The Pahsimeroi River, a tributary to the mainstem Salmon River, contains Snake River Spring/Summer Chinook, Steelhead, cutthroat trout, westslope trout, bull trout, and interior red-band trout.  Work in this contract will address habitat restoration for these species, particularly Chinook and steelhead.

The NOAA Fisheries Spring/Summer Chinook and Steelhead Recovery Plan (2017) identifies limiting factors in the Pahsimeroi River for Spring/Summer Chinook as low stream flows, passage barriers/connectivity, degraded riparian conditions, degraded channel form and lack of complexity, and water quality. Limiting factors for Pahsimeroi River Steelhead populations include reduced flows during critical periods, migration barriers, elevated water temperatures, degraded riparian conditions, and entrainment.  

Habitat restoration and recovery needs for these species include increased stream flows in the main-stem Pahsimeroi and its tributaries. The Custer SWCD is addressing the need to improve flows by working with the Idaho Department of Water Resources and with individual water users to develop water conservation measures, modify existing barriers caused by diversion or culverts, improve riparian conditions by restoring riparian vegetation, and reducing entrainment by screening irrigation ditches to NOAA standards.

The projects identified in this statement of work address these recovery needs by installing a pipeline and an irrigation diversion structure on the project area known as P-17. The pipeline is designed to make the existing irrigation system more efficient and to leave an additional 3.2-6 cfs in the Pahsimeroi River. A new irrigation diversion will also be installed on P-17 to address a partial passage barrier. NRCS will provide design and assist in implementation for the irrigation infrastructure. IDFG will design and install the fish screen under a separate contract. (Screen installations are done via a separate BPA project for IDFG’s Screen Shop (2007-399-00)).

Work in this contract will also include installing riparian fencing and a stock-water system to provide water away from the riparian area and eliminate streamside impacts by livestock. This reach is on IDL (state land) property, which is also part of a channel restoration project funded and implemented by IDFG’s Pahsimeroi contract (2008-603-00 contract 76913 Release 006). Fencing will exclude livestock from the restored channel and riparian area to protect the project area and allow vegetative cover to establish.

These projects have been developed and ranked for implementation by the Custer SWCD in conjunction with the Pahsimeroi Basin Subcommittee group, which includes the Idaho Department of Fish and Game, U. S. Bureau of Reclamation, Idaho Department of Water Resources, Natural Resources Conservation Service, Trout Unlimited, Idaho Office of Species Conservation, the Corps of Engineers, Custer and Lemhi counties, NOAA Fisheries, US Fish and Wildlife Service, and private landowners. This group meets monthly to plan and develop approaches to address restoration needs in the Pahsimeroi and its tributaries.

Out-year planning work in this contract includes multiple opportunities for riparian fencing in the Pahsimeroi and Patterson/Big Springs Creek as the Custer SWCD continue to work with landowners to develop these plans. Custer SWCD will continue to work with the Pahsimeroi Subcommittee to identify and prioritize these projects. This effort will be accomplished with Custer SWCD staff time under this contract. Any funding to complete repairs would be developed with BPA support in a subsequent contract.