Oroville Dam Spillway Failure

Status
Not open for further replies.
I believe this is reference to this debris field shown caught against the FCS gate works
[GALLERY=media, 72]FL_Oroville-2590_02_14_2017 (1) by AlmostaCE posted Feb 20, 2017 at 12:18 PM[/GALLERY]
http://pixel-ca-dwr.photoshelter.co...00NtLpqQZaW.4/FL-Oroville-2590-02-14-2017-jpg

I expect some of this is shown in the photo directly above as "landed" on the bank above the SE intake wall, much has likely been sucked through the FCS as the water level gets closer to the top of the opening.
thanks. should have scrolled back further i guess :) they must have moved it as i dont see anything in the water on the 17th eitehr
17th.JPG
 
Ravines are not exactly geologic features (in the sense of reflecting the type of rock) though are they? They are a function largely of topology from the initial formation of the hillside via uplifting, glacial carving or deposition, or volcanic activity. That's then compounded by the amplifications of essentially random initial rivulets and notches. You'd get ravines even if the hillside were entirely homogeneous (all made of the same stuff).
No disagreement. I appreciate Sushi adding the USGS topological map in post 1203 yesterday. Sushi observed and highlighted a topological feature, and I added a picture showing the same feature.
 
DWR has just released a series of videos showing both the damaged flood control spillway and the erosion below the emergency spillway. They are in reverse chronological order. In #7 & 8 you can see the erosion progression that likely led to the evacuation.


Source: https://www.youtube.com/watch?v=yxgtyOfwrj8&index=1&list=PLeod6x87Tu6eVFnSyEtQeOVbxvSWywPlx


and now with some newly released video from 2/12, you can compare this to the day the weir was flooded over. HD drone footage of the whole area, showing all the flooding!


Source: https://youtu.be/vzcQjvH3idU?t=28s
 
I don't agree with the Bea comment that implies that the trees are there because they are getting water from the spillway. There are trees all over that hillside. I have been going to Lake Oroville and across that spillway for 25 years. In many low water years the spillway is never wet. In the years the spillway is used, trees get plenty of water from rain. The spillway would not be a reliable source for trees to get water. I expect the inspectors recommended removing the trees because their roots could undermine the spill way just as they do sidewalks and driveways.

The other day, I saw from stuff from Bea that I thought about sharing here, but it seemed so inflammatory that I elected to discard it as an unreliable source. I agree with you completely.
 
With so much attention being paid to the 2005 license renewal requests for armoring the emergency spillway, it seems prudent to ask, "If the primary spillway was not damaged, and running within the operational guidelines during the heavy rains leading up to the overtopping of the emergency weir, would the reservoir level have reached El.901?"

Thanks in advance for anybody here would like to undertake that opportunity.
 
interesting example of non-local reporters not knowing what they are talking about. He says he doesnt want to go closer to the river at that time (7:11 in vid)as hes afraid the 'dam' might breach.

He thinks in that situation he'd be safe where he is standing.
The only information in there is confirmation that the public is being blocked from entering the area.
 
With so much attention being paid to the 2005 license renewal requests for armoring the emergency spillway, it seems prudent to ask, "If the primary spillway was not damaged, and running within the operational guidelines during the heavy rains leading up to the overtopping of the emergency weir, would the reservoir level have reached El.901?"

Thanks in advance for anybody here would like to undertake that opportunity.

No, it wouldn't have reached 901.
 
(My first post - please be gentle)


That geologic feature can be seen in this picture. I've drawn an oval where the V-shape from the USGS map can be clearly seen as a ravine.

SITE V ver02 orovilleV.jpg



Welcome Lurajane.

Your image, and the vantage point it contains, helps make the situation a little more clear. I have added some additional annotation.

The red oval with dark red center is located at about the point of initial spillway failure. Since that time the spillway has eroded to include much of the area inside the yellow oblong. The dotted red arrow pointing down to the river overlays an area through which the spillway flow has carved a new erosion outlet.

These features align with the erosion channel you highlighted. I suspect the erosion channel sits where it does because water descending the slope has exploited a weakness in the underlying rock and, over time, created the erosion channel. It is possible, but not yet fully established, that this zone of weakness may have played a role in the original spillway failure. And, once the spillway failed, the unconstrained water further exploited the same zone and carved a new side channel leading to the Feather River.

The overlay in the up-thread post:
https://www.metabunk.org/oroville-dam-spillway-failure.t8381/page-31#post-201689
lies flat against the topography shown on the map. In the real world the subsurface rock is composed of layers which I believe are called bedding planes. These bedding planes may be tilted at angles to the visible surface, and may extend deep below the surface.

The problem with this geographical location is the rock appears to be very mixed. The area around the dam is composed of rock which once formed part of the ocean bed and this rock has been "smooshed" together by later volcanic activity such as that which created Sutter Buttes to the south and Mount Lassen to the north. This unique geologic history is responsible for the gold deposits and placer gold mining activity which gave Oroville its name. It also makes for a geology which is heterogeneous and extremely hard to understand and interpret. This report basically states exactly that:
http://earth.geology.yale.edu/~ajs/1980/ajs_280A_1.pdf/329.pdf
(Thanks to Rock Whisperer for the original link)

In a prior post someone asked for their information to be reviewed by "the experts." Dierdre, one of the site moderators, responded with the question "What experts?" I think that pretty well sums it up. Given the unexpected nature of this event, the unknown geologic factors, and all the people whose welfare depends on this set of structures, there are no experts. In fact I don't think you will find a better source of information on this event than what you will find here on Metabunk and all of the contributors to the site. I have been totally amazed at the quality of information found here and would like to thank Mick and Dierdre and whomever else is responsible.

And thanks for your image. It helps clarify the issue I was attempting to describe.
 
I have very similar looking debris islands in the field behind my house. There's a seasonal creek that runs down the hill that's run about ten times as much as normal and is grinding through the hill. . It has created very similar looking flat topped "islands" of essentially coarse grained sand and mud where the water reaches a flatter area and slows down. Scaling that up I'd expect these "islands" to consist mostly of medium sized stones under a foot in diameter.

I'd take a photo, but it's raining here :)

Also, I live in Shingle Springs, on the same mountain range as the Oroville dam, and on a band of the same metavolcanic rock.

20170220-105008-sxkjv.jpg


So I'm quite familiar with the crumbly brown surface rock, and irregular harder rocks underneath. There's a few boulders left over from construction excavations.

I mention this because it struck me that people's expectations of what happens when water flows over rock or soil will vary greatly depending on their personal experience. That will depend on the local geology, and the local topoloy (and the weather to a degree). Round here it cuts through the brown stuff down to the grey stuff, and it's all jagged. The "ravine" in my field looks like the lower emergency spillway in miniature.

In other regions it just cuts through the grey stuff.

You can see these differences quite starkly in nearby Folsom Lake, which has varied geology.

20170220-110606-gyvu4.jpg



20170220-110737-1oyor.jpg


20170220-110820-u5cbt.jpg



20170220-110859-29pwp.jpg


#3 there is similar geology to Oroville.

So people tend to project their own local experience and expectations onto the situation. It's important to remember this when explaining things to people. Maybe they think of all rock as being like granite.
 
site-v-ver02-orovillev-jpg.25160



Welcome Lurajane.

Your image, and the vantage point it contains, helps make the situation a little more clear. I have added some additional annotation.

The red oval with dark red center is located at about the point of initial spillway failure. Since that time the spillway has eroded to include much of the area inside the yellow oblong. The dotted red arrow pointing down to the river overlays an area through which the spillway flow has carved a new erosion outlet.

Sorry, but this is get back towards the type of long pointless speculation I wanted to keep out of this thread. There's sections of ravines all over the place. This particular one (if you arbitrarily extend it) crosses the ravine 400 feet below the site of the original damage and has to cross a ridge to get there.
20170220-114421-xb54o.jpg


It's needless speculation, and it's cluttering up the thread. Obviously the ground under the spillway varies.
 
Screenshot from that AccuWeather video showing a closer view of the debris island.

Full video just ended live feed. Screenshot taken at about the 2:18 mark:
https://www.facebook.com/AccuWeather/videos/10154965453052889

View attachment 25157
Thanks! I wonder what the river level is at the powerhouse is today? A few days back I saw a post indicating that they had 8' of freeboard, before "flooding" the powerhouse (whatever that means). The debris island certainly appears to be larger than that we saw three days ago, but I recognize the spillway flow is lower so it can be misleading. I also saw an article in the LA Times (dated 3 days ago) that 150,000 cu.yds. of debris have clogged the riverbed, and presumably most needs to be cleared. This number came from the authorities (Mr. Croyle). I wonder what the current estimated debris accumulation is? **link added below**
https://www.google.ca/url?sa=t&rct=j&q=&esrc=s&source=web&cd=4&cad=rja&uact=8&ved=0ahUKEwje66aPvp_SAhVS52MKHSADD1cQFggoMAM&url=http://www.latimes.com/local/california/la-live-updates-oroville-dam-150-000-cubic-yards-of-debris-stand-in-1487367268-htmlstory.html&usg=AFQjCNHWRPOfeyU1DlEmc9kHtv3VwiRk_A&bvm=bv.147448319,d.cGc
 
Last edited:
Press conference
https://www.facebook.com/CADWR/videos/vb.95205192448/10154456135337449/?type=3&theater
  • Storm is no problem, just 5 foot rise anticipated, 110K cfs inflows.
  • Will want to bring outflows to zero soon, so they can remove the debris pile
  • Main spillway has been stable
  • Lots of progress fixing the emergency spillway, still some work to do on priority area.
  • Will continue to fix the e-spillway until there's no immediate chance it will be used, then focus entirely on debris removal
  • Doing a bit of debris pile removal from barges. (Sounds like they don't expect much that way, need the water off)
 
Based on these new photos as well as the panorama you posted above @Mick West , they appear to be constructing a new construction service road down the hillside between the emergency spillway channel and the main spillway.

You can see the beginning in the panorama on the extreme right. My guess is they want a heavy equipment access to the site of the main spillway failure.
 
Press conference
https://www.facebook.com/CADWR/videos/vb.95205192448/10154456135337449/?type=3&theater
  • Storm is no problem, just 5 foot rise anticipated, 110K cfs inflows.
  • Will want to bring outflows to zero soon, so they can remove the debris pile
  • Main spillway has been stable
  • Lots of progress fixing the emergency spillway, still some work to do on priority area.
  • Will continue to fix the e-spillway until there's no immediate chance it will be used, then focus entirely on debris removal
  • Doing a bit of debris pile removal from barges. (Sounds like they don't expect much that way, need the water off)
Just listening to the recording, and one thing was not clear. They plan on going dry in the main spillway for a period of time, and currently the powerplant is not passing water. Do they have a bypass tunnel/channel somewhere to prevent the river drying up? Or will they maintain a small flow down the chute?
 
Just listening to the recording, and one thing was not clear. They plan on going dry in the main spillway for a period of time, and currently the powerplant is not passing water. Do they have a bypass tunnel/channel somewhere to prevent the river drying up?

The stilling pool that the spillway runs into is itself a dammed lake. So they can maintain releases from there into the river.
20170220-130102-40jl5.jpg


It also has a few other inflows from other watersheds
 
The stilling pool that the spillway runs into is itself a dammed lake. So they can maintain releases from there into the river.
View attachment 25232

It also has a few other inflows from other watersheds

There actually are two things they can do downstream with the water, but they have more than enough water in the region already. They can divert to the hydroelectric Thermalito hydroelectric facility.

53843410f471b8c6d2592cab7e3ce0e7.jpg

http://www.water.ca.gov/hlpco/p2100.cfm
 
Sorry, but this is get back towards the type of long pointless speculation I wanted to keep out of this thread. There's sections of ravines all over the place. This particular one (if you arbitrarily extend it) crosses the ravine 400 feet below the site of the original damage and has to cross a ridge to get there.
View attachment 25212

It's needless speculation, and it's cluttering up the thread. Obviously the ground under the spillway varies.

I see no evidence of geologic structure, be it a fault or joints or anything else, that would connect the apparent lineations. Chances are that the viewer is making up in his head something that is not there. A number of comments above reflect a weak understanding of basic geology that I don't have the time or inclination to debunk. I have done research on fault zones and did my graduate work at UCLA so I have seen many lineations in California that really were associated with faults but this doesn't look like one of them.
 
In related news, the similar Don Pedro Dam is using its spillway today

Source: https://twitter.com/TurlockID/status/833818231894794244/video/1


They have a kind of hybrid gated/emergency spillway that drains down the same unlined ravine. Not very steep though.
View attachment 25249

They don't use it much. It runs over a road.

Source: https://twitter.com/TuolumneSheriff/status/833821289223589889/photo/1

Wow. I suspect that road will need some work after they are done... I hope we don't have to start another thread.... (my golf course opens tomorrow in Surrey BC) :)
 
In the real world the subsurface rock is composed of layers which I believe are called bedding planes.
Bedding planes imply original horizontality. Volcanic intrusions such as sheeted dikes are never emplaced horizontally, that would be called a sill, so the correct term here is layer.
 
Bedding planes imply original horizontality. Volcanic intrusions such as sheeted dikes are never emplaced horizontally, that would be called a sill, so the correct term here is layer.

My background is in marine and offshore safety.
When it comes to geology I am truly a true fish out of water.

Would it be accurate to say the ground under the entire site demonstrates a geologic heterogeneity which renders it not readily understandable? The Wikipedia entry on Ophiolite makes extensive use of hypotheses and states "There is yet no consensus on the mechanics of emplacement. " The Wikipedia entry on the California Coast Range Ophiolite states It is arguably the most extensive ophiolite terrane in the United States, and is one of the most studied ophiolites in the North America." Despite this extensive study it does not appear possible to arrive at a general consensus other than to state it is a complex geology and not yet fully understood.

Would that be an accurate lay understanding?

https://en.wikipedia.org/wiki/Ophiolite

https://en.wikipedia.org/wiki/Coast_Range_Ophiolite
 
I've heard mixed reports as to whether the River Valve is functional or not.

At the end of the linked presentation it states that "About 225,000 acre-feet safely released through RVOS (Aug.-Dec., 122 days)". It appears this was in 2014. (RVOS = River Valve Outlet System)
 
Mick, I'm also in the ED county foothills. I have a rock question regarding both spillways:

Just from the photos I've seen, it looks like much of the bedrock now being exposed is what the locals call serpentine and/or greenstone.

Do you agree and also do you know how resistant it is to water erosion compared to other local bedrock?
 
Mick, I'm also in the ED county foothills. I have a rock question regarding both spillways:

Just from the photos I've seen, it looks like much of the bedrock now being exposed is what the locals call serpentine and/or greenstone.

Do you agree and also do you know how resistant it is to water erosion compared to other local bedrock?
External Quote:

Greenstone is a name given to several different types of minerals and rocks.

  • Pounamu, a form of green nephrite jade found in the South Island of New Zealand
  • Chlorastrolite, found in the Keewenaw Peninsula of Michigan and Isle Royale in the US
  • Elvan, a quartz-porphyry found in Cornwall, UK
  • Greensand, glauconite bearing sandstone and a geologic formation in the UK
  • Greenschist, metamorphosed mafic volcanic rock and a metamorphic facies
  • Greenstone (archaeology), a type of stone used by early cultures, particularly in Mesoamerica
  • Greenstone belt, Archean and Proterozoic volcanic–sedimentary rock sequences
External Quote:
Serpentinite is a rock composed of one or more serpentine group minerals. Minerals in this group are formed by serpentinization, a hydration and metamorphic transformation of ultramafic rock from the Earth's mantle. The mineral alteration is particularly important at the sea floor at tectonic plate boundaries. https://en.wikipedia.org/wiki/Serpentinite https://en.wikipedia.org/wiki/Serpentinite
if you scroll up to post #1252 youll see a geological map. you can also look for 'geology' links within this thread, as the rock has been discussed pretty intensively. Theres a brief summary of the thread here, that might help you locate info.
https://www.metabunk.org/oroville-dam-spillway-thread-quick-links.t8416/
 
But this current event is over, so this general thread will be closed down tomorrow (Sunday).


I just want to give sincere thanks to Mick, Deidra and all of the intelligent and learned contributors of the Oroville threads. I live (what the locals colloquially call) “up the hill” from Oroville and my husband drives down into the valley for work. I was very happy to have such an informative and undramatic site to lean on. I found the Metabunk site just before the evacuations started and have since been spending my time (instead of worrying) trying to find drawings, photos, info tidbits and the like for those that would know what they meant. My own way trying to find a way to help in this horrible and helpless situation. I know the thread will be closed soon so I’ll say again before that happens, thanks to all and may all below the dam stay safe.
 
A bit of information I found regarding the question of whether the River Valve is operational:
From a KKTV article posted Feb 17, 2017,
(Source: http://www.abc10.com/news/local/off...epaired-irrelevent-to-flood-control/408738838 )

External Quote:
"An Oroville Dam river valve system damaged in 2009 was repaired about two years ago, and their use wouldn't have made a dent in lake levels during this week's crisis, a Department of Water Resources spokesman said.

The valve system, one of three water release points for the dam, only has the capacity to move 4,000 cubic feet per second, according to a department power point presentation dated February 2015.
The article also mentioned that, although the valve has a capacity of 4,000CFS, "...sustained operation at the moment would be 2,000," said DWR spokesman Ted Thomas."

This is the same valve that was damaged during testing in 2009,
(Source: http://www.abc10.com/mb/news/local/...-fourth-way-to-release-excess-water/408086236 )
and reviewed again in 2012
(Source: http://www.orovillemr.com/general-n...r-valves-blamed-in-2009-oroville-dam-accident ) .

According to the latter article, DWR policy prior to the repairs two years ago was that those valves would not be operated.

Hope this was helpful!
 
Status
Not open for further replies.
Back
Top