Stream Type

For more information about this layer please see the GIS Data Catalog. Stream Type is a watercourse layer that identifies the regulatory stream type per the County’s definitions in the Critical Areas Ordinance. The baseline data for the physical stream location comes from the Coho Intrinsic Potential stream layer, which was based on the county’s ‘watercourse’ layer circa 2020. The 4 types of stream are: S -Shoreline of the state, F - Fish bearing or has fish habitat, and N - Non-fish bearing, and O- Other. Currently many smaller streams do not have enough data to be classified as a particular stream type without a field survey. If the classification is unknown, the classification is left blank. Shoreline jurisdiction is defined by Washington Department of Ecology and the County’s Shoreline Master Plan. Fish observations, fish use based on physical channel measurements, and presumed fish use data come from multiple sources, including King County, WRIA fish distribution maps, Wild Fish Conservancy, and the Statewide Washington Fish Wide Distribution (SWIFD) datasets. Stream type attribution is based on a hierarchical scheme whereby shoreline and fish observations are populated first, followed by F type designations based on physical channel measurements versus documented fish observations and finally, presumed use. The Stream Type field is not fish species specific, but there are separate fields for the species listed on the Endangered Species Act list- Chinook salmon, steelhead trout, and bull trout or dolly varden. These fish species fields are populated based on documented observations, and a blank value does not necessarily indicate that the species would not use the stream reach.