Posted on 02/12/2017 4:26:47 PM PST by janetjanet998
Edited on 02/12/2017 9:33:58 PM PST by Admin Moderator. [history]
The Oroville Dam is the highest in the nation.
post 1105:
the little stream to the left of the main spillway is growing
seepage where?
and what do the numbers 9 and 21 mean?
it can be from the emergency spillway because the water level is well below that now
The eye opening thing to me is not the inflow or the storage, but rather the fact that they held the primary spillway at 60K CFS while the emergency spillway was being topped... they had so little confidence in the integrity of primary spillway that they were willing to let water flow over an emergency spillway that had never been used before.
Unsure.
Earlier on scanner there was also mention of no new cracks.
New flow on the left side of the spillway as you look up (first picture in your post). I can’t tell from the picture whether it’s coming from the spillway or if it’s runoff from the local rain. There’s a lot of exposed dirt over at the emergency spillway area that will present some runoff. Rain will run downhill and all that stuff.
its from the spillway
it started two days ago but got worse today
can’t be from rain since it cut a new channel and obviously its rained there before and that channel wasn’t there
Could runoff from the now hardscaped portion of the emergency spillway... finding a new path of least resistance
I can sort of see that, though the source gets lost in the steam/spray mist. It’s downhill from where the power line towers are, so that’s good. Probably just a new path from the original breach of the spillway. Maybe backing down has caused the water to fall straighter down (less “throw forward” if you will).
I’m kind of projecting here, but if you hold a hose horizontal and turn the water on low, the water will tend to fall almost straight down, but as you open the valve, the water pushes farther out as it drops to the ground. So maybe turning down the quantity of water had the same effect.
Re: 1268 - I was initially thinking that too. We’ll find out soon enough.
Re: 1262 - I think that a big part of those numbers on that chart have to do with the fact that the main spillway was damaged and they wanted to try to go without it. A few hours of scouring the hillside as water topped the “emergency/Aux) spillway told them that that was NOT an option. There was genuine concern that it would be compromised. Which is why the evacuation was ordered Sunday night (and I would say that was prudent).
They were spilling precious little in the early part of February and really didn’t open things up until they fully witnessed the damage that was caused by the overflowing water.
I suspect that there’s either been a change in leadership since Sunday, or the acting director learns very fast.
My theory is that they intentionally tested the emergency spillway while they still had an operative main spillway to end the overflow if problems were found..
That’s possible. I think that they panicked with the damaged main spillway and on a hope and a prayer, tried the emergency route.
Either way, problems were found!
https://twitter.com/CA_DWR
The only ones I trust are Scott Cahill and the Butte County Sheriff.
Especially when I see statements like this
“The dam is holding up, it’s structurally sound,” said Jay Smith, a spokesman for the California Department of Forestry and Fire Protection.
The Oroville Lake level has dipped to 869 feet, 32 feet below the top. “Everything is going well,” Smith told CNN, adding that “we’re cautiously optimistic.”
http://ktla.com/2017/02/17/heavy-downpours-likely-to-test-repairs-to-oroville-dam-spillway/
It will be interesting to see how they design/build/repair this summer. With respect to the e-spillway, they'll probably riprap and concrete a rough surface are covering the entire hillside.
The primary spillway will be very interesting. Since it appears there is solid bedrock under the spillway to the point of the break (thus allowing them to run @ 100k without significant back cutting towards the bridge), I wonder if they'll lay in multiple 15-20' thick concrete catch basins within the dugout ravine? Maybe they'll employ a ladder effect to allow the cascades to eventually reach the bottom with the confluence of the Feather river.
Scanner:
A crack in the slope above panel section 20
Crack not an issue right now but will be monitored.
Scanner: Copter about to cut another power line.
Evacuation advisories in central CA, levees are weakening
Highway 101 near Ventura northbound closed due to mudslides.
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