Gregory E Schwarz (Former Employee)
Science and Products
Select Attributes for NHDPlus Version 2.1 Reach Catchments and Modified Network Routed Upstream Watersheds for the Conterminous United States (ver. 5.0, June 2025) Select Attributes for NHDPlus Version 2.1 Reach Catchments and Modified Network Routed Upstream Watersheds for the Conterminous United States (ver. 5.0, June 2025)
This metadata record describes a series of data sets of natural and anthropogenic landscape features linked to NHDPlus Version 2.1’s (NHDPlusV2) approximately 2.7 million stream segments, their associated catchments, and their upstream watersheds within the conterminous United States. The data were linked to four spatial components of NHDPlusV2: individual reach catchments, riparian...
Water-quality and streamflow datasets used for estimating long-term mean daily streamflow and annual loads to be considered for use in regional streamflow, nutrient and sediment SPARROW models, United States, 1999-2014 Water-quality and streamflow datasets used for estimating long-term mean daily streamflow and annual loads to be considered for use in regional streamflow, nutrient and sediment SPARROW models, United States, 1999-2014
The United States Geological Survey's (USGS) SPAtially Referenced Regressions On Watershed attributes (SPARROW) model was developed to aid in the interpretation of monitoring data and simulate water-quality conditions in streams across large spatial scales. SPARROW is a hybrid empirical/process-based mass balance model that can be used to estimate the major sources and environmental...
Inputs and Selected Predictions of the CBTN_v5 and CBTP_v5 SPARROW Models for the Chesapeake Bay Watershed Inputs and Selected Predictions of the CBTN_v5 and CBTP_v5 SPARROW Models for the Chesapeake Bay Watershed
The CBTN_v5 and CBTP_v5 SPARROW models were developed to support inferences about causes of observed changes in nitrogen and phosphorus (respectively) fluxes in Chesapeake Bay tributaries between 1992 and 2012. Model inputs and outputs are included in three files, which are described below. Detailed documentation of the SPARROW modeling technique is available at https://pubs.er.usgs.gov
Database of modified routing for NHDPlus version 2.1 flowlines: ENHDPlusV2_us Database of modified routing for NHDPlus version 2.1 flowlines: ENHDPlusV2_us
This database (ENHDPlusV2_us) contains a topologically reconditioned (enhanced) version of the U.S. Environmental Protection Agency (USEPA) and the U.S. Geological Survey (USGS) NHDPlus Version 2.1 (NHDPlusV2) flowline network. The comma separated file included in this release contains routing and stream connection information, with the intention of improving accuracy and networking...
Filter Total Items: 68
Instruments, methods, rationale, and derived data used to quantify and compare the trapping efficiencies of four types of pressure-difference bedload samplers Instruments, methods, rationale, and derived data used to quantify and compare the trapping efficiencies of four types of pressure-difference bedload samplers
Bedload and ancillary data were collected to calculate and compare the bedload trapping efficiencies of four types of pressure-difference bedload samplers as part of episodic, sediment-recirculating flume experiments at the St. Anthony Falls Laboratory, University of Minnesota, Minneapolis, in January–March 2006. The bedload-sampler experiments, which were conceived, organized, and led...
Authors
John R. Gray, Gregory E. Schwarz, David J. Dean, Jonathan A. Czuba, Joel T. Groten
Accounting for temporal variability of streamflow in estimates of travel time Accounting for temporal variability of streamflow in estimates of travel time
Retention, processing, and transport of solutes and particulates in stream corridors are influenced by the travel time of streamflow through stream channels, which varies dynamically with discharge. The effects of streamflow variability across sites and over time cannot be addressed by time-averaged models if parameters are based solely on the characteristics of mean streamflow. We...
Authors
Christopher P. Konrad, Noah Schmadel, Judson Harvey, Gregory E. Schwarz, Jesus Gomez-Velez, Elizabeth W. Boyer, Durelle Scott
Low threshold for nitrogen concentration saturation in headwaters increases regional and coastal delivery Low threshold for nitrogen concentration saturation in headwaters increases regional and coastal delivery
River corridors store, convey, and process nutrients from terrestrial and upstream sources, regulating delivery from headwaters to estuaries. A consequence of chronic excess nitrogen loading, as supported by theory and field studies in specific areas, is saturation of the biogeochemically-mediated nitrogen removal processes that weakens the capacity of the river corridor to remove...
Authors
Noah Schmadel, Judson Harvey, Richard Alexander, Elizabeth W. Boyer, Gregory E. Schwarz, Jesus D. Gomez-Velez, Durelle Scott, Christopher Konrad
An enhanced hydrologic stream network based on the NHDPlus medium resolution dataset An enhanced hydrologic stream network based on the NHDPlus medium resolution dataset
The National Hydrography Dataset Plus, Version 2.1 (NHDPlusV2.1) is an attribute-rich digital stream network for the conterminous United States, serving as a foundational infrastructure for reporting hydrologic information at both regional and national scales. SPAtially Referenced Regressions On Watershed attributes (SPARROW) is a process-based statistical model that relies on a digital...
Authors
John W. Brakebill, Gregory E. Schwarz, Michael E. Wieczorek
Advances in quantifying streamflow variability across continental scales: 2. Improved model regionalization and prediction uncertainties using hierarchical Bayesian methods Advances in quantifying streamflow variability across continental scales: 2. Improved model regionalization and prediction uncertainties using hierarchical Bayesian methods
The precise estimation of process effects in hydrological models requires applying models to large scales with extensive spatial variability in controlling factors. Despite progress in large‐scale applications of hydrological models in conterminous United States (CONUS) river basins, spatial constraints in model parameters have prevented the interbasin sharing of data, complicating...
Authors
Richard B. Alexander, Gregory E. Schwarz, Elizabeth W. Boyer
Phosphorus and nitrogen transport in the binational Great Lakes Basin estimated using SPARROW watershed models Phosphorus and nitrogen transport in the binational Great Lakes Basin estimated using SPARROW watershed models
Eutrophication problems in the Great Lakes are caused by excessive nutrient inputs (primarily phosphorus, P, and nitrogen, N) from various sources throughout its basin. In developing protection and restoration plans, it is important to know where and from what sources the nutrients originate. As part of a binational effort, Midcontinent SPARROW (SPAtially Referenced Regression On...
Authors
Dale M. Robertson, David A. Saad, Glenn A. Benoy, Ivana Vouk, Gregory E. Schwarz, Michael T Laitta
Science and Products
Select Attributes for NHDPlus Version 2.1 Reach Catchments and Modified Network Routed Upstream Watersheds for the Conterminous United States (ver. 5.0, June 2025) Select Attributes for NHDPlus Version 2.1 Reach Catchments and Modified Network Routed Upstream Watersheds for the Conterminous United States (ver. 5.0, June 2025)
This metadata record describes a series of data sets of natural and anthropogenic landscape features linked to NHDPlus Version 2.1’s (NHDPlusV2) approximately 2.7 million stream segments, their associated catchments, and their upstream watersheds within the conterminous United States. The data were linked to four spatial components of NHDPlusV2: individual reach catchments, riparian...
Water-quality and streamflow datasets used for estimating long-term mean daily streamflow and annual loads to be considered for use in regional streamflow, nutrient and sediment SPARROW models, United States, 1999-2014 Water-quality and streamflow datasets used for estimating long-term mean daily streamflow and annual loads to be considered for use in regional streamflow, nutrient and sediment SPARROW models, United States, 1999-2014
The United States Geological Survey's (USGS) SPAtially Referenced Regressions On Watershed attributes (SPARROW) model was developed to aid in the interpretation of monitoring data and simulate water-quality conditions in streams across large spatial scales. SPARROW is a hybrid empirical/process-based mass balance model that can be used to estimate the major sources and environmental...
Inputs and Selected Predictions of the CBTN_v5 and CBTP_v5 SPARROW Models for the Chesapeake Bay Watershed Inputs and Selected Predictions of the CBTN_v5 and CBTP_v5 SPARROW Models for the Chesapeake Bay Watershed
The CBTN_v5 and CBTP_v5 SPARROW models were developed to support inferences about causes of observed changes in nitrogen and phosphorus (respectively) fluxes in Chesapeake Bay tributaries between 1992 and 2012. Model inputs and outputs are included in three files, which are described below. Detailed documentation of the SPARROW modeling technique is available at https://pubs.er.usgs.gov
Database of modified routing for NHDPlus version 2.1 flowlines: ENHDPlusV2_us Database of modified routing for NHDPlus version 2.1 flowlines: ENHDPlusV2_us
This database (ENHDPlusV2_us) contains a topologically reconditioned (enhanced) version of the U.S. Environmental Protection Agency (USEPA) and the U.S. Geological Survey (USGS) NHDPlus Version 2.1 (NHDPlusV2) flowline network. The comma separated file included in this release contains routing and stream connection information, with the intention of improving accuracy and networking...
Filter Total Items: 68
Instruments, methods, rationale, and derived data used to quantify and compare the trapping efficiencies of four types of pressure-difference bedload samplers Instruments, methods, rationale, and derived data used to quantify and compare the trapping efficiencies of four types of pressure-difference bedload samplers
Bedload and ancillary data were collected to calculate and compare the bedload trapping efficiencies of four types of pressure-difference bedload samplers as part of episodic, sediment-recirculating flume experiments at the St. Anthony Falls Laboratory, University of Minnesota, Minneapolis, in January–March 2006. The bedload-sampler experiments, which were conceived, organized, and led...
Authors
John R. Gray, Gregory E. Schwarz, David J. Dean, Jonathan A. Czuba, Joel T. Groten
Accounting for temporal variability of streamflow in estimates of travel time Accounting for temporal variability of streamflow in estimates of travel time
Retention, processing, and transport of solutes and particulates in stream corridors are influenced by the travel time of streamflow through stream channels, which varies dynamically with discharge. The effects of streamflow variability across sites and over time cannot be addressed by time-averaged models if parameters are based solely on the characteristics of mean streamflow. We...
Authors
Christopher P. Konrad, Noah Schmadel, Judson Harvey, Gregory E. Schwarz, Jesus Gomez-Velez, Elizabeth W. Boyer, Durelle Scott
Low threshold for nitrogen concentration saturation in headwaters increases regional and coastal delivery Low threshold for nitrogen concentration saturation in headwaters increases regional and coastal delivery
River corridors store, convey, and process nutrients from terrestrial and upstream sources, regulating delivery from headwaters to estuaries. A consequence of chronic excess nitrogen loading, as supported by theory and field studies in specific areas, is saturation of the biogeochemically-mediated nitrogen removal processes that weakens the capacity of the river corridor to remove...
Authors
Noah Schmadel, Judson Harvey, Richard Alexander, Elizabeth W. Boyer, Gregory E. Schwarz, Jesus D. Gomez-Velez, Durelle Scott, Christopher Konrad
An enhanced hydrologic stream network based on the NHDPlus medium resolution dataset An enhanced hydrologic stream network based on the NHDPlus medium resolution dataset
The National Hydrography Dataset Plus, Version 2.1 (NHDPlusV2.1) is an attribute-rich digital stream network for the conterminous United States, serving as a foundational infrastructure for reporting hydrologic information at both regional and national scales. SPAtially Referenced Regressions On Watershed attributes (SPARROW) is a process-based statistical model that relies on a digital...
Authors
John W. Brakebill, Gregory E. Schwarz, Michael E. Wieczorek
Advances in quantifying streamflow variability across continental scales: 2. Improved model regionalization and prediction uncertainties using hierarchical Bayesian methods Advances in quantifying streamflow variability across continental scales: 2. Improved model regionalization and prediction uncertainties using hierarchical Bayesian methods
The precise estimation of process effects in hydrological models requires applying models to large scales with extensive spatial variability in controlling factors. Despite progress in large‐scale applications of hydrological models in conterminous United States (CONUS) river basins, spatial constraints in model parameters have prevented the interbasin sharing of data, complicating...
Authors
Richard B. Alexander, Gregory E. Schwarz, Elizabeth W. Boyer
Phosphorus and nitrogen transport in the binational Great Lakes Basin estimated using SPARROW watershed models Phosphorus and nitrogen transport in the binational Great Lakes Basin estimated using SPARROW watershed models
Eutrophication problems in the Great Lakes are caused by excessive nutrient inputs (primarily phosphorus, P, and nitrogen, N) from various sources throughout its basin. In developing protection and restoration plans, it is important to know where and from what sources the nutrients originate. As part of a binational effort, Midcontinent SPARROW (SPAtially Referenced Regression On...
Authors
Dale M. Robertson, David A. Saad, Glenn A. Benoy, Ivana Vouk, Gregory E. Schwarz, Michael T Laitta