CAUSES for listing a waterbody on the US EPA's 303d list by HUC 10 watershed

This dataset sums the CAUSES for listing a waterbody on the US EPA's 303d list by HUC 10 watershed. The line (streams) and polygon (ponds, lakes, reservoirs, etc.) GIS was obtained from the California State Water Quality Control Board and contains all streams listed on the 303d list. These GIS layers were joined to a table (also from the California State Water Quality Control Board) that lists all impaired water bodies, the pollutant for which they are listed, and the potential CAUSE of that pollutant in a water body. For this dataset, the CAUSE(S) for each water body were used to assess the level of impairment by HUC10 watershed. It was assumed that more causes per watershed implied a higher level of impairment.