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Federal
Hydrologic landscape regions of the United States
Department of the Interior —
Hydrologic landscape regions (HLRs) in the United States were delineated by using geographic information system (GIS) tools and statistical methods including... -
Federal
Attributes for NHDPlus Catchments (Version 1.1)for the Conterminous United States: Contact Time, 2002
Department of the Interior —
This data set represents the average contact time, in units of days, compiled for every catchment of NHDPlus for the conterminous United States. Contact time, as... -
Federal
Digital data set describing surficial geology in the conterminous US
Department of the Interior —
This digital data set describes surficial geology of the conterminous United States. The data set was generated from a U.S. Geological Survey 1:7,500,000-scale map of...