DESCRIPTION
The project reach is west of Upper Beaver Creek Road on two land parcels recently purchased by the Methow Salmon Recovery Foundation using Yakama Nation Accord funds provided by the Bonneville Power Administration. The parcels are separated from each other by approximately 1000 feet of private land. The down valley parcel includes approximately 2200 linear feet of Beaver Creek and will be referred to as the Lower Project Area. The up valley parcel includes approximately 1500 linear feet of Beaver Creek and will be referred to as the Upper Project Area. Due to laterally stable channel conditions within much of the project reach, a key habitat enhancement strategy is to use imported large wood material to create hydraulic conditions that will scour new pools and deepen existing pools. In areas that are not deeply entrenched and have robust riparian areas, wood placements can be configured to span more of the active channel to create even more complex habitat by gradual channel migration or side channel development into healthy riparian areas. Immobile lag deposits in the Lower Project area limit enhancement opportunities so imported large wood structures are the main enhancements proposed for that reach. The Upper Project area affords a more varied palette of enhancement opportunities. Current plans include the construction of 12 engineered log structures (ELS), reactivation of a natural spring channel to create off channel juvenile fish rearing opportunities, one relic side ch
This area has been identified as an important migration corridor, juvenile rearing area, and spawning area for three ESA-listed anadromous salmonid stocks (Upper Columbia Steelhead, Bull Trout and Upper Columbia Spring Chinook). Historic and continuing land uses in this area have greatly altered the natural riverine processes, simplifying habitat and decreasing production throughout the system. Impaired habitat features include: floodplains, riparian areas, large wood recruitment, channel confinement, sedimentation, low flows (WA DOE 303d listing), invasive fish species and beaver removal (Andonaegui, 2000).
Installing instream structures will increase spawning, rearing and resting habitat for salmonids, provide places of refugia from high instream flow, and increase interstitial space for benthic organisms. Each piece of wood or engineered log structure that is installed will increase the structural complexity and diversity of instream habitat. In-stream wood creates cover, pools, reduces sediment and increases oxygen levels caused by turbulence as water flows over and through the structures. In areas where the width/depth ratio of the stream has been altered by removal of LWD, channelization, and land use change, the addition of in-stream wood restores historic function. Finally, instream structures can restore historic hydrologic regimes, decrease high flow velocities, and deflect flows into adjoining flood plain areas, restoring connections to juvenile refugia and rearing habitat in wetlands, old channels, and the floodplain at large.
This project will improve fish habitat by constructing large wood structures, improving and creating pools, promoting channel migration, reduce erosion, creating off channel rearing opportunities and enhance the shading, cover, and filtering properties of the riparian corridor.
The proposed project includes the following work elements:
- Construction of 12 engineered log structures (ELS) to promote pool depth, bank inundation during high flows, reduce erosion, and provide instream habitat complexity.
- Redistribute spring water into historic channel alignment to create off channel rearing habitat and hydraulic refuge for juvenile salmonids.
- Promote channel migration to encourage natural large wood recruitment and promote side channel formation in healthy riparian areas.
- Install a channel spanning log structure designed to redirect the flow of Beaver Creek into a relic side channel. This will increase habitat quantity and quality currently lost due to a channel avulsion.
- Replant impaired riparian areas with native grasses, shrubs and trees.
