DESCRIPTION
Yakima County used this RCO Salmon Recovery Funding Board (SRFB) grant to enhance flood conveyance, encourage channel migration, and make sediment more available at two nearby sites in the Yakima River so that natural channel/habitat forming processes can initiate and create much more diverse channel and floodplain habitats for salmonids. At Sportsman Island, the County excavated ~1000 ft of new left bank side channel through a point bar that was elevated above the water surface of the Yakima River. The excavation enhanced the river's connection to existing side channels so that a total of about 1 mile of improved side channel connection was achieved. The original proposal also called for side channel excavation on an upstream right bank point bar, just below the Terrace Heights bridge. However, this project element became unnecessary when the river naturally began to form channels through the area. This reduction in work scope reduced the overall project cost. Although the County only worked on the left bank, they still achieved the 1 mile of side channel connection that had been estimated at application; the County underestimated the potential side channel connection at application. Sportsman Island was identified in the Yakima Basin Steelhead Recovery Plan, the Subbasin Plan, the Reaches Report, and the Upper Yakima Comprehensive Flood Hazard Management Plan as critical habitat for salmonids in the Yakima Basin.
At Hartford Road, the County removed 170’ of toe rock from a recently modified levee upstream of the Terrace Heights Bridge and excavated a 185’ long starter channel to direct high flows onto the property. The starter channel wasn't originally planned but its importance became evidnet during construction. Both worksites have existing flood control easements that were exercised to allow the project to move forward. This project is expected to benefit Chinook and Coho salmon, steelhead, and Bull Trout.