When the levee breaks....Lake Oroville dam in trouble.

[TX Foilhead]

I think they want to get to 50ft, but they math says it's going to be more like 30.

 

[napanutt]

And now comes the next straw.

They NWS iand County officials are reporting an imminent failure of a Levee on the North fork of the Mokelumne River. This will flood some areas near Walnut Grove.

Waterjunky, cover your ass brother....

Yup.
http://www.sacbee.com/news/state/california/water-and-drought/delta/article132435374.html

 

[Member: 71]

Good to see the last minute pour of concrete on Friday held up.

 

[Uncle Dave]

Is the damage on the emergency spillway the blip at the end? - Its hard to get a handle on the emergency spillways "damage".


D

 

[Flying_Lavey]

Is the damage on the emergency spillway the blip at the end? - Its hard to get a handle on the emergency spillways "damage".


D

I believe so. Nowhere else along that gouge appears to be threatening the spillway structure. I gotta imagine with all that force behind the spillway, if it got a little closer it'd punch right through underneath it.

 

[wsuwrhr]

Gentlemen, keep the partisan side of the politics outta this thread please. Feel free to start a related thread in the appropriate section.
Lets keep this on target.

I don't want to start moving posts. I am rusty at it and might accidentally ban someone.

Accidently. Noted.

 

[TX Foilhead]

Is the damage on the emergency spillway the blip at the end? - Its hard to get a handle on the emergency spillways "damage".


D

If you go back a couple of pages the pics of someone's computer screen shows what appears to water flowing in the bottom of that spot, that would be the issue. When you see the scale of everything it's really hard to pinpoint a particular spot. I wish they would start dropping the bags once you can see where it will be easier to know the issue for sure.

 

[Mandelon]

We don't know how far down that concrete berm that is the emergency spillway goes down into the ground. If it sits on rock, then I would think it would be fairly unlikely that the water could "boil" through the underside of it.

For sure I would have heavy equipment in there filling any holes with riprap, and get our concrete guy back out there grouting them in place.

I would think a heavy pile of sandbags stacked on top of the berm could help direct flow away from that section that is nearly undermined. They would stay in place until the lake level got too high again...then they would just wash off the top.

The main spillway can go up to what... 150,000 fps? But if it is running too high, the power generation plant can run because the water backs upstream.

All this talk of repairing the main spillway at 100's of millions of dollars.... what for? It seems to be working pretty well under these extreme conditions. It would be cheaper to move the power poles than rebuild the bottom section. Once the flow is down to bedrock it shouldn't erode that much more...

I guess there's no political power to be had that way though... :rolleyes

 

[Uncle Dave]

If you go back a couple of pages the pics of someone's computer screen shows what appears to water flowing in the bottom of that spot, that would be the issue. When you see the scale of everything it's really hard to pinpoint a particular spot. I wish they would start dropping the bags once you can see where it will be easier to know the issue for sure.

Page 84 made all the difference thanks!

UD

 

[LargeOrangeFont]

This picture helps break down the issues and shows the emergency spillway and the compromised concrete spillway. The dam itself is not in danger.

 

[BajaT]

.

 

[Flying_Lavey]

This picture helps break down the issues and shows the emergency spillway and the compromised concrete spillway. The dam itself is not in danger.

The dam itself might not, but what is the substructure of the emergency and regular spillway? If those were to get undermined and collapse, that water could erode any soft material for God knows how many feet til it's solid bedrock and that bedrock won't allow anymore erosion. It's pretty evident in the erosion that has already occurred below the emergency spillway that there is definitely a fair amount of lose material ripe for the erosion by a large release of water.

 

[Mandelon]

That could likely let the top xx of feet come over......20 feet? 50 feet? eek:eek

 

[LargeOrangeFont]

That could likely let the top xx of feet come over......20 feet? 50 feet? eek:eek

Correct.. that is a ridiculous amount of water, but still not the entire reservoir.

 

[milkmoney]

The only thing that comes to mind, looking at all this water , is by May 1st Cali will say we have another drought. [emoji202]

 

[spark2678]

Weather Channel just did a nice in depth story of what is in the water over flow path from Oroville with dams and levies all the way to Sacramento. Pretty complex system that looks descent to handle a large issue. Mostly farm lands that would get wasted in extreme cases. Still a bad situation.

 

[was thatguy]

Didn't moonbeam just declare another 270 day extension for the official drought?

 

[dribble]

That could likely let the top xx of feet come over......20 feet? 50 feet? eek:eek

30 feet. The entire surface area of a 3.5 million acre ft lake 30 feet high.

 

[RiverDave]

Didn't moonbeam just declare another 270 day extension for the official drought?

The only thing that comes to mind, looking at all this water , is by May 1st Cali will say we have another drought. [emoji202]

That's the crazy part.. They will drain all the lake again and then say there is a water shortage? For the life of me I can't figure out why they do that?

RD

 

[Mandelon]

Can you imagine..... sheesh.

 

[Flyinbowtie]

They have started flying boulders.

The first bags they are dumping are way over in the corner where the dam road turns into the parking lot. Apparently that was the location of a leak...rumor is this will be a 24-7 job...we will see.
On the dam road, right at the end where the washout took place they have positioned a concrete pump truck.

 

[Yellowboat]

i hope the weather holds. heavy rains would stop every thing.

 

[TX Foilhead]

Yes, putting a bunch of rocks on it won't stop the problem, the hope is that it keeps it from getting worse while you lower the lake to fix it.

To the point about the dam being built on bedrock. Yes they should be, but that may not be the case or they may not have anchored it as good because it's not expected to see much if any use. This wouldn't be happening if the regular spillway was working properly. There is also the possibility that the water just found a way to get through the cracks in the rock, I'm sure they will figure it out once they figure out how to stop it.

Believe it or not dams leak, most of it is by design or in ways that don't have an effect on the integrity of the structure. The Dam where I work every day is a series of arches like Grand Coolie Dam, the arches spray water in spots and there are creeks running away from it. It freaks some people out an they won't walk near them. It is kind of weird to think about standing under +120 feet of water.

 

[Flying_Lavey]

Didn't moonbeam just declare another 270 day extension for the official drought?

Last I heard he wouldn't decide one way or another until the May snowpack readings.

That's the crazy part.. They will drain all the lake again and then say there is a water shortage? For the life of me I can't figure out why they do that?

RD

$$$$$

With a declaration of drought by the state government it allows the water companies to charge more per unit. A fairly descent amount more. Specially when you consider people have increased their water usage the last couple of months with the higher rates.

 

[TX Foilhead]

They have started flying boulders.

The first bags they are dumping are way over in the corner where the dam road turns into the parking lot. Apparently that was the location of a leak...rumor is this will be a 24-7 job...we will see.
On the dam road, right at the end where the washout took place they have positioned a concrete pump truck.

I would think that's a good sign that they already know where it's coming from.

 

[Flyinbowtie]

Getreal, this is your freebie. I asked earlier this morning that folks keep the partisan politics out of this thread. My personal beliefs aside, this isn't where we want this.
Start a thread in the appropriate section if you want to go here, please.
Keep this thread clean.

 

[Flyinbowtie]

Here is the website of the outfit providing the 60's. If you are an aviation junky like me you might enjoy spending a few minutes here.

http://www.pjhelicopters.com/helicopters/utility-hawk/

 

[Taboma]

Flyingbowtie --- Have you read or heard anything about evacuations being lifted ? A few relatives including my wife's sister were evacuated out of Plumas Lake last evening.

 

[Flyinbowtie]

Flyingbowtie --- Have you read or heard anything about evacuations being lifted ? A few relatives including my wife's sister were evacuated out of Plumas Lake last evening.

No I have not. I was told that the Marysville evac is now voluntary, but I know where Plumas Lake is, and I don't think they would have opened that area up yet. They should call Yuba County for precise information.
My gut tells me they won''t be letting folks back til they get a good feel for the situation up at the Dam, meaning the level of progress.
Best of luck to them.

 

[Taboma]

No I have not. I was told that the Marysville evac is now voluntary, but I know where Plumas Lake is, and I don't think they would have opened that area up yet. They should call Yuba County for precise information.
My gut tells me they won''t be letting folks back til they get a good feel for the situation up at the Dam, meaning the level of progress.
Best of luck to them.

I was concerned about my brother in law's Pietenpol Air Camper he spent 10 years or so building and he's got another home-built ?? in progress, but I guess he's got them hangered somewhere out of the flood zone.

Thanks

 

[Bobby V]

That's the crazy part.. They will drain all the lake again and then say there is a water shortage? For the life of me I can't figure out why they do that?

RD

Ground water plays a part of it.

https://agwt.org/content/drought-and-ground-water

 

[zhandfull]

I wonder if there was any sacrifices when they ramped up the damaged spill way to 100,000cfs. They said last week they lowered flow in damaged spillway from 75,000 to 50,000cfs to protect power line towers and the pump/hydropower plant. Haven't heard a word about either since they opened up the gates to 100,000cfs.

 

[Cray Paper]

This thread has been amazing on so many levels. Watching from afar but having some ties to the area and basic understanding of the scale of what is happening has been fascinating to me.

Several years ago a dam on the Columbia was in trouble, a crack became evident and the water level had to be dropped. it was a big deal in the local news even though it was on the other side of a mountain range and little impact to us on the western side. I just tried to pull up if it was fixed and stumbled upon this site.

http://www.hydroworld.com/articles/2014/06/grant-pud-updates-status-of-wanapum-dam-repairs.html

That link should take you to the 2 1/2" crack that opened up in one of the spillways.

If you refresh the site there is an update on the status of Oroville dam from this morning. What I heard clearly in that description is that the dam and intended and sacrificial spillway are separate structures. In my mind, with the current events, that means that bedrock separates the earth filled dam and the main and emergency spillways. They also mentioned a need to get the powerhouse back on line as a priority. Makes sense, if they can release water from the power house again it should assist with keeping the channel open to maintain releasing water from the power house and control the water level on the back side of the earthen dam.

 

[Carlson-jet]

I wonder if there was any sacrifices when they ramped up the damaged spill way to 100,000cfs. They said last week they lowered flow in damaged spillway from 75,000 to 50,000cfs to protect power line towers and the pump/hydropower plant. Haven't heard a word about either since they opened up the gates to 100,000cfs.

They were pulling the Powerlines down in a video I saw a few pages back I believe. They were just cutting them down pronto. Was interesting.

 

[HavasuHank]

Around 1300 is when I heard evacuations were lifted and people were being let back in.

It sux that some people are coming home to a looted house. Pisses me off.

Edit: I think the evacuations being lifted were in the area where our pipeline is ... not the immediate area of the damn dam.

 

[TX Foilhead]

I wonder if there was any sacrifices when they ramped up the damaged spill way to 100,000cfs. They said last week they lowered flow in damaged spillway from 75,000 to 50,000cfs to protect power line towers and the pump/hydropower plant. Haven't heard a word about either since they opened up the gates to 100,000cfs.

There is a set of towers just above the wall on the downriver side of the spillway. I thought they we concerned about the lay down yard towards the dam that was the concern and the reason to close the floodgates, but the towers were pointed out in the press conference yesterday afternoon. Once the power plant became unusable I guess they decided the transmission line wasn't that important for the time being.

 

[buck35]

This thread has been amazing on so many levels. Watching from afar but having some ties to the area and basic understanding of the scale of what is happening has been fascinating to me.

Several years ago a dam on the Columbia was in trouble, a crack became evidpreviouslyd the water level had to be dropped. it was a big deal in the local news even though it was on the other side of a mountain range and little impact to us on the western side. I just tried to pull up if it was fixed and stumbled upon this site.

http://www.hydroworld.com/articles/2014/06/grant-pud-updates-status-of-wanapum-dam-repairs.html

That link should take you to the 2 1/2" crack that opened up in one of the spillways.

If you refresh the site there is an update on the status of Oroville dam from this morning. What I heard clearly in that description is that the dam and intended and sacrificial spillway are separate structures. In my mind, with the current events, that means that bedrock separates the earth filled dam and the main and emergency spillways. They also mentioned a need to get the powerhouse back on line as a priority. Makes sense, if they can release water from the power house again it should assist with keeping the channel open to maintain releasing water from the power house and control the water level on the back side of the earthen dam.

was only a couple short years ago, I live on the pool directly above , they dropped the water 8 to 10 feet on ours to make power while dropping the next pool down by over 20 feet for the protection of the damaged dam. Couriously I had a pretty much free reign tour of this facility only months previous to this major event. Totally luck and being in the right place at the right time and knowing the right peeps.

 

[TX Foilhead]

This thread has been amazing on so many levels. Watching from afar but having some ties to the area and basic understanding of the scale of what is happening has been fascinating to me.

Several years ago a dam on the Columbia was in trouble, a crack became evident and the water level had to be dropped. it was a big deal in the local news even though it was on the other side of a mountain range and little impact to us on the western side. I just tried to pull up if it was fixed and stumbled upon this site.

http://www.hydroworld.com/articles/2014/06/grant-pud-updates-status-of-wanapum-dam-repairs.html

That link should take you to the 2 1/2" crack that opened up in one of the spillways.

If you refresh the site there is an update on the status of Oroville dam from this morning. What I heard clearly in that description is that the dam and intended and sacrificial spillway are separate structures. In my mind, with the current events, that means that bedrock separates the earth filled dam and the main and emergency spillways. They also mentioned a need to get the powerhouse back on line as a priority. Makes sense, if they can release water from the power house again it should assist with keeping the channel open to maintain releasing water from the power house and control the water level on the back side of the earthen dam.

Yes, there's a 'big ass rock' between them. It also sounds like the floodgate structure and the emergency (aux) spillway may not be tied together.

I'm having a bit of hard time myself, I'm use to seeing things that are maybe 200ft tall at most so I'm having a hard time with the scale of the pics.

 

[Taboma]

I understand this is the first time the Emergency (Aux) spillway has seen action.

The intended purpose is obvious, given the short duration it's been flowing and the ensuing damage as a result, what was the original
design criteria ?

What did they think would occur ?

I'm curious if in the Dam's operation manual it outlines in the protocol, that use of the Emergency Spillway will result in it's self destruction after X amount of hours ?

Apparently it had or has one purpose, save the Dam, even if it means catastrophically dumping 30' of lake level on the communities below. :eek

 

[Old Texan]

Anyone have links or data about current inflow and outflow? And water level

Edit- I think it's at 891' and close to 100K going out and 14K coming in from the site below. 96% capacity

http://cdec.water.ca.gov/cgi-progs/current/RES

 

[Her454]

As of this morning at 6 AM they are preparing 3000 pound bags of sand that they will be dropping with helicopters this afternoon. At 4am the water capacity was at 890.2 feet, down 12 feet from Saturday when it started dumping water over the spillway. 100,000 ft.per second continues to flow down the main spillway and the inflow has slowed down to 23,000 ft. per second. It's dropping 5 inches an hour this morning. The goal is to drop it 50 feet. Helicopters are getting ready to fly in about an hour and start dropping the boulders and the sandbags to repair the damage. Until that is done they said they are not ready to lift all evacuations. Obviously the rains coming in are a huge concern. According to all the news reports that I have seen Oroville is going to be one of the hardest hit.

On top of that, parts of Sacramento county are now being evacuated as another levee has failed at Tyler island near Walnut Grove.

 

[dezertrider]

Nearby Chico is predicted to get a little over 3 inches of rain in the next week

 

[Justfishing]

I understand this is the first time the Emergency (Aux) spillway has seen action.

The intended purpose is obvious, given the short duration it's been flowing and the ensuing damage as a result, what was the original
design criteria ?

What did they think would occur ?

I'm curious if in the Dam's operation manual it outlines in the protocol, that use of the Emergency Spillway will result in it's self destruction after X amount of hours ?

Apparently it had or has one purpose, save the Dam, even if it means catastrophically dumping 30' of lake level on the communities below. :eek

I think it serves a cpl of purposes. One of the purposes,of the dam is,flood control. The auxillary spillway provides a little extra storaget room. The 2nd purpose is the obvious,in that it gives a release point other than over the dam.


If it is stated that some damage is expected than I would say it is a last resort to EVER let water go over it. In this case no letting more water out was a choice made by the dam operators.


I would not expect the failure of the auxillary spillway is an option especially at the low volume that was passing over it. It was designed for at least 10x that amount of water in which case the water level would be even higher.

The lake is 15,000 acres at full pool. At the top of the auxillary spillway it even more. If the spillway is 20 feet tall you are talking in excess of 300,000 acre feet of water. Then you would have to take into account the downriver section is already strained and you are talking about inflows of 150,000cfs that would be passing through. Add to that you are above a major metro area.

I would say it is a major fail on the part of the,state not to upgrade the spillway in 2005. When looking at the erosion you seriously wonder how there was not a concrete apron.

 

[FreeBird236]

There is a set of towers just above the wall on the downriver side of the spillway. I thought they we concerned about the lay down yard towards the dam that was the concern and the reason to close the floodgates, but the towers were pointed out in the press conference yesterday afternoon. Once the power plant became unusable I guess they decided the transmission line wasn't that important for the time being.

One of the news reports I heard said the lines removed were not the main transmission lines. The design of this power plant doesn't allow any flow though without the connection. I'm sure you know more about that than I.

 

[boat527]

I think it serves a cpl of purposes. One of the purposes,of the dam is,flood control. The auxillary spillway provides a little extra storaget room. The 2nd purpose is the obvious,in that it gives a release point other than over the dam.


If it is stated that some damage is expected than I would say it is a last resort to EVER let water go over it. In this case no letting more water out was a choice made by the dam operators.


I would not expect the failure of the auxillary spillway is an option especially at the low volume that was passing over it. It was designed for at least 10x that amount of water in which case the water level would be even higher.

The lake is 15,000 acres at full pool. At the top of the auxillary spillway it even more. If the spillway is 20 feet tall you are talking in excess of 300,000 acre feet of water. Then you would have to take into account the downriver section is already strained and you are talking about inflows of 150,000cfs that would be passing through. Add to that you are above a major metro area.

I would say it is a major fail on the part of the,state not to upgrade the spillway in 2005. When looking at the erosion you seriously wonder how there was not a concrete apron.

An emergency spillway is just that.. used for emergencies... Its not for additional storage when its 20 feet below the top of the dam... Mother Nature and fate gave these guys ZERO choice.. There are no gates to control the flow over the " emergency -auxiliary" spillway.. When the lake level gets to 901 feet it just flows over, uncontrolled. End of story.

When they found the damage to the primary, they HAD to say F this, we have to get water out of the lake or it WILL come over the Auxiliary spillway, which it did a few days later.

Yes they can build the biggest spillway imaginable, but if those foothills got 4 or 5 inches of rain a day for weeks on end it still wouldnt stop flow from going down into the valley, just slow it down a bit.

 

[napanutt]

Here's a pretty good graphic of what they think is going on.

 

[Old Texan]

Here's a pretty good graphic of what they think is going on.
View attachment 539173

To me, that picture pretty much shows the shortcoming of ever thinking the emergency spillway could have ever worked "without" erosion. They're damned lucky the main spillway did the job of keeping the level below overflow. It's evident why evacuations were called for and the claim of 1 hour to failure was given.

The poor folks that had to deal with inferior design and gov refusal to fix what was a known flaw as recently as 2005, deserve great respect for overcoming these prior issues.

Hopefully the main spillway will hold for the upcoming natural weather events and real disaster is avoided. The goal must be to take the emergency spillway completely out of play. The only way it can ever be safe is a heavy well designed concrete shelf the entire length, narrowing down to a "ramp" to the river.

 

[was thatguy]

Yesterday headed west out of sac on 80.
[video=youtube_https;yKJ6zwWofHc]https://youtu.be/yKJ6zwWofHc[/video]

 

[Flying_Lavey]

This shit is so fascinating. The drama, the what if's, the huge consequences, the many possible outcomes, and the fact that this is only in the middle of February.

Our weather guy is predicting from this Thursday to Wednesday next next week our area can see up to 5" of rain. They've been holding Nacimiento at 790' which is 10' below full pool for this reason but after seeing all these events, makes me kinda wonder if 10' will be enough room for these crazy storms coming in and the soil being already super saturated.

 

[riverroyal]

Here's a pretty good graphic of what they think is going on.
View attachment 539173

my description from last week, in artistic form