Project is underway
The migration of adult Chinook salmon into the Colusa Basin Drain during periods of high runoff which acts as an attractant, where they are trapped, was widely reported for many years by agency personnel and stakeholder groups. Once in the drain, the fish die without successfully spawning.
In 2012 an estimated 600 adult winter-run were trapped in the drain. A massive recovery effort was undertaken but the results were doubtful. Development of a blocking barrier or some other way to keep the fish out of the drain became a high priority. Fisheries scientist Dave Vogel developed an engineered slanted screen proposal and Reclamation District 108 stepped forward to fund and implement it. State and federal agencies approved the design and construction was started in September of 2015. The large project was completed in late November of 2015. Further structural problems emerged after the wet winter of 2017. It’s not clear if they’ve been entirely addressed and fixed.
In addition, the problem of adult salmon returning to spawn by way of the Yolo Bypass is being addressed. A capture facility was built in the Bypass at Wallace Weir to trap adult fish and allow their transport back to the Sacramento River. The efficacy of this facility is still being evaluated.