02-13-2017, 10:03 PM
jdc wrote:
[quote=Ammo]
Here's some info about a somewhat similar situation: the Johnstown, PA. flood of 1889.
https://en.m.wikipedia.org/wiki/Johnstown_Flood
The main Oroville dam is in no danger of collapsing, so not really the same.
This one is little known, in S Cal -- and tons of peeps now live there -- https://en.wikipedia.org/wiki/St._Francis_Dam
I'm thinking that the dam itself WAS in danger. Not of a catastrophic collapse, but... maybe...
You can see their concerns: the 30' emergency spillway wall collapsing... that endangered the actual spillway. They were saying that if the erosion went that far, there would be 'uncontrolled release'. RIGHT next to the spillway is the dam itself. If the top of the spillway dissolved under intense erosion, the uncontrolled release of water would eventually start to erode support for the top of the dam structure and the dam wall itself might begin to crumble from the top down. It's not an impossibility. But if they even said it, 1,000,000 people downstream would have panicked and that might have been ugly.
Looks like they have things under control now - just hope they can release more water than will arrive in the next storm on Wednesday. I suspect they can.