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:
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
Evacuations ordered.
Mac
Emergency spillway failure any minute!
Here’s a live stream (posted here on WUWT at 6:32 US Pacific Std Time)
Interesting Sherrif decides that the absence of models about what will happen if the emergency spillway goes, is a reason for him to evacuate
Official from Sheriff’s office at press conference said increased flow at primary spillway has eased flow over emergency spillway significantly and it would actually stop sometime tonight.
He also said there was a problem section on the emergency spillway that needs to be addressed and they planned to bring rocks/concrete in to plug some sort of gap when the flow over the emergency spillway ceases.
I haven’t heard anyone address the new rain scheduled to hit later this week.
Kauai just got 9″ in 12 hours. With current winds, it will hit the central California area in 7 days.
The massive outflow now going down what’s left of the primary spillway seems to be going further and further towards the dam shoulder. There is also a massive wall above this section that looks to be something other than solid rock.
I wonder if that wall will collapse and whether it could have any effect on dam integrity…..
Look how much of the mountainside has been blasted out to the right of the spillway. That shows what will happen, if the emergency weir fails times 100.
Damn permanent drought.
It’s a Dam shame.
Here’s the problem point, I think:
http://wermenh.com/images/oro2.jpg
To the right is the emergency spillway (then main spillway, then main part of dam). In the upper left is a parking lot that not only is flooded, but it’s draining down the hillside on the lower left. I assume that is a design flaw of incomprehensible proportions. In the center of the photo the water flowing at the edge of the emergency spillway is likely the concern – there is erosion around the end of the spillway, something that can increase quickly, increasing erosion as it does. People were talking about a failure within an hour, where failure might mean losing some 30 feet of lake level.
They’ve cranked up the outflow of the main spillway a lot, the lake is lowering, the erosion is slower than they expected, so there’s a chance that disaster will be averted.
Nothing is definite. If you live there, get out of there….
Yes that is the problem area Ric.
I saw it early on Sat.:
https://wattsupwiththat.com/2017/02/10/damaged-lake-orovilledam-spillway-being-sacrificed-with-high-releases-now-about-4-feet-to-top/#comment-2423434
Ric, I believe you made a good call on this.
As far as evacuation goes, better safe than sorry with a potential of flooding while the town sleeps.
American engineers are good in cleaning up the mesh.
Dutch engineers are good in preventing the mesh.
It’s a way of living.
That’s why our dikes are designed tot withstand a once in 10000 years extreme whether event.
That’s why we pray:
“Lieve Heer geef ons ons dagelijks brood en af en toe natte voeten.”
“Dear Lord give us our daily bread and once in a while wet feet.”
just to remind us to build better dikes.
My thoughts are with those living beneath the dam.
Just an observation that the technical level of the reporting on the incident has been grade school level, leaving most people with the notion the dam will collapse. I have seen only one decent analysis in a link posted by Wim.
All sorts of video of the emergency spillway obviously NOT collapsing or being undermined at lake level. Then zoom to some undisclosed location where a completely different structure, a concrete retaining wall, has an obvious and dangerous breach and they are dumping riprap in.
In Wim’s link there is bewildered discussion of some location far below the dam. Maybe this is a detention basin intended to buffer emergency spillway release? Personally losing interest until someone who actually knows what they are talking about explains what is going on.
Can someone show me where my reasoning is wrong here?
The water over the ‘Auxiliary’ Spillway dropped because
the water level dopped below 900 feet.
However they cannot stop the damaged spillway to fix it
because water is till flowing in large amounts into the lake from
upstream , which will soon cause the ‘Auxillary’ spillway to start up again
which would make any attempt to work below it dangerous/impossible.
So they need to keep the damaged spillway running.
But on Wednesday a new front, carrying at least as much a load as the one
that started all this, is going to send huge amounts of water into the lake
again.
How I am seeing it is if they keep the damaged spillway going, that may/will
saturate and erode the area in front of the Dam – likely causing the dam to fail.
Alternately they can close it and leave it closed, let all the water go over the
Auxiliary’ spillway, which will collapse and cause severe flooding downstream,
but not catastrophic flooding as it would be if the dam went.
The other worry is that graphs show multiple dams at, near or over rated capacity
all feeding into the same downstream area – that is Sacramento and surrounds.
I am assuming they will (assuming their spillways work), dump all the water they
can which will add to the flooding downstream but save the Dams, and, again, a far
greater catastrophe.
If I lived anywhere from there to LA I would take a hike into the hills or a
late booked sea cruise :\
Thanks for any response – Janice, you are nice – thoughts? 🙂
Aidan
Aidan, Your assessment about the damaged emergency spillway is correct. They are forced to use the primary at all costs to avoid using the secondary as it was the one that was rapidly undermining. Moreover, the primary spillway will have to be in continuous operation for the next few MONTHS as the lake would otherwise overflow via the emergency “spillway” which I think we can see is a misnomer. (at 901′ elv). Most of the lakes volume comes in March. And yes, inflow could exceed outflow and end up filling Lake Oroville again, especially if the primary becomes non-functional due to even further erosion. Furthermore, sediment into the pool below the turbines could render their output useless – another 12,000 cfm gone. As for the dam itself, we disagree. I don’t think it is in any jeopardy due to saturation – it’s capped and built to address that. Bob
“the potential for increased flows in the Feather River of as much as 100,000 cubic feet per second.”
The real potential is for much of the 5 cubic kilometres of water in the lake to suddenly go down the Feather River and surroundings, in about half an hour. They are very lucky that the inflow to the lake has reduced a lot. In the meantime they should keep the spillway flowing as fast as possible in case there’s a storm. And when they rebuild the spillway, put lots of welded steel mesh in the concrete, and about 5 times as much concrete, on proper foundations.
In Feb 1986, the peak Oroville inflow was 266,449 cubic feet per second. Imagine that repeating itself in the near future…. like next week.
Maybe Leonardo di Caprio can spare a helicopter ride or two and pick some folks up?
Anybody know how far down the primary spillway can draw? Can it draw to below 850′? 830′? Thanks a million.
Oh, and also… I heard they can spill to 150,000 cfm… is that true? They’re spilling at 100k cfm now. (Obviously I’m researching their draw-down ability).