The Mendocino Land Trust is fortunate to have staff that have expertise in salmon restoration work. In spring 2021, MLT Conservation Manager Nicolet Houtz took the time to explain a few of the ways conservation leaders like her work to improve salmon habitat.
One way is by doing “in-stream habitat restoration.” In this kind of project, large woody debris is placed in streams that have been altered by past human activities to improve salmon habitat. When done correctly, the added logs slow the flow of water allowing adult fish an easier journey upstream and better areas for young fish to develop into adults. The woody debris gives fish places to hide from predators and lowers water temperature by creating shaded spaces. Additionally, the logs trap leaves and other organic material that flow into the stream creating nutrients and habitat for insects and invertebrates, which in turn become food for the fish. Over time, the water flowing over logs can form deep pools which can sustain fish during periods of low water or drought.
Project Highlight: Hare Creek and Bunker Gulch—Goodbye roads, hello woody debris!
In 2019, Houtz coordinated salmon habitat restoration projects along Hare Creek and Bunker Gulch (a tributary to Hare Creek). “The timing of the stream restoration projects coincided with decommissioning two old logging roads, which were practically perched on the stream bank,” Houtz said. “This required coordinating with CCC crews who were in the stream, and heavy equipment operators working to reconnect the stream bank by removing the road. It was difficult coordinating the two projects at once, but they ended up complementing each other."
Houtz said road decommissioning is important because “one of the largest causes of the declining health of water quality and salmon health is the increase of fine sediment in waterways.” Runoff from rains coming down roads picks up a lot of sediment that winds up in creeks. This can drastically reduce water quality. Then fish pull sediment-laden water through their gills, it has serious health effects and greatly increases fish mortality. Road decommissioning is done according to strict protocols, with barriers placed at the edge of the project area to ensure sediment does not enter creeks. After the road decommissioning was complete, Houtz and other MLT staff and interns planted redwood saplings in the cleared areas, thanks to funding from Sonoma Clean Power. This allowed the disturbed area to again become forested habitat. As the trees grow, their roots hold sediment in place and keep it out of streams to ensure improved water quality.
Stream crossing replacement projects are another way to improve salmon habitat. Culverts that channel the passage of water under our roads and railroad trestles are critical to our infrastructure - but they have to be done carefully and maintained. Culverts installed in the past were often undersized and became clogged with debris, blocking the passage of salmon. Many culverts were installed with too big of a drop on the downstream side. This becomes a major impediment when salmon are headed upstream to spawn—they cannot make those jumps. The Mendocino Land Trust has coordinated culvert replacement projects along tributaries to Big River. Trout Unlimited completed a large project along the Noyo River in 2020 which included replacing two culverts in MLT’s Noyo River Redwoods preserve.
The Land Trust has also been involved in small dam removal projects. In the past, dams were often installed to ensure a consistent water source for people or cattle. In most cases, however, dams also limit salmon migration. Several years ago, the Mendocino Land Trust did a project to remove the Parlin Creek dam in the Noyo River watershed.
Houtz is excited that two salmon habitat restoration proposals were selected for funding in 2021. One is to improve salmon habitat in Bear Gulch, a tributary to the South Fork Noyo, and a coho-bearing stream. The second funded project is to design a new crossing on Chamberlain Creek to replace a partial barrier to salmon migration. Much of the funding comes from the California Department of Fish and Wildlife’s Fisheries Restoration Grant Program.