Huge California reservoir nearing capacity; State warns of possible overflow, activation of spillway

Visitors to the Oroville Dam area may also notice small amounts of water flowing from drains.Photo byCalifornia DWR

Lake Oroville, one of California's key reservoirs, is currently nearing full capacity, reaching 99% of its total capacity, as reported by the California Department of Water Resources (CA DWR). This figure represents 127% of the historical average for this time of year, prompting officials to issue warnings regarding potential spillway activity.

As the lake edges closer to its maximum capacity, the CA DWR is cautioning the public about the possibility of waves splashing over the crest of the emergency spillway during windy conditions. Visitors to the Oroville Dam area may also notice small amounts of water flowing from drains built into the emergency spillway. Despite these observations, authorities assure that both the dam and emergency spillway are functioning as intended.

"In April, DWR decreased total releases from Lake Oroville to account for reduced inflows into the reservoir, while optimizing storage for water supply, recreation, and fish and wildlife enhancement," stated the CA DWR in their press release on Friday. "DWR coordinates closely with the U.S. Army Corps of Engineers and other water operators to maintain balance throughout the water system, adjusting releases as necessary."

Lake Oroville's current water level stands at 3,490,227 acre-feet (AF), significantly higher than the average for this time of year, which is 2,741,551 AF. In comparison, at the same time last year, the lake was at 55% of its total capacity, with 1,931,121 AF of water.

Presently, total releases to the Feather River amount to 5,500 cubic feet per second (cfs), with 650 cfs routed down the Low Flow Channel through the City of Oroville. An additional 4,850 cfs is being released from the Thermalito Afterbay River Outlet, located 5 miles downstream from Oroville. Authorities note that total Feather River releases may be increased over the weekend to accommodate higher reservoir inflows from weekend precipitation.

Residents and interested parties are encouraged to stay informed about reservoir levels by accessing the California Department of Water Resources' California Data Exchange Center at www.cdec.water.ca.gov.