Update 2/8/2016: Engineers at Lake Oroville are currently testing the strength of an eroding spillway by allowing the release of 20,000 cubic feet of water per second to run down it for a couple of hours.
They say the test flow will give them a sense of how much water the spillway can withstand.
The Department of Water Resources shut the spillway yesterday to investigate a growing hole that had appeared in the concrete.
Reports put it at 200 feet long and 30 feet deep.
A spokesperson for the department says there is no threat to those living downstream on the Feather River, as the spillway is not directly connected to the dam.
DWR says an emergency spillway would allow water to naturally flow from the reservoir should it reach peak capacity.
As of this afternoon, Oroville was nearly 86 percent full.
DWR says there is enough remaining room to capture the flow generated by storm runoff through Friday afternoon.
Original: Concrete erosion on the Lake Oroville spillway has reduced the amount of water being released from the lake during a week of heavy rains.
The Department of Water Resources says it's currently assessing the situation to see how repairs can be made.
"The dam's integrity is sound. The spillway, it's important to note, is not actually a part of the dam itself, so there is no imminent danger to the dam or to people or infrastructure below the dam," says DWR Spokesman Ted Thomas.
Water can still be released from the lake, primarily through the adjacent power plant.
Thomas says the lake is also intentionally kept low this time of year to allow for heavy runoff.