Lake Oroville is nearly at capacity. Despite the wet weather moving through the region, officials with the Department of Water Resources say there is still plenty of room for runoff.
The lake’s level was at 889 feet Thursday afternoon, or 95 percent capacity. There is still about 11 feet of space left before water would begin to overtop the dam, but officials don’t plan on letting it get to that point.
Oroville had major renovation work done to its main spillway and emergency spillway over the past couple years following a scare that sent 10s of thousands of downriver residents scurrying for higher ground. The catastrophic failure that was feared never happened.
“At an elevation of 889 (feet), there’s about 120,000 acre-feet of storage remaining in the reservoir,” said Erin Mellon, assistant director of public affairs for DWR. “It’s common for Lake Oroville to stay relatively full during the summer months after an above-average water year like the one we experienced in 2018/19.”
For comparison, Mellon said the reservoir was filled to near-capacity or capacity – an elevation between 898 and 900 feet – for the entire month of July in 2011, which provided optimal recreation opportunities and refilled California’s water bank account to help the state get through the tail-end of a prolonged drought.
With a reconstructed spillway to rely on this year, DWR plans on letting the lake’s elevation get up to 899 feet.
One of the reasons DWR isn’t concerned about the current storm system is because it has been about 10 to 20 degrees colder than normal for this time of year, which means most precipitation will fall as snow in the upper elevations, limiting inflows to the reservoir. The warmer the storm, the more snowmelt and higher inflows into a particular watershed.
Mellon said the Feather River watershed experienced its peak snowmelt runoff during the last week of April.
“Our work with NASA shows that most of the Feather River watershed is snow free and that the remaining snowpack is limited to the higher elevations in the watershed,” she said. “…We continually monitor the conditions and the forecasts and make operational adjustments in real time based on the latest data.”
There aren’t any plans currently to use the spillway, but if that changes, Mellon said, DWR will notify the public ahead of time.
“Just because we’re not using the spillway doesn’t mean we’re not releasing water from the reservoir,” she said, referring to the Hyatt Powerplant, which gives DWR another means to release water. “Current releases from the reservoir will be about 13,000 cubic feet of water per second (on Friday). If we need to use the spillway again this year to manage inflows and lake levels, it is ready.”