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.

[Repeal The 17th]

So now they have to add the potential failure of the bridge over the spillway to their to-do list.

[KC Burke]

Please excuse me if I missed it but do you conclude from what you have seen so far that Gate Replacement will be a feature of the 2017 bid project?

[EarthResearcher333]

"So now they have to add the potential failure of the bridge over the spillway to their to-do list."

I would imagine that the engineering design consideration(s) discussion have been very intense regarding reliable "access" to the ES side & west access to the Main Spillway side. You have multiple factors involved. (1) If they create a major access from the north & west side of the river, this forces a "crossing" of a type in the Emergency Spillway "expected to be damaged" hillside area. (2) Do they risk severe damage to the Flood Control Gate Structure by further heavy & intense use of the spillway bridge. (3) Is the best compromise a new bridge across the upper main spillway...and yes, this creates a "Probable Failure Mode" consideration to the safety of the dam (to which the backup spillway redundancy is the Emergency Spillway)

[EarthResearcher333]

"...do you conclude from what you have seen so far that Gate Replacement will be a feature of the 2017 bid project?"

No. The only Gate Repair that should be done at a minimum is the Anchor Tendons + structural repairs to existing cracks. They don't have enough time to do a "major gate replacement". (assuming this is what your question is asking i.e. Full Radial Gates, Trunnions, Head Structure, or combination thereof etc).

[KC Burke]

Well, California DWR has to have some crisis for 2018 to look forward to in the grasping of Federal Funds and the mantra of Constant Water Crisis.

[EarthResearcher333]

For Clarity: The "Bridge" issue/discussion is regarding the possibility of a separate structure, away from the existing Flood Control Gate structure, somewhere in the elevated ridge area of the upper main spillway. The basis for this deduction is that there likely is a calculated & real risk posed to the existing Flood Control Gate Structure bridge from the existing cracks, recent intense usage, informal reports of other side access cracks (approach) forming, and "one way" usage of the bridge with slow speeds during the recent heavy load transport repairs.

However, this too (bridge) may be a logistical & time consuming project to execute.

In the original construction of the Spillway, there were two land crossings at the elevation of the spillway chute grade before the upper & lower spillway sections were completed. Of course, the Flood Control Structure was not completed at that time and thus there was no bridge available.

Since the Main Spillway needs to be inoperative during the reconstruction & repair, they could use a temporary access road across the erosion canyon exit channel next to the Feather river. This would eliminate the logistics, cost, and time for an upper spillway west access heavy crossing use item (i.e. no separate bridge) alleviating the necessity of using the Flood Control Structure bridge.

[EarthResearcher333]

A few posts back you described a California “Study”. Is this a brain-child idea of political developments specific to California? (i.e. a “Study” to study a “Study”). (I’ve seen some of the California Traffic “Studies” designed for public involvement. It looked to be a very convoluted “feel good” process on top of already existing formal processes). Did I miss anything on your post (i.e. missing if sarcasm..)

[EarthResearcher333]

BTW - I don’t think they (DWR et al) will have nearly the time they expect to do the emergency repairs in 2017. This is going to form a new crisis (if it turns out to be).

[EarthResearcher333]

Oroville Spillway Project May Soon Face another crisis - Unusual Extremes - Unpredictable Weather re: 2017 Repairs

In a Mirrored case of weather "extremes", the Southern Hemisphere may be giving insight into a possible "unpredictability" weather problem for the planning of the Oroville Spillway Repair "window". IF this scenario plays out, California may soon, and unexpectedly, flip to another extreme -> Heat (or initially Heat+Rain).

As Northern California has set an all time record for precipitation, including the snowpack in the Sierra Nevada mountains, from Oct 2016 to Apr 13, 2017, extreme weather events were occurring in the Southern Hemisphere. Record Rains & Extreme Heat (109F for many days in Sydney Australia alone) - during our Fall & Winter, their Spring & Summer have been unexpected in "record" extremes. IF this relatively recent "bell weather" indicator follows (i.e. in the Southern Hemisphere & Northern Hemisphere) the expected moderation of Northern California weather (Western US) may not be as expected. NSW Australia recently had the coldest February in a decade (in the midst of an extreme Summer), with snowfall from an unseasonal cold front out of the Southern Ocean, they immediately went back into their extreme heat wave. Their hot summer created extreme fire danger - and resulting fires - over wide regions. Whether these conditions are reflecting a level of odd variance in the Northern & Southern Hemisphere "jet streams", the pattern matching of opposites is what's unusual.

What the Oroville Spillway Repair project could ill afford is a change in the expected weather moderation pattern entering into spring/summer. IF a variance develops such that the jet stream brings unusual "heat" or "heat+rain" in this typically moderate transition, the spillway would need to operate longer, thus pushing out the construction repair "window". Worst Case, if the "heat" or "heat+rain" is swift and extreme, the damaged spillway may not be operable at safe levels above 40,000 cfs (I believe that this is a run rate that the BOC has determined is safe enough with margins given the known defects in the slab chute design). This scenario would force tough decisions in elevating the main spillway cfs flow in combination with having to use the Emergency Spillway. Downstream to the Emergency Spillway is much of the stored excavation material expected to be used in the construction repairs. Any extensive ES hillside erosion damage downslope could threaten the stockpiles of this material. The subsequent cleanup of the river & erosion damage from any Emergency Spillway operation could close out any effective construction repair "window".

In Engineering Planning, contingencies must be planned and anticipated. These contingencies include the application in possible weather anomalies. DWR should detail their planning such that if any weather anomalies develop, they are not caught off guard in an un-recoverable position.

N. Hemisphere may be facing Record Heat soon… as S. Hemisphere had record heat and now is flipping to record cold…

Deep Snow Excavation from Sierra Nevada Snowfall

Wettest "record breaking" North Sierra Precipitation & Winter snowpack as of April 13, 2017.

Extreme Heat in Southern Hemisphere during CA's record breaking Winter snowpack & precipitation.

Record Spring RAINS preceding Extreme Heat in Southern Hemisphere - IS this what Oroville faces? (Heat+Rain then Heat in Northern Hemisphere).

[KC Burke]

The mention of a Study was sarcastic in that post.

As we know, the California state and DWR people have and will spend literally hundreds of millions on studies instead of improvements.

[Jim W N]

Oroville Dam may be in a slow motion Failure Mode

Yup, we may be seeing a train wreck in slow motion.

I think

1) If the people of California knew about this train wreck in slow motion, I have to believe they'd rise up and crucify the SOB's and demand not only accountability but an immediate, clear, and verifiable corrective action plan that could possibly include starting the whole dam thing all over (pun intended), and

2) If I lived in Oroville or elsewhere below the dam, I'd seriously consider hightailing it out of there and billing the State of California for the cost of the move. Maybe a class-action suit.

Of course, as previously noted, government doesn't have any money, They only have your money. Unless they were able to sue the parties involved personally for negligence (or under "strict liability" which doesn't require negligence).

[Jim W N]

Thanks again EarthResearcher333 for your impeccable reasearch.

"Safety should not be sacrificed for cost."

You know, it is hard for me to imagine that "settlement" could actually be controlled and predicted in an Earth Fill Dam of this monstrous size. I would be surprised if an Earth Fill Dam of this size wouldn't have settlement disparity over time.

So one wonders, if a dam of such huge proportions is required, why an earthen dam versus some kind of appropriate concrete dam? One wonders that if cost is the reason even if not the safest alternative, that such a decision would violate (b) "Safety should not be sacrificed for cost."

[Jim W N]

So the cost of what probably REALLY needs to be done from what I’m gathering from the latest posts, is so astronomical that these government agents and officials will settle for what looks like “at least we’re doing something”.

Politics as usual. The risk of political futures versus the risk to the lives and well-being of many thousands of people downstream.

Corruption from stern to bow is what it looks like to me.

[Jim W N]

...and the hits just keep on coming.

Gotta ask this because it is very much a reasonably potential reality.

What the freak happens of there is an earthquake in the region and how high on the seismic scale could it go to possibly accelerate the potential dam failure that may be already underway?

[KC Burke]

Seismic design has progressed over the decades. Even with seismic considerations in the 1970s, a current design would take benefit of more seismic analysis as well as newer design techniques to accommodate such forces.

On a simple building, seismic understanding and design advances in the last 40 years might cause a footing to triple in size for example.

That being said, there are lakes in California where the dam has been deemed very deficient and the maximum lake level reduced to compensate for the condition. There have even been some dams removed due to this issue. Oroville was not one of them.

The unanalyzed green area caused by some sort of weeping is an issue in this regard. The gates and the worn bridge above them are similar issues.

You can go here:
https://earthquake.usgs.gov/hazards/qfaults/map/#qfaults
which is an interactive map. Allow it to load and the zoom in to the Oroville Lake area. You will see that just south of the dam in the Foothills Fault grouping is a Fault labeled the Cleveland Hill Northern Section fault. Not super large or active but certainly something to be aware of when building the tallest dam in the region.

Will that dam have a nearby earthquake that will damage it? Might not during its service life or there could be one tomorrow. Anytime a lake is full, it is much more subject to the forces of nature working against each other.

I did some of my work near the New Madrid fault. We know it is a monster, but nothing has happened there since it was deserted frontier area. When it went just after 1800, it range church bells in Philadelphia. Much that was built in the surrounding 300 miles in all directions has very poor seismic if it was built before 1980 +/-. Design does not prevent structure damage, it minimizes it in some cases.

[EarthResearcher333]

"You know, it is hard for me to imagine that "settlement" could actually be controlled and predicted in an Earth Fill Dam of this monstrous size. I would be surprised if an Earth Fill Dam of this size wouldn't have settlement disparity over time.

Earth Fill Dams, if monitored & taken care of, are a useful design. The original designers placed 100 monuments over the surfaces of the dam just for this purpose - to take care of it & monitor by measurements.

Settlement is more consistent in a sloped rock canyon with sides that allow conformal compaction. In the case of a steeper slope transition zone in the sloped canyon, care is required to monitor for differential compaction, as the lesser angle slope to the greater angle slope changes the compaction forces.

There are a number of remedial measures & technology in fixing differential compaction related seepage issues (injection of mix of clayey & Bentonite material for example). The safety factor for the thickness of the core at Oroville plus the extra attention to the internal slope angled design of the Zone2 and Zone 3 vertical layers provides excellent support to the plastic Zone 1 vertical core layer. Models of the design were tested in actual seismic acceleration conditions & soils/compaction was confirmed to have a good margin of "Factor of Safety".

What surprises me is that this "historic" or "long standing" issue hasn't been figured out. The last thing you want to happen to an earthen dam is to have a decades old puzzle to become an unwanted surprise.

[EarthResearcher333]

"So the cost of what probably REALLY needs to be done from what I’m gathering from the latest posts, is so astronomical that these government agents and officials will settle for what looks like “at least we’re doing something”."

In researching years of back-&-forth communications between FERC & DWR, often there have been letters from DWR where they've asked FERC for more time. DWR stated that "due to staffing shortages and workloads" they have to prioritize, and will ask to delay a task/response. DWR has a large number of dams and water works structures that they manage. The good news to that is they should have a built up a good expertise & resource pool for the wide variety of needed engineering & maintenance tasks & projects. The bad news is that if this larger organization is cut back in state funding - OR - worse, is shorted of state funding and is managed inefficiently, the organization may be tempted to enter into politics over engineering decisions & tradeoffs.

I'm sure that there are good people in places within their organization. But, the patterns of being shorted in funds, resources, and the oft seeming "political engineering" tradeoff looks to be a root problem. Only after a crisis or near disaster do conditions get funding and resources to affect a problem. But a systemic ingrained problem (all of the above) is most difficult to correct.

The construction boom years in the 1960's of the state's waterworks haven't been met with the appropriate sustained attention in infrastructure funding. Now they are in the hole in dam/waterworks/levees infrastructure by some estimates of $65 billion. Thus, crisis management becomes the norm.

[janetjanet998]

lake level was forecast to be at 860 feet right now with inflow of 25,000

it’s at 862 and inflow 30-40,000..it has fallen less then a foot per day since they reopened the spillway

one more weak-moderate weather system thursday..then a long dry spell

over an inch of rain has fallen at the dam the past couple of days with 2-4 in the mts which is helping to melt the snow and increases runoff

at least that means less snow melt later
but it appears this spill will last longer then the 10-14 days planned

[EarthResearcher333]

LATimes: Serious design, construction and maintenance defects doomed Oroville Dam, report says

New Article: A Failure Investigative Analysis Engineer reported his independent findings to the LA Times on the Oroville Spillway failure. Essentially, stating the same findings here: The weak points in the slabs from the drain emplacement upward into the slab causing thinning. He came to the same identical conclusions posted here on FR.

What is of great heartburn is the DWR spokesperson's commentary-> “We anticipate that their findings will be of interest to dam owners around the world,” Mellon said. “Their investigation is open-ended, and they have a great deal of complex information to analyze. The forensics team is expected to give DWR a plan and schedule soon.”

- - end DWR comment.

Why this is "heartburn" is that dam owners around the world already know what caused Oroville's spillway failure. The free flowing information of blueprints, photos, and discussion on engineering forums have revealed the design flaws, the continual patching, and the "jetting" waterflows from the sidewall drains. It is somewhat irritating to repeatedly state (spokesperson) that "findings will be of interest to dam owners around the world". Honestly, a reporter should go and ask what other dam owners around the world think. DWR would likely not appreciate what would be said (may include outright dismissal of DWR's commentary to even wry humor).

- - Engineer commentary Clips:

"The slab is 15 inches thick in most places, but the pipe is 6 inches in diameter and the bell housing at the end of the pipe is 10.4 inches in diameter, meaning that over the pipe the slab was just 4 to 6 inches thick — not much better than a common sidewalk, Bea said."…"“The spillway failed at its weakest point,” he said."

- -

"The drains play an important function in protecting the spillway. Massive amounts of water move through the ground underneath the spillway, exerting tremendous uplifting force, known as hydraulic jacking"…...“It would disintegrate like potato chips under these hydraulic forces,” Bea said. But even if the drains were working properly, they would not have prevented the failure, Bea said."

- -

BTW- Error in the Article: Their reference of about a third of the way down the spillway (incorrect)… should be about 2/3 of the way down the spillway or 1/3 of the way up the spillway…There are other errors in translation in this article regarding bars between the slabs. This may have been due to a communication understanding between what the engineer stated and what the reporter translated.

Serious design, construction and maintenance defects doomed Oroville Dam, report says

[EarthResearcher333]

DWR Excoriated by Failure Engineering Expert - 78 page Prelim Failure Analysis Report extensively details flaws, issues, and culpability

Full report here: Well worth the read. Excellent work (note: a notable number of pictures w/ notes & graphics I created & posted on FRrepublic made it to the report, with insightful markups of his analysis. I don't mind - that is what I was hoping for - getting the word out. Thank you Robert Bea !. & GOOD JOB to ALL CONTRIBUTORS/POSTERS!!!!).

Very, very damaging to DWR as nothing is left untouched. However this report is good news for the public as Robert Bea reveals exactly what the public needed to hear on this failure, including the implications regarding all of the other DWR managed facilities.

I wonder if DWR spokespeople will now change their standard PR response of "other dam owners around the world" will be interested in DWR's findings?

note: Blue underlining of report pages, my emphasis.

Report finds serious design, construction and maintenance defects at Oroville Dam emergency spillway