Background: The Tucannon River in Southeast Washington flows north out of the Blue Mountains into the Snake River, and is the ancestral boundary between the Confederated Tribes of the Umatilla Indian Reservation and the Nez Perce Tribe. The Tucannon watershed supports the only remaining population of spring Chinook (Oncorhynchus tshawytscha) in the lower Snake River. Early fish estimates show the Tucannon once produced thousands of salmon annually, but now only produces a few hundred adult spring Chinook each year. In 1992, spring Chinook were listed as threatened under the Endangered Species Act (ESA) as runs declined to less than 200 adult fish. The basin also supports summer steelhead and fall Chinook also protected under ESA.  Because of the Tucannon River’s importance to the Snake River Basin, BPA provides funding for a Programmatic Habitat Project in the Tucannon River.

The Tucannon Programmatic Project is managed by the Snake River Salmon Recovery Board (SRSRB) through a parent contract for operational support, organizational management, implementation assistance, and annual reporting. The goal of the Tucannon River programmatic is to restore natural channel processes in the spring Chinook priority restoration reaches of the Tucannon River, leading to improved population productivity and abundance. The Columbia Conservation District (CCD) collaborates in the Programmatic Project, as a project implementer in support of programmatic goals, consistent with the Salmon Recovery Plan for SE Washington and the Tucannon Conceptual Restoration Plan (Anchor QEA 2020).  The Restoration Plan’s focus is developing a riverine system that is shaped and maintained by natural physical and ecological processes. The restoration actions proposed for implementation in the prioritized river segments promote and enhance the interconnected nature of hydrology, geomorphology, connectivity, riparian community, and native fish and wildlife.  

Major limiting factors influencing naturally functioning conditions throughout the project reaches proposed for treatment in the watershed, include:  
•    Past land use and management practices including logging, grazing, agriculture, channel modification, stream bank armoring, the placement of infrastructure and construction of the Tucannon Lakes in the floodplain, in addition to recent large forest fires in the headwaters, have created conditions in the Tucannon River that have over-simplified the stream channel and drastically reduced the productivity, abundance and sustainability of the spring Chinook population.
•    Channel simplification caused by channel confinement (levees, lakes, roads) and straightening (pushing the channel to the valley wall) has led to a loss of floodplain connectivity (channel incision), increased stream velocities, and loss of pool habitat. These factors have combined to decrease quality habitat for adult and juvenile Spring and Fall Chinook salmon, steelhead, and Bull Trout, leaving these unique populations at risk.

Overview: After several years of opportunistic restoration in the Tucannon Basin, as a Model Watershed (1997-2008), the Columbia Conservation District (CCD) brought all parties to the table to work on a new restoration planning document. The Tucannon River Geomorphic Assessment & Habitat Restoration Study (Anchor QEA, April 2011) identified and prioritized stream reaches and restoration actions which would best improve habitat for salmonids. Refocusing on the high priority areas for spring Chinook, the CCD coordinated the development of a habitat restoration plan that prioritized work from RM-20 upstream to RM-50. After 10 years of implementing the first plan, it became obvious that program managers needed to move further down the watershed and start working in the lower Tucannon River. In 2018, through the Tucannon River Programmatic Habitat project, the CCD initiated an update of the Tucannon Restoration Plan to help refocus restoration efforts and include the rest of the Tucannon River from RM-20 downstream to the confluence of the Snake River.

The Updated Tucannon Conceptual Restoration Plan (Anchor QEA, In Process) will prioritize projects into three Tiers (1-3) based on these prioritization goals: (1) increased complexity at low-winter flows, (2) increased complexity during spring and winter peak flows, (3) re-connection of disconnected and abandoned floodplains, (4) improved quantity and quality of pools, and (5) increased retention and storage of in-channel bedload sediments. With these new prioritization goals, the Tucannon program implementers will select project areas in the Tucannon that focus on increasing habitat condition for adult and juvenile Snake River spring Chinook, steelhead and Bull Trout. The refocusing of prioritization goals will ensure Tucannon Implementers are selecting project areas for future restoration actions that are large enough to make a meaningful difference, be cost-effective relative to those benefits, and remain feasible to construct.

Project Area Summary: The Project Area (PA) 26 Phase III-IV proposal is a large woody debris and floodplain connectivity project, located on private property with the goal of increasing river channel roughness, floodplain connectivity and side channel connectivity within a 1.7 mile long reach of the Tucannon River, in Columbia County (RM 24.4 – 26.1). Geomorphic processes, floodplain connectivity, and accompanying habitat for spring Chinook and summer steelhead within the PA-26 reach have been influenced by historic land use practices, tree harvest/clearing, and excavation and other bulk earthwork activities at various locations within the 100-year floodplain. These activities have led to limited instream and floodplain habitat complexity, degraded floodplain connectivity, degraded riparian condition, elevated summer water temperatures, and low channel complexity are all key habitat limiting factors for Chinook and steelhead (Anchor QEA 2011a). This project aims to address many of these factors through stream restoration and habitat enhancement which would encourage natural functioning conditions.  

Project Area Background: The overall project area (2.9-mile reach) has been broken out into a number of implementation work-windows based on available funding, landowner participation, and adaptive management considerations. In Phase I (initiated in 2011), river levees and gravel berms were removed and breached throughout the entire reach as part of the 2.9-mile-long PA 26.  The goal of Phase I was to restore properly functioning geomorphic condition by reducing river channel and floodplain confinement.  In 2011, levee removal was a new and innovative restoration technique for SE Washington State, and it was determined that a conservative approach would be implemented where the levee would be removed and set back and channel modifications would be delayed to make observations on how the channel would recover naturally (letting the river do the work).  

Phase 1 continued through 2013, when twelve log jams were placed within the upper reach to provide fish cover. Monitoring surveys conducted by CHaMP and the Tucannon Habitat Programmatic between 2012 and 2017 indicated limited change in channel complexity or floodplain connectivity.  Gravel storage within the reach, although improved, remained highly mobile, and the ~124 ac of floodplain liberated by the 2011 levee removal project had experienced very limited flood inundation.  The CHaMP program recommended additional LWD structure placement to sort and retain gravel bars to encourage lateral channel migration and increased floodplain inundation frequency and duration.

Phase II was done in 2021 in contract 87504. Phase II focused on LWD loading on the upper ~0.8 mile of the Phase I (2.9 mi) project reach on which restoration actions were performed in 2011 & 2013. The LWD placements were designed to increase floodplain connectivity in areas where previous levee removals and modifications were implemented in 2011.

Phase III/IV will be implemented primarily in 2023, with any remaining project components completed in 2024. Phase III/IV is a 1.7 mile reach of privately land owned by a single individual with an opportunity to improve floodplain connectivity to ~57 acres through a combination of side channel pilot cuts and LWD placement, levee setback, gravel berm leveling and channel construction.  Pilot cuts are being placed in combination with 56 LWD structures to reconnect 1.5 miles of perennial side channel habitat currently disconnected.  Side channel and flow paths exist within the 60 acres of available floodplain.  Reconnecting available floodplain will require maintaining the landowner's farm road access across the river (railcar bridge for main channel as well as hardened fords for side channel flow paths) to cattle pasture near the upper end of the project area.

Phase III/IV Objectives:
•    Place 72 LWD structures in channel over ~6,400’ of river channel.
•    Place 16 LWD structures on the floodplain
•    Cut ~450’ of side channel pilots to connect 7,900’ of side channels and >60ac of low floodplain
•    Levee modification (remove set back 1,600’) to reconnect 3.7 ac of floodplain
•    Remove 800’ of gravel berms to reconnect/create side 2,600’ additional side channels and 3.4 additional floodplain acers.  
•    Modification to existing irrigation system to accommodate floodplain reconnection.

Final designs for Phase III/IV are attached to this contract in CBFish.