Friday January 13, 2023
CapRadio —
If you’re driving north of downtown Sacramento on Highway 5 or 99, you may notice flooding in off-road areas that seem a little unusual. What you’re likely seeing is one of many weirs in the Sacramento region that help prevent flooding during intense weather. Since New Year’s Eve, many weirs in the area have diverted water that would have otherwise overflowed out of the American, Sacramento and Feather rivers, among others.
Unlike dams or levees, weirs aren’t created to store water or hold it back. Instead, weirs divert water. When a river begins to overflow, like it might during a storm with a lot of rain, a weir carries that excess water from the river elsewhere.
Aside from the Sacramento Weir, which has a gate, most weirs don’t require anyone to operate them, passively diverting flow only after water levels in a river rise enough to pass over the weir structure.
CapRadio spoke to Todd Bernardy, a manager for the Division of Flood Management with the state’s Department of Water Resources, to learn more about the history of weirs in our area, and how they operate.