The Lake Oroville saga continues, yesterday we wondered if the collapse of the spillway might have been due to missing or substandard REBAR, and many experts weighed it on that topic. It now appears that there was REBAR there, and the failure was likely of a nature of lack of maintenance and age combined. It appears the earth underneath the spillway was compromised, and that led to the collapse of the structure without anything to support it.
Today, it is a race against time and water, as DWR has ramped up outflow to 65,000 cubic feet per second, and in doing so, is sacrificing the damaged spillway in hopes that there will not be an uncontrolled release from the emergency spillway, something that has never happened in the history of the dam. During the super El Niño of 1997-1998, it came within 1 foot of the emergence spillway. Now, given the fact that inflow is still exceeding outflow, and emergency release looks very likely.
Here’s video from yesterday showing the damage and concrete blowing out:
Unfortunately, the last update of data at 11:00AM PST today shows a water surface elevation value of 895.84 feet, or 4.16 feet to the top at the 900 foot mark where the emergency spillway starts to kick in.
The rate of rise has slowed from yesterday, and no new additional rain is expected today, but with afternoon temperatures expected to be above freezing well above 4000 feet, we are going to see snow-meltwater continue to flow in. As of 11 AM, they were letting out 65,029 CFS, but have a staggering inflow of 132,107 CFS, more than double the release rate:
Source: https://cdec.water.ca.gov/cgi-progs/queryF?ORO
What’s more worrying is this graph comparing the 1997/98 super El Niño year to this year:
They’ve got a hockey-stick of storage going on, and much earlier in the water year than 1997/98…and they have a busted spillway.
We’ll update this story as more is known.
Here is a historical video for perspective:
https://www.youtube.com/watch?v=CF4ToIhKEeI
UPDATE1: about an hour ago, officals say they “think” they can avoid the emergency spillway:
OROVILLE
With a break in the weather and increased outflow from Oroville Dam’s heavily damaged spillway, state officials said Friday morning they no longer believe the swollen reservoir will breach the dam’s emergency spillway.
After a grim assessment late Thursday, officials announced Friday morning they think they can avoid using the dam’s emergency spillway, which they’ve been working feverishly to avoid. The emergency structure feeds into an unlined ravine, and the water would propel soil, trees and other debris into the Feather River.
The announcement came after William Croyle, director of the state Department of Water Resources, told reporters Thursday evening that water levels in Lake Oroville could reach the brim sometime Saturday, forcing activation of the emergency spillway. The emergency system, which has never been used, would dump water onto an exposed hillside, dislodging trees and earthen debris into the Feather River and potentially affect communities downstream.
Read more here: http://www.sacbee.com/news/state/california/water-and-drought/article131743014.html#storylink=cpy
UPDATE2:
As of 11PM on 2/10/17, Lake Oroville is now less than a foot from the top and overflow on to the emergency spillway.
Update 3: Oroville water level tops 900 feet, water will start flowing down spillway
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How about building Auburn Dam and a couple more large dams and not High-speed rail and more expensive renewable energy?
You don’t understand. The problem with the spillway and the high reservoir is caused by climate change. It’s wurst than the thought.
Unless global warming causes poor maintenance, uh, no.
@West, it causes everything bad, even everything wurster. If we do not act now, the children will not understand whatever happened yesterday. In this case it was rain. Tomorrow it might be sun. Who knows what it might be sunday?
All kidding aside, this is the extreme hazard presented by allocating funds to unicorn chases instead of resources that need tending.
THey have been assured for years that there would be no more rain. Thus why waste money on maintenance.
So….maybe should have spend a few $ on infrastructure instead of bankers, huh?
Who knew?
In Maine a gate failed at the Canada Falls dam and drained the lake earlier this year. It is owned by Brookfield in Canada. They are the folks buying Terraform Power and Terraform Global, which are yieldcos formed by First Wind and Sun Edison. Apparently they do not properly maintsin their real estate holdings very well…
Hell of a way to run a drought!!
are you talking about a extrawurst?
http://www.linguee.com/german-english/translation/extrawurst.html
Not global warming causing poor maintenance but the “threat of global warming“, which siphons off all funds and intellectual energy for renewables and climate mitigation so the there’s nothing left for maintenance.
ShrNfr February 10, 2017 at 11:54 am Stop being such a brat.
“Climate change” … really? What definition are you using?
Sorry to disagree, ShrNfr.
It isn’t “Climate Change” (previously known as “Global Warming”) that has caused many such problems that we face today. It is the decades long obsession with it.
Wurst? Sausages? Or do you mean “worst”?
texasjimbrock,
Doesn’t make a dfference: worst is Dutch for sausage as is the German Wurst… Oh, the nice particularities of languages…
You haven’t learned anything about history, the biggest flood was in 1860s
It’s most unfortunate that they need to overuse the Spillway due to inflow rates and not hold off until a thorough investigation can be conducted to ascertain the cause of the failure. All they are accomplishing is to Wash Away and otherwise obliderate any possible evidence
If the cause was poor maintenance, then the organization responsible is also the organization that is doing the washing away.
Must be “White Washing” the findings reoprt before the fact
How would you “maintain” some rebar filled concrete ??
I didn’t read “prestressed” in there anywhere.
Rebar filled concrete is just waiting to get bent so you can expose the iron to moisture to rust it away.
They didn’t even finish the “new” Bay Bridge before it started rotting away from rust, and when it fails they will be reminded that they were told that this was about the worst possible bridge design they could have placed in that location. The thing is holding itself up by it’s own shoe laces, and isn’t attached to anything solid that won’t move.
Well it’s kinda like the mine tailings filled bridge design.
I almost forgot. It has nice LED lighting, You need to have lights on a bridge so it makes colorful movies as it falls down in the next big earthquake.
g
Bryan A,
you mean like this?
That water downstream looks exactly like my morning cuppa
The cause is already abundantly clear. See the previous thread. “All” they’re accomplishing? You don’t know much about dams.
@george e.:
You find and seal the cracks in it (with slip or tar), and you can resurface it if needed. Find those places with subsurface soil erosion or collapse and fill with concrete. This can even be done with sinkholes. (I-4 in Orlando recently had a huge sinkhole filled that way).
The only hard bit is that you need to do this in the dry season when the spillway is unused… I.e. think ahead. Not something California goverment does well.
It looks to me like the failure was from soil erosion under the spillway then concrete collapse, not concrete collapse first. That could easily be seen and repaired if decent inspection were done.
IFF rebar failure gets bad enough, you remove and repour that section. Fairly easy on a preexisting footing in good weather. Hell to do with the soaked scoured mess they have now.
I’ll wager that the Mythbusters could fix the whole thing with Duct Tape
https://m.youtube.com/#/watch?v=FnILEXnRHP0
We can always use some of our surplus free clean green renewable non storable , use it or lose it energy, to pump more water out of the ground when we run out, next hundred year drought. That won’t happen till at least July 4 at the earliest.
You don’t really believe that California actually has a supply of grown ups, who manage the various resources of the sixth largest economy on the planet.
Maybe Elon Musk can morph the high speed rail into a high speed rail gun to lunch himself to Mars, to find us some pristine Martian H2O; excuse me there that’s “launch” not lunch !
Bitt of a guffaw there Mate
This is not even funny enough to qualify as a snafu.
This is the fourth running of the Jerry Brown Governorship cartoons.
Oh; I almost forgot; we’ll be seceding from you yanks anyhow, so we’ll just launch out into the wild black yonder.
I got a nice thank you note from the New NZ Prime Minister’s Office, so maybe it’s not too late to apologize for leaving.
Well but I really have become accustomed to this celluloid State, and its totally stupid Hollywood spokesfolks.
Even their fictition writers can’t make up stuff as good as this.
We’ll let y’alls know when to turn the lights back on again.
g
Repurpose the tubes from Musk’s Hyperloop as emergency overflow piping! There, simples! Where’s my consulting check?
“wild black yonder”
Is that a micro-aggression?
Sad to say, I have a grandson who resides in that yoyo of a state.
Why is it that so many readers here simply don’t understand that this “spillway” is not some structure sitting on solid ground.
It’s a thin film of concrete over chicken wire that is hanging up in the air.
It is NOT ….. PRESTRESSED CONCRETE …..
It has virtually zero bending strength. Just like ice, it breaks when you bend it, and you can’t glue it back together with some Elmers glue or a dash of tar .
Since the whole dam is just piled up dredging and mine tailings dirt, the material of the dam is not capable of supporting a flimsy sheet of driveway concrete.
So the entire spillway should have been built as a self supporting pre-stressed concrete rigid structure, with supports drilled down to bedrock.
It’s a total joke; well it’s also the tallest total joke in the entire United States.
G
The structure of the dam is earth-fill, and the electrical generation spillway goes under it. The two other spillways that run over the surface are on top of a natural hillside, not on top of fill. Design practice for earthen dams has always been to put emergency spillways on natural ground. If they did not have a natural area to run the emergency spillway they would have chosen a different site. If they did not have a natural surface to run the concrete spillway over the surface they would have constructed that spillway through a pipe under the fill, not on top.
While I agree with you about the fiasco that is High Speed Fail, you do realize that the Auburn Dam would have been upstream of Folsom Lake, not Lake Oroville, right?
Of course, I live in Sacramento!
Agree, agree, agree!
You are comparing the wrong water year. The 1997 flood event occurred in the 1996/1997 water year and not the 1997/1998 water year.
Cool video. Most interesting. Thanks
Nice to see the REBAR jump-the-gun speculation diminish. This event is spectacular enough without all that.
With the weather apparently clearing for a few days, it looks like they’ll avoid having to allow runoff over the secondary emergency spillway, which has no concrete but huge boulders and PGE transmission lines crossing it.
Also – at a mtn bike forum linked at the previous Oroville thread, someone posted a photo of what they claimed looked to be inspection of a crack in the spillway from 2013 (you can also see the transmission lines).
http://fcdn.mtbr.com/attachments/california-norcal/1120603d1486695238-ot-oroville-reservoir-situation-16508579_1212016275513733_1512733581637597118_n.jpg
interesting comment. Those guys are not there to test the hill-climbing capabilities of their 4x4s.
I’ll bet a FOI request will reveal this has been known about for some time.
I agree with yesterday’s post that there was NO evidence of rebar visible in the photos. I get the impression that it was bedrock and the concrete was just there as infill to provide a flat spillway, not to provide structural force. That may have been a design error.
That isn’t bedrock under the spillway or you wouldn’t see a 45 foot deep hole open up.
As long as the spillway above the current breach remains intact and doesn’t start collapsing into the hole below it should be clear sailing. If not then all bets are off.
If they choose to use the emergency spillway however they should first do an expedited and comprehensive environmental assessment first in case it may upset delta smelt habitat downstream.
The problem I had with the REBAR stuff was terms like “blatant lack of REBAR”.
Much better to just say “is there REBAR in this spillway, I don’t see any”.
The high res photo linked to from the previous thread clearly showed rebar. So did the #3 photo in the previous thread when zoomed in on. Rebar is not some rare thing invented two weeks ago. It’s standard construction, and has been for a long, long, long time. A project this size would have had immense oversight and approval at several levels. “Forgetting” or deliberately omitting the rebar would not happen in this country, and probably not in most of the world.
The chance that bedrock that long would occur right were you want a spillway is zero.
You are joking; right ??
They actually plan to run water over that ski jump !
G
It looks like they are over halfway up. So I don’t think that’s where the failure occurred.
It looks like the same spot to me. Note location in comparison to the spillway slope transition.
http://cdn.kloveair1.com/art/news/2686.jpg
External erosion is clearly visible to the right and well above (30′) the point of failure
There is groundwater leaking out of that crack. Hmmm.
As I said yesterday, piping failure. See video.
https://youtu.be/AhpMyq4ZV2k
Through rock? C’mon … you do understand where the spillway runs, right?
We have ‘potential’ for this with the earthen dam at Lk. Lewisville (north and upstream of Dallas Texas) AND it is closely monitored …
Where these four trucks are sitting is precisely where the concrete bent and cracked; probably under the weight of those four trucks. There is NOTHING underneath supporting this thing.
And Dr. Roy should be blamed for the failure because his model of the great flood said it would overflow and it did.
You are not supposed to make computer models that describe something real, because then it might show people what really is what, and they don’t like that. Dr. Spencer should have described a spillway that rotated once a day, or something like that.
Any how Roy; you won the gold medal for getting the overflow automatic engagement of the emergency spillway system correct.
Just like you said, the water went right up to the top of the dam all the way along, and then it continued on over the top, completely untouched by human hands.
People should have listened to you and then done something to stop it reaching the top.
Maybe cut a hole in the middle of the dam to let all the water out of the lake.
g
Dam questions and dam answers about a dam problem. Thanks for posting the dam video. It was full of dam information. I feel dam informed. Hopefully they find a dam solution to this dam situation with the dam spillway.
Dam right
Dam nation
Dam straight
Dam well said!
Just don’t ask 617 Squadron of the RAF to take a look at your Dam problem they will make it go away.
James Bull
The 2011 flooding in Australia is instructive. Apparently conditioned to expect continuous drought, the managers of the Wivenhoe Reservoir allowed the reservoir to fill rapidly, and only released water when they feared the dam would fail. As a result, there was much destruction and some deaths in Brisbane.
http://rogerpielkejr.blogspot.com/2011/01/large-balls.html
Later, in 2011, the U.S. had its own Wivenhoe. Despite record snow and rapidly filling reservoirs, management of the water system waited until too late to begin releasing water, and so caused unnecessary flooding.
http://rogerpielkejr.blogspot.com/2011/07/american-wivenhoe.html
It wasn’t until very late in the snowfall season in 2011 that the accumulated snowfall in the watershed of the Missouri exceeded what had been seen in numerous years before. Then the basin was treated to rainfall that accelerated the melting of the snow pack. Within a short time of realizing that snow pack had accumulated to amounts they hadn’t seen before and before the rain, the Corps began increasing the outflow from the system, and notifying those downstream that more was to come. Within 30 days of accumulation exceeding the records, the Corps was using the channel to its maximum capacity at Sioux City, just downstream from the dams that control the system.
It wasn’t that the Corps was unaware or waited too long, it was that the event occurred late in the season and exceeded the flood of 1883 that was the basis of design. The reaction time reflected the time required for the data to be accumulated and analyzed, allowing for the natural “holy $h!t are you sure” reaction. There was just too damn much water.
In that 2011 event, the Corps could not have avoided the flooding. (I was engineer for a few of the cities downstream, which is why I kept track. I did create a computer model of flows and storage to keep track.) They could have shortened the flooding but only by using reservoir flood storage capacities into the following season, which was against established policy and would have left the basin vulnerable to flooding the following season. The Corps follows policy.
To the North, we had the same issue in the Souris-Assiniboine River systems in Northern ND and Manitoba in 2011. Heavy fall rains saturated the soil, heavy snowfall built up a massive spring melt, and then heavy spring rain topped everything off. It was a perfect storm for flooding, and it was massive. Land clearing and draining didn’t help as water retention on the land was/is greatly reduced. The bottom line, however, was simply way too much water.
Chris, thanks for your take on the situation. The newspaper article Pielke, Jr. referenced had a much different slant.
The Australian situation is somewhat more complicated than that. The Wivenhoe Dam was designed as a flood mitigation dam, after the devastating 1974 floods in Brisbane. It has a rated capacity of 1,165,000 million litres (100%), but for flood mitigation, can add 1,450,000 million litres (225%).
It was to be complemented with a new dam south of the city of Brisbane intended to provide sufficient water storage for the growing population of south-east Queensland. However, construction of that new dam became a politicised issue in 1986, and no state government since has sought to build that dam. The consequence has been that the Wivenhoe Reservior now serves both purposes.
In 2011, south-east Queensland was just coming out of a 14 year drought, during which, water capacity had reduced to below 20%. While by law, water was to be released through the spillway within 7 days of reaching 100%, prior to the 2011 flood, water levels had been maintained at 109%.
As the following graphic shows, the other problem was that initial releases of water from Wivenhoe Dam did not match inflows, resulting in a massive increase in water levels, and then a massive release on 12 January which caused the flooding of Brisbane.
http://www.mdpi.com/2073-4441/3/4/1149/htm
However, after the flood damage became evident, water releases were rapidly scaled back, and the dam maintained dangerously high water levels for several days. At its peak, the capacity of the dam reached 193%, and water levels came to within 60cm of its emergency spillway. Perhaps it was just luck that no more significant rain fell in the catchment region for the next week.
Yes, Dan. As a brisbane resident I watched a similar graph go vertical showing the increasing water level on the Wivenhoe dam during that flood event. Unlike the Wivenhoe dam here, It looks like the Oroville dam doesn’t have control gates which allow water release during heavy inflows before the dam is under threat. Too bad for those downstream.
“…built in the 1960’s from clay and cobblestone recycled from an abandoned gold mine.” Yet another example of the folly of recycling. Good luck ya’ll. You’re gonna need it.
It’s not the recycled materials that have failed.
I’ll bet there will be gold nuggets downstream after all this material is displaced.
I whipped up a quick little model that estimates the hourly change in lake level based upon the difference between hourly inflow and outflow rates. By extrapolating the observed downward trend in inflow, and assume outflow remains constant, I get overflow of the emergency spillway tomorrow morning….but just barely….peaking at less that 902 ft. (It overflows above 901 ft.) So, I see why they are now saying it might not overflow. Gonna be a full reservoir though!
That’s good to hear because they seem to be awfully concerned about using the “emergency spillway” in this current emergency for some reason. Not that the main and emergency spillways being underlain by loose gravel, sand and rock nor the 770 foot high dam being composed of sand, gravel, rock tailings and clay itself could ever pose any problems since it’s global warming induced drought from here on in.
Otherwise they might want to rethink some design elements.
Hi SC,
the emergency spillway is not so much a spillway as a lower spot in the wall that will allow water to over top before the water level gets high enough to compromise the dam itself. If the water flows over the emergency spillway those flow are completely uncontrolled and there may be problems further downstream not the least of which include all the additional debris in the water flow from the emergency spillway area and including the chance to take out the 230kV lines…..
Cheers!
Joe
Joe – While what you wrote is readily apparent now, I asked a similar question before it was so apparent and did not really get a good explanation. Yours was what I was looking for. I appreciate the explanation. The reason for the scrambling to avoid using the Emergency “Spillway” is very easily seen now.
Hi Joe,
Just thinking that as long as the main spillway does not start collapsing upwards of the breech that they may wish to open the main spillway gates further since it is rated for a 250,000 cu feet second discharge capacity. There is going to be one heck of a lot of sediment washed downstream in any event.
https://en.wikipedia.org/wiki/Oroville_Dam
re: “they seem to be awfully concerned about using the “emergency spillway””
Yeah, as Joe points out it (the “emergency spillway”) simply prevents water from OVER-TOPPING the DAM which WOULD be catastrophic …
I see hockey sticks floating on your reservoir model.
Hey Roy,
.
Could I get those inflow numbers you used? I see the last single rain event raised the water from 848 to 901 in five days…. I’m trying to extrapolate the NEXT rain event looks like Thursday – Wed. If the dam only draws down to 860…. well. 910 will crush the ailing emergency weir in a few hours.
The damaged spillway seems to be defeating the avoidance of the Emergency Spillway. Might as well use the emergency one as the regular one will need to be rebuilt once the crises is over.
I think they are avoiding the emergency spillway at all costs because of the massive amount of erosion it will cause…they’d rather use the damaged concrete one. Gonna be a big hole left though, and the snowmelt hasn’t really gotten going yet.
They can modulate the damaged one, the emergency spillway is uncontrolled. Usually the emergency spillway is less protected from erosion. They are likely sacrificing the structure of the principal spillway for control, knowing more than we do about the underlying geology.
Hopefully the downstream salmon are wearing goggles….
I don’t think the “emergency spillway” can be regulated in any way. Its better termed as emergency overflow, and configured only so as to not damage the dam itself.
Letting the water pile up to the emergency overflow level does not leave any ability to further manage outfall rates. IN = OUT; nature in complete control.
The 1953 Tangiwai disaster in NZ happened just after midnight on Christmas eve.
A giant ice dam collapsed on the glacier blocking the crater lake on Mt Ruapehu from exiting all at once down the Whangaehu river. The avalanche of ice and mud and volcanic boulders and trees all hit the railway bridge at Tangiwai , just as the midnight express from Wellington to Auckland was crossing the bridge.
The whole train and brideg, went in the river carrying almost 400 people to their deaths. Those who were found were full of glacial river silt. Most were never found.
It happened during a Royal Visit by the new QE-II, which really put a damper on things. They packed up the Royal Yacht and set off back home.
Turning a lot of water loose in a boulder filled gulley upstream of a river like the Feather river, is not going to create a lot of friends in the area.
Only in Dubai can you build your house on sand and get away with it. But I don’t think those clever Arab architects are using oil well drilling tailings to built their structural monsters.
Hopefully, Dubai is not a good location for free clean green renewable wind energy.
G
I don’t think the emergency spillway is controlled (I may be wrong). I think it’s a designed depression at the edge of the highwater level of the lake, so that if the lake surface gets to a certain level, that’s the spot it will overflow.
I understand that now. Thanks. I am learning a lot about Dams, and this one in particular.
A similar event happened in 2002 at a central Texas flood control reservoir. Canyon Lake had been impounded in the early 1960s and never used the emergency spillway . The spillway was concrete lipped but the rest was a natural saddle draining back to the riverbed after several miles.
The flood of 2002 caused a rise to spillway elevation plus 7 feet. The 300 yard width of the spillway was designed to limit downstream flooding but the erosion products deposited in the river bed made floodgate operation impossible so all control was lost.
The same will happen here.
The destroyed spillway is allowing plenty of erosion products to be gouged up. The river below is becoming so muddy that the salmon are endangered. If / when they have to use the emergency spillway the problem will be much worse. link
I wonder how much erosion/muddy water (and salmon harm) there would be if the full 135K cfs were passing the location of the dam. 🙂
And in the summer (without the dam), with some years of low to no flow …. historically, how did the salmon cope?
Dams are good.
They’ve been sucking up baby salmon at the downstream hatchery and hauling them away in tanker trucks to different locations for the past couple days.
Remember, the damaged spillway is caused by Trump & right-wingers. If only they had stopped using fossil fuels, it would never have happened….
/sarc for the clueless
I sarcend that comment.
Just don’t sarc-rifice that comment.
Sarc-hasm…
It was during the huge rain of 1996/97 that Oroville Dam was almost over topped, not the winter of 1997/98. The winter of 1996/97 saw massive rains in Northern California, and in the winter after that was when Southern California received very heavy rains. I remember distinctly as it was a point of change in my life’s circumstances.
Stories related to the 1996/97 flood. …http://www.cnrfc.noaa.gov/storm_summaries/jan1997storms.php
and, …http://www.wrcc.dri.edu/extreme-events/california/#1997 New Year’s Flood
This is a cool video on the use of the emergency spillway at the San Pedro Reservoir in California in January 1997.
Thanks Quinn. Interesting and informative vid. At the 26.30 mark ( and on) they showed a scoured out section of twin Gulch all the way back down to bare rock.( and other areas) I wonder if in their infinite wisdom they filled it back in so that with today’s excess of rain they’ have trees gravel and mud clog up down stream areas?
The make speaker has an amazing voice.
I want to rub that voice all over me.
We’er all goinna die! Aaaghhh
You’re all wet. On the other hand, if I’m wrong, you’re still all wet!
It’s hard to avoid death. Just saying …
given the current rate of decay for the human body, would you really want to live for more than 120 years
They say the first person to live to 150, besides Methusalah, only has less than 100 years left.
And the first person to live to 1,000 has already been born.
I’m outa here before that.
g
By the time you get to 1000, immortality is just around the corner.
I calculated once how long it would take the human body to soak up a fatal dose of radiation from just the background, given that dosages are cumulative over one’s lifetime. I think the answer was around 1200 years, certainly less than 2000.
Your given, isn’t.
The body repairs damage as it occurs. So long as the rate of damage from the radiation does not exceed the bodies rate of repair, there is little problem.
The odd thing is how the spillway initially failed. It collapsed. There has to have been underlying structural support damage that went undetected/unrepaired. Simple cracking of the concrete slab would not matter because of the rebar. Only if the earth underneath the crack had significantly washed out would you get the apparent initial collapse. That is something readily detected by simple visual inspection, I would have thought. Now the turbulence will rip out everything below the initial failure, down to bedrock.
and any evidence will be washed away
No spillway on God’s green earth could have stood up to that torrent of water. And who says the emergency release will hold up. I really fear for those down below. Don’t mess with Mother Nature. We are just ants going about our business.
re: “And who says the emergency release will hold up.”
Once the top soil (what little there is on a hill made of rock) is gone, what’s left will be ROCK. The problem is the ‘debris’ (trees and dirt) washed down into the river below as I understand it …
Please, correct me if I am wrong.
I would have thought it would be stripped back to bedrock before being filled with concrete. I would not want to rely on the structure integrity of earthfill under a spillway below a dam !
THEY did (see response below to George.)
Well you are supposed to clean out down to the bed rock before you start building; not after you have built your dam.
g
re: “clean out down to the bed rock”
THEY did (FOR the dam itself). Go watch the documentary (at the end of the other, initial, thread) …
Exactly right. The clean “break” at the upper end of the failure suggest it is a construction joint. It appears the lower slab fell into an eroded cavity, perhaps initiated by water seeping in though the construction joint and/or the sides of the pour. The concrete does not appear to be structural, but a “slab on ground” skin to protect the underlying base – likely compacted rock, from erosion. Just guessin’ tho
BTW – OT if you’re reading about monster heat waves down here, no State capital is forecast to get any where near 40C in the coming week, most mid 20s – low 30s. Sure it’s hot inland but hey deserts get that way.
Since it’s not renewable energy, why don’t we stop filling the dam.
There is a generator in the dam, providing energy, likely now running at max capacity. It provides part of the outflow so that less goes over this structure. The outflow from the damaged spillway can be modulated, the outflow from the emergency spillway cannot. They are doing their best to avoid filling the reservoir and avoid causing flooding downstream. There’s too much water.
Sorry, I was being sarcastic. The current refusal to categorize hydro as renewable annoys me to no end.
Debris in river backed up water to generator outlets so they are off now. Loss of 15000 acre feet hr and 860MWH
There should be some great recreational gold mining this coming summer in gold country.
Possibly even some good Recreational Vehicle mining
OK, that’s just plain funny.
If this dam were to ever fail, then there would be a gold rush on the Feather River drainage such as hasn’t been seen for 130 years. In 1981 I dredged the Middle Fork Feather River and averaged close to 3 pennyweight per day. Seven years later I dredged the same spot just to gain understanding of how the river might replenish the gold. In 1988 I also averaged 3 pennyweight per day. I would love to get back in the river as I could supplement my SS for the year by dredging. I would no longer need foodstamps. I would have never filed for foodstamps, if dredging had not been made illegal.
Dredging the lake would extend the life of the dam.
Therefore it would be opposed by the Green Machine.
I think it is a bit too late to talk of dam failure; This one has already failed.
Now they have to figure out how to get rid of all the remaining water and the mine tailings and get down to bed rock so they can built an adult dam instead of a toy one.
G
The dam is undamaged. It’s the spillway that has problems.
That would be quite a project. On another note, next winter could well bring the main event of an even bigger series of storms than seen in this winter. It is hard to say at this point in time if this is the solar related cyclic flood pattern. The winters on either side of a PNW cyclic flood are also strong rainy winters. So this rain could be the runner up to the cyclic flood, or it could be the main event. If it is the main event, then I now have a clue as to when the next solar minimum will take place as well as knowing what winter the next cyclic flood will take place in.
If the dam failed Oroville would be wiped out. It’s the spillway that’s had the structural failure.
Without the spillway the dam is already damaged.
If the spillway really isn’t needed why did they build it to begin with ??
G
The dam has not failed! Quit scaring people. If the dam were to go, it would take out all the communities in the lower Sacramento Valley including the state capitol Sacramento. About a million lives would be lost in case of a sudden, unexpected collapse.
george e. smith February 10, 2017 at 1:45 pm” “I think it is a bit too late to talk of dam failure; This one has already failed.”
It seems to this engineer (although not a hydrologist) that ‘things’ are operating within spec, save for a wide ribbon of concrete that acts to duct ‘spillway’ water down a hill. AND, I suspect there is a helluva lot of ‘rock’ beneath the ‘thin’ veneer of soil on the hill (NOT the dam) down which the concrete ribbon runs.
“If the dam were to go, it would take out all the communities in the lower Sacramento Valley including the state capitol Sacramento.”
So let’s hope it’s earthquake proof when it is on maximum capacity.
Nothing is earthquake proof. However it was designed to survive a normal sized one. If an 8.5 or higher one hits, all bets are off.
Hmmm, seems like climate modelling has exactly the same utility as economics in predicting, preparing for and avoiding catastrophic events- which is to say zero. Maybe it is wrong to blame it on climate modelling though. No climate modelling was needed to identify that New Orleans was at risk and still nothing was done. Ah ha, the real reason for CAGW, it is irreplaceable as a scapegoat for all administrative bungling. No wonder governments support it!
Well, at least no Climate Models were harmed by the breaking of the Spillway
This has nothing to do with climate modelling. The design was based on either the largest event known to have occurred, (as was done for the Missouri) or a statistical analysis of prior rainfall data.
It was climate modeling that claimed that drought was a permanent feature of CA now. It could have led to a reluctance on the part of the operators to start releasing water earlier.
re: “This has nothing to do with climate modelling:
BUT – was maintenance deferred b/c ‘models’ showed rainfall would never ever be an issue again?
Just asking the question in light of what we may seem to know at this point …
Well it’s a lot easier to know you are up a creek when you are already under water.
Those French geniuses were really on to something in N’orllns.
I think they are the same folks that have already poured all of the concrete for ITER.
It’s a new approach to product design. First we’ll build a nice box to ship it in, and then we will see if we can make something to go inside the box; something useful like a fission power plant.
g
The French Quarter is fine. It’s the rest of N’awlins that is sinking.
135k cfs in. 65k cfs out. Effective 70 cfs detained.
Imagine what the downstream river would have looked like @ur momisugly 130 cfs w/o the dam. Dams are good.
…130K cfs
With water quality being the latest environmental sin that threatens those working in the private sector, it will be interesting to see what the state’s water quality control board will say about another state agency’s MAJOR violation. There will be significant erosion of the native ground under the spillway. And before this is done there will be additional structural damage done to the concrete spillway chute. This will be a major black eye for DWR especially if it is established that the spillway was not adequately inspected when was last scheduled.
Well it obviously wasn’t properly inspected, while it was still on paper in a dam architect’s office.
G
Other factors you don’t consider are 1) workmanship and 2) age-related issues (e.g. erosion). Also, materials selection can be out the architectonics’s hands too.
There has been a lot of seismic activity under and around Oroville Dam since it was built because of the weight of the water it contains and also from the pressure forcing water into faults near it. It wouldn’t surprise me that the damage was caused by some unknown stress fractures in the spillway or from weaknesses in the ground supporting it because of past seismic activity.
http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&ved=0ahUKEwj50dbk_YjSAhUT9GMKHQyoAAAQFgglMAA&url=http%3A%2F%2Fwww.johnmartin.com%2Fearthquakes%2Feqpapers%2F00000052.htm&usg=AFQjCNFXZ8nR9ZEg8fiOFCv_rzrcUcddGg&sig2=feY7_7vTt3HfksPsx4IOkA
http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=2&ved=0ahUKEwj50dbk_YjSAhUT9GMKHQyoAAAQFgguMAE&url=http%3A%2F%2Fwww.sacbee.com%2Fnews%2Flocal%2Fenvironment%2Farticle2584322.html&usg=AFQjCNHed0SEYB-K2rMizANic2klsj6Gng&sig2=ZnPu1KsRjcnzSH5ogVYOMg
There are many reservoirs in Northern California, Shasta on the Sacramento River and Oroville on the Feather River, being the two biggest. Would California be in a scenario similar to the flood of 1862 without the reservoirs impounding massive amounts of runoff this year?
Excellent point. The original purpose of most dams was flood control. Water storage and energy generation are secondary purposes, which have now been elevated in importance – often meaning that the flood control aspect is now overlooked (see references above to Australia and US floods).
There was erosion damage to the base that caused the failure. How it happened is a matter for investigation, there are several routes that could have cascaded into that erosion damage to the base. Rebar in the slab is very unlikely to have affected any of those routes. The joints between the panels would have given way before the slabs cracked either with or without rebar.
Looks like the CA perma drought is coming along swimmingly.
@ur momisugly resistance , to me it’s being hung out to dry.
I was stationed downstream of the Conowingo Dam during hurricane Agnes in 1972 when, all 53 floodgates were opened and explosives planted to blow a section of the wier and the Teton Dam in 1976 when it failed.
Nature can be very humbling.
Heh, that’s funny. I must have followed you at that time, although at a much younger age. My dad grew up in Wilkes-Barre, PA (not Conowingo, but farther up the same river) and we used to go on vacation there every year to see has family (my grandparents, uncles, aunts and cousins), and we drove through Wilkes-Barre after the Agnes flood. In 1976, when I was a little older, (1976 0r 1977, can’t remember which year now), I went out west on vacation with some friends and we went by the Teton Dam. Also went through Big Thompson canyon in 1977, after the big flood in 1976.
My first commercial nuke was the startup of Susquehanna Steam Electric Station. The plant was built above US 12 rather than the initial location closer to the river because of the flood.
Years later I took a Environmental Geology Class that used this event to explain how we change things like 100 year floods by paving natural runoff. After I shared my personal experience for the first three case studies, I was asked to move to another state.
Considering the level of environmental ignorance in CA, I would not remotely be surprised of the environmental extremist crowd has been fighting any repairs or improvements of the dam. That is what they do.