North Fork Walla Walla River RM 4.3-5.2 Floodplain Restoration Design

The North Fork Walla Walla River is identified in numerous natural resource management guidance manuals as a priority location for restoration and protection. Designs focused on converting the channel back to the appropriate form and function with subsequent improvements to salmonid habitat suitability. The second design phase was completed from river mile 4.4-5.2. Landowner agreements were secured for a 10-year period and the majority of the valley width was made available for holistic floodplain restoration. Initial conceptual design alternatives were developed and circulated to review teams to solicit professional direction and attain decisions in regard to choice of preferred alternative chosen. As part of the alternative assessment, a matrix was developed to encompass the attributes and drawbacks to each alternative. Preliminary designs concepts were presented early in the development process to review teams and landowners to assure timely utilization of resources towards developing a viable design that could be approved, permitted and implemented in a timely manner. Upon receiving decisions regarding the chosen alternative, designs were advanced through engineer review stages at the 15%, 30%, 80% and 100% levels. Upon acceptance of the 80% design package by review entities, permitting was initiated. Input from the BPA review team at the 80% design level was used to shape development of the 100% final design level. Final, stamped designs were successfully produced during the Spring of 2024 with the intention of being implemented during the instream work window of 2024.

Recent counts of adult steelhead at McNary Dam migrating from the ocean to natal headwater streams are significantly (33-50%) below all-time lows. Mid-Columbia Steelhead and bull trout inhabit the NFWWR project area and are listed as threatened ESA species, with local populations declining in size and status trending towards high risk of extinction. The NFWWR is one of the last remaining primary steelhead spawning destination strongholds in the Walla Walla Basin. Therefore, steelhead suitability and inhabitance is potentially a key component toward recovery through protection, restoration, and enhancement of managerial actions in the NFWWR. WWBWC fish habitat restoration efforts target species of focus is steelhead, with indirect overlapping benefits to bull trout, spring chinook salmon, mountain whitefish, freshwater mussels, western brook lamprey, red band/rainbow trout. The magnitude of the NFWWR design project is 5-miles in length, and the implementation duration is potentially through 2028. The benefit of having controlled access, coupled with our ridgetop to ridgetop watershed approach, offers an opportunity to impact the recovery of the species significantly. We intend to potentially expand further onto public land as we have established strong partnerships with federal landowners located upstream from RM 9 after 2028 and concentrate on enhancing habitat complexity specifically for these species of concern. Granted, the NFWWR reaches upstream from RM 9 would not need the degree of restoration as required in the 5-mile treatment reach downstream as conditions on federal lands were such to display more resilience to flood impacts and therefore are categorized as being in a superior state. Our design of habitat restoration plans intends to address all life stages of salmonids to prevent bottlenecks from suppressing population growth with the ultimate goal of supporting the removal of Mid-Columbia Steelhead from the Threatened and Endangered Species List by reaching levels of viability.