Officials are lowering the gates of the Sacramento Weir, effectively corking a massive gush of water that helped flood the Yolo Bypass west of Sacramento.
After a deluge of heavy rains, crews on Jan. 10 lifted the gates on the flood release structure near downtown Sacramento. It was the first time since 2006 that the river rose high enough to open the structure.
The weir acts as a flood-release valve to flush excess water from the Sacramento River system into the Yolo Bypass floodplain, keeping Sacramento and towns along the river from getting swamped.
State officials estimate that since the gates were open, around 800,000 acre feet of water passed through the structure. That’s almost enough to flood a completely dry Folsom Lake, which has a 977,000 acre-foot capacity.
In the coming days, crews will close around 10 to 12 of the weir gates each day until water stops flowing from the structure, said Doug Carlson, a spokesman for the Department of Water Resources.
The bypass will still have some water flowing into it.
The Fremont Weir near Woodland is engineered to automatically dump water into the northern bypass when the Sacramento River reaches a certain height. It’s projected to keep flowing into the bypass through at least the weekend.