For those late to this thread and who didn't read the first page:
The Oroville Dam is the HIGHEST DAM IN THE United States!!
It is a rock filled dam that is 770' high
(the Hoover Dam holding back Lake Mead is 726 feet tall, 44' shorter)
Quoting: Anonymous Coward 52154903
To put into perspective the amount of water that was flowing down the Spillway today at the Oroville Dam when it started to deteriorate was about 60,000 cfs. (was scheduled to go to 70,000 cfs at noon, but that apparently didn't happen, or didn't fully happen)
That water was dropping approximately 640 vertical feet to the river below (about 550 vertical feet down the spillway and another 80-90 vertical feet over bedrock after the spillway ends to the river below).
Niagara Falls (Horseshoe Falls) which is the outflow for ALL the upper Great Lakes (Superior, Michigan, Huron, Erie) in contrast typically has a daytime flow of about 100,000 cfs (50,000 cfs at night) going over it's MUCH WIDER edge, but it only drops 167 feet to the river below, or less than 1/3 the vertical height of the Oroville drop.
If you have ever seen the water go over Niargara Falls then you can start to understand the amount of water and it's power that was involved with the Oroville Spillway failure today. It was 2/3 the amount of water with 3.5x the vertical drop - ie: a MASSIVE amount of erosive water power was involved.
It is going to be interesting to see what kind of plan they come up with to deal with this issue. To release water at the rate it NEEDS to be released is almost impossible imo without causing major serious damage, possibly into the dam structure itself. .... I fail to see how they can release water down the Spillway at those rates for the 10's of hours on end needed to keep Oroville Lake at a safe height when the hole under the spillway is already 80' wide, 30' deep, and possibly up to 200' long.
The lake theoretically could be allowed to run out over a lower level area off to the side (not inside the spillway) (parking lot area for the boat ramps), which would be an uncontrollable release, unstoppable once it started ... but who knows how deep of a channel it would cut through that dirt (or how far down the bedrock is under that dirt) until the lake level and the ditch channel would be at the same height. Hopefully that digging effect wouldn't go sideways enough to effect the dam's integrity.
This is potentially TRUE DOOM!!! since this is the Highest Dam in the United States!!
