California Drought

[California]

Over on Metabunk some knowledgeable engineers are posting.

This post is interesting, as well as those following:
Oroville Dam Spillway Failure | Page 5 | Metabunk

 

[coldsteelva]

Evacuations have been ordered. I guess the sky really is falling.

188K Ordered to Evacuate Near Damaged Calif. Dam | NBC Connecticut

 

[houstonscott]

Where's the governor? Hiding... Anyone think a few sandbags dropped from two helicopters is the fix. GET OUT! The fix was to do repairs during a 200 year drought when the lake was way down, oops. You couldn't drain that lake now if it was 100%, that snow pack alone will take all summer to drain. If that watershed gets heavy rain during a warm spring snow melt and yes a new channel could be cut and bye pass that dam and drain that lake quickly. That could destroy everything to the delta. I watched that dam being built as a kid, fly fished the feather before the dam and the lake after. Did a report in school about its construction. I know the area well.

 

[Buppies]

Where's the governor? Hiding... Anyone think a few sandbags dropped from two helicopters is the fix. GET OUT!

These type of comments belong in the political forum not here

 

[Egon]

Looks like the Orville dam has failed. Anyone watching this.... Water has migrated around dam completely and is draining the lake 3/4 of the way below the emergency spillway. Just time now. If main spillway can't drain lake quickly enough and there's not much chance of that now, there's going to be a catastrophe.

Looks like HS's prediction is comming to fruitation!!!

An aside question; can the owners of the water be held responsible for any downstream inconvenience?

 

[RedNeckGeek]

Looking out my back door to Lake Oroville I can see that there's still plenty of water, within a few feet of where it was yesterday at this time. I'm watching local news now 5:30AM Monday) and there is no indication of any flooding in the Feather River basin below the dam. That jibes with lake elevation data coming out of CDEC; the 5:00AM reading was 898.19'. That's almost 2' below the outlet for the auxiliary spillway, so it is no longer being overtopped. No word yet from DWR if the "boil" found late yesterday afternoon is still flowing. If it is it would be an indication that the auxiliary spillway itself is in the process of breaching, and that's the concern that triggered the evening's evacuations.

Thankfully the shameful fear mongering that's occurring here and across the Interwebs is just that. Officials continue to reiterate that the dam itself is not and has never been threatened. And this latest concern with the auxiliary spillway seems to be mitigated by the drop in lake level that was achieved overnight.

 

[houstonscott]

Looking out my back door to Lake Oroville I can see that there's still plenty of water, within a few feet of where it was yesterday at this time. I'm watching local news now 5:30AM Monday) and there is no indication of any flooding in the Feather River basin below the dam. That jibes with lake elevation data coming out of CDEC; the 5:00AM reading was 898.19'. That's almost 2' below the outlet for the auxiliary spillway, so it is no longer being overtopped. No word yet from DWR if the "boil" found late yesterday afternoon is still flowing. If it is it would be an indication that the auxiliary spillway itself is in the process of breaching, and that's the concern that triggered the evening's evacuations. Thankfully the shameful fear mongering that's occurring here and across the Interwebs is just that. Officials continue to reiterate that the dam itself is not and has never been threatened. And this latest concern with the auxiliary spillway seems to be mitigated by the drop in lake level that was achieved overnight.

That's good news, but you don't risk millions on a maybe. It's not fear mongering it just good practice and self evident there could be unknowns in front of us, the experts built the thing, look at it now...

 

[coldsteelva]

This dam is 'old' but is completely sound, HOWEVER the dam can only hold back water so long as the water remains below its top. The reason the emergency spillway exists is because there is a larger threat from a dam being overtopped and then failing. The emergency spillway is being used for the first time ever and it is evident that no maintenance or updating to make sure it too was 'sound' was ever done. Additionally, the long period of drought, would have killed off trees, grasses and other stabilizing growth and left the earth weakened along the emergency spillway. Also, the main spillway, which has a gaping hole, thus allowing water to undermine it and erode the area adjacent to the main spillway is also not sound. It seems that no money at all had been spent to study/evaluate/strengthen the main spillway ever. It's only purpose in life is to guide water to the river, but in your time of need, it fails as a result of water that it should have been designed to withstand.

I will never understand how CA does things.

 

[RedNeckGeek]

As a retired engineer my heart goes out to the people working to reason their way toward a solution. They are dealing with 40+ year old infrastructure and most of the people that designed and built it are no longer available to lend their experience and guidance to the effort. They're also up against Mother Nature and have no control over the path she takes. If these challenges weren't enough, the attitudes held by much of the press and the public are especially unfriendly to technology, especially that which impacts the environment. The biggest contribution this forum can make is to facilitate the dissemination of factual information related to the spillway failure to counter the fear mongering that's already going on and the witch hunts that will surely follow.

 

[Raspy]

As a retired engineer my heart goes out to the people working to reason their way toward a solution. They are dealing with 40+ year old infrastructure and most of the people that designed and built it are no longer available to lend their experience and guidance to the effort. They're also up against Mother Nature and have no control over the path she takes. If these challenges weren't enough, the attitudes held by much of the press and the public are especially unfriendly to technology, especially that which impacts the environment. The biggest contribution this forum can make is to facilitate the dissemination of factual information related to the spillway failure to counter the fear mongering that's already going on and the witch hunts that will surely follow.

Exactly. Well put.

 

[coldsteelva]

There should be no witch hunt. No single person is responsible for this failure. An institutional apathy is to blame. Infrastructure ages and weakens, concrete is not forever; just like we're learning from our nation's 'structurally deficient' bridges, you can't just set them and forget them.

No it is not cool to spend $100 million on maintenance of a dam, but how many billions are going to be lost now that that $100 million wasn't spent?

 

[Egon]

Evacuation orders should not be fear mongering. One has to assume there is basis for the evacuation order.

 

[prichard]

If it has been discussed I missed it but is there any concern or issue with the smaller dam between this one and Oroville?

 

[Raspy]

There should be no witch hunt. No single person is responsible for this failure. An institutional apathy is to blame. Infrastructure ages and weakens, concrete is not forever; just like we're learning from our nation's 'structurally deficient' bridges, you can't just set them and forget them.

No it is not cool to spend $100 million on maintenance of a dam, but how many billions are going to be lost now that that $100 million wasn't spent?

They recently inspected the spillway and found a few minor problems. Those were fixed. It seems they had no idea there was a weakness underneath that could allow it to collapse. There is no evidence that they deliberately skimped on maintenance or made some sort of gamble.

The real problem is the design of the emergency spillway. Just speculation here, but I bet they never thought it would be used. If they did, why make it spill onto a dirt slope? The erosion of that dirt is the obvious weak link here.

Another interesting thing about dam safety at several of the dams I've visited lately is the security related to terrorism. Each of the three I know about have big security measures, but no apparent maintenance upgrades. I'm not saying anything about weak maintenance at Oroville, just the fact that there seems to be a different emphasis where I've looked. I see equipment and infrastructure getting noticeably older and weaker, while more fences, tighter visitor rules and tighter security are evident. The pride and celebration of these magnificent structures is fading while fear is increasing.

 

[coldsteelva]

Well said, Raspy. Ever taken the 'old' Hoover dam tour where they would bring you inside and down to the powerhouse? Too many terrorism fears nowadays and things like that can't really be done. When I was in high school we took a field trip/tour of a nuclear power plant.

That stuff doesn't happen any longer.

 

[Raspy]

cold,

Hoover Dam is one of the places I had in mind. When I was a kid I was simply astounded at what I saw in there. A lasting impression I've never forgotten. Now it's all hidden away and they have a sort of shallow circus atmosphere that has nothing to do with the wonders of that place and the fantastic achievement to build it.

As I sit here this morning I have a sample of the transmission cable from there, sitting right here. The first time I visited it was about 55 years ago. The original builders were so impressed with the magnitude of it that they built a star map out of marble pieces that could be found thousands of years from now and put back together to establish a date of it's building. That lump should outlast the pyramids.

 

[buckeyefarmer]

I think they are doing the best they can with the hand they were dealt. Glad the emergency spillway has held, and people were able to get out. Dropping rocks in that washout about the best they have available right now. Looks like main spillway hasn't gotten worse any further up.

 

[aczlan]

Picture of the whole area with some good markings of where everything is to give some perspective:

Source: Twitter

Aaron Z

 

[Kyle_in_Tex]

You have to wonder if the higher ups might be holding back information to keep a full out pandemic situation from occuring. Thus, a smooth exodus.

Here on the gulf coast, they "over hype" hurricanes to get people to leave early.

 

[turnkey4099]

This dam is 'old' but is completely sound, HOWEVER the dam can only hold back water so long as the water remains below its top. The reason the emergency spillway exists is because there is a larger threat from a dam being overtopped and then failing. The emergency spillway is being used for the first time ever and it is evident that no maintenance or updating to make sure it too was 'sound' was ever done. Additionally, the long period of drought, would have killed off trees, grasses and other stabilizing growth and left the earth weakened along the emergency spillway. Also, the main spillway, which has a gaping hole, thus allowing water to undermine it and erode the area adjacent to the main spillway is also not sound. It seems that no money at all had been spent to study/evaluate/strengthen the main spillway ever. It's only purpose in life is to guide water to the river, but in your time of need, it fails as a result of water that it should have been designed to withstand.

I will never understand how CA does things.

They were removing trees and brush before the emergencyh spillway began flowing. Grass, trees, brush wouldn't stand a chance agains a rapid flow like that anyway, they would be gone in the first half hour. The trees and brush were removed to keep them from washing into the river..