A decade ago, SYRCL began the first project in the Lower Yuba River to restore salmon habitat. Between 2011 and 2012 SYRCL planted nearly 6,500 willow and cottonwood cuttings across 5 acres to improve the floodplain habitat that fish use during high flow periods as refuge from swift-moving water in the main river channel.
One goal of this project was to restore the ecosystem functions that a mature riparian forest provides, including improving fish habitat by providing shade and cover and increasing food availability. The willows and cottonwood also help to trap fine sediment that would otherwise end up downriver, while creating geomorphic and hydraulic complexity on the floodplain.
The planting process was quite different than using a simple shovel to dig a hole in the ground. Large excavators were necessary to move through the gravel to reach groundwater depth. Without access to groundwater, the plants would quickly perish.
Did the restoration work?
Yes! Below, you can see how the trees planted were able to trap sediment during a flood event. The first image (top left) shows the plantings prior to the flood. The second image (top right) depicts the water at its highest level, during which time the plants were completely submerged. In the third image (bottom left), one can see that sediment from the event was trapped by the established plantings. The final image (bottom right) shows the plantings leafing out just a couple months later in the spring.
On average, 50% of the trees planted at the project site of survived. What offers even more hope is the fact that the surviving willows that trapped sediment are creating more habitat for the riparian trees. This evidence of young tree recruitment means that the ecosystem is truly recovering.
The Hammon Bar Restoration Project success has inspired other restoration projects on the Lower Yuba River and provided hope that vision, collaboration, and hard work can restore crucial salmon habitat.
If you would like to find out more about the work we are doing to restore fish habitat in the Lower Yuba River, you can click here.