Gregory E Schwarz
Gregory Schwarz is an Economist with the USGS Water Resources Mission Area.
Science and Products
Filter Total Items: 66
Nutrient Trends in Streams and Rivers of the United States, 1993-2003
Trends in streamflow and concentrations and loads of total phosphorus, total nitrogen, and nitrate were determined for the period from 1993 to 2003 in selected streams and ricers of the United States. Flow-adjusted trends in concentration (the trends that would have occurred in the absence of natural chances in streamflow), non-flow-adjusted trends in concentration (the trends resulting from both
Authors
Lori A. Sprague, David K. Mueller, Gregory E. Schwarz, David L. Lorenz
RESIS-II: An Updated Version of the Original Reservoir Sedimentation Survey Information System (RESIS) Database
The Reservoir Sedimentation Survey Information System (RESIS) database, originally compiled by the Soil Conservation Service (now the Natural Resources Conservation Service) in collaboration with the Texas Agricultural Experiment Station, is the most comprehensive compilation of data from reservoir sedimentation surveys throughout the conterminous United States (U.S.). The database is a cumulative
Authors
Katherine V. Ackerman, David M. Mixon, Eric T. Sundquist, Robert F. Stallard, Gregory E. Schwarz, David W. Stewart
Recent technologies usher in new era of coastal geomorphology research
[No abstract available]
Authors
J. R. Gray, J.M. Bernard, G. E. Schwarz, D. W. Stewart, K.T. Ray
Online interactive U.S. Reservoir Sedimentation Survey Database
In April 2009, the U.S. Geological Survey and the Natural Resources Conservation Service (prior to 1994, the Soil Conservation Service) created the Reservoir Sedimentation Survey Database (RESSED) and Web site, the most comprehensive compilation of data from reservoir bathymetric and dry basin surveys in the United States. RESSED data can be useful for a number of purposes, including calculating c
Authors
J.B. Gray, J.M. Bernard, G. E. Schwarz, D. W. Stewart, K.T. Ray
Incorporating uncertainty into the ranking of SPARROW model nutrient yields from Mississippi/Atchafalaya River basin watersheds
Excessive loads of nutrients transported by tributary rivers have been linked to hypoxia in the Gulf of Mexico. Management efforts to reduce the hypoxic zone in the Gulf of Mexico and improve the water quality of rivers and streams could benefit from targeting nutrient reductions toward watersheds with the highest nutrient yields delivered to sensitive downstream waters. One challenge is that most
Authors
Dale M. Robertson, Gregory E. Schwarz, David A. Saad, Richard B. Alexander
A Preliminary SPARROW Model of Suspended Sediment for the Conterminous United States
This report describes the results of a preliminary Spatially Referenced Regression on Watershed attributes (SPARROW) model of suspended sediment for the conterminous United States. The analysis is based on flux estimates compiled from more than 1,800 long-term monitoring stations operated by the U.S. Geological Survey (USGS) during the period 1975-2007. The SPARROW model is structured on the Reach
Authors
Gregory E. Schwarz
Differences in phosphorus and nitrogen delivery to the Gulf of Mexico from the Mississippi River Basin
Seasonal hypoxia in the northern Gulf of Mexico has been linked to increased nitrogen fluxes from the Mississippi and Atchafalaya River Basins, though recent evidence shows that phosphorus also influences productivity in the Gulf. We developed a spatially explicit and structurally detailed SPARROW water-quality model that reveals important differences in the sources and transport processes that co
Authors
R. B. Alexander, R. A. Smith, G. E. Schwarz, E. W. Boyer, J.V. Nolan, J. W. Brakebill
Nutrient and Suspended-Sediment Transport and Trends in the Columbia River and Puget Sound Basins, 1993-2003
This study focused on three areas that might be of interest to water-quality managers in the Pacific Northwest: (1) annual loads of total nitrogen (TN), total phosphorus (TP) and suspended sediment (SS) transported through the Columbia River and Puget Sound Basins, (2) annual yields of TN, TP, and SS relative to differences in landscape and climatic conditions between subbasin catchments (drainage
Authors
Daniel R. Wise, Frank A. Rinella, Joseph F. Rinella, Greg J. Fuhrer, Sandra S. Embrey, Gregory M. Clark, Gregory E. Schwarz, Steven Sobieszczyk
The role of headwater streams in downstream water quality
Knowledge of headwater influences on the water-quality and flow conditions of downstream waters is essential to water-resource management at all governmental levels; this includes recent court decisions on the jurisdiction of the Federal Clean Water Act (CWA) over upland areas that contribute to larger downstream water bodies. We review current watershed research and use a water-quality model to i
Authors
R. B. Alexander, E. W. Boyer, R. A. Smith, G. E. Schwarz, R. B. Moore
Changes in streamflow and water quality in selected nontidal basins in the Chesapeake Bay Watershed, 1985-2004
As part of an annual evaluation of water-quality conditions by the Chesapeake Bay Program, water-quality and streamflow data from 32 sites in nontidal parts of the Chesapeake Bay watershed were analyzed to document annual nutrient and sediment trends for 1985 through 2004. This study also formalized different trend tests and methodologies used in assessing the effectiveness of man-agement actions
Authors
Michael J. Langland, Jeff P. Raffensperger, Douglas Moyer, Jurate M. Landwehr, Gregory E. Schwarz
Section 3. The SPARROW Surface Water-Quality Model—Theory, application and user documentation
SPARROW (SPAtially Referenced Regressions On Watershed attributes) is a watershed modeling technique for relating water-quality measurements made at a network of monitoring stations to attributes of the watersheds containing the stations. The core of the model consists of a nonlinear regression equation describing the non-conservative transport of contaminants from point and diffuse sources on lan
Authors
Gregory Schwarz, Anne B. Hoos, R. B. Alexander, R. A. Smith
Estimation of nutrient sources and transport for New Zealand using the hybrid mechanistic-statistical model SPARROW
The hybrid mechanistic-statistical catchment model SPARROW was applied to predict the mean annual load of nitrogen and phosphorus in streams throughout New Zealand (270,000 km2). The loads from land areas, point sources, and erosion are routed through the drainage network (576,300 reaches) with first-order stream decay and attenuation in lakes and reservoirs. Model parameters were determined by ca
Authors
A.H. Elliot, R. B. Alexander, G. E. Schwarz, Ude Shankar, J.P.S. Sukias, Graham B. McBride
Science and Products
Filter Total Items: 66
Nutrient Trends in Streams and Rivers of the United States, 1993-2003
Trends in streamflow and concentrations and loads of total phosphorus, total nitrogen, and nitrate were determined for the period from 1993 to 2003 in selected streams and ricers of the United States. Flow-adjusted trends in concentration (the trends that would have occurred in the absence of natural chances in streamflow), non-flow-adjusted trends in concentration (the trends resulting from both
Authors
Lori A. Sprague, David K. Mueller, Gregory E. Schwarz, David L. Lorenz
RESIS-II: An Updated Version of the Original Reservoir Sedimentation Survey Information System (RESIS) Database
The Reservoir Sedimentation Survey Information System (RESIS) database, originally compiled by the Soil Conservation Service (now the Natural Resources Conservation Service) in collaboration with the Texas Agricultural Experiment Station, is the most comprehensive compilation of data from reservoir sedimentation surveys throughout the conterminous United States (U.S.). The database is a cumulative
Authors
Katherine V. Ackerman, David M. Mixon, Eric T. Sundquist, Robert F. Stallard, Gregory E. Schwarz, David W. Stewart
Recent technologies usher in new era of coastal geomorphology research
[No abstract available]
Authors
J. R. Gray, J.M. Bernard, G. E. Schwarz, D. W. Stewart, K.T. Ray
Online interactive U.S. Reservoir Sedimentation Survey Database
In April 2009, the U.S. Geological Survey and the Natural Resources Conservation Service (prior to 1994, the Soil Conservation Service) created the Reservoir Sedimentation Survey Database (RESSED) and Web site, the most comprehensive compilation of data from reservoir bathymetric and dry basin surveys in the United States. RESSED data can be useful for a number of purposes, including calculating c
Authors
J.B. Gray, J.M. Bernard, G. E. Schwarz, D. W. Stewart, K.T. Ray
Incorporating uncertainty into the ranking of SPARROW model nutrient yields from Mississippi/Atchafalaya River basin watersheds
Excessive loads of nutrients transported by tributary rivers have been linked to hypoxia in the Gulf of Mexico. Management efforts to reduce the hypoxic zone in the Gulf of Mexico and improve the water quality of rivers and streams could benefit from targeting nutrient reductions toward watersheds with the highest nutrient yields delivered to sensitive downstream waters. One challenge is that most
Authors
Dale M. Robertson, Gregory E. Schwarz, David A. Saad, Richard B. Alexander
A Preliminary SPARROW Model of Suspended Sediment for the Conterminous United States
This report describes the results of a preliminary Spatially Referenced Regression on Watershed attributes (SPARROW) model of suspended sediment for the conterminous United States. The analysis is based on flux estimates compiled from more than 1,800 long-term monitoring stations operated by the U.S. Geological Survey (USGS) during the period 1975-2007. The SPARROW model is structured on the Reach
Authors
Gregory E. Schwarz
Differences in phosphorus and nitrogen delivery to the Gulf of Mexico from the Mississippi River Basin
Seasonal hypoxia in the northern Gulf of Mexico has been linked to increased nitrogen fluxes from the Mississippi and Atchafalaya River Basins, though recent evidence shows that phosphorus also influences productivity in the Gulf. We developed a spatially explicit and structurally detailed SPARROW water-quality model that reveals important differences in the sources and transport processes that co
Authors
R. B. Alexander, R. A. Smith, G. E. Schwarz, E. W. Boyer, J.V. Nolan, J. W. Brakebill
Nutrient and Suspended-Sediment Transport and Trends in the Columbia River and Puget Sound Basins, 1993-2003
This study focused on three areas that might be of interest to water-quality managers in the Pacific Northwest: (1) annual loads of total nitrogen (TN), total phosphorus (TP) and suspended sediment (SS) transported through the Columbia River and Puget Sound Basins, (2) annual yields of TN, TP, and SS relative to differences in landscape and climatic conditions between subbasin catchments (drainage
Authors
Daniel R. Wise, Frank A. Rinella, Joseph F. Rinella, Greg J. Fuhrer, Sandra S. Embrey, Gregory M. Clark, Gregory E. Schwarz, Steven Sobieszczyk
The role of headwater streams in downstream water quality
Knowledge of headwater influences on the water-quality and flow conditions of downstream waters is essential to water-resource management at all governmental levels; this includes recent court decisions on the jurisdiction of the Federal Clean Water Act (CWA) over upland areas that contribute to larger downstream water bodies. We review current watershed research and use a water-quality model to i
Authors
R. B. Alexander, E. W. Boyer, R. A. Smith, G. E. Schwarz, R. B. Moore
Changes in streamflow and water quality in selected nontidal basins in the Chesapeake Bay Watershed, 1985-2004
As part of an annual evaluation of water-quality conditions by the Chesapeake Bay Program, water-quality and streamflow data from 32 sites in nontidal parts of the Chesapeake Bay watershed were analyzed to document annual nutrient and sediment trends for 1985 through 2004. This study also formalized different trend tests and methodologies used in assessing the effectiveness of man-agement actions
Authors
Michael J. Langland, Jeff P. Raffensperger, Douglas Moyer, Jurate M. Landwehr, Gregory E. Schwarz
Section 3. The SPARROW Surface Water-Quality Model—Theory, application and user documentation
SPARROW (SPAtially Referenced Regressions On Watershed attributes) is a watershed modeling technique for relating water-quality measurements made at a network of monitoring stations to attributes of the watersheds containing the stations. The core of the model consists of a nonlinear regression equation describing the non-conservative transport of contaminants from point and diffuse sources on lan
Authors
Gregory Schwarz, Anne B. Hoos, R. B. Alexander, R. A. Smith
Estimation of nutrient sources and transport for New Zealand using the hybrid mechanistic-statistical model SPARROW
The hybrid mechanistic-statistical catchment model SPARROW was applied to predict the mean annual load of nitrogen and phosphorus in streams throughout New Zealand (270,000 km2). The loads from land areas, point sources, and erosion are routed through the drainage network (576,300 reaches) with first-order stream decay and attenuation in lakes and reservoirs. Model parameters were determined by ca
Authors
A.H. Elliot, R. B. Alexander, G. E. Schwarz, Ude Shankar, J.P.S. Sukias, Graham B. McBride