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Ana Maria Garcia

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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,...
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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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As part of the Coastal Carolinas Focus Area Study of the U.S. Geological Survey National Water Census Program, the Soil and Water Assessment Tool (SWAT) was used to develop models for the Pee Dee River Basin, North Carolina and South Carolina, to simulate future streamflow and irrigation demand based on land use, climate, and water demand projections. SWAT is a basin-scale, process-based watershed model with the capability of simulating water-management scenarios. Model basins were divided into approximately two-square mile subbasins and subsequently divided into smaller, discrete hydrologic response units based on land use, slope, and soil type. The calibration period for the historic model was 2000 to 2014. The...
Types: Map Service, OGC WFS Layer, OGC WMS Layer, OGC WMS Service; Tags: Alexander, Alleghany, Anson, Ashe, Bladen, All tags...
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Alterations to stream hydrology, which include changes in stream geomorphology, are primary impacts of anthropogenic disruption. In North Carolina, hydrological alterations lead to environmental impacts through degraded ecosystems and water quality. In collaboration with the North Carolina Department of Environmental Quality, Division of Mitigation Services (DMS), the USGS South Atlantic Water Science Center datasets are proxy measurements of the extent of altered hydrology in riverine systems across the State of North Carolina. The datasets consist of an inventory and characterization of small scale (mostly agricultural) ponds and artificial drainages, which are both significant hydrologic modifications in the...
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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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