Oroville Dam: Californian officials rush to drain lake as fresh wave of powerful storms roll in
Updated
Officials are racing to drain more water from a lake behind the battered Oroville Dam, as new storms begin rolling into Northern California.
Key points:
- Storms forecast for next week could add to dam levels but officials confident repairs will hold
- Reservoir has dropped 6 metres since reaching capacity on Sunday
- About 200,000 people have been told to return home after being evacuated
The three storms are expected to stretch into next week, and officials are testing the quick repairs made to damaged spillways that raised initial flood fears.
Forecasters said the first two storms could drop a total of 13 centimetres of rain in higher elevation — but the third storm, set to start as early as Monday (local time), could be more powerful.
"There is potential for several inches," National Weather Service forecaster Tom Dang said.
"It will be very wet."
Nonetheless, California Department of Water Resources chief Bill Croyle said water was draining at about four times the rate that it was flowing in and the repairs should hold at the nation's tallest dam.
About 2,830 cubic metres of water, enough to fill an Olympic-size swimming pool, was flowing from the reservoir each second.
Mr Croyle said work crews had made "great progress" cementing thousands of tonnes of rocks into holes in the spillways.
"We shouldn't see a bump in the reservoir [from the upcoming storms]," he said.
The reservoir has dropped six metres since it reached capacity on Sunday — Mr Croyle said officials hoped that it would fall 15 metres by Sunday.
But officials warned residents who have returned to their homes that the area downstream of the dam remained under an evacuation warning and they should be prepared to leave if the risk increases.
Some 200,000 people were allowed to return home on Tuesday after being ordered to evacuate on Sunday.
.jpg/8272298 "Evacuees return in California")
Butte County Sheriff Kory Honea said some homes in the evacuation zone had been burgled and deputies had made arrests.
He also called on private drone operators to refrain from flying their devices over the dam — private drones can interfere with the repair work, which involves helicopters, he said.
The 235-metre-tall dam is located in Oroville, a small Gold Rush-era town along the Feather River in the Sierra Nevada foothills.
The swollen lake reached its capacity over the weekend and spilled down an unpaved emergency spillway for nearly 40 hours, leaving it badly eroded.
The problem occurred six days after engineers discovered a growing hole in the dam's main concrete spillway.
Late Tuesday, President Donald Trump ordered federal authorities to help California recover from severe January storms — a disaster declaration that also assists state and local officials with the dam crisis.
AP
Topics: dams-and-reservoirs, disasters-and-accidents, united-states
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