Targeted in-stream restoration has been a pillar of our work since CoosWA was founded.
CoosWA began implementing in-stream restoration projects in the mid-1990s as a way to improve the quality and quantity of coho salmon habitat. These projects can be grouped into four general categories: wood placements, channel reconfiguration, fish passage, and sediment reduction. The first channel reconfiguration project for the organization was completed in 2008 while all other projects have been ongoing since the mid-1990’s. All in-stream projects are based on extensive analysis of aquatic habitat surveys and road inventory surveys conducted by our staff or partner agencies. While some techniques may overlap, each project type requires different procedures and tools in order to accomplish the desired restoration outcomes. Project work is contracted either through the Coos Watershed Association, the landowner (ex. Weyerhaeuser), or an independent operator. In-stream project work typically occurs from July 1st - September 15th during the “In-Water Work Window.” This window is set by the Oregon Department of Fish and Wildlife to protect aquatic habitat during critical spawning seasons and may be extended for special circumstances.
Large wood placements and constructed log jams are placed in stream channels to increase quantity and quality of spawning and rearing habitat for salmonids and other aquatic species. Large logs and boulders are placed within stream channels, altering water flow and preventing gravel and woody debris from washing downstream. Log placements also provide habitat complexity and cover for fish to avoid potential predators.
Channel reconfiguration, or re-meandering, consists of moving lowland streams that have been altered to run in a channelized ditch along one side of a valley for agricultural purposes back to their original path across the valley floor. Projects generally involve landowners who no longer want to use their field for agriculture but also landowners who want to help reconnect the floodplain and better drain their field while maintaining land for agricultural use.
Fish passage projects are designed to eliminate barriers for adult and juvenile salmonids to available spawning and rearing habitat upstream. Common projects include upgrading culverts (ex. hanging outlet, undersized) and tidegates (ex. failing, top hinged doors) that restrict passage to upstream habitat. Tidegate replacement is an increasingly important issue for watersheds such as Coos Bay as older infrastructure begins to fail in tidally influenced streams.
Road sediment reduction projects generally focus on areas of chronic and catastrophic sources of sediment that enter streams. An example of a chronic source would be a plugged, restricted, and/or failing culvert that is causing erosion over time. A failing culvert may lead to catastrophic failure in which a large amount of sediment enters the stream at once. Most sediment reduction projects focus on adding drainage features (culverts, etc.), maintenance of existing culverts, and increasing the size of stream crossing culverts that are undersized to reduce the possibility of plugging and complete failures.
From upland streams to the bay, the Coos Watershed Association works with private landowners and public agencies to ensure that stakeholder and environmental needs are being met. Because restoration strategies are dynamic and ever-improving, we make it a priority to build local partnerships and learn from every project we complete. Additionally, our in-stream work is only one facet of our restoration efforts and is often complemented by riparian stabilization (planting native tree/shrubs/grasses) and preventative education. The benefits from a single restoration project extend far beyond the project site itself, rippling through the watershed and increasing the quality of habitat for fish and humans alike.