9757
From: pamela, [DNS_Address]
Subject: Current situation on Oroville
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see link- evacuations are still in affect... Officials Provide Monday Update Oroville Dam Emergency Spillway And Related Evacuations Published on Feb 13, 2017 Butte County Sheriff and Acting Director of Department of Water Resources offer the latest information on the damaged Oroville emergency spillway and the related evacuations (2-13-2017) |
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9760
From: JohnL, [DNS_Address]
Subject: Re: Current situation on Oroville - more details
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https://www.youtube.com/watch?v=wHDX7ejkpeM after 44 min. mark – shows Teton dam in Idaho collapsing in June 1976. 2 minute segment – commentator of Oroville dam video said that he thought the Oroville dam would also collapse. He said much more rain is in the forecast, and also snowpacks. The Oroville dam is about 70 miles north of Sacramento, Calif. http://www.vox.com/science-and- health/2017/2/13/14598042/oroville-dam-flood-evacuation This article explains the current situation. The main spillway was badly damaged, so the emergency spillway was used to release some of the excess amounts of water held back by the dam. Now the emergency spillway is getting damaged, but water flow through the main spillway is improving. Helicopters are dropping rocks to fill the holes at both spillways. Sandbags are also being used. The main spillway can allow much more water to be released than the emergency spillway. |
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9765
From: Polydactyl in N. Bay, [DNS_Address]
Subject: Re: Current situation on Oroville - more details
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My gawd, can you imagine the amount and variety of debris and sediment that will flood the SF Bay with even a partial collapse of the dam spillways, plus the watershed releases over the next 10 days of rain? Aquatic Park already is seeing driftwood all up and between the docks where the sea lions hang out. Their food supply is now further out with the fish taking a hike from the sediment. There's a picture out there of a huge sediment plume exiting the mouth of SF Bay and down flowing sediment for miles going through San Pablo Bay. The sediment won't bode well for marine life. It is now said that Monday will bring an atmospheric river type storm like the storm we had last time. The current storms are colder and won't drop as much rain, however, the Oroville area is likely to receive at least 10 inches of rain over the next 7 days. Imagine another storm coming again before the wet season is over too. I read some engineer comments that said the cement being poured has chemicals added to make it set faster but it didn't sound like Portland Cement that has heated clay and lyme added for underwater cement pours. There is another vid where they are talking to a guy named Todd who says the hole they are dropping rocks into is positively massive. He said they will drop rocks into the aux. spillway hole until someone tells them to quit. His admonition was 'stay out of Oroville' and that 5 inches of rain in Chico means 1.5-2 times that in Oroville. It's interesting to see the auxillary spillway where the cavitation happened due to their not being a lip at the bottom (called a 'comer'?). The first 100 feet or so has a solid parabolic wall drop that ends over very weathered bedrock so the water drops there and digs a hole! The rest of the aux. spillway has that lip but not much shoring up of the wall near the parking lot on top. They should've made the wall in front of the parking lot bigger so if water hits, it will go back towards the aux. spillway. The engineers and geologists knew in 2005 that the areal bedrock is not uniform and moderately to severely weathered, so that a huge incoming water flow can easily dissolve it. I guess they never thought we'd see real rain again or somethin'- ;) Then there's a glp'r remote vision of an event that until now she didn't know matched Oroville, to a 'T'. It doesn't end well and it's not at the parking lot where the problem is. The problem in in a spot that no one predicted. She got all the way to the event and someone reporting it, then saw a wall of water and said, I quit, don't want to see the rest. Oh, if her vision manifests, she said Sun.-Mon. there will be another full evacuation. It doesn't seem likely so hopefully it's a 50/50 situation with a 'heck NO!' result. It is said that 50 feet of water occurred with 15 inches of rain in the last storm. Now they have about 30 feet extra room from the current releases and are saying (officials allegedly) that they are expecting only 7.5 inches of rain over the next 7-8 days, to account for about half of the last lake increase, i.e., 25 feet, with five feet to spare. Hmmm, sounds a little too 'neat' doesn't it? The problem likely will start with the warmer front rain on Monday but we'll see. I know that one engineer dropping the rocks will be there until they drag him away. He's definitely on the worried side, despite their attempts to fill the holes with rocks and cement. The really big issue is if the main spillway fails, only THEN, it's game over. With any much larger release of water over the main spillway, there will be a bigger risk for it to crumble totally. The bedrock looks very flimsy under that section that failed. I would assume there are drains under that spillway that failed too, who knows. Fortunately the water going over the main spillway hasn't yet towed around back towards the dam face as they originally thought it might do. Whew. If they can complete the hole filling they can release water over the auxillary without too much drama, let's hope. Pray for NO DAMN DAM failure! The area is full of farms with animals and lovely almond and avocado trees- :( I'd be finding a way for my horses to hightail it outta there until the drama is over. Pray that the rain won't be as bad as much as they think, that the cement 'glue' will hold, and that any 'unexpected' holes will not develop, per the vision. |
9766
From: JohnL, [DNS_Address]
Subject: Re: Current situation on Oroville - more details
URL: http://sf.curbed.com/2017/2/13/14597746/oroville-dam-spillway-failure
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hi PolyD, thanks for the informative post about the Oroville dam situation. You mentioned: “…some engineer comments that said the cement being poured has chemicals added to make it set faster but it didn't sound like Portland Cement that has heated clay and lyme added for underwater cement pours.” ------------------ The main thing that might’ve saved my RV roof from leaks and snow a few years ago when rain just kept coming down, and water kept leaking in – was caulking the vents on the roof. The Portland maintenance man waited for dry weather and said the rain would not affect the water-proof caulk. Maybe they should’ve bought some Portland Cement. I had no idea how serious the Oroville situation was until I read about it on the internet, including Pam’s video. Your informative post mentioned warm rain, but not melted snow. I hope the main spillway holds. I’ve been studying a Physics tutorial which mentions Bernoulli’s principle which suggests that the water pressure where the spillway crack is will decrease when the velocity of the water is increased. At the end of March I’d hoped to visit my relatives in SF. It seems that Oroville is not too far from SF (150 miles). This links to an article on the spillway situation: http://sf.curbed.com/2017/2/13/14597746/oroville-dam- spillway-failure |
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9769
From: Polydactyl in N. Bay, [DNS_Address]
Subject: Re: Current situation on Oroville - more details
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Hi John, thank you for the link! Bernoulli's principle huh? Sounds like some hope is possible with increased water pressure and the partial shoring up of that hole- :) As long as any water doesn't dig a hole backwards into the face of either spillway. About that water proof caulking, probably depends on the conditions it's used more than the branded advertising about how wonderful some material is that allegedly is water proof. Branding is such a joke these days. The special cements are made by only a few companies so likely they pinch hit when they don't have time to get the real deal. A little Portland Cement could go a long way in the rain, I betcha- ;) With a good portion of the side rail ripped on one side, maybe the hole won't get bigger but the infrastructure may tear apart further down? It's hard to imagine the entire situation getting any better at the main spillway or aux. spillway, so the best one can possibly envision is that any 'event' does not cause a cascade of failure. The video I posted asks National Guard people who say they are setting up in MERCED! MERCED is below Sacto where people said all those weirs would stop the water. One of the weirs would direct water straight over to the David Univ. campus. They also used the words, 'eventual evacuation' as though they are expecting a catastrophe in slow motion. Lord have mercy. Well, at least the Ntl. Guard is taking into account the worst possible scenarios and that is not a bad thing. I do wish someone would sprinkle their magic drying dust on the entire region and stop the rain from ramping up. Today I saw another vid that compared the tsunami in Japan coming up into I think it was Minamisoma with the torrent of water pushing down the mountain side at the dam, that would take any buildings with it and knock out any people or animals in its way with incredible force. In the Japan tsunami it was amazing to see people turn around, stop and stare while hearing the water coming, like they were deer in the headlights! Makes you want to scream, 'Run up the hill, now!' at the video. In Oroville I guess it's best to scream, 'get on your horse and get uphill, now!'. My aunt said her family has gone through the mountains above and the valley below, many times, and says it's a lovely area. I can't imagine what SF Bay will look like when you come in March - yikes. |
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9761
From: Redhart, [DNS_Address]
Subject: Re: Current situation on Oroville - more details
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Their goal is to lower the lake by 50 feet by Wednesday night. That's when the next round of storms hit. They are doing it..to their credit. They have something like 30K gals/second water coming in and 100K going out through the damaged spillway. The difference is, well, making a difference--not only backing the lake away from the edges and emergency spillway, but reducing "pressure" on those structures as well. It's still going to be a long spring. All these fixes they're doing are temporary. They aren't really going to be able to get in there and fix it right until the spring rains end and the snow melt off subdued. While they have bought the northern california towns a reprieve from a very serious, life threatening flood for the moment, one very bad storm could turn it all around again in moments. I do hope they get it stabilized enough to allow everyone back to their homes. |
9770
From: Polydactyl in N. Bay, [DNS_Address]
Subject: Re: Current situation on Oroville - more details
| From most of the vids I've seen, many people are moving away right now with a permanent fix in mind, all except those who simply cannot move animals and a lifetime of investment into the house they retired to. Living away from all your 'stuff' gets old real quick. Let's hope the rest of Spring rain is not so bad. It seems like Spring already sprung! I'm not sure we can hope for a 'partial spillway' failure but that would be better more than holes developing under the spillways and compromising their support structures further. |
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9762
From: Jeff/Lake Almanor,CA, [DNS_Address]
Subject: Re: Current situation on Oroville - more details
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Hi Redhart, The link I provided shows the data of inputs and output up to yesterday the 13th. As of yesterday the inputs have gone down to 14441 cfs. Outputs at 99999 cfs. One cubic foot of water = 7.48 gallons of water. So as of yesterday, a staggering 747,992.52 gallons of water has been going down the spillway every Second. Mind boggling. |
9763
From: Jeff/Lake Almanor,CA, [DNS_Address]
Subject: perspective
URL: https://en.wikipedia.org/wiki/Olympic-size_swimming_pool
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An Olympic size swimming pool holds 80,000.00 cu ft of water. So 1.25 Olympic size swimming pools are going through the gates every second. |
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9764
From: Kat, [DNS_Address]
Subject: Re: perspective
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Pretty scary stuff...the snow hasn't even started to really melt! Snow Moisture content is also very high this year... hang on to your hats folks. |
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9758
From: eiluj, [DNS_Address]
Subject: A longer version of that video(NT)
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9759
From: pamela, [DNS_Address]
Subject: Re: A longer version of that video(thanks eiluj)(NT)
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