Upper Wenatchee Floodplain Reconnection (RM37-38)

Project is intended to enhance in-stream habitat conditions and better connect an ~55-acre river-left floodplain (and associated channel network) between river miles 36.5 and 37.9 of the upper Wenatchee River. In-stream project-constructed elements will occur between river miles 37.0 and 37.9, and include installation of six engineered log jams, 12 boulder clusters (4-5 large boulders/cluster), and 18 side-channel habitat logs. ELJs are designed to direct flows towards the river-left floodplain and improve mainstem habitats. The boulder clusters and habitat logs are to enhance cover and hydraulic diversity in mainstem and side channel areas. The project also includes excavation of a river left pilot channel to better connect the mainstem channel to the existing floodplain channel network. Under the current design iteration (60% Preliminary Designs), the pilot channel is expected to be ~225 ft long x ~40 ft wide (with a wider, flared inlet).To access work areas, the project will re-open and improve ~1,300 lf of USFS road NF-7906 that was previously closed and partially obliterated by USFS. This road segment will be closed, re-contoured and re-vegetated post-construction. To isolate in-water work areas around ELJs and pilot channel inlet and to get heavy equipment and materials  across the Wenatchee River, the project will construct temporary coffer dams and a multi-span, temporary bridge. These features will be removed once in-stream and floodplain work are complete.

The overall goal of the proposed project is to implement restoration actions that address Limiting Factors identified for Reach 2 of the Wenatchee River-Beaver Creek AU including cover-wood, pool quantity and quality, deep pools, and floodplain connectivity/off-channel side channels. The project will construct restoration treatments developed through an iterative and well-reviewed design process.
Specific project goals are: (1) Increase flow connectivity and juvenile fish access to floodplain habitats; (2) Promote lateral channel migration, sediment deposition and sorting, and organic matter retention; and (3) Enhance habitat diversity and quality via increased pools and cover and better floodplain and side channel connectivity.
Desired future conditions include a well-connected, river-left floodplain and a complex mainstem channel with more pools and persistent large wood accumulations, and an enhanced capacity for organic matter retention and sediment deposition/sorting to facilitate channel evolution and creation of additional cover, gravel bars and islands, more suitable spawning gravels and other habitat features. Benefits from the proposed actions are expected to be realized very quickly, persist for decades and facilitate subsequent stream evolution. They are expected to improve conditions year-round for a number of steelhead and spring Chinook life stages including summer and winter rearing, spawning, incubation, and holding/maturation.