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Areas near Sacramento evacuated as Oroville spillway collapse feared

156 points by akaru 10y ago

lisper 10y ago
TIL the Oroville dam is the highest in the USA, 44 feet higher than the Hoover dam. It's kinda mind boggling that it could actually fail tonight (though the latest reports indicate that the situation is improving).
- aji 10y ago
  to clarify: it's not the dam itself that's at risk of failure, but the emergency spillway. while this scenario would be catastrophic, it's far less catastrophic than the entire dam failing
  - ChuckMcM 10y ago
    Think about that statement, what does is mean to you that the "emergency spillway failed" ? The ES is the portion of the dam that is slightly lower than the overall height of the dam so that in the event the main spillway was unable to release water fast enough, the water would start spilling here rather than across the dam. If it "fails" then a portion of the dam ceases to exist. That releases water through that hole uncontrollably. At which point losing containment is generally a matter of when not if. If it fails, it will be a double disaster, many people will lose property, and California will lose some or all of the water in its largest reservoir. The challenge is going to be keeping ahead of it through to the next storm.
    - khuey 10y ago
      The emergency spillway is around 30 feet high, the dam itself is 770 feet high. The amount of water released from a failure of the emergency spillway will be enormous, but still much smaller than the amount of water released by a complete dam failure.
      - k26dr 10y ago
        To clarify, the emergency spillway is 30 ft below the top of the dam, not 30 ft high
      - ChuckMcM 10y ago
        http://www.sacbee.com/news/local/article132356269.html http://www.sacbee.com/news/local/article132356269.html provides an excellent description of the challenge. The hillside where the emergency spillway is would be at risk.
        verytrivial 10y ago
        Excellent link, thanks. I found the following comment sobering: "Countryman: It’s not going to be the (main) embankment failure, but it’s a failure. If it does happen, there’s nothing saying that the ground is going to stay where it is. That force of water will start tearing that hill apart, and it could eat back into the reservoir and drain the reservoir."
    - djcapelis 10y ago
      > California will lose some or all of the water in its largest reservoir Lake Oroville is actually the second largest reservoir and one of six reservoirs with a storage capacity over 1M acre feet of water: http://cdec.water.ca.gov/cgi-progs/reservoirs/RES http://cdec.water.ca.gov/cgi-progs/reservoirs/RES The largest is Lake Shasta: http://cdec.water.ca.gov/cgi-progs/stationInfo?station_id=SHA http://cdec.water.ca.gov/cgi-progs/stationInfo?station_id=SH... with a storage capacity of 4.3M acre feet of water, approximately 800,000 more acre feet than Lake Oroville.
    - Obi_Juan_Kenobi 10y ago
      > At which point losing containment is generally a matter of when not if. No, it's not. The local geology is fairly solid rock. The overflowing water will wear down the overlying soil and loose Earth, but should be sustained by the rock formation. It is a risk, certainly, but such a site is chosen because of the suitable foundation. The issue right now is to see how the spillway fares over the night. If it handles the increased flow, then it should be able to continue to relieve the situation. To be fair, I think it is a little ethically troubling to refer to the emergency spillway as anything other than that (e.g. auxiliary spillway), but it is designed to function in an emergency, not just fail catastrophically.
      - PuffinBlue 10y ago
        I'd love to get a source on this info. I've been looking for info on the geology of the exact area and the dam construction to assess this exact point. Where did you find the info on the area being solid rock? That would go a long way to giving an idea as to how bad any increased failure might be.
- djcapelis 10y ago
  So far, the only failure foreseen is to the auxiliary spillway which would definitely lead to an uncontrolled release of water from the lake, but is a separate structure from the main dam. There's definitely worries about the erosion on the main spillway moving back upstream towards the dam, but that is something folks are going to have to look at and consider over the remaining duration of the water season, unlikely to be a danger tonight.
  - lisper 10y ago
    No, the emergency spillway is part of the dam. Failure of the spillway could lead to failure of the entire dam. It's not likely, but it's possible. Once large quantities of water start going where they weren't designed to go, all bets are off.
    - djcapelis 10y ago
      It certainly could, but they are literally separate structures, as repeated stated by the actual engineers who maintain the dam.
      - jcranmer 10y ago
        The hillside underneath the overflow spillway is literally washing away. You can see downhill portions of the spillway where the waters ate away 10, 20 feet of vertical elevation. If that erosion backs all the way up to the reservoir itself, then the lining could fail (much as the main spillway did). At that point, it doesn't matter if the dam is still standing, if there is a gash right next to it lowering the effective maximum water level by several feet. I don't know enough about the geology of the area to know how likely it is to happen. But history does show that dams can go very quickly once erosion reaches the dam/reservoir, so alarm isn't exactly unwarranted.
        kobeya 10y ago
        It'll hit bedrock.
guard-of-terra 10y ago
https://www.youtube.com/watch?v=yhzKVdSnPmg https://www.youtube.com/watch?v=yhzKVdSnPmg Live coverage. They say situation is better now that drain is sufficient.
- PuffinBlue 10y ago
  That stream has now ended, but you can still see the live webcam feed: https://www.youtube.com/watch?v=hSaAE6MbKE0 https://www.youtube.com/watch?v=hSaAE6MbKE0 Not that you can see much as it's dark...
thatswrong0 10y ago
The erosion on the primary spillway is looking pretty nasty. Even if / after they manage to keep the emergency spillway from collapsing, they will probably need to continue running the primary spillway at a high flow rate to get the reservoir down to safe levels to ready for future storm systems and the coming snow melt, and this will continue to eat away at the hillside (they're currently dropping lake levels by 4" (!!) an hour). That's a significant outflow. It's a good thing that the spillways are decently far away from the actual dam structure. But it sure is going to be one expensive cleanup operation in the dry season.. Fingers crossed that things stay drier and cooler for the sake of all these people
kbutler 10y ago
Having grown up in a town that I saw flooded when the Teton Dam failed (http://www.history.com/topics/us-states/idaho/videos/engineering-disasters-teton-dam http://www.history.com/topics/us-states/idaho/videos/enginee...), I've been watching this closely. Thankfully, it appears the actual body of the dam is unlikely to fail, so hopefully even if the emergency spillway fails, it won't be a catastrophic, immediate draining of the whole lake.
ENOTTY 10y ago
I looked for more information about this situation. LAT has a live blog that seems to have some really good info about the dam, the spillways, and the damage in the early posts to the live blog http://www.latimes.com/local/california/la-live-updates-oroville-dam-how-the-oroville-dam-situation-became-a-1486958195-htmlstory.html http://www.latimes.com/local/california/la-live-updates-orov...
- Animats 10y ago
  The main spillway is out of action due to major erosion damage in its concrete flume. The power plant is shut down because the water level at the low end, in the diversion pool, is too high. So the two normal ways of releasing water are out of service. The emergency spillway is just a dirt hill near the dam with a concrete lip at the top. There's a data feed from sensors at the dam.[1] "Level" is probably good data. "Out" flow rate may not be meaningful; the emergency spillway probably lacks a flow meter. Here's a plot of "Level".[2] When it's below 900, the auxiliary spillway should stop flowing. As of 2330, it's at 900 feet almost exactly. [1] http://rdcfeeds.redding.com/lakelevels/oro.cfm http://rdcfeeds.redding.com/lakelevels/oro.cfm [2] http://cdec.water.ca.gov/jspplot/jspPlotServlet.jsp?sensor_no=1148&end=02/12/2017+23:31&geom=small&interval=2&cookies=cdec01 http://cdec.water.ca.gov/jspplot/jspPlotServlet.jsp?sensor_n...
  - PuffinBlue 10y ago
    The LA Times is pay-walled for me but here's a decent video from the last couple days that puts some visuals with the data you linked to: https://www.youtube.com/watch?v=EQSUJGzjmAI&t=0s https://www.youtube.com/watch?v=EQSUJGzjmAI&t=0s The video clearly shows the over-topping of the emergency spillway and the flooding/over-topping of the recreational area. It also shows the main spillway and the damage is obvious, particularly at the 22 minute mark. It's actually surprising how bad the damage is to the main spillway, it's not just a 'sink-hole' as was earlier described, it appears totally destroyed across a large portion of the middle part causing severe erosion of the land underneath and water spilling to the left side as well as rebounding up and over to the remaining lower section. This video shows the damage to the main spillway even more clearly: https://youtu.be/MFPuxGr7y6c?t=3m https://youtu.be/MFPuxGr7y6c?t=3m
CaliforniaKarl 10y ago
First, and importantly, my hopes go out to everyone that they are able to evacuate safely, and that nothing bad happens. I wonder, how do you test for something like this? I mean, you can certainly plan, and I imagine that the emergency spillway was examined at the time it was planned, but no plan survives contact with the enemy, and the best thing to do is to test. But, to test the emergency spillway you need to fill the dam to the point where it's overflowing, and I believe it's been a few years since we've gotten close to that. Certainly not any time in the last year. Besides, if it was tested in the past, it may be that the drought conditions--followed by all the rain--changed the soil in such a way as to enable this. I need to make a note to read the report when it comes out; I'm sure it'll be interesting.
- k26dr 10y ago
  The emergency spillway has never been needed before, so it's never had a chance to be tested by the looks of it
  - ChefDenominator 10y ago
    The rule for backups is that if you haven't successfully performed a complete restoration from backup, then you have no backup. Same principle seems to apply to spillways.
- manarth 10y ago
  There were concerns about the emergency spillway 12 years ago, but the request (to pave the emergency spillway with concrete) was rejected [1]. It was supposedly designed to handle 350,000 cubic feet per second, but began to fail at around 6,000 to 12,000 cubic feet per second. [1] https://news.ycombinator.com/item?id=13633395 https://news.ycombinator.com/item?id=13633395
toodlebunions 10y ago
Sooo how about that infrastructure bill the president wants?
- randycupertino 10y ago
  It would be nice if instead of wasting $20 billion on a wall we dont need to mexico we got actual public infastructure projects.
  - newman314 10y ago
    Agreed. However, watching the tweets trying to make this political has been sickening. The number of people wishing to "send liberals to Oroville" is nothing short of mind boggling. What. The. Actual. F?!?
    - Obi_Juan_Kenobi 10y ago
      Right!? I heard about this damage a few days ago and thought it was interesting, but now I find out there's this huge conspiracy scene around it. Stuff like 'the gov't is in CYA mode and trying to downplay risk' to 'this is a false-flag attack to undermine Trump'. It's just so weird that this seems to have people frothing at the mouth. How did so many collectively decide to adopt this narrative?
      - nosuchthing 10y ago
        If the bots and sockpuppet accounts on twitter are any indication of sockpuppetry among public internet forums than it's safe to assume there's a significant and non-trivial amount of postings coming from agenda pushing organizations.
      - pjc50 10y ago
        Oh, the frothing pre-dates Trump by a long way. It seems to be a self-sustaining mode in US politics, this deep paranoia about conspiracies.
      - 10y ago
jboggan 10y ago
4 months of record snowpack still to melt. It will be summer before any repairs can be seriously made.
- jeffdavis 10y ago
  Why? Can't they patch cement under water?
  - Obi_Juan_Kenobi 10y ago
    It's not a question of patching cement; you have to reconstruct the slope that's been worn away under the spillway. We're talking about huge amounts of Earth.
  - kbutler 10y ago
    Underwater, yes. Under a stream of water moving 65,000 CFS, ripping out chunks of solid cement, probably not so much.
ruffrey 10y ago
Following local news, it appears the greater Sacramento area should be OK even with a catastrophic failure to the emergency spillway. Between 130,000 and 180,000 people are being evacuated upstream.
lend000 10y ago
How difficult would this really be to fix? I imagine the most straightforward way to patch a hole, at least for a short period, is to use the water pressure to your advantage and inject objects to plug the hole from the dam side. Perhaps a thick metal plate lowered onto the main breach, and then malleable plastics/rubbers to slow seepage around the plate. Could probably push a hotfix out to master in a few days, for far less than 100 million dollars. Disclaimer: I haven't found any details on the design of the emergency spillway and the suspected damage, so this is speculation.
- etrautmann 10y ago
  The main dam has no holes, so there's nothing really to plug. This is not what's going on in this case. The erosion of the spillway isn't a failure of the main dam, it's just a badly damaged portion halfway down the hillside where they would be sending the overflow water. this means that the overflow water is causing even more erosion as it eats away at everything it's flowing around.
- simooooo 10y ago
  Upvote for hotfix to master
- jcranmer 10y ago
  Are you fixing it or are you making the inevitable failure even more dangerous? The answer is not easily determined. The current solution is to drain the reservoir of water as fast as possible--this removes pressure on the hillside, and reduces the scope for damage should the thing actually go. As for actually patching it, the solution is dumping lots of grout. But that only helps if the slope is actually stable and capable of supporting the embankment and dam. If the slope is washing away, all of your patching is just adding more weight to a structure that can't support its own weight anymore. While looking at old examples of dam failures, I came across https://en.wikipedia.org/wiki/Sweetwater_Dam#1916_failure https://en.wikipedia.org/wiki/Sweetwater_Dam#1916_failure ... this seems awfully similar to what's happening at Oroville right now.
  - lend000 10y ago
molecule 10y ago
> “Anytime you take on a situation like this where you seek to evacuate thousands of people on very short notice, it can be a chaotic situation,” Honea said. “We understand that.” > Sunday night gridlock as Marysville residents evacuate > After having to evacuate several times before, Agrifoglio said, she was used it. > She’s confident her husband will be able to evacuate if he needs to, but Tommy would have to wait out a flood. > Erin English of Linda said she got a robo-call a few minutes ago telling her to evacuate and get to higher ground. "The Wire: to evacuate": https://www.youtube.com/watch?v=h5d82ndui_s https://www.youtube.com/watch?v=h5d82ndui_s
bshimmin 10y ago
This is horrendous. I read this piece about the Mosul Dam (http://www.newyorker.com/magazine/2017/01/02/a-bigger-problem-than-isis http://www.newyorker.com/magazine/2017/01/02/a-bigger-proble...) a month or so back and found it very alarming, but wasn't sure how seriously to take it. I'm taking it more seriously now.
- sbarre 10y ago
  I thought about the same article when I read this.. It's a fascinating and terrifying read..
blubb-fish 10y ago
What was going on May 2016? Reservoir elevation at 891 feet. http://cdec.water.ca.gov/jspplot/jspPlotServlet.jsp?sensor_no=1148&end=02%2F12%2F2017+23%3A31&geom=huge&interval=720&cookies=cdec01 http://cdec.water.ca.gov/jspplot/jspPlotServlet.jsp?sensor_n...
- Amorymeltzer 10y ago
  Snowmelt. If you look even further back[1] you'll see that it's cyclical. Peak runoff these days is usually March-April[2], so by May reservoirs should be maxed out. The past few years have seen a major drought, so the curve can be pretty dramatic. 1: http://cdec.water.ca.gov/jspplot/jspPlotServlet.jsp?sensor_no=1148&end=02%2F12%2F2016+23%3A31&geom=huge&interval=720&cookies=cdec01 http://cdec.water.ca.gov/jspplot/jspPlotServlet.jsp?sensor_n... 2: http://www.abc10.com/weather/sierra-snowmelt-peaking-earlier/187931002 http://www.abc10.com/weather/sierra-snowmelt-peaking-earlier...
- maxerickson 10y ago
  That's typical seasonal variation, the snow pack melting. http://cdec.water.ca.gov/histPlot/DataPlotter.jsp?staid=ORO&sensor_no=6&duration=D&start=02%2F03%2F2012+06%3A11&end=02%2F13%2F2017+06%3A13&geom=Small http://cdec.water.ca.gov/histPlot/DataPlotter.jsp?staid=ORO&...
mrfusion 10y ago
I wonder about the idea of running some large hoses /pipes temporarily to help drain the water? Even a 3ft diameter would move a lot of water. Or I also wonder if they could drill into the bottom of the Resavoir and let the water drain into the ground?
- maxerickson 10y ago
  You are thinking on the wrong scale. The main spillway has been running at 100000 cubic feet per second. To carry that in 3 foot pipes (7 square foot cross section), you'd need hundreds or thousands of them (so a few just wouldn't do much of anything). Same with trying to bypass the water to somewhere else. To make a difference the bypass needs to be at a similar scale to the spillway, carrying tens of thousands of cubic feet per second.
  - hvidgaard 10y ago
    The worlds largest pump, located in New Orleans, cost $500 million, cannot move enough to match the spillway. You would need 5 of those to match the flow. But realistically, a pump that can move 10.000 feet^3/s would greatly reduce the stress on the rest of the pathways. Problem is, we cannot just rig up a temporary pump with that capacity.
    - maxerickson 10y ago
      It's even a pumping station, with 11 pumps. http://www.mvn.usace.army.mil/Portals/56/docs/PAO/FactSheets/WCC.pdf http://www.mvn.usace.army.mil/Portals/56/docs/PAO/FactSheets... Each can do 1740 cubic feet/second. And they are permanently installed and basically don't have anything resembling pipes.
- dzdt 10y ago
  See https://what-if.xkcd.com/147/ https://what-if.xkcd.com/147/. Niagra Falls is usually flowing at 100,000 ft^3/sec, the same as the spilway. Granted your 3ft pipe is a bit bigger than a drinking straw, but closer to the straw's scale than the spillway's!
rodionos 10y ago
Current Storage vs Capacity Levels: https://apps.axibase.com/chartlab/dee79515 https://apps.axibase.com/chartlab/dee79515 The overflow lasted for 45 hours. The water level appears to be dropping quickly at the moment: https://apps.axibase.com/chartlab/dee79515/2/ https://apps.axibase.com/chartlab/dee79515/2/
- anotheryou 10y ago
  Overflow means the actual spilling over the top (the emergency spillway) on to hill and street below? So we still have the broken main spillway in action or not?
  - hack_edu 10y ago
    Overflow over the top of a dam this size and type will almost certainly result in complete structural failure. The overflow we've seen so far is a secondary canal diverting excess water away from the main dam.
    - ChefDenominator 10y ago
      Is there an article discussing the dangers of continuing to use the main or emergency spillways? I'm not clear on why the downstream destruction is so dangerous. (And I apologize if it's completely obvious, maybe I'm just dense on this.)
      - tlrobinson 10y ago
        The spillway is damaged and eroding as water flows through it. As it erodes it opens up such that more water can flow, accelerating the erosion to the point where the entire hillside erodes away and the dam essentially fails.
        ChefDenominator 10y ago
        I can understand those concepts just fine, but when I look at the dam in Google Maps, it is not clear to me how this is specifically going to occur. The main spillway is on the hillside next to the dam, and the emergency spillway is on the same hill, yet further from the dam.
jordache 10y ago
This is reminisce of the spillway problem at the Glen Canyon Dam https://www.youtube.com/watch?v=dHpKvQ9XHV4 https://www.youtube.com/watch?v=dHpKvQ9XHV4 http://www.hcn.org/external_files/40years/blog/NearBreachGlenCanyonDamArticle.pdf http://www.hcn.org/external_files/40years/blog/NearBreachGle... It's a fascinating read. I'm sure the California folks right now are studying up notes from the Glen Canyon incident.
- VLM 10y ago
  It reminds me of Lake Delton in 2008, scaled up about seventy times larger.
- pilom 10y ago
  Glen Canyon was slightly different because there was no "emergency spillway" in the same way that Oroville has. Glen Canyon simply had 2 giant spillways that both needed to be in use but were both getting torn apart by cavitation. They ended up adding plywood along the top of the spillway gates to give themselves a little more reservoir capacity to wait out the flooding upstream but honestly they just got lucky. The only option they had at Glen Canyon if they exceeded the plywood barrier would have been to let water flow down the main spillways and possibly damage the dam.
Gravityloss 10y ago
Couldn't you just bring in a few oil / gas pipes (or whatever you happen to have) and siphon it in a more controlled manner? The country doesn't seem to have a problem in creating oil and gas piping networks quickly... 40 million cubic meters in 24 hours means just 15 2m diameter pipes running at 10 m/s. I would imagine the same amount of water flowing over a longer period time would cause less erosion even if the pipes wouldn't reach all the way down... Edit: You could even do it with 6000 20 cm diameter pipes, probably plastic would do.
- giardini 10y ago
  Gravityloss says> "Couldn't you just bring in a few oil / gas pipes (or whatever you happen to have) and siphon it in a more controlled manner? The country doesn't seem to have a problem in creating oil and gas piping networks quickly..." Good idea, but this is happening in CA, where pipelines don't sprout so quickly.
- etrautmann 10y ago
  I think the issue is the speed with which you'd have to implement a solution. It does seem easy, but maybe not to coordinate that construction to happen in less than 12 hours.
nbanks 10y ago
Is hydro more dangerous than nuclear? The Banqiao and Shimantan Dams killed 171k people, whereas Chernobyl killed 30 people directly plus an increase in cancer risk. No one died directly at Fukushima, though zero to hundreds could from radiation exposure depending on the estimates. About 18k died in the tsunami. (I just realized the Oroville Dam is for a reservoir rather than power generation, but the risks are similar.)

156 points by akaru 10y ago

TIL the Oroville dam is the highest in the USA, 44 feet higher than the Hoover dam. It's kinda mind boggling that it could actually fail tonight (though the latest reports indicate that the situation is improving).

aji 10y ago
to clarify: it's not the dam itself that's at risk of failure, but the emergency spillway. while this scenario would be catastrophic, it's far less catastrophic than the entire dam failing
- ChuckMcM 10y ago
  Think about that statement, what does is mean to you that the "emergency spillway failed" ? The ES is the portion of the dam that is slightly lower than the overall height of the dam so that in the event the main spillway was unable to release water fast enough, the water would start spilling here rather than across the dam. If it "fails" then a portion of the dam ceases to exist. That releases water through that hole uncontrollably. At which point losing containment is generally a matter of when not if. If it fails, it will be a double disaster, many people will lose property, and California will lose some or all of the water in its largest reservoir. The challenge is going to be keeping ahead of it through to the next storm.
  - khuey 10y ago
    The emergency spillway is around 30 feet high, the dam itself is 770 feet high. The amount of water released from a failure of the emergency spillway will be enormous, but still much smaller than the amount of water released by a complete dam failure.
    - k26dr 10y ago
      To clarify, the emergency spillway is 30 ft below the top of the dam, not 30 ft high
    - ChuckMcM 10y ago
      http://www.sacbee.com/news/local/article132356269.html http://www.sacbee.com/news/local/article132356269.html provides an excellent description of the challenge. The hillside where the emergency spillway is would be at risk.
      - verytrivial 10y ago
        Excellent link, thanks. I found the following comment sobering: "Countryman: It’s not going to be the (main) embankment failure, but it’s a failure. If it does happen, there’s nothing saying that the ground is going to stay where it is. That force of water will start tearing that hill apart, and it could eat back into the reservoir and drain the reservoir."
  - djcapelis 10y ago
    > California will lose some or all of the water in its largest reservoir Lake Oroville is actually the second largest reservoir and one of six reservoirs with a storage capacity over 1M acre feet of water: http://cdec.water.ca.gov/cgi-progs/reservoirs/RES http://cdec.water.ca.gov/cgi-progs/reservoirs/RES The largest is Lake Shasta: http://cdec.water.ca.gov/cgi-progs/stationInfo?station_id=SHA http://cdec.water.ca.gov/cgi-progs/stationInfo?station_id=SH... with a storage capacity of 4.3M acre feet of water, approximately 800,000 more acre feet than Lake Oroville.
  - Obi_Juan_Kenobi 10y ago
    > At which point losing containment is generally a matter of when not if. No, it's not. The local geology is fairly solid rock. The overflowing water will wear down the overlying soil and loose Earth, but should be sustained by the rock formation. It is a risk, certainly, but such a site is chosen because of the suitable foundation. The issue right now is to see how the spillway fares over the night. If it handles the increased flow, then it should be able to continue to relieve the situation. To be fair, I think it is a little ethically troubling to refer to the emergency spillway as anything other than that (e.g. auxiliary spillway), but it is designed to function in an emergency, not just fail catastrophically.
    - PuffinBlue 10y ago
      I'd love to get a source on this info. I've been looking for info on the geology of the exact area and the dam construction to assess this exact point. Where did you find the info on the area being solid rock? That would go a long way to giving an idea as to how bad any increased failure might be.
djcapelis 10y ago
So far, the only failure foreseen is to the auxiliary spillway which would definitely lead to an uncontrolled release of water from the lake, but is a separate structure from the main dam. There's definitely worries about the erosion on the main spillway moving back upstream towards the dam, but that is something folks are going to have to look at and consider over the remaining duration of the water season, unlikely to be a danger tonight.
- lisper 10y ago
  No, the emergency spillway is part of the dam. Failure of the spillway could lead to failure of the entire dam. It's not likely, but it's possible. Once large quantities of water start going where they weren't designed to go, all bets are off.
  - djcapelis 10y ago
    It certainly could, but they are literally separate structures, as repeated stated by the actual engineers who maintain the dam.
    - jcranmer 10y ago
      The hillside underneath the overflow spillway is literally washing away. You can see downhill portions of the spillway where the waters ate away 10, 20 feet of vertical elevation. If that erosion backs all the way up to the reservoir itself, then the lining could fail (much as the main spillway did). At that point, it doesn't matter if the dam is still standing, if there is a gash right next to it lowering the effective maximum water level by several feet. I don't know enough about the geology of the area to know how likely it is to happen. But history does show that dams can go very quickly once erosion reaches the dam/reservoir, so alarm isn't exactly unwarranted.
      - kobeya 10y ago
        It'll hit bedrock.

guard-of-terra 10y ago

https://www.youtube.com/watch?v=yhzKVdSnPmg https://www.youtube.com/watch?v=yhzKVdSnPmg Live coverage. They say situation is better now that drain is sufficient.

PuffinBlue 10y ago
That stream has now ended, but you can still see the live webcam feed: https://www.youtube.com/watch?v=hSaAE6MbKE0 https://www.youtube.com/watch?v=hSaAE6MbKE0 Not that you can see much as it's dark...

thatswrong0 10y ago

The erosion on the primary spillway is looking pretty nasty. Even if / after they manage to keep the emergency spillway from collapsing, they will probably need to continue running the primary spillway at a high flow rate to get the reservoir down to safe levels to ready for future storm systems and the coming snow melt, and this will continue to eat away at the hillside (they're currently dropping lake levels by 4" (!!) an hour). That's a significant outflow. It's a good thing that the spillways are decently far away from the actual dam structure. But it sure is going to be one expensive cleanup operation in the dry season.. Fingers crossed that things stay drier and cooler for the sake of all these people

kbutler 10y ago

Having grown up in a town that I saw flooded when the Teton Dam failed (http://www.history.com/topics/us-states/idaho/videos/engineering-disasters-teton-dam http://www.history.com/topics/us-states/idaho/videos/enginee...), I've been watching this closely. Thankfully, it appears the actual body of the dam is unlikely to fail, so hopefully even if the emergency spillway fails, it won't be a catastrophic, immediate draining of the whole lake.

ENOTTY 10y ago

I looked for more information about this situation. LAT has a live blog that seems to have some really good info about the dam, the spillways, and the damage in the early posts to the live blog http://www.latimes.com/local/california/la-live-updates-oroville-dam-how-the-oroville-dam-situation-became-a-1486958195-htmlstory.html http://www.latimes.com/local/california/la-live-updates-orov...

Animats 10y ago
The main spillway is out of action due to major erosion damage in its concrete flume. The power plant is shut down because the water level at the low end, in the diversion pool, is too high. So the two normal ways of releasing water are out of service. The emergency spillway is just a dirt hill near the dam with a concrete lip at the top. There's a data feed from sensors at the dam.[1] "Level" is probably good data. "Out" flow rate may not be meaningful; the emergency spillway probably lacks a flow meter. Here's a plot of "Level".[2] When it's below 900, the auxiliary spillway should stop flowing. As of 2330, it's at 900 feet almost exactly. [1] http://rdcfeeds.redding.com/lakelevels/oro.cfm http://rdcfeeds.redding.com/lakelevels/oro.cfm [2] http://cdec.water.ca.gov/jspplot/jspPlotServlet.jsp?sensor_no=1148&end=02/12/2017+23:31&geom=small&interval=2&cookies=cdec01 http://cdec.water.ca.gov/jspplot/jspPlotServlet.jsp?sensor_n...
- PuffinBlue 10y ago
  The LA Times is pay-walled for me but here's a decent video from the last couple days that puts some visuals with the data you linked to: https://www.youtube.com/watch?v=EQSUJGzjmAI&t=0s https://www.youtube.com/watch?v=EQSUJGzjmAI&t=0s The video clearly shows the over-topping of the emergency spillway and the flooding/over-topping of the recreational area. It also shows the main spillway and the damage is obvious, particularly at the 22 minute mark. It's actually surprising how bad the damage is to the main spillway, it's not just a 'sink-hole' as was earlier described, it appears totally destroyed across a large portion of the middle part causing severe erosion of the land underneath and water spilling to the left side as well as rebounding up and over to the remaining lower section. This video shows the damage to the main spillway even more clearly: https://youtu.be/MFPuxGr7y6c?t=3m https://youtu.be/MFPuxGr7y6c?t=3m

CaliforniaKarl 10y ago

First, and importantly, my hopes go out to everyone that they are able to evacuate safely, and that nothing bad happens. I wonder, how do you test for something like this? I mean, you can certainly plan, and I imagine that the emergency spillway was examined at the time it was planned, but no plan survives contact with the enemy, and the best thing to do is to test. But, to test the emergency spillway you need to fill the dam to the point where it's overflowing, and I believe it's been a few years since we've gotten close to that. Certainly not any time in the last year. Besides, if it was tested in the past, it may be that the drought conditions--followed by all the rain--changed the soil in such a way as to enable this. I need to make a note to read the report when it comes out; I'm sure it'll be interesting.

k26dr 10y ago
The emergency spillway has never been needed before, so it's never had a chance to be tested by the looks of it
- ChefDenominator 10y ago
  The rule for backups is that if you haven't successfully performed a complete restoration from backup, then you have no backup. Same principle seems to apply to spillways.
manarth 10y ago
There were concerns about the emergency spillway 12 years ago, but the request (to pave the emergency spillway with concrete) was rejected [1]. It was supposedly designed to handle 350,000 cubic feet per second, but began to fail at around 6,000 to 12,000 cubic feet per second. [1] https://news.ycombinator.com/item?id=13633395 https://news.ycombinator.com/item?id=13633395

toodlebunions 10y ago

Sooo how about that infrastructure bill the president wants?

randycupertino 10y ago
It would be nice if instead of wasting $20 billion on a wall we dont need to mexico we got actual public infastructure projects.
- newman314 10y ago
  Agreed. However, watching the tweets trying to make this political has been sickening. The number of people wishing to "send liberals to Oroville" is nothing short of mind boggling. What. The. Actual. F?!?
  - Obi_Juan_Kenobi 10y ago
    Right!? I heard about this damage a few days ago and thought it was interesting, but now I find out there's this huge conspiracy scene around it. Stuff like 'the gov't is in CYA mode and trying to downplay risk' to 'this is a false-flag attack to undermine Trump'. It's just so weird that this seems to have people frothing at the mouth. How did so many collectively decide to adopt this narrative?
    - nosuchthing 10y ago
      If the bots and sockpuppet accounts on twitter are any indication of sockpuppetry among public internet forums than it's safe to assume there's a significant and non-trivial amount of postings coming from agenda pushing organizations.
    - pjc50 10y ago
      Oh, the frothing pre-dates Trump by a long way. It seems to be a self-sustaining mode in US politics, this deep paranoia about conspiracies.
    - 10y ago

jboggan 10y ago

4 months of record snowpack still to melt. It will be summer before any repairs can be seriously made.

jeffdavis 10y ago
Why? Can't they patch cement under water?
- Obi_Juan_Kenobi 10y ago
  It's not a question of patching cement; you have to reconstruct the slope that's been worn away under the spillway. We're talking about huge amounts of Earth.
- kbutler 10y ago
  Underwater, yes. Under a stream of water moving 65,000 CFS, ripping out chunks of solid cement, probably not so much.

ruffrey 10y ago

Following local news, it appears the greater Sacramento area should be OK even with a catastrophic failure to the emergency spillway. Between 130,000 and 180,000 people are being evacuated upstream.

lend000 10y ago

How difficult would this really be to fix? I imagine the most straightforward way to patch a hole, at least for a short period, is to use the water pressure to your advantage and inject objects to plug the hole from the dam side. Perhaps a thick metal plate lowered onto the main breach, and then malleable plastics/rubbers to slow seepage around the plate. Could probably push a hotfix out to master in a few days, for far less than 100 million dollars. Disclaimer: I haven't found any details on the design of the emergency spillway and the suspected damage, so this is speculation.

etrautmann 10y ago
The main dam has no holes, so there's nothing really to plug. This is not what's going on in this case. The erosion of the spillway isn't a failure of the main dam, it's just a badly damaged portion halfway down the hillside where they would be sending the overflow water. this means that the overflow water is causing even more erosion as it eats away at everything it's flowing around.
simooooo 10y ago
Upvote for hotfix to master
jcranmer 10y ago
Are you fixing it or are you making the inevitable failure even more dangerous? The answer is not easily determined. The current solution is to drain the reservoir of water as fast as possible--this removes pressure on the hillside, and reduces the scope for damage should the thing actually go. As for actually patching it, the solution is dumping lots of grout. But that only helps if the slope is actually stable and capable of supporting the embankment and dam. If the slope is washing away, all of your patching is just adding more weight to a structure that can't support its own weight anymore. While looking at old examples of dam failures, I came across https://en.wikipedia.org/wiki/Sweetwater_Dam#1916_failure https://en.wikipedia.org/wiki/Sweetwater_Dam#1916_failure ... this seems awfully similar to what's happening at Oroville right now.
- lend000 10y ago

molecule 10y ago

> “Anytime you take on a situation like this where you seek to evacuate thousands of people on very short notice, it can be a chaotic situation,” Honea said. “We understand that.” > Sunday night gridlock as Marysville residents evacuate > After having to evacuate several times before, Agrifoglio said, she was used it. > She’s confident her husband will be able to evacuate if he needs to, but Tommy would have to wait out a flood. > Erin English of Linda said she got a robo-call a few minutes ago telling her to evacuate and get to higher ground. "The Wire: to evacuate": https://www.youtube.com/watch?v=h5d82ndui_s https://www.youtube.com/watch?v=h5d82ndui_s

bshimmin 10y ago

This is horrendous. I read this piece about the Mosul Dam (http://www.newyorker.com/magazine/2017/01/02/a-bigger-problem-than-isis http://www.newyorker.com/magazine/2017/01/02/a-bigger-proble...) a month or so back and found it very alarming, but wasn't sure how seriously to take it. I'm taking it more seriously now.

sbarre 10y ago
I thought about the same article when I read this.. It's a fascinating and terrifying read..

blubb-fish 10y ago

What was going on May 2016? Reservoir elevation at 891 feet. http://cdec.water.ca.gov/jspplot/jspPlotServlet.jsp?sensor_no=1148&end=02%2F12%2F2017+23%3A31&geom=huge&interval=720&cookies=cdec01 http://cdec.water.ca.gov/jspplot/jspPlotServlet.jsp?sensor_n...

Amorymeltzer 10y ago
Snowmelt. If you look even further back[1] you'll see that it's cyclical. Peak runoff these days is usually March-April[2], so by May reservoirs should be maxed out. The past few years have seen a major drought, so the curve can be pretty dramatic. 1: http://cdec.water.ca.gov/jspplot/jspPlotServlet.jsp?sensor_no=1148&end=02%2F12%2F2016+23%3A31&geom=huge&interval=720&cookies=cdec01 http://cdec.water.ca.gov/jspplot/jspPlotServlet.jsp?sensor_n... 2: http://www.abc10.com/weather/sierra-snowmelt-peaking-earlier/187931002 http://www.abc10.com/weather/sierra-snowmelt-peaking-earlier...
maxerickson 10y ago
That's typical seasonal variation, the snow pack melting. http://cdec.water.ca.gov/histPlot/DataPlotter.jsp?staid=ORO&sensor_no=6&duration=D&start=02%2F03%2F2012+06%3A11&end=02%2F13%2F2017+06%3A13&geom=Small http://cdec.water.ca.gov/histPlot/DataPlotter.jsp?staid=ORO&...

mrfusion 10y ago

I wonder about the idea of running some large hoses /pipes temporarily to help drain the water? Even a 3ft diameter would move a lot of water. Or I also wonder if they could drill into the bottom of the Resavoir and let the water drain into the ground?

maxerickson 10y ago
You are thinking on the wrong scale. The main spillway has been running at 100000 cubic feet per second. To carry that in 3 foot pipes (7 square foot cross section), you'd need hundreds or thousands of them (so a few just wouldn't do much of anything). Same with trying to bypass the water to somewhere else. To make a difference the bypass needs to be at a similar scale to the spillway, carrying tens of thousands of cubic feet per second.
- hvidgaard 10y ago
  The worlds largest pump, located in New Orleans, cost $500 million, cannot move enough to match the spillway. You would need 5 of those to match the flow. But realistically, a pump that can move 10.000 feet^3/s would greatly reduce the stress on the rest of the pathways. Problem is, we cannot just rig up a temporary pump with that capacity.
  - maxerickson 10y ago
    It's even a pumping station, with 11 pumps. http://www.mvn.usace.army.mil/Portals/56/docs/PAO/FactSheets/WCC.pdf http://www.mvn.usace.army.mil/Portals/56/docs/PAO/FactSheets... Each can do 1740 cubic feet/second. And they are permanently installed and basically don't have anything resembling pipes.
dzdt 10y ago
See https://what-if.xkcd.com/147/ https://what-if.xkcd.com/147/. Niagra Falls is usually flowing at 100,000 ft^3/sec, the same as the spilway. Granted your 3ft pipe is a bit bigger than a drinking straw, but closer to the straw's scale than the spillway's!

rodionos 10y ago

Current Storage vs Capacity Levels: https://apps.axibase.com/chartlab/dee79515 https://apps.axibase.com/chartlab/dee79515 The overflow lasted for 45 hours. The water level appears to be dropping quickly at the moment: https://apps.axibase.com/chartlab/dee79515/2/ https://apps.axibase.com/chartlab/dee79515/2/

anotheryou 10y ago
Overflow means the actual spilling over the top (the emergency spillway) on to hill and street below? So we still have the broken main spillway in action or not?
- hack_edu 10y ago
  Overflow over the top of a dam this size and type will almost certainly result in complete structural failure. The overflow we've seen so far is a secondary canal diverting excess water away from the main dam.
  - ChefDenominator 10y ago
    Is there an article discussing the dangers of continuing to use the main or emergency spillways? I'm not clear on why the downstream destruction is so dangerous. (And I apologize if it's completely obvious, maybe I'm just dense on this.)
    - tlrobinson 10y ago
      The spillway is damaged and eroding as water flows through it. As it erodes it opens up such that more water can flow, accelerating the erosion to the point where the entire hillside erodes away and the dam essentially fails.
      - ChefDenominator 10y ago
        I can understand those concepts just fine, but when I look at the dam in Google Maps, it is not clear to me how this is specifically going to occur. The main spillway is on the hillside next to the dam, and the emergency spillway is on the same hill, yet further from the dam.

jordache 10y ago

This is reminisce of the spillway problem at the Glen Canyon Dam https://www.youtube.com/watch?v=dHpKvQ9XHV4 https://www.youtube.com/watch?v=dHpKvQ9XHV4 http://www.hcn.org/external_files/40years/blog/NearBreachGlenCanyonDamArticle.pdf http://www.hcn.org/external_files/40years/blog/NearBreachGle... It's a fascinating read. I'm sure the California folks right now are studying up notes from the Glen Canyon incident.

VLM 10y ago
It reminds me of Lake Delton in 2008, scaled up about seventy times larger.
pilom 10y ago
Glen Canyon was slightly different because there was no "emergency spillway" in the same way that Oroville has. Glen Canyon simply had 2 giant spillways that both needed to be in use but were both getting torn apart by cavitation. They ended up adding plywood along the top of the spillway gates to give themselves a little more reservoir capacity to wait out the flooding upstream but honestly they just got lucky. The only option they had at Glen Canyon if they exceeded the plywood barrier would have been to let water flow down the main spillways and possibly damage the dam.

Gravityloss 10y ago

Couldn't you just bring in a few oil / gas pipes (or whatever you happen to have) and siphon it in a more controlled manner? The country doesn't seem to have a problem in creating oil and gas piping networks quickly... 40 million cubic meters in 24 hours means just 15 2m diameter pipes running at 10 m/s. I would imagine the same amount of water flowing over a longer period time would cause less erosion even if the pipes wouldn't reach all the way down... Edit: You could even do it with 6000 20 cm diameter pipes, probably plastic would do.

giardini 10y ago
Gravityloss says> "Couldn't you just bring in a few oil / gas pipes (or whatever you happen to have) and siphon it in a more controlled manner? The country doesn't seem to have a problem in creating oil and gas piping networks quickly..." Good idea, but this is happening in CA, where pipelines don't sprout so quickly.
etrautmann 10y ago
I think the issue is the speed with which you'd have to implement a solution. It does seem easy, but maybe not to coordinate that construction to happen in less than 12 hours.

nbanks 10y ago

Is hydro more dangerous than nuclear? The Banqiao and Shimantan Dams killed 171k people, whereas Chernobyl killed 30 people directly plus an increase in cancer risk. No one died directly at Fukushima, though zero to hundreds could from radiation exposure depending on the estimates. About 18k died in the tsunami. (I just realized the Oroville Dam is for a reservoir rather than power generation, but the risks are similar.)