Dataset of SPARROW model input and predictions for total nitrogen and total phosphorus in North Carolina

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 point and nonpoint nutrient sources are recognized as major contributors of this degradation in rivers, lakes and estuaries. The SPARROW model was configured for North Carolina to predict total nitrogen and total phosphorus loads in streams and to evaluate the relative importance and contributions of nitrogen and phosphorus sources and other landscape characteristics. The model time period is 1999 to 2014, centered at 2012. This data release includes model input (data1_vTNTP.zip), model predictions (predict_TN.zip and predict_TP.zip) that represent simulated stream load, model catchment shapefile (model_catchments.zip), and a brief methodology (Methodology_TNTP.pdf). See the 'Methodology_TNTP.pdf' file for model documentation.