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The WA State National Hydrography Dataset (NHD) is the standard hydrography for Washington. NHD Area along with WA NHD Waterbody represent the polygon water features. NHD Flowline contains the linear watercourses. The most important NHD Area features are Sea Ocean, double banked StreamRiver, and BayInlet polygonsNHDWaterbody types and their corresponding FType Codes are Estuary(493), LakePond(390), SwampMarsh(466), Constructed Reservoir(436), Ice Mass(378), and Playa(361). NHD Flowline linear watercourses include streams, rivers, canals, ditches, coastline, pipelines, and artificial paths (centerlines through water polygon features such as lakes, estuaries, or double-banked streams). Washington State Hydrography Standard (OCIO policy 161.03). Hydrography data for Washington are developed at a resolution of 1:4,800 to 1:24,000. This dataset was extracted from the USGS in March 2019 and projected into WA State Plane Coordinates South. The National Hydrography Dataset (NHD) is a feature-based database that interconnects and uniquely identifies the stream segments or reaches that make up the nation's surface water drainage system. This high-resolution NHD, generally is developed at 1:24,000/1:12,000 scale, but many areas of Washington State have been improved to 1:4800 scale. NHD data was originally developed at 1:100,000-scale and exists at that scale for the whole country. Local resolution NHD is being developed where partners and data exist. The NHD contains reach codes for networked features, flow direction, names, and centerline representations for areal water bodies. Reaches are also defined on waterbodies and the approximate shorelines of the Great Lakes, the Atlantic and Pacific Oceans and the Gulf of Mexico. The NHD also incorporates the National Spatial Data Infrastructure framework criteria established by the Federal Geographic Data CommitteeA detailed data dictionary is available at https://nhd.usgs.gov/userguide.html?url=NHD_User_Guide/Feature_Catalog/NHD_Feature_Catalog.htm |