What Really Happened at the Oroville Dam Spillway?
May 18, 2021 12:20 PM   Subscribe

 
Fascinating, thank you!
posted by kokogiak at 1:06 PM on May 18, 2021 [1 favorite]


Indeed.
posted by Splunge at 1:24 PM on May 18, 2021


That was really interesting and so well presented.
posted by latkes at 1:33 PM on May 18, 2021 [1 favorite]


IMO this doesn't really answer what happened, not exactly.

What happened was the engineering faults and repairs that dam regulators and engineers pointed out beforehand that needed to be done, but the cost was like $100m, so everyone said "nah", moved on, and hoped for the best.

Instead it goes excellent laymans' explanations for them and the damage they did while the failure was occurring (and why regulators recommended the repairs in the first place), which is equally cool and valuable, but not exactly the same thing.
posted by The_Vegetables at 1:43 PM on May 18, 2021 [7 favorites]


well that was entirely fascinating!
posted by supermedusa at 1:45 PM on May 18, 2021


The PDF is fun reading if you like to see dozens of pages of "all y'all done fucked up."
posted by seanmpuckett at 1:56 PM on May 18, 2021 [3 favorites]


The pictures and video are stunning, and Grady is great. He seems to deliberately avoid policy questions to focus on the engineering and science, which seems like a fine choice to me -- and one that's reinforced by some of the inane commentary.
posted by Slothrup at 2:01 PM on May 18, 2021 [1 favorite]


latkes wrote...
That was really interesting and so well presented.

Grady is a treasure.
posted by Tell Me No Lies at 2:03 PM on May 18, 2021 [5 favorites]


Grady is a treasure.
tigrrrlily and I have thought this for quite a while :)
posted by Flight Hardware, do not touch at 2:19 PM on May 18, 2021 [1 favorite]


I live nowhere near the dam. But I remember watching in horrified fascination as this all played out, including several mentions of the negligence The_Vegetables mentioned. That was a good explanation of what happened, but I find myself wishing for his "what happened after that" video. I did find this article that says something about the repairs and upgraded replacement spillways...made by the people who did it, so of course it's pretty glossy and rah-rah.
posted by Greg_Ace at 3:06 PM on May 18, 2021 [2 favorites]


This dam is so much larger than I pictured. I live in Northern CA, and somehow pictured it as another rinky-dink local construction.
posted by migurski at 3:21 PM on May 18, 2021


My mother was living in Chico during that time. When something like 180,000 people are evacuated from the Oroville area to Chico, that was like a dam bursting people into town. There were no facilities to handle that many now homeless people. It was like the population was more than doubled. So the dam and it’s maintenance and repairs were badly handled. The required evacuation was also handled in a similar way.
posted by njohnson23 at 4:13 PM on May 18, 2021 [1 favorite]


The PDF is fun reading if you like to see dozens of pages of "all y'all done fucked up."

As someone who spent way too much time reading NNPP incident reports in the military and since getting out has spent way too much time reading NTSB maritime accident reports, this is literally one of my favorite things.
posted by Mr.Encyclopedia at 4:43 PM on May 18, 2021 [5 favorites]


From the PDF:

The slab cracking and underdrain flows, although originally thought of as unusual, were quickly deemed to be “normal,” and as simply requiring on-going repairs. However, repeated repairs were ineffective and possibly detrimental.

This near disaster turns out to be yet another instance of the age old practice of normalization of deviance.
posted by monotreme at 5:21 PM on May 18, 2021 [11 favorites]


Is it too early to start taking bets on how long the "improved" spillways will last?
posted by Greg_Ace at 5:45 PM on May 18, 2021 [1 favorite]


If you want a lighthearted take on what happened before the spillway gave way, The Onion has you covered.
posted by tigrrrlily at 6:56 PM on May 18, 2021 [2 favorites]


Club Grady for sure. Civil Engineering (mostly) is pretty cool.
posted by zengargoyle at 7:06 PM on May 18, 2021


To answer the question in the title: irresponsible mismanagement from DWR, begotten of hubris. Appendix L of the report addresses how fifty years' lack of accountability culminated in two million yards of earth being washed into the Feather River. The video addresses the physical process thereof with admirable clarity.

After Lake Oroville rose from 789' to 849' in five days in January, DWR held it there for more than three weeks. For much of that time, they were discharging only as much water as their power plant could handle. Until another set of storms threatened to raise the lake another sixty feet, when they belatedly opened the headgates, only to find the required flows combined with substandard engineering and maintenance caused the spillway to collapse. Coincidentally, at the location of damage photographed weeks before (p. I-17/18).

DWR then decided to "save the plant before anything else" (p. L-8) and reduced flows over the service spillway to allow the lake to overtop the emergency spillway. Thousands of tons of water per second then scoured the vegetated hillside beneath the concrete weir, threatening to undercut it. The state finally brought the county into the decision-making process when they thought the headward erosion might reach the weir within the hour. This could have swept away sections of Yuba City and Marysville and indundated towns fifty miles downstream.

YubaNet's live updates address the urgent evacuation. While 35,000 residents of southern Butte County were instructed to go north toward Chico, another 153,000 people from Yuba City and Yuba County were instructed to go a different direction. Neither the evacuees nor the destinations had time to prepare. That's not on the local jurisdictions' emergency management; that's on DWR cowboys prioritizing DWR assets above all else (p. L-19). And to some extent on the State Water Contractors and FERC for rejecting demands to armor the emergency spillway, but DWR should never have let it get that far.

This was not a near-disaster; it was a ten-figure disaster that could have been much worse or could have been avoided with preventive maintenance.

The engineer clarifies the engineering aspects while the Independent Forensics Team shares insights into the entire debacle.
posted by backwoods at 12:23 AM on May 19, 2021 [7 favorites]


It's nice to get a measured Grady retrospective on Oroville. At the time I was a total groupie for Juan Browne and his Blancolirio channel - all his Oroville vids of the unfolding disaster without the benefit of hindsight.
posted by BobTheScientist at 12:29 AM on May 19, 2021


I randomly watched this the other day... super interesting. That channel is consistently good, fwiw...
posted by ph00dz at 10:14 AM on May 20, 2021


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