This project is a component of the Bureau of Reclamation’s Yakima River Basin Integrated Water Resource Management Plan which focuses on water conservation, irrigation needs, fisheries, and watershed health. The project is intended to aid a sockeye salmon reintroduction program by the Yakama Nation tribe. Built in the 1930s, the earthfill dam eradicated sockeye salmon in the upper Yakima River Basin. While Lake Cle Elum existed prior to the dam, the 165-foot dam raised the level of the lake and blocked passage for
The facility consists of a multi-level inlet ramp with gated openings that will operate at various reservoir levels. It will feed into a structure designed to maximize fish survival as they travel to the downstream side of the dam. The tunnel will help juvenile sockeye migrating downstream to pass the Cle Elum Dam naturally.
JWF’s scope included constructing a tunnel from a portal downstream of the dam near the spillway to a secant pile shaft adjacent to the dam. Utilizing a 114-inch OD open-faced shield tunnel machine to excavate the 1,233 foot tunnel, initial ground support will be steel liner plate which will be grouted in place. Final tunnel liner is cast in place concrete to a 7-foot inner diameter finish.
Ground conditions for the entirety of the tunnel were excavated in glacial outwash which consists of densely packed fines, sands, gravels, and boulders of up to 36-inch diameter.