UPDATE: Drone video over spillway added.
Collapse of emergency spillway expected, evacuation ordered
Department of Water Resources officials say they expect the emergency spillway at Oroville Dam to fail, and say residents should evacuate northward.
The emergency spillway suffered erosion and could fail, according to DWR. If that happens, the water behind that barrier will comedown the hill and down the river.
Flow through the broken main spillway was increased to 100,000 cubic feet per second in an effort to lower the water level in the lake more rapidly.
The Butte County Sheriff’s Office reports helicopters will be depositing rock-filled containers to strengthen the potential failure point.
Bud Englund, a public information officer for the incident, said downtown Oroville and low-lying areas, including residents along the Feather River from Oroville to Gridley, are being evacuated.
Reporter Andre Byik said Caltrans and the California Highway Patrol have converted the southbound lanes of Highway 70 into northbound lanes to expedite the evacuation. Traffic there is still nearly gridlocked.
An evacuation center has been set up at the Silver Dollar Fairgrounds in Chico. Black Butte Lake west of Orland has also opened up the Buckhorn Campground to evacuees.
Emergency operations centers as far south of Sacramento have been notified, Englund said.
Evacuation orders have also been made in Yuba and Sutter counties.
From ChicoER.com
My local newspaper publishes a scathing editorial of DWR idiocy and mismanagement
Live video here: https://www.facebook.com/KCRA3/videos/10155026580966514/
UPDATE: DWR issued this statement.n their track record so far…not sure its all that reassuring.
OROVILLE DAM, Calif. – The Department of Water Resources has provided an explanation as to why the mandatory immediate evacuations in Oroville and areas downstream are occurring. The concern is that erosion at the head of the emergency/auxiliary spillway issued evacuation orders for residents. The concern is that erosion at the head of the emergency spillway threatens to undermine the concrete weir and allow large, uncontrolled releases of water from Lake Oroville. Those potential flows could exceed the capacity of downstream channels.
To avert more erosion at the top of the emergency/auxiliary spillway, DWR doubled the flow down its main spillway from 55,000 cubic feet per second (CFS) to 100,000 cfs. The next several hours will be crucial in determining whether the concrete structure at the head of the auxiliary spillway remains intact and prevents larger, uncontrolled flows.
Current flows are contained with downstream channels.
Flow over the auxiliary spillway weir began Saturday morning and has slowed considerably. DWR officials expect that flow to stop entirely soon, according to a press release sent at 6:11 P.M. Sunday. This would reduce the erosion on the downstream side of the structure.
DWR officials stress that Oroville Dam itself is sound and is a separate structure from the emergency/auxiliary spillway.
Source: http://www.water.ca.gov/news/newsreleases/2017/021217-pm_release_oroville_evacuation.pdf
UPDATE: Live view from the State Emergency Operations Center
UPDATE: Drne video shot earlier today:
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https://www.metabunk.org/attachments/e-spillway-parking-contruction-anotated-jpg.24581/
Good photo during construction to give a clear idea of the structure.
That looks like a grand opening ceremony with buses, cars parked and a grand stand with a crowd gathered.
That picture is quite interesting. Look at the area in front of the weir. It has obviously been deliberately planed off. It is mostly greyish except for the circled area where the main erosion took place which is reddish. Now the type of metamorphic rock found in this area is dark grey to greenish grey, but weathers red. This is seen fairly well in the cutting above the main spillway, where the wall is grey with a thin reddish layer at the top. Unweathered rock of this type is very hard and erosion-resistant (“competent” is the technical term), but it weathers fairly quickly, and the weathering products are soft and easily eroded.
The color in front of the weir suggests that it was mostly planed down to or nearly to uneroded bedrock except in the area where the worst erosion occurred.
Interesting site with a lot of information on the geology underlying the dam area.
https://www.metabunk.org/oroville-dam-spillway-failure.t8381/page-6
They say the bedrock is “hard Amphibolite”.
It seems to me that point here really is that water always works against the weakest points first. One place where the bedrock cannot stand up to flow from the emergency spillway is all it will take for a breech with uncontrolled flow.
Looked like the water running over was flowing down a dirt hill side. If that’s what I saw, I don’t think that’s a good thing, that flowing water is going to move that dirt down hill weakening the dam.
There is a thin layer of dirt on top of a metamorphic rock. The erosion you see is the dirt. The rock is not affected.
Look at the photo above to understand the construction. The emergency spillway is not on the dam itself. I think the main concern was that it would weaken its own footing and lead to a collapse of the lip which would lead to a head of several feet to water across the full area of the dam being dumped in very short order into the Feather river.
That is why people were told to run away. The integrity of the dam itself is not in question at this time, othewise they would probably be evacuating S.F. !!
Correct. The emergency spillway sits on top of an natural ridge between the spillway and the mountain. The Emergency spillway itself is a narrow blade of concrete rising 50′ – 75′ into the air.
Note that it is narrow….. This means that the sinkholes that began to form on the front edge of the emergency spillway created a very real risk that this narrow blade of concrete would crumple and collapse. If that happened you would abruptly have the top 50′ – 75′ of the lake dropping down the emergency spillway with no control or hope of regulation.
This is the emergency that has them evacuating everywhere.
Probably not S.F. but definitely Sacramento.
No way for San Francisco, which sits the other side of both a range of hills and the Bay.
All of the low lying lands around the SF Bay would have been flooded. This would have included many of the tech companies, especially those in the low lands of Redwood City. This would have been made worse by the recent full moon. My brother lives in San Rafael, west side of SF Bay. He was saying that his backyard was no longer able to drain water for several days at the peak of the moon and the flows coming into SF Bay.
@goldminor – I have been to San Rafael (I lived in SF for 2 years). It is not much more than a recovered salt water marsh. Even in good times, it has issues.
Yes, that is true enough. This is still the worst that my brother has ever seen in that neighborhood. He has lived there for around 25 years.
And he probably sends his kids to Drake! Tell him they are cannon fodder for Tamalpais 😉
The kids are grown up. My brother sent both of his children to St Ignatius HS in SF. I graduated from there as did my father, and all of his brothers back in the 1930s.
Good non-hysterical report:
https://www.wunderground.com/blog/JeffMasters/more-than-180000-under-evacuation-orders-as-oroville-dam-spillways-co
Hysterical is more exciting though!
Good non-hysterical report
https://www.wunderground.com/blog/JeffMasters/more-than-180000-under-evacuation-orders-as-oroville-dam-spillways-co
I wonder if the anthropogenic global warming idiots in California have figured out that instead of going out of their way to keep coal generated electricity out of their over taxed State that perhaps taking care of the renewable energy that they already had, hydro power, they would have been far better off. To ask these far left fools to use rational thought and reason is not possible when the Obama administration did not consider hydro generated electricity to be renewable energy.
Hydropower does have its critics. And it’s not considered renewable by everyone. It comes with some “pretty significant environmental baggage,” according to John Seebach, senior director of Federal river management with the conservation group, American Rivers. He adds, “The reluctance to call hydropower a renewable energy is based on the impact [it has] on dams on fisheries and water flows.”
May be worthwhile to establish a last ditch opportunity to save the concrete weir in the event of the unthinkable scenario by setting explosive charges on far north side of parking area to establish an emergency “fusible link” that could be opened should a true catastrophe materialize. Blow a 150′ wide region that would erode fairly quickly down to the lower lever of the weir. Charges could be set and timed for different levels/elevation of demolition as required. On another note, they would already be in place for the location of a an additional primary controlled/gated spillway. Great opportunity for pre-construction scouring.
Another contingency would be to have Air Force or National Guard prepare plans and preparation to blow emergency channel from the air. Pre-planning is essential but standby could have a lead time of a couple of days or more. Just need to be ready.
This aerial contingency would only work in a more shallow water level. So … drill baby, drill now!
Total and complete bull$hit. The emergency spillway is in no danger of failing. It is concrete keyed to a good rock. Those will be there long after the soil washes away.
Based on the video from this morning, the soil beneath the main spillway has now been scoured to bedrock, ready to be built up properly to form the foundation for the rebuilt spillway. All for free, gravity and sunlight did the entire job.
Alert: In a stunting revelation Maxine Walters has shown the correlation between moist air being generated by Russia flowing through the Sea of Okhotsk and down to Hawaii forming the pineapple express that threatens to destroy California by washing the Capital of California out to sea. “This is a coordinated effort between Donald Trump and Putin!” senator Walters announced. /s
If you tweet it at her, she will then take it to the floor of the House.
Anthony is experiencing first hand the effects of translocation that can occur through climate change. I wonder though if accommodation would be so forthcoming if the refugees were a different religion or skin colour. I suspect not, given the Trump administration’s treatment of Syrian refugees. Some commentators have suggested that the Syrian civil war was partially attributable to climate change.
Horse puppies. This same potential disaster almost took place 25 months ago.
edit the above:… I meant to say 241 months ago, January 1997.
The main spillway chute may have lifted and ruptured via the venturi effect. The water below the chute is static, while the water above is flowing at a great rate, reducing the pressure. It is the same differential flow that lifts a B747 into the air – 450 tonnes of metal hanging on a very small differential airflow.
Not sure if engineers take the venturi effect lifting the concrete into account – rather than the more ‘logical’ weight pressing downwards. Saw this same thing happening at an airport. The apron was cracking so they laid enormous 2.5 cm thick sheets of steel on them as a temporary measure. A B-757 opened the taps a little to start taxying and it lifted this enormous great sheet of steel as if it was a piece of paper. This was not jet blast getting under the sheet, as the aircraft was above it – this was pure venturi differential pressure, just as you get on the upper surface of a wing.
Any engineers out there know if construction engineers calculate for water venturi ‘suction’?
Ralph
They’d need to deal with the ‘hydraulic jump’ where the flow transitions from laminar to turbulent which is definitely occurring based on the videos I’ve seen. Once the surface starts to break up then you’ll get the transition to turbulent flow which I would expect to greatly increase the erosion.
It would only apply if water with a similar head was also flowing below the spillway. Otherwise it is just a concrete through sitting on a lot of rocks. And putting several meters of water in a concrete through makes it heavier, not lighter.
There could be air or water below. The greater effect would be with water. The water below would be moving slowly enough that it’s velocity would be unimportant.
Not so. The same airport just mentioned also made the turnaround points at the end of the runway out of small bricks. God know why, I thought it a stupid idea when I saw them working.
The first jet that took off tore up all the bricks and made a mess of its tail and of the ILS antenna array. Again, this was not an airflow blowing at the bricks – it was an airflow blowing over the top of the bricks and lifting them up via venturi-suction.
R
I would think that the venturi effect would readily pull up any weakened part of the spillway, if cracks were present.
Bingo.
The flow is supercritical at all points of the raceway until it hits the blocks at the bottom.
Huge lift, huge, really big for sure.
The ogee crown of a spillway takes this into account. It is likely that the designer of the spillway considered that shape in the transition from the flatter portion to the steeper and made the transition flatter than that. It is not likely he considered it otherwise.
It is my offhand thought that the weight of the concrete is likely greater than the venturi effect, but I could be convinced by calculation.
More rain on the way. Get a drilling rig over to the north parking lot and start drilling. Line holes w/ pvc pipe. Set one grid at 15′ depth 100′ width . Set next grid at 30′ depth 100 ‘ width. Set final grid along extreme north along road at 60′ depth and 100’ width.
Whoever is appointed to press the button needs to answer the phone if it rings at 3:00 a.m.
The part of the spillway downstream of the parking lot is keyed 2 Ft into the rock. Damaging the parking lot will accomplish nothing.
I’ve been following https://www.metabunk.org/oroville-dam-spillway-failure.t8381/page-14 the past day or so. Highly recommend if you are really into the Oroville saga. Seems to be cool heads moderating that blog.
Anyways, I’m quite serious about preparing for explosive demolition as may be required (future) as in my comments above. As is the motto of the previously known Boy Scouts, “Be prepared”. I took it seriously.
When the first hole was inspected they should have quickly applied thin steel sheets, drilled into the good concrete, covering the hole. Also, they did not need to leave the spillway closed for 36 hours. And they needed to open the spillway to 100,000 CFS much sooner. Why when 180,000 lives are at risk is no DWR person speaking to the media. That would have created better solutions.
I’m sure that some DWR employee will have a comment for this website, but they will never post their real name. Or if they do they will reveal nothing.
Daniel
One last thought on the drama at the Oroville Dam. Back during the last major rain storm in 1996/97 the turbines were not shut down as there was no danger to the nearby transmission lines. At the same time the peak flow through the main spillway was around 160,000 cfs. That means the peak outflow at that time must have been close to twice the flow which has occurred during this winter’s rain storms.
They were very worried back then because the spillway was flowing at max. The turbines were going full steam. Yet the water behind the dam came very close to going over the emergency spillway. Only the grace of God and the cessation of the rain kept everyone from finding out how weak the emergency spillway was. In light of that I can’t help but wonder why all of the experts could not come to the conclusion that it would be wise to beef up the emergency spillway, and to maintain proper inspection of the main spillway. That was a failure to assess the future risk, imo, as nature had just proven to them that the dam could be overtopped.
Agree Goldminor. Thank you!
Goldminor,
In that case the grids I mentioned in an above should be increased to 200′ widths each. Google Earth shows parking area could handle that increased demolition zone easily. I just checked it before you post your comment and I think it was about 800 ft or so. Anyway a few drilled holes w/ a pvc cap ain’t gonna hurt nuthin’. 😉
The first signs of rain are moving closer. As typical for all of the recent storm tracks they have all arrived earlier then forecast. …http://www.intellicast.com/Local/WxMap.aspx
Not sure how it happened but your link gave me my local radar 4 time zones east of you. Anyway, I needed to check for rain.
It must have been able to find your locale, and then switched the map. Notice though that the main rain is up in Oregon. The fast moving northerly winds might be the saving factor in moving the main storm away from Northern California.
I came across a fairly coherent engineering view of the situation by a dam expert here:
https://youtu.be/rl7Sm15unPQ
I highly recommend the listening to the discussion. I know I learned a good deal.
In addition, I believe the dam expert being interviewed, Scott Cahill, provided some pretty sound advice regarding public communications during emergency situations. I can say, having had been on the management team during two declared national emergencies involving chemical weapons, his approach to public communications is precisely how we handled the public communications.
+10
Great analysis and wisdom! Mr. Cahill rightly wouldn’t commit, but given all he said I wouldn’t return to the evacuated area for at least another week. Already thinking that from reading “Metabunk”, even though Evac’s lifted.
https://www.metabunk.org/oroville-dam-spillway-failure.t8381/
thanks, very informative.
Latest water levels:
Good that they have some room for more water. The rain is passing through the area in which I live, which is around 100 miles to the west and a little north. Although, so far it is a light rain. The Trinity Alps have a great snow cover, along with the surrounding mountains. Snow levels are down to around 3500 feet. Two years ago in February there was zero snow anywhere in the mountains, even on the peaks at 7500+ feet. That was a bit incredible. The Alps used to have glaciers a decade ago.
and the arrogance of mankind
Carl Pope of Eco Watch
‘Now the Feather has shown its strength again. The scariest thing is that once the main spillway failed the emergency spillway began eating out the dam while it was carrying less than 5 percent of its 350,000 cubic feet per second design rating. This strongly suggests that many, perhaps most, of America’s dams, are reliant on engineering assumptions which will not withstand the test of extreme weather unleashed by climate change’.
and the arrogance of Man