Salmon Return to Auburn Ravine After the Hemphill Dam Comes Down
The Hemphill Diversion Dam blocked salmon for nearly a century. Now it is gone, and six miles of spawning gravel are open again.
American River Canyon Alliance
For nearly a century the Hemphill Diversion Dam was the wall. Built in the 1930s near Lincoln, it pooled Auburn Ravine and fed the canals while stopping fish cold. Placer County Conservation Program director Gregg McKenzie called it the most significant barrier to salmon and steelhead in the county.
That wall is down. In fall 2022 the dam was removed and replaced with a roughened rock ramp of gravel and boulders. Water still flows to farms and ranches. Fish now swim over it. Biologist James Haufler put the change plainly: the old structure blocked about 90 percent of fish, and the new one passes about 90 percent.
The result is measurable. Six miles of prime spawning habitat reopened above the site. On November 22, 2025, a survey counted 42 live salmon and four redds in newly reachable water. Earlier eDNA sampling by ECORP in 2023 and 2024 detected Chinook and Pacific lamprey upstream of the old diversion.
The project pulled together Nevada Irrigation District, the City of Lincoln, Placer County Conservation Program, ECORP, Friends of Auburn Ravine, California Department of Fish and Wildlife, NOAA Fisheries, and Save Auburn Ravine Salmon and Steelhead.
SARSAS keeps working upstream. It installed dual cone fish screens on the Pleasant Grove Canal in 2016 and helped open passage at the Lincoln gauging station. Its North Ravine effort restores four miles of steelhead tributary and needs volunteers. Contact coordinator Robert Hane at 530-885-3005, or reach the citizen science program through Bob Johnson at 530-262-7036.