Oroville Dam Update

February 16, 2017, 5:42 a.m .PST | self

[keat]

It rained through most of the night in the Oroville area. A storm passed over and is currently dumping rain in the foothills and mountains to the east of the lake. It's a warm storm and can be expected to trigger some snow melt and runoff.

As of 5 a.m. the reservoir level stood at 870 feet, 30 feet below the lip of the emergency berm.

Inflow from the storm should begin late today and max out over the weekend. It remains to be seen whether this will cause the lake to rise dangerously as releases continue at the maximum.

It looks fairly promising and the Pineapple Express doesn't look to have another storm queued up over the Pacific at least for a week.

Temps have risen to 70 degrees in parts of the Central Valley and almond trees are in bloom. It's Spring, albeit a wet one.

[KC Burke]

Carpenters are the foundation of building our world — more ways than one.

[morphing libertarian]

I remember reading that Mulholland was a strong leader in LA building dams for Ventura and LA County and making water right purchases. His efforts opened up the San Fernando Valley to development and essentially made LA what it is today including the current water supply system.

He and an assistant inspected the St. Francis Dam and 1 hours later the dam burst and the final body count was in the hundreds.

Unlike today’s politicians he took public responsibility and resigned.

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

[keat]

Covered pretty well above but I'll add some illustrations.

The Oroville system uses an underground power plant. Water can always be released through this at a maximum rate of 16,850 cfs.

In addition, there is a river bypass that can generally release 5,400 cfs. Pumps can be used when the lake is low to keep the bypass flowing for the hatchery below.

The bottom of the eight spillway gates are at an elevation of 811 ft so they are usable down to that lake elevation and can release a maximum of 150,000 cfs.

With current inflow, they would probably not be able to get the lake level below 811 ft at this time.

The top of the dam is 922 ft. The top of the emergency weir is at 900 ft.

Inflow to the lake has peaked at over 150,000 cfs recently. So the combined release from the dam and bypass, at 22,350 was dwarfed by that. Hence the need for the spillway gates.

The other large reservoir I'm familiar with is Don Pedro with is fairly similar with a dam, three large spillway gates and a concrete weir. We sailed up the the weir on Saturday and the water was about 3 ft from the top of it. They may be playing with fire.

At Don Pedro, there is no concrete spillway channel but it was built a distance from the dam so erosion of the dam during emergency release can't cause erosion issues. I assume geography allowed this arrangement. Immediately next to the gates is a concrete weir that has never overflowed. There is nothing but earth below it.

Here;s a photo below the gates at Don Pedro after the 1997 release. The main road to the south end of the lake and dam was pretty much where the guy was standing. Much downstream flooding occurred. The release scoured a channel down to rock that remains today and would probably help if a future release happened as there is no dirt/trees anymore. The road has been replaced.

Geography probably dictated the proximity of the concrete spillway to the dam at Oroville and the conrete was probably intended to prevent erosion. That all changed when it began to fail.

[morphing libertarian]

1 day later

[palmer]

Thanks for the info. The other outflows are probably relatively small. Personally I think the main spillway is good enough, I can't see it getting rapidly eaten away backwards unless there are hydraulics under it. The emergency spillway is risky with hydraulics right below the concrete weir. One of their motivations for turning off the main spillway last weekend was saving money.

There was a several million dollar hole that started from a 50k crack. That quickly turned into a 100-200m estimate. The stupid people thought they would save money, then there was more warm rain, melt and inflow and they got to test the emergency for the first time during an actual emergency instead of before an emergency (would not have been hard to test in prior rainy years).

[4Liberty]

Livestream of local news station - covers Oroville Dam all day long............

https://livestream.com/KRCR/events/3724366

[KC Burke]

A couple of interesting things about the St Francis break. It went all the way to the ocean and bodies were swept clear out to sea with some recovered on the Mexican border far to the south.

The St. Francis held 1/10th of what Oroville holds.

[Yollopoliuhqui]

Best website for Oroville dam updates, latest photos, technical discussion, diagrams, analyses, etc.:

https://www.metabunk.org/oroville-dam-spillway-failure.t8381/page-18

[rdl6989]

The revised forecast is calling for 10 inches of rain.

http://ktla.com/2017/02/16/10-inches-of-rain-headed-for-oroville-dam-area-revised-storm-forecast-warns/

[The Westerner]

Yes, the Feather was the conduit to SoCal. Had the fathers of the dams and aqueducts been asked to continue building and and the ecofreaks not taken control, there would be smaller reservoirs connected to bigger ones for just these very rainy, snowy winters. The west has always suffered wet/dry cycles along with earthquakes. That's a given. Sorry the environazis won their propaganda campaign that sacrificed brilliant engineering feats to smelt, sea lions, snail darters, and spotted owls.

[The Sons of Liberty]

The Oroville dam is a classic example of what happens when a government becomes so large and bloated that the only thing it accomplishes is its continued existence and ceases to perform its actual function.

I'm curious - Is the Oroville Dam a unique design, or are there possibly several others scattered around that could experience the same problems?

[morphing libertarian]

thanx

[KC Burke]

Dams, bridges, tunnels and highways are something we have learned how to build in the last few centuries but the methods, dangers and techniques are always being updated.

I spent some time involved with large clear-span steel structures. Aircraft hangers and the like. The rigid main frame that spanned 120 feet in 2000 weighted about the same as the one that spanned 60 feet in 1965 and is engineered for more variables with greater weld quality.

Likewise the bridge that failed in Minneapolis would carry the loads but had no redundancy for component or connection failures that would come with age.

There are some dams like Hoover that were in the right spot and really done with ageless design in mind but most aren’t that way.

We now build for seismic conditions everywhere based upon what seismic exposure is from history — few knew of the New Madrid risk in Memphis to St. Louis area in 1950, now every designer does. So even a good design in 1950 isn’t likely to cut the mustard in 2017.

[Nero Germanicus]

California’s budget rainy-day fund is expected to grow to almost $8 billion

Even as his state budget plan detailed the reemergence of a potential deficit in the near future, Gov. Jerry Brown presented lawmakers with a fiscal blueprint that projects the state’s cash reserve will grow to $7.9 billion.

The passage of Proposition 2 in 2014 strengthened the state’s existing rainy-day budget reserve, a savings account first created by voters in 2004. In essence, the new law requires both a larger amount to be set aside each year and the paying of a portion of the state’s long-term debts.

Proposition 2 set the goal of a cash reserve fund that’s 10% of the amount of tax revenues collected that year. The proposed budget would set aside $1.2 billion, bringing the fund to 63% of its mandated target. That’s larger than it was required to grow after Brown and lawmakers agreed to make an extra $2-billion payment last summer.

[Ozark Tom]

Ran across a tidbit concerning a system that tapped into cold water near the bottom of the reservoir, used to manage temperatures of discharged water for the fish population downstream of the dam.

Seems there was an accident leading to a flooding of the control room for this diversion system, a result of malfunctioning equipment. An emergency valve stopped the flooding; but, per the story, the sub-system was never repaired.

[OKSooner]

That doesn’t sound good.

[Ozark Tom]

Neither of these is the lost source of the previous comment; but, add background and detail to the ongoing story—a story which might get hot about next Tuesday once more.

http://www.sacbee.com/news/state/california/water-and-drought/article131941279.html

https://www.peakprosperity.com/podcast/107126/expert-what-need-know-about-oroville-dam-crisis

[Ozark Tom]

Perhaps this is the origin of the anecdote about a valve failure. It describes lots of neglect in certain parts of the dam. A mishap during equipment testing of 72 inch valves in 2009 is described as generating a near vacuum; and, generated a 100 mph wind flow deep within the dam. A five man crew narrowly escaped being sucked into the flow when a neglected steel safety bulkhead collapsed.

http://www.chicoer.com/article/zz/20100223/NEWS/100227917

[KC Burke]

Look up poster Mat_Helm and do an “in forum” search on his posts. He posted about it a few times.

[polymuser]

I posted a link abut the 2009 incident days ago. A flow limiting ring was not installed for the testing of the ‘river valve’, and workers were instructed to open the valve to 100% for the test, also unusual, and workers expressed concerned about doing that. At 85% things fell apart and one worker was hurt badly.

Having a hard time verifying that the river valve control room is or is not still flooded...

https://www.dir.ca.gov/dosh/citations/CA%20Water%20Resources%20313228637Summary.pdf

http://www.abc10.com/news/local/river-valve-damaged-in-2009-could-have-been-fourth-way-to-release-excess-water/408086236

https://www.osha.gov/pls/imis/accidentsearch.accident_detail?id=202489431

http://www.sandiegouniontribune.com/sdut-probe-faults-water-agency-in-oroville-dam-accident-2010feb23-story.html