DESCRIPTION
Salmon Creek, a tributary to the Okanogan River, is considered to be one of the most significant opportunities to restore summer steelhead in the Okanogan Basin. This project assists in the reconnection of the Okanogan River with approximately 11 miles of habitat conducive for spawning and rearing of summer steelhead.
The modification of an alluvial fan at the confluence of Salmon Creek and the Okanogan River and construction of a point bar directed the river flow toward the confluence to minimize sediment deposition that could impair steelhead access to Salmon Creek. The alluvial fan is primarily made up of unconsolidated bed load (gravel, cobble and rubble). This material was unstable and shifts during high flow conditions creating poor channel conditions for fish passage. Some grade control structures were installed to increase stability and prevent headcutting.
During controlled water releases in 2003, approximately 25 cfs was required for fish migration downstream of the diversion dam. During 2008 a 'low-flow' channel was constructed downstream of the diversion dam which provided suitable fish passage conditions at approximately 10 cfs. The low flow channel extended the duration of water available through a 12-year water lease program. Evaluation of the migration conditions and the stability of the low-flow channel will be conducted over the next several years. Minor modifications of the low-flow channel will be implemented concurrent with identification/evaluation.