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, 2021) prioritizes 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 selected 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) 34 design 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 1.23-mile-long reach of the Tucannon River, in Columbia County (RM 11.5.4 – 12.75). Geomorphic processes, floodplain connectivity, and accompanying habitat for spring Chinook and summer steelhead within the PA-34 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.  

PA34.1 & 34.2 will be implemented primarily in 2024, with any remaining project components completed in 2025. The project is a 1.23-mile reach of land privately owned by three individuals with an opportunity to improve floodplain connectivity through a combination of LWD placement, side channel connection and rip-rap removal.  The rip-rap removal will be performed to reduce velocities at the existing property access bridge, reducing downstream stream power.  To increase channel complexity and to bifurcate stream flows, 57 LWD structures are being placed in channel with an additional 10 structures being built on the floodplain to add roughness during larger flows.  Through the implementation of this project, it is anticipated a near doubling of perennial side channel length will occur, increasing connection to >21 acres of floodplain, including connection to 3.5 disconnected acres.

Objectives:
•    Place 57 LWD structures in channel over ~6,400’ of river channel.
•    Place 10 LWD structures on the floodplain
•    Augment 0.75 mi of side channel by increase flow and LWD complexity, connect 1 mi’ of side channels (50% perennial) and >17.5 ac of low floodplain
•    Reconnect 3.5 ac of floodplain

Final designs for PA34.1 & 34.2 are being completed under (#94475) and will be attached to this contract in CBFish.