Thousands of tons of gravel is being laid in the American River this month, re-establishing a crucial spawning area for hundreds of native salmon and steelhead trout.
On Friday, crews used rocks and stones dredged up from the river more than a century ago during Gold Rush to create opportunities to find shelter and food for the fish at Sailor Bay.
The project will ultimately add 14,000 tons from the floodplain to the flowing water near Fair Oaks before Chinook salmon begin to make the grueling trek from the Pacific Ocean up to the American River starting in October.
Female salmon use the loose stone to will build redds, a kind of nest, to deposit their eggs. In 2009, when the Sailor Bar spawning habitat was last restored using the same method, 122 redds were spotted in the area afterward. Last year, there were no redds along the riverbed, with most of the gravel having been washed away, according to conservationists.
Because of developments along the river such as Nimbus Dam and Folsom Dam, sediment and debris that would otherwise settle along the river and replace old gravel are blocked, said Tom Gohring, executive director of the Sacramento Water Forum, a coalition of environmental, governmental and business groups.
“It’s also blocking salmon species from reaching some of their prehistoric spawning grounds,” Gohring said. “In some sense we’re recreating spawning and rearing areas on the valley floor that they don’t have access to anymore up in the headwaters.”
Also part of the project is a new side channel through the bar that’s parallel to the river, creating a protected area for juvenile fish to grow. The shallow, slower moving water will allow insects and vegetation to flourish for feeding, while also allowing the fish hiding spots, keeping larger predators from eating them.
“We don’t just need maternity wards, which is this in-river spawning gravel, but we also need nurseries,” said Lilly Allen, a scientist with the Water Forum.
“They’ll need some cover and some food. And we want to grow them larger so that when they make it through the Sacramento River, into the Delta and out to the ocean they are a robust healthy fish,” she said.
In the last ten years, spawning gravel restoration projects have occurred at Nimbus Basin, Sacramento Bar and the River Bend area of the American. Future additional restoration sites over the next 15 years are planned at El Manto Access, Sunrise Recreation area and Ancil Hoffman Park, according to the Water Forum.
The Sailor Bay project costs about $1 million, paid for largely through the federal Central Valley Project Improvement Act, as well as some local funding, according to Richard Welsh, an acting deputy regional director with the U.S. Bureau of Reclamation.