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Subwatersheds

Published by D.C. Office of the Chief Technology Officer | District of Columbia | Metadata Last Checked: January 27, 2026 | Last Modified: 2002-03-01T00:00:00.000Z
This dataset is a complete digital hydrologic unit boundary layer to the subwatershed (12-digit) 6th level at 1:24,000 scale. This data set consists of geo-referenced digital data and associated attributes created in accordance with the FGDC Proposal, Version 1.0 - Federal Standards For Delineation of Hydrologic Unit Boundaries 3/01/02. The hydrologic unit boundaries provide a uniquely identified and uniform method of subdividing large drainage areas. Polygons are attributed with hydrologic unit codes, names, downstream hydrologic unit, flow modifications, and hydrologic unit type for 4th level (8-digit) sub-basin, 5th level (10-digit) watershed, 6th level (12-digit) subwatershed, and acres for subwatershed. An accompanying line shapefile is attributed with the highest hydrologic unit level for each hydrologic unit, line source, and a metadata reference file. 

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