In addition, at zero lead time the integration of seasonal climate predictions decreases the mean absolute error by 5 to 10 percentage compared to forecasts which are solely based on initial conditions. This reduction most likely is induced by the seasonal prediction of precipitation and not air temperature. The study is completed by bench marking the regression model with runoff simulations from ECMWFs seasonal forecast system. By simply using basin averages followed by a linear bias correction, these runoff simulations translate well to monthly <span class="hlt">streamflow</span>. Though the regression model</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.usgs.gov/of/1975/0673/report.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/of/1975/0673/report.pdf"><span>Climatic and <span class="hlt">streamflow</span> estimates for northeastern Utah</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Fields, Fred K.; Adams, D. Briane</p> <p>1976-01-01</p> <p>This report shows how information from 44 air-temperature, 59 precipitation, and 86 <span class="hlt">streamflow</span> sites was converted to a common-time base of 1941-70, and how general relations were developed to extend the converted point values to unsampled sites.Two methods, regression and ratio, were used to convert the data to a common-time base. Both methods require a period of concurrent data at two sites. After an estimating equation has been defined from concurrent data, the regression method requires data at the independent site only during the record voids of the dependent site. The independent site must have a complete record, however, if the ratio method is to be used.Regression techniques were used to fill voids in the air-temperature data base and to determine the correlation of monthly and annual averages, the average annual distribution, and equations that can be used to estimate average monthly and seasonal air temperature, precipitation, and <span class="hlt">streamflow</span>. Incomplete precipitation and <span class="hlt">streamflow</span> records were adjusted to the 1941-70 average on the assumption that the ratio of con- current data is directly proportional to the ratio of the respective 1941-70 average annual values at nearby sites.The average monthly air temperature at a short-term collection site generally can be approximated with a standard error of estimate of less than 2 degrees Fahrenheit (1.1 degrees Celsius). The standard deviation of the precipitation residuals, about the averages of the estimates for all incomplete-record sites, is 0.42 inch (11 millimetres). The average annual precipitation at the 59 sites used in this analysis is 16.2 inches (411 millimetres). Two-thirds of the <span class="hlt">streamflow</span> estimates are within 13.0 cubic feet per second (0.37 cubic metres per second) of the averages of the site estimates, which is about 10 percent of the sample average.Altitude and location can be used to estimate the average annual temperature and precipitation. Schematic diagrams, plotted by computer, were</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.fs.usda.gov/treesearch/pubs/43581','TREESEARCH'); return false;" href="https://www.fs.usda.gov/treesearch/pubs/43581"><span>Severe soil frost reduced losses of carbon and nitrogen from the forest floor during simulated <span class="hlt">snowmelt</span>: A laboratory experiment</span></a></p> <p><a target="_blank" href="http://www.fs.usda.gov/treesearch/">Treesearch</a></p> <p>Andrew B. Reinmann; Pamela H. Templer; John L. Campbell</p> <p>2012-01-01</p> <p>Considerable progress has been made in understanding the impacts of soil frost on carbon (C) and nitrogen (N) cycling, but the effects of soil frost on C and N fluxes during <span class="hlt">snowmelt</span> remain poorly understood. We conducted a laboratory experiment to determine the effects of soil frost on C and N fluxes from forest floor soils during <span class="hlt">snowmelt</span>. Soil cores were collected...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFM.H51B1336D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFM.H51B1336D"><span>Hydrologic response to modeled <span class="hlt">snowmelt</span> input in alpine catchments in the Southwestern United States</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Driscoll, J. M.; Molotch, N. P.; Jepsen, S. M.; Meixner, T.; Williams, M. W.; Sickman, J. O.</p> <p>2012-12-01</p> <p><span class="hlt">Snowmelt</span> from high elevation catchments is the primary source of water resources in the Southwestern United States. Timing and duration of <span class="hlt">snowmelt</span> and resulting catchment response can show the physical and chemical importance of storage at the catchment scale. Storage of waters in subsurface materials provides a physical and chemical buffer to hydrologic input variability. We expect the hydrochemistry of catchments with less storage capacity will more closely reflect input waters than a catchment with more storage and therefore more geochemical evolution of waters. Two headwater catchments were compared for this study; Emerald Lake Watershed (ELW) in the southern Sierra Nevada and Green Lake 4 (GL4) in the Colorado Front Range. These sites have geochemically similar granitic terrane, and negligible evaporation and transpiration due to their high-elevation setting. Eleven years of data (1996-2006) from spatially-distributed <span class="hlt">snowmelt</span> models were spatially and temporally aggregated to generate daily values of <span class="hlt">snowmelt</span> volume for each catchment area. Daily storage flux was calculated as the difference between <span class="hlt">snowmelt</span> input and catchment outflow at a daily timestep, normalized to the catchment area. Daily <span class="hlt">snowmelt</span> values in GL4 are more consistent (the annual standard deviation ranged from 0.19 to 0.76 cm) than the daily <span class="hlt">snowmelt</span> in ELW (0.60 to 1.04 cm). Outflow follows the same trend, with an even narrower range of standard deviations from GL4 (0.27 to 0.54 cm) compared to the standard deviation of outflow in ELW (0.38 to 0.98 cm). The dampening of the input variability could be due to storage in the catchment; the larger effect would mean a larger storage capacity in the catchment. Calculations of storage flux (the input <span class="hlt">snowmelt</span> minus the output catchment discharge) show the annual sum of water into storage in ELW ranges from -0.9200 to 1.1124 meters, in GL4 the ranger is narrower, from -0.655 to 0.0992 meters. Cumulative storage for each year can be negative</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://link.springer.com/article/10.1007/s10584-013-1042-7/fulltext.html','USGSPUBS'); return false;" href="http://link.springer.com/article/10.1007/s10584-013-1042-7/fulltext.html"><span>Assessing <span class="hlt">streamflow</span> sensitivity to variations in glacier mass balance</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>O'Neel, Shad; Hood, Eran; Arendt, Anthony; Sass, Louis</p> <p>2014-01-01</p> <p>The purpose of this paper is to evaluate relationships among seasonal and annual glacier mass balances, glacier runoff and <span class="hlt">streamflow</span> in two glacierized basins in different climate settings. We use long-term glacier mass balance and <span class="hlt">streamflow</span> datasets from the United States Geological Survey (USGS) Alaska Benchmark Glacier Program to compare and contrast glacier-<span class="hlt">streamflow</span> interactions in a maritime climate (Wolverine Glacier) with those in a continental climate (Gulkana Glacier). Our overall goal is to improve our understanding of how glacier mass balance processes impact <span class="hlt">streamflow</span>, ultimately improving our conceptual understanding of the future evolution of glacier runoff in continental and maritime climates.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016WRR....52.1465B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016WRR....52.1465B"><span>A regional estimate of postfire <span class="hlt">streamflow</span> change in California</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bart, Ryan R.</p> <p>2016-02-01</p> <p>The effect of fire on annual <span class="hlt">streamflow</span> has been examined in numerous watershed studies, with some studies observing postfire increases in <span class="hlt">streamflow</span> while other have observed no conclusive change. Despite this inherent variability in <span class="hlt">streamflow</span> response, the management of water resources for flood protection, water supply, water quality, and the environment necessitates an understanding of postfire effects on <span class="hlt">streamflow</span> at regional scales. In this study, the regional effect of wildfire on annual <span class="hlt">streamflow</span> was investigated using 12 paired watersheds in central and southern California. A mixed model was used to pool and statistically examine the combined paired-watershed data, with emphasis on the effects of percentage area burned, postfire recovery of vegetation, and postfire wetness conditions on postfire <span class="hlt">streamflow</span> change. At a regional scale, postfire annual <span class="hlt">streamflow</span> increased 134% (82%-200%) during the first postfire year assuming 100% area burned and average annual wetness conditions. Postfire response decreased with lower percentages of percentage area burned and during subsequent years as vegetation recovered following fire. Annual <span class="hlt">streamflow</span> response to fire was found to be sensitive to annual wetness conditions, with postfire response being smallest during dry years, greatest during wet years, and slowly decreasing during very wet years. These findings provide watershed managers with a first-order estimate for predicting postfire <span class="hlt">streamflow</span> response in both gauged and ungauged watersheds.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25115604','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25115604"><span>Drivers influencing <span class="hlt">streamflow</span> changes in the Upper Turia basin, Spain.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Salmoral, Gloria; Willaarts, Bárbara A; Troch, Peter A; Garrido, Alberto</p> <p>2015-01-15</p> <p>Many rivers across the world have experienced a significant <span class="hlt">streamflow</span> reduction over the last decades. Drivers of the observed <span class="hlt">streamflow</span> changes are multiple, including climate change (CC), land use and land cover changes (LULCC), water transfers and river impoundment. Many of these drivers inter-act simultaneously, making it difficult to discern the impact of each driver individually. In this study we isolate the effects of LULCC on the observed <span class="hlt">streamflow</span> reduction in the Upper Turia basin (east Spain) during the period 1973-2008. Regression models of annual <span class="hlt">streamflow</span> are fitted with climatic variables and also additional time variant drivers like LULCC. The ecohydrological model SWAT is used to study the magnitude and sign of <span class="hlt">streamflow</span> change when LULCC occurs. Our results show that LULCC does play a significant role on the water balance, but it is not the main driver underpinning the observed reduction on Turia's <span class="hlt">streamflow</span>. Increasing mean temperature is the main factor supporting increasing evapotranspiration and <span class="hlt">streamflow</span> reduction. In fact, LULCC and CC have had an offsetting effect on the <span class="hlt">streamflow</span> generation during the study period. While <span class="hlt">streamflow</span> has been negatively affected by increasing temperature, ongoing LULCC have positively compensated with reduced evapotranspiration rates, thanks to mainly shrubland clearing and forest degradation processes. These findings are valuable for the management of the Turia river basin, as well as a useful approach for the determination of the weight of LULCC on the hydrological response in other regions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/5844573','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/5844573"><span>Lack of bioaccumulation of metals by Elliptio complanata (Bivalvia) during acidic <span class="hlt">snowmelt</span> in three south-central Ontario streams</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Servos, M.R.; Malley, D.F.; Mackie, G.L.; LaZerte, B.D.</p> <p>1987-05-01</p> <p>Depression of pH and elevation of metals during spring <span class="hlt">snowmelt</span> may be widespread. However, because of the episodic nature of these events they are very difficult to measure or even detect. Sampling of <span class="hlt">snowmelt</span> at regular intervals of only a few days, may not be adequate to detect short-term variations in pH and metal concentrations. The objective of the present study was to determine the feasibility of using biomonitoring to detect short-term changes in concentration or bioavailability of metals (Al, Zn, Cd) during spring <span class="hlt">snowmelt</span>. Unionid clams, (Elliptio complanata) were held in three south-central Ontario streams during the spring <span class="hlt">snowmelt</span> period of 1982. The gill tissues accumulate metals more readily than other tissues and thus are better biomonitors of available metals than whole body concentrations of these elements. Therefore, the concentration of metals in soft tissues (gill, body, foot) were compared separately to the stream water chemistry during <span class="hlt">snowmelt</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70026847','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70026847"><span>Spring onset in the Sierra Nevada: When is <span class="hlt">snowmelt</span> independent of elevation?</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Lundquist, J.D.; Cayan, D.R.; Dettinger, M.D.</p> <p>2004-01-01</p> <p>Short-term climate and weather systems can have a strong influence on mountain <span class="hlt">snowmelt</span>, sometimes overwhelming the effects of elevation and aspect. Although most years exhibit a spring onset that starts first at lowest and moves to highest elevations, in spring 2002, flow in a variety of streams within the Tuolumne and Merced River basins of the southern Sierra Nevada all rose synchronously on 29 March. Flow in streams draining small high-altitude glacial subcatchments rose at the same time as that draining much larger basins gauged at lower altitudes, and streams from north- and south-facing cirques rose and fell together. Historical analysis demonstrates that 2002 was one among only 8 yr with such synchronous flow onsets during the past 87 yr, recognized by having simultaneous onsets of <span class="hlt">snowmelt</span> at over 70% of snow pillow sites, having discharge in over 70% of monitored streams increase simultaneously, and having temperatures increase over 12??C within a 5-day period. Synchronous springs tend to begin with a low pressure trough over California during late winter, followed by the onset of a strong ridge and unusually warm temperatures. Synchronous springs are characterized by warmer than average winters and cooler than average March temperatures in California. In the most elevation-dependent, nonsynchronous years, periods of little or no storm activity, with warmer than average March temperatures, precede the onset of spring <span class="hlt">snowmelt</span>, allowing elevation and aspect to influence <span class="hlt">snowmelt</span> as spring arrives gradually. ?? 2004 American Meteorological Society.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.fs.usda.gov/treesearch/pubs/34360','TREESEARCH'); return false;" href="https://www.fs.usda.gov/treesearch/pubs/34360"><span>Alkalinity generation in <span class="hlt">snowmelt</span> and rain runoff during short distance flow over rock</span></a></p> <p><a target="_blank" href="http://www.fs.usda.gov/treesearch/">Treesearch</a></p> <p>James L. Clayton</p> <p>1998-01-01</p> <p>High-elevation ecosystems in the western United States typically have patchy, discontinuous areas of surficial soils surrounded by large areas of rock outcrop, talus, and scree. <span class="hlt">Snowmelt</span> and precipitation that percolate through soil increase in alkalinity, principally by increasing base cation concentration through cation exchange, and by decreasing acid anion...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26744921','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26744921"><span>Stream Nitrogen Inputs Reflect Groundwater Across a <span class="hlt">Snowmelt</span>-Dominated Montane to Urban Watershed.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Hall, Steven J; Weintraub, Samantha R; Eiriksson, David; Brooks, Paul D; Baker, Michelle A; Bowen, Gabriel J; Bowling, David R</p> <p>2016-02-02</p> <p><span class="hlt">Snowmelt</span> dominates the hydrograph of many temperate montane streams, yet little work has characterized how streamwater sources and nitrogen (N) dynamics vary across wildland to urban land use gradients in these watersheds. Across a third-order catchment in Salt Lake City, Utah, we asked where and when groundwater vs shallow surface water inputs controlled stream discharge and N dynamics. Stream water isotopes (δ(2)H and δ(18)O) reflected a consistent <span class="hlt">snowmelt</span> water source during baseflow. Near-chemostatic relationships between conservative ions and discharge implied that groundwater dominated discharge year-round across the montane and urban sites, challenging the conceptual emphasis on direct stormwater inputs to urban streams. Stream and groundwater NO3(-) concentrations remained consistently low during <span class="hlt">snowmelt</span> and baseflow in most montane and urban stream reaches, indicating effective subsurface N retention or denitrification and minimal impact of fertilizer or deposition N sources. Rather, NO3(-) concentrations increased 50-fold following urban groundwater inputs, showing that subsurface flow paths potentially impact nutrient loading more than surficial land use. Isotopic composition of H2O and NO3(-) suggested that <span class="hlt">snowmelt</span>-derived urban groundwater intercepted NO3(-) from leaking sewers. Sewer maintenance could potentially mitigate hotspots of stream N inputs at mountain/valley transitions, which have been largely overlooked in semiarid urban ecosystems.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/918114','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/918114"><span>An Analysis of Climate Variability and <span class="hlt">Snowmelt</span> Mechanisms inMountainous Regions</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>jimingjin@lbl.gov</p> <p>2003-09-26</p> <p>The impacts of snowpack on climate variability and themechanisms of <span class="hlt">snowmelt</span> over the Sierra Nevada, California-Nevadamountainous region was studied using the Penn State-National Center forAtmospheric Research fifth-generation Mesoscale Model (MM5) driven by6-hour reanalysis data from the National Centers for EnvironmentalPrediction. The analyses of a one-way nested 48 km to 12 km model runduring the 1998 <span class="hlt">snowmelt</span> season (April - June) shows that snowpack isunderestimated when there is stronger precipitation and highertemperature. Model resolution and simulated snowpack are found to affectthe temperature and precipitation. Coarser resolution underestimates thetopographic elevation in the Sierra Nevada, increasing the surface airtemperature and precipitation in light of the lapse rate and the rainshadow effect. An observed daily snowpack dataset, assimilated to MM5,reduces the warm bias, because the energy used to increase temperature ina model run without assimilated snow is consumed by <span class="hlt">snowmelt</span>. The cooledsurface leads to a more stable simulated atmosphere, leading to areduction in the exaggerated precipitation. An underestimated surfacealbedo weakly contributes to the stronger <span class="hlt">snowmelt</span>. A more realisticphysically-based land-surface model with sophisticated snow andvegetation physics driven by the MM5 output is shown to significantlyimprove the snowpack simulation.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li class="active"><span>19</span></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_19 --> <div id="page_20" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li class="active"><span>20</span></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="381"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.fs.usda.gov/treesearch/pubs/12982','TREESEARCH'); return false;" href="https://www.fs.usda.gov/treesearch/pubs/12982"><span>Aspen clearcutting increases <span class="hlt">snowmelt</span> and storm flow peaks in north central Minnesota</span></a></p> <p><a target="_blank" href="http://www.fs.usda.gov/treesearch/">Treesearch</a></p> <p>Elon S. Verry; Jeffrey R. Lewis; Kenneth N. Brooks</p> <p>1983-01-01</p> <p>Clearcutting aspen from the upland portion of an upland peatland watershed in north central Minnesota caused <span class="hlt">snowmelt</span> peak discharge to increase 11 to 143 percent. Rainfall peak discharge size increased as much as 250 percent during the first two years after clearcutting, then decreased toward precutting levels in subsequent years. Storm flow volumes from rain during...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ars.usda.gov/research/publications/publication/?seqNo115=259903','TEKTRAN'); return false;" href="http://www.ars.usda.gov/research/publications/publication/?seqNo115=259903"><span>Sensitivity of the <span class="hlt">snowmelt</span> runoff model to underestimates of remotely sensed snow covered area</span></a></p> <p><a target="_blank" href="https://www.ars.usda.gov/research/publications/find-a-publication/">USDA-ARS?s Scientific Manuscript database</a></p> <p></p> <p></p> <p>Three methods for estimating snow covered area (SCA) from Terra MODIS data were used to derive conventional depletion curves for input to the <span class="hlt">Snowmelt</span> Runoff Model (SRM). We compared the MOD10 binary and fractional snow cover products and a method for estimating sub-pixel snow cover using spectral m...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ars.usda.gov/research/publications/publication/?seqNo115=320429','TEKTRAN'); return false;" href="http://www.ars.usda.gov/research/publications/publication/?seqNo115=320429"><span>Evaluating MODIS snow products for modelling <span class="hlt">snowmelt</span> runoff: case study of the Rio Grande headwaters</span></a></p> <p><a target="_blank" href="https://www.ars.usda.gov/research/publications/find-a-publication/">USDA-ARS?s Scientific Manuscript database</a></p> <p></p> <p></p> <p>Snow-covered area (SCA) is a key variable in the <span class="hlt">Snowmelt</span>-Runoff Model (SRM). Landsat Thematic Mapper (TM) or Operational Land Imager (OLI) provide remotely sensed data at an appropriate spatial resolution for mapping SCA in small headwater basins, but the temporal resolution of the data is low and ...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.fs.usda.gov/treesearch/pubs/13237','TREESEARCH'); return false;" href="https://www.fs.usda.gov/treesearch/pubs/13237"><span>Mobility of nitrogen-15-labeled nitrate and sulfur-34-labeled sulfate during <span class="hlt">snowmelt</span></span></a></p> <p><a target="_blank" href="http://www.fs.usda.gov/treesearch/">Treesearch</a></p> <p>John L. Campbell; Myron J. Mitchell; Bernhard Mayer; Peter M. Groffman; Lynn M. Christenson</p> <p>2007-01-01</p> <p>The objective of this study was to investigate the winter dynamics of SO42− and NO3− in a forested soil to better understand controls on these acidifying anions during <span class="hlt">snowmelt</span>. In February 2004, a stable isotopic tracer solution with 93 atom% 34...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012JGRD..11710110J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012JGRD..11710110J"><span>Evaluation of <span class="hlt">snowmelt</span> simulation in the Weather Research and Forecasting model</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jin, Jiming; Wen, Lijuan</p> <p>2012-05-01</p> <p>The objective of this study is to better understand and improve <span class="hlt">snowmelt</span> simulations in the advanced Weather Research and Forecasting (WRF) model by coupling it with the Community Land Model (CLM) Version 3.5. Both WRF and CLM are developed by the National Center for Atmospheric Research. The automated Snow Telemetry (SNOTEL) station data over the Columbia River Basin in the northwestern United States are used to evaluate <span class="hlt">snowmelt</span> simulations generated with the coupled WRF-CLM model. These SNOTEL data include snow water equivalent (SWE), precipitation, and temperature. The simulations cover the period of March through June 2002 and focus mostly on the <span class="hlt">snowmelt</span> season. Initial results show that when compared to observations, WRF-CLM significantly improves the simulations of SWE, which is underestimated when the release version of WRF is coupled with the Noah and Rapid Update Cycle (RUC) land surface schemes, in which snow physics is oversimplified. Further analysis shows that more realistic snow surface energy allocation in CLM is an important process that results in improved <span class="hlt">snowmelt</span> simulations when compared to that in Noah and RUC. Additional simulations with WRF-CLM at different horizontal spatial resolutions indicate that accurate description of topography is also vital to SWE simulations. WRF-CLM at 10 km resolution produces the most realistic SWE simulations when compared to those produced with coarser spatial resolutions in which SWE is remarkably underestimated. The coupled WRF-CLM provides an important tool for research and forecasts in weather, climate, and water resources at regional scales.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26259440','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26259440"><span>[Soil infiltration of <span class="hlt">snowmelt</span> water in the southern Gurbantunggut Desert, Xinjiang, China].</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Hu, Shun-jun; Chen, Yong-bao; Zhu, Hai</p> <p>2015-04-01</p> <p>Soil infiltration of <span class="hlt">snow-melt</span> water is an important income item of water balance in arid desert. The soil water content in west slope, east slope and interdune of sand dune in the southern Gurbantunggut Desert was monitored before snowfall and after snow melting during the winters of 2012-2013 and 2013-2014. According to the principle of water balance, soil infiltration of <span class="hlt">snow-melt</span> in the west slope, east slope, interdune and landscape scale was calculated, and compared with the results measured by cylinder method. The results showed that the soil moisture recharge from unfrozen layer of unsaturated soil to surface frozen soil was negligible because the soil moisture content before snowfall was lower, soil infiltration of <span class="hlt">snow-melt</span> water was the main source of soil water of shallow soil, phreatic water did not evaporate during freezing period, and did not get recharge after the snow melting. <span class="hlt">Snowmelt</span> water in the west slope, east slope, interdune and landscape scale were 20-43, 27-43, 32-45, 26-45 mm, respectively.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70012063','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70012063"><span>The effect of <span class="hlt">snowmelt</span> on the water quality of Filson Creek and Omaday Lake, northeastern Minnesota.</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Siegel, D.I.</p> <p>1981-01-01</p> <p>Sulfate concentration and pH were determined in surface water, groundwater, and precipitation samples collected in the Filson Creek watershed to evaluate the sources of sulfate in Filson Creek. During and immediately after <span class="hlt">snowmelt</span>, sulfate concentrations in Filson Creek increased from about 2 to 14 mg/l.-from Author</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.usgs.gov/wri/1996/4291/report.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/wri/1996/4291/report.pdf"><span>Evaluation of <span class="hlt">streamflow</span> traveltime and <span class="hlt">streamflow</span> gains and losses along the lower Purgatoire River, southeastern Colorado, 1984-92</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Dash, R.G.; Edelmann, P.R.</p> <p>1997-01-01</p> <p>Traveltime and gains and losses within a stream are important basic characteristics of <span class="hlt">streamflow</span>. The lower Purgatoire River flows more than 160 river miles from Trinidad to the Arkansas River near Las Animas. A better knowledge of <span class="hlt">streamflow</span> traveltime and <span class="hlt">streamflow</span> gains and losses along the lower Purgatoire River would enable more informed management decisions about the availability of water supplies for irrigation use in southeastern Colorado. In 1994-95, the U.S.\\x11Geological Survey, in cooperation with the Purgatoire River Water Conservancy District and the Arkansas River Compact Administration, evaluated <span class="hlt">streamflow</span> traveltime and estimated <span class="hlt">streamflow</span> gains and losses using historical surface-water records. Traveltime analyses were used along the lower Purgatoire River to determine when <span class="hlt">streamflows</span> would arrive at selected downstream sites. The substantial effects of diversions for irrigation and unmeasured return flows in the most upstream reach of the river prevented the tracking of <span class="hlt">streamflow</span> through reach\\x111. Therefore, the estimation of <span class="hlt">streamflow</span> traveltime for the 60.6 miles of river downstream from Trinidad could not be made.Hourly <span class="hlt">streamflow</span> data from 1990 through 1994 were used to estimate traveltimes of more than 30 <span class="hlt">streamflow</span> events for about 100 miles of the lower Purgatoire River. In the middle reach of the river, the traveltime of <span class="hlt">streamflow</span> for the 40.1\\x11miles ranged from about 11 to about 47\\x11hours, and in the lower reach of the river, traveltime for the 58.5 miles ranged from about 6 to about 61 hours.Traveltime in the river reaches generally increased as <span class="hlt">streamflow</span> decreased, but also varied for a specific <span class="hlt">streamflow</span> in both reaches. <span class="hlt">Streamflow</span> gains and losses were estimated using daily <span class="hlt">streamflow</span> data at the upstream and downstream sites, available tributary inflow data, and daily diversion data. Differences between surface-water inflows and surface-water outflows in a reach determined the quantity of water gained or lost. In</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.C33C0838N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.C33C0838N"><span>Impact of Mountain Pine Beetle Infestation on <span class="hlt">Snowmelt</span>: Variations with Vegetation Structure and Geographical Locations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ni-Meister, W.</p> <p>2015-12-01</p> <p>The warming climate resulted in the current outbreak of mountain pine beetles (MPB) in western and northwestern US. and Western Canada. Colorado, Wyoming, South Dakota, Nebraska, and British Columbia are also currently experiencing widespread mountain pine beetle infestations. Forest disturbance due to MPB can have a large impact on hydrological processes specifically snow accumulation and <span class="hlt">snowmelt</span>. In those regions, spring <span class="hlt">snowmelt</span> is a major water resource and MPB infestations can have a big impact on water resource management. MPB infestations cause forest canopies to gradually diminish over the course of several years, they therefore impact snow interception and radiation balance at snow surface, thus <span class="hlt">snowmelt</span>. Past studies on this topic have achieved contradicting results. This study focuses on understanding how the impacts of MPB infestations on snow surface radiation balance and <span class="hlt">snowmelt</span> rates vary with vegetation structure and geographical locations. We selected four sites in northern Colorado and four sites in the Cascade Mountains in Oregon with varying intensities of MPB. Snow Water Equivalent (SWE) data from SNOTEL sites and MPB-caused forest disturbance data extracted from Landsat time series disturbance maps were used for our analysis. Our results show that MPB sites show larger snow accumulation for sites in Colorado and Cascade Mountains. However <span class="hlt">snowmelt</span> rate varies differently. For sites in Colorado, snow melts faster in the MPB sites than in the healthy forest sites. In contrary, in the Cascade Mountains, snow stays longer in MPB sites than in healthy and undisturbed sites. Our modeling study shows that shortwave radiation is a dominant factor for radiation balance in the mid-latitude region (Colorado). There, MPB infestations lead to increased shortwave radiation and faster <span class="hlt">snowmelt</span>. However, long wave radiation plays an important role for radiation balance in high latitude areas. MPB infestations decrease longwave radiation and result in snow</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.H51D0644H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.H51D0644H"><span>The Sensitivity of Soil Moisture in Western U.S. Mountains to Changes in <span class="hlt">Snowmelt</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Harpold, A. A.</p> <p>2014-12-01</p> <p><span class="hlt">Snowmelt</span> is the primary water source for human needs and ecosystems services in much of the Western U.S. Regional warming is expected to hasten snow disappearance and reduce snowpacks. The soil water budget strongly mediates the effects of changing <span class="hlt">snowmelt</span> patterns by storing water and altering is partitioning to evaporation, transpiration, and runoff. This study therefore asked the research question, "Under what conditions was soil water availability coupled to <span class="hlt">snowmelt</span> magnitudes and timing across Western U.S. mountains?" We posed three potential hypotheses to explain decoupling between soil water availability and <span class="hlt">snowmelt</span>: 1. Contributions from post-<span class="hlt">snowmelt</span> rainfall, 2. Longer growing season length and/or greater water demand, and/or 3. Insufficient soil water storage. Using 259 Snow Telemetry (SNOTEL) stations, we showed that the timing of Peak Soil Moisture (PSM) was strongly explained by snow disappearance (Pearson r-value of 0.62). However, differences in the coupling of PSM with DSD were dependent on soil and bedrock type, with well-drained areas having earlier PSM relative to DSD. A second analysis focused on 48 SNOTEL and Soil Climate Analysis Network (SCAN) stations in the Northwest and Intermountain Western U.S. where detailed soil hydraulic properties existed. We found the timing of snow disappearance was a strong influence (p<0.01) on the number of days per year that soil moisture was below wilting point at individual stations, whereas summer precipitation was a weaker predictor. We develop a framework to classify stations into three classes: 1. stations that were not subject to water stress from changing <span class="hlt">snowmelt</span> patterns over the historical records, 2. stations subject to water stress during poor <span class="hlt">snowmelt</span> years, and 3. stations that relied on rainfall to avoid water stress across historical records. Our combined results demonstrate that snow disappearance timing is a first-order control on soil water availability across many Western U.S. mountain</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006AGUFM.C13A..06A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006AGUFM.C13A..06A"><span>AMSR-E Algorithm for <span class="hlt">Snowmelt</span> Onset Detection in Subarctic Heterogeneous Terrain</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Apgar, J. D.; Ramage, J. M.; McKenney, R. A.; Kopczynski, S. E.; Haight, S. L.; Maltais, P.</p> <p>2006-12-01</p> <p><span class="hlt">Snowmelt</span> onset in the mixed terrain of the upper Yukon River basin, Canada, can be derived from brightness temperatures (Tb) obtained by the Advanced Microwave Scanning Radiometer for EOS (AMSR-E) on NASA's Aqua satellite. AMSR-E, with a resolution of 14 x 8 km2 for the 36.5 GHz frequency and two to four observations per day, improves upon the twice-daily coverage (EASE-Grid) and 37 x 28 km2 spatial resolution of the Special Sensor Microwave Imager (SSM/I). The onset of melt within a snowpack causes an increase in the daytime 36.5 GHz vertically polarized Tb as well as a shift to high diurnal amplitude variations (DAV) as the snow melts during the day and refreezes at night. The higher temporal and spatial resolutions, as well as the timing of data acquisition, make AMSR-E more sensitive than SSM/I to sub-daily Tb oscillations, resulting in DAV that show a greater daily range compared to SSM/I. Using ground- based surface temperature and snowpack wetness to verify satellite interpretations, the <span class="hlt">snowmelt</span> thresholds of Tb > 246 K and DAV > ±10 K developed for use with SSM/I have been adjusted for detecting melt onset with AMSR-E to Tb > 252 K and DAV > ±18 K. AMSR-E derived <span class="hlt">snowmelt</span> onset correspond with SSM/I observations in the small subarctic Wheaton River basin (~60°08'05"N, ~134°53'45"W) through the 2004 and 2005 spring transitions. Snowpack wetness measurements collected in the Wheaton basin during the spring of 2005 relate well with temporally-corresponding AMSR-E Tb and the established <span class="hlt">snowmelt</span> thresholds. The enhanced resolution of AMSR-E is more effective than SSM/I at delineating both spatial and temporal <span class="hlt">snowmelt</span> dynamics in the heterogeneous terrain of the upper Yukon River basin. The use of this AMSR-E <span class="hlt">snowmelt</span> onset algorithm in other areas of the subarctic will ultimately allow for a more thorough examination of the impact of spring <span class="hlt">snowmelt</span> upon basin hydrology and regional climate.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AGUFM.C33F0603C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AGUFM.C33F0603C"><span>The Effect of Soil Freezing on Nitrogen and Carbon in Soil Leachate during <span class="hlt">Snowmelt</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Campbell, J. L.; Templer, P. H.; Reinmann, A.</p> <p>2010-12-01</p> <p>Climate change is altering seasonal snow cover and soil frost, having implications for the hydrology, biology and chemistry of terrestrial ecosystems. Soil freezing events influence the production and mobilization of carbon (C) and nitrogen (N), yet the controlling processes have not been clearly identified. We conducted a mesocosm study to evaluate the impact of soil freezing on the sources and processing of C and N during <span class="hlt">snowmelt</span>. Cores from the forest floor were collected from sugar maple, American beech and spruce-fir stands at the Hubbard Brook Experimental Forest in New Hampshire. The cores were placed in PVC columns, reinserted in the holes, and left in the field over winter to equilibrate. The columns were extracted the following spring and brought back to the laboratory where they were subjected to a soil temperature treatment representing either a hard frost (-15 °C), a mild frost (-0.5 °C), or above freezing conditions (5 °C). The columns were filled with equal amounts of snow and moved to a cold room maintained at 5 °C to simulate spring <span class="hlt">snowmelt</span>. Soil temperatures in the three treatments remained near 0 °C throughout the <span class="hlt">snowmelt</span> period. The melting snow leached through the soil columns and was collected in sample bottles. Snow and soil leachate were analyzed for NO3-N, NH4-N, DON, DOC, SUVA254, δ15N-NO3, and δ18O-NO3. The snow in the columns subjected to the +5.0 and -0.5 °C treatments melted steadily at similar rates. In contrast, melting snow ponded on top of the soils subjected to the hard freeze treatment (-15.0 °C) and then quickly passed through the column when the soil thawed. Mass balances of water, N, and C were developed to compare the inputs in <span class="hlt">snowmelt</span> with the outputs in leachate. The soil was saturated at the beginning of the experiment so the volume of water collected in leachate was nearly equivalent to the volume of water in snow that was added to each column. Outputs of NO3-N and NH4-N in soil leachate from sugar maple</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005AGUFM.H21A1312T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005AGUFM.H21A1312T"><span>Coupled Oceanic / Atmospheric Variability and United States <span class="hlt">Streamflow</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tootle, G.; Piechota, T.</p> <p>2005-12-01</p> <p>A study of the influence of interdecadal, decadal and interannual oceanic / atmospheric influences on <span class="hlt">streamflow</span> in the U.S. is presented. Unimpaired <span class="hlt">streamflow</span> was identified for 639 stations in the U.S. for the period 1951 - 2002. The phase (cold / negative or warm / positive) of Pacific Ocean [El Niño-Southern Oscillation (ENSO) and Pacific Decadal Oscillation (PDO)] and Atlantic Ocean [Atlantic Multidecadal Oscillation (AMO) and North Atlantic Oscillation (NAO)] oceanic / atmospheric influences were identified for the year prior to the <span class="hlt">streamflow</span> year (i.e., long lead-time). Statistical significance testing of <span class="hlt">streamflow</span>, based on the interdecadal, decadal and interannual oceanic / atmospheric phase (warm / positive or cold / negative), was performed applying the nonparametric rank-sum test. The results show that, in addition to the well-established ENSO signal, the PDO, AMO and NAO influence <span class="hlt">streamflow</span> variability in the United States. The warm phase of the PDO is associated with increased <span class="hlt">streamflow</span> in the central and southwest U.S. while the warm phase of the AMO is associated with reduced <span class="hlt">streamflow</span> in these regions. The positive phase of the NAO and the cold phase of the AMO are associated with increased <span class="hlt">streamflow</span> in the central United States. Additionally, the coupled effects of the oceanic / atmospheric influences were evaluated, based on the long-term phase (cold / negative or warm / positive) of the interdecadal (PDO and AMO) and decadal (NAO) influences and ENSO. <span class="hlt">Streamflow</span> regions in the U.S. were identified that respond to these climatic couplings. The results show that the AMO may influence La Niña impacts in the Southeast while the NAO may influence La Niña impacts in the Midwest. By utilizing the <span class="hlt">streamflow</span> water year and the long lead-time for the oceanic / atmospheric variables, useful information can be provided to <span class="hlt">streamflow</span> forecasters and water managers.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005WRR....4112408T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005WRR....4112408T"><span>Coupled oceanic-atmospheric variability and U.S. <span class="hlt">streamflow</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tootle, Glenn A.; Piechota, Thomas C.; Singh, Ashok</p> <p>2005-12-01</p> <p>A study of the influence of interdecadal, decadal, and interannual oceanic-atmospheric influences on <span class="hlt">streamflow</span> in the United States is presented. Unimpaired <span class="hlt">streamflow</span> was identified for 639 stations in the United States for the period 1951-2002. The phases (cold/negative or warm/positive) of Pacific Ocean (El Niño-Southern Oscillation (ENSO) and Pacific Decadal Oscillation (PDO)) and Atlantic Ocean (Atlantic Multidecadal Oscillation (AMO) and North Atlantic Oscillation (NAO)) oceanic-atmospheric influences were identified for the year prior to the <span class="hlt">streamflow</span> year (i.e., long lead time). Statistical significance testing of <span class="hlt">streamflow</span>, based on the interdecadal, decadal, and interannual oceanic-atmospheric phase (warm/positive or cold/negative), was performed by applying the nonparametric rank-sum test. The results show that in addition to the well-established ENSO signal the PDO, AMO, and NAO influence <span class="hlt">streamflow</span> variability in the United States. The warm phase of the PDO is associated with increased <span class="hlt">streamflow</span> in the central and southwest United States, while the warm phase of the AMO is associated with reduced <span class="hlt">streamflow</span> in these regions. The positive phase of the NAO and the cold phase of the AMO are associated with increased <span class="hlt">streamflow</span> in the central United States. Additionally, the coupled effects of the oceanic-atmospheric influences were evaluated on the basis of the long-term phase (cold/negative or warm/positive) of the interdecadal (PDO and AMO) and decadal (NAO) influences and ENSO. <span class="hlt">Streamflow</span> regions in the United States were identified that respond to these climatic couplings. The results show that the AMO may influence La Niña impacts in the Southeast, while the NAO may influence La Niña impacts in the Midwest. By utilizing the <span class="hlt">streamflow</span> water year and the long lead time for the oceanic-atmospheric variables, useful information can be provided to <span class="hlt">streamflow</span> forecasters and water managers.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.C44B..02W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.C44B..02W"><span>Spatial and Temporal Distribution of Water in Snow and Soil During Spring <span class="hlt">Snowmelt</span> in a Small Watershed in Northwest Colorado</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Webb, R.; Fassnacht, S. R.; Gooseff, M. N.</p> <p>2015-12-01</p> <p>The melting of a winter snowpack will often include spatially and temporally variable infiltration across the soil-snow-interface prior to generating <span class="hlt">streamflow</span>, groundwater recharge, or plant production. During spring <span class="hlt">snowmelt</span>, moisture distribution is largely driven by hydraulic gradients under variably saturated conditions within the soil and snowpack. In complex mountainous terrain, the variable melt rates across the landscape due to slope, aspect, and landcover add further irregularities to this dynamic system. The aim of this research is gain insight into the distribution of water both within and below a melting snowpack during spring at Dry Lake Study Site near Steamboat Springs, Colorado. This site is a small (0.2 km2) subalpine watershed with a seasonally persistent snowpack each year. Intensive field surveys were conducted to collect snow water equivalent and soil moisture distribution during April and May of 2014 and 2015. Results show the variability in soil moisture consistent with similar studies, suggesting soil moisture distribution follows a similar trend as accumulation of snow depth in relation to topographic and canopy influences. The soil moisture on south facing hillslopes tended to be less than north facing slopes, with flat terrain holding near saturated conditions, particularly in locations with thick layers of organic matter. However, of notable interest is the distribution of snow water equivalent during melt. Early in the melt period at the base of some hillslopes snow water equivalent increased as locations directly upslope decreased suggesting movement of moisture within the snowpack during the transitional period from winter to spring. The hydraulic conductivity of snow has been shown to be greater than that of common soils, suggesting that the timing of water movement from a snowpack to stream will be shortened when considering the flow through the snow layers compared to shallow groundwater on hillslopes. These results have</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003AGUFM.H11H..07S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003AGUFM.H11H..07S"><span><span class="hlt">Streamflow</span> Simulations of the Terrestrial Arctic Regime</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Su, F.; Adam, J.; Bowling, L.; Lettenmaier, D.</p> <p>2003-12-01</p> <p>Runoff from the Arctic terrestrial drainage system represents about two-thirds of the net flux of freshwater to the Arctic Ocean. Both the amount and the timing of freshwater inflow to the ocean systems are important to ocean circulation, salinity, and sea ice dynamics. In this study, the Variable Infiltration Capacity (VIC) model is used to simulate runoff and <span class="hlt">streamflow</span> from the pan-Arctic terrestrial domain from 1979 to 1999. The VIC model is a grid-based land surface scheme designed both for inclusion in GCMs, and for use as a stand-alone macroscale hydrological model. The key elements of the model that are particularly relevant to high latitude implementations include a two-layer energy balance snow model, a frozen soil/permafrost algorithm, a blowing snow model, and a lakes and wetlands model, none of which have previously been applied over the entire pan-Arctic domain. The model was applied over a 100kmx100km EASE grid mesh with full energy balance (closure for surface skin temperature) at a time step of 3 hours. A river network was developed for the model grid mesh and a routing scheme was run offline which takes daily VIC surface and subsurface runoff as input to obtain model simulated <span class="hlt">streamflows</span> at the outlets of selected study basins. The forcing data, soil, and vegetation parameters needed by the VIC are described and evaluated, along with calibration issues. The VIC <span class="hlt">streamflow</span> simulations for the Lena, Ob, and Mackenzie watersheds are compared with observations. For the 20-year study period, an estimate is provided of the mean freshwater flux to the Arctic and its spatial distribution, and is compared with previous estimates.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013HESS...17..817S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013HESS...17..817S"><span>Are <span class="hlt">streamflow</span> recession characteristics really characteristic?</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Stoelzle, M.; Stahl, K.; Weiler, M.</p> <p>2013-02-01</p> <p><span class="hlt">Streamflow</span> recession has been investigated by a variety of methods, often involving the fit of a model to empirical recession plots to parameterize a non-linear storage-outflow relationship based on the dQ/dt-Q method. Such recession analysis methods (RAMs) are used to estimate hydraulic conductivity, storage capacity, or aquifer thickness and to model <span class="hlt">streamflow</span> recession curves for regionalization and prediction at the catchment scale. Numerous RAMs have been published, but little is known about how comparably the resulting recession models distinguish characteristic catchment behavior. In this study we combined three established recession extraction methods with three different parameter-fitting methods to the power-law storage-outflow model to compare the range of recession characteristics that result from the application of these different RAMs. Resulting recession characteristics including recession time and corresponding storage depletion were evaluated for 20 meso-scale catchments in Germany. We found plausible ranges for model parameterization; however, calculated recession characteristics varied over two orders of magnitude. While recession characteristics of the 20 catchments derived with the different methods correlate strongly, particularly for the RAMs that use the same extraction method, not all rank the catchments consistently, and the differences among some of the methods are larger than among the catchments. To elucidate this variability we discuss the ambiguous roles of recession extraction procedures and the parameterization of the storage-outflow model and the limitations of the presented recession plots. The results suggest strong limitations to the comparability of recession characteristics derived with different methods, not only in the model parameters but also in the relative characterization of different catchments. A multiple-methods approach to investigating <span class="hlt">streamflow</span> recession characteristics should be considered for applications</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012HESSD...910563S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012HESSD...910563S"><span>Are <span class="hlt">streamflow</span> recession characteristics really characteristic?</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Stoelzle, M.; Stahl, K.; Weiler, M.</p> <p>2012-09-01</p> <p><span class="hlt">Streamflow</span> recession has been investigated by a variety of methods, often involving the fit of a model to empirical recession plots to parameterize a non-linear storage-outflow relationship. Such recession analysis methods (RAMs) are used to estimate hydraulic conductivity, storage capacity, or aquifer thickness and to model <span class="hlt">streamflow</span> recession curves for regionalization and prediction at the catchment scale. Numerous RAMs have been published, but little is known about how characteristic the resulting recession models are to distinguish characteristic catchment behavior. In this study we combined three established recession extraction methods with three different parameter-fitting methods to the power-law storage-outflow model to compare the range of recession characteristics that result from the application of these different RAMs. Resulting recession characteristics including recession time and corresponding storage depletion were evaluated for 20 meso-scale catchments in Germany. We found plausible ranges for model parameterization, however, calculated recession characteristics varied over two orders of magnitude. While recession characteristics of the 20 catchments derived with the different methods correlate strongly, particularly for the RAMs that use the same extraction method and while they rank the catchments relatively consistent, there are still considerable differences among the methods. To elucidate this variability we discuss the ambiguous roles of recession extraction procedures and the parameterization of storage-outflow model and the limitations of the presented recession plots. The results suggest strong limitations to the comparability of recession characteristics derived with different methods, not only in the model parameters but also in the relative characterization of different catchments. A multiple methods approach to investigate <span class="hlt">streamflow</span> recession characteristics should be considered for applications whenever possible.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.usgs.gov/twri/twri3-a13/','USGSPUBS'); return false;" href="https://pubs.usgs.gov/twri/twri3-a13/"><span>Computation of continuous records of <span class="hlt">streamflow</span></span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Kennedy, E.J.</p> <p>1983-01-01</p> <p>Records of continuous <span class="hlt">streamflow</span>, published in the U.S. Geological Survey annual Water Data Reports for the States and territories, are computed from field data, mainly discharge measurements and recorder charts or tapes. This manual describes the computation procedures used and some details of related field operations. It was compiled mostly from unpublished Water Resource Division district manuals edited and supplemented to emphasize digital-recorder and associated computer use. Methods used primarily for graphic-recorder gaging stations and non-recording gages are also included. Reference is made to other publications for some of the more specialized or unusually complex procedures.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.usgs.gov/fs/2012/3038/','USGSPUBS'); return false;" href="https://pubs.usgs.gov/fs/2012/3038/"><span>Calculating weighted estimates of peak <span class="hlt">streamflow</span> statistics</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Cohn, Timothy A.; Berenbrock, Charles; Kiang, Julie E.; Mason, Jr., Robert R.</p> <p>2012-01-01</p> <p>According to the Federal guidelines for flood-frequency estimation, the uncertainty of peak <span class="hlt">streamflow</span> statistics, such as the 1-percent annual exceedance probability (AEP) flow at a streamgage, can be reduced by combining the at-site estimate with the regional regression estimate to obtain a weighted estimate of the flow statistic. The procedure assumes the estimates are independent, which is reasonable in most practical situations. The purpose of this publication is to describe and make available a method for calculating a weighted estimate from the uncertainty or variance of the two independent estimates.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li class="active"><span>20</span></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_20 --> <div id="page_21" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li class="active"><span>21</span></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="401"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24552508','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24552508"><span>Unorganized machines for seasonal <span class="hlt">streamflow</span> series forecasting.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Siqueira, Hugo; Boccato, Levy; Attux, Romis; Lyra, Christiano</p> <p>2014-05-01</p> <p>Modern unorganized machines--extreme learning machines and echo state networks--provide an elegant balance between processing capability and mathematical simplicity, circumventing the difficulties associated with the conventional training approaches of feedforward/recurrent neural networks (FNNs/RNNs). This work performs a detailed investigation of the applicability of unorganized architectures to the problem of seasonal <span class="hlt">streamflow</span> series forecasting, considering scenarios associated with four Brazilian hydroelectric plants and four distinct prediction horizons. Experimental results indicate the pertinence of these models to the focused task.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.usgs.gov/ds/508/','USGSPUBS'); return false;" href="https://pubs.usgs.gov/ds/508/"><span><span class="hlt">Streamflow</span> Characteristics of Streams in Southeastern Afghanistan</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Vining, Kevin C.</p> <p>2010-01-01</p> <p>Statistical summaries of <span class="hlt">streamflow</span> data for all historical streamgaging stations that have available data in the southeastern Afghanistan provinces of Ghazni, Khost, Logar, Paktya, and Wardak, and a portion of Kabul Province are presented in this report. The summaries for each streamgaging station include a station desciption, table of statistics of monthly and annual mean discharges, table of monthly and annual flow duration, table of probability of occurrence of annual high discharges, table of probability of occurrence of annual low discharges, table of annual peak discharge and corresponding gage height for the period of record, and table of monthly and annual mean discharges for the period of record.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/12829774','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/12829774"><span><span class="hlt">Streamflow</span> and water well responses to earthquakes.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Montgomery, David R; Manga, Michael</p> <p>2003-06-27</p> <p>Earthquake-induced crustal deformation and ground shaking can alter stream flow and water levels in wells through consolidation of surficial deposits, fracturing of solid rocks, aquifer deformation, and the clearing of fracture-filling material. Although local conditions affect the type and amplitude of response, a compilation of reported observations of hydrological response to earthquakes indicates that the maximum distance to which changes in stream flow and water levels in wells have been reported is related to earthquake magnitude. Detectable <span class="hlt">streamflow</span> changes occur in areas within tens to hundreds of kilometers of the epicenter, whereas changes in groundwater levels in wells can occur hundreds to thousands of kilometers from earthquake epicenters.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.usgs.gov/fs/2015/3026/pdf/fs2015-3026.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/fs/2015/3026/pdf/fs2015-3026.pdf"><span><span class="hlt">Streamflow</span> of 2014: water year summary</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Jian, Xiaodong; Wolock, David M.; Jenter, Harry L.; Brady, Steve</p> <p>2015-01-01</p> <p>In the summary, reference is made to the term “runoff,” which is the depth to which a river basin or other geographic area, such as a State, would be covered with water if all the <span class="hlt">streamflow</span> within the area during a specified time period was uniformly distributed over the area. Runoff can also be used to quantify the magnitude of water flowing through rivers and streams in measurement units that can be compared from one area of the Nation to another.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70029572','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70029572"><span>Sources of nitrate in <span class="hlt">snowmelt</span> discharge: Evidence from water chemistry and stable isotopes of nitrate</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Piatek, K.B.; Mitchell, M.J.; Silva, S.R.; Kendall, C.</p> <p>2005-01-01</p> <p>To determine whether NO3- concentration pulses in surface water in early spring <span class="hlt">snowmelt</span> discharge are due to atmospheric NO 3-, we analyzed stream ??15N-NO 3- and ??18O-NO3- values between February and June of 2001 and 2002 and compared them to those of throughfall, bulk precipitation, snow, and groundwater. Stream total Al, DOC and Si concentrations were used to indicate preferential water flow through the forest floor, mineral soil, and ground water. The study was conducted in a 135-ha subcatchment of the Arbutus Watershed in the Huntington Wildlife Forest in the Adirondack Region of New York State, U.S.A. Stream discharge in 2001 increased from 0.6 before to 32.4 mm day-1 during <span class="hlt">snowmelt</span>, and element concentrations increased from 33 to 71 ??mol L-1 for NO3-, 3 to 9 ??mol L-1 for total Al, and 330 to 570 ??mol L-1 for DOC. Discharge in 2002 was variable, with a maximum of 30 mm day-1 during <span class="hlt">snowmelt</span>. The highest NO3-, Al, and DOC concentrations were 52, 10, and 630 ??mol L -1, respectively, and dissolved Si decreased from 148 ??mol L -1 before to 96 ??mol L-1 during <span class="hlt">snowmelt</span>. Values of ??15N and ??18O of NO3- in stream water were similar in both years. Stream water, atmospherically- derived solutions, and groundwaters had overlapping ??15N- NO3- values. In stream and ground water, ??18O-NO3- values ranged from +5.9 to +12.9??? and were significantly lower than the +58.3 to +78.7??? values in atmospheric solutions. Values of ??18O-NO3- indicating nitrification, increase in Al and DOC, and decrease in dissolved Si concentrations indicating water flow through the soil suggested a dilution of groundwater NO3- by increasing contributions of forest floor and mineral soil NO3- during <span class="hlt">snowmelt</span>. ?? Springer 2005.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AGUFM.C13C..01L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AGUFM.C13C..01L"><span>Importance of <span class="hlt">snowmelt</span>-derived fluxes on the groundwater flow in a high elevation meadow (Invited)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lowry, C.; Loheide, S. P.; Deems, J. S.; Moore, C. E.; Lundquist, J. D.</p> <p>2010-12-01</p> <p>In order to manage or restore riparian ecosystems in high elevation environments, under both current and future climatic conditions, we must have an understanding of both stream flow and groundwater dynamics. Seasonal changes in both stream flow and water table fluctuations in these environments are dependent on <span class="hlt">snowmelt</span>-derived flux entering riparian zones from the larger watershed. Without reliable data, from field observations or numerical modeling, there is little chance of accurately quantifying changes in water table dynamics, surface inundation, soil moisture or stream stage, which are critical to riparian vegetation within these systems. In the work presented here, we show the impact of <span class="hlt">snowmelt</span>-derived groundwater flux from the surrounding hillslopes on water table dynamics in Tuolumne Meadows, which is located in the Sierra Nevada Mountains of California, USA. Results show the importance of a combination of fluxes at the hillslope boundaries, <span class="hlt">snowmelt</span> within the meadow and changes in the stream stage on water levels within the meadow. These results also demonstrate the importance of timing of groundwater flux entering the meadow as a result of spring <span class="hlt">snowmelt</span>, which was observed to vary over 20 days based on the location, aspect, and local geology of the contributing area within the larger watershed. Identifying temporal and spatial variability in flux entering the meadow is necessary in order to simulate changes in water levels within the meadow. Caution must be taken when linking watershed scale models to local meadow scale models as results can vary significantly based on the temporal and spatial scales at which boundary fluxes are lumped. Without a clear hydrologic representation of <span class="hlt">snowmelt</span> on the surrounding hillslopes, it is difficult to simulate groundwater dynamics within these riparian ecosystems with the accuracy necessary for understanding ecosystem response.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFM.H53G1786F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFM.H53G1786F"><span>Modelling of <span class="hlt">snowmelt</span> infiltration in heterogeneous seasonally-frozen soil monitored by electrical resistivity measurements</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>French, H. K.; Binley, A. M.; Voss, C.</p> <p>2016-12-01</p> <p>Infiltration during <span class="hlt">snowmelt</span> can be highly heterogeneous due to the formation of ice on the ground surface below the snow cover. In situations where snow is contaminated, such as along highways and airports due to de-icing agents, it is important to predict the zone of infiltration, because this will determine the retention time and potential for degradation in the unsaturated zone. In 2001, infiltration during <span class="hlt">snowmelt</span> was monitored over a small area (4m2) using time-lapse electrical resistivity monitoring at Gardermoen, Norway. Data revealed a spatio-temporal variable infiltration pattern related to micro topography of the ground surface (French and Binley, 2004). In this study, we want to test the suitability of a newly developed numerical model for water and heat transport including phase change in a variably saturated soil against field observations. Monitored weather and snow data defined the boundary conditions of a simulated unsaturated profile with seasonal freezing. The dependency of capillary pressure and permeability on water saturation is taken from van Genuchten equation with the addition of a scaling parameter, to account for the heterogeneity of the hydraulic permeability. Soil physical data and heterogeneity (variance and correlation structure of the permeability) was based on local soil measurements. The available amount of meltwater for infiltration over the area was based on average <span class="hlt">snowmelt</span> measurements at the site. Different infiltration scenarios were tested. Soil temperatures, TDR measurements of soil moisture, a tracer experiment conducted at an adjacent site and changes in electrical resistivity were used to validate the model of infiltration and thawing. The model was successful in reproducing the thawing and soil moisture patterns observed in the soil, and hence looks like a promising tool for predicting <span class="hlt">snowmelt</span> infiltration and melting of ground frost in a sandy unsaturated soil. ReferencesFrench, H.K. and Binley, A. (2004) <span class="hlt">Snowmelt</span></p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..18.7692A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..18.7692A"><span>Timing and regional patterns of <span class="hlt">snowmelt</span> on Antarctic sea ice from passive microwave satellite observations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Arndt, Stefanie; Willmes, Sascha; Dierking, Wolfgang; Nicolaus, Marcel</p> <p>2016-04-01</p> <p>The better understanding of temporal variability and regional distribution of surface melt on Antarctic sea ice is crucial for the understanding of atmosphere-ocean interactions and the determination of mass and energy budgets of sea ice. Since large regions of Antarctic sea ice are covered with snow during most of the year, observed inter-annual and regional variations of surface melt mainly represents melt processes in the snow. It is therefore important to understand the mechanisms that drive <span class="hlt">snowmelt</span>, both at different times of the year and in different regions around Antarctica. In this study we combine two approaches for observing both surface and volume <span class="hlt">snowmelt</span> by means of passive microwave satellite data. The former is achieved by measuring diurnal differences of the brightness temperature TB at 37 GHz, the latter by analyzing the ratio TB(19GHz)/TB(37GHz). Moreover, we use both melt onset proxies to divide the Antarctic sea ice cover into characteristic surface melt patterns from 1988/89 to 2014/15. Our results indicate four characteristic melt types. On average, 43% of the ice-covered ocean shows diurnal freeze-thaw cycles in the surface snow layer, resulting in temporary melt (Type A), less than 1% shows continuous <span class="hlt">snowmelt</span> throughout the snowpack, resulting in strong melt over a period of several days (Type B), 19% shows Type A and B taking place consecutively (Type C), and for 37% no melt is observed at all (Type D). Continuous melt is primarily observed in the outflow of the Weddell Gyre and in the northern Ross Sea, usually 20 days after the onset of temporary melt. Considering the entire data set, <span class="hlt">snowmelt</span> processes and onset do not show significant temporal trends. Instead, areas of increasing (decreasing) sea-ice extent have longer (shorter) periods of continuous <span class="hlt">snowmelt</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/10103104','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/10103104"><span>Adjusted <span class="hlt">Streamflow</span> and Storage 1928-1989 : with Listings of Historical <span class="hlt">Streamflow</span>, Summation of Storage Change and Adjusted <span class="hlt">Streamflow</span> : Columbia River and Coastal Basins.</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>A.G. Crook Company</p> <p>1993-04-01</p> <p>The development of irrigation projects since the 1830's and the construction of major dams and reservoirs since the early 1900's have altered substantially the natural <span class="hlt">streamflow</span> regimen of the Columbia River and its tributaries. As development expanded a multipurpose approach to <span class="hlt">streamflow</span> regulation evolved to provide flood control, irrigation, hydropower generation, navigation, recreation, water quality enhancement, fish and wildlife, and instream flow maintenance. The responsible agencies use computer programs to determine the effects of various alternative system regulations. This report describes the development of the <span class="hlt">streamflow</span> data that these computer programs use.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.fs.usda.gov/treesearch/pubs/13117','TREESEARCH'); return false;" href="https://www.fs.usda.gov/treesearch/pubs/13117"><span>A time-corrector device for adjusting <span class="hlt">streamflow</span> records</span></a></p> <p><a target="_blank" href="http://www.fs.usda.gov/treesearch/">Treesearch</a></p> <p>Raymond W. Lavigne</p> <p>1960-01-01</p> <p>The first job in compiling <span class="hlt">streamflow</span> data from <span class="hlt">streamflow</span> charts is to mark storm rises and storm peaks, make corrections as necessary for time and stage height, and account for irregularities on the chart. Errors in the time scale can result from faulty clock operation, irregularities in chart take-up by the drum, or expansion of the paper. This note suggests a...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.usgs.gov/of/1984/0704/report.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/of/1984/0704/report.pdf"><span><span class="hlt">Streamflow</span> and basin characteristics at selected sites in Kentucky</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Melcher, N.B.; Ruhl, K.J.</p> <p>1984-01-01</p> <p>Common basin and <span class="hlt">streamflow</span> characteristics for sites in Kentucky are presented. Basin characteristics include quantified drainage basin parameters and statistics on areal rainfall. <span class="hlt">Streamflow</span> characteristics include tables for mean, high and low flow frequencies and partial duration discharge. The data listed in this report are for continuous and low-flow partial-record sites. (USGS)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.fs.usda.gov/treesearch/pubs/33091','TREESEARCH'); return false;" href="https://www.fs.usda.gov/treesearch/pubs/33091"><span>Exploring <span class="hlt">streamflow</span> response to effective rainfall across event magnitude scale</span></a></p> <p><a target="_blank" href="http://www.fs.usda.gov/treesearch/">Treesearch</a></p> <p>Teemu Kokkonen; Harri Koivusalo; Tuomo Karvonen; Barry Croke; Anthony Jakeman</p> <p>2004-01-01</p> <p>Sets of flow events from four catchments were selected to study how dynamics in the conversion of effective rainfall into <span class="hlt">streamflow</span> depends on the event size. The approach taken was to optimize parameters of a linear delay function and effective rainfall series concurrently from precipitation <span class="hlt">streamflow</span> data without imposing a functional form of the precipitation...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=155339&keyword=annual+AND+report+AND+analysis&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50&CFID=90674053&CFTOKEN=73063787','EPA-EIMS'); return false;" href="http://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=155339&keyword=annual+AND+report+AND+analysis&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50&CFID=90674053&CFTOKEN=73063787"><span>ECOLOGICALLY-RELEVANT QUANTIFICATION OF <span class="hlt">STREAMFLOW</span> REGIMES IN WESTERN STREAMS</span></a></p> <p><a target="_blank" href="http://oaspub.epa.gov/eims/query.page">EPA Science Inventory</a></p> <p></p> <p></p> <p>This report describes the rationale for and application of a protocol for estimation of ecologically-relevant <span class="hlt">streamflow</span> metrics that quantify <span class="hlt">streamflow</span> regime for ungaged sites subject to a range of human impact. The analysis presented here is focused on sites sampled by the U....</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.fs.usda.gov/treesearch/pubs/52749','TREESEARCH'); return false;" href="https://www.fs.usda.gov/treesearch/pubs/52749"><span><span class="hlt">Streamflow</span> response to increasing precipitation extremes altered by forest management</span></a></p> <p><a target="_blank" href="http://www.fs.usda.gov/treesearch/">Treesearch</a></p> <p>Charlene N. Kelly; Kevin J. McGuire; Chelcy Ford Miniat; James M. Vose</p> <p>2016-01-01</p> <p>Increases in extreme precipitation events of floods and droughts are expected to occur worldwide. The increase in extreme events will result in changes in <span class="hlt">streamflow</span> that are expected to affect water availability for human consumption and aquatic ecosystem function. We present an analysis that may greatly improve current <span class="hlt">streamflow</span> models by quantifying the...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFMGC33C1264T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFMGC33C1264T"><span>The impact of urbanization and climate change on <span class="hlt">streamflow</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tchalim, G.; Armal, S.</p> <p>2016-12-01</p> <p><span class="hlt">Streamflow</span> or the surface runoff is the flow of water that occurs when excess water from rain, melt-water, or other sources flows over the earth's surface. The <span class="hlt">streamflow</span> can be affected by different aspects. In this project we are focusing on how land cover change (urbanization) and Climate Change can affect the watershed response on <span class="hlt">streamflow</span>. we focus our research on Walnut Creek-Neuse River watershed in North Carolina. The required data is found from a range of databases, including USGS stream flow, NCDC hourly precipitation, National Land Cover Database(NLCD) and National Hydrography Database. In the side of urbanization, we compare the land cover of the region over two decades and evaluate the statistics parameters in the <span class="hlt">streamflow</span> from the USGS monitoring point. In the side of climate change we study the ratio of <span class="hlt">streamflow</span> to rainfall in the region.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.usgs.gov/fs/2014/3030/pdf/fs2014-3030.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/fs/2014/3030/pdf/fs2014-3030.pdf"><span><span class="hlt">Streamflow</span> of 2013: water year summary</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Jian, Xiaodong; Wolock, David M.; Lins, Harry F.; Brady, Steve</p> <p>2014-01-01</p> <p>The maps and graphs in this summary describe <span class="hlt">streamflow</span> conditions for water year 2013 (October 1, 2012, to September 30, 2013) in the context of the 84-year period from 1930 through 2013, unless otherwise noted. The illustrations are based on observed data from the U.S. Geological Survey’s (USGS) National Water Information System ( http://waterdata.usgs.gov/nwis/). The period 1930–2013 was used because, prior to 1930, the number of streamgages was too small to provide representative data for computing statistics for most regions of the country. In the summary, reference is made to the term “runoff,” which is the depth to which a river basin, State, or other geographic area would be covered with water if all the <span class="hlt">streamflow</span> within the area during a specified time period was uniformly distributed upon it. Runoff quantifies the magnitude of water flowing through the Nation’s rivers and streams in measurement units that can be compared from one area to another.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/17503203','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/17503203"><span>Assessment of river water quality during <span class="hlt">snowmelt</span> and base flow periods in two catchment areas with different land use.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Woli, Krishna Prasad; Hayakawa, Atsushi; Kuramochi, Kanta; Hatano, Ryusuke</p> <p>2008-02-01</p> <p>River water quality was evaluated with respect to eutrophication and land use during spring <span class="hlt">snowmelt</span> and summer base flow periods in Abashiri (mixed cropland-livestock farming) and Okoppe (grassland-based dairy cattle farming), eastern Hokkaido, Japan. Water from rivers and tributaries was sampled during <span class="hlt">snowmelt</span> and summer base flow periods in 2005, and river flow was measured. Total N (TN), NO(3)-N, and Si concentrations were determined using standard methods. Total catchment and upland areas for each sampling site were determined with ArcGIS hydrology modeling software and 1:25,000-scale digital topographic maps. Specific discharge was significantly higher during <span class="hlt">snowmelt</span> than during base flow. In both areas, TN concentrations increased, whereas Si concentrations decreased, with increased specific discharge, and were significantly higher during <span class="hlt">snowmelt</span>. The Si:TN mole ratio decreased to below or close to the threshold value for eutrophication (2.7) in one-third of sites during <span class="hlt">snowmelt</span>. River NO(3)-N concentrations during base flow were significantly and positively correlated with the proportion of upland fields in the catchment in both the Abashiri (r = 0.88, P < 0.001) and Okoppe (r = 0.43, P < 0.01) areas. However, the regression slope, defined as the impact factor (IF) of water quality, was much higher in Abashiri (0.025) than in Okoppe (0.0094). The correlations were also significantly positive during <span class="hlt">snowmelt</span> in both areas, but IF was four to eight times higher during <span class="hlt">snowmelt</span> than during base flow. Higher discharge of N from upland fields and grasslands during <span class="hlt">snowmelt</span> and the resulting eutrophication in estuaries suggest that nutrient discharge during <span class="hlt">snowmelt</span> should be taken into account when assessing and monitoring the annual loss of nutrients from agricultural fields.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFM.H13L1583S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFM.H13L1583S"><span>Changes in <span class="hlt">streamflow</span> extremes in the Colorado River Basin and implications for the water-energy nexus</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Solander, K.; Bennett, K. E.; Middleton, R. S.</p> <p>2016-12-01</p> <p>The global phenomenon of climate change-induced shifts in precipitation leading to "wet regions getting wetter" and "dry regions getting drier" has been widely studied. However, the propagation of the changes in atmospheric moisture conditions to the ground within stream channels is not a direct relationship due to a combination of temporal differences in these moisture shifts and how water interacts with various land surfaces. Precipitation and <span class="hlt">streamflow</span> changes in the Colorado River Basin (CRB) are of particular interest due to its rapidly growing population, projected temperature increases that are expected to be higher than elsewhere in the contiguous United States, and subsequent climate-driven disturbances including drought, vegetation mortality, and wildfire, thereby making the region more vulnerable to shifts in hydrologic extremes. Here, we attempt to determine how <span class="hlt">streamflow</span> extremes have changed in the CRB by using the Generalized Extreme Value (GEV) and Mann-Kendall trend analysis on historical observations and future simulations. We specifically evaluate these changes in the context of key high- and low-flow metrics including the maximum, 95th percentile, 5th percentile, minimum, center timing, and 7Q10 maximum and minimum flows using daily data at the monthly, seasonal, and annual timescales. By evaluating how the center timing and other <span class="hlt">streamflow</span> statistics are changing at different elevations, this study also assesses the relative influence of changes in <span class="hlt">snowmelt</span> versus overall precipitation on the associated shifts in extremes. Historical <span class="hlt">streamflow</span> records were obtained from the United States Geological Survey (USGS) GAGES II dataset, while future records were derived using downscaled simulations from IPCC's CMIP5 Global Climate Model (GCM) database. Although preliminary results of the future simulations suggest that climate change will cause 7Q10 low flows to increase by 7% over the long-term, the combined impacts of climate and vegetation</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009AGUFM.H23I..05S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009AGUFM.H23I..05S"><span>Combining a Water Balance Model for <span class="hlt">Streamflow</span> Simulations with Long Tree-Ring Records to Improve Estimation of Water Resource Variability</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Saito, L.; Biondi, F.; Salas, J.; Strachan, S.</p> <p>2009-12-01</p> <p>A widely used approach for extending the relatively brief instrumental record of <span class="hlt">streamflow</span> and obtaining a paleo perspective on recent hydrological changes is by means of tree-ring records. To date, dendrohydrologists have employed sophisticated regression techniques to extend runoff records, but this empirical approach cannot directly test the influence of watershed factors that alter <span class="hlt">streamflow</span> independently of climate. We designed a mechanistic watershed model to calculate <span class="hlt">streamflows</span> at annual time steps using as few inputs as possible. The model was calibrated and verified for the upper reaches of the Walker River, which straddles the boundary between the Sierra Nevada of California and the Great Basin of Nevada. Even though the model incorporated simplified relationships between precipitation and other components of the hydrologic cycle, it predicted water year <span class="hlt">streamflows</span> with correlations of 0.9 when appropriate precipitation values were used. An expansion of this model for seasonal time steps has been completed through the addition of a <span class="hlt">snowmelt</span> component. Ongoing work involves using the model to generate <span class="hlt">streamflows</span> from a 2300-year annual proxy record of precipitation developed using western juniper (Juniperus occidentalis) tree-ring records from the Walker River basin. The main climate signal in the tree-ring chronology is October through September (i.e., water year) precipitation, and this record has already been analyzed with respect to duration, magnitude, and peak of extended dry and wet episodes, including the 1930s drought and the early 1900s pluvial. According to this numerical classification scheme, the most remarkable episode was the mid-1800s drought (1840-'51), followed by two pluvials, at the end of the 7th century (682-692) and at the beginning of the 20th one (1900-'19); the Dust Bowl drought (1927-'36 in this record) was in 73rd position. Therefore, statistics derived from the instrumental record appear to be skewed by a truly unique wet</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..1917995D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..1917995D"><span>Forecasting <span class="hlt">snowmelt</span> flooding over Britain using the Grid-to-Grid model: a review and assessment of methods</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dey, Seonaid R. A.; Moore, Robert J.; Cole, Steven J.; Wells, Steven C.</p> <p>2017-04-01</p> <p>In many regions of high annual snowfall, <span class="hlt">snowmelt</span> modelling can prove to be a vital component of operational flood forecasting and warning systems. Although Britain as a whole does not experience prolonged periods of lying snow, with the exception of the Scottish Highlands, the inclusion of <span class="hlt">snowmelt</span> modelling can still have a significant impact on the skill of flood forecasts. Countrywide operational flood forecasts over Britain are produced using the national Grid-to-Grid (G2G) distributed hydrological model. For Scotland, <span class="hlt">snowmelt</span> is included in these forecasts through a G2G snow hydrology module involving temperature-based snowfall/rainfall partitioning and functions for temperature-excess <span class="hlt">snowmelt</span>, snowpack storage and drainage. Over England and Wales, the contribution of <span class="hlt">snowmelt</span> is included by pre-processing the precipitation prior to input into G2G. This removes snowfall diagnosed from weather model outputs and adds <span class="hlt">snowmelt</span> from an energy budget land surface scheme to form an effective liquid water gridded input to G2G. To review the operational options for including <span class="hlt">snowmelt</span> modelling in G2G over Britain, a project was commissioned by the Environment Agency through the Flood Forecasting Centre (FFC) for England and Wales and in partnership with the Scottish Environment Protection Agency (SEPA) and Natural Resources Wales (NRW). Results obtained from this <span class="hlt">snowmelt</span> review project will be reported on here. The operational methods used by the FFC and SEPA are compared on past <span class="hlt">snowmelt</span> floods, alongside new alternative methods of treating <span class="hlt">snowmelt</span>. Both case study and longer-term analyses are considered, covering periods selected from the winters 2009-2010, 2012-2013, 2013-2014 and 2014-2015. Over Scotland, both of the <span class="hlt">snowmelt</span> methods used operationally by FFC and SEPA provided a clear improvement to the river flow simulations. Over England and Wales, fewer and less significant snowfall events occurred, leading to less distinction in the results between the</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li class="active"><span>21</span></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_21 --> <div id="page_22" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li class="active"><span>22</span></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="421"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.usgs.gov/wri/wri96-4001/','USGSPUBS'); return false;" href="https://pubs.usgs.gov/wri/wri96-4001/"><span>Evaluation of the <span class="hlt">streamflow</span>-gaging network of Alaska in providing regional <span class="hlt">streamflow</span> information</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Brabets, Timothy P.</p> <p>1996-01-01</p> <p>In 1906, the U.S. Geological Survey (USGS) began operating a network of <span class="hlt">streamflow</span>-gaging stations in Alaska. The primary purpose of the <span class="hlt">streamflow</span>- gaging network has been to provide peak flow, average flow, and low-flow characteristics to a variety of users. In 1993, the USGS began a study to evaluate the current network of 78 stations. The objectives of this study were to determine the adequacy of the existing network in predicting selected regional flow characteristics and to determine if providing additional <span class="hlt">streamflow</span>-gaging stations could improve the network's ability to predict these characteristics. Alaska was divided into six distinct hydrologic regions: Arctic, Northwest, Southcentral, Southeast, Southwest, and Yukon. For each region, historical and current <span class="hlt">streamflow</span> data were compiled. In Arctic, Northwest, and Southwest Alaska, insufficient data were available to develop regional regression equations. In these areas, proposed locations of <span class="hlt">streamflow</span>-gaging stations were selected by using clustering techniques to define similar areas within a region and by spatial visual analysis using the precipitation, physiographic, and hydrologic unit maps of Alaska. Sufficient data existed in Southcentral and Southeast Alaska to use generalized least squares (GLS) procedures to develop regional regression equations to estimate the 50-year peak flow, annual average flow, and a low-flow statistic. GLS procedures were also used for Yukon Alaska but the results should be used with caution because the data do not have an adequate spatial distribution. Network analysis procedures were used for the Southcentral, Southeast, and Yukon regions. Network analysis indicates the reduction in the sampling error of the regional regression equation that can be obtained given different scenarios. For Alaska, a 10-year planning period was used. One scenario showed the results of continuing the current network with no additional gaging stations and another scenario showed the results</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JHyd..539..125G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JHyd..539..125G"><span>Indicator bacteria and associated water quality constituents in stormwater and <span class="hlt">snowmelt</span> from four urban catchments</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Galfi, H.; Österlund, H.; Marsalek, J.; Viklander, M.</p> <p>2016-08-01</p> <p>Four indicator bacteria were measured in association with physico-chemical constituents and selected inorganics during rainfall, baseflow and <span class="hlt">snowmelt</span> periods in storm sewers of four urban catchments in a northern Swedish city. The variation patterns of coliforms, Escherichia coli, enterococci and Clostridium perfringens concentrations were assessed in manually collected grab samples together with those of phosphorus, nitrogen, solids, and readings of pH, turbidity, water conductivity, temperature and flow rates to examine whether these constituents could serve as potential indicators of bacteria sources. A similar analysis was applied to variation patterns of eight selected inorganics typical for baseflow and stormwater runoff to test the feasibility of using these inorganics to distinguish between natural and anthropogenic sources of inflow into storm sewers. The monitored catchments varied in size, the degree of development, and land use. Catchment and season (i.e., rainy or <span class="hlt">snowmelt</span> periods) specific variations were investigated for sets of individual stormwater samples by the principal component analysis (PCA) to identify the constituents with variation patterns similar to those of indicator bacteria, and to exclude the constituents with less similarity. In the reduced data set, the similarities were quantified by the clustering correlation analysis. Finally, the positive/negative relationships found between indicator bacteria and the identified associated constituent groups were described by multilinear regressions. In the order of decreasing concentrations, coliforms, E. coli and enterococci were found in the highest mean concentrations during both rainfall and <span class="hlt">snowmelt</span> generated runoff. Compared to dry weather baseflow, concentrations of these three indicators in stormwater were 10 (<span class="hlt">snowmelt</span> runoff) to 102 (rain runoff) times higher. C. perfringens mean concentrations were practically constant regardless of the season and catchment. The type and number of</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.usgs.gov/of/2014/1128/pdf/ofr2014-1128.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/of/2014/1128/pdf/ofr2014-1128.pdf"><span>Comparison of historical <span class="hlt">streamflows</span> to 2013 <span class="hlt">Streamflows</span> in the Williamson, Sprague, and Wood Rivers, Upper Klamath Lake Basin, Oregon</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Hess, Glen W.; Stonewall, Adam J.</p> <p>2014-01-01</p> <p>In 2013, the Upper Klamath Lake Basin, Oregon, experienced a dry spring, resulting in an executive order declaring a state of drought emergency in Klamath County. The 2013 drought limited the water supply and led to a near-total cessation of surface-water diversions for irrigation above Upper Klamath Lake once regulation was implemented. These conditions presented a unique opportunity to understand the effects of water right regulation on <span class="hlt">streamflows</span>. The effects of regulation of diversions were evaluated by comparing measured 2013 <span class="hlt">streamflow</span> with data from hydrologically similar years. Years with spring <span class="hlt">streamflow</span> similar to that in 2013 measured at the Sprague River gage at Chiloquin from water years 1973 to 2012 were used to define a Composite Index Year (CIY; with diversions) for comparison to measured 2013 <span class="hlt">streamflows</span> (no diversions). The best-fit 6 years (1977, 1981, 1990, 1991, 1994, and 2001) were used to determine the CIY. Two streams account for most of the <span class="hlt">streamflow</span> into Upper Klamath Lake: the Williamson and Wood Rivers. Most <span class="hlt">streamflow</span> into the lake is from the Williamson River Basin, which includes the Sprague River. Because most of the diversion regulation affecting the <span class="hlt">streamflow</span> of the Williamson River occurred in the Sprague River Basin, and because of uncertainties about historical flows in a major diversion above the Williamson River gage, <span class="hlt">streamflow</span> data from the Sprague River were used to estimate the change in <span class="hlt">streamflow</span> from regulation of diversions for the Williamson River Basin. Changes in <span class="hlt">streamflow</span> outside of the Sprague River Basin were likely minor relative to total <span class="hlt">streamflow</span>. The effect of diversion regulation was evaluated using the “Baseflow Method,” which compared 2013 baseflow to baseflow of the CIY. The Baseflow Method reduces the potential effects of summer precipitation events on the calculations. A similar method using <span class="hlt">streamflow</span> produced similar results, however, despite at least one summer precipitation event. The</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010HESS...14.1639T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010HESS...14.1639T"><span>A past discharge assimilation system for ensemble <span class="hlt">streamflow</span> forecasts over France - Part 2: Impact on the ensemble <span class="hlt">streamflow</span> forecasts</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Thirel, G.; Martin, E.; Mahfouf, J.-F.; Massart, S.; Ricci, S.; Regimbeau, F.; Habets, F.</p> <p>2010-08-01</p> <p>The use of ensemble <span class="hlt">streamflow</span> forecasts is developing in the international flood forecasting services. Ensemble <span class="hlt">streamflow</span> forecast systems can provide more accurate forecasts and useful information about the uncertainty of the forecasts, thus improving the assessment of risks. Nevertheless, these systems, like all hydrological forecasts, suffer from errors on initialization or on meteorological data, which lead to hydrological prediction errors. This article, which is the second part of a 2-part article, concerns the impacts of initial states, improved by a <span class="hlt">streamflow</span> assimilation system, on an ensemble <span class="hlt">streamflow</span> prediction system over France. An assimilation system was implemented to improve the <span class="hlt">streamflow</span> analysis of the SAFRAN-ISBA-MODCOU (SIM) hydro-meteorological suite, which initializes the ensemble <span class="hlt">streamflow</span> forecasts at Météo-France. This assimilation system, using the Best Linear Unbiased Estimator (BLUE) and modifying the initial soil moisture states, showed an improvement of the <span class="hlt">streamflow</span> analysis with low soil moisture increments. The final states of this suite were used to initialize the ensemble <span class="hlt">streamflow</span> forecasts of Météo-France, which are based on the SIM model and use the European Centre for Medium-range Weather Forecasts (ECMWF) 10-day Ensemble Prediction System (EPS). Two different configurations of the assimilation system were used in this study: the first with the classical SIM model and the second using improved soil physics in ISBA. The effects of the assimilation system on the ensemble <span class="hlt">streamflow</span> forecasts were assessed for these two configurations, and a comparison was made with the original (i.e. without data assimilation and without the improved physics) ensemble <span class="hlt">streamflow</span> forecasts. It is shown that the assimilation system improved most of the statistical scores usually computed for the validation of ensemble predictions (RMSE, Brier Skill Score and its decomposition, Ranked Probability Skill Score, False Alarm Rate, etc</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.usgs.gov/sir/2005/5118/','USGSPUBS'); return false;" href="https://pubs.usgs.gov/sir/2005/5118/"><span><span class="hlt">Streamflow</span> and water-quality trends of the Rio Chama and Rio Grande, northern and central New Mexico, water years 1985 to 2002</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Langman, Jeff B.; Nolan, Emma O.</p> <p>2005-01-01</p> <p>The City of Albuquerque plans to divert San Juan-Chama Project water from the Rio Grande for potable water use. This report examines <span class="hlt">streamflow</span> and water-quality trends in the Rio Chama and the Rio Grande for water years 1985 to 2002 following the implementation of reservoir storage agreements in northern and central New Mexico. <span class="hlt">Streamflow</span>/water-quality stations used for this study include the Rio Grande stations of Taos, Otowi, San Felipe, and Albuquerque and the Rio Chama station of Chamita. Water years 1985 to 2002 were a period of larger than average precipitation and <span class="hlt">streamflow</span> compared to the stations. historical averages. Annual precipitation and <span class="hlt">streamflow</span> trended downward during the study period because of a drought during 1999 to 2002. <span class="hlt">Streamflow</span> in the Rio Chama and Rio Grande was divided into three distinct seasonal periods that corresponded to natural and anthropogenic influences: fall/winter baseflow (November through February), <span class="hlt">snowmelt</span> runoff (March through June), and the irrigation/monsoon (July through October) seasons. A calcium bicarbonate water type was evident at all study area stations on the Rio Chama and Rio Grande. Specific conductance increased downstream, but alkalinity and pH did not substantially change in the downstream direction. Nearly all nitrogen and phosphorous concentrations were less than 1 milligram per liter for all stations. Median trace-element concentrations and maximum radionuclide concentrations did not exceed drinking-water standards. Anthropogenic compounds were infrequently detected in the Rio Chama and Rio Grande, and concentrations did not exceed drinking-water standards. Water quality in the Rio Chama and Rio Grande varied spatially and temporally during water years 1985 to 2002. Specific conductance increased downstream in the Rio Grande during the fall/winter baseflow and <span class="hlt">snowmelt</span> runoff seasons but was similar at the Taos, Otowi, and San Felipe stations during the irrigation/monsoon season. This similarity was a</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.usgs.gov/unnumbered/70047882/report.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/unnumbered/70047882/report.pdf"><span>Statistical summaries of New Jersey <span class="hlt">streamflow</span> records</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Laskowski, Stanley L.</p> <p>1970-01-01</p> <p>In 1961 the U.S. Geological Survey prepared a report which was published by the State of New Jersey as Water Resources Circular 6, "New Jersey <span class="hlt">Streamflow</span> Records analyzed with Electronic Computer" by Miller and McCall. Basic discharge data for periods of record through 1958 were analyzed for 59 stream-gaging stations in New Jersey and flow-duration, low-flow, and high-flow tables were presented. The purpose of the current report is to update and expand Circular 6 by presenting, with a few meaningful statistics and tables, the bulk of the information that may be obtained from the mass of <span class="hlt">streamflow</span> records available. The records for 79 of approximately 110 stream-gaging stations presently or previously operated in New Jersey, plus records for three stations in Pennsylvania, and one in New York are presented in summarized form. In addition to inclusing a great number of stations in this report, more years of record and more tables are listed for each station. A description of the station, three arrangements of data summarizing the daily flow records and one table listing statistics of the monthly mean flows are provided. No data representing instantaneous extreme flows are given. Plotting positions for the three types of curves describing the characteristics of daily discharge are listed for each station. Statistical parameters are also presented so that alternate curves may be drawn. All stations included in this report have 5 or more years of record. The data presented herein are based on observed flow past the gaging station. For any station where the observed flow is affected by regulation or diversion, a "Remarks" paragraph, explaining the possible effect on the data, is included in the station description. Since any <span class="hlt">streamflow</span> record is a sample in time, the data derived from these records can provide only a guide to expected future flows. For this reason the flow records are analyzed by statistical techniques, and the magnitude of sampling errors should be</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014EGUGA..16..574P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014EGUGA..16..574P"><span>Shift of extreme spring <span class="hlt">streamflow</span> on the Belorussian rivers and its association with changes of cyclonic activity over Eastern Europe</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Partasenok, Irina; Chekan, Gregory</p> <p>2014-05-01</p> <p>The intra-annual distribution of precipitation is the most variable component of the water resources of Belarus. This distribution is controlled by extratropical cyclones from the Atlantic Ocean and Mediterranean that bring most of precipitation to the nation. That's why the aim of our study was to quantify major characteristics of these cyclones and to estimate effects of their passing through the Belorussian territory on regional water budget including floods and low water conditions. We documented the long-term fluctuations of <span class="hlt">streamflow</span> and occurrence of extreme phenomena on the rivers of Belarus during the post-World War II period. It was established that annual water budget of the nation vary from year to year without systematic tendencies. At the same time, analysis of intra-annual distribution of <span class="hlt">streamflow</span> reveals significant changes since the 1970s: increase of winter and decrease of spring runoff. As a result, the frequency of extreme spring floods has decreased. These changes in water regime are associated with climatic anomalies caused by large-scale alterations in atmospheric circulation, specifically in trajectories of cyclones. As a manifestation of these circulation changes, we observe increase of the surface air temperatures, more frequent cold season thaws, redistribution of seasonal precipitation totals, and decrease of the fraction of frozen precipitation in the shoulder seasons. Analysis of cyclonic activity over Belarus during the past 60 years in the cold season (December through February) shows the largest number of cyclones in 1950-1970. During this period, the largest number of spring floods caused by <span class="hlt">snowmelt</span> on the rivers of Belarus was reported. Since 1970, we observe a decrease in the total number of cyclones but also an increasing strength (deepening) of the remaining cyclones in the cold season. That has led to some precipitation increase. During the last four decades, more frequent zonal air movement in the atmosphere and</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.usgs.gov/fs/2005/3017/','USGSPUBS'); return false;" href="https://pubs.usgs.gov/fs/2005/3017/"><span><span class="hlt">Streamflow</span> trends in the United States...from the National <span class="hlt">Streamflow</span> Information Program</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Lins, Harry F.</p> <p>2005-01-01</p> <p>This Fact Sheet is one in a series that highlights information or recent research findings from the USGS National <span class="hlt">Streamflow</span> Information Program (NSIP). The investigations and scientific results reported in this series require a nationally consistent streamgaging network with stable long-term monitoring sites and a rigorous program of data quality assurance, management, archiving, and synthesis. NSIP produces multi-purpose, unbiased surface water information that is readily accessible to all.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.water.usgs.gov/sir2004-5157/','USGSPUBS'); return false;" href="http://pubs.water.usgs.gov/sir2004-5157/"><span>August median <span class="hlt">streamflow</span> on ungaged streams in Eastern Coastal Maine</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Lombard, Pamela J.</p> <p>2004-01-01</p> <p>Methods for estimating August median <span class="hlt">streamflow</span> were developed for ungaged, unregulated streams in eastern coastal Maine. The methods apply to streams with drainage areas ranging in size from 0.04 to 73.2 square miles and fraction of basin underlain by a sand and gravel aquifer ranging from 0 to 71 percent. The equations were developed with data from three long-term (greater than or equal to 10 years of record) continuous-record <span class="hlt">streamflow</span>-gaging stations, 23 partial-record <span class="hlt">streamflow</span>- gaging stations, and 5 short-term (less than 10 years of record) continuous-record <span class="hlt">streamflow</span>-gaging stations. A mathematical technique for estimating a standard low-flow statistic, August median <span class="hlt">streamflow</span>, at partial-record <span class="hlt">streamflow</span>-gaging stations and short-term continuous-record <span class="hlt">streamflow</span>-gaging stations was applied by relating base-flow measurements at these stations to concurrent daily <span class="hlt">streamflows</span> at nearby long-term continuous-record <span class="hlt">streamflow</span>-gaging stations (index stations). Generalized least-squares regression analysis (GLS) was used to relate estimates of August median <span class="hlt">streamflow</span> at <span class="hlt">streamflow</span>-gaging stations to basin characteristics at these same stations to develop equations that can be applied to estimate August median <span class="hlt">streamflow</span> on ungaged streams. GLS accounts for different periods of record at the gaging stations and the cross correlation of concurrent <span class="hlt">streamflows</span> among gaging stations. Thirty-one stations were used for the final regression equations. Two basin characteristics?drainage area and fraction of basin underlain by a sand and gravel aquifer?are used in the calculated regression equation to estimate August median <span class="hlt">streamflow</span> for ungaged streams. The equation has an average standard error of prediction from -27 to 38 percent. A one-variable equation uses only drainage area to estimate August median <span class="hlt">streamflow</span> when less accuracy is acceptable. This equation has an average standard error of prediction from -30 to 43 percent. Model error is larger than</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2000WRR....36.2287G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2000WRR....36.2287G"><span>Simulation of <span class="hlt">snowmelt</span> in a subarctic spruce woodland: 2. Open woodland model</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Giesbrecht, Mark A.; Woo, Ming-Ko</p> <p>2000-08-01</p> <p>A model is presented to simulate <span class="hlt">snowmelt</span> in a subarctic woodland using a Geographic Information System to express the spatial distribution of snow and the pattern of trees and their shifting shadows during the day. The woodland is distinguished into several zone types, including openings under the Sun and in the shade, zones beneath the tree canopy, and the tree trunks. Meteorological data obtained at an open site are transposed to each zone for the calculation of melt rates. The wooded experimental plot is subdivided into 2×2 m2 grid cells, each with different fractional areas occupied by various zone types. Melt rates at each cell are obtained by weighting the zonal melt with these fractional areas. Despite some limitations the model provides a spatial dimension to <span class="hlt">snowmelt</span> in the woodland and yields mean melt values that enhance the representation of the forest melt conditions conventionally obtained using calculations for single points.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/6884286','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/6884286"><span>Climatic fluctuations and the timing of west coast <span class="hlt">streamflow</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Aguado, E. ); Cayan, D.; Riddle, L. ); Roos, M. )</p> <p>1992-12-01</p> <p>Since about 1950 there has been a trend in the California Sierra Nevada toward a decreasing portion of the total annual <span class="hlt">streamflow</span> occurring during April through July, while the <span class="hlt">streamflow</span> during autumn and winter has increased. This trend not only has important ramifications with regard to water mangement, it also brings up the question of whether this represents a shift toward earlier release of the snowpack resulting from greenhouse warming. Therefore, the observed record has been examined in terms of relative influences of temperature and precipitation anomalies on the timing of <span class="hlt">streamflow</span> in this region. To carry out this study, the fraction of annual <span class="hlt">streamflow</span> (called the fractional <span class="hlt">streamflow</span>) occurring in November-January (NDJ), February-April (FMA), and May-July (MJJ) at low, medium and high elevation basins in California and Oregon was examined. Linear regression models were used to relate precipitation and temperature to the fractional <span class="hlt">streamflow</span> at the three elevations for each season. Composites of monthly temperature and precipitation were employed to further examine the fractional <span class="hlt">streamflow</span> in its high and low tercile extremes. Long time series of climatic and hydrologic data were also looked at to infer the causes in the trend toward earlier runoff. 14 refs., 13 figs., 4 tabs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AdWR...71...55Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AdWR...71...55Z"><span>Forecast-skill-based simulation of <span class="hlt">streamflow</span> forecasts</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhao, Tongtiegang; Zhao, Jianshi</p> <p>2014-09-01</p> <p><span class="hlt">Streamflow</span> forecasts are updated periodically in real time, thereby facilitating forecast evolution. This study proposes a forecast-skill-based model of forecast evolution that is able to simulate dynamically updated <span class="hlt">streamflow</span> forecasts. The proposed model applies stochastic models that deal with <span class="hlt">streamflow</span> variability to generate <span class="hlt">streamflow</span> scenarios, which represent cases without forecast skill of future <span class="hlt">streamflow</span>. The model then employs a coefficient of prediction to determine forecast skill and to quantify the <span class="hlt">streamflow</span> variability ratio explained by the forecast. By updating the coefficients of prediction periodically, the model efficiently captures the evolution of <span class="hlt">streamflow</span> forecast. Simulated forecast uncertainty increases with increasing lead time; and simulated uncertainty during a specific future period decreases over time. We combine the statistical model with an optimization model and design a hypothetical case study of reservoir operation. The results indicate the significance of forecast skill in forecast-based reservoir operation. Shortage index reduces as forecast skill increases and ensemble forecast outperforms deterministic forecast at a similar forecast skill level. Moreover, an effective forecast horizon exists beyond which more forecast information does not contribute to reservoir operation and higher forecast skill results in longer effective forecast horizon. The results illustrate that the statistical model is efficient in simulating forecast evolution and facilitates analysis of forecast-based decision making.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70020858','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70020858"><span>Estimating ice-affected <span class="hlt">streamflow</span> by extended Kalman filtering</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Holtschlag, D.J.; Grewal, M.S.</p> <p>1998-01-01</p> <p>An extended Kalman filter was developed to automate the real-time estimation of ice-affected <span class="hlt">streamflow</span> on the basis of routine measurements of stream stage and air temperature and on the relation between stage and <span class="hlt">streamflow</span> during open-water (ice-free) conditions. The filter accommodates three dynamic modes of ice effects: sudden formation/ablation, stable ice conditions, and eventual elimination. The utility of the filter was evaluated by applying it to historical data from two long-term <span class="hlt">streamflow</span>-gauging stations, St. John River at Dickey, Maine and Platte River at North Bend, Nebr. Results indicate that the filter was stable and that parameters converged for both stations, producing <span class="hlt">streamflow</span> estimates that are highly correlated with published values. For the Maine station, logarithms of estimated <span class="hlt">streamflows</span> are within 8% of the logarithms of published values 87.2% of the time during periods of ice effects and within 15% 96.6% of the time. Similarly, for the Nebraska station, logarithms of estimated <span class="hlt">streamflows</span> are within 8% of the logarithms of published values 90.7% of the time and within 15% 97.7% of the time. In addition, the correlation between temporal updates and published <span class="hlt">streamflows</span> on days of direct measurements at the Maine station was 0.777 and 0.998 for ice-affected and open-water periods, respectively; for the Nebraska station, corresponding correlations were 0.864 and 0.997.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70016285','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70016285"><span>New method for calculating a mathematical expression for <span class="hlt">streamflow</span> recession</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Rutledge, Albert T.</p> <p>1991-01-01</p> <p>An empirical method has been devised to calculate the master recession curve, which is a mathematical expression for <span class="hlt">streamflow</span> recession during times of negligible direct runoff. The method is based on the assumption that the storage-delay factor, which is the time per log cycle of <span class="hlt">streamflow</span> recession, varies linearly with the logarithm of <span class="hlt">streamflow</span>. The resulting master recession curve can be nonlinear. The method can be executed by a computer program that reads a data file of daily mean <span class="hlt">streamflow</span>, then allows the user to select several near-linear segments of <span class="hlt">streamflow</span> recession. The storage-delay factor for each segment is one of the coefficients of the equation that results from linear least-squares regression. Using results for each recession segment, a mathematical expression of the storage-delay factor as a function of the log of <span class="hlt">streamflow</span> is determined by linear least-squares regression. The master recession curve, which is a second-order polynomial expression for time as a function of log of <span class="hlt">streamflow</span>, is then derived using the coefficients of this function.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFM.H13A1303F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFM.H13A1303F"><span>Catchment classification and similarity using correlation in <span class="hlt">streamflow</span> time series</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fleming, B.; Archfield, S. A.</p> <p>2012-12-01</p> <p>Catchment classification is an important component of hydrologic analyses, particularly for linking changes in ecological integrity to <span class="hlt">streamflow</span> alteration, transferring time series or model parameters from gauged to ungauged locations, and as a way to understand the similarity in the response of catchments to change. Metrics of similarity used in catchment classification have ranged from aggregate catchment properties such as geologic or climate characteristics to variables derived from the daily <span class="hlt">streamflow</span> hydrograph; however, no one set of classification variables can fully describe similarity between catchments as the variables used for such assessments often depend on the question being asked. We propose an alternative method based on similarity for hydrologic classification: correlation between the daily <span class="hlt">streamflow</span> time series. If one assumes that the <span class="hlt">streamflow</span> signal is the integrated response of a catchment to both climate and geology, then the strength of correlation in <span class="hlt">streamflow</span> between two catchments is a measure of the strength of similarity in hydrologic response between those two catchments. Using the nonparametric Spearman rho correlation coefficient between <span class="hlt">streamflow</span> time series at 54 unregulated and unaltered streamgauges in the mid-Atlantic United States, we show that correlation is a parsimonious classification metric that results in physically interpretable classes. Using the correlation between the deseasonalized <span class="hlt">streamflow</span> time series and reclassifying the streamgauges, we also find that seasonality plays an important role in understanding catchment flow dynamics, especially those that can be linked to ecological response and similarity although not to a large extent in this study area.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.usgs.gov/sir/2013/5080/pdf/sir2013-5080.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/sir/2013/5080/pdf/sir2013-5080.pdf"><span>Modeled future peak <span class="hlt">streamflows</span> in four coastal Maine rivers</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Hodgkins, Glenn A.; Dudley, Robert W.</p> <p>2013-01-01</p> <p>To safely and economically design bridges and culverts, it is necessary to compute the magnitude of peak <span class="hlt">streamflows</span> that have specified annual exceedance probabilities (AEPs). Annual precipitation and air temperature in the northeastern United States are, in general, projected to increase during the 21st century. It is therefore important for engineers and resource managers to understand how peak flows may change in the future. This report, prepared in cooperation with the Maine Department of Transportation (MaineDOT), presents modeled changes in peak flows at four basins in coastal Maine on the basis of projected changes in air temperature and precipitation. To estimate future peak <span class="hlt">streamflows</span> at the four basins in this study, historical values for climate (temperature and precipitation) in the basins were adjusted by different amounts and input to a hydrologic model of each study basin. To encompass the projected changes in climate in coastal Maine by the end of the 21st century, air temperatures were adjusted by four different amounts, from -3.6 degrees Fahrenheit (ºF) (-2 degrees Celsius (ºC)) to +10.8 ºF (+6 ºC) of observed temperatures. Precipitation was adjusted by three different percentage values from -15 percent to +30 percent of observed precipitation. The resulting 20 combinations of temperature and precipitation changes (includes the no-change scenarios) were input to Precipitation-Runoff Modeling System (PRMS) watershed models, and annual daily maximum peak flows were calculated for each combination. Modeled peak flows from the adjusted changes in temperature and precipitation were compared to unadjusted (historical) modeled peak flows. Annual daily maximum peak flows increase or decrease, depending on whether temperature or precipitation is adjusted; increases in air temperature (with no change in precipitation) lead to decreases in peak flows, whereas increases in precipitation (with no change in temperature) lead to increases in peak flows. As</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70015726','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70015726"><span>Estimating monthly <span class="hlt">streamflow</span> values by cokriging</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Solow, A.R.; Gorelick, S.M.</p> <p>1986-01-01</p> <p>Cokriging is applied to estimation of missing monthly <span class="hlt">streamflow</span> values in three records from gaging stations in west central Virginia. Missing values are estimated from optimal consideration of the pattern of auto- and cross-correlation among standardized residual log-flow records. Investigation of the sensitivity of estimation to data configuration showed that when observations are available within two months of a missing value, estimation is improved by accounting for correlation. Concurrent and lag-one observations tend to screen the influence of other available observations. Three models of covariance structure in residual log-flow records are compared using cross-validation. Models differ in how much monthly variation they allow in covariance. Precision of estimation, reflected in mean squared error (MSE), proved to be insensitive to this choice. Cross-validation is suggested as a tool for choosing an inverse transformation when an initial nonlinear transformation is applied to flow values. ?? 1986 Plenum Publishing Corporation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70171294','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70171294"><span>Climate and <span class="hlt">streamflow</span> of Puerto Rico</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Giusti, E.V.; Lopez, M.A.</p> <p>1967-01-01</p> <p>THE PRESENTLY AVAILABLE DATA ON <span class="hlt">STREAMFLOW</span>, RUNOFF RAINFALL, AND TEMPERATURE OFPUERTO RICO ARE EVALUATED, ALTHOUGH THE PERIOD OF RECORD IS VERY SHORT, WITH A VIEW TO CONTRIBUTING TO THE KNOWLEDGE OF HYDROLOGY OF TROPICAL ISLANDS. THE AVERAGE ANNUAL STREAMFLOW IN PUERTO RICO IS 56% OF THE ANNUAL RAINFALL, OR 15% MORE THAN IN THE EASTERN PIEDMONT OF THE U S WHERE IT IS 30%. CLIMATE IS ASSUMED TO BE RESPONSIBLE FOR THIS DIFFERENCE AS WELL AS FOR THE DIFFERENCES OF THE FLOWS OF PUERTORICAN STREAMS WHICH VARY FROM 15 TO 85% OF THE ANNUAL RAINFALL. VARIATIONS IN THE CLIMATE OF PUERTO RICOARE SHOWN BY THORNTHWAITE'S CLIMATIC INDEX ON A MAP OF THE ISLAND, AND THE VARIATIONS OF THESTREAMFLOW TO RAINFALL RATIOS OF PUERTO RICAN STREAMS ARE SHOWN TO BE RELATED TO THORNTHWAITE'S CLIMATIC INDEX. (KNAPP-USGS) </p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19760009481','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19760009481"><span>Use of areal snow cover measurements from ERTS-1 imagery in <span class="hlt">snowmelt</span>-runoff relationships in Arizona</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Aul, J. S.; Ffolliott, P. F.</p> <p>1975-01-01</p> <p>Methods of interpreting ERTS-1 imagery to measure areal snow cover were analyzed. Relationship of areal snow cover and runoff were among the objectives in this study of ERTS-1 imagery use for forecasting <span class="hlt">snowmelt</span>-runoff relationships.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1982JGR....87.1347B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1982JGR....87.1347B"><span>Effect of ashfall on <span class="hlt">snowmelt</span> rate at Paradise, Mount Rainier, Washington</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Brown, Bert E.</p> <p>1982-02-01</p> <p>Snowpack data and temperature information in the form of degree-day calculations are analyzed for Paradise, Mt. Rainier, for the weeks following the May 18, 1980, eruption of Mt. St. Helens. The figures are compared with similar computations for the preceding 25 years. The results show that the dark ash layer increased the <span class="hlt">snowmelt</span> rate by some 40% over what would have been expected from ambient temperatures.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li class="active"><span>22</span></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_22 --> <div id="page_23" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li class="active"><span>23</span></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="441"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFM.C51D0680H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFM.C51D0680H"><span>Interactions Between Hydroclimate and Soil Properties Control the Risk For Altered Hydrologic Partitioning From Changing <span class="hlt">Snowmelt</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Harpold, A. A.; Longley, P.; Weiss, S. G.; Kampf, S. K.; Flint, A. L.</p> <p>2016-12-01</p> <p>Mountain <span class="hlt">snowmelt</span> is a critical water source for downstream human populations and local ecosystem health. Here we explore the relatively unknown hydrologic consequences of two observed trends in Western U.S. snowpack dynamics: 1) shifts from snow to rain and 2) earlier and slower <span class="hlt">snowmelt</span>. We apply two modeling approaches to tease apart the hydrologic effects of altered winter water inputs: 1) highly resolved one-dimensional HYDRUS modeling based on the Richard's equation at intensively measured sites and 2) the distributed Basin Characterization Model (BCM) over the Southwestern U.S. with relatively simple subsurface processes. The HYDRUS model was trained using observations from ten Snow Telemetry (SNOTEL) sites to investigate drainage below the root zone under scenarios of rain only and slower <span class="hlt">snowmelt</span>. We found that shifts to rain-only regimes and earlier <span class="hlt">snowmelt</span> both resulted in greater fluxes below the root zone using the measured soil depths. However, drainage fluxes and differences among scenarios diminished precipitously when rooting depths were increased to account for uncertainty. Next using the BCM, we compared water partitioning during historical runs from 1940-2014 to a scenario with all precipitation as rain but identical climate. We found that ET generally increased from eliminating snowpack sublimation. Recharge and runoff exhibited diverging responses to shifting precipitation regimes; runoff typically decreased and recharge increased, with the exception of areas in western and southern California and central Arizona. The observed changes in annual runoff and recharge were primarily caused by changes in input intensity and not changes in input timing. Runoff was most sensitive in areas with wet winters and low soil water storage. Both modeling approaches corroborated the potential for diverging changes in mountain water budgets from altered winter water inputs that will be mediated precipitation regime (i.e. precipitation intensity and timing</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016WRR....52.4905B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016WRR....52.4905B"><span>Dissolved organic matter transport reflects hillslope to stream connectivity during <span class="hlt">snowmelt</span> in a montane catchment</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Burns, Margaret A.; Barnard, Holly R.; Gabor, Rachel S.; McKnight, Diane M.; Brooks, Paul D.</p> <p>2016-06-01</p> <p>Dissolved organic matter (DOM) transport is a key biogeochemical linkage across the terrestrial-aquatic interface in headwater catchments, and quantifying the biological and hydrological controls on DOM composition provides insight into DOM cycling at the catchment scale. We evaluated the mobility of DOM components during <span class="hlt">snowmelt</span> in a montane, semiarid catchment. DOM composition was evaluated on a near-daily basis within the soil and the stream during <span class="hlt">snowmelt</span>, and was compared to groundwater samples using a site-specific parallel factor analysis (PARAFAC) model derived from soil extracts. The fluorescent component loadings in the interstitial soil water and in the groundwater were significantly different and did not temporally change during <span class="hlt">snowmelt</span>. In the stream, a transition occurred during <span class="hlt">snowmelt</span> from fluorescent DOM with higher contributions of amino acid-like components indicative of groundwater to higher humic-like contributions indicative of soil water. Furthermore, we identified a humic-like fluorescent component in the soil water and the stream that is typically only observed in extracted water soluble organic matter from soil which may suggest hillslope to stream connectivity over very short time scales. Qualitative interpretations of changes in stream fluorescent DOM were supported by two end-member mixing analyses of conservative tracers. After normalizing fluorescent DOM loadings for dissolved organic carbon (DOC) concentration, we found that the peak in DOC concentration in the stream was driven by the nonfluorescent fraction of DOM. This study demonstrated how PARAFAC analysis can be used to refine our conceptual models of runoff generation sources, as well as provide a more detailed understanding of stream chemistry dynamics.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFM.C33B0789Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFM.C33B0789Z"><span>Antarctic <span class="hlt">Snowmelt</span> Detected by Diurnal Variations of AMSR-E Brightness Temperature</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zheng, L.; Zhou, C.</p> <p>2016-12-01</p> <p>The ascending passes and descending passes of AMSR-E observed the Antarctic in afternoon (the warmest period) and midnight respectively. The diurnal variations of vertical polarized 36GHz brightness temperature (Tb) was served as a thaw-freeze index (TFI) to detect <span class="hlt">snowmelt</span> in Antarctic ice sheet from 2002 to 2011. A set of controlled experiments based on microwave emission model of layered snow (MEMLS) was used to model the changes of the Tb at 36 GHz in vertical polarization when the snow is about to melt. The simulations show that TFI in thicker and denser snow pack with higher exponential correlation lengths is more sensitive to the emergence of liquid water, and 10K can be a threshold value of TFI to recognize melting snow. Assuming that there is no <span class="hlt">snowmelt</span> in the pixels beyond 3500m, the potential melting area in Antarctica was mapping in advance in order to eliminating the misjudgments of rocky pixels based on the changes of TFI in the places that never melts . The analysis of <span class="hlt">snowmelt</span> suggested the Antarctic ice sheet begin to melt in November and almost totally refreeze in late March of the next year, the daily average melting area turns out to be approximately normally distributed. The annual cumulative melting area showed considerable fluctuations and a slight drop of 5.24×104km2 per year. The cumulative melting area from 2002 to 2011 in Antarctica was 2.44×106 km2. The annual melting days and persistent duration in sustained melting area had an annual decrease of 0.81d/yr and 0.64 d/yr respectively. Antarctic <span class="hlt">snowmelt</span> showed temporal and spatial decreases from 2002 to 2011.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28494297','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28494297"><span>Episodic acidification of 5 rivers in Canada's oil sands during <span class="hlt">snowmelt</span>: A 25-year record.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Alexander, A C; Chambers, P A; Jeffries, D S</p> <p>2017-12-01</p> <p>Episodic acidification during <span class="hlt">snowmelt</span> is a natural phenomenon that can be intensified by acidic deposition from heavy industry. In Canada's oil sands region, acid deposition is estimated to be as much as 5% of the Canadian total and large tracks of northeastern Alberta are considered acid-sensitive because of extensive peatland habitats with poorly weathered soils. To identify the frequency, duration and severity of acidification episodes during <span class="hlt">snowmelt</span> (the predominant hydrological period for delivery of priority pollutants from atmospheric oil sands emissions to surface waters), a 25-year record (1989 to 2014) of automated water quality data (pH, temperature, conductivity) was assembled for 3 rivers along with a shorter record (2012-2014) for another 2 rivers. Acidic episodes (pH<7, ANC<0) were recorded during 39% of all 83 <span class="hlt">snowmelt</span> events. The severity (duration x magnitude) of episodic acidification increased exponentially over the study period (r(2)=0.56, P<0.01) and was strongly correlated (P<0.01) with increasing maximum air temperature and weakly correlated with regional land development (P=0.06). Concentrations of aluminum and 11 priority pollutants (Sb, As, Be, Cd, Cr, Cu, Pb, Se, Ag, Tl and Zn) were greatest (P<0.01) during low (<6.5) pH episodes, particularly when coincident with high discharge, such that aluminum and copper concentrations were at times high enough to pose a risk to juvenile rainbow trout (Oncorhynchus mykiss). Although low pH (pH<6.5) was observed during only 8% of 32 acidification episodes, when present, low pH typically lasted 10days. Episodic surface water acidification during <span class="hlt">snowmelt</span>, and its potential effects on aquatic biota, is therefore an important consideration in the design of long-term monitoring of these typically alkaline (pH=7.72±0.05) rivers. Crown Copyright © 2017. Published by Elsevier B.V. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.B11D0465P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.B11D0465P"><span>Mercury Transport During <span class="hlt">Snowmelt</span> in Three Mountain Watersheds in Northern Utah, USA</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Packer, B. N.; Carling, G. T.; Tingey, D. G.</p> <p>2015-12-01</p> <p>Mercury (Hg) transport during <span class="hlt">snowmelt</span> is widely recognized as a significant source of Hg to high elevation lakes and streams. However, it is not well understood to what extent Hg is associated with suspended sediment versus dissolved organic matter during <span class="hlt">snowmelt</span> runoff. To investigate Hg transport during <span class="hlt">snowmelt</span>, we collected samples for filtered and unfiltered total Hg (THg) and dissolved organic carbon (DOC) in snowpack and <span class="hlt">snowmelt</span> runoff across three snow-dominated watersheds in northern Utah: Logan River, Provo River, and Little Cottonwood Creek. The watersheds were selected to cover a range of geologic and hydrologic conditions typical of the Rocky Mountain region. Initial results show that snowpack THg concentrations were similar across the watersheds (0.87 - 1.69 ng/L) but river THg concentrations were highly variable. The Provo River showed the highest THg concentrations approaching 6 ng/L during peak flows, whereas maximum THg concentrations in the Logan River were <2 ng/L. Little Cottonwood Creek showed intermediate THg concentrations. THg and DOC showed strong positive correlation in the Provo River (R2=0.68) but were not correlated in the Logan River (R2=0.04). Notably, the Provo River showed the highest fraction of "dissolved" THg (calculated as the fraction of filtered/unfiltered concentration) averaging 75% compared with the other sites where the "dissolved" fraction was <45%. These results suggest that the majority of THg is transported in association with DOC in the Provo River but is more strongly associated with suspended sediments in the Logan River and Little Cottonwood Creek. These findings have implications for understanding Hg cycling in the Provo River watershed where Jordanelle Reservoir has fish consumption advisories due elevated Hg concentrations. The dissolved load of THg, possibly associated with DOC, is likely methylated in Jordanelle Reservoir where it bio-accumulates up the food web.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.H51H0711G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.H51H0711G"><span>Forest Harvesting Impacts on Attributes of the Flow Regime in <span class="hlt">Snowmelt</span> Regions</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Green, K.; Alila, Y.</p> <p>2014-12-01</p> <p>Recent studies have revealed how forest cover removal can alter the frequency and magnitude of annual peak flows. However, to fully understand the impacts of land cover changes on stream channels, it is necessary to examine how multiple attributes of the flow regime are affected. Changes in the frequency and duration of peaks over threshold (PoT) discharge for sediment mobilization has the potential to alter the dynamics of bedload mobility and channel form in alluvial gravel-bed streams. A meta-analysis investigation of changes in the duration and number of PoT in four <span class="hlt">snowmelt</span> catchments of western North America contributes towards a comprehensive understanding of the influence of harvesting on the <span class="hlt">snowmelt</span> flow regime. Analysis results reveal that harvesting causes the duration and number of PoT of <span class="hlt">snowmelt</span> peak flows to increase and that these increases are generally greater for larger flood quantiles. Such a response indicates that, following harvesting, the hydrograph in all four catchments has become more responsive during the freshet period. In addition harvesting has resulted in increases in the total volume (i.e. duration) of flood peaks so that discharge remains elevated above specific thresholds for longer periods of time. The meta-analysis results suggest that physical basin characteristics including percentage of alpine area, slope aspect, and gradient, elevation and watershed size all play a role in catchment scale response to harvesting-related increases in flood duration and PoT. In snow environments alterations to the flow regime due to forest removal are likely to persist for many decades until sufficient forest regeneration restores stand level processes of snow accumulation and <span class="hlt">snowmelt</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.fs.usda.gov/treesearch/pubs/46424','TREESEARCH'); return false;" href="https://www.fs.usda.gov/treesearch/pubs/46424"><span>Soil freezing effects on sources of nitrogen and carbon leached during <span class="hlt">snowmelt</span></span></a></p> <p><a target="_blank" href="http://www.fs.usda.gov/treesearch/">Treesearch</a></p> <p>John L. Campbell; Andrew B. Reinmann; Pamela H. Templer</p> <p>2014-01-01</p> <p>Soil freezing in winter has been shown to enhance growing season losses of C and N in northern forests. However, less is known about effects of soil freezing on C and N retention during <span class="hlt">snowmelt</span> and the sources of C and N leached, which is important because losses to stream water are greatest during this period. Organic horizon soils (Oi + Oe + Oa) from the Hubbard...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.usgs.gov/sir/2006/5312/','USGSPUBS'); return false;" href="https://pubs.usgs.gov/sir/2006/5312/"><span>A <span class="hlt">Streamflow</span> Statistics (StreamStats) Web Application for Ohio</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Koltun, G.F.; Kula, Stephanie P.; Puskas, Barry M.</p> <p>2006-01-01</p> <p>A StreamStats Web application was developed for Ohio that implements equations for estimating a variety of <span class="hlt">streamflow</span> statistics including the 2-, 5-, 10-, 25-, 50-, 100-, and 500-year peak <span class="hlt">streamflows</span>, mean annual <span class="hlt">streamflow</span>, mean monthly <span class="hlt">streamflows</span>, harmonic mean <span class="hlt">streamflow</span>, and 25th-, 50th-, and 75th-percentile <span class="hlt">streamflows</span>. StreamStats is a Web-based geographic information system application designed to facilitate the estimation of <span class="hlt">streamflow</span> statistics at ungaged locations on streams. StreamStats can also serve precomputed <span class="hlt">streamflow</span> statistics determined from <span class="hlt">streamflow</span>-gaging station data. The basic structure, use, and limitations of StreamStats are described in this report. To facilitate the level of automation required for Ohio's StreamStats application, the technique used by Koltun (2003)1 for computing main-channel slope was replaced with a new computationally robust technique. The new channel-slope characteristic, referred to as SL10-85, differed from the National Hydrography Data based channel slope values (SL) reported by Koltun (2003)1 by an average of -28.3 percent, with the median change being -13.2 percent. In spite of the differences, the two slope measures are strongly correlated. The change in channel slope values resulting from the change in computational method necessitated revision of the full-model equations for flood-peak discharges originally presented by Koltun (2003)1. Average standard errors of prediction for the revised full-model equations presented in this report increased by a small amount over those reported by Koltun (2003)1, with increases ranging from 0.7 to 0.9 percent. Mean percentage changes in the revised regression and weighted flood-frequency estimates relative to regression and weighted estimates reported by Koltun (2003)1 were small, ranging from -0.72 to -0.25 percent and -0.22 to 0.07 percent, respectively.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017HESS...21.1573C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017HESS...21.1573C"><span>Seasonal <span class="hlt">streamflow</span> forecasting by conditioning climatology with precipitation indices</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Crochemore, Louise; Ramos, Maria-Helena; Pappenberger, Florian; Perrin, Charles</p> <p>2017-03-01</p> <p>Many fields, such as drought-risk assessment or reservoir management, can benefit from long-range <span class="hlt">streamflow</span> forecasts. Climatology has long been used in long-range <span class="hlt">streamflow</span> forecasting. Conditioning methods have been proposed to select or weight relevant historical time series from climatology. They are often based on general circulation model (GCM) outputs that are specific to the forecast date due to the initialisation of GCMs on current conditions. This study investigates the impact of conditioning methods on the performance of seasonal <span class="hlt">streamflow</span> forecasts. Four conditioning statistics based on seasonal forecasts of cumulative precipitation and the standardised precipitation index were used to select relevant traces within historical <span class="hlt">streamflows</span> and precipitation respectively. This resulted in eight conditioned <span class="hlt">streamflow</span> forecast scenarios. These scenarios were compared to the climatology of historical <span class="hlt">streamflows</span>, the ensemble <span class="hlt">streamflow</span> prediction approach and the <span class="hlt">streamflow</span> forecasts obtained from ECMWF System 4 precipitation forecasts. The impact of conditioning was assessed in terms of forecast sharpness (spread), reliability, overall performance and low-flow event detection. Results showed that conditioning past observations on seasonal precipitation indices generally improves forecast sharpness, but may reduce reliability, with respect to climatology. Conversely, conditioned ensembles were more reliable but less sharp than <span class="hlt">streamflow</span> forecasts derived from System 4 precipitation. Forecast attributes from conditioned and unconditioned ensembles are illustrated for a case of drought-risk forecasting: the 2003 drought in France. In the case of low-flow forecasting, conditioning results in ensembles that can better assess weekly deficit volumes and durations over a wider range of lead times.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..19.5680K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..19.5680K"><span>An experiment to compare multiple methods for <span class="hlt">streamflow</span> uncertainty estimation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kiang, Julie; McMillan, Hilary; Gazoorian, Chris; Mason, Robert; Le Coz, Jerome; Renard, Benjamin; Mansanarez, Valentin; Westerberg, Ida; Petersen-Øverleir, Asgeir; Reitan, Trond; Sikorska, Anna; Seibert, Jan; Coxon, Gemma; Freer, Jim; Belleville, Arnaud; Hauet, Alexandre</p> <p>2017-04-01</p> <p>Stage-discharge rating curves are used to relate <span class="hlt">streamflow</span> discharge to continuously measured river stage readings to create a continuous record of <span class="hlt">streamflow</span> discharge. The stage-discharge relationship is estimated and refined using discrete <span class="hlt">streamflow</span> measurements over time, during which both the discharge and stage are measured. There is uncertainty in the resulting rating curve due to multiple factors including the curve-fitting process, assumptions on the form of the model used, fluvial geomorphology of natural channels, and the approaches used to extrapolate the rating equation beyond available observations. This rating curve uncertainty leads to uncertainty in the <span class="hlt">streamflow</span> timeseries, and therefore to uncertainty in predictive models that use the <span class="hlt">streamflow</span> data. Many different methods have been proposed in the literature for estimating rating curve uncertainty, differing in mathematical rigor, in the assumptions made about the component errors, and in the information required to implement the method at any given site. This study describes the results of an international experiment to test and compare <span class="hlt">streamflow</span> uncertainty estimation methods from 7 research groups across 9 institutions. The methods range from simple LOWESS fits to more complicated Bayesian methods that consider hydraulic principles directly. We evaluate these different methods when applied to three diverse gauging stations using standardized information (channel characteristics, hydrographs, and <span class="hlt">streamflow</span> measurements). Our results quantify the resultant spread of the stage-discharge curves and compare the level of uncertainty attributed to the <span class="hlt">streamflow</span> records by each different method. We provide insight into the sensitivity of <span class="hlt">streamflow</span> uncertainty bounds to the choice of uncertainty estimation method, and discuss the implications for model uncertainty assessment.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1999HyPr...13.2203H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1999HyPr...13.2203H"><span>Nitrogen dynamics in two high elevation catchments during spring <span class="hlt">snowmelt</span> 1996, Rocky Mountains, Colorado</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Heuer, Kristi; Brooks, Paul D.; Tonnessen, Kathy A.</p> <p>1999-10-01</p> <p>Snowpack, soil, soil leachate, and streamwater samples were analyzed for inorganic nitrogen (N) to quantify the net effect of soil processes on N export during spring <span class="hlt">snowmelt</span>. The two catchments used for this work, Snake River and Deer Creek, are located in Summit County, Colorado and range in elevation from 3350 to 4120 m. Atmospheric N loading to the snowpack, 88 mg N m-2 (=0·88 kg N ha-1), was representative of low N deposition sites in the Rocky Mountains. Potentially mobile inorganic N in soil, 1252 to 1868 mg N m-2, was much greater than N inputs from snow. During spring <span class="hlt">snowmelt</span>, nitrate (NO) leachate from alpine soil, 702 mg N m-2, was significantly greater than from sub-alpine forest and meadow soils (p<0·001). This pattern in soil leachate was consistent with streamwater N concentrations in Deer Creek, indicating the importance of soil processes in regulating N export from these high elevation catchments. Soils may function as sources or sinks of N during spring <span class="hlt">snowmelt</span>; alpine soils were a significant source of N to the stream, while sub-alpine soils were possible N sinks.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003HyPr...17..747U','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003HyPr...17..747U"><span>Concentrations and transport of different forms of phosphorus during <span class="hlt">snowmelt</span> runoff from an illite clay soil</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ulén, Barbro</p> <p>2003-03-01</p> <p>During a 16 day period with pronounced <span class="hlt">snowmelt</span> via surface runoff, high water concentrations (usually 0·4-0·5 mg l-1) of dissolved molybdate-reactive phosphorus (MRP) were detected in surface runoff water from a clay soil of illite type. Other phosphorus fractions defined were: phosphorus in particles with a higher settling coefficient than 80 000 S (SPP); colloidal phosphorus caught on filters with a pore size of 0·2 µm but with a smaller settling coefficient (CPP); and dissolved phosphorus not reacting with molybdate (DUP). The order of concentrations was MRP > SPP > CPP > DUP. Nearly identical amounts of MRP, CPP, and DUP (in total 0·3 kg ha-1) were lost from a grass-clover ley and a ploughed soil. However, more of the heavier phosphorus-containing material was lost from the ploughed area. In drainpipe water, CPP was the largest fraction (28%), and in stream water from mixed arable/forest land, MRP dominated (33%). Loss on ignition of the settling material slowly decreased from 10 to 8% (dry weight) during the <span class="hlt">snowmelt</span> period. Total phosphorus concentrations in the material followed the runoff pattern, with slightly higher phosphorus concentrations during fast runoff. The large amounts of readily dissolved or colloidal-bound phosphorus (70-80%) transported from this clay soil during <span class="hlt">snowmelt</span> are discussed with regard to the use of grass buffer strips as a measure against phosphorus losses from arable land.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/16955885','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/16955885"><span>Organochlorine pesticide and polychlorinated biphenyl concentrations in snow, <span class="hlt">snowmelt</span>, and runoff at Bow Lake, Alberta.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Lafrenière, Melissa J; Blais, Jules M; Sharp, Martin J; Schindler, David W</p> <p>2006-08-15</p> <p>We present analyses of the concentrations of organochlorine (OC) contaminants (including organochlorine pesticides and PCBs) in snow, <span class="hlt">snowmelt</span>, and runoff in glacier and <span class="hlt">snowmelt</span> fed streams at Bow Lake, Alberta in two contrasting hydrological years (1997 and 1998). The study investigates the variability in OC burdens in snow across the catchment, the elution of OCs from the snowpack, and the relationship between OC concentrations in streams and the annual snowpack. Snowpacks in forested sites were thinner and had lower OC concentrations than snowpacks in open or sparsely vegetated sites. The first <span class="hlt">snowmelt</span> samples exhibited very high contaminant concentrations relative to the snowpack, and even the more hydrophobic compounds (Dieldrin, DDTs, and PCBs) were highly concentrated in meltwater. Interannual changes in the mean OC concentrations in streams did not reflect year-to-year changes in the snowpack contaminant concentrations. The results indicate that the extent of glacial ice melt may be more important than mean snowpack burdens as a control on OC concentrations in runoff in glacial catchments.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20120016032','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20120016032"><span>Use of MODIS Snow-Cover Maps for Detecting <span class="hlt">Snowmelt</span> Trends in North America</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Hall, Dorothy K.; Foster, James L.; Riggs, George A.; Robinson, David A.; Hoon-Starr, Jody A.</p> <p>2012-01-01</p> <p>Research has shown that the snow season in the Northern Hemisphere has been getting shorter in recent decades, consistent with documented global temperature increases. Specifically, the snow is melting earlier in the spring allowing for a longer growing season and associated land-cover changes. Here we focus on North America. Using the Moderate-Resolution Imaging Radiometer (MODIS) cloud-gap-filled standard snow-cover data product we can detect a trend toward earlier spring <span class="hlt">snowmelt</span> in the approx 12 years since the MODIS launch. However, not all areas in North America show earlier spring <span class="hlt">snowmelt</span> over the study period. We show examples of springtime <span class="hlt">snowmelt</span> over North America, beginning in March 2000 and extending through the winter of 2012 for all of North America, and for various specific areas such as the Wind River Range in Wyoming and in the Catskill Mountains in New York. We also compare our approx 12-year trends with trends derived from the Rutgers Global Snow Lab snow cover climate-data record.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AGUFM.C33E0699M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AGUFM.C33E0699M"><span>Implication of mountain shading and topographic scaling on energy for <span class="hlt">snowmelt</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Marsh, C.; Pomeroy, J. W.; Spiteri, R.</p> <p>2011-12-01</p> <p>In many parts of the world, <span class="hlt">snowmelt</span> energetics are dominated by incoming solar radiation. This is the case in the Canadian Rockies, where sunny winters result in high insolation. Solar irradiance on the snow surface is affected by the atmosphere, the slope and aspect of the immediate topography, and shading from surrounding terrain. Errors in estimating solar irradiation are cumulative over a season and can lead to large errors in <span class="hlt">snowmelt</span> predictions. Adaptive triangular meshes, a type of unstructured triangular mesh that can adapt to fine-scale processes during model runtime, are more efficient in their use of DEM data than fixed grids when producing solar irradiance maps. An experimental design to calculate the effect of changes in DEM resolution on ad