Gregory E Schwarz
Gregory Schwarz is an Economist with the USGS Water Resources Mission Area.
Science and Products
Filter Total Items: 67
Spatial variability in nutrient transport by HUC8, state, and subbasin based on Mississippi/Atchafalaya River Basin SPARROW models
Nitrogen (N) and phosphorus (P) loading from the Mississippi/Atchafalaya River Basin (MARB) has been linked to hypoxia in the Gulf of Mexico. With geospatial datasets for 2002, including inputs from wastewater treatment plants (WWTPs), and monitored loads throughout the MARB, SPAtially Referenced Regression On Watershed attributes (SPARROW) watershed models were constructed specifically for the MA
Authors
Dale M. Robertson, David A. Saad, Gregory E. Schwarz
Spatially explicit modeling to evaluate regional stream water quality
Spatially referenced regressions on watershed attributes (SPARROW) models have been developed and applied over the past two decades to address the need for large-scale, spatially explicit information on stream water quality conditions. The strength of SPARROW models is that they describe the primary environmental processes that affect the supply and transport of contaminant mass in watersheds, bas
Authors
Stephen D. Preston, Richard B. Alexander, Gregory Schwarz, Richard A. Smith
Estimated nitrogen loads from selected tributaries in Connecticut draining to Long Island Sound, 1999–2009
The total nitrogen load to Long Island Sound from Connecticut and contributing areas to the north was estimated for October 1998 to September 2009. Discrete measurements of total nitrogen concentrations and continuous flow data from 37 water-quality monitoring stations in the Long Island Sound watershed were used to compute total annual nitrogen yields and loads. Total annual computed yields and b
Authors
John R. Mullaney, Gregory E. Schwarz
Regional regression models of watershed suspended-sediment discharge for the eastern United States
Estimates of mean annual watershed sediment discharge, derived from long-term measurements of suspended-sediment concentration and streamflow, often are not available at locations of interest. The goal of this study was to develop multivariate regression models to enable prediction of mean annual suspended-sediment discharge from available basin characteristics useful for most ungaged river locati
Authors
David C. Roman, Richard M. Vogel, Gregory E. Schwarz
Nutrient concentrations and loads in the northeastern United States - Status and trends, 1975-2003
The U.S. Geological Survey (USGS) National Water-Quality Assessment Program (NAWQA) began regional studies in 2003 to synthesize information on nutrient concentrations, trends, stream loads, and sources. In the northeastern United States, a study area that extends from Maine to central Virginia, nutrient data were evaluated for 130 USGS water-quality monitoring stations. Nutrient data were analyze
Authors
Elaine C. Todd Trench, Richard B. Moore, Elizabeth A. Ahearn, John R. Mullaney, R. Edward Hickman, Gregory E. Schwarz
A multi-agency nutrient dataset used to estimate loads, improve monitoring design, and calibrate regional nutrient SPARROW models
Stream-loading information was compiled from federal, state, and local agencies, and selected universities as part of an effort to develop regional SPAtially Referenced Regressions On Watershed attributes (SPARROW) models to help describe the distribution, sources, and transport of nutrients in streams throughout much of the United States. After screening, 2,739 sites, sampled by 73 agencies, were
Authors
David A. Saad, Gregory E. Schwarz, Dale M. Robertson, Nathaniel Booth
Factors affecting stream nutrient loads: A synthesis of regional SPARROW model results for the continental United States
We compared the results of 12 recently calibrated regional SPARROW (SPAtially Referenced Regressions On Watershed attributes) models covering most of the continental United States to evaluate the consistency and regional differences in factors affecting stream nutrient loads. The models – 6 for total nitrogen and 6 for total phosphorus – all provide similar levels of prediction accuracy, but those
Authors
Stephen D. Preston, Richard B. Alexander, Gregory E. Schwarz, Charles G. Crawford
A multi-agency nutrient dataset used to estimate loads, improve monitoring design, and calibrate regional nutrient SPARROW models
Stream‐loading information was compiled from federal, state, and local agencies, and selected universities as part of an effort to develop regional SPAtially Referenced Regressions On Watershed attributes (SPARROW) models to help describe the distribution, sources, and transport of nutrients in streams throughout much of the United States. After screening, 2,739 sites, sampled by 73 agencies, were
Authors
D. A. Saad, G. E. Schwarz, Dale M. Robertson, N.L. Booth
The Regionalization of National-Scale SPARROW Models for Stream Nutrients
This analysis modifies the parsimonious specification of recently published total nitrogen (TN) and total phosphorus (TP) national‐scale SPAtially Referenced Regressions On Watershed attributes models to allow each model coefficient to vary geographically among three major river basins of the conterminous United States. Regionalization of the national models reduces the standard errors in the pred
Authors
Gregory E. Schwarz, Richard B. Alexander, Richard A. Smith, Stephen D. Preston
The regionalization of national-scale SPARROW models for stream nutrients
This analysis modifies the parsimonious specification of recently published total nitrogen (TN) and total phosphorus (TP) national-scale SPAtially Referenced Regressions On Watershed attributes models to allow each model coefficient to vary geographically among three major river basins of the conterminous United States. Regionalization of the national models reduces the standard errors in the pred
Authors
Gregory E. Schwarz, Richard B. Alexander, Richard A. Smith, Stephen D. Preston
Sources of suspended-sediment flux in streams of the chesapeake bay watershed: A regional application of the sparrow model
We describe the sources and transport of fluvial suspended sediment in nontidal streams of the Chesapeake Bay watershed and vicinity. We applied SPAtially Referenced Regressions on Watershed attributes, which spatially correlates estimated mean annual flux of suspended sediment in nontidal streams with sources of suspended sediment and transport factors. According to our model, urban development g
Authors
J. W. Brakebill, S.W. Ator, G. E. Schwarz
Development of a national, dynamic reservoir-sedimentation database
The importance of dependable, long-term water supplies, coupled with the need to quantify rates of capacity loss of the Nation’s re servoirs due to sediment deposition, were the most compelling reasons for developing the REServoir- SEDimentation survey information (RESSED) database and website. Created under the auspices of the Advisory Committee on Water Information’s Subcommittee on Sedimenta io
Authors
J. R. Gray, J.M. Bernard, D. W. Stewart, E.J. McFaul, K.W. Laurent, G. E. Schwarz, J.T. Stinson, M.M. Jonas, T. J. Randle, J.W. Webb
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Filter Total Items: 67
Spatial variability in nutrient transport by HUC8, state, and subbasin based on Mississippi/Atchafalaya River Basin SPARROW models
Nitrogen (N) and phosphorus (P) loading from the Mississippi/Atchafalaya River Basin (MARB) has been linked to hypoxia in the Gulf of Mexico. With geospatial datasets for 2002, including inputs from wastewater treatment plants (WWTPs), and monitored loads throughout the MARB, SPAtially Referenced Regression On Watershed attributes (SPARROW) watershed models were constructed specifically for the MAAuthorsDale M. Robertson, David A. Saad, Gregory E. SchwarzSpatially explicit modeling to evaluate regional stream water quality
Spatially referenced regressions on watershed attributes (SPARROW) models have been developed and applied over the past two decades to address the need for large-scale, spatially explicit information on stream water quality conditions. The strength of SPARROW models is that they describe the primary environmental processes that affect the supply and transport of contaminant mass in watersheds, basAuthorsStephen D. Preston, Richard B. Alexander, Gregory Schwarz, Richard A. SmithEstimated nitrogen loads from selected tributaries in Connecticut draining to Long Island Sound, 1999–2009
The total nitrogen load to Long Island Sound from Connecticut and contributing areas to the north was estimated for October 1998 to September 2009. Discrete measurements of total nitrogen concentrations and continuous flow data from 37 water-quality monitoring stations in the Long Island Sound watershed were used to compute total annual nitrogen yields and loads. Total annual computed yields and bAuthorsJohn R. Mullaney, Gregory E. SchwarzRegional regression models of watershed suspended-sediment discharge for the eastern United States
Estimates of mean annual watershed sediment discharge, derived from long-term measurements of suspended-sediment concentration and streamflow, often are not available at locations of interest. The goal of this study was to develop multivariate regression models to enable prediction of mean annual suspended-sediment discharge from available basin characteristics useful for most ungaged river locatiAuthorsDavid C. Roman, Richard M. Vogel, Gregory E. SchwarzNutrient concentrations and loads in the northeastern United States - Status and trends, 1975-2003
The U.S. Geological Survey (USGS) National Water-Quality Assessment Program (NAWQA) began regional studies in 2003 to synthesize information on nutrient concentrations, trends, stream loads, and sources. In the northeastern United States, a study area that extends from Maine to central Virginia, nutrient data were evaluated for 130 USGS water-quality monitoring stations. Nutrient data were analyzeAuthorsElaine C. Todd Trench, Richard B. Moore, Elizabeth A. Ahearn, John R. Mullaney, R. Edward Hickman, Gregory E. SchwarzA multi-agency nutrient dataset used to estimate loads, improve monitoring design, and calibrate regional nutrient SPARROW models
Stream-loading information was compiled from federal, state, and local agencies, and selected universities as part of an effort to develop regional SPAtially Referenced Regressions On Watershed attributes (SPARROW) models to help describe the distribution, sources, and transport of nutrients in streams throughout much of the United States. After screening, 2,739 sites, sampled by 73 agencies, wereAuthorsDavid A. Saad, Gregory E. Schwarz, Dale M. Robertson, Nathaniel BoothFactors affecting stream nutrient loads: A synthesis of regional SPARROW model results for the continental United States
We compared the results of 12 recently calibrated regional SPARROW (SPAtially Referenced Regressions On Watershed attributes) models covering most of the continental United States to evaluate the consistency and regional differences in factors affecting stream nutrient loads. The models – 6 for total nitrogen and 6 for total phosphorus – all provide similar levels of prediction accuracy, but thoseAuthorsStephen D. Preston, Richard B. Alexander, Gregory E. Schwarz, Charles G. CrawfordA multi-agency nutrient dataset used to estimate loads, improve monitoring design, and calibrate regional nutrient SPARROW models
Stream‐loading information was compiled from federal, state, and local agencies, and selected universities as part of an effort to develop regional SPAtially Referenced Regressions On Watershed attributes (SPARROW) models to help describe the distribution, sources, and transport of nutrients in streams throughout much of the United States. After screening, 2,739 sites, sampled by 73 agencies, wereAuthorsD. A. Saad, G. E. Schwarz, Dale M. Robertson, N.L. BoothThe Regionalization of National-Scale SPARROW Models for Stream Nutrients
This analysis modifies the parsimonious specification of recently published total nitrogen (TN) and total phosphorus (TP) national‐scale SPAtially Referenced Regressions On Watershed attributes models to allow each model coefficient to vary geographically among three major river basins of the conterminous United States. Regionalization of the national models reduces the standard errors in the predAuthorsGregory E. Schwarz, Richard B. Alexander, Richard A. Smith, Stephen D. PrestonThe regionalization of national-scale SPARROW models for stream nutrients
This analysis modifies the parsimonious specification of recently published total nitrogen (TN) and total phosphorus (TP) national-scale SPAtially Referenced Regressions On Watershed attributes models to allow each model coefficient to vary geographically among three major river basins of the conterminous United States. Regionalization of the national models reduces the standard errors in the predAuthorsGregory E. Schwarz, Richard B. Alexander, Richard A. Smith, Stephen D. PrestonSources of suspended-sediment flux in streams of the chesapeake bay watershed: A regional application of the sparrow model
We describe the sources and transport of fluvial suspended sediment in nontidal streams of the Chesapeake Bay watershed and vicinity. We applied SPAtially Referenced Regressions on Watershed attributes, which spatially correlates estimated mean annual flux of suspended sediment in nontidal streams with sources of suspended sediment and transport factors. According to our model, urban development gAuthorsJ. W. Brakebill, S.W. Ator, G. E. SchwarzDevelopment of a national, dynamic reservoir-sedimentation database
The importance of dependable, long-term water supplies, coupled with the need to quantify rates of capacity loss of the Nation’s re servoirs due to sediment deposition, were the most compelling reasons for developing the REServoir- SEDimentation survey information (RESSED) database and website. Created under the auspices of the Advisory Committee on Water Information’s Subcommittee on Sedimenta ioAuthorsJ. R. Gray, J.M. Bernard, D. W. Stewart, E.J. McFaul, K.W. Laurent, G. E. Schwarz, J.T. Stinson, M.M. Jonas, T. J. Randle, J.W. Webb