OROVILLE, Calif. _ Even as rain began to fall Wednesday, California officials said the storm systems forecast over the next few days are not enough to test the integrity of the Oroville Dam or its two damaged spillways.
Bill Croyle, acting director of the Department of Water Resources, called the storms "fairly small" and the public "won't see a blip in the reservoir" levels, now dropping about 8 inches an hour.
Croyle said it is not the weather he is concerned about so much as the damage done to the dam's already compromised main spillway during days of sustained heavy releases of water.
"It's holding up really well," Croyle said, but continued mass water releases could be causing hidden damage to the rocky subsurface adjacent to the concrete chute.
A swarm of trucks and helicopters dumped 1,200 tons of material per hour onto the eroded hillside that formed the dam's emergency spillway. One quarry worked around the clock to mine boulders as heavy as 6 tons. An army of workers mixed concrete slurry to help seal the rocks in place.
At the main spillway, a different and riskier operation was underway: Despite a large hole in the concrete chute, officials have been sending a massive amount of the swollen reservoir's water down the chute to the Feather River in a desperate attempt to reduce the lake's level.
The idea is to get the reservoir's water level low enough that it can take in rain from an upcoming series of storms without reaching capacity. If the reservoir filled up again, water would automatically flow down the emergency spillway, which on Sunday appeared to be nearing collapse, forcing the evacuation of more than 100,000 people downstream.
Croyle said there are plans to begin to taper off the water discharges at the end of the week.
Data from the Department of Water Resources shows Shasta Dam discharges began to be sharply increased on Feb. 10 and have increased substantially every day since that.
Federal emergency officials and the Trump administration approved Gov. Jerry Brown 's requests for presidential disaster declarations for both the Oroville dam and the response to major winter storms in January, including mudslides and power outages.
"I want to thank FEMA for moving quickly to approve our requests," Brown said in a statement from his office.
At a news briefing Tuesday, White House press secretary Sean Spicer said President Donald Trump has been "keeping a close eye" on the situation in Oroville.
"The situation is a textbook example of why we need to pursue a major infrastructure package in Congress," Spicer said. "Dams, bridges, roads and all ports around the country have fallen into disrepair."
