Tucannon LWD Stream Habitat Restoration

The Washington Department of Fish and Wildlife (WDFW) placed 62 large wood (LW) structures between RM 42 and 44 of the Tucannon River on the WDFW Wooten Wildlife Area located in SE Washington in Columbia County. Their objectives were to increase in-stream habitat complexity and cover, maximize linkages between the river and its floodplain, increase the number and length of ephemeral and perennial channels, and improve riparian health and function. In 2005, the upper Tucannon Watershed experienced a major forest fire that burned large areas in and around the Tucannon River. As a result, some reaches of the river still lacked habitat complexity. This project assessed habitat complexity in three reaches along the Tucannon River, selected a priority reach for construction, and constructed a variety of large wood structures within the priority reach, both instream and on the floodplain. The project was designed to improve river habitat for ESA listed Spring Chinook, Steelhead, and Bull Trout by restoring the natural benefits that come from LW and Large Woody Debris (LWD).

Heavy equipment was used to build four engineered LW structures at the downstream end of the project reach that is in relatively close proximity to infrastructure. In addition, a helicopter installed 58 LW structures consisting of 291 individual trees throughout the project reach. The helicopter also placed over 500 smaller diameter “racking trees” in bundles, some placed by design, and others “salted” throughout the project reach. The smaller diameter material was designed to function as the course woody debris that accumulates on “key” tree pieces. Rocks and Boulders were used as ballast for some of the wood structures. The course debris provides cover and complexity to the stream. The project goal of having 2 key LWD elements per stream width was achieved.

A phased approach to riparian enhancement was planned for the project, however, project impacts were minimal and replanting was not needed.
Wood placement was completed in summer 2012. WDFW is monitoring the progress of the project and has pre- and post- project data (LiDAR, Low elevation photos, habitat assessment) to determine the rate and scope of changes in stream habitat resulting from this first phase of restoration. The data will be used to inform future phases. In addition, we are monitoring movement of the unanchored trees over time to assess project implementation success and improve our understanding of LW movement in the Tucannon River. We have placed 3 time lapse cameras on a few major structures to monitor project implementation success and to have imagery for future presentations and outreach. Additionally, beaver activity observed within the project area within 2 years of completion has been credited to habitat changes created by the project. WDFW is monitoring new den sites and food caches within the project reach and has found 2 new den site/food caches within the lower ½ of the project reach.

There are four main project objectives; Increase in-stream habitat complexity and cover, maximize linkages between the river and its floodplain, increase the number and length of ephemeral and perennial channels, and improve riparian health and function.