This layer represents the eight mega-drainage basins for Massachusetts, aggregated from the Major Basins layer.
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This layer represents the eight mega-drainage basins for Massachusetts, aggregated from the Major Basins layer. The delineations were based on the level 2 (4-digit) Hydrologic Unit Codes (HUCs) from the U.S. Geological Survey. Included are delineation of the Narragansett and Thames mega-basins.
The HUC is a hierarchical, numeric code that uniquely identifies hydrologic units. Hydrologic units are subdivisions of watersheds nested from largest to smallest areas and are used to organize hydrologic data. In the 4-digit HUCs, the first two digits identify the region and the first four digits identify subregions.
The polygon layer is named MEGABASINS_POLY and the line layer MEGABASINS_ARC. Annotation is included in MEGABASINS_ANNO_BASIN.
AttributesThe polygon attribute table has the following items:
|NAME||Mega basin name (for informal use only - does not conform to USGS naming)|
MaintenanceMassGIS maintains the layer, although no updates are planned.
For other watershed data, see these layers:
- Major Watersheds (similar to 8-digit HUCs)
- Major Drainage Basins (similar to 8-digit HUCs)
- Drainage Sub-basins (more delineated than the 12-digit HUCs)
- NRCS HUC (8, 10, 12) Basins (8-, 10-, and 12-digit HUC delineations)
Last Updated 11/23/2005
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English (United States)