Watershed Boundaries for the U.S. Geological Survey Southeast Stream Quality Assessment
Citation
Qi, S.L., Nakagaki, Naomi, Van Metre, P.C., Clark, J.M., Baker, N.T., Rapp, J.L., Falcone, J.A., Button, D.T., Journey, C.A., and Bell, A.H., 2017, Geospatial Database of the Study Boundary, Sampled Sites, Watersheds, and Riparian Zones for the U.S. Geological Survey Southeast Stream Quality Assessment: U.S. Geological Survey data release, https://doi.org/10.5066/F75Q4TKG.
Summary
In 2015, the second of several Regional Stream Quality Assessments (RSQA) was done in the southeastern United States. The Southeast Stream Quality Assessment (SESQA) was a study by the U.S. Geological Survey (USGS) National Water Quality Assessment (NAWQA) project. One of the objectives of the RSQA, and thus the SESQA, is to characterize the relationships between water-quality stressors and stream ecology and subsequently determine the relative effects of these stressors on aquatic biota within the streams (Van Metre and Journey, 2014). To meet this objective, a framework of fundamental geospatial data was required to develop physical and anthropogenic characteristics of the study region, sampled sites and corresponding watersheds, [...]
Summary
In 2015, the second of several Regional Stream Quality Assessments (RSQA) was done in the southeastern United States. The Southeast Stream Quality Assessment (SESQA) was a study by the U.S. Geological Survey (USGS) National Water Quality Assessment (NAWQA) project. One of the objectives of the RSQA, and thus the SESQA, is to characterize the relationships between water-quality stressors and stream ecology and subsequently determine the relative effects of these stressors on aquatic biota within the streams (Van Metre and Journey, 2014). To meet this objective, a framework of fundamental geospatial data was required to develop physical and anthropogenic characteristics of the study region, sampled sites and corresponding watersheds, and riparian zones. This dataset represents the 115 water-chemistry sites sampled for the SESQA, and is one of the four fundamental geospatial data layers that were developed for the Southeast study.
The SESQA watershed boundaries were delineated using the following four data sources listed in order of precedence: 1) the Watershed Boundary Dataset (WBD) (U.S. Department of Agriculture, 2013); 2) StreamStats (U.S. Geological Survey, 2012); 3) the National Hydrography Dataset Plus Version 2.1, or "NHDPlusV2" (U.S. Environmental Protection Agency and U.S. Geological Survey, 2012); and 4) 1:24,000-scale U.S. Geological Survey (USGS) topographic maps (U.S. Geological Survey and National Geographic Society, 2013). Initially (for site selection), preliminary watershed boundaries were quickly developed from the NHDPlusV2 dataset and StreamStats, in states where StreamStats was fully implemented (AL, GA, and NC). For the finalized watershed boundaries, the WBD line segments that closely followed the draft watershed boundaries were duplicated in the SESQA watershed boundaries. This step was required since linework from StreamStats is generated from rasters and appears "stair stepped" and, since the linework for final watershed delineations is required by the USGS to follow the WBD boundaries when appropriate, the WBD linework that closely followed the StreamStats linework were selected to be part of the final watershed boundaries. To complete the delineation from the copied WBD linework to any given water-chemistry sampling site, relevant line segments were copied from the preliminary watershed delineation developed using StreamStats (U.S. Geological Survey, 2012) if it was available; otherwise, line segments were copied from the preliminary watershed boundary delineated from NHDPlusV2 (U.S. Environmental Protection Agency and U.S. Geological Survey, 2012). In some cases, the watershed boundary was further refined (hand digitized) near the sampling site using contour data from USGS topographic maps (U.S. Geological Survey and National Geographic Society, 2013). For Va and SC, states where StreamStats was not implemented at the time (December, 2014), basins were digitized: basin linework from Jimmy M. Clark (USGS, written commun., 2014) and Jennifer Krstolic (USGS, written commun., 2014; Krstolic, 2006) were used. Linework from Clark was derived using an automated process in ArcMap and 10-meter resolution digital elevation model (DEM) rasters (U.S. Geological Survey, 2009), using the ArcGIS tools (Esri, 2014), in order, Flow Direction, Flow Accumulation, Fill, and Watershed. Please see USGS Open-File Report 2006-1308 (Krstolic, 2006) for details about how that linework was derived.
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SESQAWatersheds.xml Original FGDC Metadata
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SESQAWatersheds.zip
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Purpose
This dataset was created to compile environmental characteristics of the sites sampled for SESQA. The site characteristics assist with the analysis and interpretation of surface-water and biota data collected for the SESQA study, and were also used as input into various models.
