Salmon Creek Water Rights Management

Client: Okanogan Irrigation District

Location: Okanogan, WA

Summary: ENTRIX worked as part of a team to develop an overall workable solution supported by the Colville Confederated Tribes (Tribes), the Okanogan Irrigation District (OID) and the community. The Tribes and the OID formed a joint committee to consider restoring anadromous salmonids to Salmon Creek in Washington. ENTRIX evaluated adult fish passage in the lower 4.2 miles of stream below the OID diversion using a controlled release study to collect empirical observations and hydraulic data to document surface flow losses to the subsurface. The lower portions of Salmon Creek have experience habitat degradation and channel instability due to over 80 years of irrigation diversions. ENTRIX worked with the irrigation systems engineers, water rights specialists, and stakeholder coordinator to develop and prioritize alternatives that achieve water supply and fisheries restoration goals. ENTRIX identified the magnitude, season and duration of flows necessary for adult salmonid up-migration, and the potential success of non-flow solutions, such as modification of channel geometry.