Background:  The Tucannon River basin is located in Southeast Washington State in Columbia and Garfield counties.  The system-wide restoration objective for the Tucannon River is to improve habitat conditions for Endangered Species Act (ESA) listed species (Snake River Spring Chinook and Steelhead) for all life history stages.  It is expected that improved habitat conditions will lead to an increase in the abundance of listed species returning to the river.  Increasing abundance will lead to de-listing of the species, which is the overall recovery goal for the system.  Previous efforts (CCD 2004; SRSRB 2006) have identified the habitat-limiting factors associated with the decline of ESA-listed populations.

Under prior contracts, the Columbia Conservation District (CCD) completed the Tucannon River Geomorphic Assessment & Habitat Restoration Study (Anchor QEA, April 2011), to identify and prioritize stream reaches and restoration actions which would best improve habitat for salmonids.  Focusing on the high priority areas for Tucannon spring Chinook, the Columbia Conservation District (CCD) coordinated the development of a habitat restoration plan for the Tucannon River from RM-20 upstream to RM-50; the District continued to work with the Snake River Salmon Recovery Board (SRSRB), through the Tucannon River Programmatic Habitat project, and extended the restoration plan from RM-20 downstream to the confluence of the Snake River. This Conceptual Restoration Plan (Anchor QEA, Nov 2011) has prioritized projects into three Tiers (1-3) based on the projected effects of implementation as a benefit to Snake River spring Chinook, cost-efficiency relative to those benefits, and the feasibility of construction.
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Overview:  Project Area 28 (PA-28) is a large scale/scope salmon habitat restoration project identified in previous assessment plans completed by Anchor QEA (2011).  The project reach is >2 miles in length, located within the active river channel and floodplain of the Tucannon River, on private land from ~RM-21.5 to approximately RM-19.35.  Restoration recommendations include the placement of Large Wood in the plane-bed sections of the side-channel, modification of existing floodplain restrictions, and installation  of an offset levee to improve floodplain connectivity and function. These identified restoration actions in the project area address limiting factor 6.2, channel structure and form; they are directly associated with the analysis of critical Limiting Factors (Floodplain Confinement) identified in the Expert Panel process; and they are targeted for implementation as a credit toward BPA's BiOp commitments.

The overall project goal is to increase/maintain proper floodplain structure and connectivity by increasing channel complexity and reconnecting historic channels. Objectives for the project are to: a) place LWD for habitat complexity and to improve stream channel form and function; b) increase proper floodplain structure/connectivity through additional wood placements; c) remove cobbled berms/spoil piles to reconnect existing historic flow paths; and d) construct an offset floodplain dike/levee to reactivate historic floodplain capacity and connect otherwise isolated habitats, while providing protection for agricultural production fields and associated landowner infrastructure.  The Columbia Conservation District (CCD) working with Kris Buelow, Snake River Salmon Recovery Board (SRSRB), the BPA Tucannon Programmatic Habitat project manager, will be implementing PA-28 in phases due to annual fiscal-year funding limitations and the constraints of instream work window periods.  

In FY16, the CCD plans to implement Phase I (A & B), including: (A)  (0.42 miles) of wood placement to improve channel and floodplain connectivity/ function; and (B) a (3,500') levee setback to provide landowner security while the newly emergent river channel conditions mature, and as floodplain connectivity adjusts, augmented by LWD placements and the modification and breaching of the existing cobbled-berm. Construction oversight encompasses both the Phase 1-A work in this contract, and the Phase 1-B component identified in the separate CCD contract for FY16 (#71864).

Purpose: Address high priority restoration actions including: improved channel complexity (LWD), floodplain connectivity, increased perennial channel length, and improved channel morphology. Immediate biological benefits will include decreased instream velocities during high-flows, and better connectivity with the floodplain.  Over time, channel processes will establish and maintain a variety of habitat elements and improved hydraulic conditions. The availability of ample and diverse habitats will increase the carrying capacity for juvenile salmonids and support habitat needs throughout the salmon lifecycle.
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Current Emphasis:  FY16 Programmatic (BPA) funding will be utilized for PA-28 Phase 1-A to place 0.42 miles of LWD in the main channel and side channel adjacent to the planned (Phase 1-B) 3,500' offset dike/levee designed under CCD contract #68607 and funded under pending CR-294902.  The purpose of the setback levee is also to provide landowner comfort and some measure of protection for adjacent agricultural production fields and associated infrastructure, as floodplain connectivity improves.  This project component is critical to ensuring landowner confidence in augmenting floodplain connectivity driven by LWD placements and cobble berm modification.  PA-28 Phase 1-B will be constructed in conjunction with Phase 1-A utilizing funds thru the CCD project (1994-018-06).  

Status:  This 14-month contract is to complete the implementation of the engineered design during the construction of Phase I (A & B); including:  
  -- any subsequent design modifications that may be required (following review), or as an adaptation in response to changes in channel geomorphology or site conditions (since completion of the design), and as adjusted during the initial construction phase
  -- modifications to or renewal of existing permits; or additional required permitting
  -- revised or amended environmental and cultural resource clearances
  -- adjustments to implementation strategies or approaches, including scheduling and logistics, that facilitate the construction of improved habitat features, in-channel structures, and other actions to restore ecological function
  -- vegetative plantings that are an integral component of the restoration design, to improve habitat function and connectivity; and
--  the remediation of construction impacts that includes the clean-up and restoration of construction access points and materials or equipment storage and mobilization areas.

In Phase1-A, the CCD will place 22 log jams in 0.42 miles of the main stem Tucannon and side channel adjacent to planned setback levee.  Structures placed in the main channel will be placed to enhance flow into side channel and maintain the channel over time.  Wood placed in the side channel is primarily for channel shaping (W/D, bed aggradation, and pool forming) and complexity cover.

Future Considerations: Project spans a minimum of two contract periods (24 - 36 month duration) covering Phase I (Year-1); and the subsequent implementation of the complete restoration design. It is anticipated future phases of this project area will follow in 2017-18, depending on available funding, including the construction of engineered structures and other features (Phase II- IV).  Additional, upcoming phases will:  
  --  place an additional 52 LWD structures and 50 single logs in the main channel and side channels;  
  --  re-water disconnected historic channels increasing perennial stream length up to a mile within the reach.
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Geomorphic Implications:  Setting back infrastructure will allow a wider corridor for channel migration and accessible floodplain area. Increased connectivity with the low-lying floodplain will lead to decreased channel velocities during high flows and dispersion of sediment across the floodplain.  Addition of LWD will initiate a geomorphic response resulting in bed scour and sorting of sediment, which forms critical habitat features (e.g., pools, cover, and spawning gravels).  Because the channel profile is controlled by man-made features and bedrock, the wood placements are not expected to significantly affect the channel grade. However, the ELJs will influence the development of additional pools and depositional areas in the plane-bed sections of the channel. In addition, large wood structures will promote development of a more complex channel network by splitting flow, initiating gravel bar and island development, and promoting channel migration within the reconnected floodplain area.

Biological Benefits:  Immediate biological benefits of the project include decreased instream velocities during high flows from better connectivity with the floodplain, and pool development and cover provided by the LWD placements. As the channel is able to establish a more complex plane-form through the reconnected floodplain, more diverse habitat areas will be available to increase the carrying capacity for juvenile salmonids. Deposition of sediment and formation of side channels will create additional spawning area. Over time, greater floodplain connectivity will also lead to a healthier riparian zone and, in turn, promote improved ecosystem processes and habitat function.