As the saying goes, when it rains, it pours.
Over the last week, Murphy’s Law has been on overdrive in Northern California as Oroville dam suffered a series of mishaps, resulting from poor planning, lack of maintenance, and lack of heeding warnings years ago on the part of the state bureaucracy known as the California Department of Water Resources. The result was a badly broken regular spillway, a damaged “emergency spillway” (if you could even call it that, since they had to do emergency prep for two days to even make it usable) and finally, a several county evacuation downstream of about 180,000 people because DWR officials feared the “emergency spillway” would breach.
Given the attention paid to this worldwide, in technical parlance, it would be safe to say the DWR made a global cluster f*** out of their mismanagement of the dam. Even the White House got involved, calling the mess DWR created a “textbook example of the need for spending“.
Our local newspaper, the Enterprise Record, had a scathing editorial using less colorful wording than I have, calling it a “failure on many levels”. And, the Feds aren’t happy, and have sent them a letter demanding some immediate accountability by an independent review, something DWR isn’t used to, since they have a history of being accountable to nobody but themselves.
For example, the re-licensing process for the dam; it was started on 2002, and to be completed by 2007 but has dragged on for 15 years! It only took seven years to build the dam:
Construction was initiated in 1961, and despite numerous difficulties encountered during its construction, including multiple floods and a major train wreck on the rail line used to transport materials to the dam site, the embankment was topped out in 1967 and the entire project was ready for use in 1968.
Combined with the mismanagement under our current weather situation, it’s fair to say that DWR’s oversight of Oroville Dam is a complete and utter failure. Maintenance was deferred, warnings weren’t heeded, and there was a mindset of global warming induced “permanent drought” out of Sacramento. New dams, such as the Sites Reservoir aren’t being built, being stalled in funding, despite a doubling of Califonia’s population since 1968, and monetary focus has been on Gov. Jerry Brown’s pet boondoggles such as “Bullet Trains to Nowhere” and “Water tunnels under the Delta“. Ironically, the tunnels would rely on water from Lake Oroville, which seems to have gotten lost in political space.
People with an ounce of sense proposed killing the bullet train, and putting money towards water storage, but, sadly, it didn’t make it past the rancid political interests of Sacramento and Brown.
All of this has combined to nominate DWR is a poster child for everything that is wrong with California’s government.
So, with that in mind, we have a new challenge from mother Nature ahead: A series of 5 storms over a weeklong period that could give up to 8″ (or more) of rain in the Oroville watershed area. On the short term, NWS is forecasting the storm on Thursday could produce up to 1 to 2 inches of rain in the foothills, with more at higher elevations.
The long-term forecast has rainfall totals withing the watershed that are showing the exact spot where Lake Oroville watershed is located will get 11.62 inches of rain over the next 10 days, the most accumulated rainfall in the entire western USA:
From today’s ChicoER article, there is this quote from DWR:
In a press conference Tuesday, Department of Water Resourecs acting Director Bill Croyle said that there is room in Lake Oroville for upcoming storms and that the inflow was not expected to reach 100,000 cfs.
Given that DWR said 11 years ago that the spillway was safe in response to challenges, then last week they didn’t think there would be any problems with the storms, then kept slipping into disaster mode inch by inch, walking back all the way to “The emergency spillway might fail, therefore evacuations are needed” why should anybody believe one word these bureau-clowns utter?
I sure don’t.
UPDATE: About a half hour after publication, the missing word “spillway” was added to the headline for clarification. The dam itself is not damaged, but the dam spillway is.
Before any Federal emergency money goes to repair of this dam, we need to know how much revenue it has generated for the State of California and why some of that revenue stream has NOT gone to maintenance and upgrades.
The Lamestream media is already blaming Trump who had nothing to do with any of this and are demanding all taxpayers pay for repairs even though they all boasted just last week that California ‘was the richest state’ and voted against Trump.
I say, let them swim.
With a history of stunning incompetence in Sacramento, about the only corrective action one might expect from them would be to shift the blame from Trump, back to Bush.
I’m ever so glad that Chico is above the dam.
emsnews February 15, 2017 at 11:56 am
“I say, let them swim.”
I say no federal money for a sanctuary state. This will be great practice in self-sufficiency for after Calexit.
I’d like to agree, but I didn’t vote for Guv Moonbeam and am too old to swim far! That said, Caleeforneea has plenty of money to burn on stupid projects and government handouts to people who came here illegally.
Hopefully they can’t.
Yes, if the Fed’s can do nothing more to physically help, then why enable the petulant state with money?
( I live here btw)
https://goo.gl/images/UnL5Ho
The Cal. Water Resources Board should be required to ‘show cause’ why they are competent to continue managing the dam. The penalty for not being able to do so should be requiring the sale of the dam and its operation to a private utility charged to make a profit from the safe operation of the resource. Deferred maintenance my a***!
At this time, my thoughts are with the engineers who is trying to control this mess and avert a dangerous and costly disaster, and with the workers at the dam site trying to control the erosion under difficult and dangerous conditions. These guys probably did not make any of the mistakes that led to this situation, they may not have adequate authority or resources to do their jobs, and are probably facing interference (aka “help”) from know-nothing politicians and others.
All the finger-pointing and background noise is a distraction to the main event. The important question now is do the guys on the ground have the authority and resources to control the problem.
Been there, done that, and all the finger-pointing, background noise and “help” is a distraction they do not need at this time.
Good luck, gentlemen (and ladies). Focus on safety. Let’s be careful out there.
Best, Allan MacRae, P.Eng.
Here are my earlier comments on the Oroville Dam remediation.
https://wattsupwiththat.com/2017/02/12/oroville-dam-spillway-expected-to-collapse/comment-page-1/#comment-2425550
In other news, this was announced yesterday – another potential disaster averted (aka “How I spent my summer vacation”).
ALBERTA SHUTS DOWN LEXIN RESOURCES, LEAVING BIG MESS TO CLEAN UP
‘You don’t see these very often,’ says Alberta Energy Regulator in largest shutdown ever
http://www.cbc.ca/news/canada/calgary/lexin-resources-shut-down-1.3984287
Allan M.R. MacRae
February 16, 2017 at 2:43 am wrote:
In other news, this was announced yesterday – another potential disaster averted (aka “How I spent my summer vacation”).
ALBERTA SHUTS DOWN LEXIN RESOURCES, LEAVING BIG MESS TO CLEAN UP
I miss the Southern foothills of Alberta, but not so much the sour gas wells and the web of pipelines.
I’ve frequently been amazed how oblivious even technical professionals can be of the presence and potential hazards of life surrounded by sour gas wells.
You can’t miss the flaring stacks driving into or out of Calgary after dark, and a hazardous materials officer with the city fire department once told me that it was ” every man for himself” if ever a major sour gas leak occurred near the city core – there was no emergency plan. “Run up to the 17th floor or higher if you’re downtown” was his advice.
That was many years ago, but I’ve noticed, from afar, that the zoning for gas plants and wells with respect to residential areas has become ever less restrictive.
I looked at the orphanwells.ca site, but was disappointed to find no maps. Are there any publicly accessible websites showing maps of sour gas wells, pipelines and/or plants in Southern Alberta?
otropogo – there are maps on the net, but they are not that easy to find.
The dangerous critical sour gas wells that were shut in were about 1 mile from the suburbs of east Calgary, and a big leak with an easterly wind would have killed thousands or tens of thousands, imo.
The City has encroached upon the wells over time, as successive City Councils approved subdivisions closer and closer to the wells.
I understand the “emergency plan” is for the fire dept. to ignite a sour gas well that is close to a community – but how many people would die before the well is ignited? There will be no time to evacuate with an east wind.
Sorry I cannot be of more help.
otropogo – here is one map of Calgary wells – your thoughts?.
https://calgaryrealestatereview.com/2012/01/12/sweet-oil-sour-gas-wells-locations-in-calgary/
No it’s broke, and they don’t have the money to fix it. Well the had the money but they pissed it away down rat holes.
Excuse my accent there; that just seemed to be the lowest energy response I could come up with.
G
Moim zdaniem jebnie!
When does the melt start at that latitude and altitude?
The melt can vary quite a bit depending on changes in the surface winds. During the drought years it has been quite warm early on in the year. Two years ago at this time the Trinity Alps had zero snow on them. Those peaks range as high as 8,000+ feet. That was actually unprecedented. The pendulum has swung back though. This year the mountains around here have snow down to around 3500 feet. The spring runoff will be heavy, especially if the rains continue through March and perhaps through April. I like watching nature roar.
It was an el Nino winter. ‘Unprecedented’ means ‘since recent people came to California. California and Arizona both had epic droughts lasting more than 50 years at a time, terrible droughts, during the last 3,000 years.
goldminor,
“I like watching nature roar.”
So do I.
From a safe distance. Web-cams and such.
No, not /sarc at all.
Nature can roar. And ROAR. Do look at Tangshan, for example; the 1976 earthquake killed – uhhh – lots. Maybe 700,000. Less or more.
Shedloads.
Auto, in the UK, where, happily, we get fewer of Natures roars. And almost none of her ROARS . . .
Storegga Slide – yes, but thousands of years ago.
In the 1970s I lived next to the Klamath River. Standing close to the river was an experience. You could barely hear your own thoughts, so to speak. To talk to someone standing next to you would require shouting in their ear to be heard. In the meantime the ground around you would shake from the movement of boulders crashing down that very large river.
I remember the roar during the Loma Prieta Quake. That was also impressive, and the biggest quake I ever directly experienced.
I remember “The Mouse That Roared”.
“I like watching nature roar.”
I’ve stood next to a set of rapids in the gorge of the Upper Colorado during the spring melt, and that is truly an awesome sight. Standing waves the size of 2 story houses in that torrent, and holes behind them to match.
Billions wasted on Wind Pork…
Fill the great crevasse with windmills and solar panels…
A foot of rain…. that will be a disaster… sad..
Anyone living in the flood zone should pack up as much as they can and find a new place to live.
If the next set of storms doesn’t cause the dam to fail, then the 175% of average snowpack will do it, when it melts in a few weeks. Maybe, just maybe, they’ll come up with a miracle fix to one of the spillways. But, what then? The erosion has already occurred and it might be a very wet spring for the region. It would seem, that at this point, it isn’t IF the dam will fail, but WHEN the dam will fail.
Main spillway stable last four days . Lake level lowering . Emergency spillway being repaired .
Why should we expect failure ?
How is the main spillway stable when it has a huge hole in it eroding the base of the dam?
How is the emergency spillway going to be repaired by dropping rocks into the holes caused by the water release erosion?
Yes. What could possibly go wrong?
I do backhoe work in the mountains. The puny pile of rocks on a huge hillside that has been scoured of all dirt are like billiard balls: they will roll the minute anything hits them like say, water.
These ‘repairs’ are useless. Millions of tons of dirt has to be brought in and packed down very hard to repair this mess. It will not be cheap nor easy or fast and you can’t do a thing when it is too wet.
Logan . Suggest you check Metabunk site , Large amount of info .
Main spillway not eroding at any significant rate , if any . And it’s discharge is hundreds of feet away from the base of the dam . Lots of money required to restore it ….that is the worry , not imminent failure .
Thanks Sweet old bob. The hysteria is amazing, as you said the MAIN spillway broke part way up the chute and way lower than the actual dam. after days of releasing water the outflow has now scoured it’s water track down to bedrock ( which should have been done years ago instead of a “pretty” chute. the 1700 foot long emergency spillway worked. The problem was the added parking lot structure years afterwards that allowed water around the emergency spillway.
Had any thoughts about the detritus build-up at the end of the destroyed area of the main spillway? Blocking the spillway at the end could mean the water just has nowhere to go but up. And we know where that ends.
The “Emergency spillway” is not some entity capable of being “Repaired”.
For “emergency spillway”, read: “It’s the top of the dirt dam.”
It works by residing at an altitude that is LOWER than the altitude of the lake water surface.
At that point the lake water is free to exit from the lake by any means it chooses.
You can’t “repair” stupid !
G
And the main spillway is busted; it doesn’t work properly now.
Bob, you are kinda whack here. The last 2.5 ft over the emergency spillway produced major erosion, some moving back quite close the the emergency spillway wall. Additionally, there is a weak area beyond the emergency spillway to the parking lot. It was already failing from the last episode. The ONLY thing you need to track is the forecast for rainfall, then we will know.
https://www.youtube.com/watch?v=CgBW09wd5so good pics in this video, take your choice whether you believe what the guy is saying.
If they make it through the spring, then they can make repairs before next winter. The danger of warm, heavy rainfall in the coming months is the main worry.
What comes in spring? Massive snow melt. The planning for all this was crazy. They deliberately let the catchment water rise nearly to the top because ‘global warming means no water’. So they wanted to hoard the water.
Then it overtopped the emergency dam. This was all about human stupidity, not nature. California has this typical cycle all the time, anyone there for the last 150 years knows this.
We know that. Unfortunately, the lefties running this state have no clue about the history of the state, or so it would seem. I can’t think of a greater irony then Oroville dam being threatened under the watch of Jerry Brown, as this dam was built under the governorship of his father.
ems, beyond that, years of believing that drought was permanent allowed them to justify skipping on basic maintenance of the spillway. After all they had trains to nowhere to fund.
As a result when they realized the mistake they made this year and opened up the spillway, part of it collapsed.
As we have seen over the last few days, they could have continued to allow water to drain over the spillway at a much higher rate, but they didn’t for fear that erosion would pollute the river downstream. The result of this caution was the height of the water behind the dam is now much higher than it would have been had they been more aggressive in releasing water in the early phases of this disaster.
Speaking of erosion, have you noticed the muck in the water between the damaged spillway and the face of the dam? Silt will steadily deposit there until this is resolved. They will have some cleanup to perform before they can use those turbines again.
Why won’t the turbine outflow just scour all the dirt away from the base of the dam?
It oughta be coming out of there pretty forcefully, no?
@Menicholas; “Why won’t the turbine outflow just scour all the dirt away from the base of the dam?
It oughta be coming out of there pretty forcefully, no?”
The problem for the turbines is the accumulated debris at the intakes of the turbines is not at the bottom . As the lake filled and water was spilled, debris floating on top of the lake was starting to go down the intakes of the turbines (the intakes are at the lake level not the exit level of the turbines) They had to shut down the turbines before they sucked in debris from the top of the lake.
Historically, the snow continues to melt into June. We rely on that. This year is considerable colder than last year, and the snow may last longer. Calculations are that at the current rate of release, the dam will survive.
That said, I’m glad I don’t live in Oroville, I AM sad I still live in Kalifornia, the land of Moonbeam and Hollywood, where emoting is substituted for reason.
Calculations made by the people who said they would not need to use the emergency spillway until they suddenly needed to use it, the same people who said there was no danger until they told hundreds of thousands to evacuate in one hour?
The same people who did nothing when warned that the spillway needed to be repaired?
And that let a small hole grow to a huge gash and then to a gigantic scour at the base?
They should have turn off the flow to the spillway and let the emergency spillway take the flow and called every concrete contractor in the western US to hurry in and get to work.
They multiplied their problem every step of the way.
And last time I checked, calculations of rainfall rates and amounts more than a few days out are uncertain.
Some places will get less than expected, some places more, and a few will get much more than expected.
And who knows what is coming next week, next month…April…?
I would not bet a nickel on those jackasses getting anything right, or even on them getting lucky.
Menicholas. feb 15 2017 6. 14 pm.
“They should have turn off the flow to the spillway and let the emergency spillway take the flow and called every concrete contractor in the western US to hurry in and get to work. western US to hurry in and get to work”
Please That part of the MAIN spillway broke but it had no effect on the dam at all..
Using the emergency spillway to release over 100,000cfs would have turned into the disaster that was completely avoided. By opening the “broken” MAIN spillway and let out up to 100.000 cfs contained the problem. If the “emergency” spillway would have had to let 100,000 cfs go over the top it would have been obliterated. It was only designed to let a +/- 12,000 cfs go over. The problem was the parking lot.
asybot, all correct except the E.S. was suposedly designed to take 250K CFS. Instead it was almost done in by less then 5 percent of that.
Sweet Old … (Can I just call him Bob?) Bob is right. For three days and nights that hillside has been scoured by 100,000 cfps of water. Think of a fire hose blasting negroes off the street in Alabama. Now imagine that fire hose were wider than Interstate 5. That’s whats been blasting the dust off the bedrock at the base of the Oroville spillway. There’s no loose dirt or gravel left to erode.
There was precious little to begin with. Just the stuff that’s built up since the days of hydraulic mining.
The only thing left is the stub end of the spillway itself.
The lake level is 30 feet below full, 871.93
http://cdec.water.ca.gov/cgi-progs/queryF?s=ORO&d=16-Feb-2017+01:15&span=12hours
That’s a nice big soaking storm there but there is just no way it’s going to fill up Lake Oroville with the spillway open.
@ worrry about the levees along the Feather and Sacramento rivers if you want to worry about something.
Except that the rock is not what they expected it to be in the first place. So, while the erosion has slowed, it has not stopped. There could be a point where the erosion takes out a chunk lower down, that ends up taking out a chunk higher up. Or, possibly the rest of the spillway fails, since it was doing that without water.
I’m not worrying, because I’m not there. I just don’t think they are being completely honest. They thought the emergency spillway could handle much more water, but found out quickly it could not.
“Sweet Old … (Can I just call him Bob?) Bob is right. For three days and nights that hillside has been scoured by 100,000 cfps of water. Think of a fire hose blasting negroes off the street in Alabama.”
A super sized hydraulic mining jet.
I’m not worrying, because I’m not there. I just don’t think they are being completely honest. They thought the emergency spillway could handle much more water, but found out quickly it could not.
Well actually there’s a lot of hill backing up that emergency spillway on the lake side that was hidden from view by the water, but I think you’re dead on target that the state isn’t being honest with what’s going on here.
The more I look at it the more it seems like battle space prep to ram though the peripheral canal.
Anthony,
I could not agree more. There was no need to run water over the “emergency” spillway as the increase in flows over the damaged main spillway was clearly not going to cause any more problems than increased erosion primarily down the slope. You can see the large rock formations to the right of the damaged spillway and that was good evidence the serious erosion would be contained. The increased releases and the results have proven that. I have little use for DWR and their arrogance generally exceeds their competance.
The flow from the damaged spillway turned clear yesterday afternoon. Means no more erosion. Upstream the break seems to be holding. Now they have to clear the diversion channel between the spillway and the power station. That work started yesterday. Big backhoes and barges being positioned. Once the debris bar is cleared, then they can use the powerstation penstock to remove water at ~ 14,000cfs and cut down flow on the damaged spillway. Problem is time with more rain on the way. To a rough cut, 1″ means 12.5 feet in the reservoir (depends much on snow/rain mix). They want a 50 foot lake level margin. At current 100kcfs they are lowering 8 feet/day and are down about 16-20 feet. So need 4 more days. And would loose it all with just 4more inches of rain.
My understanding, and correct me if I’m wrong, was that the water went over the emergency spillway because everything else was wide open and the lake level was still rising.
wws partly right. The main spillway was used to relieve at a rate of +/- 100,000 cfs. The penstocks could have released another 12,000 cfs but were shut down because of a debris problem. The main spillway was designed to go up to 150,000 cfs but was never used at that level, and you are right eventually the 1700 ft long emergency spillway had to start, and btw NOBODY can control that spillway , no gates , shut off valves etc it is just a levee when the water goes over, ? guess what, it goes over and you can just watch!
wws and asybot: The main spillway was not wide open. It was spilling about 60,000 cfs and the lake level was slowly rising. At that discharge rate the water eventually topped the emergency spillway and they let it run, probably to see what would happen, i.e., whether it could be relied upon. When the area by the parking lot started to seriously erode the towns below were put under mandatory evacuation with the fear that the emergency spillway could fail in an hour.
At that point they ramped up the main spillway to 100,000 cfs or so and then, from the dam records, once the level dropped below the emergency spillway they stopped the main spillway discharge completely at two different times, probably to check for damages at the higher discharge rate. They then resumed the 100,000 cfs rate.
I would guess that they could even increase the main spillway rate above that now if they need to, and it appears they might need to at some point. But until the problem with the emergency spillway is eventually addressed, I suspect they’ll do everything they can to avoid using it, including maxing out the main spillway discharge.
This, at least, is what I’ve gleaned from reports.
With 45 years of engineering experience behind me, I’ve learned that Murphy was an optimist.
No lie. Especially when grandiose schemes to thwart Nature are concerned.
EWS, you win the thread. +1000
I notice that as of today, Wednesday, 15 April, flash flood warnings are now in effect for Oroville through Saturday. If I lived downstream from the dam I might be reluctant to follow their advice that is now safe to go back to my evacuated home.
Wow, just yesterday, the ‘experts’ on fake news TV were telling everyone the coming storms were going to be not very wet.
🙂 Missed it by two months!
I think it is safe for now…safe to go back and pack up as much stuff as you can save and truck out of your house.
As if San Francisco progressives, Hollywood liberals, and Sacramento politicians care about the residents of the Oro Valley or the farmers who need that water…
On February 9, inflow from the North Fork of the Feather River reached 175,615 cf/s. It has in the past flowed at rates as high as 317,500 cf/s. A lot depends on whether this is snow, rain, or warm rain that melts some of the existing 160% snow pack. Weather front #1 looks warm, #2 looks much cooler. For instance the 1964 catastrophic floods were warm rains known as the “Pineapple Express” over existing heavy snow.
Of interest is the little known fact that flooding from the Feather River drainage into the valley was mitigated by the early work on the Oroville dam during the winter of 1964/65. I just found that out since reading up on the history of the dam. It was said that the 1964/65 flood helped fill Oroville way ahead of schedule, but that the containment of the water alleviated problems downstream.. That should have been another clue to consider when assessing future risks to the dam.
In 1964-65 the entire Southwest was drenched in winter rains because of the volcanic eruption dust plus a la Nina. I grew up in the desert and missed school days due to flooding there that winter. We loved it as kids, of course.
Science is settled.
I think you’ll find that the saying is “it never rains but it pours”.
I think you’ll find that your viewpoint of the saying is incorrect:
http://www.dictionary.com/browse/when-it-rains–it-pours
I think you’ll find that the original English saying is “it never rains but it pours”. The later US version is “when it rains, it pours”.
http://www.phrases.org.uk/meanings/205100.html
http://dictionary.cambridge.org/dictionary/english/it-never-rains-but-it-pours
Well, we are in the U.S. So we use the U.S. version to talk about a U.S. issue. If the issue was in Britain, you might have a point.
Hahaha. The Brits school us! Yes, and let’s now discuss how it can rain cats and dogs. I recall, that saying was invented in Britain, too?
“England and America are two countries divided by a common language”
Attributed to George Bernard Shaw, in this and other forms, but not found in Shaw’s published writings.
Quote number 31 on Page 638, the fourth edition Oxford Dictionary of Quotations.
Anthony
Obviously I use the British version which apparently dates to 1726, which coincidentally was slap in the middle of the warmest decade in the CET record until the 1990’s. Incidentally CET has been declining throughout the 21st century.
Perhaps the US version has different roots as it seems to be related to an advert
https://www.quora.com/Where-did-the-saying-When-it-rains-it-pours-originally-come-from
Just shows how interesting the origin of these phrases are
Tonyb
“It never rains in California, but girl, don’t they warn ya?
It pours, man, it pours”- Albert Hammond
“I think you’ll find that your viewpoint of the saying is incorrect:”
I was recently researching the old claim that “The Rain in Spain stays mainly on the plain”.
It turns out this is completely false…the rain in Spain is mainly in the mountains and uplands.
Old sayings have a habit of not standing up to close scrutiny…except for the true ones.
What is true is that the rain in Spain falls mainly when it raining.
Bonus points to the first to name the originators of that last little ditty.
“When it rains, it pours”
I thought that was all about Morton Salt!
If my Scottish mother could see the Ochil Hills from the kitchen window it was, “Oh! It’s clearing up to rain again”!
Sounds like Scotland. And Scottish mothers. Famous for their succinctness, pessimism and ability to forecast weather.
Whenever an alarmist comes up with “but shouldn’t we do SOMETHING just in case?”, I’ll counter with “but shouldn’t we fix dams just in case your prediction of a permanent drought is wrong”…
Headline is misleading. The dam is not damaged in any way. What is damaged is a level control system along the lake shoreline separate from the dam. The lower portion of the primary spillway saw some of its concrete raceway collapse apparently due to undermining of water and erosion of its base. It is now determined that it can operate normally as long as we do not see any undermining of the upper portion. The lower portion presents a cosmetic scar but does not impact operations. The erosion there has been determined to have stabilized.
There was erosion on the upper portion of the hillside near the base of the overflow weir that was apparently caused by scouring. At the time Oroville was evacuated, the full extent of this scouring could not be determined. This was compounded by what appears to be the Sheriff of Butte County panicking and evacuating 50% of the population of the county all at once, including people who would have had several hours to get out of the way had the weir breached. Practically immediately after Oroville was ordered evacuated it was determined that the erosion below the overflow was not progressing as much as had been feared. After the water stopped and daylight came, it was determined that it was not as extensive as had been feared, either.
People need to understand that the weir is not just sitting on top of the ground. It goes pretty deep but exactly how deep I have not been able to find out. It is very likely anchored to bedrock. If it were simply sitting on earth, it would tip over when the water rises behind it. In any case, they determined that the scour was not in danger of undermining the weir and was likely caused by a gyre from water that had overflowed the berm that the weir abuts. That water basically went over the berm and some of it made a left turn and flowed into the area behind the weir making a whirlpool there which scoured out a hole. That could be mitigated in the future by placing something at the end of the weir that prevents water overflowing the berm making that left turn and forcing it to simply flow straight down the hill.
Most importantly, the DAM was never threatened. Had the weir failed, it would not have failed all at once, either. It would have undermined in one spot and that spot would have likely grown but the entire weir would not have failed instantly as was being implied by some reports. Some reports led people to believe a 20 foot wall of water would come instantly down that hill. It would have been most likely started as a flow much smaller than the primary spillway flow and gradually increased. While this was happening, the lake level would have been dropping reducing the pressure so the bigger the failure became, the less pressure would be on it. Worst case, one section of the weir might have failed.
The Sheriff of Butte County could very well have CREATED a disaster with his evacuation order. By evacuating the area all at once, he put about 100,000 additional people on the road *in front* of the people who were in greatest danger. Oroville and immediately surrounding area should have been evacuated first and then the situation re-assessed. Then evacuate people who would be flooded within 1 hour of a breech of the weir. Put everyone else on evacuation warning with the reasoning being that everyone else will have more than an hour to get out (and could spend the warning period preparing) and the roads in front of them would be cleared by then of earlier evacuees. The Butte County Sheriff’s mass evacuation order of 50% of the population of his county simply jammed the roads and slowed evacuation by people in the most at-risk areas.
Noted, headline updated.
Headline is misleading. The dam is not damaged in any way. What is damaged is a level control system along the lake shoreline separate from the dam.
In my book, the “level control system” is part of the dam, just as the safety valves are part of a steam locomotive boiler.
No, the level control system is not part of the dam (your book is wrong). Without the overflow weir, the water would still overflow the hill before it overflowed the dam. The level control system is used for flood control. It is how water is metered out gradually. The problem here was basically a single person made a unilateral call that amplified a bad situation and made it worse. Had that weir actually failed, the Sheriff’s evacuation order could have resulted in increasing the toll, not in saving lives. You do not put people on the road in front of the people who are in the greatest danger. You do not block the exits. That is what the Sheriff did. I have no problem with Oroville being evacuated, that was logical at the time. The problem I have is with areas that were not in immediate danger being evacuated (and would not be in immediate danger for several hours if the weir failed).
The 20 foot wall of water is likely understating the possibilities. In my 37 years of work I have performed many Dam failure models for the US Army Corps of engineers as well as other clients. Once a failure starts it progress quickly especially concrete dam failures. 30 minutes from the beginning to the full collapse of the spillway would be reasonable.
In reality the water does not proceed as a wall but the level would rise so fast you would not be able to escape. The wall of water is more of a theoretical exercise. The top of the flow has less friction so it should travel faster than the base. This should lead to a wall but no wall has been documented in nature
Watch videos of the Japanese tsunami. On the Fukushima flat plains, it simply flowed more and more and at first, did little damage and then more and more and more until it destroyed nearly everything.
There would not have been a 20 foot wall of water. That one scour could have potentially undermined the weir at one single point. That would have resulted in a leak but it would not have caused the entire weir to fail at once. Now it turns out after the fact, it wouldn’t have undermined it anyway.
An excellent comment – and a correct one … keep in mind that the parking lot side of the weir – where the scouring was occurring – has soil nearly to the op on the reservoir side … and at that point it is almost 500 feet of soil before reaching deeper water. There was erosion at the main spillway end as well … but that was almost entirely from the road washing out. The base of the weir there was hardened as part of preparations and that hardened area worked as intended.
Also – most people have little idea how massive that weir actually is. The section profile from the drawings show it as much as 50-60 feet tall and nearly that at the base. The profile also shows a 12′ wide apron 6′ thick on the down slope side (which can be seen in pics) and the 12′ wide by at least 6 foot deep “foot” at the rear – that would fit in a keyway in the footings to prevent movement …
And again … historic photos (and texts) show the spillway – main and emergency – where built in a small saddle or swale on an existing hilltop with bedrock underlying it …
Ok, Scott, the fear must have been that they were afraid the scour would cut around the end of the weir under the berm that the weir abuts. The water is much shallower there. While it would have resulted in an “uncontrolled release of water” because there is no gate there to regulate it, we aren’t talking about a lot of it (relatively speaking). It doesn’t look like the weir itself was really at risk at any point.
Crosspatch … the Sheriff was given info the scour was close to the base and it was progressing seemingly rapidly toward the weir. He was probably told by the water folks that the headcut could reach the base of the weir within 45 minutes and could undercut the weir and cause a failure.
The Sheriff made the safe call under the circumstances … that the scour all but stopped quickly thereafter was something that could not be predicted.
A extremely hard decision – with many lives at stake, and minutes to make the call.
crosspatch, you obviously think the force of water which scoured out the Grand Canyon is going to be stopped by some piddle little dam. Do you believe humans cause global warming too.
crosspatch you are right about what happened at the the spillways and the dam , but I tried to put myself in the shoes of the sheriff. When he was informed of the “break ” to the far side of the emergency spillway it was already getting dark ( 6 pm) and very little light to actually see what was going on. I think he made the right decision.
Look at this water content. I have never seen a number this high before for this region. That is 4 times higher than any of the storms for this winter to date. …https://earth.nullschool.net/#current/wind/surface/level/overlay=total_cloud_water/orthographic=-120.40,37.15,1348/loc=-123.936,38.567
Is this a case of, ” it’s worse than we thought” syndrome? Meanwhile billions have been spent on faux science that an astrologer could have done a better job. Where’s a drought when you need one? Climate change has diverted so much of our attention towards the wrong things. Rather than thinking the rains would never return, much like ‘ this drought is worse than the dust bowl’, it’s California, they should have used this time to prepare for the next round of rains. I guess the photo ops of reservoirs running dry were a self fulfilling predictions of permanent drought. Until it rained. I wonder how many of the faithful are having second thoughts on CAGW? After all, isn’t that the premise of CAGW, dry places get drier. And wet places get wetter?
I know how they can get out of this difficulty. Have a bigger disaster.
You’d think they’d have learned something from the overflow disaster in Australia, caused by a “are-in-a-drought-and-must-conserve-water” mindset.
I stand corrected Forrest.
Places that are alternately dry and wet will remain dry and then wet for, um…well…forever.
I agree…they should have been planning for the inevitable flood. Droughts always…ALWAYS end in floods.
The worse the drought, the worse the floods that will end it, although that last part is not as certain.
The funniest part…the same guy was Governor back in the seventies when a similar drought was blamed on global cooling. I do not remember what they blamed the floods that came in the year after the mid-1970s drought on.
Back then, people had some sense and did not try to blame the weather on anything but random chance and dumb luck.
Exactly.
The best time to prepare for floods is during a drought. Raising dams, strengthening dams, should be an ongoing obsessive occupation in California. The water system there should never be complete, but always seek greater safety, reliability, storage, and improvement.
I’ve also always wondered – during a drought, it is the ideal time to dredge sediment accumulated at the bottom of a reservoir, and dispose of it at the foot of the dam, to be eroded into the river by future outflows. This improves the environment downstream of the dam, extends the life of the reservoir, and improves storage. And yet, I can count on one hand the number of times I’ve seen this done.
Well, one knows Oroville has been affected when the price of crank rises.
How do you know?
That quote does not show up on my commodities listings.
They are a far cry from being secure downstream. It should NEVER have reached overtopping the E-spillway. It exists only to facilitate dam failure in the safest fashion. Officials must be charged, all the way to the Governors chair. Reckless endangerment is clear. GK
+10
I believe letting the emergency spillway operate was a blessing in disguise. It showed how vulnerable it is, and so now they have to beef up that hillside so that if it ever gets topped by 15 feet, rather than only 1.5 feet, maybe the concrete weir will survive. http://www.drroyspencer.com/2017/02/oroville-dam-crisis-eases-emergency-spillway-repairs-in-progress/
Roy … I agree – nothing like a real world demonstration of possible mass casualty to kick idiot career bureaucrats squarely in the, umm … seat of the pants.
In hindsight, as I’ve research and investigated this deeply, and now seen the results … it is inexcusable.
For the record – the “hillside” performed just fine. I don’t think there IS any real need to do significant hardening of the hillside itself … perhaps some intermediary coffer dams in the “channel” down hill to slow the water a bit … but we can see from aerials the channel itself saw minimal erosion and was down to bedrock (green rocks) quickly.
That the bench below the weir … from the base of the weir to the access road and just below the access road … was not only not hardened – but much of it was visibly weather surface rock (red/brown coloring) and even simple dirt … is inexcusable.
There are other concerns that were demonstrated as well. The ~800′ extension of the weir along the parking lot is a SERIOUS issue. It is not a weir – its a small bit of concrete buried a few feet in the ground. And the ground there is shown to be fractured and erode-able.
At just 1.6′ above 901 elevation water was going around the end of that area and down the access road. A look at that access road there shows it is elevated a long distance – over a ravine. Water flowing around the end of the parking lot weir had already cause significant erosion at the corner of the road – and had it washed the road out there would have opened a high velocity path.
That silly and useless parking like “weir” should be replaced with a REAL weir first, then extended further until it reaches high ground (the back of the parking lot. As it is a secondary emergency weir, it should be raised several feet or more as well.
Roy – it will only be a valuable lesson IF the dam survives! That is entirely up to nature NOW. We gave up human control many weeks/yrs ago. If heavy rain come… damn will go. GK
Scott Gates
“That silly and useless parking like “weir” should be replaced with a REAL weir first, then extended further until it reaches high ground (the back of the parking lot. As it is a secondary emergency weir, it should be raised several feet or more as well.”
I thought that was a design feature instead of a fault. If the emergency weir was only to be operated in a true emergency (water over the top of the dam) they then designed the weakest point furthest from the actual dam to minimize the total amount of water that would be released. Otherwise why would they have that crappy little wall at relatively the same height next to the incredibly substantial weir? The weir is 60 feet tall by 60 ft at its base at the widest point, the parking lot wall isn’t much more substantial than a retaining wall.
Eventually the lawyers will weigh in, so dam failure might not be needed for a learning experience that will not be forgotten by the participants. There are several CA state court decisions that might be applicable. Here are a few:
“Paterno” (not the State Penn Paterno) cost CA about $0.5 Billion, as in $500,000,000. Feather River levee failure downstream from the dam.
http://caselaw.findlaw.com/ca-court-of-appeal/1258864.html
http://law.justia.com/cases/california/court-of-appeal/4th/74/68.html
Paterno references include the Bunch, Belair, and Locklin decisions. Belair introduced “reasonableness”.
http://law.justia.com/cases/california/supreme-court/3d/47/550.html
http://web.stanford.edu/~meehan/class/mitjan2000/bunch.html
“In Belair v. Riverside County Flood Control Dist. (1988) 47 Cal.3d 550 (Belair), we held that when a public entity’s design, construction, or maintenance of a flood control project poses an unreasonable risk of harm to property historically subject to flooding and causes substantial damage to it, the property owners may recover damages for inverse condemnation under section 19.”
Locklin introduced “Locklin factors” for liability.
http://law.justia.com/cases/california/supreme-court/4th/7/327.html
Scott,
Your are either a troll, an idoit, or want to see a disaster with regards to a failure of the Oronco hydro project.
why criticize scott for what looks like a well thought out analysis of some design flaws in the emergency structures?
It’s not really a surprise that flaws can show up in emergency structures, since they never get tested in real world conditions, at least not until its too late to make any changes.
Scott and wws,
Read Jerry’s comment (Jerry February 15, 2017 at 4:13 pm)
As far as raising that ‘silly parking lot’, I would suggest lowering it to get the water flowing prior to topping the concrete weir. 10′ may be a good start and remove the pavement. Erosion invited. Leave 150 – 200 ft intact at the end of the concrete weir.
It’s just government bureaucracy working normally. Where’s the beef?
Indeed. When President Obama said “You didn’t build that”, the intent of his argument was that government provides the infrastructure and support for private citizens to pursue their business. More government provides more, so we should all be glad to have the opportunity to pay taxes.
Consider the St. Francis dam as how the government provides support. It used tax payer money to plan and build the dam, and forcibly displace homes and people that were in the flooded area. Then they granted building permits for new homes below the dam, and collected taxes from those homeowners. The dam failed, destroying those new homes and leaving 600 people dead. The government then used tax payer money to solve their liability.
The government built that!
No one seems to mention that the only thing that prevented an obvious catastrophe was that IT STOPPED RAINING. This week will test it again. Good luck.
The damaged main spillway is in no danger of failing. The bottom is destroyed but the top is sound. The only way we’ll have a disaster here is through human error and mismanagement of the problem. If for example they are so scared to run water through the damaged spillway that they allow the emergency spillway to come into use, erode, and fail.
Despite ~100,000 cfs flow for several days now the headcutting has stabilized. There has been no significant additional movement up the hill. This can be seen in photos that show the elecrtic towers
It has not been raining for the past several days.
To say it has stabilized and so that is that sounds like the kind of reasoning we heard in the lead-up to this disaster…which aint hardly over by a longshot.
For all anyone knows the next several weeks and months will see an amount of rain to dwarf what has fallen so far.
How many feet has the lake risen since January?
Do you think that same amount over the spillway will not do any further damage?
If you are an engineer…I would fire you for thinking like that, let alone insisting it is true to the public.
Simply repeating facts Menicholas … the main spillway has been running at 100,000 cfs for 80+ hours … there is plenty of photo evidence that the upstream breach has not advanced in days. That does not mean that will never change, but the best evidence right now is it is safely handling the flow …
At 871.92 the lake elev is down approaching 30 feet since the spillway was ramped up to 100,000 cfs – nearly 500,000 acre feet have passed thru the damaged spillway since flow was up to 100,000 cfs.
And they are close to having to dial down that 100,000 cfs flow. As levels get down to the channel cut on the lake side of the main spillway intake, the intake channel is constricted and is not hardened … they risk erosion of the intake channel if they continue to run at 100,000 cfs
@ Scott…it has been pouring rain for the last 2+ hours here in Trinity Co. The area of the Middle Fork Feather River is around 20 degrees F above average, 50F at the moment, and that is at 3500 ft elevation. Plus the forecast for that area is for 10 days of mostly rain, maybe some snow next week. This is far from being over. The Middle Fork is a large portion of the Feather River drainage. They better keep that flow running strong.
goldminor … I agree … but at present they are in a dramatically better situation … the last storm dropped something like 15″ and eventually increase reservoir levels 50′ … but that was at limited spillway flow …
At the press briefing earlier today they noted this storm is predicted to cause 100,000 cfs peak inflow when the water makes it to the reservoir. And right now they have 30′ of freeboard – over 500,000 acre feet of storage …
if the spillway generally holds they can come very close to holding the water level steady … even if they have to scale flow back, still a lotta storage avail … I am cautiously optimistic …. but Mother Nature can be temperamental so nothings guranteed
Scott, about 30 feet of that lake rise came in the almost 3 day period when they shut down the M.S. and did emergency prep on the E.S.
If they can continue to run 100K CFS they will likely be fine. At about plus or minus 75K CFS ( inflow vs outflows) the lake level changes about 9 feet a day.
What else would you expect from Jerry Brown?
50,000 cu ft/sec of water, falling 600ft, according to my calculations (which I have to admit are error-prone and need checking by somebody that makes fewer errors than me) results in a release of 2.5GW of power. Or, over 24 hours, about 100ktons (TNT equivalent).
So, although most of the released energy will result merely in the water temperature being raised a bit, it’s still not suprising that structures of earth or concrete get torn up. And it shows how the upkeep and operation of dams should not be left in the hands of buffoons.
I can confirm that your calculation is wrong, sorry Martin. 🙂
50k cu ft/s is (time to go to SI units, folks! 🙂 ) 50k x 0.02832 m3= 1415 m3/s times 600 ft (183 m) is 2.6 megajoules, or per second 2.6 MW (a factor of 1000 lower than your calculation, it seems).
Multiply this by 86400 seconds in 24h and you get 22.4 gigajoules (GJ).
100 kton are 4180 GJ… so 22.4/4180=0.00535 x 100 kton, or 100 kton/187 (rounded).
Still a lot of energy, but less than what you thought.
Cheers.
I think you are forgetting to convert volumetric flow rate to mass flow rate.
PE = mgh = (50E3 ft^3/s) * (0.02832 m^3 / ft^3) * (1000 kg/m^3) * (9.81 m/s) * (600 ft) * (0.3048 m/ft) = 2.54E9 J/s as Martin A calculated
(2.54E9 J/s) * (86400 s/day) / 4.18E12 J/kiloton) = 52 kiloton TNT equivalent / day.
You are absolutely right, Joe. I forgot the ‘g’ factor in the multiplication of terms, so 10x more. Apologies.
Almost 7 Hiroshimas.
A friend from college rose to became Colorado River Watermaster. His overarching mandate was to make sure he didn’t get “behind the power curve” (to borrow from pilot jargon) and get caught with more water behind Boulder Dam than he could release in time to avert an emergency. Only one time in the history of the dam did the emergency spillway ever come into play, spectacularly, and it was something of a scandal on his watch.
So, ignoring the maintenance issues, why didn’t the overseers of Oroville Dam start drawing it down many weeks ago, when we were already in the well-predicted series of “atmospheric rivers”? They should have seen this coming in plenty of time to avoid the uncontrolled spillover. Yes, the main spillway failure would have still occurred, but that wasn’t the dangerous phase of this debacle. Asleep at the switch.
Why worry about too much water behind the dam when you’re in a permanent drought?
Reminds me of a scene in “Nevada Smith”. Pat Hingle (a trustee) tells Steve McQueen (a prisoner, assigned night watch in the kitchen) “Boy, you got one job – don’t let that fire go out.” “Well, when do I sleep?” “Just don’t let the fire go out.”
Just don’t let that dam overflow.
Inappropriate use of the Precautionary Principle, I guess. It was a 50-50 shot. The gamble was no rain, the reality was lots of rain. That’s the problem with using a principle based on wild guessing and no evidence.
But Sheri, NOAA predicted a series of atmospheric rivers, and after the first such event or two, it should have been obvious what the implications of the subsequent events would be for the reservoir. “Your Job #1: Don’t let the dam overflow. Jobs #2, #3, etc: See Job #1.” There’s no excuse for getting caught by surprise.
A drought mentality is a mitigation factor when sentencing, but should have no affect on a guilty verdict of Reckless Endangerment.
In addition to that, once they did start letting water out and part of the spillway collapsed, they were afraid to let too much water out because that would have increased erosion and caused pollution downstream.
I think in the case of the Brisbane floods it may have been more willful. the alarmists like chaos so a flood is as good as a drought for them. when people feel entitled there is nothing they wont justify to themselves.
Hopefully Jerry didn’t spend all the pseudo bullet train money because that’s one big lawsuit the state is going to have to cover…DWR staffers stealing money for years via apathy to their jobs…what a sad state of affairs that the down-river citizens will have to endure
And with several hundred feet of snow in the Sierra mountains and we get a fast snow melt…Noah, build that Ark fast!
Well, about 200 inches actually:
About 2x normal for this date:
https://www.wcc.nrcs.usda.gov/ftpref/data/water/wcs/gis/maps/west_swepctnormal_update.pdf
Noah was sailing the Ark over the Kerry Mountains at the height of the flood, and the top of Carrauntoohil (the highest mountain in Ireland) was sticking out of the water as an island. A sheep farmer was standing on the island and he hailed the Ark: “Ahoy there, can you give us a lift to Killarney?” Noah’s son said: “I’ll have to ask the Boss”, so Noah came out and told the farmer, “Sorry, no can do, we have strict rules on this boat: only two of a kind, and none of your kind”. So the Ark sails on past, and the Kerry sheep farmer shakes his fist after it, saying: “You can shtick your lift up your jersey, shure ’tis only a shower anyway!”
Stupid gov for dumber constituents enables the ingnorance that empowers the arrogance about man made climate change verse scientific fact. Cali gets what it deserves.
.
Oh yes, the crack in the spillway should have been repaired when it was noticed in 2012, there seems to have been an oversight.
The spillway was inspected annually. And there were repairs made in 2013 (among other times) … sorry, your claim does not compute.
The experts have already admitted that the last inspection was a cursory affair. They should have understood the risk of having another winter similar to 1996/97. Now with rains that did not reach the levels of rain back 20 years ago, the risk of a catastrophic release of water still hangs in the air.
“And there were repairs made in 2013”
They should have used something better than Superglue.
What is the catchment are of the dam in relation to its current surface extent?
Two inches of rain on the catchment is far more than 2″ on the water level in the dam. For the moment they seem to be able to maintain a steady flow of c. 100,000 cfs and have gained themselves a bit of breathing space.
Maybe they should be doing some cloud seeding well up wind on the incoming weather fronts.
Here is a graph I did of the current state of play, earlier today.
The North Fork Feather Watershed is approximately 2100 square miles. I do not have elevation data that would determine runoff events for various snow lines.
Catchment is Roughly 150x size of lake.
Dave Kelly linked this radio interview with a dam engineer in the last thread. very informative
https://youtu.be/rl7Sm15unPQ
Right at the end of the podcast we have another well known saying:- “Penny wise pound foolish”.
Excellent interview, frightening but not surprising in California.
jw
A terrible interview from a pompous, fear-mongering, self-promoting jerk – alleged expert or not. He actually told people to trust him and not local officials.
“alleged expert or not. He actually told people to trust him and not local officials.”
Did you forget to add /sarc
Highly recommended! This guy (Scott Cahill) knows the specific geo-technical details associated with the Oroville dam construction, primary spillway, and emergency spillway. Combined with his training and experience, he describes the problems in terms most folks can understand.
No JMac he does not. He admits he does not have soil maps or topos. And he initially didn’t even understand the type spillway.
And no clipe, I did not forget /sarc … he actually and seriously told people not to believe the local officials and to trust him instead …
Yes, I am not sure the emergency spillway could every have functioned properly. One section emptied onto bare earth, seemingly with no foundations under it. And the waterflow for the entire length of the spillway was then directed to the right as we look at it, along the base of the spillway, and then drained downhill.
But what into? I could not see a culvert under the road. So the spillway appears to have been designed just to cross over a road and flood across some bare ground. But water will never do that, it will cut a valley, which is exactly what it did. So how did this emergency spillway ever pass any inspection?
Does anyone have any good photos of it, before it was damaged?
R
The emergency spillway if built on rock but it is weathered rock which does not resist well to the immense destructive force of falling, surging water.
It seems that they regarded having one as a mere formality and never expected to actually use it.
Here is an image after the damage. So the emergency spillway waterflow runs over the spillway, and runs away from us towards the main spillway. It then does a 90º right turn and heads towards the small road. But then what? Was there ever a culvert under the road? It seems the flow was designed to just wash the road away and gouge out a valley. Which is what it did.
And the diversion away from us, along the base of the spillway, was also inadequate. You cannot expect a soil mound to stop boiling white-water. So without anything there to stop it, the water to the left of the spillway just carried straight on, and started gouging out another valley, where it was not supposed to be at all.
And both of these erosion patterns would have eventually undermined the emergency spillway dam. Which is the same as how New Orleans was flooded. As I understand that event, the overtopping of some concrete levee walls was not a big problem, as the pumps could easily deal with that. But the overtopping water gouged out a hole at the base of the levee wall, and once deprived of its foundations the levee wall collapsed. And now there was a complete flood. And the same would happen at Oroville too, if those erosion hotspots reached the base of the spillway.
http://www.vosizneias.com/wp-content/uploads/2017/02/APTOPIX-Damaged-Dam_sham-1.jpg
The emergency spillway is designed and intended for rare emergency use. Some erosion of the hillside is considered acceptable. That said – the entire hill is very hard bedrock. Some of the top layer is weathered and is susceptible to erosion. Some topsoil will always erode.
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And we can clearly see that even with the water from the emergency spillway concentrated almost entirely in one channel – the area of hillside below the access road shows minimal damage in the channel. Larger hi-rez aerial images show the bottom of that channel is green – meaning bedrock … which did not erode.
The flat bench below the emergency spillway and the road should have been better hardened. It is most rock – with bedrock not far below. That bench should have been hardened … for several reasons.
One to minimize erosion. The area below the main spillway side of the emergency spillway WAS armored before the emergency spillway becoming active – and operated as designed – there was no erosion in this armored area.
The second reason is design related. A big part of the operation of a weir type spillway is a flat, laminar flow. That the water follows smoothly over the spillway and down its face and then spreads in a flat sheet down slope is an important consideration. Where the flow is not smooth, erosion is more likely and once erosion begins it exacerbates the situation by head cutting upstream.
The bench below the weir is stepped in height across its face. That in itself creates lateral current at the sideslopes. In particular at the parking lot end where the emergency “ogee” style (curved) weir meets the small concrete wall net to the parking lot.
That junction created a jet at an appx 20-30 degree angles to the flow over the main weir. At the same point water flowed down the sidelsope between the main weir and the parking lot weir …. again creating a lateral flow – across the laminar flow down the main weir.
It is exactly there were the erosion area of concern was created.
The bench below the main emergency weir should have been flat, the sideslopes minimized across it, and it should have been armored down to an across the road, and the roads downslope.
The Sierra club and other pushed for the entire hillside to be armored – which has been shown to be unnecessary. I believe that push took focus away from the bench area which WAS important.
This image shows those flows:
This image shows the resultant erosion and the flows that created it:
There are other issues and areas that became apparent as well – for example significant problems with the silly concrete wall along the parking lot – and the fact it does not continue to higher ground. Something that could have been seen on a topo map – IF you ever expected the emergency weir to see a 1.5 foot ‘head’ – a lake level 1 and a half feet higher than the weir …
Hindsight is always 20/20
The road was always sacrificial … it was built with small rock base. There was an outlet under it but it was designed to drain rainwater not spillway flow.
the majority of the “cut” at the road is just from the road washing away … what is left is largely bedrock. The section of the weir at that end DID have a hardened area at its base and that performed well.
They have built a new haul road closer to the weir in that same area. It is built of larger boulders and is lower.
The cement hardening has been extended in that area as well.
>>the majority of the “cut” is just from the road washing away.
Rather more than just the road washing away. The rapid erosion causing such a deep crevasse rather demonstrates that the rock upon which the entire dam complex is built is friable, and will wash away quite easily.
https://www.metabunk.org/attachments/img_7413-png.24548/
Let’s try that image again…
https://www.metabunk.org/attachments/img_7413-png.24548/
Try this one…
I have a bunch of photos before and after and historical here:
https://www.facebook.com/scott.gates.750/posts/10154887673187457
A detailed discussion with much info avail here:
https://www.metabunk.org/oroville-dam-spillway-failure.t8381/page-15
Nice pictures Scott.
In this original picture of yours, I see no provision at all for run-off from the emergency spillway. No channel at all – just the road for the water to run down. But if the emergency spillway was only ever designed for very low discharge rates, then why was it so wide? Why build a spillway 100m wide, if the ground below could never cope with that volume? And why did no subsequent inspection highlight this design flaw?
The emergency spillway water flows down the hillside unrestricted. If you understand topos and review them you can see exactly where the water will flow down the hill. And i you then pull up any of the many images during and now – you’ll see the water followed that path.
You’ll also see there was minimal erosion in that narrow path … AND you will see its all mostly green-blue in color now – after the event. Which means good hard bedrock
You can get great views of the whole thing by just typing Oroville dam into Bong r google and then clicking on tabs.
But for even better views, go to bing maps, type in Oroville dame, and then click on Birds Eye view.
This opens a page in which virtually the entire US has been photographed by low flying planes, from four angles.
As you rotate the view on the compass, you will get shots from different angles from the plane.
This are low enough and of goon enough resolution that you can see details as small as a few inches…people, cars, trailers backed up down the boat ramps…
Looks to have been done when the lake was tens of feet lower.
Since looking at this…that parking lot seems less dangerous…on the lake side it is not deep and banks very gradually down to a bunch of other parking lots and ramps for hundreds and maybe thousands of feet.
The water flowing over that parking lot would have had a lot of ground to cut through.
The lake side of the spillway seems to be made of dirt however, and if it was undercut it could be very bad.
“If Trump turns off the satellites, California will launch its own damn satellite,” roared Brown to the crowd.
Presumably he will also be shouldering the cost of his failed and decrepit damn dam. Not expecting the rest of the nation to foot the bill for their mismanagement.
So just to get this straight, they are forecasting 11 inches of RAIN in the catchment over 10 days? Or is that 11 inches of snow? If 11 inches of rain fall and some snowpack melts with it, you’d might as well be packing everything now if you’re in the valley.
11 inches of precipitation. It’ll be snow above about 7K feet, which should total several feet, and rain below that. The inflow into the lake will rise dramatically although the lower snow levels will prevent even worse flooding. The last storm had snow levels around 9K feet.
It depends on how much of that precipitation flows to Lake Oroville. With the soils in the catchment area pretty saturated, the percentage could be high. Over a 3607 square mile catchment area, and 640 acres per mile, 11.62 inches of rain is a total of around 2.25M acre feet of precipitation, or around 225K per day. If all of that flowed into the lake evenly, that would be around 113K cfs. As long as they can keep releasing 100K cfs from the main spillway, they should be OK, but that is not accounting for any snowmelt that might be added to that.
Why wasn’t there preparation to clear debris from the inflow ports for the dam? Someone here pointed out that no water is flowing through the dam’s turbines, because there is too much debris blocking them. Possibly the people in charge didn’t anticipate that the dam itself might not be contributing to draining the lake.
I read that the dirt and rock eroded when the main spillway failed has caused the water level at the base of the dam to reach a level high enough to prevent the power turbines from being used. So not only are they unable to generate electricity they also are kept from releasing another 15K cfs through the power generation facility.
The debris is the eroded mess from the failed spillway. Half shot downstream, and half shot up into the diversion channel. Now theynhave to remove that debris bar before the powerhose penstock can be opened.
Why?
@Menicholas if silt backs up into the turbines, the power plant will be destroyed and they will lose the ability to remove 15K cfs for a long time until the power plant is repaired, in addition to being without the power.
I never see any mention of the fact that they’re releasing over 60 billion gallons of water per day. Water that California needs since, according to the the experts, we’re still in a drought emergency.
This story won’t be over until June and then it’ll shift to the monumental repairs that will be necessary. I have to wonder if they’ll go ahead and line the emergency spillway with concrete as recommended 12 years ago.
Well, the erosion pattern would indicate where that might go…
The hillside has performed just fine. Even with flow concentrated in mostly one channel. The hillside is mostly bedrock and needs no hardening.
The bench from the weir to the access road DOES absolutely need hardening. They have already done that for much of the area. They need to rebuild the road and harden it, and a short section downslope of the road … the hillside will be fine.
@LoganSix – The main spillway is not “eroding the base of the dam” … and that main spillway has been running at a non-stop 100,000 cfs now for days with little or no additional damage. The fractured rock and soil has been flushed out and it is now down to bedrock (the blue/green rock) which isn’t going anywhere.
@emsnews and @logansix – the emergency spillway repairs are much more than a ‘a puny pile of rocks – dropped in the holes’ … again, the spillway is built largely on bedrock. Its location was originally a saddle in an existing hilltop. The erosion seen was the top layer of fractured rock, dirt fill, and the road base for the parking lot access road.
The erosion areas near the spillway weir were, where rock was exposed, filling with large and smaller boulders which was then filled with cement. Areas of dirt and fill were excavated, and those too are being filled with boulders and cement.
The area at the base of the emergency spillway weir near the main spillway had been similarly hardened with rock and cement before the spillway was used and those areas suffered no erosion. That area has been strengthened further, including the side slope of the roadway … and a new access road has been built, with heavy rock this time – not just compacted small rock fill. presumably that will be hardened with cement today as well.
The flow over the emergency weir is important to note … at its peak – when the lake level was 1.6 feet higher than the top of the weir – was just 12,000 cfs … about 12″ of the main spillway flow. And that was spread across 900′ of the emergency weir. During much of the release over the emergency spillway the flow was well less than 10,000 cfs.
Still significant – but not huge. It should be noted that other than in the bench area just below the emergency weir, the water caused minimal erosion of the hillside below – despite all of the flow over the weir consolidating into mostly one channel. Aerial views show that channel hit green bedrock quickly.
In no way am I saying this isn’t a typical California “clusterf***” … it certainly is. The whole emergency spillway situation – and the arrogance of those responsible for decades – is inexcusable.
But reality is important for the present as well … and that reality is the cement hardened areas performed during the release. And not only has the erosion in the bench below the weir been repaired and hardened with cement, but I believe much of the entire bench will be as well before they are done.
There are no guarantees in life, but the repairs made, along with other actions, and the forecast all point to the high likelihood the danger is minimal.
There is an excellent technical discussion here on the issue:
https://www.metabunk.org/oroville-dam-spillway-failure.t8381
https://github.com/axibase/atsd-use-cases/tree/master/OrovilleDam
Based off of our estimate, for every inch of rainfall at the Oroville dam, 136,790.5 acre-feet will be added to the reservoir. As of 5:00 am PT on February 15th, there was 307,145 af of space left in the reservoir before it reaches its threshold. The maximum outflow per day that the dam is able is push out is 142,034 afd, which was achieved on February 14th. So, if we multiply the rainfall per day by our acre-feet rate (136,790.5) and subtract the maximum outflow, we should get a storage amount added per day. If we then divide the storage added per day, we should get a answer for how many days it would take for the storage to reach threshold capacity again. Below is a table showing the amount of time for the dam storage to reach threshold capacity for a given amount of rainfall per day.
Rainfall Storage Added/Day Remaining Storage Time to Reach Threshold
1 inch per day -5,243.5 307,145 No storage gain
2 inch per day +131,547 307,145 2.334 days ~ 56 hours
3 inch per day +268,337.5 307,145 1.144 days ~ 27 hours
===================================================
So is this bunk too?
I moved out of California during Moonbeam I. I have never regretted it. Why the people of California chose to elect the idiot a second time (actually 3rd and 4th) shows that you do not need brains to live there. But while it is normal to get mad and start demanding accountability and answers, the crises is upon us. Those 200k folks have lives that may never be the same. And right now, we have a slow motion wreck descending upon them. We can only hope that the spillways hold up as they will get used.
To those on the left, stop reading, because you do not want to see what I write next.
I will pray for all those people that hopefully the dam system has enough left in it to save them from further harm, for their lives and property. I pray that those without agendas and with competency can be given a free hand to do what is necessary to safeguard all.
+1776
“resulting from poor planning, lack of maintenance”
You see these words plastered all over the news. Many here are saying that they should have never let the dam fill up and that California let it fill up do to drought concerns.
The fact is the dam this year is being operated the say way as they have been doing for 50 years. Every year they allow 4/5ths of the lake to fill and leave 1/5 of the lake unfilled for flood control. Only when the rain stops and snow melts do they allow the rest of the dam to fill. The only difference is that this year we are seeing rainfall at 200% or normal which no one was predicting. The lake has gone from almost empty to full in record time. Water inflow has been exceeding what the original designers were expecting for over a month. Clearly the dam need a bigger spillway but no one knew that until now.
In the San Francisco bay area right now there are at least 6 dams receiving earthquake retrofit. One is being completely replaced. At the time those dams were made we didn’t know that much about earthquakes. Now we do and now were are upgrading them. Some also had spillways that were too small. With the earth quake retrofits those spillways are also being upgraded. Oroville dam has not been identified as needing an earthquake retrofit. Is Oklahoma doing anything to address the increasing earthquake threat in there state? Or what about alll the other states in the central and east cost which also have earthquake faults? Clearly california is addressing infrastructure issues as quickly as it can. Yes improvements can be made but clearly we are not the worst state.
We also have repaired or replaced most bridges in the state because of the better understanding of earth quakes. The includes almost all of the freeway overpasses in the state. Thats a lot of bridges.
As to Maintenance No reports of any maintenance lapses have surfaced. They have been performing regular inspections since the dame was built. People have been saying that they should have inspected the spillway and repaired it before it failed. The trouble is that a visual inspection cannot tell you if there is anything wrong underneath the cement. No one has x-ray vision and even the best instruments available may have not detect the void that developed under the cement. In fact the void that caused the spillway damage may not have even existed until the record setting rains arrived this year. 90% of all maintenance starts with a visual inspection. Unfortunately visual inspections don’t catch 100% of all problems.
Yes the warnings about the emergency spillway were correct. However at the time all the experts said it wasn’t necessary and that the dam meet FERC design standards. Clearly the design standards were not sufficient. Now every dam in the US will need to be evaluated. That has already started in california but will it be done in every state?
Its easy to criticize the designer that designed and built the highest dam in the US with nothing more than a slide rule, pencil, and paper. Yet clearly they did very well with no long term weather data, no modern computer models and no seismic survey equipment available.
An excellent comment Steven. I have read much of the documentation and commentary on construction and design. The planning started in the early 50’s and was extensive. The accomplishments they made considering the tech then vs now is amazing.
The hindsight of fear always opens eyes to possibilities that may never have been considered …
“The only difference is that this year we are seeing rainfall at 200% or normal which no one was predicting.”, no one except me. …https://disqus.com/home/discussion/cnbc/sierra_nevada_snowpack_lowest_in_500_years/#comment-2253607967
They should have been well aware of the potential danger after the major winter of 1996/97. The emergency spillway came very close to releasing water during that huge rain storm, and that was with the turbines still flowing water and the spillway functioning properly. They were very worried at that time.
crosspatch postulated that the weir is anchored to bedrock. Much depends on the design details of that anchoring. I hypothesize that the engineers did not include the mass of the downstream hillside buttressing the weir in their calculations that the weir could withstand the hydraulic head.
I’m guessing that because they didn’t concrete line the slope below the weir. They either assumed that flows over the emergency spillway would always be gentle; or they could fully lose the downstream hillside. Apparently by TPTB reaction this last week, they don’t want to lose the hillside. TPTB are terrified of the exposure of the weir foundation to falling water forces.
Nevertheless, the engineers probably did not fully analyze the effect of scouring and undermining at the base of the exposed weir, with enhanced water fall forces.
There is probably a UC Engineering library somewhere that contains the design details, all in a big book. Then again, they might have removed those books to prevent terrorists from exploiting design vulnerabilities like “a small [hydraulic control] port, right below the main port. The shaft leads directly to the [weir control] system. A precise hit will start a [scouring] reaction which should destroy the [dam]. Only a precise hit will set off a [scouring] reaction.” The book is probably stored in the CA DWR data storage facility in Scarif (Sacramento CA Regional Information Facility).
As to the loss of the raceway. The engineers did not want any modification to the main dam left side buttress. That raceway went all the way to the riverbed and was supposed to handle 250K cuft/s. That left-side buttress has now been hydraulically modified. More design assumptions invalidated.
Good luck California. Pray for drought. Hope is not a successful survival behavior.
From that “book” which is available:
“Page 92 …
The spillway for Oroville Dam (Figure 76) is locat- ed in a natural saddle on the right abutment of the Dam. This location allows spillway discharges to enter the River, well downstream of the toe of the Dam and powerplant tailrace. The spillway consists of a combined flood control outlet and an emergency weir. The flood control outlet consists of an unlined approach channel with approach walls shaped to make a smooth transition to the outlet passage, a headworks, and a chute.
The headworks structure (Figure 77) has eight outlet bays controlled by top-seal radial gates, 17 feet – 7 inches wide by 33 feet high. A concrete chute (Figure 78), 178 feet – 8 inches wide, extends 3,050 feet from the flood control outlet down the side of the canyon to a terminal structure (chute blocks) where the water plunges into the Feather River.
The emergency spillway is an ungated, concrete, overpour weir located to the right of the flood control outlet and is made up of two sections ( Figure 79) .
The right 800-foot section is a broad-crested weir on a bench excavation.
The left 930-foot section is a gravity ogee weir up to 50 feet in height. Except for a narrow strip immediately downstream of the weir, the terrain below the weir was not cleared of trees and other natural growth because emergency spillway use will be infrequent.
The flood control outlet was sized on the basis of limiting Feather River flow to leveed channel capacity of 180,000 cfs during occurrence of the standard project flood (peak inflow 440,000 cfs).
This limitation applies at the confluence of the Feather and Yuba Rivers approximately 35 miles downstream of the Dam. It was estimated that a runoff of 30,000 cfs could be expected within this 35-mile reach of the Feather River during the standard project flood. Therefore, the flood control outlet was designed for a controlled release of 150,000 cfs.
The normal reservoir water surface previously had been set at elevation 900 feet. To meet these criteria, a flood control reservation of 750,000 acre-feet was needed. The criteria also governed the size and location of the flood control outlet gates.
The outlet must release 150,000 cfs at water surface elevation 865 feet to control the flood shown on Figure 80.
The standard project flood has a probability recurrence interval of approximately 450 years. If data received indicate a flood is developing greater than the standard project flood, release through the flood control outlet may be increased above 150,000 cfs but may not exceed 90% of the inflow.
When the reservoir fills above elevation 901 feet, flow occurs over the emergency spillway. The emergency spillway, in conjunction with the flood control outlet, has the capacity to pass the maximum probable flood release of 624,000cfs for the drainage area (peak inflow 720,000 cfs) while maintaining a freeboard of 5 feet on the embankment.
The maximum probable flood has a probability recurrence interval in excess of 10,000 years.
Hydrologic and hydraulic data are shown on Figure 80.
Various types of spillways were studied and modeled to arrive at the final structure. The original design consisted of a control structure with radial gates to pass the total spillway design flood. A short concrete apron was to extend downstream from the control structure, and then the flows were to be turned loose down the hillside in an excavated pilot channel. As the spillway would operate on the average of every other year, this plan was determined to be unacceptable based on the large quantities of debris that would be washed into the Feather River and could ultimately affect power operations. Adding a converging concrete-lined channel and chute to the original headworks structure created major standing-wave problems throughout the system.
These problems were resolved by separating the flood control structure from the spillway structure as shown on Figure 76. The rating curve for the flood control outlet (Fig- ure 81) is based on these hydraulic studies.
Concrete for the spillway chute, weir, and flood control outlet structure above elevation 865 feet was specified to obtain a strength of 3,000 psi in 28 days; concrete for the lower portions of the flood control outlet, below elevation 865 feet, was specified to obtain a strength of 4,000 psi in 28 days; and concrete immediately behind the prestressed trunnion anchorages was specified to obtain a strength of 5,000 psi in 28 days. Steel reinforcement conforms to intermediate or hard-grade billet steel as specified in ASTM Designation A15 or A408. Post-tensioned tendons for the gate trunnion anchorages have an ultimate strength of 160,000 psi. Structural steel for the main members of the radial gates and bulkhead gates conforms to ASTM Designation A441. Secondary gate members and trunnion beams are of A36.
Emergency Spillway. The grout curtain was continued under the left reach of the emergency weir near the upstream face, and formed drains are used under the downstream half. The crest of the emergency weir to the right, which is only 1 foot above the excavated channel, is keyed 2 feet into the foundation. Both weir sections were checked for overturning and shear friction safety factor and found to be satisfactory.
Pg 185:
Spillway Clearing. Approximately 115 acres, 40 in the spillway and chute and 75 in the emergency spillway area, were cleared of brush and trees. The area below the emergency spillway was not cleared.
Excavation. The three major methods used to excavate the spillway were as follows: bottom-loading scrapers and pushcats, a loader with cats feeding the belt and bottom-dump wagons hauling the material, and two large shovels. In general, the scrapers were used to strip the area to rock. The shovels were used to excavate the rock after it was drilled and shot. The loader was used similarly to the scraper operation, the main difference being that it was possible to work this operation in rougher terrain as up to eight dozers were used to push material to the feeding hopper.
A road was graded out below the hopper and the bottom-dump wagons could drive under the hopper to load. All drilling for blasting was done by percussion type drills mounted on tracks and powered by air. The patterns varied greatly from area to area. The most generally used pattern was 8 by 8 feet; however, patterns ranging all the way from 2’/2 by 2/4 feet to 15 by 15 feet were used depending on the area, type of rock, and excavation objective.
Excavation near structure lines had to be controlled to avoid damage to the rock to be left in place, and 840,000 tons of riprap for Oroville Dam had to be produced.
In part of the emergency spillway, an additional 10 feet of excavation was required to reach acceptable foundation rock, resulting in considerable additional time for excavation and placement of the backfill concrete to subgrade.
Approximately 90% of the chute foundation required blasting to reach grade.
The only extra excavation directed was removal of a few clay seams in the foundation and a few areas where slope failures occurred.
The depth of overburden in the approach channel was deeper than estimated and the slopes had to be changed from ½ to 1 to 1½ to 1 to prevent sloughing as the excavation reached the final grade.
The slopes in the flood control outlet gate section proved to be of a lower quality rock than anticipated. There were several large seams running parallel with the chute. The planned anchor bars were replaced with grouted rock bolts, pigtail anchors, and chainlink surface covering in that area.”
https://ia800302.us.archive.org/3/items/zh9californiastatew2003calirich/zh9californiastatew2003calirich_bw.pdf
Scott, thanks very much for that, exactly what I though should exist somewhere.
Design details:
1. “The crest of the emergency weir to the right, which is only 1 foot above the excavated channel, is keyed 2 feet into the foundation. Both weir sections were checked for overturning and shear friction safety factor and found to be satisfactory.”
2. “The emergency spillway is an ungated, concrete, overpour weir located to the right of the flood control outlet and is made up of two sections ( Figure 79) . The right 800-foot section is a broad-crested weir on a bench excavation. The left 930-foot section is a gravity ogee weir up to 50 feet in height. ”
Figure 81 shows the right weir with keyway. Figure 81 Section B-B does not show the key, but it talks about “grouting details”. I don’t see evidence for trunnions going from the weir into bedrock. So I can see why they are concerned about undermining. The weir is sitting on a flat bench,held in place by shear at the foundation, and mass for overturning. It can’t be allowed to be undermined.
Pray for drought, prepare for rain.
Also note the flood details. A controlled spillway release of 150K cuft/s would be required every 450 years, for a “standard project flood” peak lake inflow of 440k cuft/s. An emergency spillway release will be needed for all larger, up to a peak 10,000-year inflow of 720,000 cuft/s. I do not think the emergency spillway can be counted on for that flood. Time to steal money from the “Bullet Train to Nowhere” to retro-fix this dam. Fast trains are too hard for governments. Governments are really good at pouring concrete.
I knew a guy in the early 1970s who had worked at CA DWR. He talked about “shot duck syndrome,” people who had got as far as they wanted, and just went into glide mode for the rest of their working lives.
The damage to the spillway seems to be just below where the gradient of the spillway increases. This might have caused suction that “lifted” the concrete. Concrete has no strength in tension. You avoid this sort of thing with a dentated sill, or better still designing a spillway where the gradient is constant.
It is actually called an “incompetence syndrome”. As long as you are competent, you get promoted. Once you reach a level for which you are no longer competent, you stay there. In a sufficiently old organization, everybody sits just above the level of their competence.
“incompetence syndrome” == “The Peter Principal”; People are promoted to their level of incompetence.
The St Fransis dam failed because of geology. It was built on a fault plane. After fill, the gouge of the faultplane was eroded and it propogated upwarded, destroying the dam.
My big worry is that the Feds will pay for the fix. This is entirely California’s problem. If they have the money for a train to nowhere, they can fix these spillways themselves and leave the rest of us out of it. Until California becomes more responsible, giving them money is a total waste.
My philosophy is that if they don’t want to pay for it, there is no reason the rest of us should either. If it doesn’t matter to them, it shouldn’t matter to us.
I’m a Californian. I agree. Gerry says we are rich (despite the debt), and we blow money on bullet trains, windmills, and solar. We are able to divert money used on whimsical projects to necessary infrastructure. The Fed should not be guaranteeing our silliness. Take the money required from one of the above projects.
Frankly, the money to repair the spillway and upgrade the emergency spillway is a drop in the bucket compared to what we’re blowing on those silly projects.
let me third this comment: make Moonbeam come up with the $$$ to fix his F up…
he built it, he can fix it, and i’m a native. #HighSpeedFail can cover this tab.
How about a bullet train to Oroville. That oughta do ‘er.
IMO the Metabunk forum discussion establishes at pages 12-16 that the emergency spillway will fail when used, most likely from the west side parking lot. Look for the term “weathered bedrock”.
Overflow water will find the lowest path downhill and erode around any newly dumped rock and poured concrete. One of those paths will erode back up when it gets steep enough and undermine some part of the parking lot or even the concrete weir, resulting in structure failure. Any unexpected sideways flow someplace would greatly exacerbate this.
Scott Walker is correct that this won’t happen fast. Hopefully it will go slowly enough so that mass evacuation can take place now the Butte County Sheriff understands that outgoing traffic should be opened on both sides of all roads and highways.
The problem is that six week remain in the rainy season, plus there are snow pack melting issues.
Tom … I’m a part of that thread at Metabunk – and I don’t think it establishes anything of the sort. It discusses weathered rock as an issue but not that the emergency weir will fail.
In fact all the evidence shows it is NOT as worrying as before we knew more facts – such as that the emergency spillway IS on bedrock – and care was taken to get a good bedrock base during construction – making a failure unlikely:
“In part of the emergency spillway, an additional 10 feet of excavation was required to reach acceptable foundation rock, resulting in considerable additional time for excavation and placement of the backfill concrete to subgrade. ”
Further, while there is more than can and should be done – crews gave repaired the major erosion on the ogee spillway bench … with boulders, hardened by cement.
Your claim these repairs are aren’t sufficient is not supported by the facts and evidence.
First, it is exactly these same type repairs, boulders reinforced with cement, that worked flawlessly at the main spillway end of the emergency spillway bench …
Second, the crews oriented these hardened areas following the path flow had already identified as the path it wanted to follow. Where the water chose to flow is what they repaired and hardened.
Third, along with the information they went to extra effort t insure solid, good bedrock for the foundation is that the ogee weir section includes a 12′ apron at the down slope base – that is 6′ thick – and sits on bedrock.
Additionally a high ridge of bedrock sits between the main spillway and the dam … the dam is effectively isolated from the emergency and main spillway …
And yet the exposed bench bedrock just downstream from the weir crumbled, the first time it was exposed to a minor flow, in one spot almost to the weir apron. That wasn’t supposed to happen. When something like that happens, saying “failure unlikely” is premature. The condition of the bedrock under the weir foundation is unknown, and suspect until proven otherwise. As also the weir/bedrock contact plane.
The weathered SURFACE rock eroded.
And we do have a good idea of the condition of the bedrock condition for the ogee weir emergency spillway foundation … the builders went to significant extra time and expense to ensure they were down to high quality bedrock for the foundation. That bedrock foundation is well underground. It is not exposed to weathering.
Scott, I refer in particular to EricL’s Post No. 517, BradP”s No. 523, and Rock Whisperer’s post No. 634, at Metabunk.
Impermeable obstacles created by repairs on the slope side of the emergency spillway will cause the overflow to pool and thereby create concentrated flow points to begin erosion. See your Post No. 660.
Your reference to the main spillway is classic diversion from my point about the parking lot. “Oh look, a squirrel!”
And you could have been much more effective in criticizing the Butte County Sheriff. IMO he made the right call on the evacuation but, if the emergency spillway had failed, hundreds or thousands of people would have unnecessarily died from his emergency management failures.
There was no pre-existing evacuation plan for a reservoir breach.
No hasty evacuation plan was made when the main spillway cratered.
His office did not seem to consult any emergency managers, let alone state OES, when he decided to order evacuation.
We know this because the roads and highways out were not made all one-way to foster the evacuation. I saw incoming traffic using them on television Sunday evening.
Even New Orleans roads were made one way out for the evacuation before Hurricane Katrina.
What you should have done was point this out and suggest that the Sheriff was as professional in ordering the evacuation as he was in managing it.
Tom … I made NO comment on the Sheriff or his actions. You can feel free to denigrate and second guess his decision if you like – as I have been involved in emergency preparedness and management since I was in high school I will not use hindsight and bash someone who made a gigantically important and critical decision and erred on the safe side.
You take the data given, evaluate it to the best of your availability, and make a decision. The Sheriff was told there was erosion rapidly approaching the base of the spillway and failure could occur within 45 minutes.
What would your decision have been?
And what if they were accurate, and you dicked around for 15 or 20 minutes talking to others and people died?
And what if you are completely correct? That everything could have been better. What point does attacking as you suggest, do in any way? Clearly the Sheriff understands everything you brought up. And I guarantee his staff and others are scrambling to develop a plan and procedures.
Context and situation matters.
Everything coming over the next weeks and months is on top of a state that has been saturated unusually early.
Right now, Feb. 15th, snow/water equivalency exceeds the peak April 1st levels.
No public officials anticipated this.
Quite the contrary all of them were confident California was in the middle of a doomish persistent drought produced in part by global warming.
Because of their irrational political belief in a lingering or permanent drought their focus was on containing as much water as possible without any regard for retaining flood control capacities.,
Now the state is in a horrific situation that has little to no flood control options as the natural return to a routine wet cycle unleashes what flood control would control if it had not been sacrificed.
I do not think that this winter can be called a routine wet winter. This is very likely a cyclical flood as was the 1996/97 winter which affected the region from Marin County in California up to central Oregon. Now there is the distinct possibility that there is going to be a step up with this storm moving in as it is holding twice the water weight of any of the previous storms to make landfall. The last several storms ranged from 0.6 kg/m2 to 1.2 kg/m2. Off shore right now is a flow rated at 2.5 kg/m2. That is the biggest flow of the winter to make landfall. …https://earth.nullschool.net/#current/wind/surface/level/overlay=total_cloud_water/orthographic=-151.91,28.34,497/loc=-126.780,37.700
I meant routine as in historically been there done that regardless of how infrequent the that is.
Making things work and run safely and efficiently is some weird fetish of the right. We on the left know that making restrooms safe for everyone regardless of any residual dangly bits is where the real focus needs to be.
one upside to all this rainfall up north?
panning for gold in the various creeks, etc, this summer/fall might pay off handsomely.
they didn’t find all the gold back in the day.
Panning is back breaking. The best way to search is with a metal detector or dredging. Unfortunately the climate nizis shut down the right to dredge 7 years ago. Last year a judge ruled in favor of dredgers after a 6 year battle. Yet the current eco nizi regime still refuses to issue dredge permits. This is for recreational dredging, and despite the fact that the Mining Act of 1872 gives citizens the right to search for gold. But what does a law mean to these folks.
I found this link on cavitation :
https://www.usbr.gov/ssle/damsafety/risk/BestPractices/Chapters/VI-3-20150610.pdf
My background is developing systems requiring extremely high reliability. It seems that this dam given everything that’s been commented on here was designed with multiple levels of safety backup systems – emergency spillway etc.
When a system that has been designed for high reliability fails usually it’s some scenario that wasn’t even considered.
Watching the videos of the high pressure water tear up the concrete spillway made me wonder about cavitation effects.
If high pressure water flows down the emergency spillway we will find out if there is a complete layer of bedrock underlining that area. The cavitation process is a non linear chaotic system and results depend upon the surface which is unknown in the emergency spillway area.
I’ll bet no one in designing this structure considered long periods of cavitation effects in the emergency spillway
From the link cited above:
“For a given discharge, flow depths, velocities and cavitation indices can be determined at key stations along the spillway. The water surface profile program (ZPROF) calculates cavitation indices at identified stations along the spillway, in addition to providing the flow depth and velocity at those stations. This information along with information on offsets and irregularities on the spillway flow surface can be used to estimate probabilities for the development of this potential failure mode.”
Emergency spillways are not “designed” for use. They are a designed weakness in the structure to create a designed failure mode and path. Think of a frost plug for analogue.
A earthen gravity dam WILL fail if overtopped. To avoid using such language the weakest or lowest point is given the name “emergency” spillway. When the dam overtops, the dam HAS failed. The overflow undercuts at the desired point and the reservoir drains. That is how it is “supposed” to work. It is the design feature.
The E- spill doesn’t do much for the people downstream but it DOES save the majority of the main dam and powerhouse. No small achievement – mucho $$$ GK
“I’ll bet no one in designing this structure considered long periods of cavitation effects in the emergency spillway”
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I’ll bet they did, and in fact considered lots of other things.
Which is not to say they’re not sweating things out, like everybody else.
Tom,
The link you provided comes up with a “rejected” page. I would really like to view the info and calculations on that primary spillway. Thanks in advance for any help you may offer.
I like the part at the end of the article where it says “the dam spillway” is damaged.
Does anyone know the velocity of the water in the primary spillway at the current 100,000 cfs discharge? Second question : What is the slope angle of the spillway after the ‘ski jump’ where the spillway turns downward? Accurate answers and supporting links would be appreciated.
‘Moim zdaniem jebnie!’
Jebnie, who’s opinion you’re adhering ?
Allan M.R. MacRae
February 17, 2017 at 2:28 am wrote
otropogo – here is one map of Calgary wells – your thoughts?.
https://calgaryrealestatereview.com/2012/01/12/sweet-oil-sour-gas-wells-locations-in-calgary/
Thanks. No time right now to try the interactive map, but will do so later. I found the comments on the page quite interesting.
In the mid 1980s I moved out of Calgary to the East Kootenay, and my new abode was near a CPR line carrying toxic materials to the Kimberley mine. There had already been a derailment right by the water, and the mayor had been given the bum’s rush by CPRail in his attempts to get prior warning of toxic freight passing through.
I contacted the Calgary Fire Dept. for advice, and was told they had to post sentinels on Scotsman’s Hill overlooking the switching yards to read the warning icons on the sides of the freight cars, as CPR wouldn’t even tell them what dangerous substances they were bringing through Calgary.
When I asked him whether there was an evacuation plan if an earthquake should blow several sour gas wells near the city, he said there was none. “Never mind the wells, there’s a sour gas pipeline running along 36th Ave Southeast, and if that leaks, the gas will flow straight into the downtown bowl and fill it.”
At that time, gas wells were still restricted to a zone at least 2km outside the city, IIRC.
water management but no one never talks about it in politics..