Hallwood Side Channel and Floodplain Restoration Project
The Hallwood Side Channel and Floodplain Restoration Project, funded by the U.S. Fish and Wildlife Service, will improve habitat in the Lower Yuba River for Chinook salmon and steelhead trout. Other project partners include Yuba Water Agency, cbec eco-engineering, Cramer Fish Sciences, South Yuba River Citizens League (SYRCL), Teichert Materials, and Western Aggregates.
Background: In the project area, the Yuba River is constrained by tall linear cobble embankments called training walls, which were constructed in the early 1900s by hydraulic dredges following the Gold Rush. These training walls are within the highly modified Yuba Goldfields setting where hundreds of millions of cubic yards of hydraulic mining sediment was deposited in the lower Yuba River through the early 1900s. The area was subsequently dredged multiple times, creating significant impacts for the natural flow of the river and the floodplain. A large training wall in the middle of the river, known as the Middle Training Wall, runs more than 2 miles along the length of the project
The project design is based on the premise that restoration of natural river and floodplain processes, including the removal of large portions of the Middle Training Wall, will create a healthier, more natural, and therefore, more productive river. Improvements will enhance up to 157 acres of seasonally inundated riparian floodplain, approximately 1.7 miles of perennial side channels, and approximately 6.1 miles of seasonally inundated side channels, alcoves, and swales. Enhancements will be made through land surface changes, riparian planting, and placement of large woody material embedded to simulate a more natural river at key locations. The total project cost is estimated to be $6 million. Funding has been provided by USFWS grants and Yuba Water Agency.
Construction is currently in Phase 3 of 4.
- Portions of the Middle Training Wall continue to be removed bit by bit
- Enhancing floodplain and seasonally inundated side channel habitat is the focus of this phase
- As a part of this phase, Large Woody Material (trees with branches, some with root wads still intact) will be strategically placed in the floodplain area. These features function as juvenile salmonid habitat by creating slower moving water conditions where juveniles can congregate as they feed and grow
- Biological monitoring efforts continue in off-channel habitat to measure ecosystem benefits from Phases 1 and 2.
- New beaver activity continues to be observed
- This creates new habitat for fish and fosters moist conditions for naturally recruited and planted vegetation in summer months
