Lemhi River Mile 32 Restoration and Diversion Consolidation

The Lemhi SWCD had proposed to implement an irrigation infrastructure project to close a diversion on the Lemhi River and pipe water around an area designated for habitat restoration on 0.95 mile of the Lemhi River and 0.06 mile of Hayden Creek. Numerous habitat actions were to take place at the site, where conditions include a straightened channelized homogeneous river segment that contained no instream woody material, disengaged floodplain, and limited riparian vegetation. Lemhi SWCD was the lead on the diversion portion of the project and intended to subcontract the habitat restoration actions to Trout Unlimited (TU).



During project development, the proposed irrigation consolidation was protested by neighboring ranches and Lemhi SWCD was not able to find a way forward that suited all parties. The landowner farthest downstream, on whose property the consolidation was to take place, dropped out of the project. The other two landowners where the majority of habitat actions were to take place were still on board to complete the project. However, as there was no longer the project portion to be completed by Lemhi SWCD, it made more sense for TU to become the project sponsor and hold their own contract with OSC. Habitat restoration actions may be found under PCSRF Project 014 21 SA, Lemhi RM32 Habitat Enhancement Project, Confluence Phase.

Developing a large portion of this property into more of a natural floodplain while restoring natural river processes and function will directly increase habitat capacity for juvenile life stages of salmon and steelhead. Improving the current condition by increasing river sinuosity, developing habitat complexity in the form of woody debris structures, constructing side channels, and riparian zone restoration will result in improved survival for all freshwater juvenile life stages. The magnitude of these affects will be substantial since the project is located at the confluence of the Lemhi River and Hayden Creek primary Chinook salmon production areas. The cold clear Hayden Creek waters mix with the nutrient rich Lemhi River waters and create a prime location for summer parr and overwintering juvenile steelhead and salmon.