Beyeler Ranch, Upper Lemhi Enhancement Project (Phase 1 and Phase II)

Project Narrative

The Beyeler Ranch Upper Lemhi Habitat Enhancement Project improved habitat for juvenile spring Chinook salmon and summer steelhead in the mainstem upper Lemhi River and three spring channel tributaries to the Lemhi River. Trout Unlimited, the Upper Salmon Basin Watershed Program, U.S. Bureau of Reclamation, Bonneville Power Administration and Pacific Coast Salmon Recovery Funds worked together to improved habitat along 0.6 miles of the Lemhi River and 0.5 miles of spring channels. The project improved instream habitat complexity by constructing narrower channels, installing instream wood and willows weaves (found under other engineered structures in metrics), and building floodplain benches and islands. Willow plantings and plant protection from wildlife and cattle exclosure fencing have set this reach up for long term riparian growth and natural stream function. Project actions included creation/connection to off-channel habitat, creation of floodplain habitat, excavated pools, installation of instream wood structures, streambank stabilization, riparian planting and fencing. This project was originally scheduled to have four phases, with funding for phases 1 & 2 in this contract. The landowner decided to postpone phases 3 and 4, and scale back on phases 1 &2. Due to the reduction of the project scale, the total length of stream treated was reduced from 1.43 mi proposed to 1.1 mi actual. Meanders were not re-activated, nor was channel bed restored. Off-stream channel created was reduced from the 0.23 mile proposed to 0.1 mi, the number of instream structures installed was decreased from 154 to 143, and consequently pools expected to be created through channel structure placement was reduced from 35 to 20. Riparian metrics were likewise reduced from 2.4 miles/2.8 acres proposed to 1.3 mi/1.5 ac planted. An amendment to decrease PCSRF funds and extend was completed in December 2021. Additional channel length with slower water, access to floodplain, woody instream habitat, and overhanging riparian habitat are some of the key benefits to juvenile salmonids that will be realized by the project. Increased channel length will provide additional habitat area, decrease channel slope, and decrease instream velocity. Channel narrowing will increase channel depth for increased vertical (bank) habitat, decreased solar input, and increased fish cover. Woody habitat will create complex assemblages to provide feeding areas, cover, and velocity refuge during the summer and concealment habitat during the winter for juvenile salmonids. Woody instream habitat will also provide substrate scour and sorting which will benefit adults during migration, staging, and spawning. Willow planting and protection will be conducted in areas where channel migration is occurring at an unnaturally high rate due to historic willow removal actions. In these areas, excessive channel migration, facilitated by willow removal, has been the mechanism for formation of overly wide channels that cut off meanders, thus becoming wider, shallower, and steeper, with higher water velocities and reduced habitat complexity. Willow planting and protection in these areas will ultimately reverse these trends.