California Drought

[California]

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This photo was taken yesterday morning when the spillway was shut down for inspection. It shows the exposed bedrock below the concrete, and I think I can make out some rebar in the concrete. Keep in mind you're looking across about 200' of material, 2/3 of a football field, so small details like rebar are gonna be difficult to see. Easy to understand that the water will continue to undercut the spillway concrete, but once it reaches rock it's not gonna go very much deeper.

Wow. I don't know anything about concrete, but retired from Caltrans (auditing contractors mostly) so I'm interested in this stuff. In my (uninformed) opinion the contractor there cheated and that looks like substandard concrete base beneath the spillway surface. The only time I've seen similar is third-world sidewalk that disintegrates after a couple of years. Do we have a civil engineer or concrete lab tech here who can support/refute this theory?

 

[dragoneggs]

Wow. I don't know anything about concrete, but retired from Caltrans (auditing contractors mostly) so I'm interested in this stuff. In my (uninformed) opinion the contractor there cheated and that looks like substandard concrete base beneath the spillway surface. The only time I've seen similar is third-world sidewalk that disintegrates after a couple of years. Do we have a civil engineer or concrete lab tech here who can support/refute this theory?

I was thinking the same... I don't see any rebar on the spillway base.

 

[aczlan]

Wow. I don't know anything about concrete, but retired from Caltrans (auditing contractors mostly) so I'm interested in this stuff. In my (uninformed) opinion the contractor there cheated and that looks like substandard concrete base beneath the spillway surface. The only time I've seen similar is third-world sidewalk that disintegrates after a couple of years. Do we have a civil engineer or concrete lab tech here who can support/refute this theory?

Some pictures of the broken concrete:

Source: Oroville Dam Spillway Failure | Metabunk

Aaron Z

 

[ultrarunner]

PGE is rerouting a power line tower with helicopters and trees on the emergency spillway are being removed... it had not been maintained and never used per news reports.

Looks like some bought into it would never rain again in California.

 

[California]

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Source: Oroville Dam Spillway Failure | Metabunk

Aaron Z

Metabunk. Never heard of it before but this looks like an excellent analysis. Have you linked to Metabunk on prior events/issues?

 

[houstonscott]

Anyone doesn't think this is a major failure and is just a small problem, is just who you don't want to listen to.... Because it is.... A warm spring and all that snow pack coming off in a month combined with rain, and you've got a disaster, and yes with enough water undermining this the dam might not fail but the whole thing could cut a new channel around the dam, real fast.

 

[TomSeller]

special kind of stupid there...

there is an experienced expert on everything

 

[aczlan]

Metabunk. Never heard of it before but this looks like an excellent analysis. Have you linked to Metabunk on prior events/issues?

Nope, just ran across it the other day looking for more info about the dam spillway problems.
Seemed well thought out, so I have been watching for updates.

Aaron Z

 

[dickfoster]

Where that damage in the spillway was is now a huge hole in the spillway and they just started putting water over the backup spillway this morning about an hour or so ago. One thing about living in CA is that you either have too much water or not enough of it so it's always on your mind or 90% of the time anyway.

A huge mudslide closed I 80 yesterday in both directions so they were running all that traffic on CA20.
Last night thousands of eastbound cars were running by the house on Scotts Flat Road trying to avoid the backup on 20 while they held all the big rigs leaving them with no place to go. I suppose because of the snow on CA20. Twisty, windy narrow roads with snow and trucks don't mix too well I guess. Hwy 49 is also closed just outside of Nevada City due to mudslides on both banks of the Yuba River. It's like hotel California around here, you can check it but you can never leave.

 

[aczlan]

Anyone doesn't think this is a major failure and is just a small problem, is just who you don't want to listen to.... Because it is.... A warm spring and all that snow pack coming off in a month combined with rain, and you've got a disaster, and yes with enough water undermining this the dam might not fail but the whole thing could cut a new channel around the dam, real fast.

We shall see where it goes. From what I understand the spillway and the emergency spillway are over an outcropping of bedrock so the water shouldn't be able to channel away enough to damage the dam itself or let water go around it uncontrollably.
That said, it will be a big project to fix it.

Aaron Z