Video: Fremont Weir overtops for the first time with Big Notch Fish Passage Facility ready to operate

After a dry start, a series of late-December storms brought enough rain to swell the Sacramento River and overtop the Fremont Weir. While this is normal for the winter season, it’s the first time the Fremont Weir has overtopped with the Big Notch Project officially in operation.

"With changing water level conditions associated with storm events, DWR followed its protocol to close the gates at the Big Notch Fish Passage Facility. With the start of overtopping, DWR opened the gates at the Adult Fish Passage Facility,” said Steven Garcia, a DWR ecosystem engineer who operates the gates for both facilities. 

The Big Notch and Adult Fish Passage Facilities were built into the Fremont Weir with operable gates so that juvenile and adult salmon and sturgeon can pass between the Yolo Bypass and Sacramento River when certain flow conditions are met. The Fremont Weir is located about 15 miles northwest of Sacramento in Yolo County, and it’s one of five passive weirs on the Sacramento River. When the Sacramento River reaches 32 feet at the site, water spills over the concrete weir and flows into the Yolo Bypass. This provides important flood protection and creates floodplain habitat for juvenile salmon to feed before continuing their migration to the ocean. 

DWR captured video of the overtopping action at the Big Notch Project. 

To learn more about the weirs on the Sacramento River, please read our 100-year anniversary article.