Presenter/s: Jennifer Weddle
Symposium Session: 2023 - 02 One Species to Restore them All: Beaver-based Watershed Restoration
Topics covered: adaptive management and monitoring, beavers, floodplain, lessons learned, and wetlands
The Triple Creek Wetland Restoration Project (the Project), located near Chesaw, WA, is intended to restore a functional and diverse ecosystem in the wetland formed near the confluences of Myers, Thorp, and Bolster Creeks. Historically, a series of beaver ponds on and near the project site slowed and stored water high in the watershed and supported diverse flora and fauna. In the late 1990s, a rain-on-snow flood event deeply incised Myers Creek (up to 15 feet). Much of the wetland drained, and the stream disconnected from the floodplain. Subsequently, the native willows and other riparian vegetation perished, beaver and other animals abandoned this habitat, and invasive reed canarygrass became the dominant vegetation in a simplified and degraded system. Starting in 2016, Okanogan Highlands Alliance (OHA) has led the effort to restore conditions that will allow ecological processes to establish and continue into the future. Process-based, low-tech restoration techniques, applied in concert with adaptive management encourage complexity, diversity, and resiliency in and near the stream. Ultimately, native species, including beaver, will take over long-term management of the system. In the stream, Beaver Dam Analogs (BDAs; wooden structures that mimic the form and function of natural beaver dams) have been installed, repaired and modified each year in order to aggrade the streambed and develop meanders. Monitoring has shown faster-than-expected changes, including: 24% increase in stream length over the ½ mile reach, and up to 7 ft of streambed aggradation. On the floodplain and, more recently, on the banks and BDAs themselves, more than 2,000 native plants have become established in about 30,000 ft2 of riparian area. Riparian plantings thrive thanks to: fencing and expanding enclosures as plants grow, mowing, weeding and mulching (and re-mulching) to give the plantings a competitive advantage over invasive reed canarygrass, and planting new areas as conditions allow. Ongoing efforts at Triple Creek are guided by a systematic cycle of adaptive management: monitoring of changes in and near the creek, evaluating needs and resources, and taking actions that maximize the interplay of geomorphic changes and biological changes. The Project has not only made tremendous progress towards restoring the habitat, it has also developed into a collaborative learning lab for restoration practitioners, local students, and the general public; the generous contributions of expertise, equipment, time, funding, and labor by partnering agencies, organizations and individuals have greatly expanded OHA’s capacity to do this work. The Project represents a long-term commitment to learning, adapting, and collaborating, with the end goal being a healthy, diverse, resilient wetland-stream system managed by nature’s most effective engineers: beavers.