Hydrologic Soil Group Maps

[Jason Brown]

Using the NRCS Web Soil Survey, I can get hydrologic soil group maps with areas only up to 10,000 acres at a time. I have a 88+ square mile basin, and I need to know if there is another source or a way to use the NRCS maps where I can get seamless hydrologic soil group maps to use as an overaly with my land use maps to get CN values for my SCS analysis. Otherwise, i have to save many maps and the piece them together for an overall basin.

Thanks,

Jason

[Chris Maeder]

Soil type data types and sources are accessible via Internet from these sources (there may be others as well):

STATSGO
"State Soil Geographic Database", consolidated Soil Conservation Service soil maps at 1:250,000 scale. Not useful for small urban watersheds, but most appropriate for large projects. See STATSGO webpage for links to documentation and downloads:
U.S. General Soil Map (STATSGO) | NRCS NCGC

SSURGO
Detailed soil maps ("Soil Survey Geographic Database"). Usually electronic versions of county soil maps generated by SCS, 1160 datasets avaliable as of Spring 2002 out of 3066 counties in U.S. See SSURGO webpage at:
Soil Survey Geographic (SSURGO) Database | NRCS NCGC

EPA Surf Your Watershed
EPA has a watershed water quality research program, and data are meant to operate at the HUC level (unique Hydrologic Unit Code) at EPA's Surf Your Watershed:
Surf Your Watershed | Surf Your Watershed | US EPA

Hope that this helps.