Dammed If We Do: What Could Happen If Oroville Dam Fails

By Glen Martin

The news from Oroville Dam on Tuesday is nominally better. Water isn’t flowing over the top of wall at the auxiliary spillway, and erosion has stopped. Water releases are ahead of inflows, and the reservoir’s level is falling. Perhaps most encouraging for the close to 200,000 displaced locals downstream of the dam, the evacuation alert has been downgraded.

But the situation on the Feather River is by no means stable. According to UC Berkeley’s Robert Bea, professor emeritus of civil engineering and co-founder of UC Berkeley’s Center for Catastrophic Risk Management, the state may be teetering on the cusp of utter disaster, one major storm away from an infrastructure failure that could send a wall of water down the Sacramento Valley, wiping out small towns and farmland, inundating parts* of the city of Sacramento, and flooding the Sacramento-San Joaquin Delta, flattening its levees and knocking out the gigantic state and federal pumps that supply much of Southern California with water.

Bea is one of the world’s top authorities on disasters of this scale, a lead investigator in many of the nation’s worst disasters over the past couple of decades, from the destruction of the space shuttles Challenger and Columbia to Hurricane Katrina to the Deepwater Horizon explosion. He has compiled a meticulously detailed database on more than 600 engineering failures (many of them stunningly catastrophic), and helped develop an interactive system that allows managers to assess and respond to risk in real time.  

And Oroville, says Bea, is potentially another Katrina. Or worse. Moreover, the response to date hasn’t really been effective, not because the responders are incompetent, but because options are limited.

“You have a full breach on the primary spillway, and a large hole in the auxiliary spillway that’s eating toward the wingwall,” Bea says. “Good people are doing what they can, but it’s hardly an adequate remedy. They’re dropping big bags of rocks in the holes, but it’s like the little Dutch boy sticking his finger in the dike.”

Though the California Department of Water Resources (DWR), which did not return calls for comment, is now releasing more water than is coming into the reservoir and the level is falling, that could all change with the next round of storms. 

“They may not have a choice but to put more water [down the auxiliary spillway], and if that happens the erosion will resume and they could lose the whole shebang,” Bea says.

Oroville Dam, he says, has systemic flaws that make it inherently unsafe, flaws that are now increasingly manifest as the structure is subjected to cascading stresses.  The dam’s problems are not new to either Bea or his counterparts at DWR.

“There were persistent signs of the problem as far back as 2008, and when I saw inspection reports in 2015, I got a strong sense of déjà vu. I saw forces in play that were similar to what we saw with Katrina.”

Disasters like Katrina and Oroville, says Bea, are engendered in large part by the prevailing culture in American engineering. Unlike European engineers, he says, American engineers think in terms of inevitable success, not possible failure.

“They don’t design adequately for what can go wrong,” he says. “That’s how you end up with an auxiliary spillway that isn’t even armored, that’s just easily eroded earth and rocks. That’s a unique American approach to engineering. If they had the same attitude in the Netherlands, for example, they’d all be swimming by now. Europe can’t afford system failures.”

“In many cases, you have public servants sitting on deteriorating systems, and they don’t even recognize the dangers.”

Furthermore, American engineers tend to focus on the “components” that constitute their specialties, says Bea. But when they put all their components together in a megaproject, not enough attention is paid to the stresses the system as a whole may endure under a wide variety of conditions. Steel beams and concrete compounds may test out admirably in the lab, but when they’re conjoined in a dam or bridge or building exposed to weather for years and years, things may not turn out like the numbers originally indicated.

“System geriatrics aren’t well understood here,” says Bea, “and that leads to trouble, as we see time and again. In many cases, you have public servants sitting on deteriorating systems, and they don’t even recognize the dangers.”

Finally, neither politicians nor engineers get particularly excited about maintaining existing infrastructure, he claims.

“They want to build new, shiny things, like a self-supported suspension span from San Francisco to the East Bay,” Bea says. “They aren’t enthused about fixing old stuff. Nobody gets promoted for filling potholes. I call what we’re seeing at Oroville ‘The Revenge of Deferred Maintenance.’”

 As noted, Oroville’s failure would generate catastrophic downstream effects all the way to the Delta, which has major problems of its own, says Bea.

“I had several student-faculty teams looking at Delta sustainability,” he says. “We examined the entire infrastructure: levees, roads, farmlands, pumps. The conclusion was that it’s basically time to get out of Dodge, and not just because of Oroville. You could have catastrophic and terminal flooding from the San Joaquin River, for example, or a failure of Folsom Dam on the American, which is also pretty much a patch job. Or you could have a major earthquake. It just isn’t a sustainable system.”

For now, Oroville Dam and much of California hang in a parlous balance, and a potential tipping point is approaching: A series of storms are poised to hit California in the next week, with expectations of four to six inches of rain falling on Feather River watersheds.

*This story has been amended from its original version, which stated that “much of the city of Sacramento” would be inundated in the event of spillway failure at Oroville. While flooding in some parts of Sacramento seems likely officials are assuring residents that the Yolo Bypass system will protect the city.

Filed under: Science + Health
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I’mthamks for sharing the article and Prof. Bea’s opinion
My family is in Oroville the authorities waited too long got the evacuation and they went back to butte county only to find themselves two hours from bring evacuated. Is people safe anywhere in california?
Your sweeping generalization and criticism of “american engineers” is despicable. Sincerely, Matthew Clarke PE, LS
I believe you are 100% right. I live maybe 30 miles away safe in the hills from Oroville. In addition I did not noticed any rebar in their main spill way.
Rebar in the concrete would not have prevented the soil from eroding underneath the spillway. Don’t comment on issues you are ignorant of.
Well sir you can call me all of sorts of names. I will gave you this little hint my Grandmother’s maiden name was Perini.
Perini is a builder. Believe it or not contractors are NOT engineers. They complain and file lawsuits when they don’t make money and blame engineers for their problems; like this article does. Your partner Tudor is famous for this.
C’mon Matthew, you complain about sweeping generalizations about engineers and then make your own sweeping generalization about contractors. People are free to comment. As for the article blaming engineers, it simply quotes Professor Bea, who is himself a civil engineer and an authority on these types of crises. You’re free to take issue with his assessment, of course, but let’s keep it civil. No pun intended.
Wild guess here Matthew, but I don’t think Mary was suggesting that if there were rebar reinforcement in the spillway, it would have had anything to do with erosion prevention, but rather could have prevented a tensile failure over the eroded area. ;) Mary simply made an observation. As a PE, perhaps you could use this moment to educate Mary and the other ‘ignorant’ readers, on what role some added reinforcement could or could not have played in the recent events, rather than being a smug prick. But hey, you’re the PE here, don’t let a little common sense, manners and decency get in your way.
Making a hasty generalization in a comment is different than making one as the basis of an entire article published on the internet. Further the “smug prick” is the author of the article claiming that “american engineers” are to blame for the damns failure and are somehow inferior to non-american engineers. The laws of physics work the same here as they do in any other continent. No. My role here isn’t to educate the general public on reinforced concrete design. Nor is it to pass judgement on who is to blame. There is nothing wrong with being ignorant until you fail to recognize it and begin falsely blaming others.
His license to practice in California was cancelled. He isn’t an engineer in CA.
ok so now back to the problem since everyone wants to go off topic as usual
Matthew, Robert Bea has been retired since 2012. He was the recipient of the Ralph Peck Medal (2002) and the Croes Medal (1978), both from the American Society of Civil Engineers, and a member of the National Academy of Engineering since 1989. Not sure what point you wanted to make, but he is very much an engineer. I agree with Krystal. Back to the problem.
Based on the Cal Fire inundation maps, in the event of a complete dam failure the water would not reach Sacramento. I’d like to know what data the author is using to make that prediction because I have never heard that even suggested. The situation is bad enough without spreading hysteria in Sacramento if it unfounded.
I believe the man was referring to the very limited amount of rebar in the main spillway which may have helped to keep it from eroding exposing the soil underneath.
You raise a good point Beth. I’m no expert, so take this with a grain of salt. While the water will certainly reach Sacramento via the river, the question is how much if any of the city could see flooding. Officials seem to think the weirs and levees of the Yolo Bypass system will protect the city should the spillway fail, but with all the rivers running high in addition to the Feather (the Yuba, American and Sacramento), … it seems like parts of Sacramento, in particular Natomas Basin would be hard hit by a pulse of that magnitude. Hopefully nothing so catastrophic will come to pass.
Fantastic article. The water system in California was built for quick results, and the government is often guilty of giving contracting jobs to the lowest bidder. All earthen dams are not made for longevity, they are made for expediency, and it is hoped that the safeguards in place will keep the earth from eroding away. After reading “Cadillac Desert” in the late 80s, and keeping an eye on the water issues in California which are only getting worse, I moved away in 2002. Cali’s entire water system is built on a house of cards, and water waste is rampant in the agricultural sector. It is said that future wars will be over clean water, not oil or other commodities. Cali’s Achilles Heel has ALWAYS been water. It was never meant to support the millions of people or the millions of acres of crops like water thirsty rice. It is my home state and I love it, but the hubris of man over mother nature will be its downfall.
Lawyers are just as much to blame, they talked the water contractors out of reinforcing the spillway, the thought pattern was, IF the level raises at ALL to go over the emergency spillway, there is no need to put your money into it, so they gambled all this time.
thank you i live six miles down from the dam and my fear is the residents of this town who live, work and raise our children here have no say in our options to reinforce or repair our already existing dam i’ve lived here all 33 years of my life and dont want to see the beautiful scenery oroville has destroyed because officials can only see quick fixes and not long term repairs
Matthew Clarke you are right physics are the same across the world. Which is why American engineers are to blame for the spillway disaster. If you look at the awesome dirt moving power of water, common sense would tell you that if you have water cascading over a 1,700 foot long 20 foot tall concrete wall onto dirt and rock below that the dirt and rock will wash down with it. You don’t have to be an engineer to see that. Obviously the engineers knew this as they put a 3,000 ft long chute leading away from the main spill way. But as the article states “American engineers tend to think in terms of inevitable success not possible failure” which is evident with the lack of erosion protection for the emergency spillway, and lack of testing of the emergency spill way for that matter. The never planned for the main spillway to fail and never expected to need the emergency spillway. So professor Bae’s generalization on this matter is accurate. I’m sorry that offends you. You can either continue to troll articles like this one looking for people to take your frustrations out on or you can go out and try to make a difference in how your chosen field works.
No. Your argument is flawed. Just because one small group of engineers that worked on this particular project may have made some mistakes, you cannot conclude that it is some systemic problem with ALL “american engineers.” This is a ridiculous statement and the author poorly backs up. With any large body of work (such as the entire US infrastructure) you can always cherry pick the problems and use them to make obtuse criticisms. If you are going to make a generalization about “american engineers,” you need to look at the entire body of work. Problem structures that have already aged passed their intended life span or that have been improperly maintained does reflect poorly on the original design engineer.
“does [not] reflect poorly on the original design engineer”
I’d like to know just how much water would be spilled out into surrounding towns like live oak and Gridley I heard 100’ is that really possible?
I was wondering how they say that Gridley and oroville would be under 100’ ft of water?
There is no need for rudeness, Mr. Clarke. You can be the best expert in the field but if your are rude & intolerant of other less informed people, you one will hear your voice. Please be kind.
How deep would the flood water be in Gridley if the spillway fails ?
Amen Sister Back to the topic at hand…. Matt may think differently if he lived below this poorly maintained water storage structure as I do. My children will be forever traumatized after recent evac…. My biggest concern is that DWR consistently puts its potential profits far before the safety of the public residing below this POS…..this emergency overflow design is obviously flawed engineering as it failed within 24 hrs of its first being used in the 48 years since its construction! Furthermore, I feel they will do little more than what they are currently doing to make this a safe design….I am sorry but a few boulders and a little Flash-creat does not make me feel at ease….I am truly glad I live approx 25 or so miles downstream giving me at least half-a-chance to get out of Dodge should we have a catastrophic failure at said facility. From the bottom of my heart, I thank Dr. Bea for being willing to put some truth out there re: the actual dangers of this aging and poorly maintained facility! Thank you, Sir, thank you, thank you, thank you!
I’ve been involved with FEMA map studies as a Building planner checker, and of course yes the water would & will reach Sacramento as it does now. Will levels increase above flood stages? Yes of course if the dam fails that’s what happens now when increased real eases from other dams. The question is how much & how high. Today Shasta Dam releases on top of Oroville Dam releases adding to the up coming raining event which can compound the flooding would be the issue. If the dam fails then there will be flooding all downstream of the rivers. That’s a given. And Matthew, I’ve discussed projects with engineers over 20 years, your defensive attitude is very typical. Is the dam near failure? Yes, until it was not an adequate design . True?
I agree, I’m so tired of Americans being disparaged time and time again! NO other country compares to America
Subject: No Rebar In Main Spill Way If this is true it is a major oversight. Makes you wonder if rebar was used in the dam. I built my patio and driveway using rebar!
Hi Beth, I’ve been looking at that map too— I don’t think it implies that the water wouldn’t reach Sacramento, though. The water has to reach Sacramento - there’s nowhere else for it to go. The map simply shows where the water would spread within a given time frame (something like 6 or 7 hours?). By then it would have begun to surround both sides of the Sutter Buttes. According to a recent Sacramento Bee article, the mayor of Sacramento said that the state water board had informed him that in a worst-case scenario of catastrophic failure, the waters would take 12 hours to reach Sacramento. They assured him that the weirs and bypasses built into the Sacramento River would be able to divert the water from flooding Sac. I take that with a large grain of salt. The whole delta system of earthen levees is already in terrible repair and in any case was built to manage seasonal river-flooding from rain and snow-melt, not catastrophic dam failure. Sacramento really is built into a flood plain, and people should consider that and plan for possible consequences.
Here’s a link to a page showing an official inundation map of the area that would be impacted within the first 6 hours in the event of a catastrophic dam failure (which could happen without the actual dam structure failing, if the hillsides beside the dam failed). This would not be a simple river-overflowing-its-banks type of scenario, it would be a violent and sweeping flood - Oroville lake is a LOT of water: https://twitter.com/Opschief7102 I think officials and news media have downplayed the actual consequences of this threat, maybe because of not wanting to incite hysteria. Maybe that strategy will work out fine if these desperate patching-up attempts hold back the water until the spring thaw is over and real repairs can be made this summer. But if the patches don’t hold, that downplaying will in retrospect look like criminal negligence.
This Oroville Dam situation reminds me of the St. Francis Dam failure in Southern California in 1928. It had been designed by William Mulholland who was also responsible for construction of the aqueduct from the Owens Valley to LA. I have been told that he was self-taught and this disaster was responsible for the establishment of PE licensing in California.
they need to cut a , ” Separate pathway /../ for the hidro spillway , cut through the hillside.. that cant passably be filled by debree from the main spillway or the emergency, when they have to start using them again.. , and DAM it…!! leave all the concrete alone , ” IT”S HOLDING BACK A MUD SLIDE..”,. that will/ could allow the HOLE DAM to FAIL…!! everyone in the path Should get the HELL out of the way…!! input is 10 time the output without rain..,with rain on the way,.. then the SNOW MELT,..,?? it’s not when it will ” over top and erode and fail”…. it’s when.!! this is going to FAIL ,.and if you weight to here a evacuation order to get out …? the Roads will be to JAMMED up to DO ANYTHING.., ..?? get THE HELL OUT OF THE WAY….. NOW….!!!!!