Co-authors: Mike Greiner and Brian Knoth
This summer, Idaho Fish and Game fisheries staff completed another river restoration project on the East Fork Potlatch River. This work continues a series of projects focused on improving juvenile steelhead habitat in the East Fork in recent years (Steelhead Habitat Restoration on the East Fork Potlatch River | IDFG; Making steelhead habitat complex | IDFG; Reflecting back on 2020: A year in review - close to 3 miles of fish habitat restored in upper Potlatch | IDFG). To date, IDFG and partners have improved nearly 5 miles of steelhead habitat in this drainage.
Much of the East Fork Potlatch River lacks the complex habitats (particularly large wood) that juvenile steelhead need to thrive. Large wood pieces in the stream scour deep pools for fish, provide cover and protection from predators, and create places to escape high stream flows. For this project, IDFG sourced the timber from the landowner and placed over 100 large pieces of wood in a 1-mile reach of the East Fork Potlatch River.
Another part of the project involved constructing riffles to help raise the water level in the stream to increase interaction with the floodplain. This helps the landscape act like a sponge and keep water in the system longer which can be critically important in drought years such as 2021. Constructed riffles also provide well-oxygenated, fast-flowing habitats preferable to juvenile steelhead. While this technique has been vetted by multiple restoration projects in Idaho and elsewhere, it has never been attempted in the Potlatch, making this an excellent opportunity to assess how well it works here.
These large wood projects are designed to mimic natural channel forming processes and to continue functioning long into the future and we are eager to see how they progress over time. Fish and Game staff continue to monitor how steelhead respond to restoration projects and are beginning to track steelhead throughout the East Fork with radio telemetry to see what habitat preferences they may have. Fish and Game expects the combined effect of these projects will result in more wild steelhead returning to the Potlatch River.