The Lake Oroville saga continues, yesterday we wondered if the collapse of the spillway might have been due to missing or substandard REBAR, and many experts weighed it on that topic. It now appears that there was REBAR there, and the failure was likely of a nature of lack of maintenance and age combined. It appears the earth underneath the spillway was compromised, and that led to the collapse of the structure without anything to support it.
Today, it is a race against time and water, as DWR has ramped up outflow to 65,000 cubic feet per second, and in doing so, is sacrificing the damaged spillway in hopes that there will not be an uncontrolled release from the emergency spillway, something that has never happened in the history of the dam. During the super El Niño of 1997-1998, it came within 1 foot of the emergence spillway. Now, given the fact that inflow is still exceeding outflow, and emergency release looks very likely.
Here’s video from yesterday showing the damage and concrete blowing out:
Unfortunately, the last update of data at 11:00AM PST today shows a water surface elevation value of 895.84 feet, or 4.16 feet to the top at the 900 foot mark where the emergency spillway starts to kick in.
The rate of rise has slowed from yesterday, and no new additional rain is expected today, but with afternoon temperatures expected to be above freezing well above 4000 feet, we are going to see snow-meltwater continue to flow in. As of 11 AM, they were letting out 65,029 CFS, but have a staggering inflow of 132,107 CFS, more than double the release rate:
Source: https://cdec.water.ca.gov/cgi-progs/queryF?ORO
What’s more worrying is this graph comparing the 1997/98 super El Niño year to this year:
They’ve got a hockey-stick of storage going on, and much earlier in the water year than 1997/98…and they have a busted spillway.
We’ll update this story as more is known.
Here is a historical video for perspective:
https://www.youtube.com/watch?v=CF4ToIhKEeI
UPDATE1: about an hour ago, officals say they “think” they can avoid the emergency spillway:
OROVILLE
With a break in the weather and increased outflow from Oroville Dam’s heavily damaged spillway, state officials said Friday morning they no longer believe the swollen reservoir will breach the dam’s emergency spillway.
After a grim assessment late Thursday, officials announced Friday morning they think they can avoid using the dam’s emergency spillway, which they’ve been working feverishly to avoid. The emergency structure feeds into an unlined ravine, and the water would propel soil, trees and other debris into the Feather River.
The announcement came after William Croyle, director of the state Department of Water Resources, told reporters Thursday evening that water levels in Lake Oroville could reach the brim sometime Saturday, forcing activation of the emergency spillway. The emergency system, which has never been used, would dump water onto an exposed hillside, dislodging trees and earthen debris into the Feather River and potentially affect communities downstream.
Read more here: http://www.sacbee.com/news/state/california/water-and-drought/article131743014.html#storylink=cpy
UPDATE2:
As of 11PM on 2/10/17, Lake Oroville is now less than a foot from the top and overflow on to the emergency spillway.
Update 3: Oroville water level tops 900 feet, water will start flowing down spillway
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Cavitation can produce dramatic effects. Pages 5 and 6 here talk about a famous failure at Tarbela Dam in 1974.
http://www.engr.colostate.edu/~pierre/ce_old/classes/CIVE%20401/Team%20reports/5%20-%20Cavitation%20-%20Fritz%20Glover%20Griswold.pdf
Talk of rebar prompts my favourite picture of it and a picture of its engineering genius Ove Arup on the finished Regents Park Zoo Penguin Pool ramps in 1934 (when engineers dressed properly, wore hats and smoked pipes).
https://www.vam.ac.uk/articles/engineering-the-penguin-pool-at-london-zoo
Considering those ramps were only supporting their own weight (and a few penguins) that is some serious rebar work! I imagine Ove Arup would be appalled if he could watch the videos at the beginning of this post.
Well the ramps are only 3″ to 6″ thick and not propped so its a pretty impressive bit of work without the help of computers and with the lower concrete and reinforcement strengths back then. The Giraffe House is another favourite at The Zoo. The first picture in the link below shows the ramps well, the Giraffe House is the third picture.
http://londonist.com/2015/07/listed-buildings-and-architecture-at-london-zoo
Emergency spill way constructed in the 60’s and never used before will, after a few days of prep, have to be relied upon for days if not much longer? Is that what the situation is right now?
Water begins to flow over Oroville Dam’s emergency spillway for the first time in history
http://fox40.com/2017/02/11/water-begins-to-flow-over-lake-oroville-dams-emergency-spillway-for-first-time-in-history/
It is the relentlessness, there is no way to stop it.
Now it is gravity stored hydro vs the underlying geologic structures.
Gravity will win eventually, it’s just a matter of how much scouring will occur.
Just by looking at what’s going down I’ll make a prediction:
They’ll abandon the damaged spillway and build a bigger one on the other side of the emergency spillway. That massive new erosion at the lower part of the current spillway is just too scary close to the tallest dam in the United States holding back the second largest reservoir in the state.
https://www.google.com/amp/s/kcra.relaymedia.com/amp/article/water-begins-to-spill-over-oroville-emergency-spillway/8732032
Cool, thanks for the link.
Questions, not a challenge, I’m not an engineer. Why does a spillway need such a long run that is built over fill? Couldn’t the top of the spillway and associated gates be built into the bedrock with no long concrete run at all? Downstream flow would run over bedrock. Thanks in advance for any response.
My guess is that it is cheaper to fill with concrete than to cut bedrock.
At least the bedrock will be jet cleaned ready to repairing the spillway !
Exactly. Drill and epoxy in #18 (2.25″) epoxy coated rebar and make a continuous grid. Then simply pour in concrete. A large heavy aggregate would work best I think.
I’m wondering what officials are thinking with regard to Lake Isabella. The dam on this reservoir is ranked “most dangerous” in the U.S. – the nominal capacity is 590K acre feet but because of weakness in the “Axillary Dam”, the new limit is 350K to 375K AF. At the start of January it was at 95K, it is 296K this morning, 73,000 AF being added in the last 7 days. The outflow has been in the 700 – 1100 CFS range all this time, which is a small fraction of what could be let out. Unless they open the gates the reservoir will reach 350K AF by next weekend.
The inflow has been in the 5000 – 12000 cfs range for the last week. With warm weather next week I don’t thing this is going to decrease much, if at all.
They had 10 years to work on it and did nothing. 10 years of clear skies and a near empty reservoir that they could have dug down below the dam base level and greatly increase the capacity safely, then use the soil for repairs to the damn and increase the base size.
This is so typical of California. A disastrous, incompetent government.
re: “that they could have dug down below the dam base level”
Do you understand that the spillway, that LONG, wide ribbon of concrete, rests on the down-slope of a BIG hill (small mountain) comprised of ROCK?
Oh, I see this comment was addressing another dam or reservoir – never mind.
Perhaps,
Anyway, the job of repairing the Auxiliary Dam was suppose to start this year, The current build up of water just seems to go against the plan.
Acre-feet! In 2017! Unbelievable.
When are you guys going to get a decent system of units.
Acre-feet, English units, whereas hectare-meter SI or “French” units?
How do you feel now?
@_Jim : A hectare metre of water (aka 10,000 m^3) weighs 10,000 metric tons. Without looking anything up or using a calculator can you tell me how much an acre foot of water weighs? Didn’t think so.
Nationalism is a pretty stupid way to choose a unit system.
@_Jim: Actually ignore my comment. It is Sunday and my brain is down for repairs.You thought I was trolling and countertrolled. Fair enough. You guys don’t need me to tell you that your units suck. I’m amazed that you put up with it.
Ian H February 11, 2017 at 5:44 pm
‘Nationalism is a pretty stupid way to choose a unit system.’
Which, of course, ironically, is why Napoleon chose it and why it’s been partially enforced in UK so that selling (straight) bananas by the pound (not kilo) means jail time. When I lived in Germany we used to buy cheese at the market by the ‘pfund’ which was rounded up to 500g.
http://news.bbc.co.uk/1/hi/england/wear/3511428.stm
Ian,
To answer your other question … 10,000 X 1.1 = 11K tons (english or short). [ya, I used K …)
Get back to me when you convince the rest of the world to use base 10 for the most used measurement and longest used measurement system.
Humor not your strong suite?
“Acre-feet! In 2017! Unbelievable”
Whatever,
But if it makes you feel better.
1 AF = 1,238 m^3. Oh wait, depending on YOUR convention that might be 1.250 m^3. But to be clear, one thousand two hundred and thirty eight cubic meters.
Actually I do know how much an AF of water weighs. it takes me about 5 seconds to figure it out…of course in pounds.
And I was in too much of a rush to actually answer the question … 1360 tons (31 X 44)/, but why would anyone care
The DWR website table for Oroville Dam is lacking a column for the volume of water outflowing on the emergency spillway. It never needed one before. The table would be more informative if this column existed.
Simply subtracting the tables outflow from the inflow would seem to give that result at this point. But estimating the inflow based on river height is just a fair guess at high level flows. Measuring output over a weir or through a gate would be much more accurate. So with less than 6″ of water crossing the emergency spillway (weir) I question the inflow number as I doubt that there is over 25,000 cfs flowing over it at this time. I don’t know the length of the overflow on the weir but the pics/video looks like much, much less.
It looks like the lake topped out at 19″ above the emergency spillway at midnight last night. Next weekend might be a different story with the new storm coming.
Dang, but it is fun being an armchair engineer.
News is that water is now flowing down the emergency spillway.
http://www.kcra.com/article/water-begins-to-spill-over-oroville-emergency-spillway/8732032
“Flows over this secondary chute will likely range between 6,000 and 12,000 cfs, the California Department of Water Resources said.”
“Inflows decreased Friday and into Saturday morning to 83,600 cubic feet per second, of 10 a.m., water officials have also decreased outflows from the damaged spillway to 55,000 cfs, according to DWR.”
Either DWR is lying or they got the quotes wrong. Q in = Q out so 83,600 cfs into the lake has to equal the flow out of the lake. 83,600 – 55,000 = 28,600 cfs over the emergency spillway at equilibrium.
It’s not yet in equilibrium. Each hour the new data shows the water level is still rising, indicating the inflow is still outpacing the combined spillway outflows. The emergency spillway volume will therefore keep increasing for a while longer.
“83,600 cfs into the lake has to equal the flow out of the lake. 83,600 – 55,000 = 28,600 cfs over the emergency spillway at equilibrium.”
I’m not a hydrologist so I may be wrong on understanding in/out flows and lake volume. It seems to me that “a has to equal” statement assumes that the lake must be a hard sided container. A better analogy might be a balloon. As a fisherman and boater I’ve seen that, as water rises in a lake, some of the the water gets spread out into all the low areas in the terrain. Sometimes there is great fishing in all the newly flooded stream inlets, flats, and around newly flooded structure as well as pinch points between newly created islands.
Have I missed something?
As soon as the first 6 feet of marina dock is installed, or the first 6 feet of waterfront mansion footing is poured, the purpose of any previously important flood control lake and dam is destroyed.
Hope the emergency spillway doesn’t get undercut.
Here is a great picture showing the scale & details of the Oroville dam, spillway emergency spillway.
It’s no wonder officials are not too worried about the dam itself. It’s immense size is impressive.
Also this appears to be a web cam from above looking at the water going over the emergency spillway.
https://www.parks.ca.gov/?page_id=29411
It’s the tallest dam in the US but the water is right at the edge of the parking lot shown at the bottom left. That’s a lot of water. Now my question is what underlies the surface. Is it bed rock? If so what kind and how porous? The primary spill way is not going to be fixed overnight and thus the emergency spillway will have to be relied upon to for some time to come it seems. I’m no engineer but I have seen what a powerful flow of water can do and how quickly it can erode away seemingly solid substrate. It all seems rather dicey to me.
“The primary spill way is not going to be fixed overnight and thus the emergency spillway will have to be relied upon to for some time to come….”.
That’s an interesting point. As I said above it would not surprise me if they built a new concrete spillway on the north (opposite) side of the current one in relation to the dam, which would also put it on the far side of the emergency spillway. I’m fairly sure they don’t want to undermine that north shoulder of the dam any further. If they really do rebuild the spillway at its current location, that’s going to be one heck of a lot of fill to replace, but then I have no expertise.
As for the emergency spillway being “relied upon” going forward, it can only be relied upon for what it is, a spillway for when the lake maxes out.
After the spring rains, summer flows can be accommodated by the power generation spillway in the dam itself, giving a short time for repairs.
Chris 4692
It is my understanding that this reservoir, like many others there, typically top out at their highest level during the spring thaw. And yet here we are well before that thaw with this emergency spillway being used. This during a year when snow levels in the mountains have been tremendous. With more rain forecast there is a potential that a warm front with rains could result in both rain run off and melt run off from that snow pack making things much worse than they are now. Who knows what is going to happen! But there sure seems to be a potential for a worst case scenario of massive flow over an extended period requiring that emergency spillway to be used a great deal of the time right through spring.
It is obvious already the salmon and smelt numbers in the river are going to take a big hit. Let us hope that is the extent of the damage.
at the top of the picture is the dame . The middle is the main damaged spillway. The field between the parking lot and spillway gates IS the emergency spillway. The bedrock in the hill is likely granite. But I suspect that it is heavily fractured. Over the bedrock soil and loose rock. With water now going over the emergency spillway There is nothing they can do other than watch it. and hope the inflow drops.
You got women on your mind? “at the top of the picture is the dame”
is she pretty? 🙂
I watched a video that stated that the base of the dam is 3500 feet wide, and the length is 6900 feet. That is substantial.
Obviously the early in the water year filling of the reservoir may be a very exacerbating issue if February, March and April produce additionally significant rain and snow.
If overflow on the never tested emergency spillway persists over a long period of time it will be tested big time.
Who da thunk such a problem with so much water would so quickly develop in a state so parched with irreversible drought and a “peak water” crisis?
https://en.wikipedia.org/wiki/Peak_water
Peak water is defined in a 2010 peer-reviewed article in the Proceedings of the National Academy of Sciences by Peter Gleick …….
During the winter of 1996/97 there was a 160,000 cfs going down the spillway in early January
The next 15 day forecast is ominous. Starting Wednesday there could be a week or more of rain. If as much rain falls as I fear, you will see in excess of 150,000 CSS going over the emergency spillway by next weekend. DWR and fake news media are downplaying the seriousness of what is transporting. If worst forecast comes to pass, you could see failure of concrete cap of emergency spillway lip. If that goes, it threatens the regular spillway gates and after that, the dam itself. The power of huge amounts of flowing water can’t be underestimated.
Hopefully temps will stay low enough to avoid the added runoff from washed-away snow.
A few days ago it really warmed up during a heavy part of the storm – it was raining at Mammoth (base lodge 9,200′) – but that didn’t last long, it’s back to 24 degrees at 2pm and snowing (they’ve gotten eight feet since Monday). Right now they look on target to beat the biggest snow year since they began measuring in 1970 which was 668″ in 2010/11 (lowest ever was 94″ in 1976/77).
Well Steve, Thur’s yur problum!
Mike Bentley
Oroville Emergency Spillway activated.
http://www.sacbee.com/news/local/article132154774.html
How NOT to design spillways. See Glen Canyon Dam overflowing.
http://s1307.photobucket.com/user/richholtzin/media/bigwater.jpg.html
http://www.dailykos.com/story/2012/12/29/1173582/-It-Wasn-t-Nice-To-Drown-A-Canyon-Lady-Revisiting-The-Glen-Canyon-Lake-Powell-Rigamarole-Part-III
171,000 dead from Incompetent Central Planning
The Forgotten Legacy of the Banqiao Dam Collapse Eric Fish February 8, 2013
I just noticed a curious thing. This whole adventure got me looking at the surrounding dams on Google Earth and I found that the non-earth dams have been “blacked-out”. There’s a fake structure overlaying where the dam is supposed to be.
Perhaps it’s a Homeland Security thing?
Turn off the 3-D Buildings.
Once again skeptics, who pointed out that California climate is notable for extremes of drought and rain are proven correct. Climate true believers, who encouraged negligent flood control maintenance are proven, once again, to be wrong.
They should heed the scribblings of a homesick school-girl a hundred years ago about another land of fickle climate. She saw the big picture, they don’t
http://www.dorotheamackellar.com.au/archive/mycountry.htm
It’s crazy that an emergency spillway has to be cleared of power lines and vegetation before it can be activated. Proof that they never thought they’d have to use it, just there for ‘regulations’.
re: “to be cleared of power lines”
I think this part just might be bogus; I just reviewed video taken this morning and the HV transmission towers in the vicinity of the main spillway and emergency spillway are still in place.
Were there low voltage ‘distribution’ lines on ‘phone’ poles close in that were removed? Something used to power street lights or other stuff up near the service roads around the spillways?
I saw one video today were they trucked in a buch of boulders and placed them at the bottom of the emergency spillway. Then they poured cement over the boulders. Hopefully the emergency spillway will not erode its foundation.
The emergency spillway via google earth is over 50 ft high. I hope that it maintains its integrity. Also at the far end, it looked like white water forming around the end of the spillway…All they can do now is watch…
The lake is 1 foot above the emergency spillway now.
https://cdec.water.ca.gov/cgi-progs/queryF?ORO
This looks like a recent video
https://ww2.kqed.org/news/2017/02/07/engineers-assess-spillway-problem-at-oroville-dam/
Note: HV transmission tower plainly visible in video.
they left the towers. i saw a news video where they were helicoptering workers onto the towers to disconnect and take down the lines.
The water is pooling behind the access road, they should have bulldozed it before leaving. If the ground is soaked enough there could be a big mudslide that blocks the river below. That is a pretty steep slope.
Is this spill a result of a high reservoir level that would normally be lower? The thinking being drought conditions save the water as it will not rain or snow heavy again. Can Gore be sued if any damage occurs? Brisbane flooding was a result of not lowering the reservoirs enough, also thinking it will not rain heavy ever again.
Oroville reservoir was almost empty last year. Even in drought year to reservoirs reserve some storage volume to minimize flooding down stream. All this was done at Oroville. But it didn’t mater the Lake filled up due to record inflow. From my reading the dame has 2 generators and two diversion tunnels plus the main and emergency spillway. The Lake has been this high since the dame was completed.
DWR status update:
Appears to be a dated video from a day or two ago, given the content.
Also note: They are taking measures to PROTECT the transmission lines, not remove them.
Thanks _Jim. This one appears to be a follow-up. Mentions transmission lines:
According to multiple sources the towers of course are still there but some of the the cables in certain sections have been removed. At a press conference a reporter asked if this would cut power to anyone and they said no, it would just be re-directed between substations.
Well maybe they did remove a couple towers – I just saw this on-line:
OROVILLE — Pacific Gas & Electric crews and contracted helicopter operators to dismantle and remove two transmission towers in the path of an emergency spillway at Oroville dam Friday.
Remember – this hill is strewn with multiple paths of transmission towers so just because you can still see towers and cables does not mean some were not removed.
re: but some of the the cables in certain sections have been removed
“Poles and wires” (quote from the video) do not equate to transmission lines and towers which connect the power plant to the grid. The removed poles were down near the Feather River when the spillway intersects.
harkin1, review the video AJB posted.
re: “OROVILLE — Pacific Gas & Electric crews and contracted helicopter operators to dismantle and remove”
1) Press report, subject to error.
2) The DWR folks, whom I saw with my own eyes and heard with my own ears tell a different story.
3) DWR folks STATE that the power plant MUST be grid-connected in order to ‘discharge’ water via the power plant..
Again, review the video for those details.
Once again, there are multiple power transmission paths leaving the dam. They did not dismantle sections in every path.
And at CNBC:
“Cal Fire crews cleared a hillside area near the dam’s emergency spillway of trees, rocks and other debris to reduce potential debris flows downstream. Crews from the local power company, PG&E, removed several electrical lines and with the help of helicopters moved two transmission towers from the path of the emergency spillway.”
A lot of pressure now on the narrowest part of the dam. Was it 1997/98 last time it was this high? I hope they didn’t forget to maintain that upper part during those 19 years.
IR Ha never been this If I recall correctly it got to 98% capacity. Right now it is probably at 101% or more. This is the first time the emergency spillway has ever been used.
ALTERNATE NAMES: They aren’t calling it the “emergency spillway” anymore. As of this afternoon, they were calling it the “auxiliary spillway”. Somebody with a big salary clearly earned their keep.