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, which includes  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 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 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.  Stream restoration will continue to be the focus of the Fort Hall restoration work on the Bottoms.

Habitat restoration will remain the primary focus for the Fort Hall project in this contract.  Restoration work in this contract will address the Cable Bridge reach of Spring Creek. Construction for the Cable Bridge Spring Creek reach began in late summer-fall 2023 and will continue in this contract. Final designs are uploaded to this contract in CBFish.

The Cable Bridge project is located along Spring Creek, which is a spring-fed tributary to the American Falls Reservoir (AFR).  This project involves the enhancement of approximately 2,500 linear feet of Spring Creek near its confluence with Big Jimmy Creek. The project reach is situated near the upstream limit of the AFR’s backwater influence, which causes flow patterns to vary depending on the reservoir elevations.  This transitional character of the project reach results in habitat degradation largely caused by excessive deposition of suspended sediments; channel widening; bank erosion; bank sloughing; and the reintroduction of fine sediment to the stream system. These conditions are aggravated by the unstable conditions of the site’s streambanks in combination with the rapidly varying pool elevation of the AFR.

This project is intended to improve and stabilize these conditions through the following actions:

• Creating multiple-tiered, vegetated benches along the banks of the existing channel where steep, unvegetated, sloughing banks currently exist.
• Narrowing the stream channel in the free-flowing upstream length of the project reach by constructing vegetated, gravel banks along one or both sides of the stream.
• Narrowing the width of the effective flow in the project reach by dredging the preferred channel alignment and installing a series of natural tree/wood structures to slow stream velocities and to encourage the passive, natural development of emergent wetland benches.
• Restoring upstream fish passage into a small, spring-fed tributary by replacing a perched culvert and improving the stream channel downstream of the existing culvert.
• Implementing a revegetation plan as part of the proposed construction effort with a 3-year-long vegetation stewardship plan after construction.

The proposed project is anticipated to result in the following benefits and ecological uplift:

• Removing from the stream system roughly 17,000-cubic-yards of fine sediment;
• Converting roughly 2.4-acres of sediment-laden streambed to a gravel streambed;
• Converting roughly 1.5-acres of open water to emergent and scrub/shrub wetland; and
• Increasing the amount of native upland habitat by approximately 2.4-acres, while reseeding and enhancing a total of approximately 8.3-acres of upland habitat/vegetation.

Annual monitoring of Yellowstone cutthroat trout densities in project areas will continue as in previous contracts. Monitoring will also include post-implementation data collection of some silt and water depth readings to compare pre- and post-construction site conditions.  

This contract also includes work on community outreach and out-year planning.