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August West
Trad climber
Where the wind blows strange
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Feb 19, 2017 - 03:38pm PT
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Once the spring runoff is over all of the flow can go through the power plant and the outlet that goes through the dam.
So I would think that there will be repairs made on both the main spillway and the emergency spillway at the same time this summer.
I'm still curious about cost and how quickly they can finish.
If it drags into next winter how much of the lake will they drain?
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John M
climber
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Feb 19, 2017 - 03:57pm PT
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https://www.metabunk.org/oroville-dam-spillway-failure.t8381/
This thread was posted earlier. It appears to have some knowledgeable people on it, but thats not always easy to tell as not everyone identifies their background. A few have said it might take more then one year to rebuild the main spillway based on how long it took to build other spillways. One person said it could be done in one summer. If I remember correctly,, ( its a long thread ) that person did say that if they weren't able to finish in one summer, then they might build a hardened end on the main spillway up where it still remains and is connected to bedrock, so that it doesn't erode back up to the main spillway gates.
As for cost. I don't believe anyone knows. 1/2 a billion to one billion has been bandied about on the above thread.
I also found on that thread where they linked plans to the emergency spillway. Its hard to tell from the plans what exactly was done. But it appears that the emergency spillway is concrete and is probably built on bedrock. The problem was that the downstream side was not hardened. The plans seem to show it being concrete and one person who said they had an engineering background said it wasn't large enough to be a fill covered by cement. its size says it wouldn't have enough weight to hold back the water, so that person determined that it must be cement.
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neebee
Social climber
calif/texas
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Feb 19, 2017 - 04:29pm PT
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hey there say, DMT... wow, with more of a share on that
lake berryessa spillway hole, man oh man, :O
poor ducks, ??? if they get too close...
that sure doesn't seem good, yet:
it's been what?? operating for a long time?
man oh man, the things, we learn here,
at supertopo, :) ...oh my... :O
i am going to go read up on it, now, thanks
for sharing...
say, weather wise,
HOW ARE the dams holding up, right now, after the newest storm????
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neebee
Social climber
calif/texas
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Feb 19, 2017 - 04:32pm PT
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hey there, say, DMT...
wow, so far, just saw this...
news info, from 2 days ago:
SOME INFO:
http://www.wgal.com/article/california-lake-berryessas-glory-hole-to-spill-over-for-first-time-in-10-years/8947228
NAPA COUNTY, Calif. (SF Gate) —
For the first time in 10 years, water is expected to flow into Lake Berryessa's unique spillway, called the Monticello Dam Morning Glory Spillway -- but commonly known as the Glory Hole.
"A rough estimate is we expect it might start spilling tomorrow, Friday, or this weekend," McBride said.
The lake level was at 439.8 feet as of 9 a.m. Thursday and needs to rise about two inches to reach full capacity and kick the Glory Hole into full operation. PS:
(the article says, it DOES have a main spillway, as well--short but interesting news update)
...into the mouth of the 8-foot-wide pipe that dumps excess water down a 200-foot-long pipe into Putah Creek.
EDIT:
OOOPS, UPDATE, from one day ago:
http://www.mercurynews.com/2017/02/18/glory-glory-water-spills-into-glory-hole-at-lake-berryessa/
edit:
oh no! :(
Swimming near the Glory Hole is prohibited.[16] The exit of the spillway is well known in the skateboarding world as a full-pipe. Emily Schwalen of Davis died in 1997 after swimming toward the Glory Hole and getting sucked down the pipe.[17]
and, i had only wondered about ducks, :(
my condolences to the family, of so long agao, :(
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healyje
Trad climber
Portland, Oregon
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Feb 19, 2017 - 05:45pm PT
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You kind of have to be at least somewhat amazed at just how flimsy and minimal the main spillway design and construction was and that anyone could somehow think that constituted an acceptable engineering solution.
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neebee
Social climber
calif/texas
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Feb 19, 2017 - 05:53pm PT
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hey there say, ... another thought, for me...
i am suddenly wondering all the history, behind all these dams,
and what it was like, before them...
i am not really smart enough to understand all the tech stuff,
though, though i sure appreciate all the shares on all this,
as well...
you know, you just do NOT think about any of this, until:
the dams get over loaded, etc...
say,
JUST SOME STUFF, if anyone is interested...
https://en.wikipedia.org/wiki/Monticello_Dam
also, found this, --this is part TWO...
(but the other parts, must be around, as well) ...
http://napavalleyregister.com/news/local/death-of-monticello-was-a-heartbreaker/article_5a2687d8-ea83-11e1-a694-0019bb2963f4.html/
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neebee
Social climber
calif/texas
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Feb 19, 2017 - 06:12pm PT
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hey there say, ... me too, tami!!! ... very much interested in all this...
say, happy good eve, so nice to hear from you...
gotta run, now... night-night, will check
back later, :)
and many thanks yous, too, :)
to all, :)
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Sula
Trad climber
Pennsylvania
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Feb 19, 2017 - 06:15pm PT
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You kind of have to be at least somewhat amazed at just how flimsy and minimal the main spillway design and construction was and that anyone could somehow think that constituted an acceptable engineering solution. Yes.
And also with the approach toward inspection and readiness, which seems to be along the lines of "As long as nothing has failed, we'll assume nothing ever will. Inspections and backup plans are best put off until it's clear that you really need them."
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Reilly
Mountain climber
The Other Monrovia- CA
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Feb 19, 2017 - 06:15pm PT
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Tami, it doesn't swirl cause it just drops straight down and it doesn't matter once it hits the bend at the bottom - kinda like all the retards hitting the front door of Walmart on Black Friday.
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Chaz
Trad climber
greater Boss Angeles area
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Feb 19, 2017 - 06:30pm PT
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You have to forgive the water authorities for squandering the maintenance opportunity they had during the long dry period when the lake was practically empty. They probably believed the climate scientists who said we're in the midst of a 500-year drought, and figured they had all the time they needed to run out the clock to retirement without doing anything.
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Ed Hartouni
Trad climber
Livermore, CA
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Feb 19, 2017 - 06:58pm PT
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They probably believed the climate scientists who said we're in the midst of a 500-year drought...
where'd you read that, Chaz?
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Chaz
Trad climber
greater Boss Angeles area
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Feb 19, 2017 - 07:01pm PT
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You ever google something when you have a question about it?
Googling "california 500 year drought" turns up 870,000 results.
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Ed Hartouni
Trad climber
Livermore, CA
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Feb 19, 2017 - 07:02pm PT
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wow, and you believe every one of those?
why'd I ask, of course you do...
and you definition of drought?
certainly a wet year in 500 wouldn't matter much.
most of the top hits say that the current drought was the worst in 500 years, not that we're in the middle of a 500 year drought....
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tuolumne_tradster
Trad climber
Leading Edge of North American Plate
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Feb 19, 2017 - 07:46pm PT
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In response to Sula's & healyje's posts ^^^
In addition to engineering design flaws and construction and maintenance deficiencies, the underlying bedrock geology probably also contributed to the main spillway failure. It is evident from this photo and other photos posted on this thread ^^^ and the metabunk.org threads that the meta-volcanic bedrock beneath the main spillway varies considerably in terms of rock quality and erodibility. Not all bedrock is created equal. Unfortunately the evidence is gone, as the weak bedrock that decoupled from the spillway foundation anchors has been eroded away and transported down the Feather River. If you look closely, you can see the anchor bolts hanging from the spillway foundation.
Given that the bedrock units are primarily metamorphosed volcanic (primarily basalt) and volcani-clastic rocks of the Smartville Ophiolite Complex, the bedrock material that eroded from beneath the main spillway was probably "soft" and erodible due to hydrothermal alteration (i.e., chemical and physical alteration by caustic geothermal fluids that migrate along fractures and/or faults) common in ophiolite sequences. Additional recent chemical weathering may have further weakened the bedrock.
All this in the context of a series of atmospheric river storms following a prolonged drought...
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aspendougy
Trad climber
Los Angeles, CA
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Feb 19, 2017 - 07:49pm PT
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In the news today, they are talking about flooding on the San Joaquin river near Manteca; also there were vague references to flooding on the Merced and Tuolumne as well. Any locals have news?
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Ksolem
Trad climber
Monrovia, California
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Feb 19, 2017 - 08:07pm PT
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Scott Stine, a professor of geography and environmental studies at Cal State East Bay, has spent decades studying tree stumps in Mono Lake, Tenaya Lake, the Walker River and other parts of the Sierra Nevada.
Excerpted from an article citing his work, published in the San Jose Mercury News in 2014:
Through studies of tree rings, sediment and other natural evidence, researchers have documented multiple droughts in California that lasted 10 or 20 years in a row during the past 1,000 years -- compared to the mere three-year duration of the current dry spell. The two most severe megadroughts make the Dust Bowl of the 1930s look tame: a 240-year-long drought that started in 850 and, 50 years after the conclusion of that one, another that stretched at least 180 years.
Looking back, the long-term record also shows some staggeringly wet periods. The decades between the two medieval megadroughts, for example, delivered years of above-normal rainfall -- the kind that would cause devastating floods today. But Stine, who has spent decades studying tree stumps in Mono Lake, Tenaya Lake, the Walker River and other parts of the Sierra Nevada, said that the past century has been among the wettest of the last 7,000 years.
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rick sumner
Trad climber
reno, nevada/ wasilla alaska
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Feb 19, 2017 - 08:14pm PT
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^^^^That certainly puts the currently ended drought into perspective.
I wonder if there are accurate enough records of 1861-2 for comparison with this seasons precip. Immediately preceding the great flood of 1862 there was a much longer drought than this 500 year record drought Ed mentions.
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Ken M
Mountain climber
Los Angeles, Ca
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Feb 19, 2017 - 08:21pm PT
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You ever google something when you have a question about it?
Googling "california 500 year drought" turns up 870,000 results.
Chaz, if you google "green cheese moon", you get 1,230,000 hits. Must mean that the odds of the moon being made of green cheese is even higher????
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tuolumne_tradster
Trad climber
Leading Edge of North American Plate
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Feb 19, 2017 - 08:27pm PT
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According to the USGS ARkStorm report...
From an historical vantage point, USGS sediment research in the San Francisco Bay Area and also near Santa Barbara indicate that ‘ARkstorm-like’ floods have occurred in the past in the following years A.D.: 212, 440, 603, 1029, 1418, 1605, and then during the modern era in December 1861-January 1862. So we see a pattern of reoccurrence once every 165-400 years.
https://pubs.usgs.gov/of/2010/1312/
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Yury
Mountain climber
T.O.
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Feb 19, 2017 - 08:31pm PT
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Tami
The glory hole shown in the video there is a straight funnel.
Why isn't the design a counterclockwise spiralling thing?
I'm thinking that might make the water go down the hole with more efficiency. Tami, the opposite is true.
Water vortex decreases throughput.
You may conduct your own research next time you do your laundry or flush your toilet. :)
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