4 ms·

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

by 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
  Of course it wouldn't be a permanent solution, but allowing the hole to exist only makes it bigger in the short term. Anyway, the Sweetwater Dam article led me to an entertaining read about Charles Hatfield, the professional rainmaker: https://en.wikipedia.org/wiki/Charles_Hatfield https://en.wikipedia.org/wiki/Charles_Hatfield Now this guy was a great salesman. It leads you to wonder if his apparently high success ratio was a result of pure luck, if there's some truth to his "evaporative mix," or as suggested in the article, he had great meteorological prediction skills. If weather patterns are not independent one year to the next, then just the fact that only statistically significant drought-ridden cities call for his help probably suggests that all of these cities are "due" for rain regardless.
nrki 10y ago
The estimated cost to repair the primary spillway is $200mm: http://www.cnbc.com/2017/02/13/damaged-emergency-spillway-at-nations-tallest-dam-forces-massive-evacuations-in-california.html http://www.cnbc.com/2017/02/13/damaged-emergency-spillway-at... You can see the extreme damage in this photo: http://fm.cnbc.com/applications/cnbc.com/resources/img/editorial/2017/02/10/104275309-OrovilleDam_spillway_damage_Feb2017-b.530x298.JPG http://fm.cnbc.com/applications/cnbc.com/resources/img/edito...

by lend000 10y ago

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
Of course it wouldn't be a permanent solution, but allowing the hole to exist only makes it bigger in the short term. Anyway, the Sweetwater Dam article led me to an entertaining read about Charles Hatfield, the professional rainmaker: https://en.wikipedia.org/wiki/Charles_Hatfield https://en.wikipedia.org/wiki/Charles_Hatfield Now this guy was a great salesman. It leads you to wonder if his apparently high success ratio was a result of pure luck, if there's some truth to his "evaporative mix," or as suggested in the article, he had great meteorological prediction skills. If weather patterns are not independent one year to the next, then just the fact that only statistically significant drought-ridden cities call for his help probably suggests that all of these cities are "due" for rain regardless.

nrki 10y ago

The estimated cost to repair the primary spillway is $200mm: http://www.cnbc.com/2017/02/13/damaged-emergency-spillway-at-nations-tallest-dam-forces-massive-evacuations-in-california.html http://www.cnbc.com/2017/02/13/damaged-emergency-spillway-at... You can see the extreme damage in this photo: http://fm.cnbc.com/applications/cnbc.com/resources/img/editorial/2017/02/10/104275309-OrovilleDam_spillway_damage_Feb2017-b.530x298.JPG http://fm.cnbc.com/applications/cnbc.com/resources/img/edito...