WRIA boundaries derived from terrain data

For 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.