The Upper Yakima River below Kachess and Keechelus Dams is a regulated river that undergoes a “flip-flop” flow regime where irrigation return flows increase during normally low water summer months and decrease flows during normally high water winter months to fill the reservoirs. Development and flow regulation have dramatically reduced refugia for endangered salmon in the Upper Yakima River. NSD + CGS was contracted with the YN to help restore habitat complexity along the Cle Elum Reach of the mainstem Yakima River. Design elements address river fluvial dynamics and local concerns for recreational safety around ELJ habitat, utilizing design and installation of pile supported logjam structures in a large river system. Washington Department of Natural Resources (DNR) representatives expressed concern about safety risks, geomorphic response, and potential downstream liability associated with the project. NSD + CGS addressed the safety risk and designed optimal ELJ edge habitat for juvenile salmonids, with the intent to increase rearing habitat in this compromised reach.
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