King County Dept. of Natural Resources and Parks, Water and Lands Resources DivisionFor more information about this layer please see the GIS Data Catalog . Watershed Resource Inventory Area. WRIA planning units were established under Washington Administrative Code (WAC 173-500). Planning and implementation of environmental stewardships are codified in Revised Code of Washington State (RCW 90.82). WRIAs are generally delineated to capture large watersheds in Washington State. For example WRIA 9 includes The Green/Duwamish River basins and Puget sound nearshores west of the watershed. WRIA 8 include the Greater Lake Washington watershed and it's adjacent Puget sound nearshore lands. Hence they are a composite of watershed drainage areas that include a river basin(s) and also small tributary areas that directly drain to the Puget sound. These WRIA boundaries were revised using digital elevation models.ArcGIS FeatureLayerhttps://hub.arcgis.com/datasets/db381f06b2724eb4a87bc6c51a0cee08_0engKing County GIS Open DataPublicWRIA boundaries derived from terrain data [Washington (State)--King County]Web servicesWashington (State)--King CountyWashington (State)Last Modified: 2026-04-01