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David A Saad

Water ReUse Influences on Water Quality and Suitability
This Science Base page is for transfer of files related to the work of the Water Reuse Program. This location is to be used for transfering large files and spatial data among project members. Data posted here is data created by project members and not otherwise published or accessible elsewhere. These pages are orginized as Spatial (point covergaes, polygon shapefiles etc) and Tabular Data (NWIS pulls, Climate pulls, etc) as such: Code-> Python R Spatial Data-> Surface Water Ground Water Tabular Data-> Climate NWIS flow data Ag Census
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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 nutrient loads in streams across the Midwest 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...
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Nitrogen and phosphorus losses from agricultural areas have impacted the water quality of downstream rivers, lakes, and oceans. As a result, investment in the adoption of agricultural best management practices (BMPs) has grown but assessments of their effectiveness at large spatial scales have been sparse. This study applies regional Spatially Referenced Regression On Watershed-attributes (SPARROW) models developed for the Midwest, Northeast, and Southeast regions of the United States to quantify regional effects of BMPs on nutrient losses from agricultural lands. These models were used because they account for specific BMPs in the prediction of instream nutrient loads. This data release accompanies the journal...
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This USGS data release contains long-term mean annual total nitrogen and total phosphorus load estimates, and the model coefficients used to obtain the load estimates, for streams in the Midwest Region of the United States. The loads were estimated using the Fluxmaster program (Schwarz and others, 2006, https://pubs.usgs.gov/tm/2006/tm6b3) with a 5-parameter model and detrending to 2012 following the methods described in Saad and others, 2011 (https://doi.org/10.1111/j.1752-1688.2011.00575.x). A subset of these load estimates are described in Robertson and Saad, 2021 (https://doi.org/10.1111/1752-1688.12905) and were used to evaluate differences in load estimates in the Mississippi/Atchafalaya River Basin based...
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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 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 streamflow...
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