Officials had hoped to lower the lake's level by 50 feet in advance of new rains, but fell significantly short of that goal, only reaching a 36-foot reduction by Thursday, according to local NBC News affiliate KCRA.
Butte County Sheriff Kory Honea said Wednesday that he didn't know exactly how many arrests deputies have made.
Oroville Dam is the highest in the nation, and its reservoir is the second-largest in the state.
Around 8 a.m. Thursday, officials began slowing the flow out of the reservoir's damaged but still-functioning primary spillway that has been releasing 100,000 cubic feet of water per second since evacuation orders first went out around 4:30 p.m. Sunday. The dam itself is to the right, the concrete overfloss spillway in the center, left of it is the emergency overflow.
Dump trucks and helicopters have dropped thousands of tons of rocks and sandbags to shore up the spillways at Oroville Dam and avoid what officials had warned could be a catastrophic failure and flood downstream. Nearly 200,000 people remain under evacuation order.
Public Utilities Director Halla Razak met with reporters at Lake Miramar, where an earthen dam completed in 1960 holds 100,000 acre-feet of water.
As for our water supply, with all the rain expected in California over the next few days, if the Oroville Reservoir does fail, we'll be fine in San Diego. The reservoirs are now filled to just above 50 percent of their capacity, Razak said. But the storm was looking colder than initially projected, meaning less rain and less runoff than last week's storms.