Tens of thousands of Northern California residents were forced to evacuate on urgent basis after a spillway appeared to be in danger of imminent collapse.
They remain in shelters as engineers worked to shore up a crumbling overflow channel and drain the rain-swollen reservoir at the United States' tallest dam before new storms sweep the region.
“We're doing everything we can to get this dam in shape that they can return and they can live safely without fear. It’s very difficult," California Gov. Jerry Brown told reporters during a news conference.
Brown also sent a letter to President Donald Trump requesting an emergency declaration that would open up federal assistance for the affected communities.
However, officials were apparently warned several times that the Oroville Dam emergency spillway wasn’t safe , yet they didn’t listen.
In 2005, state and federal officials ignored the warnings of no less than three environmental groups who believed there was a problem with Oroville Dam’s emergency spillway.
The groups alerted the authorities that the emergency spillway, which was meant to be used in urgent situations, was not really a spillway.
In fact, it was a concrete barrier that was supposed to empty onto a dirt hillside in the event of severe flooding. However, that also meant that the water would erode the hillside and flood nearby areas.
“When the dam is overfull, water goes over that weir and down the hillside, taking much of the hillside with it,” Ronald Stork, senior policy advocate for Friends of the River, one of the groups that filed the motion told The Washington Post. “That causes huge amounts of havoc. There’s roads, there’s transmission lines, power lines that are potentially in the way of that water going down that auxiliary spillway.”
This is what exactly happened when a hole on the emergency spillway , created a crater-like hole threatening to flood the surrounding areas.
Sheets of water began spilling over the emergency spillway and onto the hillside, carrying mud and debris into the nearby Feather River.
The main spillway, a separate channel, was also damaged because part of its concrete lining fell apart last week. Both spillways are to the side of the dam itself, which has not been compromised, engineers said.
“They told us not to worry. All was good. Everything was fine. It’s all safe,” Stork said. “First of all, they’re not supposed to fail. That’s not what we do in a first-world country. We don’t do that. We certainly don’t do that with the nation’s tallest dam. An auxiliary spillway isn’t supposed to cause lots of havoc when it’s being used.”
Asked about the 2005 warning, Bill Croyle, acting director of the Department of Water Resources, said he’s not familiar with the conversations that happened then.
“It’s the first time it’s ever taken water,” he said of the emergency spillway. “We don’t know exactly why this erosion occurred.”
Banner/Thumbnail Credit: Reuters