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monolith
climber
state of being
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Feb 14, 2017 - 11:06am PT
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I was wondering the same thing, but I suspect that any access for trucks to that side was washed out.
Google Earth shows only 1 paved road which goes under the aux spillway and was washed out.
There is a graveled road on that side, but it may not be suitable for trucks and it looked like the aux spillway run off wiped it out as well.
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nita
Social climber
chica de chico, I don't claim to be a daisy.
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Feb 14, 2017 - 11:29am PT
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I wonder why they are using helicopters to fill those holes near the parking area? Why not use trucks and tractors? John, They are using trucks, tractors and helicopters...
Not sure if thse pictures have been posted.
http://blogs.agu.org/landslideblog/2017/02/14/oroville-dam-site/
Mei, That Fox video is well worth the watch..and does explain the dam situation pretty well.
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John M
climber
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Feb 14, 2017 - 11:41am PT
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Hi Nita, Yes.. I saw them using trucks on one side of the spillway. I was wondering about the other side where the boat launch and parking area is located. I didn't realize that the only access to that parking area is across the dam and then down below the emergency spillway. That road has been washed out.
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skcreidc
Social climber
SD, CA
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Feb 14, 2017 - 11:55am PT
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If there is "piping" occurring, they are in deep sh#t. Not sure they are going to be able to ascertain that in the time they have left. Filling up those holes with the largest rip rap they can find may be the best option as a temporary patch job.
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Jon Beck
Trad climber
Oceanside
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Feb 14, 2017 - 12:23pm PT
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When they want to get something done they can move mountains. Those freeway interchanges went up in a flash after the Northridge quake.
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Ksolem
Trad climber
Monrovia, California
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Feb 14, 2017 - 12:40pm PT
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And I don't mean that in the millennial-praise sense.
lol.
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nita
Social climber
chica de chico, I don't claim to be a daisy.
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Feb 14, 2017 - 01:44pm PT
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John M..My lunch break was over and i did not see your question..Looks like it got answered above by Mr D.^^T..
The Local late night news had reported they were building a road for trucks and heavy equipment, hence my reply to you on the prior page...
back to work
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monolith
climber
state of being
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Feb 14, 2017 - 03:48pm PT
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That's at 7am yesterday. I don't even see the new road there.
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August West
Trad climber
Where the wind blows strange
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Feb 14, 2017 - 03:55pm PT
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The damage if an earthquake hit sometime in the next week to 10 days would be huge.
From what I have read and heard, dams like Oroville aren't going to suddenly collapse in an earthquake. (Damage requiring expensive repairs might be another issue).
But from what I have read (and from an engineering buddy of mine who is involved in technical levee safety/assessment in CA) an earthquake could wipe out a lot of levees. If there has been an extended period of high flows so that the levees are a bit water logged and a big earthquake hits when the water is high up on the levees: the earthquake could cause the water to slosh back and forth and over the top of the levees. From what I have gathered, it doesn't sound like they are sure whether there would be a major problem or not. But if there was, it could be a huge deal.
When a levee fails, it is usually a section that might be a few hundred feet to a few thousand feet long. Once the water comes down, it can be repaired relatively quickly.
But a big earthquake might cause miles and miles of levees to all fail at once in the delta. That would take years and years to repair. Without the levees, salty water would make it upstream to the Tracy pumps. Not good for pumping water south.
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healyje
Trad climber
Portland, Oregon
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Feb 14, 2017 - 03:56pm PT
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The design below the emergency spillway wasn't thought through at all from the look of it - the road was guaranteed to go and the base of the emergency spillways was guaranteed to erode badly given they didn't give it any concrete ramp away from the emergency spillway itself. Should have been concrete at least as far as the road and channels should have gone under the road.
Nothing like building things gambling against big events and bothering with designing and building for one. Now it's going to cost way more than if they'd just built it right in the beginning. Probably would have been if it were sitting above Los Angeles and not nowhere NorCal.
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WBraun
climber
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Feb 14, 2017 - 03:57pm PT
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They should disassemble El Cap and helicopter it over to the dam.
That should fix it .....
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August West
Trad climber
Where the wind blows strange
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Feb 14, 2017 - 04:02pm PT
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The hole that was growing near the emergency spillway was the major reason for the evacuation, wasn't it?
The fact that they had a road there that got washed out is not a big deal. Replacing a short section of road once every 50 years, so what.
The fact that a relatively small flow over the emergency almost caused the concrete spillway to erode away is a big deal.
If the concrete spillway had collapsed, it would not have caused the entire dam to fail. But it sounds like the state engineers think 30 or more feet of the spillway would have collapsed. Better than having all 700 feet of the dam collapse. But still enough to cause some serious flooding.
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August West
Trad climber
Where the wind blows strange
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Feb 14, 2017 - 04:04pm PT
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If the spillway fails and releases 30 feet of water then the damn dam failed. Can't parse that away with engineering double talk about how the dam was in no danger of failing.
So how should they express that without causing confusion to the public?
Oh yea, we are on the verge of losing Oroville dam? Which means residents of Sacramento should be worried...
We are on the verge of losing 30 feet of the spillway, residents just downstream should evacuate but residents of Sacramento won't even notice...
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chainsaw
Trad climber
CA
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Feb 14, 2017 - 04:18pm PT
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I live in A downstream area. Our biggest concern is that water is coming through levees at Verona where the Sac and Feather meet. Alot of pressure down there.....garden highway closed and many trucks of rock and slurry gettin dumped. If the dam breaks, the result is predictable. But if it doesnt, when we get 5-12 in of rain this weekend, the levees may fail and we cannot predict for certain where. This has put our downstream communities on edge to be sure. Tractors and harvesters are stacked up on marcum overpass, stashed on high ground. Everyone is just waiting...
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tuolumne_tradster
Trad climber
Leading Edge of North American Plate
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Feb 14, 2017 - 04:57pm PT
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RE Dams & Earthquakes...
FYI, on May 12, 2008, the 8.0 M Sichuan (or Wenchuan) earthquake killed 69,000 people in Sichuan Province and left > 4.5M people homeless.
from Wikipedia...
According to a study by the China Earthquake Administration (CEA), the earthquake occurred along the Longmenshan fault, a thrust structure along the border of the Indo-Australian Plate and Eurasian Plate. Seismic activities concentrated on its mid-fracture (known as Yingxiu-Beichuan fracture). The rupture lasted close to 120 seconds, with the majority of energy released in the first 80 seconds. Starting from Wenchuan, the rupture propagated at an average speed of 3.1 kilometers per second 49° toward north east, rupturing a total of about 300 km. Maximum displacement amounted to 9 meters. The focus was deeper than 10 km
The reason I bring this up is that many geophysicists & seismologists suspect that this earthquake was the result of reservoir-induced seismicity...namely the rapid filling of the nearby Zipingpu Dam on the Min River triggered this large earthquake. Dams & reservoirs are not just passive objects that may be vulnerable to failure from a nearby earthquake...they actually induce earthquakes, if the filling of the reservoir is not managed properly.
http://science.sciencemag.org/content/323/5912/322.full
According to calculations by Christian Klose of Columbia University...
...the added weight both eased the squeeze on the fault, weakening it, and increased the stress tending to rupture the fault. The effect was 25 times that of a year's worth of natural stress loading from tectonic motions, Klose said. When the fault did finally rupture, it moved just the way the reservoir loading had encouraged it to, he noted.
Zipingpu Dam
Additional info here...
https://www.internationalrivers.org/resources/sichuan-earthquake-damages-dams-may-be-dam-induced-3619
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tuolumne_tradster
Trad climber
Leading Edge of North American Plate
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Feb 14, 2017 - 05:16pm PT
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This article appeared on the Temblor website today...oroville dam also at seismic risk.
An interesting question is whether after 5 years of drought, the large and rapid refilling of the Lake this winter—from 1/3 full to brim full—could set the stage for future induced earthquakes at the Lake. What this means is that both the spillway integrity and seismic resilience point to the same need for safety, strength, and vigilance.
http://temblor.net/earthquake-insights/oroville-dam-is-also-at-seismic-risk-2538/
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