Tribal Allotment 369B Habitat Restoration Phase II (#1)

The Nez Perce Tribe DFRM will implement a bridge replacement on a 0.10 mile segment of Sweetwater Creek near the confluence of Sweetwater Creek and Lapwai Creek. Current habitat conditions include a straightened stream segment which contains little LWD, confined by Webb Road and agricultural fields, no side channels or other lateral habitat, a floodplain that has been converted to agricultural or cut off by the county road, and limited riparian vegetation. The stream is confined by a concrete wall forcing it into an undersized and aging bridge. The current bridge has a 100-year backwater level of two feet and an overtopping flood at the 2-year interval. This leads to frequent juvenile salmonid stranding in the adjacent agricultural fields.



Project actions include: Replacing existing bridge with a new bridge that will, pass flows of a 100-year event, meet county bridge requirements, allow full aquatic organism passage at all flows



Phase I of this project, which has already been funded and will be implemented in 2027, consists of stream realignment and habitat restoration, while phase II of this project will consist of an undersized bridge replacement and associated road work (performed under this PCSRF project 23-NezP-06) and associated habitat work (to be performed under project 24-NezP-06).





CRITFC PCSRF funding will be used in conjunction with Idaho OSC PCSRF, BPA, Nez Perce Tribal SRBA, and Nez Perce County funding sources to complete phase II which includes the undersized bridge replacement.





Worksite #1 Tribal Allotment 369B – Phase 2 (#1)



Proposed Work:



Phase II of this habitat restoration and fish stranding project will consist or replacing the drastically undersized bridge with an appropriate AOP structure that will pass all life stages of ESA-listed Snake River ESU steelhead, reintroduced Spring Chinook and Coho Salmon, and all other resident fish and aquatic organisms.

This project focuses on ESU Snake River Basin steelhead trout DPS. The project site lies within designated critical habitat for ESA-listed Snake River Basin steelhead trout, and Essential Fish Habitat for multiple salmonid species including ESA-listed Snake River Basin steelhead, ESA-listed Snake River Fall-run Chinook salmon, and reintroduced Spring Chinook and Coho salmon.



This second phase of the project will address the undersized bridge that is creating upstream channel aggradation, downstream channel degradation, and increased occurrences of fish stranding in adjacent agricultural fields. A properly sized bridge will allow appropriate sediment transport, large woody debris transport, and eliminate stranding caused by the existing undersized bridge. This will also allow the upstream habitat work done in phase I to remain stable as the new bridge will not contribute to upstream sediment deposition.