Emergency: California’s Oroville Dam Spillway Near Failure, Evacuations Ordered

Breitbart ^ | Feb 12, 2017 | Joel B. Pollak1

[Repeal The 17th]

I see that, now that you point it out.
Must be a broken drain.

[mrsmith]

“...the work ahead, which is expected to begin after repair plans are finalized within the next two weeks.
the work ahead, which is expected to begin after repair plans are finalized within the next two weeks, Croyle said.
“There are a whole bunch of different options” to repair or replace the main spillway, he said. “Some of them are really interesting.” “
http://www.sfgate.com/bayarea/article/Oroville-dam-operators-forced-to-send-more-water-11009935.php?ipid=articlerecirc

Wow, “finalized within the next two weeks”! I’m impressed.
“ ...“If you have eroded everything that can be eroded, then maybe that’s your new spillway,” he said.”
But I figure they’ll replace the spillway with a bullet water train running straight to the ocean...

[meyer]

“ ...“If you have eroded everything that can be eroded, then maybe that’s your new spillway,” he said.”

Right now, it IS the spillway, or at least 35% of it. :)

I kind of like this guy. I have no idea if he's super-competent, but he has a way with words.

[Repeal The 17th]

The lake level has dropped a foot since they opened the gates.
http://cdec.water.ca.gov/cgi-progs/queryF?ORO

[meyer]

Good. I expect a steady decline in level over the next few days, as long as they can run the spillway. I’m thinking 3 feet a day roughly. Depends on what comes down the rivers feeding into the reservoir.

[KC Burke]

No, no you can’t use my bullet train joke. As I said earlier, if the side canyon gets my new name (Moonbeam Canyon) then I want to backfill that canyon with Bullet Trains -— I expect at least one proper attribution and then you can steal it indefinitely.

LOL

[janetjanet998]

no I’m not so sure..if this video the white that looks like a stream of water is clearly a tube..

https://www.youtube.com/watch?v=dVuOYXOQHp0&feature=youtu.be

the video I posted is after this but is the mist just giving an illusion of water flowing ?or is actual water flowing out it?

[EarthResearcher333]

Large Array of Rock Bolts emplaced to secure spillway Concrete Slabs & a "bypass" drain pipe….

New images reveal a large array of "rock bolts" - that were drilled and emplaced during repair work- that are now observable via the heads of the bolts slightly protruding at the surface of the concrete slabs. Counted 34 bolt locations (circled). These rock bolts will augment the original rock anchor bars within and under the concrete slabs. Notice there is a higher concentration of rock bolts on the Left side of the Spillway. This is within and next to the slab & sidewall that had shifted downslope.

Green drainage pipe has been inserted into the 12" sidewall Drain pipe that became disconnected from erosion of the backfill and/or from the downslope shift of the sidewall. This simple repair "fix" - using the drainage pipe - allows water - if any - from this spillway drain to bypass the backfill area to prevent erosion. In an earlier news clip video, the image resolution mixed with the billowing mist of the spillway waterfall created an illusion that this pipe looked as if water was flowing (light modulation from the mist gave a "waterflow movement illusion to the fixed pipe"). A new video image capture reveals it is just a bypass fix to the damaged/truncated spillway sidewall drain.

..thanks janetjanet998 for tip info & links….

Large Array of Rock Bolts emplaced to secure spillway Concrete Slabs & a "bypass" drain pipe. Notice there is a higher concentration of rock bolts on the Left side of the Spillway. This is within and next to the slab & sidewall that had shifted downslope.

[meyer]

FYI, a few more images added. The first image shows water heading down the spillway from the reservoir end. Note that the side drains are not flowing nearly as much as they had been. I’m not certain as to the level of water flow when this image was taken though.

https://pixel-ca-dwr.photoshelter.com/galleries/C0000OxvlgXg3yfg/G00003YCcmDTx48Y/I0000YvYnqNcZwpw/KG-oroville-repair-20893-03-17-2017-jpg

[EarthResearcher333]

"Note that the side drains are not flowing nearly as much as they had been."

When the spillway was started with a lower flow, the sidewall drains were just faint wet streaks on the sidewall concrete with no discernible flow. However, when the spillway ramped to the higher flow (50,000 cfs), the sidewall drains showed they were dumping water. This implies that all of the repair work of sealing the slab seams and cracks were effective at lower flow rates & pressures but show sign of penetration at the higher flow & pressure of 50,000 cfs (SFgate referred to 50,000cfs to "about 3.2 million pounds of water per second").

So either the repair sealing is ineffective at the high pressure condition or there is a subslab flow source ("piping") reaching the drains. I do not have a comparison photo of the drains while the spillway was operating at 50,000 cfs before the repairs. However, I believe the repairs did help reduce the overall penetration of water underneath the spillway slabs.

No Drain water with lesser spillway flow. Just wet marks on the sidewall concrete.

Drain water flow is observable from the sidewall drains at 50,000cfs. Notice the large mist plume from the higher spillway flow.

[abb]

At first glance, the sidewall drains @ 50K cfs looks quite a bit less than before. It will be interesting to compare it to an earlier pic.

IIRC, there was a period after the failure where they were operating @ 50K cfs for a few days.

[EarthResearcher333]

I'm more interested in the presence of water.

DWR's update stated they fully sealed all of the cracks and seams. If this is accurate, the question becomes - where is the water coming from? Evidence indicates that lower pressure (flows) show a fully sealed chute. However, when the chute is operated at higher pressure (flows), the drain(s) water appears.

1. Is there are a myriad of microfractures that allow migration of water under this higher pressure?

2. Were the repairs inadequate for the higher pressures?

3. Is there a "subsurface piping" flow that rises to the drains under the higher pressure?

4. Whatever the causation the distribution of water in the drains are fairly consistent (i.e. all of the drains are showing waterflow - even if there is a slight imbalance on some). This implies that the causation mechanism either is self balancing (in the subsurface), or is balanced by the presence of the distribution of equal pressure of the chute.

Just discussion queries... time & evidence will likely give clues...

An interesting note: The rock bolts & plates revealed turbulent standing waves when the spillway was ramped up. It will be interesting to see if any cavitation erosion appears at these locations after the spillway is shut down again.

[mad_as_he$$]

I think that the entire remaining spillway parts have been severely damaged. The “West corner” appears to have shifted significantly as you observe. As far as the bolts being driven into the floor, did anyone see a drill rig out in that area(?) or was it just some guys with hand held units. If it was a human held drill process then they are way undersized and probably not deep enough for them to remain anchored for a significant period. I also think they are kidding themselves with the sealant work. Getting good adhesion on concrete even with modern day sealants is tricky at best. The forces involved with that water flow are immense and the sealants are bound to fail sooner rather than later.

The discharge rate of the water at the drain outlets seems to be increasing as time passes. At some flow rate it will do more damage to the supporting ground under the spillway and another breach in the floor will appear.

[janetjanet998]

Juan’s update 3-17 at the bottom of spillway as it was reopened..I wonder how he get can get so close since he isn’t media

https://www.youtube.com/watch?v=kQe0J5NLLT4

[abb]

[mad_as_he$$]

OK, thanks! They have a chance of holding then. We use rock bolts in hard rock mining - overhead. They work well if installed properly and within design limits - of course they don’t have millions of pounds of water adding stress to the surface area.

[meyer]

I’m wondering if they were able to seal effectively near the top of the spillway, given that there was always a small flow of water coming out of the gates. Still, to me, it seems that the water flowing out of the drains is significantly less than it was in the days just prior to shutting it off, when they were maintaining 50,000 cfs.

We’ll see, over the next few days, if the work was effective and sufficient to harden the remaining spillway for the duty of flowing water as necessary. If it makes it through the spring melt, that should be a tribute to the efforts of the engineers, geologists, and workers that scrambled to get this thing under control.

[meyer]

Thanks for posting Juan’s update. He is doing a good job of keeping people informed at a very basic, understandable level.

I believe that he was granted a press pass early on, so he is effectively “the press”.

It is good to see that once the initial “washing” was done and the water was ramped up to the 40,000-50,000 range, the flow is essentially clear coming down the hill. That bodes well for minimizing the debris that will be present when they again shut the spillway down. It’s bound to be less than before simply because they aren’t removing much material now. The bottom flow is essentially in bedrock.

[Jim W N]

Good update. Thanks Janet.

[Repeal The 17th]

From 11:00 yesterday to 11:00 today (local time),
the lake level dropped a little over 4 feet.
(from 864.10 to 860.02)