Posted on 02/14/2017 3:04:08 PM PST by CedarDave
Five separate videos shot by CA DWR as the emergency spillway becomes active (overtops) at 8:a.m. on Saturday morning through Sunday p.m., and work on Monday to drop rock to fill the erosion channels. Most videos are from drones and the relationship of the spillway to the main spillway on the right (direction southeast) and the parking lot on the left (direction northwest) can be easily seen.
It appears that the fear of failure of the emergency spillway was two-fold with erosion moving back up to the narrow base of the spillway and possibly undercutting the concrete spillway, and the possibility of a new lake outlet at left end of the spillway due to flooding of the parking lot and subsequent scouring back to the lake.
Two days old.
Thank you.
So what they are saying here is that they never keyed that spillway all the way to bedrock? Then if not, they should have dug out the front of that spillway and set down a cement apron that slopes away from the spillway to get that water to run away from there. And when I say a cement apron, I MEAN A APRON! Ten feet thick at least at the spillway base-at least.
As for the parking lot..that should have been built up several feet to crowd that water towards that spillway.
This was/is another engineering disaster that was in the making. Their thinking was, oh it’ll never get that high since we have this primary discharge and that will take care of it. They failed to repair the chute out from the primary discharge and it broke up and on it went from there.
Looks beautiful.
Yes, before they use that spillway again they will have to prevent water from moving laterally onto the parking lot where it will spill down the slope and scour back to the lake.
Thanks. Great video quality there.
What gets me, is that there seemed to be no planning for how the emergency spillover portion would move down away from the dam. I guess they never thought they’d use it.
There should have been a concrete channel provided to carry that water down the hillside.
Would have stopped a lot of erosion.
One other issue seemed to be that the emergency spillover didn’t seem to be blow the other portions of the dam. For instance the parking area was flooding over.
The emergency spillover should have been several feet lower than than the parking lot.
What I want to know is who closed the airspace above the dam as soon as the emergency spillway was overtopped.
The hill was clearly eroding too much and the government kept the public in the dark until Sunday afternoon when the story changed to ‘run for your lives’.
The CYA was deafening...
WTH?! The whole thing should be built up, except the height of that spillway, to the height of the main dam. It looks to me that they built the dam and then said, OK, lets put this thing over here and that’ll do it.
You can NEVER force water to do what you want, you can only coax it do what you want.
I am telling you now..and I hope one of these people are paying attention on here. My biggest fear now is-MUDSLIDES above that dam.
They had better have people up on those hills, if there are hills up there, taking a look at the stability of the banks up there.
The dam is secure now-at least it seems so, but if there are steep banks above there...
So, a tsunami type wave event eh?
You and I could do a better job of design than they did!
I watch those vids and go WTF!!
One more..it looks as if they got 90 degree angles on EVERYTHING. You and I know what high force water does to 90 degree angles?
You NEVER put such angles on high force hydraulics because it is a restriction. Always gentle slopes.
They are GD lucky the ground sloped away from the parking lot area the way it did...gently.
I grew up in a mining town FULL of construction workers, pipe fitters, welders, and heavy equipment operators and I know stupid when I see it. Why they didn’t start first by building a ramp off of the end washed out road down into that area below the emergency spillway to just dump things by truck instead of relying helicopters I’ll never know. The engineers must have all went to Harvard, Yale, or Stanford to be that goddamned dumb.
There should have been a road (bridge) completely across the whole width of the thing (dam) all the way to the parking lot.
Like you said, they got no access the thing now until they rebuild the road.
Do you want to put people and equipment below a potentially fatally weakened dam?
I do not.
The real danger on the emergency earthen runoff area is those deep erosive cuts in the soil, working their way back to the concrete weir, especially on the far left side (looking from the downriver side of the dam). Once those erosive cuts reach back to the weir, water can come under the weir and erode the soil underneath. At that point, the weir is at best, underpassed by a 30 foot wall of water or at worst, toppled by it. That is the 1st nightmare scenario. A 30 foot sudden drop in the reservoir level will put Oroville under 100 ft of water.
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