The U.S. Army Corps of Engineers has unveiled an environmental safeguard to protect endangered fish as part of the Sacramento Weir Widening Project. The system aims to prevent thousands of salmon and sturgeon from becoming stranded or blocked from reaching spawning grounds during flood events.
The fish passage, developed by the Sacramento District, is an innovative 1.6-mile “double hybrid technical fishway” connecting the Sacramento River to Tule Canal, which runs through the Yolo Bypass west of Sacramento. Unlike typical fish ladders, this system features two parallel channels designed for fish up to 10 feet long. Earlier designs with single-channel fish ladders were rejected after hydraulic modeling showed water would move too fast during floods for fish to navigate.
“This structure serves as a fish highway from the Sacramento River to the Tule Canal, and vice versa,” said Robert Chase, senior fisheries biologist who recently retired from the U.S. Army Corps of Engineers Sacramento District. “It’s about getting fish back on track where they need to go.” Without this connection, fish would swim up the bypass with a good chance of stranding or potentially dying.
According to Chase, the fish passage is accessible after flood events when the fish passage gates are opened for water passage. These high-water events typically occur between December and March, coinciding with juvenile salmon migrating downstream while adult sturgeon move upstream to spawning grounds—an ecological cycle previously disrupted by existing infrastructure. A key component—the bypass transport channel—is already operational and has demonstrated remarkable effectiveness. During a recent event, this channel allowed juvenile Chinook salmon that were stuck in the basin to flush out, drastically reducing fish stranding compared to previous years when thousands of salmon would have been trapped…