You may have heard of the Oroville Dam and the fact that residents below the dam are being evacuated in case the emergency spillway fails:
The threat of imminent collapse of the Oroville Dam emergency spillway continued to ease Monday morning, hours after authorities ordered the evacuation of more than 180,000 downstream residents upon discovering damage to the structure.
But there is still serious concern about the condition of the auxiliary spillway, and it’s unclear when residents will be able to return to their homes.
With a storm expected to arrive Wednesday, the state Department of Water Resources needs to make room for the water that will be flowing in. The agency aims to drain about 1.2 million acre feet of water from the reservoir over the next day or so. The capacity of the reservoir, California’s second-largest, is about 35 million feet.
Gov. Jerry Brown declared an emergency late Sunday to beef up the state’s response to the evacuations and dam threat…
…Water expert Peter Gleick, of the Pacific Institute, said failure of the emergency spillway would allow an uncontrolled release of water to surge down the Feather River. Such a breach could then undermine the earthen hill beneath the spillway, causing a catastrophic release from the reservoir.
He cautioned Sunday night the catastrophic scenario did not appear likely, but engineers will know more when they inspect the damage to the emergency spillway in coming days.
“People don’t realize how powerful water can be,” Gleick said. “We use water to cut steel in some industrial operations. Uncontrolled water is a dangerous thing.”
So there’s the prospect of a wall of water rolling down a valley and destroying everything in its path if this spillway fails. Got it.
If you want to know how the failure of an emergency spillway can be so scary, VOX have done a fantastic job of explaining the details of the situation here:
…for the first time in the dam’s 50-year history, water began pouring over the top of the auxiliary or “emergency” spillway to the left of the main concrete chute — a feature that serves as a last resort.
As you can see in the video below, water began coursing down the wooded hillside, washing debris into the Feather River below.
Except this created a new — and even more worrisome — dilemma: The water began eating away at the ground beneath the top of the auxiliary spillway, carving deep gullies into the earth. On Sunday afternoon, the Department of Water Resources warned that the lip of the auxiliary spillway, which was never built to be as sturdy as the main spillway, was in danger of “failure” if the ground beneath gave way.
That was terrifying: If the 30-foot-high concrete barrier at the top of the auxiliary spillway collapsed, billions of gallons of water would start bursting from the reservoir all at once, swamping the Feather River below. Joe Countryman, a member of the Central Valley Flood Protection Board, explained the potentially dire consequences to the Sacramento Bee: The river would crest far higher than the levees downstream are equipped to handle. Dozens of towns between Oroville and Sacramento would flood. Highway 70 would be inundated. It’d be one of the worst environmental disasters northern California had ever seen.
So officials warned the 188,000 people in the floodplains to get out — and fast.
And things are about to get serious, because they have some heavy rain coming their way:
The long-term forecast has rainfall totals within the watershed that are showing the exact spot where Lake Oroville watershed is located will get 11.62 inches of rain over the next 10 days, the most accumulated rainfall in the entire western USA. [emphasis original]
And that’s a big problem… see the dam is already full, actually at 151% of capacity (many dams are built with airspace to help buffer against floods, so their ‘100% capacity’ is actually a nominal figure, not the point at which it’s full. In the case of Oroville, 151% is most definitely full!) which means that any water flowing into it must be immediately released again, or else the dam might overflow, which could cause the dam itself to fail.
But this is just an unfortunate coincidence right? It’s just bad luck that so much rain would come at a time when the authorities suddenly discovered that the dam was damaged? Uh, no. They’ve known about the issues for decades, and members of the community tried to get this fixed 12 years ago:
More than a decade ago, federal and state officials and some of California’s largest water agencies rejected concerns that the massive earthen spillway at Oroville Dam… could erode during heavy winter rains and cause a catastrophe.
…
FERC rejected that request, however, after the state Department of Water Resources, and the water agencies that would likely have had to pay the bill for the upgrades, said they were unnecessary…
…
Federal officials at the time said that the emergency spillway was designed to handle 350,000 cubic feet per second and the concerns were overblown.
“It is important to recognize that during a rare event with the emergency spillway flowing at its design capacity, spillway operations would not affect reservoir control or endanger the dam,” wrote John Onderdonk, a senior civil engineer with FERC, in the Federal Energy Regulatory Commission’s San Francisco Office, in a July 27, 2006, memo to his managers.
“The emergency spillway meets FERC’s engineering guidelines for an emergency spillway,” he added. “The guidelines specify that during a rare flood event, it is acceptable for the emergency spillway to sustain significant damage.”.
…
This weekend, as Lake Oroville’s level rose to the top and water couldn’t be drained fast enough down the main concrete spillway because it had partially collapsed on Tuesday, millions of gallons of water began flowing over the dam’s emergency spillway for the first time in its 50-year history.
On Sunday, with flows of only 6,000 to 12,000 cubic feet per second — water only a foot or two deep and less than 5 percent of the rate that FERC said was safe — erosion at the emergency spillway became so severe that officials from the State Department of Water Resources ordered the evacuation of more than 185,000 people. The fear was that the erosion could undercut the 1,730-foot-long concrete lip along the top of the emergency spillway, allowing billions of gallons of water to pour down the hillside toward Oroville and other towns downstream.
So in other words, the ‘experts’ said that this wouldn’t happen, and then it did. The ‘experts’ said the spillway could withstand 350,000 cubic ft per second, and then it failed under 12,000 cubic ft per second.
I have to wonder, to what degree did the Global Warming religion play into this? Because after all, the ‘experts’ said it wasn’t going to rain like this again in California…
California is still in a state of drought. For now, maybe forever.
Even the governor thinks so. On May 9, Jerry Brown issued an executive order that makes permanent certain emergency water cuts from the past few years.
To what degree with the Californian State Government, as well as the relevant water authorities, buy into the old Tim Flannery chestnut:
Although we’re getting say a 20 per cent decrease in rainfall in some areas of Australia, that’s translating to a 60 per cent decrease in the run-off into the dams and rivers. That’s because the soil is warmer because of global warming and the plants are under more stress and therefore using more moisture. So even the rain that falls isn’t actually going to fill our dams and our river systems…
I’m speculating here, but did they really believe that the obviously cracked and damaged spillways at the Oroville Dam would work just fine under pressure, or were they really just dismissing the public concerns because they believed the emergency spillway would never be needed thanks to Climate Change?
We’ll never know of course, but the drought in California has been turned into a ‘sign and wonder’ for the true believers of Global Warming, so the idea that the drought would break with flooding rains was a sacrilegious idea. It was unthinkable, and to suggest such would indicate a lack of faith in the Global Warming dogma. In reality the west coast of the US has a lot in common with Australia’s climate… a long history of droughts and flooding rains, and just like we saw in Australia after 12 years of drought, the rains returned with a vengeance and caused record flooding.
So now over 180,000 people have been evacuated, lives are turned upside down, businesses are shuttered, and there’s a very real risk that ‘flooding rains’ in the next 10 days are going to wipe the town of Orville off the map as billions of liters of water spill down the hillside if the emergency spillway fails completely.
What’s the lesson here? I think there’s two:
- Don’t politicize engineering. We’ve seen it here in Australia with the handling of the water catchments in Victoria as well as the entire Murray Darling Basin. Engineers are (mostly) pretty damn good at what they do, and I find it hard to believe that the obviously damaged emergency spillway (along with the also damaged regular spillway) were signed off on by an engineer on basis of his engineering prowess. It makes far more sense to me that it was signed off on under political / ideological pressure.
- Spending money on things that don’t matter has a dark underbelly… there’s no money to spend on the things that do. California is a particularly ‘progressive’ state in the US, known for spending money on social programs with nigh on reckless abandon. And the state’s finances are suffering. To what degree was the decision that the Orville Dam spillway was A-OK influenced by the fact that there was no money left to fix it in any case? Again, we’ll never know. But if the engineers had been allowed to do their job without political influence, and if the state of California had money in the bank, would the citizens concerns from 10 years ago have been dismissed the same way? I doubt it.
California may be about to offer a sobering cautionary tale in the consequences of ignoring your infrastructure on the basis of ideology, or because you’ve spent all your money on social programs.
I can only hope the rest of the US, and the rest of the world, are paying attention to the lessons behind this potential disaster. Stop spending on welfare and consumption, and invest instead in your infrastructure… we can’t afford not to.
And for what it’s worth, I’ll be hoping the rains don’t fall and the spillway doesn’t fail. Some people may enjoy ‘disaster porn’ and be wishing it to fail, but count me out. Those are real people with real lives and everything to lose. And it should never have come to this.
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