Tucannon Ranch River Reach Design/Feasibility

This project developed a comprehensive plan to restore salmonid habitat along 3.8 miles of the Tucannon River from RM 0.7 to 4.5 (idenified as Reach 2 by Anchor QEA, 2011). The project also partially funded a LIDAR survey and analysis of 51 miles of the Tucannon River, beginning at the rivers mouth. Dikes within the town of Starbuck, just above the project area for the comprehensive plan, confine the river resulting in enhanced bedload movement. The resulting bedload buildup down river led to chronic flooding of agricultural fields and short-term filling of critical salmon habitat which adversely impacted irrigation infrastructure. Understanding the channel processes that are causing these circumstances is critical to successful restoration efforts. This project identified alternatives to preserve the interests of both fish and farmers. The reach is utilized by 4 ESA listed species, including Fall Chinook (spawning & rearing); Spring Chinook (migration); Steelhead (spawning, rearing, migration and overwintering); and bull trout (overwintering & migration). This project developed a long-term strategy to improve salmon habitat and consider other stakeholder interests, including flood management and agricultural productivity. Management activities identified thru this project included instream habitat enhancement by LWD placement, enhancement/stabilization of floodplain function, off-set dikes and/or conservation easements. Project deliverables included: conceptual reach design, 30% design from one developed concept, assessment report documenting LIDAR images, flow patterns, hydrology, cross-section, & priority actions.
The Tucannon River is primarily a single thread channel that meanders through a relatively low lying, vegetated riparian corridor. Although historically the floodplain and riparian area were likely more expansive and complex, the present day condition of the river is limited by human infrastructure that controls the channel position. Presently there are multiple rock weirs, barbs, levees and spoil pile berms that control the grade, limit channel migration and interrupt the natural floodplain process. Additional infrastructure such as buildings and agricultural land irrigated by pivot systems, physically limit the extent of restoration possibilities.

The goal of the project is to increase/improve information to help select projects that have a high certainty and benefit. The objective of the project is to determine project siting, feasibility, design, or implementation.