Washington State Department of EcologyAn instream flow rule is a flow regime set in state regulation. The legal authority to set instream flows by rule comes from laws passed by Washington State legislature, including:Construction projects in state waters (RCW 77.57.020) Water code (RCW 90.03.247)Minimum water flows and levels (Chapter 90.22 RCW)Water resources act of 1971 (Chapter 90.54 RCW, particularly section 020)Watershed planning (RCW 90.82.080)For background information and related links:https://ecology.wa.gov/Water-Shorelines/Water-supply/Protecting-stream-flowsFor information about specific areas:https://apps.leg.wa.gov/WAC/default.aspx?cite=173Title 173 WAC, 173-501 to 173-564For information about tribal land designations (reservation and trust) used in this dataset:https://fortress.wa.gov/ecy/gispublic/DataDownload/ECY_BND_TribalLands.htmArcGIS FeatureLayerhttps://hub.arcgis.com/datasets/cf9f21e92ffa48c0910fc9695ca003ad_2engState of Washington Geospatial Open Data PortalPublicInstream Flow Rules [Washington (State)]Web servicesWashington (State)Last Modified: 2025-12-26