Lower Yuba River project helps create safer home for salmon population, reduces flood risk
MARYSVILLE — A habitat restoration project in the lower Yuba River is complete. The project not only helps the local fish population but also those who live along the river's banks.
"The Hallwood Fish Habitat Project" restored the natural flow of the Yuba River after decades of collecting debris from hydraulic mining during the Gold Rush.
Aaron Zettler-Mann, executive director of the South Yuba River Citizens League, said he's proud of the project and the flood plain it's created.
"Prior to this project, really, the Yuba River was characterized by training walls, so massive piles roughly 80 feet tall of just aggregate," Zettler-Mann said.
Willie Whittlesey, general manager of the Yuba Water Agency, said these training walls within the Yuba Goldfields are where hundreds of millions of cubic yards of hydraulic mining sediment were deposited in the lower Yuba River through the early 1900s.
"All of the sands and gravel you see, these aren't natural reoccurring sands and gravels in the Lower Yuba River. They are the result of washing the hillsides away and extracting the gold, and then that sediment debris from 150 years has been making its way down to the Lower Yuba River," Whittlesey said.
The natural flow of the river along the north bank of the Lower Yuba River, downstream of the Daguerre Point Dam, was destroyed by gravel and debris over the years. That made the river flow faster and narrower, making it hard for Chinook salmon and Central Valley steelhead populations to survive.
"The amount of water in the river increases velocity, so those juvenile fish have a hard time staying in place and eating and growing up large. They get kind of flushed out pretty quickly, and there's not as much food available because there isn't as much water next to vegetation," Zettler-Mann said.
The nearly $12 million project broke ground in August 2019 and took four years of construction. It enhanced and restored 157 acres of floodplain habitat, including nearly two miles of restored side channels and alcoves and close to six miles of seasonally flooded side channels. This created areas where fish could hide, rest, eat and grow.
Now, with more room to spread out, California's salmon population can grow.
"They've got little places where they can hide behind rocks or in willows and sit and grow and continue to eat. And then the larger those fish are, the more likely they are to survive the trip out to the delta, the ocean and more likely to come back and spawn and continue to grow," Zettler-Mann said.
This project is a collaborative effort among many different organizations. Primary partners include the U.S. Fish and Wildlife Service (USFWS), California Natural Resources Agency, cbec eco engineering, Cramer Fish Sciences, South Yuba River Citizens League, Teichert, Western Aggregates, Wildlife Conservation Board and Yuba Water Agency.
Approximately 3.2 million cubic yards of sediment were removed throughout the project area. This will reduce flood risk by lowering water surface elevations during big storms and creating a bigger floodplain to reduce flood risk across Yuba County.
"If you can spread it out, it's going to slow down and the crest elevation of that water surface is going to drop which decreases flood risk downstream," Zettler-Mann said.
The larger floodplain can also add to groundwater storage in the years we have extra water.
"Because it's spread out and slower, the water moves into the groundwater storage a little bit faster and more water moves into that system, which means it is available later in the year as well," Zettler-Mann said.
The material removed from the river's banks was processed on-site at Teichert's facility nearby to be turned into aggregate within 24 hours for things like asphalt and cement for local road improvements.
This project is one of the first for Yuba Water Agency but not the last. Whittlesey said it will now be used as a template for other projects along the Lower Yuba River in the future.
"What we would like to do is replicate this project throughout the Lower Yuba River system with the partners we collaborated on on this project over the next 10 to 20 years until the entire river system is restored," Whittlesey said.
For more information on the Hallwood Fish Habitat Project, click here.