Driscoll Island Cold Water Refuge Design 

This project presented an opportunity to design cold water off-channel refuge for juvenile salmonids using relic channels that existed historically but are now either silted in or levied off from the river. These channels would be available during a critical time of year when water temperatures in the main-stem Okanogan and Similkameen Rivers bordering Driscoll Island are not favorable to salmonid growth and survival. High temperatures currently drive these fish to less favorable habitats, and can result in mortality.  Water temperature strongly influences the composition of aquatic communities with salmonids thriving or surviving only within a limited temperature range. Physiological functions are commonly influenced by temperature, while some behaviors are linked to temperature, and temperature is closely associated with many life cycle changes. Temperature indirectly influences oxygen solubility, nutrient availability, and the decomposition of organic matter; all of which affect the structure and function of biotic communities and the health of the fish within them. As water warms, oxygen and nutrient availability decrease.

Our objective in this project is to collect appropriate data to inform alternatives, and investigate the feasibility of using on-sight ground water to construct off-stream channels to allow juvenile salmonids a safe habitat.

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Partners: Colville Confederated Tribe and WDFW.

Funding provided by the Salmon Recovery Funding Board (SRFB).

Project Completed: June 2013