Third Street Bridge on Garden Creek – City of Challis

An engineering firm was hired to review and provide a draft design concept to address the fish passage barrier that resulted from the new concrete culvert installed in 2019 in Garden Creek on Third Street to replace two undersize culverts that had been damaged in the 2017 high water event. The Alternative Analysis Report provided five alternatives to the City. The most viable alternative to address the passage issue was to install a new bridge to replace the culverts installed by FEMA funding.

Custer SWCD staff and River Structures met with the Mayor before starting the design review and after completion to review these alternatives. The City of Challis is unable at the current time to expend additional City budget to address this replacement. The other alternatives are a concern due to either maintenance or the lack of size of the culvert to meet high flows, even without the additional channel roughness or inserts. The Custer SWCD will continue to work with the City to address any options for funding a new bridge. River Structures provided a preliminary design for the bridge alternative that has been provide to the City of Challis.

This project had both 2014 and 2015 PCSRF funds, and is reported under the FY 14 award. Both FY14 and FY 15 awards expired on 6/30/20, and this project was completed within that timeline.

Create passage for all species of fish through the Third Street box culvert on Garden Creek. Phase I would be to develop design alternatives that could address fish passage. This project will address improved access to spawning/incubation and rearing habitat for Spring/Summer Chinook and Steelhead Trout.