This project targets the Lower Mainstem Clearwater River population of ESA listed Snake River A-run steelhead and the designated critical habitat, reintroduced Spring Chinook and Coho, and native fish within the Sweetwater Creek watershed. There are five bridges and two fords located along 1.2 miles of designated critical habitat and affecting 31.0 acres of riparian habitat. Project outcome is an assessment and designs on two fords and five bridges, which focuses on increased quality and quantity of instream habitat, improved stream process of flood conveyance, floodplain and side channel engagement, and sediment transport through new bridge designs, ford removal, stream crossing reduction, and improved floodplain access. Removing fords would be the highest priority, followed by upsizing of as many as 5 bridges to provide adequate passage, flow, and transport through the reach. This first phase will prioritize crossings to be removed, improved, or combined. Once this determination is established, any residual funding will be used to develop designs for crossings that will remain for improvements/combinations, or restoration designs on crossings to be removed. The second phase will consist of design/engineering and NEPA compliance. The final phase will be construction of improved crossings and/or stream restoration.
This project addresses 3 of the 6 limiting factors for the Lapwai Creek Watershed (habitat diversity, sedimentation, and passage) which were identified in the Lapwai Creek Ecological Restoration Strategy(LCERS), developed in conjunction between the Nez Perce Tribe, Nez Perce Soil and Water Conservation District, and other private & public stakeholders within the watershed. This project falls within Sweetwater Creek Reach 1. Sweetwater Creek Reach 1 was the second highest ranking assessment unit in 2009 when the LCERS was developed even though surface diversions reduced streamflow by almost 100%. Currently, the Tribe is involved in the Lewiston Orchards Project Water Exchange and Title Transfer Project (LOP) which is reducing the surface diversions to increase streamflow to the Sweetwater Creek watershed. Prior to 2006 summer base flows were reduced to 0.0 cfs. The 2020 Biological Assessment proposes base flows with up to 12.5 cfs. These increased stream flows along with the with this proposed project will restore, provide access to, and increase the amount designated critical habitat within Sweetwater Creek.
Project anticipates analysis of stream crossings in relation to types of access, types of crossing (fords, bridges, etc.) redundancy, land ownership, rights-of-way, easements, and condition. Upon completion of analysis, crossings selected for removal, improvement, or habitat restoration will be assigned a ranking based on landowner participation and funding, overall habitat improvement, and cost of project.
Outcomes of this project would be able to address a multitude of factors inadequate or excessive crossings affecting passage and designated critical habitat through the reach. Undersized crossings could be upsized to allow proper flow regimes and prevent upstream aggradation and downstream degradation of spawning and rearing habitat. Agricultural fords could be replaced with proper bridges or culverts, specifically addressing artificial substrate modification, increases in sediment, and elevation passage issues. Redundant crossings could be removed and adjacent riparian habitat restored.
Worksite #1 Lower Sweetwater Creek RM 2.3-3.5:
Propose to develop an assessment of complex of stream crossings consisting of fords and bridges, which are currently causing passage and stranding issues for ESA-species and repeated flooding, aggradation, and degradation. Propose to use remaining funds to produce designs for preferred assessment options.
