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Author/Creator
- Geological Survey (U.S.)563
- National Water-Quality Assessment Program (U.S.)77
- United States. Environmental Protection Agency22
- United States. National Park Service15
- Arkansas Soil and Water Conservation Commission12
- United States. Bureau of Reclamation11
- Massachusetts. Department of Environmental Protection8
- Georgia. Environmental Protection Division7
- Pennsylvania. Department of Environmental Protection7
- United States. Bureau of Indian Affairs7
- United States. Forest Service7
- Wisconsin. Department of Natural Resources7
- Carter, Janet M.6
- Green, W. Reed6
- Heywood, Charles E.6
- Hopkins, Evelyn H.6
- Inman, Ernest J.6
- New Jersey. Department of Environmental Protection6
- South Dakota. Department of Environment and Natural Resources6
- South Florida Water Management District (Fla.)6