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]
“J” wall still there. It’s just that the water was so high it was covered up. The whole main spillway structure is solid concrete and is anchored/imbedded in good solid bedrock.
If you zoom in on the photo in 1342 you can see that the rock is higher than the wall.
The approach wall might be a recent addition.
City and county administrators say they didnt have a dam escape plan prior to evacuation order
Oroville >> Butte County and City of Oroville administrators said they did not prepare an emergency plan in case of a spillway failure before the evacuation order of 180,000 surrounding residents was issued on Sunday.
The Department of Water Resources was ready for the scenario of if the dam broke but not for the magnitude of the spillway situation, said Paul Hahn, chief administrative officer for the county, after Fridays special meeting of the Board of Supervisors.
It is not something DWR anticipated, and I think thats something youre hearing, the frustration, Hahn said.
Oh, ok. It’s hard for me to judge the heights in the images. It looked to me that they were the same height. Thanks.
This image reveals a large 2foot diameter metal drain pipe buried under the footing elevation of the Emergency Spillway. This photo was taken before the flooding (overtop of the spillway). Notice the waterflow. A pipe of this size, and the angle it is projecting puts it underneath the ES Weir, would be unusual to drain the soil in the immediate vicinity (normal rainfall on the topsoil).
The Emergency Spillway blueprint design has the Weir as a concrete shell with aggregate fill. Drains are designed in the footing of the bottom of the aggregate horizontal to the elevation of the footing.
The blueprint design drawings indicate the Wier is sitting atop a rock foundation. But the type of rock may be what has been revealed in the deep cut erosion (hard rock but fractured or weathered rock).
What is also interesting is that this 2foot diameter drain is close to the opposite side of where the bubbles occurred. That drain pipe may have been a good indicator to any increased water underflow to the substructure of the ES Weir when flood levels occurred (just before and just after the cresting of the Weir).
I can’t believe water from multiple directions is allowed right at the gate. It’s begging for trouble. The approach wall should be at least as high as the auxiliary spillway.
Here is something of note - From the archives of the DWR Oroville Dam, page 93:
States the maximum probable flood has a probability recurrence in EXCESS of ten thousand years. (where both the Emergency Spillway and the Main Spillway would operate together - from high reservoir inflow).
Going offline for a while.
The word “sociopath” seems to be getting a lot of use recently. ..but in this case it seems apt.
Here is the latest view of this 2 foot diameter drain pipe. Pic taken while Emergency Spillway construction underway (rock spreading and concrete trucks at the ready).
Looks like the early stages of the emergency repairs before the rains moved in (sky is bright & overcast). Dumped rock, soil, and base weathered rock around CAT excavator look dry (not saturated, wet, or fresh rain soaked). Water is flowing from somewhere, albeit minor. Just more tidbits.
God’s bulls-eye?
“Water, contrary to popular belief, does in fact flow uphill.”
That’s what our water “authorities” don’t seem to understand so can only assume “authorities” all over the nation don’t either. A bit of a different uphill is when there is a flood at my house. It doesn’t much matter about the dam and spillway up stream when the water is coming in from rivers and tributaries down stream. When those flood, the water spreads in all directions to find its level. The waters will turn uphill. I can watch the wave moving up stream. My particular area, the river width is bottle necked so the flood wave gets higher as it squeezes through.
Then they’ll inevitably open the dam gates above us so when that water meets the back up flood wave.... well, it’s fun. The so called “authorities” will argue with us that they’re not flooding us out because they’re looking on their computer models (2 hours away) which shows the gauges in the main lake at safe levels. Back in the day, there were human monitors on site who did a much better job than computers.
“If the rain forecast is expected to be up stream from the dam itself they may dodge a bullet.”
Any rain upstream will flow down into the lake if the soil is already saturated. You can get flooding with rains 2-3 counties away.
Underflow would threaten the main damn structure, right?
Underflow would threaten the main damn structure, right?
Brown or Brown’s brown water is not good!:)
Is the draining water coming from ‘under’ the dam? Watch this:
Model Dam Fail
In this case, it would threaten the aux/emergency Weir and not the main dam. Which is still a very bad thing, because while the dam would survive, losing the weir would result in a washout of a good amount of ground that would bring a lot of water down at one time.
I don't think that the water dribbling out of the 2 foot pipe is necessarily a bad thing. The area has had a lot of rain and the ground is saturated. This could easily be just excess water that has soaked into the area soil. Depends on where the drain goes.
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