Lemhi River at Kenny Creek Habitat Project

Project Narrative

The Lemhi Soil and Water Conservation District (LSWCD) will construct habitat treatments on a 0.30 mile segment of the Lemhi River located near the confluence of Kenney Creek. Current habitat conditions include a straightened channelized river segment confined by agricultural land, containing no side channel or floodplain connectivity through a high-quality riparian forest. Project actions will focus on constructing a pilot side channel and adjacent regraded floodplain that will take advantage of an existing spring and series of swales to form a more complex side channel network. The project will also install a series of woody structures, individual logs, and excavate pools within the excavated side channel. The project goal is to increase habitat complexity and capacity for juvenile salmon and steelhead. The site is located at the downstream end of the primary Chinook salmon production areas in the Lemhi Basin and will directly benefit juvenile life stages. Project actions to meet these objectives include: 1) side channel and floodplain creation, 2) flood-plain reactivation, 3) installation of habitat features (i.e. woody debris), 4) excavation of pools within the side channel network, and 5) riparian planting and seeding. Constructing the side channel to encourage a portion of the Lemhi River into the existing natural floodplain directly increases habitat capacity for juvenile life stages of salmon and steelhead. Improving the current condition through lateral habitat connectivity, developing habitat complexity in the form of woody debris structures, and riparian zone restoration will result in improved survival for all freshwater juvenile life stages. Furthermore, the magnitude of these affects will be substantial since the project is located downstream of the Lemhi primary Chinook salmon production area. Immediately upstream of the project site, the Lemhi River is a heavily incised single thread channel with no functional summer rearing or wintering habitat. As such, the project is ideally located to provide much needed habitat for rearing parr that are displaced by spring high flows from upstream production areas, and for pre-smolts moving out of the production areas in the fall in preparation for overwintering. The proposed project directly addresses these life stages by improving floodplain diversity.