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

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

[janetjanet998]

The California Department of Water Resources issued a sudden evacuation order shortly before 5 p.m. Sunday for residents near the Oroville Dam in northern California, warning that the dam’s emergency spillway would fail in the next 60 minutes.

The Oroville Dam is the highest in the nation.

[abb]

Here’s a clean PDF of the whole dwg.

https://lincolnparishnewsonline.files.wordpress.com/2017/03/a-389-4-rev.pdf

[meyer]

I wonder if it’s feasible to use some of the recovered rock debris from below to shore up and add slope to the area under the leading edge of the remaining spillway to give it some chance of survival through the melt season. Otherwise, they’ll surely lose more of it when the next big release comes, and it will threaten the transmission line tower and add more debris. I was thinking of using rock, then grouting/hardening it to provide shoring and a sloping surface to catch the water as it falls.

(It does appear from other photos that they transferred line positions on the towers. There were previously 2 circuits on the lower tower and one on the upper, but a recent picture showed 2 on the upper tower and none on the lower tower).

[meyer]

Interesting information, abb.
Interesting analysis, EarthResearcher

Thanks.

[meyer]

I've noticed, in looking at TVA's Fontana dam, which is a rather tall, large structure itself, that they used an underground spillway. That may present challenges, particularly if it's bored through bedrock, but it would seem to me to be much less affected by heating/cooling issues since the underground temperature remains a lot more steady.

Image of Fontana spilling water...

[janetjanet998]

looks like the stopped leakage on the left side

or did they just divert it with something(white tube looking things at top)?

[meyer]

I don’t know how well those gates seal. They might require the pressure of water on the top side to push them closed tighter (someone else mentioned that). Or maybe they’ve just been working on them to improve the seal. I don’t think it’s necessarily a terrible thing if a little bit of water leaks past.

[janetjanet998]

looks like around 2-3 inches of precip will fall in the drainage basin this weekend..but much of it snow

[janetjanet998]

the leakage was slowly eroding the “hill” directly under the main spillway....you can see the rut marks

[meyer]

the leakage was slowly eroding the “hill” directly under the main spillway....you can see the rut marks

You're right. I was thinking of things in terms of "normal" conditions, but these are hardly normal conditions. When the dropped the flow to 30,000 the other day, the water drop became more vertical and started digging up mud again. That was the context of my earlier statement that maybe they could salvage some of the rocks from the debris pile, along with concrete and grout, to build out the underlying earth below the bottom of the spillway and fortify it for use through the melt season.

Outside of a new solution, they will most likely be using the spillway again because the plant will not be able to move sufficient water to keep the water level at a reasonable level in the reservoir.

[EternalHope]

Very interesting picture and analysis of the visible cracks and the apparent attempt they are making to assess the condition under the spillway. Thank you!

Cracks on the surface, and an “interesting” pattern to the cracks. Lets hope there not voids in the substrate, but the pattern to the cracks certainly raises that possibility.

I wonder if those same cracks were there 2 months ago, and if they have grown since then? Likewise, I wonder if soundings have ever been done before. If so, how do they compare with NOW?

Let’s hope the analysis they are doing this time is correct. So far they have not inspired much confidence.

We already know the main spillway must be used for several months in a row during this year’s spring melt. If their current analysis shows the potential for further failure of the main spillway this spring, then they should be making contingency plans NOW.

If the main spillway reaches the point where it can no longer be used, it certainly seems possible that the “emergency” spillway could handle the whole load either.

So, in a worst case scenario, what are the other options?

I have no direct knowledge of these, but apparently there are two fingers of the lake with some sort of low dam that holds back water when the lake is high. These dams are not ever expected to actually let water out.

Could either of those small dams be intentionally breached instead of using the emergency spillway? There would certainly be downstream damage if they were, but the damage might be less than if the emergency spillway were to fail.

[janetjanet998]

MARCH 3RD

The flood control spillway flows remain at 0 cubic feet per second (cfs). Inflows are approximately
15,000 to 20,000 cfs which has resulted in the lake rising from 845.6 feet to 848.3 feet elevation in
the last 24 hours. Flows to meet fishery requirements are being met by releases through the
Thermalito Diversion Dam and Thermalito Afterbay River Outlet. The total flow to the Feather
River remains at 2500 cfs.
Contractors continue to remove sediment and debris below the spillway. This operation will
continue 24 hours per day. Approximately 168,000 cubic yards of material have been removed
from the debris pile to date.
To prepare Hyatt Powerplant for operation, reconfiguration of the powerlines connecting the plant
to the grid was completed. Work continues on the area below the emergency spillway, access
roads, and various eroded areas created by emergency spillway runoff. Rock benches and check
dams are being constructed to slow water and reduce erosion should the emergency spillway be
required for use again.
For information on lake conditions; including lake levels, inflows, and outflows you can visit the
following website. http://cdec.water.ca.gov/cdecapp/resapp/resDetailOrig.action?resid=ORO
For more information on the Oroville Spillway Incident visit the

[meyer]

Good information, Thanks JJanet. :)

As a power industry guy, I’m pining for return of the generation capability at the Hyatt Power Plant. :)

[Jim W N]

They say the emergency spillway will not be needed, then that it is stable, then that it is about to fail. They say, as they refuse further questions, that they must now go and "protect the people".

These engineers have become well-versed in government-ese. I love engineers. I just hate the government.

Question: Where is the hard accountability?

Government Answer: "Accountability? What accountability? We got no accountability! I dun godda show you no stinkin' accountability!!!!"

Government official respoding to questions.

[janetjanet998]

video released today shot yesterday

notice the workers right below the spillway hanging on ropes for safety starting at 10 seconds

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

just saw on twitter a news conference at noon today local time

[EarthResearcher333]

Hi EternalHope,

I have no direct knowledge of these, but apparently there are two fingers of the lake with some sort of low dam that holds back water when the lake is high. These dams are not ever expected to actually let water out.

Could either of those small dams be intentionally breached instead of using the emergency spillway? There would certainly be downstream damage if they were, but the damage might be less than if the emergency spillway were to fail.

= =

Intentional mini dam breaching: I believe you may be referring to Miner's Ranch Reservoir. There are two parts of this reservoir that have an NW dam (at Oroville lake) and a SE dam that completes the basin for Miner's Ranch Reservoir.

Any intentional breaching of these two reservoir dams, to prevent any further overtopping of the Oroville spillways, would lead to a deep erosion cascade heading towards -for example- North Huncut Creek, and the town of Huncut - IF the initial lake water elevation were high enough at the time of the breachings (above 890ft).

Putting aside the destruction of all of the Miners Ranch Reservoir, the homes, farms, businesses, etc. along the way in this erosion flood, the Oroville dam would force flood waters into this new "mess".

It would be trading one big problem (current challenges at the dam) for a brand new big problem.

Simple answer: The potential damage and flooding would be significant. As to which option results in the best of the worst, that is an answer that emergency contingency planners would have to answer.

RE Cracks: We've been discussing the "cracks" in prior posts. Yes cracks have been present for years prior. As we don't have any official failure analysis information, we don't know the extent of other contributing conditions (voids in the substrate, etc).

Now that the emergency has focused funding and manpower to the issues at hand, we can only hope that Nature will not overwhelm the current dam shortcomings (and temporary fixes).

[meyer]

Flow this hour! Looks suspiciously like a generator is on line.

http://cdec.water.ca.gov/cgi-progs/queryF?ORO

[EarthResearcher333]

Hi Jim, I'm seeking to nudge the "accountability" discussion to a higher plane of awareness. That is, there is a special set of character attributes that leaders (in any position, authority, and in a team) must have in tremendous projects that have such a burden of responsibility to assure safety margins.

I also wish Not disparage good people in a broad brush meme, for you have good people and then you have the ones who choose "otherwise" in all aspects of careers/vocations.

Character attributes: Leaders must be fearless, have heart, build teams, and have trust, and be not afraid to do what is right.

There are many historical lessons that are perfect example studies on how to rise to these levels and achieve success in spite of politics, design oversights then corrections, rigorous testing, endless pursuit of the smallest detail, etc. It is not easy. But you cannot ignore the truths of physics.

Post 1,929.. touched upon a bit of these attributes/qualities (discussion).

A good study: Chief Engineer, Washington Roebling, Brooklyn bridge project. The difficulties, the exceptional work to insure the integrity of the design, budget issues, politics, a shady materials vendor & how it was fixed, etc.

Brooklyn Bridge - Wikipedia

[meyer]

I just watched the noon press conference - at least part of it. They are running 1 generating unit at the Hyatt Power Plant located within the Oroville Dam with plans on having a second unit on line by the end of the day.

The crews are removing approximately 60,000 tons of debris from the river per day, and another 30,000 at night. They are operating 24/7. They are very pleased to have the plant starting to come back, and fully intend to get all of the generation on line to move as much water as possible. He quoted 14,000 cfs.

[EarthResearcher333]

I’ve heard that electrical guys’ nickname “Sparky”...

“Let there be Light”....in the beginning
“Let there be Light”....intelligent planet destroying bomb in B grade sci-fi movie “Dark Star” by a talking smart bomb, just before it blew itself up.
“Let there be Light”... A “Sparky” gives us renewed power at Hyatt..

Between God, a B grade sci-fi movie, and Dam “Sparky” Power/cfs flow restart, I think we have all of the bases covered... :-)

[meyer]

Sparky! Ha! :)