Maybe this information could be helpful. It has been several decades ago when we used BASINS for some of our watershed analysis on US and local National Forests, and I probably do not recall all the specifics. As I remember, EPA uploaded all their (including local, county, state and agency) georeferenced point and non-point pollution data and overlaid the basin and watershed boundary coverages such as those developed by the USGS as appropriate, so it could be interrogated for watershed type analysis or other uses as project planning or addressing water quality questions, classifications or uses. I would assume it to be a major work to expand elsewhere, but perhaps your resource agencies already have this information uploaded into their management or GIS data base, and might make it public for use, analysis and application. As I remember our use of BASINS involved more for qualitative watershed analysis condition and rating, and did not necessarily address quantitative analysis of water quality. Some locations are data rich, others lack quantitative specifics. I don’t remember if it included land use, but we also used that, as well as any specific information we had accumulated. I cannot remember the titles of a couple documents I put into Researchgate that likely used some of BASINS information, but one was Indian Creek Watershed Analysis, and another had to do with Watershed Analysis for National Forest Planning.

Thank you very much Sir William F. Hansen for the information.

@William F. Hansen