To better understand the influence of human activities and natural processes on surface-water quality, the U.S. Geological Survey (USGS) developed the SPARROW (SPAtially Referenced Regressions On Watershed attributes) (Schwarz and others, 2006; Alexander and others, 2008) model. The framework is used to relate water-quality monitoring data to sources and watershed characteristics that affect the fate and transport of constituents to receiving surface-water bodies. The core of the model consists of using a nonlinear-regression equation to describe the non-conservative transport of contaminants from point and nonpoint sources on land to rivers, lakes and estuaries through the stream and river network. In North Carolina, excessive sediment loadings have contributed to the degradation of surface-water quality, and riverine and upland sediment sources are recognized as major contributors of this degradation in rivers, lakes and estuaries. The SPARROW model was configured for North Carolina to predict sediment loads in streams and to evaluate the relative importance of sediment sources and other landscape characteristics. The model time period is 1999 to 2014 and centered at 2012. This data release includes model input (data1_vTSS.zip), model predictions (predict_TSS.zip) that represent simulated stream load, model catchment shapefile (model_catchments.zip), and a brief methodology (Methodology_TSS.pdf). See the 'Methodology_TSS.pdf' file for model documentation.

The U.S. Geological Survey's (USGS) SPAtially Referenced Regressions On Watershed attributes (SPARROW version 2_10) model was used to aid in the interpretation of monitoring data and simulate streamflow and water-quality conditions in streams across the Pacific Region of the Unites States. SPARROW is a hybrid empirical/process-based mass balance model that can be used to estimate the major sources and environmental factors that affect the long-term supply, transport, and fate of contaminants in streams. The spatially explicit model structure is defined by a river reach network coupled with contributing catchments. The model is calibrated by statistically relating watershed sources and transport-related properties to monitoring-based water-quality load estimates. This USGS data release includes input and output files associated with 2012 SPARROW simulations of streamflow, total nitrogen, total phosphorus and suspended sediment load in streams of the Pacific region. Model construction, calibration and results are described in Wise (2019, https://doi.org/10.3133/sir20195112). First posted - January 6, 2020(available from author) Revised - June 08, 2020

The U.S. Geological Survey's (USGS) SPAtially Referenced Regression On Watershed attributes (SPARROW) model was used to aid in the interpretation of monitoring data and simulate streamflow and water-quality conditions in streams across the Southeast Region of the United States. SPARROW is a hybrid empirical/process-based mass balance model that can be used to estimate the major sources and environmental factors that affect the long-term supply, transport, and fate of contaminants in streams. The spatially explicit model structure is defined by a river reach network coupled with contributing catchments. The model is calibrated by statistically relating watershed sources and transport-related properties to monitoring-based water-quality load estimates. This USGS data release includes input and output files associated with 2012 SPARROW simulations of streamflow, total nitrogen, total phosphorus and suspended-sediment load in streams of the Southeast region. Model construction, calibration and results are described in Hoos and Roland (2019, https://doi.org/10.3133/sir20195135).

The U.S. Geological Survey's (USGS) SPAtially Referenced Regression On Watershed attributes (SPARROW) model was used to aid in the interpretation of monitoring data and simulate streamflow and water-quality conditions in streams across the Southeast Region of the United States. SPARROW is a hybrid empirical/process-based mass balance model that can be used to estimate the major sources and environmental factors that affect the long-term supply, transport, and fate of contaminants in streams. The spatially explicit model structure is defined by a river reach network coupled with contributing catchments. The model is calibrated by statistically relating watershed sources and transport-related properties to monitoring-based water-quality load estimates. This USGS data release includes input and output files associated with 2012 SPARROW simulations of streamflow, total nitrogen, total phosphorus and suspended-sediment load in streams of the Southeast region. Model construction, calibration and results are described in Hoos and Roland (2019, https://doi.org/10.3133/sir20195135).

The U.S. Geological Survey’s (USGS) SPAtially Referenced Regression On Watershed attributes (SPARROW) model was developed to aid in the interpretation of monitoring data and simulate water-quality conditions in streams across the Midcontinental Region of Canada and the Unites States. SPARROW is a hybrid empirical⁄process-based mass balance model that can be used to estimate the major sources and environmental factors that affect the long-term supply, transport, and fate of contaminants in streams. The spatially explicit model structure is defined by a river reach network coupled with contributing catchments. The model is calibrated by statistically relating watershed sources and transport-related properties to monitoring-based water-quality load estimates. This USGS data release, prepared in cooperation with the International Joint Commission and National Research Council Canada, includes output files representing 2002 SPARROW simulations of total nitrogen and total phosphorus in streams of the Midcontinent. Model calibration and results are described in Robertson and others (2019, https://doi.org/10.1111/1752-1688.12792). Geospatial data used for developing the Midcontinental SPARROW nutrient models are described in Vouk and others (2018, https://doi.org/10.4224/23004810). Model calibration targets used in the SPARROW models are described in Saad and others (2018, https://doi.org/10.3133/sir20185051).

These data represent both inputs for and estimates from a medium-resolution (1:100,000 scale) NHDPlus SPAtially Referenced Regression on Watershed attributes (SPARROW) model for the Chesapeake Bay watershed (CBSS_v2). The model spatially correlates long-term mean annual suspended-sediment flux in 113 non-tidal streams to likely upland and stream-corridor sources, landscape factors affecting upland sediment transport and delivery to stream corridors, and fluvial and reservoir retention representing the early 2000 time period. The item COMID is a common related field between the data file and the spatial component (catchments) in NHDPlus version 1.0.

The U.S. Geological Survey's (USGS) SPAtially Referenced Regression On Watershed attributes (SPARROW) model was used to aid in the interpretation of monitoring data and simulate streamflow and water-quality conditions in streams across the Northeast Region of the United States. SPARROW is a hybrid empirical/process-based mass balance model that can be used to estimate the major sources and environmental factors that affect the long-term supply, transport, and fate of contaminants in streams. The spatially explicit model structure is defined by a river reach network coupled with contributing catchments. The model is calibrated by statistically relating watershed sources and transport-related properties to monitoring-based water-quality load estimates. This USGS data release includes input and output files associated with 2012 SPARROW simulations of streamflow, total nitrogen, total phosphorus and suspended-sediment load in streams of the Northeast region. Model construction, calibration and results are described in Ator (2019, https://doi.org/10.3133/sir20195118).

The U.S. Geological Survey’s SPAtially Referenced Regression On Watershed attributes (SPARROW) for the Southeastern United States was used to simulate changes in total nitrogen, total phosphorus and suspended sediment load in streams under two scenarios: (1) where all forests are urbanized and (2) where all forests are urbanized and runoff is adjusted based on a non-forested landscape. This data release includes model input not published with the original model and used for scenario simulations, and model output for total nitrogen, total phosphorus, and suspended sediment under baseline conditions, scenario (1), and scenario (2). Original model input, output, and shapefiles are available (Roland and Hoos, 2020, https://https://doi.org/10.5066/p9a682gw) and original model development is described in Hoos and Roland (2019, https://doi.org/10.3133/sir20195135).

The U.S. Geological Survey's (USGS) SPAtially Referenced Regression On Watershed attributes (SPARROW) model was used to aid in the interpretation of monitoring data and simulate streamflow and water-quality conditions in streams across the Southwestern Region of the Unites States. SPARROW is a hybrid empirical/process-based mass balance model that can be used to estimate the major sources and environmental factors that affect the long-term supply, transport, and fate of contaminants in streams. The spatially explicit model structure is defined by a river reach network coupled with contributing catchments. The model is calibrated by statistically relating watershed sources and transport-related properties to monitoring-based water-quality load estimates. This USGS data release includes input and output files associated with 2012 SPARROW simulations of streamflow, total nitrogen, total phosphorus and suspended-sediment load in streams of the Southwestern region. Model construction, calibration and results are described in Wise, Anning, and Miller (2019, https://doi.org/10.3133/sir20195106.

The U.S. Geological Survey's (USGS) SPAtially Referenced Regression On Watershed attributes (SPARROW) model was used to aid in the interpretation of monitoring data and simulate streamflow and water-quality conditions in streams across the Southwestern Region of the Unites States. SPARROW is a hybrid empirical/process-based mass balance model that can be used to estimate the major sources and environmental factors that affect the long-term supply, transport, and fate of contaminants in streams. The spatially explicit model structure is defined by a river reach network coupled with contributing catchments. The model is calibrated by statistically relating watershed sources and transport-related properties to monitoring-based water-quality load estimates. This USGS data release includes input and output files associated with 2012 SPARROW simulations of streamflow, total nitrogen, total phosphorus and suspended-sediment load in streams of the Southwestern region. Model construction, calibration and results are described in Wise, Anning, and Miller (2019, https://doi.org/10.3133/sir20195106.