Lake Oroville Rises Toward Damaged Dam
By Cliff M
Hi Jeff… Here are a couple of interesting possibilities to entertain. The dirt and debris that are now washing down from the broken spillway are creating a detritus dam at the bottom of the spillway. That dam is going to cause water coming out of the tunnels by the powerhouse to back up against the base of the dam. If it backs up enough it will weaken the base of the dam, due to reverse penetration of water. That situation will be compounded in magnitudes of 10 if the water in the lake overflows the emergency spillway and washes all the debris and soil into the riverbed, thereby creating even a larger detritus dam and causing more water to back up against the down-river side of the main dam.
This is unknown territory and all bets are off the table. The dirt and debris that are currently washing into the river bed, as well as any that might wash in from the overflow from the thousand year emergency spillway overflow, will also raise the bed of the river substantially, creating huge pressure against the diversion dam a couple miles downstream. My guess is, under those circumstances, that dam may likely fail.
Now here's another thought to consider. The water that is currently coming over the spillway and crashing into that hole and the jagged concrete edges of the remains of the spillway is creating HUGE sub -sonic vibrations that I am quite certain, are being carried through the mountain...to the dam itself.
Having been around huge amounts of cascading water such as this before and actually having seen the spillway in action before, I can guarantee you that the ground for miles around is shaking as if it were experiencing an earthquake. No one knows what effect those sub-sonic tremors and vibrations may have on the integrity of the dam. It may have no effect or it may be catastrophic. But so far, no one as far as I know, no one has considered or mentioned that potential issue. This gets better by the moment, and I can assure you the feather River will never be the same again.