*Submitted by Trout Unlimited
Once numbering in the hundreds of millions, beavers played a principal role in North America in how water moved through the landscape. Beaver dams and their hydrologic influence provide many essential ecosystem functions, including aquifer recharge, maintenance of complex instream habitat, buffering of fire impacts, riparian and wetland enhancement, floodplain connection, sediment capture, and moderation of stream flows and temperature. TU’s restoration techniques of mimicking beaver dams with Beaver Dam Analogs (BDAs) is growing because of its effectiveness, ease of construction, adaptability, and low cost. Combining the implementation of BDAs and beaver reintroduction at high-impact sites across the landscape has the exciting potential to enhance long-term water sustainability and habitat for fish and other aquatic species, particularly under changing climate conditions that have increased wildfire impacts and reducing late season flows, exacerbating one of the primary limiting factors to Upper Columbia salmonids including ESA-listed spring Chinook, steelhead, and bull trout. Since 2014, TU has developed a beaver-powered habitat and water restoration program in the Upper Columbia.
A recent ongoing project is located in Rock Island Creek in Douglas County. This project was initiated at the behest of landowners who remember the benefits beavers provided there historically. The purpose of this project was to create pools/ponds, induce channel meandering, reduce channel incision, and expand floodplain and wet meadow habitat in the Rock Island Creek Watershed
Phase I of the Beaver-Powered Restoration in Rock Island Creek Watershed project was implemented in the fall of 2021. Over the course of Phase I, TU installed 25 beaver dam analogs (BDAs) over a quarter-mile of stream. The Rock Island Creek watershed provides critical habitat for native redband rainbow trout/Upper Columbia steelhead (O. mykiss) and greater sage-grouse (C. urophasianus). Both Upper Columbia steelhead and greater sage-grouse are ESA listed species as federally threatened and Washington state endangered, respectively. Enhancing the riparian habitat for these vulnerable species is crucial, especially in the shrub-steppe ecosystem of Douglas County where water can be scarce.
Working with NRCS and USFWS, TU is planning for a second and third phase in Rock Island Creek. Phases II and III will be significantly larger than Phase I, with an upper range of 95-105 BDAs installed over a mile of stream. This will occur over two years of implementation in 2023 and 2024. The benefits produced by Phase II and Phase III will also be significantly greater. Beyond the habitat enhancement, an estimated range of 33-37 acre-feet of groundwater will be stored annually following implementation. Through storing water and raising the water table, BDAs increase the moisture of surrounding riparian vegetation, making these systems more resilient to wildfire and can serve as green fire breaks. This project is one step of many to restore natural processes to Rock Island Creek. With planning underway for future phases of this project, there is the opportunity to restore miles of the creek and its tributaries. Using low-tech process-based restoration practices, we are cost-effectively restoring habitat throughout the watershed.
Restoration work in Rock Island Creek is a great story about collaboration between federal and state agencies, private foundations along with local groups and conservation-minded landowners. This project is possible with the support from Microsoft, US Fish and Wildlife Service and Natural Resources Conservation Service..