Wimpey Creek (Skinner) Restoration

Project Narrative

The Wimpey Creek (Skinner) Restoration Project improved stream function and aquatic resources in the lower reach of Wimpey Creek. The project area is now a more natural landscape that maximizes ecological site potential through restoration of native plant communities, provision of preferred habitat for listed fish species, and establishment of a sustainable stream and floodplain morphology. Channel restoration resulted in 4,830 linear feet (6.1 acres) of improved aquatic habitat. Fish passage improvements opened 1.48 miles in Wimpey Creek for all life stages of ESA-listed and resident fish species. Two irrigation diversions acting as partial barriers were improved via one constructed riffle and one boulder-cascade weir. Channel shaping and realignment was completed within a 1.4 mile reach, and included 0.07 mile (0.1 acre) of off-channel stream construction and excavation of 17 pools. Channel rehabilitation actions were accomplished through reconnection of 1.8 acres of floodplain. Placement of 72 instream structures such as large wood, woody debris matrices, habitat structures, step pools, and riffles are providing bank stabilization, creating roughness, and increased habitat diversity. Seven pools will be created by scour. Riparian treatment consisted of native plant seeding, and installation of sod mats, potted plants, and willow stakes on approximately 6.1 acres within the 1.4 mile reach of Wimpey Creek. The buffer for most riparian planting was within 23 feet of Wimpey Creek. A cattle and wildlife exclusion fence was installed to protect 0.26 linear mile of Wimpey Creek on both sides. Additionally, five troughs and pipeline were installed to provide a source of water to livestock as they will no longer be able to access the creek. The project was completed on schedule; the original scheduled end date was incorrectly entered into the database. The existing limiting factors identified for Lemhi River steelhead and salmon are water quantity, water temperature, increased sediment, instream habitat complexity, riparian condition, floodplain connectivity, and passage barriers. The project actions to be implemented through this project will address these factors.