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Federal
National Hydrography Dataset (NHD) - USGS National Map Downloadable Data Collection NGDA
Department of the Interior —
The National Hydrography Dataset (NHD) is a feature-based database that interconnects and uniquely identifies the stream segments or reaches that make up the nation's... -
Federal
Base-flow index grid for the conterminous United States
Department of the Interior —
This 1-kilometer raster (grid) dataset for the conterminous United States was created by i nterpolating base-flow index (BFI) values estimated at U.S. Geological...