DWR: Test releases further erode Oroville Dam spillway

KCRA 3 News

Erosion on the Oroville Dam spillway got worse Wednesday after officials conducted test water releases. The increased erosion was expected, and engineers said they are pleased with the test results.

The California Department of Water Resources released about 20,000 cfs of water around 3:50 p.m. and kept the gates open for several hours. Officials said earlier that the test will further erode the spillway.  

“With the test flows, engineers will verify how much flow the spillway can handle,” the DWR said in a statement before the test. “The spillway is necessary to maintain reservoir operations, given the immediate forecast of continued rain for the next two days and also in preparation for the remaining runoff season.”

Parts of the right-side wall were lost and the hole in the middle of the spillway has gotten bigger, DWR officials said.

Crews were sent to the erosion site to take measurements.

The DWR closed the gates around noon Tuesday after a gaping hole was discovered in the spillway that leads to the Feather River. Officials were releasing water through the Hyatt Power Plant at 14,000 cfs when the dam’s gates were closed.

In the upcoming days, officials will continue to investigate ways to protect the spillway. They are also discussing whether to conduct more test water releases.

Currently, Lake Oroville is at 85 percent capacity –- 3 million acre-feet, which is well over the desired flood control conservation level, according to DWR statistics.

“Enough vacant space exists in the reservoir to capture the flow of the rains expected through Friday afternoon,” the DWR said in a statement. “The dam is sound, and no imminent threat to the public exists.”

Crews are also working to remove trees and debris from the area near the dam where water will naturally flow into in case an emergency spillway is needed.


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