Restoring Pataha Creek with Simulated Beaver Dams

Pomeroy Conservation District installed a series of beaver dam analog (BDA) complexes to improve habitat diversity, reduce channel incision, and reconnect the floodplain in Pataha Creek. BDA complexes are usually comprised of a primary dam, a secondary dam located downstream of the primary dam, and post-assisted log (PAL) structures or large wood located upstream of the primary dam. The secondary dam is used to support the primary dam by backing water up to reduce the potential for undercutting the primary dam. PAL structures or large wood are designed to promote local scour that provides a source of sediment to accumulate behind the primary dam and, thus, facilitates floodplain connection and side channel development.
The Pataha Working with Beavers project was implemented in two phases. Phase I included using the Beaver Restoration Assessment Tool (http://etal.usu.edu/BRAT/) to assess the potential of the Tucannon River watershed to support dam building beavers, and installing eight trial BDAs in Pataha Creek; both were completed in 2015 (Bennett et al. 2015). Phase II included developing and implementing a comprehensive design using BDA complexes to restore 2 km of Pataha Creek in 2016, based on the results of the assessment and trial. In phase II, we constructed 58 structures - 25 BDAs and 33 PALS.
The project is intended to help restore more ecologically based stream processes that are promoted by beavers (e.g., increased aggradation, reduced sediment and erosion, increased habitat diversity) and demonstrate a cost-effective restoration method that may be applicable to many areas in southeast Washington. The target species are Snake River ESU steelhead with potential benefits for Chinook Salmon and Bull Trout.

This is a pilot project to determine if beaver dam analogs and post-assisted log structures can be used to decrease incision, increase habitat complexity, and reduce the extent of reed canary grass in Pataha Creek for the benefit of steelhead, Chinook, and bull trout populations. Lessons learned from this project will help determine how best to restore streams like Pataha Creek in se Washington which are very common.