Oroville Dam woes remain
With snow melting and rain forecast, experts say the real test for the Oroville Dam spillway is still to come.
The stress of evacuation and an uncertain future were enough for Donald Azevedo and his family to opt to stay a few more nights in an emergency shelter rather than risk having to do it all again.
The family was among the nearly 200 000 Californians who live downstream from the country's tallest dam who were told they could return home but warned they may have to flee again if repairs made to the battered Oroville Dam spillways don't hold.
The fixes could be put to their first test later this week with the first of a series of small storms forecast for the region expected to reach the area by late yesterday evening.
“There is the prospect that we could issue another evacuation order if the situation changes and the risk increases,” Butte County Sheriff Kory Honea said Tuesday, telling residents they could return home but to remain vigilant.
“My plan is to stay here,” said Azevedo, who evacuated from Marysville with his wife, Tasha, their four Chihuahuas and more than 30 relatives. They spent two nights at the Nevada County Fairgrounds in Grass Valley, California and he planned to wait out this week's upcoming storm before returning home. Many at the shelter said a drive that should have taken one hour took six hours on Sunday.
“I'm not trying to risk traffic, being stuck in floods. I'm safe where I'm at,” Azevedo said.
Residents living below the Oroville Dam were suddenly ordered to evacuate Sunday afternoon after authorities had assured them for nearly a week that the dam was sound despite a gaping and growing hole found in the structure's main spillway. The order came after authorities feared an earthen emergency spillway used when the lake behind the dam overflows its capacity appeared ready to fail Sunday because of erosion.
Two days after issuing the evacuation order, officials lifted it Tuesday but uncertainty remained.
Over the weekend, the swollen lake spilled down the 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.
State and federal officials ignored calls in 2005 from environmental groups to armour the earthen spillway in concrete to prevent erosion. Federal regulators concluded the earthen spillway could handle a large amount of overflow after water agencies that would have had to pay for the upgrade argued it was unnecessary.
Others fear the real test is still to come in the weeks ahead when a record amount of snowfall melts in nearby mountains.
Dozens of construction crews were working around the clock dropping 1 200 tons of material on the earthen emergency spillway per hour using heavy equipment and helicopters and the area is being continually monitored with the help of drones carrying cameras, the state water agency said.
Preliminary estimates say permanently fixing the hole in the main spillway could cost US$100 million to US$200 million, Croyle said. Experts are drawing up plans for repairs that will begin after the spring runoff season ends.
NAMPA/AP
The family was among the nearly 200 000 Californians who live downstream from the country's tallest dam who were told they could return home but warned they may have to flee again if repairs made to the battered Oroville Dam spillways don't hold.
The fixes could be put to their first test later this week with the first of a series of small storms forecast for the region expected to reach the area by late yesterday evening.
“There is the prospect that we could issue another evacuation order if the situation changes and the risk increases,” Butte County Sheriff Kory Honea said Tuesday, telling residents they could return home but to remain vigilant.
“My plan is to stay here,” said Azevedo, who evacuated from Marysville with his wife, Tasha, their four Chihuahuas and more than 30 relatives. They spent two nights at the Nevada County Fairgrounds in Grass Valley, California and he planned to wait out this week's upcoming storm before returning home. Many at the shelter said a drive that should have taken one hour took six hours on Sunday.
“I'm not trying to risk traffic, being stuck in floods. I'm safe where I'm at,” Azevedo said.
Residents living below the Oroville Dam were suddenly ordered to evacuate Sunday afternoon after authorities had assured them for nearly a week that the dam was sound despite a gaping and growing hole found in the structure's main spillway. The order came after authorities feared an earthen emergency spillway used when the lake behind the dam overflows its capacity appeared ready to fail Sunday because of erosion.
Two days after issuing the evacuation order, officials lifted it Tuesday but uncertainty remained.
Over the weekend, the swollen lake spilled down the 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.
State and federal officials ignored calls in 2005 from environmental groups to armour the earthen spillway in concrete to prevent erosion. Federal regulators concluded the earthen spillway could handle a large amount of overflow after water agencies that would have had to pay for the upgrade argued it was unnecessary.
Others fear the real test is still to come in the weeks ahead when a record amount of snowfall melts in nearby mountains.
Dozens of construction crews were working around the clock dropping 1 200 tons of material on the earthen emergency spillway per hour using heavy equipment and helicopters and the area is being continually monitored with the help of drones carrying cameras, the state water agency said.
Preliminary estimates say permanently fixing the hole in the main spillway could cost US$100 million to US$200 million, Croyle said. Experts are drawing up plans for repairs that will begin after the spring runoff season ends.
NAMPA/AP
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