Methow Beaver Project - Beavers and Anadromy

WA RCO Project Award #18-1856R supported Methow Beaver Project’s (MBP) work to implement and complete project objectives outlined in the grant agreement. MBP activities included: implementing and evaluating habitat changes and fish utilization where MBP translocated beavers and released them in anadromous habitat; conducting repeated observation of beavers actively impounding flows in anadromous habitats, including salmon restoration project sites; constructing small bank anchored woody structures, called post-assisted log structures (PALS), to aid in pond development where beavers were not present. A total of 54 beavers were introduced. The PALS were constructed to ensure salmon passage in anadromous habitat areas. This project consisted of a watershed approach to beaver co-existence and relocation to support salmon habitat. As a watershed approach, it is considered one worksite

MBP requested two scope changes during the performance period to add Beaver & Salmon Coexistence Outreach and Education (Sept 2019) and Beaver Coexistence Strategies (May 2020). These scope changes were reviewed and approved by our grant manager, Marc Duboiski.

A no cost time extension was also approved in July 2020 to extend the performance period as a result of challenges related to the Covid-19 shutdown and rippling delays to all aspects of restoration, coexistence and outreach. PCSRF 2015 and 2016 were spent within the award period.

WORK COMPLETED BY SITE & TASK:

TWISP RIVER FLOODPLAIN (Parcel # 3321100033)
• Installed 22 micro-PALS (post assisted log structures) in small side channel. Beavers expanded on micro-PALS but did not establish. Increased instream wood density by 25%. Increased the number of pools by 4x.
• Installed 18 non-channel spanning PALS in three complexes of structures in 2 large side channel. Increased instream wood density and habitat complexity by 38%. Increased the number of pools, riffles and runs by 5x.
• Increased substrate complexity from primarily uniform and embedded cobble and small boulder pre-restoration to dynamic sediment and gravel deposition and transport zones
• Released two beavers in the larger upstream side channel in August 2020, built dams but did not establish. Released a single beaver September 2021. 4 new beaver dams were under construction by mid-October 2021. Beavers now established at site.
• Wrapped 26 mature riparian trees (primarily cottonwoods P. trichocarpa) to deter beaver felling of larger stream shading trees.
• Hosted University of WA Wetland Ecology class – May 2022
• Hosted Whitman College Semester in the West – August 2022
• Assessed beaver/salmonid coexistence in the site documenting one or more of the following variables: habitat unit complexity, substrate, discharge, water quality, and salmon and beaver utilization (July 2020 – March 2023).
• Reconnected >3 acres of relic floodplain to Twisp River annual flows.
• Expanded hydraulic refugia habitat availability to juvenile salmonids by 8 weeks between early April and mid-June during average seasonal high flows.
• Expanded summer rearing and overwintering habitat for juvenile salmonids.
• Snorkel surveys confirmed fish utilization increased each year after PALS restoration and beaver establishment.

SILVER SIDE CHANNEL (Parcel # 3322340213) – Methow River downstream of Twisp
• Wrapped 33 mature riparian trees (primarily cottonwoods P. trichocarpa) to deter beaver felling of larger stream shading trees.
• Installed a flow device to control surface water elevation (SWE) and a fish passage device (FPD) to allow on-site management of beavers and better accommodate downstream juvenile fish passage in all seasons.
• Lowered the beaver dam height to increase hydroperiod of backwater connection from the Methow.
• Conducted continuous quarterly efficacy monitoring, all working well
• Fish utilization increased each year after beaver coexistence implemented

To restore side channel and off channel habitat through beaver reestablishment, low tech process-based restoration, and beaver coexistence strategies that improve stream structure, slow and spread water, increase habitat quantity and complexity, and allow beavers to be managed in-place. These strategies result in improved hydraulic refugia, summer rearing, and overwintering habitat that benefits ESA-listed spring Chinook and steelhead.