USA TODAY International Edition
OROVILLE DAM UNDER SIEGE
Tens of thousands in Calif. have fled, and new storms are approaching
Though the level of California’s second- largest reservoir has dropped about 31⁄ feet, 2 two storms are expected to hit the state this week and bring 2 to 6 inches of rain to Oroville, where the concrete spillway at Oroville Dam has been crumbling since last Tuesday.
Forecasters predicted a moderate storm Wednesday and a “really big and strong” storm Friday, says Brandt Maxwell, National Weather Service meteorologist. An additional 8 inches of rain could fall in the mountains before draining into Lake Oroville, and that would increase the flow of water at the dam where severe erosion could drop the top of the spillway enough for water to pour out uncontrolled.
An emergency earthen spillway with a concrete lip was eroding so severely Sunday that officials warned a 30- foot wall of water could be unleashed on Oroville and other towns along the Feather River. At least 188,000 residents were ordered to evacuate the area, about 150 miles northeast of San Francisco.
State water officials worked to reduce the lake’s water level by 50 feet ahead of the storms. That would allow more room for runoff and allow authorities to stop using the spillways entirely so
If they haven’t found something really good ... things are going to go downhill further.” Brandt Maxwell, National Weather Service
they could repair the crumbling main spillway.
State water experts don’t know why the emergency spillway eroded after water was sent down it Sunday for the first time in the dam’s almost- 50- year history, says California’s acting director of water resources, Bill Croyle.
“I’m not sure anything went wrong,” he says. “That system has been installed since the early 1960s. It’s been monitored, but I’m not sure what caused the damage itself. It’s designed for higher flows.”
Sunday, the mandatory evacuation order below Oroville Dam triggered a chaotic exodus, filling highways as evacuees headed north and west toward higher ground. An emergency shelter at the Silver Dollar Fairgrounds, 24 miles north, filled within hours. Several other shelters were established.
The emergency spillway had never been activated since the dam was topped off in October 1967 but was pressed into service because Oroville Dam’s main concrete spillway developed a 200foot- long, 30- foot- deep hole Tuesday that continued to erode. Both spillways sit off to the side of the dam itself. The main structure remained sound.
In an effort to preserve the concrete lip of the emergency spillway, operators with the California Department of Water Resources doubled flows Sunday into the main spillway despite its bottom being largely washed out.
As 100,000 cubic feet of water left Lake Oroville each second, the lake level dropped quickly. That relieved pressure on the emergency chute, but it chewed more concrete from the bed of the main spillway.
The most recent inspection of the Oroville Dam’s main spillway didn’t include a close examination, according to a California safety report released in July.
“A visual inspection from some distance indicated no visible signs of concrete deficiencies,” the report from the California Division of Safety of Dams said. It was unclear why the spillway was not more closely inspected, Chris Orrock, a division spokesman, said last week.
Officials hoped that increased use of the main spillway would save the emergency backup chute and that efforts to backfill the auxiliary spillway’s holes with bags of rocks could shore it up Monday. California’s National Guard said it would provide eight helicopters to help with reconstruction.
Butte County Sheriff Kory Honea says he had no choice but to order an evacuation.
“I didn’t have the luxury of waiting to see if all was OK. We need to get people moving quickly and to save lives in case the worst case came to fruition,” Honea says. “This is a very dynamic situation. This is a situation that could change very, very rapidly.”
In 2005, three environmental groups raised concerns that the emergency spillway at California’s Oroville Dam wasn’t properly built and posed serious risks.
The groups — Friends of the River, Sierra Club and the South Yuba River Citizen’s League — described their worries in a motion to the Federal Energy Regulatory Commission, which was considering the dam’s relicensing.
The environmentalists wanted federal officials to require modifications including building a concrete- armored spillway rather than leaving it a concrete “lip” above an unprotected hillside prone to erosion. They warned that given the spillway’s design, uncontrolled floodwaters “could not only cause additional damage to project lands and facilities but also cause damage and threaten lives in the protected floodplain downstream.”
State officials who manage the dam dismissed those concerns at the time, and federal regulators are still considering the license renewal.
It remained unclear when residents might be allowed to return home. Croyle says his agency may need 15 days or longer to put a plan in place to make repairs.
“The danger could persist for a day or two or even longer,” says Kelly Houston, deputy director of the California Governor’s Office of Emergency Services State Operations Center. “People should not have an expectation they would come back ( home) in a short number of hours. ... We don’t know what Mother Nature is going to do.”
It wasn’t clear how many people had defied the order or been unable to leave.
Lucy Watt, 65, of Oroville decided to spend Sunday night in her car on top of the dam, figuring it was the safest place to be.
“Everybody’s scared,” she said Monday, but she was more cold than scared; temperatures were in the upper 40s overnight.
Those who defied the evacuation order and came home early returned to ghost towns — closed shops and empty parking lots and nervous calm in neighborhoods.
“My faith supersedes everything else, and I just feel like I’ll be safe,” says James Campbell, 47, of Oroville. “We will be fine.”
Janet Frye, 48, found her Yuba City, Calif., home, 2 miles from the Feather River, just as she had left it. Special photo albums were placed on the highest shelves. She returned to check on friends and planned to stay with other friends in Colusa County.
George Ayers, who’s 82 and uses a wheelchair, says he’ll stay put in Oroville.
“I’m crippled up real bad. But you know, it’s silly,” Ayers says of the evacuation order.
“I’ve been in this town over 50 years, and I don’t let too much scare me.”