When I started looking into the dam failures called out in the post, Our Aging Infrastructure, I never dreamed I would find so much information of bureaucratic ineptitude putting people at serious risk, because reasons. Mostly the reasons are around “We don’t want to ask those people for more money,” or “We don’t want to spend money on what the engineers say we should spend money on.” Case in point, the Oroville Dam spillway (near) disaster of February 2017.
Why is all this important? Forget about building new infrastructure, we are not even maintaining the infrastructure we inherited. Members of previous generations now seem like giants — When did we become so small?
When the Oroville Dam spillway failed in early 2017, I didn’t hear too much about it, or I didn’t pay too much attention. The media was mostly in a frenzy about the 2016 election, and the early part of the “Russia, Russia, Russia!” insanity. But it was a bigger deal than I knew at the time. Like the Space Shuttle disasters, it was an engineering problem, compounded by management’s unwillingness to listen to reason. It was also a failure in multiple modes‡, and the root causes of the failures were known to management. They just didn’t want to believe the engineers.
Bob Bea was a professor of engineering at Cal Berkley. Before he retired he was part of the Center for Catastrophic Risk Management. As outside experts, not hired by or associated with California’s Department of Water Resources (DWR) or The Division of Safety of Dams (DSOD), he and Tony Johnson examined all of the publicly available documents on the incident in Oroville from February of 2017.
A Review: On 7 February 2017 a portion of the main spillway at Oroville Dam failed. Specifically station 3300 failed. The spillway gates were closed. This being in the middle of the wettest winter on record for northern California, the lake levels rose to 900 ft above sea-level, and then the water began to pour over the emergency spillway. It was the first time that had ever happened. Within 24 hours erosion of the emergency spillway threatened to undermine the 30 foot weir, threatening folks living downstream. 180,000 people were ordered to evacuate, and the main spillway was reopened. The resulting destruction of the main spillway and erosion of the surrounding land dumped 1.7 million cubic yards (or so) of debris into the tailrace of the hydroelectric plant at Oroville Dam, The Hyatt Power Station, threatening to flood and destroy the power station.
There is way too much information on the initial emergency to include here. There are hours of video from DWR, and more from Blancliro. Even the link at the top, barely scratches the surface of the report. The main report, can be found at the following link. Root Causes Analyses of the Oroville Dam: Gated Spillway Failures and Other Developments.
That report details several problems going back to the construction of the dam in the 1960s.
- There were problems with the design of the spillway, at least by modern standards. It lacked the ability to prevent water intrusion and lateral movement.
- The spillway was only 4 to 6 inches thick in some portions.
- The spillway design called for removal of soil and “incompetent rock” and building only on solid rock or concrete. This was not done and the spillway was (in part) built on graded fill.
- The spillway was not anchored to the ground effectively.
- Maintenance was lacking in several areas. Patches to the spillway were poor. Trees were allowed to grow close to the spillway, where roots could contribute to undermining it.
There is another report, referenced in the Bea and Johnson report, The “Watering Down” of the Department of Water Resources Division of Safety of Dams. That report calls out…
- Lack of Industry-standard maintenance.
- Pressure to hold down maintenance costs.
- lack of concern in addressing
- concrete spalling
- concrete cracking
- Missing welds
- cracked cables in the spillway-gate trunion mechanism
Both reports note that the dam may be in danger of catastrophic failure. Back to the first report from Bea and Johnson.
Oroville Dam may be facing a breach danger from a serious and a dangerous form of a slow motion failure mode of the left abutment of the dam.
There is evidence of seepage through the dam. It is an earth abutment dam, and could be experiencing uneven or “Differential Settlement.” DWR can’t really tell you, however because none of the sensors that could give warning are functional.
Why does the tallest earthen dam in the U.S.A. have zero working Piezometers to detect any threat to a potential internal instability to warn citizens of a pending breach?
In a word: bureaucracy. (“Those dam engineers always want to spend money on something.” Or are they damn engineers?)
The federal agency responsible for hydroelectric dams has been asking for YEARS to have this sensor issue fixed, but DWR doesn’t want to spend the money. Or something. You could not pay me to live downstream of Oroville Dam, right now. Maybe it is fine. But I don’t want to bet my life on a “maybe.”
And that “systemic problem” Professor Bea mentions that forms the title to this post?
Since word of our work has gotten out, we’ve had engineers and water managers contacting us from all around the country, and the basic message is ‘Holy Crap! We’re having the same problems with our dams.’ Oroville is just the most obvious signal of a national, systemic problem.
We are not maintaining our aging infrastructure, and that is literally catastrophic.
‡ When people plan for disasters, or even think about potential problems, they look at things in this way: “A could fail, or B could fail.” They almost never look at what would happen if “A fails then B fails.” In the case of Oroville, there were indications that neither the main, gated spillway nor the emergency spillway were up to current engineering standards. Either could have been addressed at anytime during the 5-year-drought that preceded 2017, but as Dr. McCoy (of Star Trek) pointed out, “The bureaucratic mentality is the only constant in the universe.”)
Coda: I thought I would include good, non-sensational video recapping the events at Oroville (that is less than 30 minutes long). This one by California’s Department of Water Resources is a good overview, and only 5 minutes (or so) long. More video is linked below the embedded one, in case anyone is interested.
From April 2017, a video timeline of the events that lead to the destruction of the spillway, and the near-disaster at the emergency spillway. A Timeline of Oroville Events – 2017. It contains some great drone footage of the initial aftermath.
A month after the spillway failure: this video gives a view of the scale of the clean-up of the debris dumped in the Thermolito Diversion Pool. This debris from the collapse of the spillway, and the subsequent erosion had to be removed to save the Hyatt Power Plant. Oroville Spillway March 6, 2017. And a companion video that shows the 24/7 nature of this work. Oroville Spillway March 4 and 5, 2017. That 2nd video has a great bit of timelapse at about 1 minute, 40 seconds in, which is only a few seconds long, which is kind of amazing.
Like I said, there are hours of video, if you’re interested.