Oroville Flood

Wow, that's a lot of water...!

It will be a relative miracle if the leakage doesn't lead to a (serial disaster)...

At least the damage (so far) is only to the spillway rather than to the dam proper.

The drive down the Feather River is amazingly scenic.

That would be only the VISIBLE damage...

All the water coming out of the (hole) has seeped into the earthen portion of the dam from the impounded water behind the concrete portion of the dam...

Any student, in their (first soil engineering class), should recognize this as ''piping erosion'' behavior, ironically...

And every body, and every thing, down stream is in imminent danger of system-wide collapse of the dam, proper...

It could become criminal negligence not to immediately evacuate all the nearby, low level, housing occupants, because the extent of the (piping erosion) is not completely known...

Heaven save us all from such (experts ?...) that say otherwise...

That's possible, of course; and if so, more worrisome.

I have to agree with MR. GUEST, that this damage is most likely caused by "Hydraulic Piping" through the earthern backfill portion of the dam proper. That is NOT a good sign, as the remaining portion of the dam may have been compromised as well.

Spot on Mr. Guest!

How might hydraulic piping traverse the impervious core shown in post 40?

... and the bedrock in the hill between the dam itself and the spillway?

I haven't yet seen details specifically on the ends of the dam, but I have seen videos of how they excavated and hydraulically washed down to bedrock at the base of the dam during construction. I have to believe that they did the same at the ends of the dam, or they would have made the dam longer.

I have also seen images of them working on the spillway in 2009 and 2013. In the 2013 images, they were clearly working on the same section that first failed in the current disaster. It certainly appears that they put a bandaid on a major wound without disinfecting the wound!

I continue to hold the belief I posted in #17.

Tornado, a majority of U.S.-built earthern dams feature a impervious core constructed of Bentonite clay placed in lifts (layer) and compacted with sheepshead rollers, as a specified Moisture Content (MC).

It is not fool-proof, and the design is Empirical at best, based on past performance histories of such dams. The MC has to be spot on within a certain range and that requires round-the-clock field testing. There is also the possibility that the compaction was not thoroughly complete at the interface between the Lifts. Hence, there would be seepage occurring at the numerous Lift Interfaces, increased naturally by the high impounded water surface level behind the dam.......higher soil porosities undoubtedly are presently occurring.

As you will notice in the illustration in Post #40, there is an underdrain blanket to collect seepage from the wet side of the core, but if it should become clogged the water pressures in the soil voids will become much higher than normal.

Look up "Groundwater Hydraulics" for more information.

It's also possible that the initial failure occurred in a badly constructed Construction or Expansion Joint in the spillway, which allowed water to intrude at a high rate into the underlying soil subbase material, enabling the erosion and wash-out.

And this would not have occurred to any of the persons on scene?

Hey, they're GovMint Civil Service Employees! What did you expect? LOL

And you never worked for the goobermint?

The point CaptMoosie is making, is accountability amongst civil servants is next to 'nil'.

And at least the ones I've dealt with. Wnem their designs fails, the civil servants that designed it, are somewhere else. Usually promoted for reasons unknown.

Thank you Phoenix911. Yes, what you have stated is entirely true about Civil Servants. If you can pass the Civil Service Exam you are normally untouchable, unless you seriously screw the pooch, like getting persons maimed or killed.

To answer a previous post, yes, I was once a City Engineer in upstate New York and know a thing or two about the inner workings of GovMint and Civil Service wranglings and a ton of loopholes once an appointed Employee has passed the "grace period".

That said, let's move on to the real issues at hand regarding the possibility of the impending Oroville Dam failure.

I stand on my previous statements on the failure of the existing concrete primary spillway. The Emergency Spillway damage is an entirely different matter. I feel that it's failure is due to high volumes of water (and hence velocities), highly erodible soils, and inadequate stone rip rap channel protection. Just a very poor design. At lest not a conservative design.

Somebody forgot to (tell) the (concrete?) core it was supposed to stay impermeable...

What evidence has been shown that it hasn't stayed impermeable?

Actually, given the height of the (leakage) through the spillway, the water may well have (seeped) over the top of the core material, at first...

If the dam somehow survives long enough, maybe a little forensic geotechnical engineering effort can be made to determine more specifically the exact mechanism(s) of failure...

... and whether or not other such failure mechanism(s) also contributed...

By what ever means, Oroville and 7 downstream cities have been ordered to be evacuated...

"given the height of the (leakage) through the spillway"

Which spillway are you referring to?

I believe leakage through the cracks/joints of the main spillway at least contributed to, or possibly initiated the original failure, but I don't know how one could speak about the height of that leakage. ...perhaps the height of the leak location above the river?

If you are talking about the emergency spillway, then what evidence do you have that there was leakage/seepage through the concrete of that spillway? Again, if there was leakage through that spillway, I'm still not sure what the height of that leakage would mean.

Then you talk about "the top of the core material...". That makes me think you are talking about the dam itself, since neither spillway has anything I would call a core, but the dam itself does.

All of the above makes me think you don't understand the construction of this facility.

The only thing one can do with a pet theory is pound it to fit and paint it to match.

No,... Actually,... both your previous posts are speculative.

Of course they are speculative...

Competent geotechnical engineers have not completely investigated and reported yet...

Obviously, I was referring to this threads' two, side-by-side, original photos...

More recently, news film shows leakage under both spillways, so pick which ever spillway you like...

Has Mt. Helens (rumbled) any, recently?...

When it does, and it will, just tell it to stop...

Because you said to...

Now you are just being even more ridiculous than usual.

It seems California state authorities and Feds (mostly CA imo) way of doing things, that now the Roosters coming home to roost

I just now (2/14 AM) went back to review...

"All the water coming out of the (hole)..."

Which hole were you referring to? The only hole I was aware of on 2/10 was the collapsed bottom of the main spillway. Virtually NONE of the water going through that hole was seepage from the dam. It was all coming over the main spillway.

Anybody heard of Johnstown?

Exactly...

GA from me.

They say there is no danger, it's just the spillway that has a hole, the dam is ok. Hmmm. the spillway has a hole because of the massive amount of water overfilling the reservoir, plus more rain is on the way. Don't think I would be happy living under the tallest dam in the U.S.

slim and none

http://www.cnbc.com/2017/02/10/northern-california-tracking-to-have-wettest-year-on-record.html

http://www.sacbee.com/news/state/california/water-and-drought/article132066524.html

http://www.krcrtv.com/news/local/butte/oroville-dam-less-than-7-feet-from-the-top/324494642

5 feet??

This picture, together with prior post 13, collectively undermine Mr Guest's "piping" hypothesis. With the dam full to 5-7 feet from the top, and "piping" to the area of spillway damage, water should be gushing upward in post 14.

That sounds plausible. I was thinking similarly: a "small" leak that slowly washed out loose soil under that portion of the spillway. Some local storage areas and access roads will be affected, but the authorities on scene do not seem to be anticipating a catastrophe.

That said, this could all change if some massive rainfall filled the reservoir faster than the spillway could drain it, thus overtopping the main dam.

That "emergency spillway" is quite wide, and the top of the main dam is 25 feet higher than the level of the emergency spillway. If water ever tops that dam, much of the Sacramento valley is very soggy toast!

That is one of the (several) reasons I live at an altitude of 2100 feet!

It depends on whether the water would trickle over the top versus gush over the top. (Now we can all go and review miner's inch flow units times dam width.)

Not really. Even a trickle over the top would mean water flowing 25 feet deep out that emergency spillway. It looks to me as though that emergency spillway is hundreds of feet wide, although not all of it would be the 25 feet deep.

That much water would soon breach levees downstream, and then...

Huh? If the water is already within 5-7 feet of the dam top, then why isn't it already flowing over the emergency spillway, let alone the "normal" one? (I don't know what gates there might be at the top of either.) Of course, with incomplete, inconsistent, or otherwise dubious info, one can hardly guess.

The water was within 5-7 feet of the emergency spillway, NOT within that distance from the dam top.

The gates are at the top of the normal spillway, now seriously damaged. You can barely see them just under the word "dam" at the top left of the last image of post 1.

Go to GoogleEarth and search for "Oroville Dam, Oroville, CA". The gates are quite visible in that 2015 photo. Of course at that date, the water was nowhere close to the gates or spillway"

The spillway looks like it's in perfect condition at that time! Those are trees blocking the view of the south (right in the photo) edge of the spillway.

It's amazing the detail you can see in GoogleEarth! I measure the emergency spillway to be 890 feet wide. It's interesting to note that the GE altitude indicator shows 903 feet everywhere that water would be if the dam were full.

That makes sense, even if some earlier info in the thread was unclear.

Since there is an emergency spillway, what keeps anyone from closing the gate at the top of the damaged "normal" spillway, and simply repairing it?

Chicken-little disaster mongers, perhaps?

The damage is so extensive that it will take months to repair, and we have another storm series predicted in about a week.

They did close the gates to let those inspectors look at it. If water were to flow over that emergency spillway (it never has), it would protect the dam, but wash the entire hillside down into the Feather river.

I think they decided it was better to lose a section of the spillway than lose the whole hillside.

The way that spillway sits in a shallow trench, it looks as if water from heavy rains could get beneath and slowly undercut it, weakening its support. It's hard to tell from the photos, but it doesn't like it's reinforced with rebar or anything. Just a thin concrete shell sitting on top of soil.

Right! "it doesn't like it's reinforced with rebar or anything"

And it doesn't look like it's even a foot thick! In the photo showing the guys inspecting the hole, compare the size of the head to the concrete.

I had just moved to the area a little over a year earlier when the 1955 Yuba City flood occurred just downstream on the same river, of course well before the dam was built.

https://diva.sfsu.edu/collections/sfbatv/bundles/191491

A very large fraction of the Sacramento Valley depends entirely on those earthen levees.

PS. I live 65 miles south and a bit east of the dam (and about 1400 feet higher). I measured 4.50" of rain at my house in the 23 hrs ending at 8:30 this morning, and 13.34 inches so far in February. It's wonderful to end the drought we've been having the last 5 years, but...

Fortunately, the rain ended not long after that time, and it looks like we will have about 4 days to drain before the next storm series arrives.

Gravity causes surface water to flow down the surface of hillsides...

Ground water similarly flows downhill under the surface of hillsides...

When ground water starts to seep out of the surface of the hillsides, said water tends to carry the smallest grains of soil with it, down the surface of the hillsides...

This slight removal of topsoil starts to create a very small gap in the hillside, which no longer adequately supports the grains of soil above the gap...

More ground water flows out of the gaps enlarges them, causing more and more such erosion, as time (and water), ''flows'' on, with each such cycle...

Thus, the extent of such erosion does progress up the hillside...

This is simply how the mechanism of hydraulic piping erosion works. Period.

So? I haven't yet seen any pictures that look like that. (Though it could be happening in unseen places.)

You already have seen it, because you've seen many of the other pictures in this blog...

You just can't let yourself admit recognize it, yet...

(What does your Eight Ball say?...)

Name one--just one--picture that unequivocally shows piping erosion.

And what is that ad hominem sarcasm about 8-ball?

Look at post 46 of this thread to see the enlarged hydraulic piping conduit outlet...

Are you kidding?

And just what kind of water do you think is pouring out of the circular opening near the horizontal center of the photo, but only about quarter of the way up from the bottom of the photo?...

What circular opening? If any, it is concealed behind lots of splashing.

That little ant is a guy checking the damage.....that's a big hole....

Now it's even bigger....

Spectacular.... I wonder if any gold is being washed out?

What are those streams of water coming from the sides?

I'm almost positive those are drains from the slope that's now eroding. so rather than build up and cause a slide they drain to the chute.

I agree. In the earliest photos I saw, almost immediately after the break was discovered, I believe those flows in from the sides were visible below the break as well. Of course now the soil has been washed away below the break, so the lower drains have nothing to drain...

Gold being washed out of the pockets of Californians as they flee for their lives.

I thought the ACE was supposed to be in there repairing this? Those other streams of water are no way related to draining the rock fill under this spillway. It has another function I seem not to recall at the moment. Maybe it is supposed to keep the spillway concrete wet at all times?

Keeping it at a constant temperature to reduce thermal expansion?

That actually makes good sense.

... except that there is no such water seen flowing in the spring (GoogleEarth, 4/15) nor in the summer (Apple Maps, date recent but unknown; the dry vegetation and angle of the sun both indicate summer). The summer is when it ought to be cooled.

But P911, you bring up an excellent point. It gets VERY hot in Oroville in the summer (I've been there - got out as fast as I could), and with over 3000 feet of concrete in that spillway, there will have been considerable shrinkage since summer. I can see no evidence of any kind of expansion joints in the spillway. Of course there may be rubber seals or something like that, which are not visible in these photos, but if so, after sitting in the hot sun all summer long for nearly 50 years, any such seals would probably have lost much of their flexibility. I don't have time to do the math right now, but that shrinkage must have left significant gaps between the concrete slabs, allowing water to flow through and erode the soil from underneath the slabs.

for people that glide, you look for large cement works to get the updraft... asphalt parking lots are great.

Rubber seals for expansion joints do not last... in my opinion.

This is interesting. Seepage, leaving telltale minerals behind. (I don't know who annotated this image)

That is very interesting indeed. That could mean there is water transfer from above, through the soil, picking up mineral, then leaving it on evaporation, right?

That is the same place where the spillway failed and washed out underneath.

Very interesting indeed especially the little trucks down there inspecting the seepage they probably injected it with some siliconized caulk from home depot. Problem fixed.

Wow

By 2013 California had already experienced one year of drought, so where is this water coming from? Lots of it on the other side of that hill. Now this is just the water that's made it through the cracks. We don't know how much was actually down there nor how much it may have contributed to slope failure underneath that concrete shell when things got wetter (like heavy rain percolating through the soil underneath the drainage trenches on either side of that chute, and into the soil beneath the chute proper. Those trenches only catch runoff).

Now this pic was taken in 2013 when the area had been nice & dry and they could have core-sampled the soil beneath to estimate how much water was there. That's also on a steep part of the slope where, if it was going to happen, slope failure would be much more likely.

Don't know what the geology is there, one would need more information to answer that such as;

• The ground permeability.
• The rainfall they had received in the past 45 days
• water table? or is it an Aquifer

I repeat JS and JE's initial comments! Very interesting indeed! Now are those mineral deposits we're seeing, or is it darker because it's wet from current seepage?

The vegetation shows that the 2013 image was taken in the summer, so if we are seeing current (2013) seepage, it can only have come from the water in the reservoir. That would be extremely disturbing!

Neither the GEarth 2015 image (below) nor the Apple maps summer image show those stains, so I suspect it is indeed entrained water that somehow found its way to that location.

The cursor was very close to the center of the image when the screenshot was taken, indicating an altitude of 764 feet. That is low enough that any seepage from the reservoir could be under considerable pressure. If so, this brings the integrity of the entire structure under doubt!

I'm pretty sure I see a crack crossing the entire width of the spillway in this photo, but it does not have the same shape as the top of the break in the right-hand photo.

I'm just wondering if this pic is a bit too high up the slope. Note in #128 the road on the right is up the slope slightly from the actual collapse, but in this photo the centre of the image is above the road. Go down the slope a bit, roughly below the road and see what the chute looks like there.

ps: I'd do it myself but my Internet connection is so bad right now the connection drops before it even resolves Google Earth's host. (Welcome to 19th21st-Century central Texas ).

You mean to say your internet is as least as good as what I have here.

Yes, because he's paying the extra $5.00 premium where he can say that his is better.

Oops! You're right. I got the wrong road! Try this:

Now there are some stains visible! The light stains are definitely visible in the right-hand image of your post, just below the upper violet line. The dark stains seem to correspond to the top of the original concrete break.

The altitude is now just 574 feet, possibly adding up to another 100psi to the pressure in the subterranean water, and greatly increasing the range of possible sources, including more possibilities of naturally occurring springs.

I was really surprised to see how low the normal rainfall is for Oroville. I'm roughly 65 miles south of there, and about 1200 feet higher than the dam, so orographic lifting increases our precipitation considerably. Our normal is 39.5 inches for a weather year, and this year we've already had 62", according to my wedge rain gauges. If you look at my weather station (KCAPLACE21), you'll see that it says only 47", but I've known for a long time that its rainfall measurements were way low...

Of course the rainfall that matters here (as far as filling the reservoir is concerned) isn't the rainfall for Oroville, but the rainfall on its watershed, which is huge and much higher altitude.

I too see the crack, and that should have been seen during inspections, not ignored. It does not matter if the path of the crack at the surface matches the breakaway. That is unacceptable IMHO. Maybe they tried to mitigate this and failed? I do not know, so obviously I can point not one finger at them.

We need to go back and inspect earliest photos showing the concrete loss and undercutting of the spillway, I might lay odds we find our crack again, well not ours but the crack in the spillway.

Please avoid sensationalism! It IS a serious situation, but the dam did NOT spring a leak, and so far, at least, there is no flood due to the problem.

How prone I wonder is that dam to slope failure with all that rain soaking into it?

Isn't there a little boy around to stick his finger in the hole to stop it up?

If not, it's time for downstream people to RMFR!!

Have some fun today,

PAPADOC

its getting worse

http://www.sacbee.com/news/local/article132154774.html

I've used countless pallets of Rapid Set Mortar Mix over the years. I love/hate the stuff.

Why not drop a few thousands bags down the chute. and within the hour it will the strongest part of the damn dam spillway?

(maybe not the best method) but it would hold long enough to operate until permanent repairs can be made during the next dry season.

Doing nothing is making for extensive damage/repair/expense.

if you read one of my last entries water began going over the emergency spillway this morning, they are full and draining it as fast as they van with more water expected for days they cant patch it while 100's of tons of water are flowing

soo .. maybe too late. ?

They should have done 'it' rather than taking pictures and standing around "inspecting" and taking pictures. (Yup.. it's broked)

ahh the speed and efficiency of government.

I'll bet they inspect it and take more pictures in four days when the rain lets up.

pics if what, bedrock?

maybe pics of some very clean bedrock?..

I just saw this pic in one of your links..

uhh? I thought there was no cause for concern, but this looks like a break in a wall and not a spill down a spillway.

I also read that "engineers are not certain what caused the damage to the spillway".. really?

I was not surprised that they could already estimated repairs in the hundreds of billions.. (groan)

The wall you are looking at is the side wall of the spillway, not the dam itself.

yes.. and I meant to write millions..not billions. thanks.

But it sounded so .... Sagan-esque!

That picture is from the top looking down the spillway, and yes, both side walls of the normal spillway have fallen away by now.

"That picture is from the top looking down the spillway..."

No. look at the top right of the image. You can see the curved portion of the spillway, with the less sloped portion at the right. Also, the men are standing on the north side of the spillway. there is no similar place to stand on the south side.

The water is flowing towards the viewer, striking the uphill side of the wall below the collapsed portion.

OK then we are screwed. That is going all wash out under the emergency spillway.

Whaddaya mean going? It already did!

Hey Joe: could you go over there and inspect that ruined section of spillway next week, and please take lots of pictures. The wife wants some for her scrapbook, and her Aunt Tilda.

spillway video

https://weather.com/news/news/oroville-dam-spillway-california-hole-emergency

earlier today,Lake Oroville is completely filled for first time in 48-year history

http://www.kcra.com/article/water-begins-to-spill-over-oroville-emergency-spillway/8732032