The primary goal of the Fort Hall Habitat Restoration project is to restore, enhance, and protect Fort Hall Indian Reservation (Reservation) streams so they can support native fish populations at near historic levels. The Fort Hall Bottoms area provides a range of ecosystem services important to the Shoshone-Bannock Tribes, including sustaining populations of Yellowstone cutthroat trout (Oncorhynchus clarkii bouvieri) and other native fish. The range and distribution of Yellowstone cutthroat trout have been impacted in many tributaries of the Snake River by competition with other salmonids and by habitat degradation. Streams on the Reservation have been negatively affected (i.e. loss of riparian vegetation, down cutting, and lateral scouring of stream banks) by a variety of sources, including livestock grazing, American Falls Reservoir (AFR) construction and operations, and the 1976 Teton Dam collapse.  Damage to stream banks from years of unrestricted grazing continues to be a problem on Reservation streams. Rapid flooding and drafting of American Falls Reservoir in conjunction with seasonal freeze-thaw cycles is a major cause of stream bank failures on lowland Reservation streams. Negative impacts from stream bank failures include, but are not limited to: widened channels, a reduction in riparian vegetation and in-stream cover; increased summer water temperatures, and deposition of fines on critical spawning and rearing substrates.  

The Doug’s Sloping Enhancement Project was located in the upstream reach of Spring Creek (near the spring head), the largest spring-fed stream on the SBT's reservation in the Fort Hall Bottoms. The project was constructed in 2020 and 2021 and was approximately one mile in length. The goal of the project was to improve habitat for Yellowstone Cutthroat Trout by increasing channel complexity through narrowing the channel, increasing depth and velocity, constructing riffles, creating a floodplain, revegetating with native plants, constructing a new meander, creating a side channel with a pond, and adding woody structures.

The original revegetation efforts were of limited success.  Invasive weeds have established themselves in the equipment staging area and need to be treated.  Livestock and wildlife have consumed and damaged much of the original willow plantings and seeding, prior to an exclosure fence being completed in 2022.  These areas will be replanted with willow cuttings and a native seed mix. Invasive plants, primarily Russian Olive, Canada Thistle, Scotch Thistle, White Top, Russian Knapweed, and Spotted Knapweed, will be treated with a combination of mechanical and chemical means.

The Oxbow Pond, constructed as a side channel in the original project, is shallower than intended (only a couple feet deep), choked with macrophytes, and warms the water.  This pond will be dredged to improve rearing habitat (deeper and colder) and the inlet and outlet will be modified to increase flow through the pond/side channel.  The gravel removed from the pond will be used as a source to enhance/stabilize the riffles.

Five riffles were constructed in the original project to help stabilize the channel, reduce downcutting, and raise the water table to reconnect the floodplain.  The riffles also provide spawning habitat for Yellowstone Cutthroat Trout.  However, the gravel used was too small to maintain the riffles.  As a result, the channel has down-cut approximately 0.5-0.75 feet at the upstream end of the riffles.  Larger gravel, obtained from dredging the oxbow pond and from an outside source, will be used to stabilize and restore the function of these riffles.

The Spring Creek Weir assessment process will provide two alternatives to be decided: (1) the full removal of the weir or (2) the ecologically appropriate abandonment of the weir in place.  It is believed it was originally installed as either a grade control structure or as a fish-management weir.

Approximately 74 acres of upland and riparian habitat in three previously completed restoration sites (Doug's slope, Cable Bridge, and Diggie Creek) will be treated for noxious weeds and revegetated with native plant species.   Thirty-four acres (22 riparian and 12 upland acres) of the Doug's Sloping project area (including the 7-acre staging area), 30 acres of the Cable Bridge Project area (six riparian and 24 upland acres), and 10 acres of the Diggie Creek project area (six riparian and four upland acres) will be treated.

In FY25 20,000 live plants that included Nebraska sedge, beaked sedge, Eleocharis spp., and several forbs were planted for erosion stabilization and in FY26 similar efforts will take place as part of a coordinated vegetation management program with Living Earth LLC.

Through collaboration with Idaho State University (ISU), data collection and monitoring will continue to assess habitat conditions and fish use as restoration work is completed.  Monitoring will include Yellowstone cutthroat trout densities in project areas as well as post-implementation data collection of habitat condition such as silt and water depth readings to compare pre- and post-construction site conditions.  ISU provides its own funding for this effort and the SBT provides additional manpower.

Fort Hall Bottoms focus remains on sustaining populations of Yellowstone cutthroat trout. The sampling results will contribute to development of future management strategies and restoration actions.