Scope of Work Change:  Due to changes in support in completing the Tumalum Culvert replacement in 2023, we are shifting funding priority in this contract to supporting the filling of a data gap related to warm water inputs from off channel impoundments operated by WDFW in the Tucannon River, as well as cold water refuge areas, in support of the Tucannon Lakes Assessment & Concept Designs (73982 REL164) being implemented by CTUIR.  Filling this data gap will help the Programmatic implementers prioritize and design more informed projects for spring Chinook.  The data will also be built into a web-based layer that could be used as a baseline for comparing uplift from implemented projects. The Tumalum culvert replacement project will be revisited in the future when partner agencies and funding are better aligned.

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 as runs declined to less than 200 adult fish. 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 CTUIR collaborates in the Programmatic Project, as a project implementer in support of programmatic goals, consistent with the CTUIR River Vision: a desired riverine system that is shaped and maintained by the dynamic interactions and interconnections of its natural physical and ecological processes. The restoration actions proposed for implementation in the prioritized river segments promote and enhance the interconnected nature of the five primary touchstones of the Tribes' Vision: a) hydrology, b) geomorphology, c) connectivity, d) riparian community, and e) aquatic biota.  

Major limiting factors influencing the condition of these touchstones throughout the project reaches proposed for treatment in the watershed, include:  
•    Past land use practices including logging, livestock grazing, irrigated agriculture and construction of the Tucannon Lakes, 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 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 County 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 explicit 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 (4) increased retention and storage of in-channel bed load sediments. With these prioritization goals, the Tucannon Implementer 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 Implementer 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.

[Tumalum Project Area Summary retained here for future reference: The Tumalum Project Area is located within the active river channel and floodplain of the Tucannon River, on private property. The project entails replacing a 65 feet long 10 feet wide CMP arch pipe with a 60 feet long 15 feet wide four-sided concrete box culvert following WDFW’s stream simulation design guidelines. A four-sided box culvert was selected over a three-sided culvert or bridge to avoid need for foundation work and to minimize construction time. In consideration of the prevailing slope in the project reach, the streambed design includes small steps composed of coarser substrates similar in size to upstream and downstream of the culvert location. Habitat boulders will be placed randomly within the culvert to increase roughness and prevent a hydraulic jump from forming during high flows. Logs with rootwads will be installed interlocked with existing trees downstream of the culvert to provide holding habitat and reduce velocities upstream in the culvert to support step stability. Columbia County roadway safety design requirements will be included as part of the project, including installing a guard rail which will block access to a gate on private land. A new constructed approach will be required to access the gate.]