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First, here’s some Oroville dam math:

Drainage Area = 3,624 sq mi
Maximum Water Surface Area = 15,810 acres or 24.7 square miles.

So, the watershed is 147 times bigger than the maximum area of the lake. So if the soil in the watershed was totally waterlogged and there was no snow and now evaporation, then one inch of rain falling uniformly on the entire watershed would raise the lake (with no outflow) by 147 inches or about 12 feet.

Weather Underground is predicting that the next set of storms will arrive in about 24 hours in the wee hours on Thursday and drop 4.75 inches over the subsequent 8 days. If every bit wound up in the lake, that would raise the lake level, with zero outflow, by 4.75 x 147 or about 700 inches or about 58 feet.

On the other hand, they’ve been able to lower the surface level by at least 8 feet per day (and that’s with not insignificant inflows from the last set of storms). So 8 days times 8 feet per day is 64 feet of outflow.

If all goes well on Wednesday (no rain and the main spillway continues to dump 100,000 cfs), then they’ll start rainy Thursday with the lake maybe 26 or 27 feet below the brim of the no-good emergency spillway. So there is hope of making it through the next ten days without overspilling the brim.

If the main spillway holds up.

On the other hand, it could continue to rain heavily in March and well into April.

For example, here in Los Angeles the biggest rain storm I can recall was 15 inches over

Probably the scariest scenario would be a torrential warm rain that also melts the high altitude snow pack. Those are less common in California, but they do happen.

A more philosophical topic:

A common way to get yourself in trouble in a situation where you have multiple safety systems is to assume the odds of each of them failing are independent.

Say, you have three ways to drain a reservoir:

A. You can run 14,000 cubic feet of water per second through power station

B. You can run 65,000 cfs down the main spillway

C. You can run 250,000 cfs over the grandly named Emergency Spillway.

Say the odds of each one failing is 1/100. Then the odds of all three failing at once are 1/100 times 1/100 times 1/100 or one in a million. No problem!

Except, maybe it doesn’t work that quite like that. Maybe if one fails, the others are more likely to fail.

For example, if the main spillway gets damaged, are you sure you can still vent water through the powerplant?

As far as I can tell, the 14k cfs through the power station under the dam has been shut down for several days now, although I’ve read different explanations for why that is, such as worries about debris from the broken main spillway or too much water going down the main spillway into the river and backing up to the power station

And what if you’ve never actually tested your emergency spillway and the only way you’ll ever test it is if both your other outlets are damaged. Maybe the odds of it failing turn out to be more like 80%? But you’ll only find that out when you’ve got big trouble with the other two drains?

Something similar happened with the financial crash of the previous decade.

You couldn’t lose big on mortgages because, it was assumed, you could model defaults like you model deaths for life insurance actuarial purposes. Defaults happen at random. Right? A wave of defaults would be like a wave of cancer deaths. Not gonna happen.

And if your financial company was national, it couldn’t go wrong betting on the housing market, because home prices have never declined nationally, right? (Of course, what happened is that they went up so high in just four states that when home prices in those 4 Sand States plunged in 2007-08, that was enough to drag the whole country into a recession, which then hurt home prices across the rest of the country).

Oroville really needs a second main spillway, located well away from the current spillway, maybe at the other end of the emergency spillway brim, where the boaters’ parking lot is now.

At Oroville, at the moment, the good news is that the lake is down more than 17 feet below the brim at 901 feet of elevation. That’s 9.2 feet in 24 hours.

A reservoir is shaped like a funnel, so the lower the level falls, the faster the decline gets. So they might get down 10 feet in the next 24 hours.

After that it’s going to start raining again, but it probably takes a few days for the rain to trickle out of the hills into the lake. So if the rains aren’t heavy, they may not top out again over the next week, if the main spillway holds up to the pounding its taking.

The dam is about 21 feet taller at 922 feet above sea level than the 1700 foot wide emergency spillway at 901 feet, so it’s hard to see how the dam could be overtopped, short of some kind of combination of earthquake, landslide and tsunami within the lake.

Overtopping the 901 foot brim of the emergency spillway would likely erode away the base of the 30 foot high lip of the lake they built to hold the lake back.

If that collapsed that would dump about 465,000 acre feet into the Feather River about 750 feet below. That’s about 1/8th the capacity of the reservoir, so it’s a lot less cataclysmic than the dam collapsing.

On the other hand, does anybody really know what would happen from 465,000 acre feet of water plunging 750 feet down. Some of the water might boil back upstream and do who knows what to the downstream side of the dam. So, it could be an important question whether the concrete lip of the emergency spillway would fail over several hours (bad) or all at once (real bad).

A minor issue in this current crisis but one that needs some rethinking is how to manage water levels. Looking at the daily chart for the Oroville Reservoir, it looks like the management was trying to keep the water level at about 850 feet, 51 feet below the brim, even after it started raining on February 2. The maximum they can cut the lake down to intentionally by using the main spillway is about 814 feet, or 87 feet below the brim.

Between February 2 and February 6, about 2.6 inches fell. I don’t know how long it takes for most of the water to get into the lake: I’m guessing maybe 36 hours?

Then on Tuesday, February 7th they discovered the main spillway was damaged. On February 8th and 9th over 3 inches of rain fell on Oroville and the lake peaked at 902 feet on Saturday the 11th. I haven’t looked at old forecasts, but I read something from the Department of Water Resources complaining that the rain was heavier than expected over the watershed.

In retrospect, management should have been spilling water by February 2 or 3 to get ready for the week of storms coming. I don’t know how they get compensated for providing water but presumably they get paid more for having water available in hot dry August than sending it down to the sea white it’s raining in February.

Now this is probably all of a moot point regarding the crisis, because if they had been sending more water down the spillway earlier in February, the spillway would probably have been damaged earlier.

But still, all this suggests that maybe the statistical models for managing outflows are overly oriented, especially after the long drought, toward saving water at the risk of a rare catastrophic failure.

They should probably make it a goal for the rest of 2017 to drain the reservoir down to “ogee crest” of the main spillway at 814 feet of elevation, about 87 feet below the emergency spillway’s brim.

 
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  1. Bruce says:

    If the spillway failed over several hours it might be worth cutting a notch at the top of the dam. This would be risky, since the water might eat through crappy concrete and blow the whole dam. So save it for a last resort.

    Best case, how can they fix this? If everything goes right, will they have to drain the whole reservoir and build a whole new dam?

    Read More
    • Replies: @Steve Sailer
    The dam is, knock on wood, fine.

    If there isn't too much rain, they might get out of this with just a bill for a few hundred million bucks for fixing the main spillway and building a real emergency spillway or maybe a second primary spillway.

    , @AnotherDad

    If the spillway failed over several hours it might be worth cutting a notch at the top of the dam. This would be risky, since the water might eat through crappy concrete and blow the whole dam. So save it for a last resort.
     
    Uh ... no!

    It's an earthfill dam. The one thing you don't want to do if have water running over the dam. That's the whole point of the "emergency spillway" is to have a outlet for overflow that does *not* send water over the top of the dam. (That's the whole point of spillways in general.)

    ~~~

    There are two points here:

    1) The emergency spillway is a genuine design failure--a genuine screwup of us dead white males. (Usually our stuff is pretty awesome and it's the disaster of modernity--letting women and leftists be in charge--that's the problem.)

    I've seen a lot of different spillways of various sorts. But the common element is that you get the water spilling *away* from critical structures. Often even on earthen dams there's a concrete lining on the critical section where water would be moving--potentially quickly--next to the dam structure. This always extends until the water is *away* from the dam and moving mostly *horizontally*. This dam has a concrete lip of 30' or so, creating a lot of force, but then doesn't have the landing area for that water reinforced. Worse the spilled water seems to have a "recollection" path--back near the primary spillway!--which is then subject to serious erosion. If they'd simply poured concrete running a couple hundred feet or so on down from the lip getting the water spread out and running parallel to the ground surface, any erosion would have been minimized and would have been far away from the structure that could be undermined.

    2) As i noted on the previous thread, the big question is what is the character of the rock under the regular spillway. If there's genuine 100 million year old Sierra Nevada granite ... the broken spillway is just dumping a lot of water into a rock canyon. No biggie. You can have it be a permanent feature. But if that hump of hill is just a pile of random aggregate, then blasting your 100,000 cfs down it, could serially eat out underneath the spillway eroding it back and back until you're eating away at the edge of the dam. Then you are in deep shit. It looks like there's a pretty massive piece of good rock in the flow near the break. But what is the rest of it like? With the water, i can't see what's there, what erosion is happening.
    , @Luke Lea

    Best case, how can they fix this? If everything goes right, will they have to drain the whole reservoir and build a whole new dam?
     
    Instead of draining the reservoir, why couldn't they use the existing dam as a coffer and build a new dam on its down-river face?
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  2. @Bruce
    If the spillway failed over several hours it might be worth cutting a notch at the top of the dam. This would be risky, since the water might eat through crappy concrete and blow the whole dam. So save it for a last resort.

    Best case, how can they fix this? If everything goes right, will they have to drain the whole reservoir and build a whole new dam?

    The dam is, knock on wood, fine.

    If there isn’t too much rain, they might get out of this with just a bill for a few hundred million bucks for fixing the main spillway and building a real emergency spillway or maybe a second primary spillway.

    Read More
    • Replies: @Bruce
    'The dam is, knock on wood, fine.

    'they might get out of this with just a bill for a few hundred million bucks for fixing the main spillway and building a real emergency spillway or maybe a second primary spillway.'

    Thanks.
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  3. Probably the best way to calculate the probability that a system will fail is not to look at the components of the system, but rather at the components of the organizations which made it: what are their incentives to cheat?

    One hopes that the civil engineers involved in constructing the dam had fewer incentives to cut corners than the financial engineers behind the housing bubble.

    Read More
    • Replies: @Lot
    The financial engineers still needed willing dumb money customers. The largest ones were large German banks whose government's currency manipulation created excess domestic savings that had no local opportunities to invest. An even more root cause was German demographic decline, lots of German boomers in their peak savings years, not a lot of ambitious young people to borrow that money. Japan has the same issue with excess savings, but the government just borrowed it and spent it on public works projects.
    , @Steve Sailer
    Jerry Brown's dad Pat lowballed the cost of the dam to get it approved. I read somewhere that the full price might have been $20 billion in today's dollars and he sold it to the public as being only $13 billion, or something like that.

    Maybe that's why there's no real second spillway in case the first one breaks.
    , @Hibernian
    Never trust a contractor.
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  4. Lot says:

    Defaults have always come in waves. What was unique about the housing crash was entire large states with double digit declines in a matter of months plus the unprecedented amount of fraud.

    Bubble can be useful, it was the last period in which a lot of housing was built in large CA metros. No ghost cities around here.

    Read More
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  5. Lot says:
    @candid_observer
    Probably the best way to calculate the probability that a system will fail is not to look at the components of the system, but rather at the components of the organizations which made it: what are their incentives to cheat?

    One hopes that the civil engineers involved in constructing the dam had fewer incentives to cut corners than the financial engineers behind the housing bubble.

    The financial engineers still needed willing dumb money customers. The largest ones were large German banks whose government’s currency manipulation created excess domestic savings that had no local opportunities to invest. An even more root cause was German demographic decline, lots of German boomers in their peak savings years, not a lot of ambitious young people to borrow that money. Japan has the same issue with excess savings, but the government just borrowed it and spent it on public works projects.

    Read More
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  6. e says:

    They just announced they are lifting the evacuation order and advising people who choose to return to remain vigilant as things might change again.

    They seem comfortable that the work they’ve done has made the emergency spillway able to withstand another test.

    The forecast for breaks in-between downpours, one other reason they believe they’re in better shape.

    Read More
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  7. Anonymous says: • Disclaimer

    What are the odds of a massive earthquake hitting California and destroying the dam when the next bout of rain hits?

    Read More
    • Replies: @Steve Sailer
    They knew about earthquakes when they built the dam.

    But earthquakes can set off chain reactions like, say, a landslide into the lake causing a tidal wave in the lake. Somebody suggested the Emergency Spillway was designed more with that in mind: it could handle one big wave.

    I'd say they need a second primary spillway, maybe at the far end of the emergency spillway.

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  8. @Anonymous
    What are the odds of a massive earthquake hitting California and destroying the dam when the next bout of rain hits?

    They knew about earthquakes when they built the dam.

    But earthquakes can set off chain reactions like, say, a landslide into the lake causing a tidal wave in the lake. Somebody suggested the Emergency Spillway was designed more with that in mind: it could handle one big wave.

    I’d say they need a second primary spillway, maybe at the far end of the emergency spillway.

    Read More
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  9. Rod1963 says:

    A concrete emergency spillway was recommended over 12 years ago by some enviro groups who saw the flaws in the dirt spillway but was nixed because of cost and no one thinking it would ever be used.

    I love political thinking, it’s so otherworldly and bizarre. Imagine a car designed by the buggers. It would probably be a watermelon with four toy wheels and a $20,000 price tag.

    Read More
    • Replies: @Chris Mallory
    What do you think you are driving Now? Your car was designed by a government committee.
    , @Soviet of Washington
    Did somebody say car designed by politicians?

    https://www.youtube.com/watch?v=rAqPMJFaEdY
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  10. This is a really nice article, Steve.

    I often rant about the lack of numeracy among highly educated people. Your analysis is a v̶e̶r̶y̶ ̶g̶o̶o̶d̶ perfect example of the great insight grade-school math combined with intelligence can yield, when one is trying to understand a current event or the news.

    I’m going to bookmark this and periodically email it to people. Who knows? They may read your other stuff and like it, too.

    Read More
    • Replies: @AndrewR
    Indeed. I've always been pretty good with numbers (I got second place in my district Math Fair in fourth grade and first place in fifth grade in a district with about 400-500 students in my grade), but I do often find it striking just how innumerate even many bright, educated people are.
    , @Steel T Post
    Gateway to iSteve! :)

    "Water can flow, or it can crash; be water, my friend." (Bruce Lee)

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  11. So, this could be simultaneously be a cascading series of disasters as well as a series of cascading disasters?

    Read More
    • LOL: wren
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  12. eah says:

    if the main spillway holds up to the pounding its (sic) taking

    What “pounding”? — looks like normal use to me — a Challenger-like special inquiry is in order to look into the design, construction, and inspection/maintenance of the main spillway — its dramatic failure is a scandal.

    Also the ‘emergency spillway’ — aka a hillside — is a joke.

    Read More
    • Replies: @eah
    And Trump should have told that little shit Jerry Brown to get lost.

    https://twitter.com/vdare/status/831639421342666752
    , @Buck Turgidson
    I have been saying the same. An *independent* review of the decision making process for making infrastructure investments and improvements at California's dams is in order. Hopefully not another 9-11 commission, which was a joke and a farce.

    Yes, calling that emergency outlet a "spillway" is hilarious. You called it exactly what it is, a hillside.

    For a dam of this size?

    How many people are going to get canned? How much will the decision process change?
    , @The Anti-Gnostic
    The main spillway supposedly would have been fine ... if there were two of them. And yes, would also be nice to have a third "emergency spillway" that's an actual ... spillway.

    Two is one, and one is none--what a great saying. Reminds me of "Penny-wise and pound-foolish."
    , @eah
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  13. So we have:

    Top of Dam: 922 feet
    Top of Emergency Spillway: 901 feet

    so what is the level of the Main Spillway: xxx feet?

    This is important since while I assume the Power Plant level is much lower, if they are not able to evacuate water through this path then they cannot lower the lake below the level of the Main Spillway.

    Does anyone know this level?

    Read More
    • Replies: @Steve Sailer
    Good question.

    I found this obscure stat for the main spillway


    Ogee Crest Elevation 813.6 ft msl

    So I think that means the main spillway can drain the lake down about 87 feet below the level of the emergency spillway.

    By the way, the main spillway has a maximum cfs of 150k, 50% more than they are doing at present.

    Here are some other potentially useful facts:

    Table A.2.1-1. Lake Oroville technical data.
    Lake Oroville Specification
    Normal Maximum Water Surface
    Elevation
    900 ft msl
    Normal Minimum Water Surface
    elevation
    640 ft msl
    Drainage Area 3,624 sq mi
    Maximum Storage 3.5 maf
    Usable Storage 2.8 maf
    Maximum Water Surface Area 15,810 acres or 24.7 square miles.

    So, the watershed is 147 times bigger than the maximum area of the lake. So if the soil in the watershed was totally waterlogged and there was no evaporation, then one inch of rain on the watershed would raise the lake (with no outflow) by 147 inches or about 12 feet. So if there are are expected to be, say, 5 inches of rain over the next 8 days and every bit of it wound up in the lake, it would would raise the lake by a little over 60 feet. On the other hand, at 100,000 cfs of outflow they can lower the lake by at least 64 feet over eight days.

    They'll probably start the next set of rainstorms in about 24 hours at about 27 feet below the brim.

    So, they have a decent chance of getting out of February without spilling over the emergency brim, if the main spillway holds up.

    Probably the scariest scenario would be a torrential warm rain that also melts the high altitude snow bank. Those are less common in California, but they do happen.

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  14. eah says:
    @eah
    if the main spillway holds up to the pounding its (sic) taking

    What "pounding"? -- looks like normal use to me -- a Challenger-like special inquiry is in order to look into the design, construction, and inspection/maintenance of the main spillway -- its dramatic failure is a scandal.

    Also the 'emergency spillway' -- aka a hillside -- is a joke.

    And Trump should have told that little shit Jerry Brown to get lost.

    Read More
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  15. This is why Lindbergh chose to fly a single-engine airplane to Paris.

    People thought he was crazy, but he reasoned that the odds of failure would be greater with multiple engines. His idea was risky, but it was right for the engines of his day. Others tried that flight with multi-engined aircraft and were never seen again.

    Charles also said “America First.” He was right about that too.

    http://www.charleslindbergh.com/americanfirst/speech.asp

    Read More
    • Replies: @dearieme
    The first non-stop flight across the Atlantic happened in a plane equipped with two Rolls-Royce Eagle 360 hp engines.

    "Charles also said “America First.” He was right about that too." Not in the context of the first non-stop flight across the Atlantic, he wasn't.

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  16. @Shine a Light
    So we have:

    Top of Dam: 922 feet
    Top of Emergency Spillway: 901 feet

    so what is the level of the Main Spillway: xxx feet?

    This is important since while I assume the Power Plant level is much lower, if they are not able to evacuate water through this path then they cannot lower the lake below the level of the Main Spillway.

    Does anyone know this level?

    Good question.

    I found this obscure stat for the main spillway

    Ogee Crest Elevation 813.6 ft msl

    So I think that means the main spillway can drain the lake down about 87 feet below the level of the emergency spillway.

    By the way, the main spillway has a maximum cfs of 150k, 50% more than they are doing at present.

    Here are some other potentially useful facts:

    Table A.2.1-1. Lake Oroville technical data.
    Lake Oroville Specification
    Normal Maximum Water Surface
    Elevation
    900 ft msl
    Normal Minimum Water Surface
    elevation
    640 ft msl
    Drainage Area 3,624 sq mi
    Maximum Storage 3.5 maf
    Usable Storage 2.8 maf
    Maximum Water Surface Area 15,810 acres or 24.7 square miles.

    So, the watershed is 147 times bigger than the maximum area of the lake. So if the soil in the watershed was totally waterlogged and there was no evaporation, then one inch of rain on the watershed would raise the lake (with no outflow) by 147 inches or about 12 feet. So if there are are expected to be, say, 5 inches of rain over the next 8 days and every bit of it wound up in the lake, it would would raise the lake by a little over 60 feet. On the other hand, at 100,000 cfs of outflow they can lower the lake by at least 64 feet over eight days.

    They’ll probably start the next set of rainstorms in about 24 hours at about 27 feet below the brim.

    So, they have a decent chance of getting out of February without spilling over the emergency brim, if the main spillway holds up.

    Probably the scariest scenario would be a torrential warm rain that also melts the high altitude snow bank. Those are less common in California, but they do happen.

    Read More
    • Replies: @Shine a Light
    Thanks for the main spillway elevation – they have plenty of room to play with.

    The emergency spillway reminds me of the way we design flat roofs in Europe. Typically our flat roofs become a sort of bathtub due to concrete slabs and concrete upstands. But the structure below could never hold the volume of water that would collect if the roof drains ever failed to drain for some reason. So we install “emergency spillways” in the form of cut outs in the concrete parapets in order to ensure the water can never rise above the critical level where the structure below would fail.

    But we don’t really design these cutouts to function properly and water may well leak into the building as they go over these spillways. In fact this is a good thing because this warns the occupants there is a problem up above.

    I wonder how badly the emergency spillway at Oroville failed. What we see is the top soil and other soft soils were immediately eroded away. But surely this was foreseen. The exposed rock looked pretty solid but only an expert analysis would say whether the lip would have eventually failed had even more water poured over.

    If there had been a concrete emergency spillway then maintenance costs would have skyrocketed. This massive additional area of concrete would have settled and cracked as the years went by. It seems the State of California was unable to even maintain the critical main spillway when problems occurred there a couple years ago. Would the added burden of maintaining the emergency spillway have left the main spillway in even worse condition?

    The key to making sure Oroville Dam is safe is to maintain the hell out of the main spillway. And this California failed to do.
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  17. @candid_observer
    Probably the best way to calculate the probability that a system will fail is not to look at the components of the system, but rather at the components of the organizations which made it: what are their incentives to cheat?

    One hopes that the civil engineers involved in constructing the dam had fewer incentives to cut corners than the financial engineers behind the housing bubble.

    Jerry Brown’s dad Pat lowballed the cost of the dam to get it approved. I read somewhere that the full price might have been $20 billion in today’s dollars and he sold it to the public as being only $13 billion, or something like that.

    Maybe that’s why there’s no real second spillway in case the first one breaks.

    Read More
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  18. @Bruce
    If the spillway failed over several hours it might be worth cutting a notch at the top of the dam. This would be risky, since the water might eat through crappy concrete and blow the whole dam. So save it for a last resort.

    Best case, how can they fix this? If everything goes right, will they have to drain the whole reservoir and build a whole new dam?

    If the spillway failed over several hours it might be worth cutting a notch at the top of the dam. This would be risky, since the water might eat through crappy concrete and blow the whole dam. So save it for a last resort.

    Uh … no!

    It’s an earthfill dam. The one thing you don’t want to do if have water running over the dam. That’s the whole point of the “emergency spillway” is to have a outlet for overflow that does *not* send water over the top of the dam. (That’s the whole point of spillways in general.)

    ~~~

    There are two points here:

    1) The emergency spillway is a genuine design failure–a genuine screwup of us dead white males. (Usually our stuff is pretty awesome and it’s the disaster of modernity–letting women and leftists be in charge–that’s the problem.)

    I’ve seen a lot of different spillways of various sorts. But the common element is that you get the water spilling *away* from critical structures. Often even on earthen dams there’s a concrete lining on the critical section where water would be moving–potentially quickly–next to the dam structure. This always extends until the water is *away* from the dam and moving mostly *horizontally*. This dam has a concrete lip of 30′ or so, creating a lot of force, but then doesn’t have the landing area for that water reinforced. Worse the spilled water seems to have a “recollection” path–back near the primary spillway!–which is then subject to serious erosion. If they’d simply poured concrete running a couple hundred feet or so on down from the lip getting the water spread out and running parallel to the ground surface, any erosion would have been minimized and would have been far away from the structure that could be undermined.

    2) As i noted on the previous thread, the big question is what is the character of the rock under the regular spillway. If there’s genuine 100 million year old Sierra Nevada granite … the broken spillway is just dumping a lot of water into a rock canyon. No biggie. You can have it be a permanent feature. But if that hump of hill is just a pile of random aggregate, then blasting your 100,000 cfs down it, could serially eat out underneath the spillway eroding it back and back until you’re eating away at the edge of the dam. Then you are in deep shit. It looks like there’s a pretty massive piece of good rock in the flow near the break. But what is the rest of it like? With the water, i can’t see what’s there, what erosion is happening.

    Read More
    • Replies: @Anonymous Nephew
    "As i noted on the previous thread, the big question is what is the character of the rock under the regular spillway."

    Following this story from the UK, I've waited for someone to ask that vital question at a press conference, and I've not heard it asked. Are journalists all English graduates these days?

    I had a look at wiki btw, and Oroville is the 16th largest dam in the world, by volume of water held back. 4 billion cubic metres of water which IIRC is 4 billion (long) tonnes. But it's dwarfed by the Aswan Dam, which holds back 169 billion cubic metres of water and is presumably the reason why Egypt won't be going to war with Israel ever again. One large missile to that dam and it's goodbye Egypt, save for a few thousand desert Bedouin.
    , @Bruce
    'It's an earthfill dam. The whole point of the spillway is to have water that does not go over the top of the dam.'

    Thanks.

    'The big question is the character of the rock under the regular spillway.'

    If I was dropping boulders from a helicopter into the hole, I'd use wire rope to hold them together. Let the energy of the water go into bouncing the boulders up and down and tangling themselves together, not into bouncing the boulders out of the hole. And I'd bolt wire ropes or I-beams to any visible rock under the spillway.
    , @BDoyle
    The rock under the main spillway is not granite (unfortunately). It's Mesozoic volcanics and meta-volcanics. From the picture I saw from when the spillway was empty, it seems to be a bit less resistant than the concrete itself.
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  19. anon says: • Disclaimer

    True that.

    Systemic risk. The mortgage thing was based on 30 years of data. Or similar. FWIW, in the 1920′s there were various mortgage schemes that weren’t unlike 08. Mortgage bonds and mortgage insurance.

    ‘False Security: The Betrayal Of The American Investor’ by Bernard Reis is a superb overview.

    https://www.amazon.com/gp/offer-listing/1163174017/ref=dp_olp_new?ie=UTF8&condition=new

    Reis, the author, was involved in the Rothko estate scandal.

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  20. @Steve Sailer
    Good question.

    I found this obscure stat for the main spillway


    Ogee Crest Elevation 813.6 ft msl

    So I think that means the main spillway can drain the lake down about 87 feet below the level of the emergency spillway.

    By the way, the main spillway has a maximum cfs of 150k, 50% more than they are doing at present.

    Here are some other potentially useful facts:

    Table A.2.1-1. Lake Oroville technical data.
    Lake Oroville Specification
    Normal Maximum Water Surface
    Elevation
    900 ft msl
    Normal Minimum Water Surface
    elevation
    640 ft msl
    Drainage Area 3,624 sq mi
    Maximum Storage 3.5 maf
    Usable Storage 2.8 maf
    Maximum Water Surface Area 15,810 acres or 24.7 square miles.

    So, the watershed is 147 times bigger than the maximum area of the lake. So if the soil in the watershed was totally waterlogged and there was no evaporation, then one inch of rain on the watershed would raise the lake (with no outflow) by 147 inches or about 12 feet. So if there are are expected to be, say, 5 inches of rain over the next 8 days and every bit of it wound up in the lake, it would would raise the lake by a little over 60 feet. On the other hand, at 100,000 cfs of outflow they can lower the lake by at least 64 feet over eight days.

    They'll probably start the next set of rainstorms in about 24 hours at about 27 feet below the brim.

    So, they have a decent chance of getting out of February without spilling over the emergency brim, if the main spillway holds up.

    Probably the scariest scenario would be a torrential warm rain that also melts the high altitude snow bank. Those are less common in California, but they do happen.

    Thanks for the main spillway elevation – they have plenty of room to play with.

    The emergency spillway reminds me of the way we design flat roofs in Europe. Typically our flat roofs become a sort of bathtub due to concrete slabs and concrete upstands. But the structure below could never hold the volume of water that would collect if the roof drains ever failed to drain for some reason. So we install “emergency spillways” in the form of cut outs in the concrete parapets in order to ensure the water can never rise above the critical level where the structure below would fail.

    But we don’t really design these cutouts to function properly and water may well leak into the building as they go over these spillways. In fact this is a good thing because this warns the occupants there is a problem up above.

    I wonder how badly the emergency spillway at Oroville failed. What we see is the top soil and other soft soils were immediately eroded away. But surely this was foreseen. The exposed rock looked pretty solid but only an expert analysis would say whether the lip would have eventually failed had even more water poured over.

    If there had been a concrete emergency spillway then maintenance costs would have skyrocketed. This massive additional area of concrete would have settled and cracked as the years went by. It seems the State of California was unable to even maintain the critical main spillway when problems occurred there a couple years ago. Would the added burden of maintaining the emergency spillway have left the main spillway in even worse condition?

    The key to making sure Oroville Dam is safe is to maintain the hell out of the main spillway. And this California failed to do.

    Read More
    • Agree: Travis
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  21. AndrewR says:
    @PiltdownMan
    This is a really nice article, Steve.

    I often rant about the lack of numeracy among highly educated people. Your analysis is a v̶e̶r̶y̶ ̶g̶o̶o̶d̶ perfect example of the great insight grade-school math combined with intelligence can yield, when one is trying to understand a current event or the news.

    I'm going to bookmark this and periodically email it to people. Who knows? They may read your other stuff and like it, too.

    Indeed. I’ve always been pretty good with numbers (I got second place in my district Math Fair in fourth grade and first place in fifth grade in a district with about 400-500 students in my grade), but I do often find it striking just how innumerate even many bright, educated people are.

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  22. Luke Lea says:
    @Bruce
    If the spillway failed over several hours it might be worth cutting a notch at the top of the dam. This would be risky, since the water might eat through crappy concrete and blow the whole dam. So save it for a last resort.

    Best case, how can they fix this? If everything goes right, will they have to drain the whole reservoir and build a whole new dam?

    Best case, how can they fix this? If everything goes right, will they have to drain the whole reservoir and build a whole new dam?

    Instead of draining the reservoir, why couldn’t they use the existing dam as a coffer and build a new dam on its down-river face?

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  23. Something similar happened with the financial crash of the previous decade

    .

    I think I’ve never seen before, that somebody uses the example of the last financial desaster to explain something else.

    A little bit baffeld (no – enjoyed, really – maybe quite like Piltdownman in No. 10 above).

    (( And I’m of ourse reminded of Gerd Gigerenzer’s work: Understanding risk)).

    Read More
    • Replies: @dearieme
    "Gerd Gigerenzer’s work: Understanding risk": excellent book. Damn near everyone ought to read it.
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  24. unit472 says:

    There used to be an earthen dam at the Straits of Gibraltar. The Atlantic Ocean did not ‘overtop’ this natural dam but found a way through it. The relevant number is 2.31! That is how much psi pressure a column of water exerts. You divide the depth of the water by 2.31 and you get the psi. So a 900 foot deep lake will exert 389 psi at the bottom . That is why those ravines on the backside of the emergency spillway are so worrying. Should lake water find a path UNDER the concrete lip of the emergency spill way its game over. A jet of high pressure water would shoot out somewhere on the back of that hillside and the lake level would drop to that point in a few hours.

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  25. bjdubbs says:

    Get some pipes and some pumps and that should do it. Of course it might be more complicated than that but it’s not clear why. The water draining over the lip isn’t going at a huge rate, I’m sure pumps & pipe can probably do it faster.

    Read More
    • Replies: @Jack Highlands
    The world's highest capacity pump cost half a billion, took years to build and install, and moves water at one quarter the rate going down the main spillway at Oroville as I type. I assume the idea touted by others here of multiple siphons is more feasible, but I'm skeptical of that too.

    http://gizmodo.com/5800072/the-worlds-largest-water-pump-moves-15-olympic-sized-swimming-pools-every-minute

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  26. They must be very confident the main spillway’s not retreating back up the hill towards the gates (IMHO there was some retreat between Sunday and Monday, but couldn’t see any between Monday and Tuesday, when it had been hammering 99,000 cft/s for 24 hours).

    http://touch.latimes.com/#section/-1/article/p2p-92579161/

    “The pace of the water’s release is “reasonable and sustainable,” said Butte County Sheriff Kory Honea .. Honea said use of the emergency spillway, while brief, allowed enough time for engineers to inspect the main spillway. Engineers were able to confirm that there was no additional erosion, or “piping,” that threatened the integrity of the main spillway.”

    On the other hand, 99,000 cft/s is an awful lot of water, pounding away for what may well be months. Worth keeping an eye on the daily photos/videos.

    Where is Steve getting his figures for dam power output? Can’t find live data with a quick google, athough google’s not what it was 10 years ago.

    It’s an interesting mathematical/logistical problem

    How long will it take to completely repair and strengthen the main spillway?

    How long can they go without using the main spillway? Which to some extent depends on

    How low can they get the water in the dam? I’m presuming (though I don’t know) that the power tunnel is pretty near the bottom, if it uses part of the original diversion tunnel. How does summer input from the rivers compare with the (12,000 cft/s? or 18?) power usage?

    (Tried to answer this, but can’t quite work out what the CDEC figures mean – if you go back to last August, when the level was still at 793 ft, inflow figures are negative. Water doesn’t flow uphill, so what on earth does that mean? Does it net out evaporation? Alas no detail on the data that I can find. And do outflows include both spillways and power tunnels? I’d presume so.)

    Elsewhere in the LA Times they report 1200 tons of rock and concrete slurry per hour going into the emergency spillway, which seems something like the scale needed – other reports say the helicopters move 30 tons/hr, which is a drop in the ocean.

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  27. @AnotherDad

    If the spillway failed over several hours it might be worth cutting a notch at the top of the dam. This would be risky, since the water might eat through crappy concrete and blow the whole dam. So save it for a last resort.
     
    Uh ... no!

    It's an earthfill dam. The one thing you don't want to do if have water running over the dam. That's the whole point of the "emergency spillway" is to have a outlet for overflow that does *not* send water over the top of the dam. (That's the whole point of spillways in general.)

    ~~~

    There are two points here:

    1) The emergency spillway is a genuine design failure--a genuine screwup of us dead white males. (Usually our stuff is pretty awesome and it's the disaster of modernity--letting women and leftists be in charge--that's the problem.)

    I've seen a lot of different spillways of various sorts. But the common element is that you get the water spilling *away* from critical structures. Often even on earthen dams there's a concrete lining on the critical section where water would be moving--potentially quickly--next to the dam structure. This always extends until the water is *away* from the dam and moving mostly *horizontally*. This dam has a concrete lip of 30' or so, creating a lot of force, but then doesn't have the landing area for that water reinforced. Worse the spilled water seems to have a "recollection" path--back near the primary spillway!--which is then subject to serious erosion. If they'd simply poured concrete running a couple hundred feet or so on down from the lip getting the water spread out and running parallel to the ground surface, any erosion would have been minimized and would have been far away from the structure that could be undermined.

    2) As i noted on the previous thread, the big question is what is the character of the rock under the regular spillway. If there's genuine 100 million year old Sierra Nevada granite ... the broken spillway is just dumping a lot of water into a rock canyon. No biggie. You can have it be a permanent feature. But if that hump of hill is just a pile of random aggregate, then blasting your 100,000 cfs down it, could serially eat out underneath the spillway eroding it back and back until you're eating away at the edge of the dam. Then you are in deep shit. It looks like there's a pretty massive piece of good rock in the flow near the break. But what is the rest of it like? With the water, i can't see what's there, what erosion is happening.

    “As i noted on the previous thread, the big question is what is the character of the rock under the regular spillway.”

    Following this story from the UK, I’ve waited for someone to ask that vital question at a press conference, and I’ve not heard it asked. Are journalists all English graduates these days?

    I had a look at wiki btw, and Oroville is the 16th largest dam in the world, by volume of water held back. 4 billion cubic metres of water which IIRC is 4 billion (long) tonnes. But it’s dwarfed by the Aswan Dam, which holds back 169 billion cubic metres of water and is presumably the reason why Egypt won’t be going to war with Israel ever again. One large missile to that dam and it’s goodbye Egypt, save for a few thousand desert Bedouin.

    Read More
    • Replies: @Almost Missouri

    "Are journalists all English graduates these days?"
     
    Worse: Journalism graduates. English graduates might have accidentally read some literature. The whole point of Journalism School is to produce mindless adherence to The Narrative. Independent thought and even just curiosity are ruthlessly exterminated.
    , @Anonym
    Following this story from the UK, I’ve waited for someone to ask that vital question at a press conference, and I’ve not heard it asked. Are journalists all English graduates these days?

    This is a definite problem. Journalism is a destination sought by people who enjoy writing but can't get something that will pay better. If they had some logical or argumentative skill, they might do law. If they had mathematical skill, then engineering, business, management or medicine would be a more lucrative and secure option.

    It is a bit like the occupation of "driver" as mentioned by Steve before. People become drivers not because they have driving aptitude, but because they suck at everything else so bad that their comparative advantage is in driving. So it is with a lot of journalists. They can at least write somewhat entertainingly.

    Since the 1990s the internet has been slowly and steadily drinking the milkshake of the press and visual media. Jobs have been shrinking. You might get a few people who are so very good at writing that they go into the field, but most smart people would avoid it. Look at the people who have made it as bloggers. Our host, a national merit scholar. Glenn Reynolds, a law professor. Pro blogging makes New York look like a small flyover town, in terms of "making it". So my guess is that they would make it as journalists or opinion writers (at least, if Steve stopped noticing he would be employable). Everyone else, not so much.
    , @Almost Missouri

    "One large missile to that dam and it’s goodbye Egypt"
     
    Well, perhaps--if the missile is nuclear tipped. The Aswan Dam is a pretty thick embankment. You'd need a lot of conventional explosives to get through that.

    http://stranymira.com/uploads/posts/2008-07/1217076423_egypt.jpg

    Of course, the Israelis do have that (nukes, that is (as well as lots of conventionals.))

    It's been said that Israel is a "one nuke country" because it is so small, but it is less noted that Egypt may be a one nuke country as well, but for different reasons.
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  28. dearieme says:
    @Buzz Mohawk
    This is why Lindbergh chose to fly a single-engine airplane to Paris.

    People thought he was crazy, but he reasoned that the odds of failure would be greater with multiple engines. His idea was risky, but it was right for the engines of his day. Others tried that flight with multi-engined aircraft and were never seen again.

    Charles also said "America First." He was right about that too.

    http://www.charleslindbergh.com/americanfirst/speech.asp

    The first non-stop flight across the Atlantic happened in a plane equipped with two Rolls-Royce Eagle 360 hp engines.

    “Charles also said “America First.” He was right about that too.” Not in the context of the first non-stop flight across the Atlantic, he wasn’t.

    Read More
    • Replies: @Buzz Mohawk
    Oh dearieme! I am fully aware of, and in admiration of, Alcock and Brown.

    In 1919 those two heroes flew a Vickers Vimy from St. John's Newfoundland to a bog in Ireland, covering a distance of 1,890 miles, winning the Daily Mail Prize for the first non-stop flight across the Atlantic. It was a tremendous thing, and I love everything about it.

    Lindbergh won the Orteig Prize in 1927 for the first non-stop flight from New York City to Paris, a distance of 3,500 miles. He flew solo for 33 1/2 hours to accomplish this. Others died trying. This flight was at the absolute limit of possibility at that time, and it was justifiably celebrated around the world.

    Alcock and Brown deserved equal recognition at the time of their achievement, I think, but obviously the mass media fame machine hadn't yet grown into the monster it would become. Lindbergh became the first modern celebrity in 1927 because already things had changed -- perhaps also because his flight was a magnitude beyond any previous one, including that of A&B, and maybe because he did it alone in a little, personal aircraft people could identify with.

    Lindbergh showed humanity that the world's major cities could be linked by air in a matter of hours. He foreshadowed, and went on to promote, air travel more than any other single human being.

    Regarding multiple engines, it is noteworthy that Alcock and Brown's biplane experienced trouble in one of its two Rolls-Royce Eagles, requiring one of the men to climb out on the wing to make repairs. They damn near died.

    Neither Lindbergh nor anyone of any knowledge, including myself, HAS EVER claimed that Lindbergh made the first flight across the Atlantic. That is a common misconception, just as your accusation of me is a common attempt to diminish the heroism and genius of Charles Lindbergh.

    And again, he was absolutely right about America First.

    , @Glaivester
    It was the first non-stop SOLO flight across the Atlantic. I believe it was the fourth non-stop flight in all, and the sixty-seventh person to go across (the previous three flights held a total of 66 people).
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  29. dearieme says:
    @Dieter Kief

    Something similar happened with the financial crash of the previous decade
     
    .


    I think I've never seen before, that somebody uses the example of the last financial desaster to explain something else.

    A little bit baffeld (no - enjoyed, really - maybe quite like Piltdownman in No. 10 above).

    (( And I'm of ourse reminded of Gerd Gigerenzer's work: Understanding risk)).

    “Gerd Gigerenzer’s work: Understanding risk”: excellent book. Damn near everyone ought to read it.

    Read More
    • Replies: @Almost Missouri
    Thanks for the tip on Gigerenzer. I hadn't known about him before and his work looks like that rarity in modern academe: something genuinely useful.

    BTW, what's the over/under on when the SJWs decide that old white male Gigerenzer's "natural frequencies" and "recognition heuristics" are really just code for "racism is rational"? Or will the technical language and intellectual demands of Gigerenzer's work keep the notoriously stupid SJWs at bay indefinitely?
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  30. Steve You are getting close to my wheelhouse to the extent I might have one. The decision guidance that reservoir operators use for operational and release decisions is known as a “rule curve.” It provides guidance for variables like reservoir storage level, time of year, etc. So on Feb 1, the rule curve helps determine appropriate reservoir level/storage capacity and outflow for that date, all of which should be within given ranges. Rule curves get updated in order to reflect changes in land cover, runoff, and yes climate. I never have run a dam or calculated a rule curve, but I believe it allows for some judgement and wiggle room. I can’t describe the flood control-storage balance any better than Steve did (releases in Feb vs storage in August).

    You have a lot of readers with good comments. This is not the first time this has happened out West and there is in fact a history of it. A good example was @ Glen Canyon Dam in 1983. Given all the interest, readers may be interested in this article:

    http://www.colorado.edu/geography/geomorph/envs_5810/rhodes_84.pdf

    Something similar happened w the Army Corps of Engineers and its big Missouri River storage system in 2011

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    • Replies: @anon
    Interesting. Especially the fact that optimizing storage increases risk of flood control -- the other rationale of the system.

    Who/Whom.
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  31. @Anonymous Nephew
    "As i noted on the previous thread, the big question is what is the character of the rock under the regular spillway."

    Following this story from the UK, I've waited for someone to ask that vital question at a press conference, and I've not heard it asked. Are journalists all English graduates these days?

    I had a look at wiki btw, and Oroville is the 16th largest dam in the world, by volume of water held back. 4 billion cubic metres of water which IIRC is 4 billion (long) tonnes. But it's dwarfed by the Aswan Dam, which holds back 169 billion cubic metres of water and is presumably the reason why Egypt won't be going to war with Israel ever again. One large missile to that dam and it's goodbye Egypt, save for a few thousand desert Bedouin.

    “Are journalists all English graduates these days?”

    Worse: Journalism graduates. English graduates might have accidentally read some literature. The whole point of Journalism School is to produce mindless adherence to The Narrative. Independent thought and even just curiosity are ruthlessly exterminated.

    Read More
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  32. @eah
    if the main spillway holds up to the pounding its (sic) taking

    What "pounding"? -- looks like normal use to me -- a Challenger-like special inquiry is in order to look into the design, construction, and inspection/maintenance of the main spillway -- its dramatic failure is a scandal.

    Also the 'emergency spillway' -- aka a hillside -- is a joke.

    I have been saying the same. An *independent* review of the decision making process for making infrastructure investments and improvements at California’s dams is in order. Hopefully not another 9-11 commission, which was a joke and a farce.

    Yes, calling that emergency outlet a “spillway” is hilarious. You called it exactly what it is, a hillside.

    For a dam of this size?

    How many people are going to get canned? How much will the decision process change?

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  33. Anonym says:
    @Anonymous Nephew
    "As i noted on the previous thread, the big question is what is the character of the rock under the regular spillway."

    Following this story from the UK, I've waited for someone to ask that vital question at a press conference, and I've not heard it asked. Are journalists all English graduates these days?

    I had a look at wiki btw, and Oroville is the 16th largest dam in the world, by volume of water held back. 4 billion cubic metres of water which IIRC is 4 billion (long) tonnes. But it's dwarfed by the Aswan Dam, which holds back 169 billion cubic metres of water and is presumably the reason why Egypt won't be going to war with Israel ever again. One large missile to that dam and it's goodbye Egypt, save for a few thousand desert Bedouin.

    Following this story from the UK, I’ve waited for someone to ask that vital question at a press conference, and I’ve not heard it asked. Are journalists all English graduates these days?

    This is a definite problem. Journalism is a destination sought by people who enjoy writing but can’t get something that will pay better. If they had some logical or argumentative skill, they might do law. If they had mathematical skill, then engineering, business, management or medicine would be a more lucrative and secure option.

    It is a bit like the occupation of “driver” as mentioned by Steve before. People become drivers not because they have driving aptitude, but because they suck at everything else so bad that their comparative advantage is in driving. So it is with a lot of journalists. They can at least write somewhat entertainingly.

    Since the 1990s the internet has been slowly and steadily drinking the milkshake of the press and visual media. Jobs have been shrinking. You might get a few people who are so very good at writing that they go into the field, but most smart people would avoid it. Look at the people who have made it as bloggers. Our host, a national merit scholar. Glenn Reynolds, a law professor. Pro blogging makes New York look like a small flyover town, in terms of “making it”. So my guess is that they would make it as journalists or opinion writers (at least, if Steve stopped noticing he would be employable). Everyone else, not so much.

    Read More
    • Replies: @Steve Sailer
    A very large proportion of professional journalists were English majors in college.

    The ability to write quality prose fast is a talent that most people don't have. The ability to edit other people's prose might be even rarer.

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  34. @Anonymous Nephew
    "As i noted on the previous thread, the big question is what is the character of the rock under the regular spillway."

    Following this story from the UK, I've waited for someone to ask that vital question at a press conference, and I've not heard it asked. Are journalists all English graduates these days?

    I had a look at wiki btw, and Oroville is the 16th largest dam in the world, by volume of water held back. 4 billion cubic metres of water which IIRC is 4 billion (long) tonnes. But it's dwarfed by the Aswan Dam, which holds back 169 billion cubic metres of water and is presumably the reason why Egypt won't be going to war with Israel ever again. One large missile to that dam and it's goodbye Egypt, save for a few thousand desert Bedouin.

    “One large missile to that dam and it’s goodbye Egypt”

    Well, perhaps–if the missile is nuclear tipped. The Aswan Dam is a pretty thick embankment. You’d need a lot of conventional explosives to get through that.

    Of course, the Israelis do have that (nukes, that is (as well as lots of conventionals.))

    It’s been said that Israel is a “one nuke country” because it is so small, but it is less noted that Egypt may be a one nuke country as well, but for different reasons.

    Read More
    • Replies: @Buffalo Joe
    Almost, In WWII the Brits had a dam busting bomb the was shaped like a 50 gallon drum. The bomb was to be dropped sidewise and skip across the dam lake and impact against the backside of the dam, intending to cause failure. I remember watching a doc about it, but I can't remember if it was successfully deployed.
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  35. Anonym says:

    For those who haven’t, googling “dam failure”, including the image search, is interesting. Video is even better.

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  36. Alice says:

    I made my homeschooled kids (8 and 10) calculate how much water their old town would be under if the dam failed. They won’t grow up to be journalists…

    Did the same for the Sacramento river valley. This story isn’t getting better.

    Also figured out how much water is being poured through the spillway, in terms of usage. In a few hours, it’s the *yearly* water usage of Minneapolis.

    Is anyone talking about the downstream effect? The Sac valley/central valley levee system below this? At 100,000 CFS indefinitely, does this mean Oroville will be flooded to save the dam? Can the sac river levees hold this? For how many days/weeks?

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  37. Hodag says:

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

    The above link goes to a Monday podcast featuring an interview with a dam safety expert about Oroville.

    It is an hour long and well worth the listen.

    One of the many things I learned is the emergency spillway was never maintained and is a menace. Trees were allowed to grow there which made it’s erosion inevitable. Also, the bedrock was once exposed to atmosphere so is weathered or the technical term is rotton. I have no idea if that affects anything.

    Another takeaway is the soil in the dam is saturated. When they turned off the spillway there were jets of water flowing into the spillway from the saturated ground, as evidenced by this picture here

    If the soils are saturated by a week of rain the slabs of the spillway will continue to lift, they will fail back to the spillway and maybe the spillway stops working. The the lake continues to rise up to the emergency spillway….Which does not work.

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  38. @dearieme
    "Gerd Gigerenzer’s work: Understanding risk": excellent book. Damn near everyone ought to read it.

    Thanks for the tip on Gigerenzer. I hadn’t known about him before and his work looks like that rarity in modern academe: something genuinely useful.

    BTW, what’s the over/under on when the SJWs decide that old white male Gigerenzer’s “natural frequencies” and “recognition heuristics” are really just code for “racism is rational”? Or will the technical language and intellectual demands of Gigerenzer’s work keep the notoriously stupid SJWs at bay indefinitely?

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    • Replies: @Dieter Kief
    Understandig Risk ctd.

    Could you by any means keep quiet about Gerd Gigerenzer being racist?
    I'm - ehe - almost - - kidding. Quite some intellectuals in Germany follow his work - he is featured in influential papers - and nobody came up with this racism thing as far as I've seen. So I knock on wood three times... - (your thought, that Gigerenzer might argue in a way, that is a little bit too complex for the alarmist's armada of dysfunctional thinking to realize that there might be a chance for them to act - - - is an approved method indeed.

    Hegel and Kant for example, were very conscious of the danger of saying things, that might bring them in jail or cost them their jobs - therefor they used to argue in a way that set censors to sleep - or else: Outsmarted the narrow minded via double-talk, abstraction, indirekt reasonning and so forth.

    And Goethe used to say that he loved writing about controversial subjects in a way that left the not so bright but angry rather puzzeld about the question what's a stake at all. Faust is so funny because of this puzzle-structure, that's woven right into it. Faust doesn't work without it's fast wit.

    Kant even went as far as to claim that you don't necessarily have to tell the whole truth.
    The only restriction he made: All you do say, after thorough consideration, h a s to be true.

    Ahh - and the most influential of German Gigerenzer-proponents - was a journalist (he lived 15, 16, 17 working-hour days week in week out - and died with 51 a few years ago....which in itself is tragic and comic, if you think about it - because - of course - - no severer risk for your heart (he indeed died of a heart-attac) - than being overweight and working in a stressful environment for well over 15 daily hrs. at least...he read and praised Gigerenzer, but didn't understand how big (and simple structured) his own personal risk was - - - ). Therefor: The existential safety-package should always include some kind of personal self-reflection - be it Freudian or otherwise...

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  39. Clyde says:

    Solid interview with a man in the dam building business for 40 years

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

    Scott Cahill: Exactly. What they had said is only probably a day ago was that this wasn’t a significant problem because if we simply close the gates, the valves on the top end of the principle spillway, then the water will rise and spill over the emergency spillway and the emergency spillway has a magnificent capacity to move water. Well, when they allowed just a bit of water to run over the emergency spillway they soon found with the velocities of only a portion of the water that could be moving over that emergency spillway. They had such severe scour that they anticipated a failure of the structural elements within 45 minutes.

    That initiated them moving people out of the inundation zone beneath the dam. And now I believe the thought is that the cut back on the principle spillway is slower than the failure mode on the emergency spillway, so they’re going to vent water down that principle spillway as much as they can without failing that element.

    excerpt

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    • Replies: @The Last Real Calvinist
    Thanks for that link; it's a really good interview with lots of specialist information.

    An ominous quotation from Cahill here:

    There are many dams which are in horrible, horrible shape, unbelievable shape across the United States. Many states have 4,000 dams. Many states have 2,000 and 3,000 dams. Of those dams I would imagine that 20% are in an absolutely untenable situation.

    When we look at this dam, which is a highly regulated dam, a dam more highly regulated than almost any others. They had an emergency spillway filled with trees. They had a principle spillway that was in the process of failing and had been for years. So, if this can exist on one of the most highly regulated dams then one can just interpolate and imagine what the rest of the situation is like.

    Dams and infrastructure in general in these United States have been ignored since they were constructed; many of them 100 years old. The mass of them more than 50 years old. And the design life when they were constructed, generally 50 years. We – it’s hard politically to go back and spend the money proactively to develop safety because nothing has happened. And so, with dam safety, time and time again we act after the horrible event. Something really horrible happens and someone reacts to that and says, “You know I will never let this happen again”. And indeed we move forward. And then the pressure is off and it’s not frightening anymore and we go back to a level of complacency that allows us to get where we stand today.

    Dams are in terrible shape in the United States as are all of our infrastructure, bridges, 600,000 bridges with 27% of them not meeting their minimum requirements. A number of these high hazard dams are not even close. There’s a report card given out by the American Society of Civil Engineers and many states, dam inventories are getting D’s, D minuses, D plusses. It’s hard to believe. Certainly someone in the 1960’s would never believe that the United States would have these issues, but we’ve ignored them far too long . . . .
     
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  40. @eah
    if the main spillway holds up to the pounding its (sic) taking

    What "pounding"? -- looks like normal use to me -- a Challenger-like special inquiry is in order to look into the design, construction, and inspection/maintenance of the main spillway -- its dramatic failure is a scandal.

    Also the 'emergency spillway' -- aka a hillside -- is a joke.

    The main spillway supposedly would have been fine … if there were two of them. And yes, would also be nice to have a third “emergency spillway” that’s an actual … spillway.

    Two is one, and one is none–what a great saying. Reminds me of “Penny-wise and pound-foolish.”

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  41. @Rod1963
    A concrete emergency spillway was recommended over 12 years ago by some enviro groups who saw the flaws in the dirt spillway but was nixed because of cost and no one thinking it would ever be used.

    I love political thinking, it's so otherworldly and bizarre. Imagine a car designed by the buggers. It would probably be a watermelon with four toy wheels and a $20,000 price tag.

    What do you think you are driving Now? Your car was designed by a government committee.

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  42. ic1000 says:

    Former geologist here. What I’ve gleaned from Steve’s commentariat (but emphatically not from following the mainstream news) is that the multiple failures at Oroville are not uncorrelated, because they trace back to a fundamental issue: the bedrock at the dam site is highly fractured.

    When we think of bedrock, we typically think of the granite of El Capitan, or impressive roadcuts like Sideling Hill. However, some rock is inherently weak (unconsolidated), or is prone to fracture and weathering, or has been subject to immense tectonic forces (e.g. pictures of conjugate fractures in rock at the San Andreas Fault here).

    These are not observations that are new to the 21st Century, or to the 20th Century. For example, read the first paragraph of UCSB faculty Douglas Burbank & Brian Clarke’s ~2011 essay The Role of Rock Fracture in Erosion.

    The engineers who designed Oroville Dam in the 1980s were obviously not blind to the implications of building on weak bedrock, or of the facts on the (chosen) ground. There are sure to be damning memos in the archives. But for whatever reasons, the dam was built the way that it was.

    1. Failure at the middle of the main spillway — The concrete of the spillway cracked because it was undermined — the rock beneath it must have been eroded away by water flow over the decades that the structure has been in use. This happened because that rock was unconsolidated.

    2. Risk that sustained water release at 100,000 to 150,000 cfm will cause the top part of the spillway to break up, undermining the spillway gate itself — Again, unconsolidated rock.

    3. Loss of the ability to release 14,000 cfm through the power station — Result of #1.

    4. Inability of the auxiliary spillway to operate at 12,500 cfm, 5% of its design capacity of 250,000 cfm — Photos taken Monday show that the emergency spillway flow eroded a deep channel in the hillside in a matter of days, and it was quickly expanding uphill, towards the spillway dam. In addition, the water cresting that 30 foot concrete spillway was likely to excavate spaces underneath it, risking its failure. Both are consequences of the unconsolidated nature of the bedrock at the site.

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  43. dearieme says:

    Here’s an interview about the dam that people might enjoy. You don’t have to listen – there’s a transcript.

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

    Hat-tip to

    http://www.oftwominds.com/blog.html

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    • Replies: @res
    Thanks for mentioning the transcript. That was illuminating.
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  44. I have made this point before and I will again but some here will still argue with me. America’s innumeracy and that of the press and even Steve’s faltering explanation from a few days ago (through which he has finally fought to clarity) is exacerbated by our clumsy use of Olde English units of measure.

    Switching from acres to miles to cubic feet to inches per hour to gallons per minute to pounds pressure is very awkward because one is basically switching between number base systems. All this disappears in the metric system where volume and weight (and therefore pressure) are mutually related by–wait for it–the density of WATER!

    WELL WHAT DO YOU KNOW???? ONE WOULD ALMOST SUSPECT THAT THE GUYS WHO CAME UP WITH THAT SYSTEM HAD SOME INSIGHT INTO THE FUNDAMENTAL NATURE OF THINGS HERE FOR HUMANS ON EARTH!!!!

    And to top it off, they got rid of clumsy acres per square mile etc. and made everything multiples of ten, the same base as our number system.

    So, to reiterate, in the metric system clear thinking becomes much easier. And no, as potential commenters will no doubt argue, this is not an issue for ME PERSONALLY because I scored in the 99th percentile in math and general reasoning–which is the very reason I can see the confusion in the minds of those around me and is what enables me to recognize that it is a substantial issue for many of my struggling contemporaries.

    Steve’s calculations are interesting but are not the whole story. He mentions that “As far as I can tell, the 14k cfs through the power station under the dam has been shut down for several days now, although I’ve read different explanations for why that is”.

    As Unit472 in comment 23 says, pressure varies with depth and it may well be that the machinery or gates that regulate the flow of water to the turbines cannot handle the pressure created by the depth of water currently in the reservoir. A partially opened gate is subject to different cantilever-like torsional forces than one completely closed, so since pressure varies directly with depth, the gates or water wheels or whatever may not be able to handle the added pressure. Just speculating.

    But this brings up another issue. Steve related all this to the housing crisis and the thinking surrounding it. Very good. Now to the meat and potatoes.

    As Unit472 alluded to above, rate of flow is contingent upon pressure and pressure varies with depth. So, as water falls from sky, depth of water level rises and flow from orifice–not at overflow on surface, but orifice below surface–increases. If rate of increase in depth is faster than outflow then rate of outflow will not be constant but will increase with pressure. At some point, increased pressure will create increase velocity of outflow to the extent that inflow and outflow become equal–assuming system components can handle the pressure and flow. Krugman calls this economic instance of a related-rate problem “comparative advantage”. A less efficient manufacturer can still make and export a product to a more efficient manufacturing nation if the two engage in frictionless trade because at some volume point any differential in cost per unit achieves equilibrium. This is fundamental reasoning behind globalism.

    But as Steve points out, there are pitfalls in reasoning from mathematical models and applying them to people and nationstates. Errors accumulate or rather cascade; the failure of one component–a rubber O ring for example–leads to failure of others until cataclysm. For just this reason, engineers design in huge safety margins and always try to err on the side of too much. Only in competitive sports is constant threat of breakage from expected use accepted, examples are masts of racing yachts and engines of Formula One cars.

    As banking has become more like a sport for the rich and less like a community investment designed like dams, i.e. major investments built to protect and enhance human quality and sacredness of life, breakage and ruin have become acceptable. Casino Wall Street no longer treats people as most valuable commodity and wants to dissolve the boundaries of the nation state which act as a bulwark against the vagaries of economic cycles just as a dam enables humans to regulate the seasonal flooding in a river and turn it into an communally-shared asset.

    “The Truth is the Whole” is not just a clever phrase.

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    • Replies: @Austrian
    I raised the metric issue in the previous Oroville thread.

    Metric opponents claim that the human scale imperial system is more intuitive, or, at least, that it doesn't matter. All I can see is fairly smart people struggling with basic calculations and estimations, when put to the test.

    A metric changeover has benefits in fat tail events like this emergency, or in the long tail of millions of articles by journalists who just repeat numbers and measurements literally from experts or sources but are incapable at relating them and reasoning about them on their own.
    , @Dieter Kief

    Only in competitive sports is constant threat of breakage from expected use accepted, examples are masts of racing yachts and engines of Formula One cars.
     
    Ferdinand Porsche once put it this way: If you construct a racing car, keep in mind that it doesn't have to go futher than right over the finish line.
    Hmm
    You are taking Steve Sailer's analogy between the dam-problems and the financial crisis a bit further:

    As banking has become more like a sport for the rich and less like a community investment designed like dams, i.e. major investments built to protect and enhance human quality and sacredness of life, breakage and ruin have become acceptable.
     
    -

    I'd like to add: The larger picture might well be, that banking as sports (of sorts) for the rich is directly related to your other thought: That this kind of new sporty banking is a hint at the other aspect that you mention: The sacredness of (communal) life - - -

    If this was right, it would show, that sports is simply not good enough as a value-source for society as a whole.

    Sports as the new cult (in the place of religion) - might just not be complex enough to really fullfill the functions that religion once fullfilled.

    This might be part of an explanation, why those bankers and hedgers etc. always got away - and still get away - with their insane profits: Because the public, more and more obsessed with winners and losers (= sports) - is somewhat disarmed - morally or ethically disarmed, so to speak, as soon as sports step in as the new big paradigm of how things should be handled just and well.

    - Religion was (is) much more complex than sports: There's so much more than winners and losers - and all that is simply lost, if secularisation is taken too easily - - - without Max Weber - without Kant and Mill and Wittgenstein (etc.).

    By the way: Kant and Wittgenstein - and Fromm and Habermas - none o them said, that they'd be replacing religion - or that you should replace the Judeo-Christian tradition, even. - BE CAREFUL WITH THAT AXE, EUGINE - to paraphrase Pink Floyd...

    , @newrouter
    "in the metric system clear thinking becomes much easier."

    Yes Merkel's Germany has much "clear thinking".
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  45. @PiltdownMan
    This is a really nice article, Steve.

    I often rant about the lack of numeracy among highly educated people. Your analysis is a v̶e̶r̶y̶ ̶g̶o̶o̶d̶ perfect example of the great insight grade-school math combined with intelligence can yield, when one is trying to understand a current event or the news.

    I'm going to bookmark this and periodically email it to people. Who knows? They may read your other stuff and like it, too.

    Gateway to iSteve! :)

    “Water can flow, or it can crash; be water, my friend.” (Bruce Lee)

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  46. dearieme says:

    How NOAA can turn a useful summary of events into a lie about Global Warming.

    https://notalotofpeopleknowthat.wordpress.com/2017/02/15/noaa-the-oroville-dam/

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  47. Emergency Spillway implies that you would only use it in an emergency and trust that your engineering covered all contingencies. Doesn’t look like they did. Reminds me of a story I heard from WWII. The parachute packers used to hand the pilots their emergency chutes and tell them…”If I doesn’t work, bring it back and we’ll give you another.”

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  48. Anonymous says: • Disclaimer

    A key element to this drama is a lie: the second spillway is not actually a spillway it’s a hillside.

    So re the multiple backup systems failure to remain independent: if everyone keeps talking about two spillways when there is actually only one then there are bound to be unexpected outcomes…

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  49. A poster at Free Republic claims there is now hydraulic erosion right outside the main spillway, toward the side of the emergency spillway, and fairly high up, above the huge hole. See post #999:

    http://tinyurl.com/j6rd5ls

    They include a photo of what they allege to be concrete-pumping work on these spots as it was undertaken last night, but it’s too dark, for me at least, to tell what’s going on. The photo appears to have been taken from the opposite side of the dam, maybe from the far end of the parking lot?

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  50. anonymous says: • Disclaimer

    About probability of failure, a while back it was assumed that disk drive failures were independent, so MTBF (Mean Time Between Failure) of disk storage arrays that have many drives was calculated based on the assumption that drive failures were uncorrelated.

    Then history revealed that the drives put in large storage arrays were often from the same batch of disks and had been manufactured together, so they all failed at pretty much the same time. Failure was correlated.

    Another problem is that the drives have so much software today that a correlated software bug often shows up in a batch at about the same time, due to similar usage or some such.

    Another interesting example of this is the US and USSR moon rockets. The Saturn V first stage had 5 main engines. It had 0 failures.

    The Soviet N-1 first stage had 30 engines. It had 0 successes. If 30 things have to all work perfectly for the system to work, it’s more likely to fail than if 5 things have to work perfectly.

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  51. @Rod1963
    A concrete emergency spillway was recommended over 12 years ago by some enviro groups who saw the flaws in the dirt spillway but was nixed because of cost and no one thinking it would ever be used.

    I love political thinking, it's so otherworldly and bizarre. Imagine a car designed by the buggers. It would probably be a watermelon with four toy wheels and a $20,000 price tag.

    Did somebody say car designed by politicians?

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  52. JerryC says:

    The main spillway seems to be holding up OK so far in that the damage does not appear to be moving towards the top of the spillway. Fingers crossed.

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  53. @dearieme
    The first non-stop flight across the Atlantic happened in a plane equipped with two Rolls-Royce Eagle 360 hp engines.

    "Charles also said “America First.” He was right about that too." Not in the context of the first non-stop flight across the Atlantic, he wasn't.

    Oh dearieme! I am fully aware of, and in admiration of, Alcock and Brown.

    In 1919 those two heroes flew a Vickers Vimy from St. John’s Newfoundland to a bog in Ireland, covering a distance of 1,890 miles, winning the Daily Mail Prize for the first non-stop flight across the Atlantic. It was a tremendous thing, and I love everything about it.

    Lindbergh won the Orteig Prize in 1927 for the first non-stop flight from New York City to Paris, a distance of 3,500 miles. He flew solo for 33 1/2 hours to accomplish this. Others died trying. This flight was at the absolute limit of possibility at that time, and it was justifiably celebrated around the world.

    Alcock and Brown deserved equal recognition at the time of their achievement, I think, but obviously the mass media fame machine hadn’t yet grown into the monster it would become. Lindbergh became the first modern celebrity in 1927 because already things had changed — perhaps also because his flight was a magnitude beyond any previous one, including that of A&B, and maybe because he did it alone in a little, personal aircraft people could identify with.

    Lindbergh showed humanity that the world’s major cities could be linked by air in a matter of hours. He foreshadowed, and went on to promote, air travel more than any other single human being.

    Regarding multiple engines, it is noteworthy that Alcock and Brown’s biplane experienced trouble in one of its two Rolls-Royce Eagles, requiring one of the men to climb out on the wing to make repairs. They damn near died.

    Neither Lindbergh nor anyone of any knowledge, including myself, HAS EVER claimed that Lindbergh made the first flight across the Atlantic. That is a common misconception, just as your accusation of me is a common attempt to diminish the heroism and genius of Charles Lindbergh.

    And again, he was absolutely right about America First.

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    • Agree: Whoever
    • Replies: @dearieme
    What an extraordinarily long-winded way to avoid the point that the argument against twin engines was utter twaddle.
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  54. Bruce says:
    @AnotherDad

    If the spillway failed over several hours it might be worth cutting a notch at the top of the dam. This would be risky, since the water might eat through crappy concrete and blow the whole dam. So save it for a last resort.
     
    Uh ... no!

    It's an earthfill dam. The one thing you don't want to do if have water running over the dam. That's the whole point of the "emergency spillway" is to have a outlet for overflow that does *not* send water over the top of the dam. (That's the whole point of spillways in general.)

    ~~~

    There are two points here:

    1) The emergency spillway is a genuine design failure--a genuine screwup of us dead white males. (Usually our stuff is pretty awesome and it's the disaster of modernity--letting women and leftists be in charge--that's the problem.)

    I've seen a lot of different spillways of various sorts. But the common element is that you get the water spilling *away* from critical structures. Often even on earthen dams there's a concrete lining on the critical section where water would be moving--potentially quickly--next to the dam structure. This always extends until the water is *away* from the dam and moving mostly *horizontally*. This dam has a concrete lip of 30' or so, creating a lot of force, but then doesn't have the landing area for that water reinforced. Worse the spilled water seems to have a "recollection" path--back near the primary spillway!--which is then subject to serious erosion. If they'd simply poured concrete running a couple hundred feet or so on down from the lip getting the water spread out and running parallel to the ground surface, any erosion would have been minimized and would have been far away from the structure that could be undermined.

    2) As i noted on the previous thread, the big question is what is the character of the rock under the regular spillway. If there's genuine 100 million year old Sierra Nevada granite ... the broken spillway is just dumping a lot of water into a rock canyon. No biggie. You can have it be a permanent feature. But if that hump of hill is just a pile of random aggregate, then blasting your 100,000 cfs down it, could serially eat out underneath the spillway eroding it back and back until you're eating away at the edge of the dam. Then you are in deep shit. It looks like there's a pretty massive piece of good rock in the flow near the break. But what is the rest of it like? With the water, i can't see what's there, what erosion is happening.

    ‘It’s an earthfill dam. The whole point of the spillway is to have water that does not go over the top of the dam.’

    Thanks.

    ‘The big question is the character of the rock under the regular spillway.’

    If I was dropping boulders from a helicopter into the hole, I’d use wire rope to hold them together. Let the energy of the water go into bouncing the boulders up and down and tangling themselves together, not into bouncing the boulders out of the hole. And I’d bolt wire ropes or I-beams to any visible rock under the spillway.

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    • Replies: @Anonymous Nephew
    "If I was dropping boulders from a helicopter into the hole, I’d use wire rope to hold them together. Let the energy of the water go into bouncing the boulders up and down and tangling themselves together, not into bouncing the boulders out of the hole."

    That is a very good idea. Same sort of thing that makes the Hesco Bastion better protection than a pile of rocks and sand. Seeing that the holes are random-size and shape, how about a steel-cable mesh bag filled with rocks, that could be dropped in a hole and would then conform to the hole shape and not leave too many big voids? A flexible gabion. But you'd need a lot of steel for such a bag, so maybe drilling holes and threading the rocks on would be better? Hmm. Bag's more elegant if you can make one. Make the bag from Kevlar or similar tough fibre, then link the bags together in situ? Wouldn't rust like steel.

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

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  55. Bruce says:
    @Steve Sailer
    The dam is, knock on wood, fine.

    If there isn't too much rain, they might get out of this with just a bill for a few hundred million bucks for fixing the main spillway and building a real emergency spillway or maybe a second primary spillway.

    ‘The dam is, knock on wood, fine.

    ‘they might get out of this with just a bill for a few hundred million bucks for fixing the main spillway and building a real emergency spillway or maybe a second primary spillway.’

    Thanks.

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  56. RH says:

    Hi Steve,

    In trying to estimate how much the coming precip might raise the level of the reservoir, don’t forget to include the rain that falls directly on the surface of the reservoir, rather than flowing in. It’s a lot of water. Also, a portion of the rain that falls on the ground of the watershed will be absorbed into the ground, i.e., not all of it will find its way into the impoundment.. In otherwords, an inch of rain in the watershed will not necessarily raise the reservoir by an inch.

    Cheers, Rob

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    • Replies: @Steve Sailer
    One inch of rain on the reservoir will raise the lake level by one inch. One inch of rain elsewhere might be absorbed (that's what has been keep Lake Cachuma north of Santa Barbara so low: the ground is so dry that rain just gets absorbed and never makes it to the lake) or it might melt some unknown amount of snow causing the lake to rise by more than one inch.

    So I just built a very simple model.

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  57. dearieme says:
    @Buzz Mohawk
    Oh dearieme! I am fully aware of, and in admiration of, Alcock and Brown.

    In 1919 those two heroes flew a Vickers Vimy from St. John's Newfoundland to a bog in Ireland, covering a distance of 1,890 miles, winning the Daily Mail Prize for the first non-stop flight across the Atlantic. It was a tremendous thing, and I love everything about it.

    Lindbergh won the Orteig Prize in 1927 for the first non-stop flight from New York City to Paris, a distance of 3,500 miles. He flew solo for 33 1/2 hours to accomplish this. Others died trying. This flight was at the absolute limit of possibility at that time, and it was justifiably celebrated around the world.

    Alcock and Brown deserved equal recognition at the time of their achievement, I think, but obviously the mass media fame machine hadn't yet grown into the monster it would become. Lindbergh became the first modern celebrity in 1927 because already things had changed -- perhaps also because his flight was a magnitude beyond any previous one, including that of A&B, and maybe because he did it alone in a little, personal aircraft people could identify with.

    Lindbergh showed humanity that the world's major cities could be linked by air in a matter of hours. He foreshadowed, and went on to promote, air travel more than any other single human being.

    Regarding multiple engines, it is noteworthy that Alcock and Brown's biplane experienced trouble in one of its two Rolls-Royce Eagles, requiring one of the men to climb out on the wing to make repairs. They damn near died.

    Neither Lindbergh nor anyone of any knowledge, including myself, HAS EVER claimed that Lindbergh made the first flight across the Atlantic. That is a common misconception, just as your accusation of me is a common attempt to diminish the heroism and genius of Charles Lindbergh.

    And again, he was absolutely right about America First.

    What an extraordinarily long-winded way to avoid the point that the argument against twin engines was utter twaddle.

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    • Replies: @Buzz Mohawk

    ...the argument against twin engines was utter twaddle.
     
    No, it wasn't, and that was not the essence of your comment, either.

    Nice try on your part at avoiding the point that you were wrong about claims for Lindbergh and what was actually significant about his New York-to-Paris (not just transatlantic) flight.

    "Utter twaddle," how cute.

    The point of all this is to relate things to Steve's point about the logical fallacy people fall into with regard to what they think is redundant engineering when it is in some cases just multiplying chances for failure.

    Good engineers know this.

    Good pilots understand all these issues around engines and the plusses and minuses of multi vs. single. There are times for both.

    Ever fly a Pilatus PC-12? I doubt it.

    "Cheers," as you say.

    , @Glaivester
    It doesn't make the argument twaddle. The fact that people succeeded with twin engines does not mean that it was less risky.

    Ultimately, I would think that all else being equal, it would be better to be in a single-engine plane than in a twin-engine plane that required both engines to be working to fly. A twin-engine plane is better if the plane can get by with only one engine if need be.
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  58. @RH
    Hi Steve,

    In trying to estimate how much the coming precip might raise the level of the reservoir, don't forget to include the rain that falls directly on the surface of the reservoir, rather than flowing in. It's a lot of water. Also, a portion of the rain that falls on the ground of the watershed will be absorbed into the ground, i.e., not all of it will find its way into the impoundment.. In otherwords, an inch of rain in the watershed will not necessarily raise the reservoir by an inch.

    Cheers, Rob

    One inch of rain on the reservoir will raise the lake level by one inch. One inch of rain elsewhere might be absorbed (that’s what has been keep Lake Cachuma north of Santa Barbara so low: the ground is so dry that rain just gets absorbed and never makes it to the lake) or it might melt some unknown amount of snow causing the lake to rise by more than one inch.

    So I just built a very simple model.

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    • Replies: @RH
    Hi Steve,

    Fair enough. Have just been reading articles and watching videos of the destruction of the Teton Dam in 1972. About two hours before the loss of the dam, a large whirlpool appeared a short distance in front of the dam. The fact that this, in conjunction with all the other problems, was still not enough for the authorities to admit that the dam was toast (and issue the appropriate warnings to the citizenry downstream) is a vivid practical illustration of the meaning of the word "denial".

    Regards, Rob
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  59. @dearieme
    What an extraordinarily long-winded way to avoid the point that the argument against twin engines was utter twaddle.

    …the argument against twin engines was utter twaddle.

    No, it wasn’t, and that was not the essence of your comment, either.

    Nice try on your part at avoiding the point that you were wrong about claims for Lindbergh and what was actually significant about his New York-to-Paris (not just transatlantic) flight.

    “Utter twaddle,” how cute.

    The point of all this is to relate things to Steve’s point about the logical fallacy people fall into with regard to what they think is redundant engineering when it is in some cases just multiplying chances for failure.

    Good engineers know this.

    Good pilots understand all these issues around engines and the plusses and minuses of multi vs. single. There are times for both.

    Ever fly a Pilatus PC-12? I doubt it.

    “Cheers,” as you say.

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  60. Some good interactive charts here: https://github.com/axibase/atsd-use-cases/blob/master/OrovilleDam/README.md

    I think that is some software/database company using the public Oroville dam data, and very similar calculations our host made, to demo their stuff.

    They come to similar conclusions as our host.

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  61. @Anonym
    Following this story from the UK, I’ve waited for someone to ask that vital question at a press conference, and I’ve not heard it asked. Are journalists all English graduates these days?

    This is a definite problem. Journalism is a destination sought by people who enjoy writing but can't get something that will pay better. If they had some logical or argumentative skill, they might do law. If they had mathematical skill, then engineering, business, management or medicine would be a more lucrative and secure option.

    It is a bit like the occupation of "driver" as mentioned by Steve before. People become drivers not because they have driving aptitude, but because they suck at everything else so bad that their comparative advantage is in driving. So it is with a lot of journalists. They can at least write somewhat entertainingly.

    Since the 1990s the internet has been slowly and steadily drinking the milkshake of the press and visual media. Jobs have been shrinking. You might get a few people who are so very good at writing that they go into the field, but most smart people would avoid it. Look at the people who have made it as bloggers. Our host, a national merit scholar. Glenn Reynolds, a law professor. Pro blogging makes New York look like a small flyover town, in terms of "making it". So my guess is that they would make it as journalists or opinion writers (at least, if Steve stopped noticing he would be employable). Everyone else, not so much.

    A very large proportion of professional journalists were English majors in college.

    The ability to write quality prose fast is a talent that most people don’t have. The ability to edit other people’s prose might be even rarer.

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    • Replies: @Anonym
    The ability to write quality prose fast is a talent that most people don’t have. The ability to edit other people’s prose might be even rarer.

    Now that I think about it, you are right re: ability to write quality prose, fast. It is uncommon. In terms of the top 2% or so in my graduating grade, none of us went into English as a major. It was all STEM. And as IQ would predict, we were all at or near the top of our class in English. We just chose more lucrative fields because we were also at the tops of our classes in math, physics, chem etc. But definitely the relatively innumerate journalist English major type exists, and is more common among women, and I would suspect due to the female brain thing, gay men.

    You obviously have more exposure to that world than I do. How many journalists would have the mathematical skills to be even a math teacher, let alone an engineer?
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  62. res says:
    @dearieme
    Here's an interview about the dam that people might enjoy. You don't have to listen - there's a transcript.

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

    Hat-tip to
    http://www.oftwominds.com/blog.html

    Thanks for mentioning the transcript. That was illuminating.

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  63. @Almost Missouri
    Thanks for the tip on Gigerenzer. I hadn't known about him before and his work looks like that rarity in modern academe: something genuinely useful.

    BTW, what's the over/under on when the SJWs decide that old white male Gigerenzer's "natural frequencies" and "recognition heuristics" are really just code for "racism is rational"? Or will the technical language and intellectual demands of Gigerenzer's work keep the notoriously stupid SJWs at bay indefinitely?

    Understandig Risk ctd.

    Could you by any means keep quiet about Gerd Gigerenzer being racist?
    I’m – ehe – almost – – kidding. Quite some intellectuals in Germany follow his work – he is featured in influential papers – and nobody came up with this racism thing as far as I’ve seen. So I knock on wood three times… – (your thought, that Gigerenzer might argue in a way, that is a little bit too complex for the alarmist’s armada of dysfunctional thinking to realize that there might be a chance for them to act – – – is an approved method indeed.

    Hegel and Kant for example, were very conscious of the danger of saying things, that might bring them in jail or cost them their jobs – therefor they used to argue in a way that set censors to sleep – or else: Outsmarted the narrow minded via double-talk, abstraction, indirekt reasonning and so forth.

    And Goethe used to say that he loved writing about controversial subjects in a way that left the not so bright but angry rather puzzeld about the question what’s a stake at all. Faust is so funny because of this puzzle-structure, that’s woven right into it. Faust doesn’t work without it’s fast wit.

    Kant even went as far as to claim that you don’t necessarily have to tell the whole truth.
    The only restriction he made: All you do say, after thorough consideration, h a s to be true.

    Ahh – and the most influential of German Gigerenzer-proponents – was a journalist (he lived 15, 16, 17 working-hour days week in week out – and died with 51 a few years ago….which in itself is tragic and comic, if you think about it – because – of course – – no severer risk for your heart (he indeed died of a heart-attac) – than being overweight and working in a stressful environment for well over 15 daily hrs. at least…he read and praised Gigerenzer, but didn’t understand how big (and simple structured) his own personal risk was – – – ). Therefor: The existential safety-package should always include some kind of personal self-reflection – be it Freudian or otherwise…

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  64. @bjdubbs
    Get some pipes and some pumps and that should do it. Of course it might be more complicated than that but it's not clear why. The water draining over the lip isn't going at a huge rate, I'm sure pumps & pipe can probably do it faster.

    The world’s highest capacity pump cost half a billion, took years to build and install, and moves water at one quarter the rate going down the main spillway at Oroville as I type. I assume the idea touted by others here of multiple siphons is more feasible, but I’m skeptical of that too.

    http://gizmodo.com/5800072/the-worlds-largest-water-pump-moves-15-olympic-sized-swimming-pools-every-minute

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  65. Austrian says:
    @ThreeCranes
    I have made this point before and I will again but some here will still argue with me. America's innumeracy and that of the press and even Steve's faltering explanation from a few days ago (through which he has finally fought to clarity) is exacerbated by our clumsy use of Olde English units of measure.

    Switching from acres to miles to cubic feet to inches per hour to gallons per minute to pounds pressure is very awkward because one is basically switching between number base systems. All this disappears in the metric system where volume and weight (and therefore pressure) are mutually related by--wait for it--the density of WATER!

    WELL WHAT DO YOU KNOW???? ONE WOULD ALMOST SUSPECT THAT THE GUYS WHO CAME UP WITH THAT SYSTEM HAD SOME INSIGHT INTO THE FUNDAMENTAL NATURE OF THINGS HERE FOR HUMANS ON EARTH!!!!

    And to top it off, they got rid of clumsy acres per square mile etc. and made everything multiples of ten, the same base as our number system.

    So, to reiterate, in the metric system clear thinking becomes much easier. And no, as potential commenters will no doubt argue, this is not an issue for ME PERSONALLY because I scored in the 99th percentile in math and general reasoning--which is the very reason I can see the confusion in the minds of those around me and is what enables me to recognize that it is a substantial issue for many of my struggling contemporaries.

    Steve's calculations are interesting but are not the whole story. He mentions that "As far as I can tell, the 14k cfs through the power station under the dam has been shut down for several days now, although I’ve read different explanations for why that is".

    As Unit472 in comment 23 says, pressure varies with depth and it may well be that the machinery or gates that regulate the flow of water to the turbines cannot handle the pressure created by the depth of water currently in the reservoir. A partially opened gate is subject to different cantilever-like torsional forces than one completely closed, so since pressure varies directly with depth, the gates or water wheels or whatever may not be able to handle the added pressure. Just speculating.

    But this brings up another issue. Steve related all this to the housing crisis and the thinking surrounding it. Very good. Now to the meat and potatoes.

    As Unit472 alluded to above, rate of flow is contingent upon pressure and pressure varies with depth. So, as water falls from sky, depth of water level rises and flow from orifice--not at overflow on surface, but orifice below surface--increases. If rate of increase in depth is faster than outflow then rate of outflow will not be constant but will increase with pressure. At some point, increased pressure will create increase velocity of outflow to the extent that inflow and outflow become equal--assuming system components can handle the pressure and flow. Krugman calls this economic instance of a related-rate problem "comparative advantage". A less efficient manufacturer can still make and export a product to a more efficient manufacturing nation if the two engage in frictionless trade because at some volume point any differential in cost per unit achieves equilibrium. This is fundamental reasoning behind globalism.

    But as Steve points out, there are pitfalls in reasoning from mathematical models and applying them to people and nationstates. Errors accumulate or rather cascade; the failure of one component--a rubber O ring for example--leads to failure of others until cataclysm. For just this reason, engineers design in huge safety margins and always try to err on the side of too much. Only in competitive sports is constant threat of breakage from expected use accepted, examples are masts of racing yachts and engines of Formula One cars.

    As banking has become more like a sport for the rich and less like a community investment designed like dams, i.e. major investments built to protect and enhance human quality and sacredness of life, breakage and ruin have become acceptable. Casino Wall Street no longer treats people as most valuable commodity and wants to dissolve the boundaries of the nation state which act as a bulwark against the vagaries of economic cycles just as a dam enables humans to regulate the seasonal flooding in a river and turn it into an communally-shared asset.

    "The Truth is the Whole" is not just a clever phrase.

    I raised the metric issue in the previous Oroville thread.

    Metric opponents claim that the human scale imperial system is more intuitive, or, at least, that it doesn’t matter. All I can see is fairly smart people struggling with basic calculations and estimations, when put to the test.

    A metric changeover has benefits in fat tail events like this emergency, or in the long tail of millions of articles by journalists who just repeat numbers and measurements literally from experts or sources but are incapable at relating them and reasoning about them on their own.

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  66. Sunbeam says:

    Not much to add to this.

    I would like to point out that this country has an awful lot of big public works that were completed in days gone by (up to a century for a number of them).

    They were built for a reason, and they accomplished their purpose. However nothing lasts forever, and eventually you have to put some major work into things like this.

    Granted this particular incident is an unusual amount of rainfall, but I read an article or two a few years ago about the poor condition of the water works in California particularly in the Northern section. This made me think of this.

    There there is the “Man vs. Nature” fight of the Army Corp of Engineers keeping the river flowing by New Orleans instead of where it seems to want to go. One day they lose that one.

    Seems a lot harder for us to build big stuff than it was back in the day. Regulations (some of them good actually; there are a lot of 19th century retaining ponds and waterworks that have come apart at the seams over the last few decades) are a part of it of course.

    But geez imagine them building the Golden Gate Bridge now. You just thought the Big Dig took forever.

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    • Replies: @johnmark7
    I've been in Sacramento since 1986. This is the third time we've had an "unusual" amount of rainfall. 3 in 30 years seems fairly frequent to me as this SFGate article also explains:

    http://www.sfgate.com/bayarea/article/California-due-for-biblical-flooding-arkstorm-10921370.php

    If your area had a major earthquake every ten years, you might build your home even more diligently as someone else said - penny wise, pound foolish.
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  67. RH says:
    @Steve Sailer
    One inch of rain on the reservoir will raise the lake level by one inch. One inch of rain elsewhere might be absorbed (that's what has been keep Lake Cachuma north of Santa Barbara so low: the ground is so dry that rain just gets absorbed and never makes it to the lake) or it might melt some unknown amount of snow causing the lake to rise by more than one inch.

    So I just built a very simple model.

    Hi Steve,

    Fair enough. Have just been reading articles and watching videos of the destruction of the Teton Dam in 1972. About two hours before the loss of the dam, a large whirlpool appeared a short distance in front of the dam. The fact that this, in conjunction with all the other problems, was still not enough for the authorities to admit that the dam was toast (and issue the appropriate warnings to the citizenry downstream) is a vivid practical illustration of the meaning of the word “denial”.

    Regards, Rob

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  68. @Almost Missouri

    "One large missile to that dam and it’s goodbye Egypt"
     
    Well, perhaps--if the missile is nuclear tipped. The Aswan Dam is a pretty thick embankment. You'd need a lot of conventional explosives to get through that.

    http://stranymira.com/uploads/posts/2008-07/1217076423_egypt.jpg

    Of course, the Israelis do have that (nukes, that is (as well as lots of conventionals.))

    It's been said that Israel is a "one nuke country" because it is so small, but it is less noted that Egypt may be a one nuke country as well, but for different reasons.

    Almost, In WWII the Brits had a dam busting bomb the was shaped like a 50 gallon drum. The bomb was to be dropped sidewise and skip across the dam lake and impact against the backside of the dam, intending to cause failure. I remember watching a doc about it, but I can’t remember if it was successfully deployed.

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    • Replies: @Austrian
    Two german dams were destroyed with rolling bombs:

    Secret german film of destroyed eder dam 1943

    The guy who filmed it was a soldier on vacation. Filming was banned under death penalty. He mandated that the footage can't be released until after his death. Apparently he wanted to be on the safe side, just in case the Nazis came back.

    , @RH
    Hello,

    The weapon certainly was successfully deployed. In "Operation Chastise" the Mohne and Eder dams were breached. The 1955 British film, "The Dambusters", not only follows the story pretty faithfully but is entertaining. You might also want to have a look at Barnes Wallis, the genius who conceived and designed the bouncing bomb.

    Cheers, RH
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  69. goatweed says:

    If the dam goes, how long to get 200,000 people out of Dodge?

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  70. Anonym says:
    @Steve Sailer
    A very large proportion of professional journalists were English majors in college.

    The ability to write quality prose fast is a talent that most people don't have. The ability to edit other people's prose might be even rarer.

    The ability to write quality prose fast is a talent that most people don’t have. The ability to edit other people’s prose might be even rarer.

    Now that I think about it, you are right re: ability to write quality prose, fast. It is uncommon. In terms of the top 2% or so in my graduating grade, none of us went into English as a major. It was all STEM. And as IQ would predict, we were all at or near the top of our class in English. We just chose more lucrative fields because we were also at the tops of our classes in math, physics, chem etc. But definitely the relatively innumerate journalist English major type exists, and is more common among women, and I would suspect due to the female brain thing, gay men.

    You obviously have more exposure to that world than I do. How many journalists would have the mathematical skills to be even a math teacher, let alone an engineer?

    Read More
    • Replies: @Steve Sailer
    Business / finance journalism is a good field for people who write fast and well and are comfortable around numbers.
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  71. Anonymous says: • Disclaimer

    >>>>Also the ‘emergency spillway’ — aka a hillside — is a joke

    >>>>Yes, calling that emergency outlet a “spillway” is hilarious.

    Behind my house — that is for sale — there’s a hillside. If I worked for the government I suppose it would occur to me to advertise the hillside as an additional auxiliary (emergency) bathroom. Or storage area. Or runway.

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  72. @Anonym
    The ability to write quality prose fast is a talent that most people don’t have. The ability to edit other people’s prose might be even rarer.

    Now that I think about it, you are right re: ability to write quality prose, fast. It is uncommon. In terms of the top 2% or so in my graduating grade, none of us went into English as a major. It was all STEM. And as IQ would predict, we were all at or near the top of our class in English. We just chose more lucrative fields because we were also at the tops of our classes in math, physics, chem etc. But definitely the relatively innumerate journalist English major type exists, and is more common among women, and I would suspect due to the female brain thing, gay men.

    You obviously have more exposure to that world than I do. How many journalists would have the mathematical skills to be even a math teacher, let alone an engineer?

    Business / finance journalism is a good field for people who write fast and well and are comfortable around numbers.

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    • Replies: @Anonym

    Business / finance journalism is a good field for people who write fast and well and are comfortable around numbers.
     
    Comfortable around arithmetic, yes. I think for a lot of these economist types, they are limited. Would they do, or think to do, the kind of analysis that any reasonable engineer should be able to do outside his field in a case such as this as you have done? If you can do it, it doesn't seem that hard. It's a fairly simple problem for an engineer, easily visualised, not involving much in the way of non-linearity that can't be approximated as linear.

    I have no doubt that you have the brains to be an engineer, for example. But there are a lot of accountants and finance types who break out in hives when it comes to trying to work out how something works in the physical world.
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  73. Austrian says:
    @Buffalo Joe
    Almost, In WWII the Brits had a dam busting bomb the was shaped like a 50 gallon drum. The bomb was to be dropped sidewise and skip across the dam lake and impact against the backside of the dam, intending to cause failure. I remember watching a doc about it, but I can't remember if it was successfully deployed.

    Two german dams were destroyed with rolling bombs:

    Secret german film of destroyed eder dam 1943

    The guy who filmed it was a soldier on vacation. Filming was banned under death penalty. He mandated that the footage can’t be released until after his death. Apparently he wanted to be on the safe side, just in case the Nazis came back.

    Read More
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  74. Anonym says:
    @Steve Sailer
    Business / finance journalism is a good field for people who write fast and well and are comfortable around numbers.

    Business / finance journalism is a good field for people who write fast and well and are comfortable around numbers.

    Comfortable around arithmetic, yes. I think for a lot of these economist types, they are limited. Would they do, or think to do, the kind of analysis that any reasonable engineer should be able to do outside his field in a case such as this as you have done? If you can do it, it doesn’t seem that hard. It’s a fairly simple problem for an engineer, easily visualised, not involving much in the way of non-linearity that can’t be approximated as linear.

    I have no doubt that you have the brains to be an engineer, for example. But there are a lot of accountants and finance types who break out in hives when it comes to trying to work out how something works in the physical world.

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    • Replies: @Steve Sailer
    I don't have good 3-d thinking skills. I can't think in 2-d terms pretty well, but there's a huge dropoff in performance when I have to switch from Flatland to Spaceland.

    Arithmetic will get you pretty far in a lot of businesses, especially the ability to multiply and divide approximately in your head while sitting around a conference table during a meeting.

    , @anon
    I'm told, by a reliable source, that in some of the toilets in the Medical Faculty Building at the University of Queensland, above the paper dispenser, were written these words:
    Engineering Degrees- please take one.
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  75. donut says:

    Steve , this is a job for William Langewiesche , post catastrophe , he is the best man to perform an autopsy . On the other hand , considering California’s current attitude towards the rest of the country I can only hope for a confluence of disasters : A major slip in the San Andreas Fault as well as the Cascadia Subduction zone giving way . I do hope that when it happens you are in the air on your way (with your family and your little bunny rabbit) to a meeting with Andrew Anglin to reestablish the Sturmabteilung . The time for any idiot moderation being long past . Tell me true : what’s wrong with being a racist and an Anti-Semite in 2017 ?

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  76. BDoyle says:
    @AnotherDad

    If the spillway failed over several hours it might be worth cutting a notch at the top of the dam. This would be risky, since the water might eat through crappy concrete and blow the whole dam. So save it for a last resort.
     
    Uh ... no!

    It's an earthfill dam. The one thing you don't want to do if have water running over the dam. That's the whole point of the "emergency spillway" is to have a outlet for overflow that does *not* send water over the top of the dam. (That's the whole point of spillways in general.)

    ~~~

    There are two points here:

    1) The emergency spillway is a genuine design failure--a genuine screwup of us dead white males. (Usually our stuff is pretty awesome and it's the disaster of modernity--letting women and leftists be in charge--that's the problem.)

    I've seen a lot of different spillways of various sorts. But the common element is that you get the water spilling *away* from critical structures. Often even on earthen dams there's a concrete lining on the critical section where water would be moving--potentially quickly--next to the dam structure. This always extends until the water is *away* from the dam and moving mostly *horizontally*. This dam has a concrete lip of 30' or so, creating a lot of force, but then doesn't have the landing area for that water reinforced. Worse the spilled water seems to have a "recollection" path--back near the primary spillway!--which is then subject to serious erosion. If they'd simply poured concrete running a couple hundred feet or so on down from the lip getting the water spread out and running parallel to the ground surface, any erosion would have been minimized and would have been far away from the structure that could be undermined.

    2) As i noted on the previous thread, the big question is what is the character of the rock under the regular spillway. If there's genuine 100 million year old Sierra Nevada granite ... the broken spillway is just dumping a lot of water into a rock canyon. No biggie. You can have it be a permanent feature. But if that hump of hill is just a pile of random aggregate, then blasting your 100,000 cfs down it, could serially eat out underneath the spillway eroding it back and back until you're eating away at the edge of the dam. Then you are in deep shit. It looks like there's a pretty massive piece of good rock in the flow near the break. But what is the rest of it like? With the water, i can't see what's there, what erosion is happening.

    The rock under the main spillway is not granite (unfortunately). It’s Mesozoic volcanics and meta-volcanics. From the picture I saw from when the spillway was empty, it seems to be a bit less resistant than the concrete itself.

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  77. In 1983 the Glenn Canyon Dam (Lake Powell) almost collapsed in a very similar scenario. Can you imagine? Lake Powell is immense compared to Oroville.

    A record 120,000 cfs was flowing into Lake Powell from late spring snow and rain in the Rocky Mountains that no one had anticipated. On July 2, the lake – considered full at 3700′ – was just 3.5 feet from its maximum capacity of 3711′ and rising three inches a day.

    The July 8 issue reported that the dam’s spillway began breaking up when officials upped the release to 92,000 cfs. The high velocity water was carving out huge holes in one of the tunnels, a process known as cavitation that sent chunks of concrete and red silt from the eroding Navajo sandstone bedrock shooting into the clear river below the dam.

    Officials at Glen Canyon dam quoted in the story admitted the spillways contained “known design flaws.” Averting a massive disaster became their priority. Meanwhile, the second spillway tunnel was beginning to suffer damage.

    http://www.hcn.org/40years/blog/the-summer-the-dam-almost-didnt

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    • Replies: @Steve Sailer
    Wow, Lake Powell behind Glen Canyon Dam in the upper Grand Canyon has a maximum volume 8 times Lake Oroville:

    LAKE POWELL WATER LEVELS. According to the National Park Service at Glen Canyon National Recreation area, storage of water at Lake Powell began March 13, 1963 and reached full pool (3,700 feet) the first time on June 22, 1980. Lake Powell's volume is 27,000,000 acre feet with a surface area of 266 square miles.

    , @Buck Turgidson
    I know some people who were there. In an effort to stop the dam from being overtopped (OM&#@$G), they used *plywood* to add a few extra feet to the dam height. Seemed to have worked.
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  78. @Bruce
    'It's an earthfill dam. The whole point of the spillway is to have water that does not go over the top of the dam.'

    Thanks.

    'The big question is the character of the rock under the regular spillway.'

    If I was dropping boulders from a helicopter into the hole, I'd use wire rope to hold them together. Let the energy of the water go into bouncing the boulders up and down and tangling themselves together, not into bouncing the boulders out of the hole. And I'd bolt wire ropes or I-beams to any visible rock under the spillway.

    “If I was dropping boulders from a helicopter into the hole, I’d use wire rope to hold them together. Let the energy of the water go into bouncing the boulders up and down and tangling themselves together, not into bouncing the boulders out of the hole.”

    That is a very good idea. Same sort of thing that makes the Hesco Bastion better protection than a pile of rocks and sand. Seeing that the holes are random-size and shape, how about a steel-cable mesh bag filled with rocks, that could be dropped in a hole and would then conform to the hole shape and not leave too many big voids? A flexible gabion. But you’d need a lot of steel for such a bag, so maybe drilling holes and threading the rocks on would be better? Hmm. Bag’s more elegant if you can make one. Make the bag from Kevlar or similar tough fibre, then link the bags together in situ? Wouldn’t rust like steel.

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

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    • Replies: @Bruce
    I'd never heard of Hesco Bastions. They look like a good thing to stuff into that hole. Maybe with wire rope loosely attaching them to bedrock, if you can find bedrock.

    And I'd put wire rope by itself in the hole, one end bolted to bedrock, one end loose. Let the random blasts of water pressure meet a wild hair of randomly whipping wire.

    If I had a really big air compressor just sitting there, it would be nice to blow the falling water away from the spillway. Make as much as possible fall into the river or at least land like hard rain, not like the raping trident marlinspike of Poseidon Ultor.
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  79. @ThreeCranes
    I have made this point before and I will again but some here will still argue with me. America's innumeracy and that of the press and even Steve's faltering explanation from a few days ago (through which he has finally fought to clarity) is exacerbated by our clumsy use of Olde English units of measure.

    Switching from acres to miles to cubic feet to inches per hour to gallons per minute to pounds pressure is very awkward because one is basically switching between number base systems. All this disappears in the metric system where volume and weight (and therefore pressure) are mutually related by--wait for it--the density of WATER!

    WELL WHAT DO YOU KNOW???? ONE WOULD ALMOST SUSPECT THAT THE GUYS WHO CAME UP WITH THAT SYSTEM HAD SOME INSIGHT INTO THE FUNDAMENTAL NATURE OF THINGS HERE FOR HUMANS ON EARTH!!!!

    And to top it off, they got rid of clumsy acres per square mile etc. and made everything multiples of ten, the same base as our number system.

    So, to reiterate, in the metric system clear thinking becomes much easier. And no, as potential commenters will no doubt argue, this is not an issue for ME PERSONALLY because I scored in the 99th percentile in math and general reasoning--which is the very reason I can see the confusion in the minds of those around me and is what enables me to recognize that it is a substantial issue for many of my struggling contemporaries.

    Steve's calculations are interesting but are not the whole story. He mentions that "As far as I can tell, the 14k cfs through the power station under the dam has been shut down for several days now, although I’ve read different explanations for why that is".

    As Unit472 in comment 23 says, pressure varies with depth and it may well be that the machinery or gates that regulate the flow of water to the turbines cannot handle the pressure created by the depth of water currently in the reservoir. A partially opened gate is subject to different cantilever-like torsional forces than one completely closed, so since pressure varies directly with depth, the gates or water wheels or whatever may not be able to handle the added pressure. Just speculating.

    But this brings up another issue. Steve related all this to the housing crisis and the thinking surrounding it. Very good. Now to the meat and potatoes.

    As Unit472 alluded to above, rate of flow is contingent upon pressure and pressure varies with depth. So, as water falls from sky, depth of water level rises and flow from orifice--not at overflow on surface, but orifice below surface--increases. If rate of increase in depth is faster than outflow then rate of outflow will not be constant but will increase with pressure. At some point, increased pressure will create increase velocity of outflow to the extent that inflow and outflow become equal--assuming system components can handle the pressure and flow. Krugman calls this economic instance of a related-rate problem "comparative advantage". A less efficient manufacturer can still make and export a product to a more efficient manufacturing nation if the two engage in frictionless trade because at some volume point any differential in cost per unit achieves equilibrium. This is fundamental reasoning behind globalism.

    But as Steve points out, there are pitfalls in reasoning from mathematical models and applying them to people and nationstates. Errors accumulate or rather cascade; the failure of one component--a rubber O ring for example--leads to failure of others until cataclysm. For just this reason, engineers design in huge safety margins and always try to err on the side of too much. Only in competitive sports is constant threat of breakage from expected use accepted, examples are masts of racing yachts and engines of Formula One cars.

    As banking has become more like a sport for the rich and less like a community investment designed like dams, i.e. major investments built to protect and enhance human quality and sacredness of life, breakage and ruin have become acceptable. Casino Wall Street no longer treats people as most valuable commodity and wants to dissolve the boundaries of the nation state which act as a bulwark against the vagaries of economic cycles just as a dam enables humans to regulate the seasonal flooding in a river and turn it into an communally-shared asset.

    "The Truth is the Whole" is not just a clever phrase.

    Only in competitive sports is constant threat of breakage from expected use accepted, examples are masts of racing yachts and engines of Formula One cars.

    Ferdinand Porsche once put it this way: If you construct a racing car, keep in mind that it doesn’t have to go futher than right over the finish line.
    Hmm
    You are taking Steve Sailer’s analogy between the dam-problems and the financial crisis a bit further:

    As banking has become more like a sport for the rich and less like a community investment designed like dams, i.e. major investments built to protect and enhance human quality and sacredness of life, breakage and ruin have become acceptable.

    -

    I’d like to add: The larger picture might well be, that banking as sports (of sorts) for the rich is directly related to your other thought: That this kind of new sporty banking is a hint at the other aspect that you mention: The sacredness of (communal) life – – -

    If this was right, it would show, that sports is simply not good enough as a value-source for society as a whole.

    Sports as the new cult (in the place of religion) – might just not be complex enough to really fullfill the functions that religion once fullfilled.

    This might be part of an explanation, why those bankers and hedgers etc. always got away – and still get away – with their insane profits: Because the public, more and more obsessed with winners and losers (= sports) – is somewhat disarmed – morally or ethically disarmed, so to speak, as soon as sports step in as the new big paradigm of how things should be handled just and well.

    - Religion was (is) much more complex than sports: There’s so much more than winners and losers – and all that is simply lost, if secularisation is taken too easily – – – without Max Weber – without Kant and Mill and Wittgenstein (etc.).

    By the way: Kant and Wittgenstein – and Fromm and Habermas – none o them said, that they’d be replacing religion – or that you should replace the Judeo-Christian tradition, even. – BE CAREFUL WITH THAT AXE, EUGINE – to paraphrase Pink Floyd…

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    • Replies: @ThreeCranes
    And you took what I said to the next level with your thought provoking observations on sports/religion as models of life. So true that "there's so much more than winners and loser--and all that is simply lost....".
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  80. RH says:
    @Buffalo Joe
    Almost, In WWII the Brits had a dam busting bomb the was shaped like a 50 gallon drum. The bomb was to be dropped sidewise and skip across the dam lake and impact against the backside of the dam, intending to cause failure. I remember watching a doc about it, but I can't remember if it was successfully deployed.

    Hello,

    The weapon certainly was successfully deployed. In “Operation Chastise” the Mohne and Eder dams were breached. The 1955 British film, “The Dambusters”, not only follows the story pretty faithfully but is entertaining. You might also want to have a look at Barnes Wallis, the genius who conceived and designed the bouncing bomb.

    Cheers, RH

    Read More
    • Replies: @Buffalo Joe
    RH, Yes, thank you, bouncing bombs and all that. Just kidding, Cheers to you to.
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  81. Glaivester says: • Website
    @dearieme
    The first non-stop flight across the Atlantic happened in a plane equipped with two Rolls-Royce Eagle 360 hp engines.

    "Charles also said “America First.” He was right about that too." Not in the context of the first non-stop flight across the Atlantic, he wasn't.

    It was the first non-stop SOLO flight across the Atlantic. I believe it was the fourth non-stop flight in all, and the sixty-seventh person to go across (the previous three flights held a total of 66 people).

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  82. Glaivester says: • Website
    @dearieme
    What an extraordinarily long-winded way to avoid the point that the argument against twin engines was utter twaddle.

    It doesn’t make the argument twaddle. The fact that people succeeded with twin engines does not mean that it was less risky.

    Ultimately, I would think that all else being equal, it would be better to be in a single-engine plane than in a twin-engine plane that required both engines to be working to fly. A twin-engine plane is better if the plane can get by with only one engine if need be.

    Read More
    • Replies: @Whoever

    A twin-engine plane is better if the plane can get by with only one engine if need be.
     
    When a modern light twin loses an engine, it loses 80 percent of its calculated climb performance, due to the increased drag and loss of power required for a climb. The actual weight of the aircraft (fuel load, passengers, cargo) and its altitude may push that into the negative. For vintage aircraft, with generally less engine power and more drag than modern designs, the airplane is going down, no question about it.
    Even most modern propeller-driven twins can't stay airborne with only one engine. At best they can achieve a managed decent, but the thrust imbalance makes even that really hard.
    When an engine fails on a prop plane, a torque develops from the center of gravity to the thrust vector of the operating engine, multiplied by the thrust of the operating engine.
    This torque is worse on aircraft with both propellers turning clockwise when viewed from astern -- as is typically the case -- if the left engine fails, because asymmetric propeller blade effect causes the right-hand engine to develops its thrust vector farther from the aircraft's center of gravity than the left-hand engine. The result is yawing so severe it may exceed the authority of the control surfaces and the aircraft will go into an unrecoverable spin.
    You have to manage that, if you can (you will be in a side-slip that your ball won't reveal), using rudder and ailerons, at the same time that you may be riding a stall, as well as managing the decent and looking for someplace comfortable to hit.
    Lindbergh was absolutely right to chose a single-engine aircraft for his North Atlantic crossing. No fool, he also used a single-engine Lockheed Sirius for his South Atlantic and North Pacific crossings.
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  83. johnmark7 says:
    @Sunbeam
    Not much to add to this.

    I would like to point out that this country has an awful lot of big public works that were completed in days gone by (up to a century for a number of them).

    They were built for a reason, and they accomplished their purpose. However nothing lasts forever, and eventually you have to put some major work into things like this.

    Granted this particular incident is an unusual amount of rainfall, but I read an article or two a few years ago about the poor condition of the water works in California particularly in the Northern section. This made me think of this.

    There there is the "Man vs. Nature" fight of the Army Corp of Engineers keeping the river flowing by New Orleans instead of where it seems to want to go. One day they lose that one.

    Seems a lot harder for us to build big stuff than it was back in the day. Regulations (some of them good actually; there are a lot of 19th century retaining ponds and waterworks that have come apart at the seams over the last few decades) are a part of it of course.

    But geez imagine them building the Golden Gate Bridge now. You just thought the Big Dig took forever.

    I’ve been in Sacramento since 1986. This is the third time we’ve had an “unusual” amount of rainfall. 3 in 30 years seems fairly frequent to me as this SFGate article also explains:

    http://www.sfgate.com/bayarea/article/California-due-for-biblical-flooding-arkstorm-10921370.php

    If your area had a major earthquake every ten years, you might build your home even more diligently as someone else said – penny wise, pound foolish.

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    • Replies: @Steve Sailer
    All that happened was that the last rain storm got stuck over the watershed and dumped about 3.5 inches in three days ... while the main spillway was broken and the powerhouse outlet was backed up.

    I'm guessing that up to February 7th or so, the management was trying to come close to filling the reservoir to the brim due to the previous drought and concerns about global warming causing more droughts. It looked like they were trying to keep the reservoir 50 feet below the rim through the rains of February 2 to 6th, even though they had to know there was a lot of water already on the ground in the watershed and headed toward the reservoir.

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  84. @johnmark7
    I've been in Sacramento since 1986. This is the third time we've had an "unusual" amount of rainfall. 3 in 30 years seems fairly frequent to me as this SFGate article also explains:

    http://www.sfgate.com/bayarea/article/California-due-for-biblical-flooding-arkstorm-10921370.php

    If your area had a major earthquake every ten years, you might build your home even more diligently as someone else said - penny wise, pound foolish.

    All that happened was that the last rain storm got stuck over the watershed and dumped about 3.5 inches in three days … while the main spillway was broken and the powerhouse outlet was backed up.

    I’m guessing that up to February 7th or so, the management was trying to come close to filling the reservoir to the brim due to the previous drought and concerns about global warming causing more droughts. It looked like they were trying to keep the reservoir 50 feet below the rim through the rains of February 2 to 6th, even though they had to know there was a lot of water already on the ground in the watershed and headed toward the reservoir.

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  85. @George Taylor
    In 1983 the Glenn Canyon Dam (Lake Powell) almost collapsed in a very similar scenario. Can you imagine? Lake Powell is immense compared to Oroville.

    A record 120,000 cfs was flowing into Lake Powell from late spring snow and rain in the Rocky Mountains that no one had anticipated. On July 2, the lake - considered full at 3700' - was just 3.5 feet from its maximum capacity of 3711' and rising three inches a day.

    The July 8 issue reported that the dam's spillway began breaking up when officials upped the release to 92,000 cfs. The high velocity water was carving out huge holes in one of the tunnels, a process known as cavitation that sent chunks of concrete and red silt from the eroding Navajo sandstone bedrock shooting into the clear river below the dam.

    Officials at Glen Canyon dam quoted in the story admitted the spillways contained "known design flaws." Averting a massive disaster became their priority. Meanwhile, the second spillway tunnel was beginning to suffer damage.
     
    http://www.hcn.org/40years/blog/the-summer-the-dam-almost-didnt

    Wow, Lake Powell behind Glen Canyon Dam in the upper Grand Canyon has a maximum volume 8 times Lake Oroville:

    LAKE POWELL WATER LEVELS. According to the National Park Service at Glen Canyon National Recreation area, storage of water at Lake Powell began March 13, 1963 and reached full pool (3,700 feet) the first time on June 22, 1980. Lake Powell’s volume is 27,000,000 acre feet with a surface area of 266 square miles.

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  86. @RH
    Hello,

    The weapon certainly was successfully deployed. In "Operation Chastise" the Mohne and Eder dams were breached. The 1955 British film, "The Dambusters", not only follows the story pretty faithfully but is entertaining. You might also want to have a look at Barnes Wallis, the genius who conceived and designed the bouncing bomb.

    Cheers, RH

    RH, Yes, thank you, bouncing bombs and all that. Just kidding, Cheers to you to.

    Read More
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  87. @Anonym

    Business / finance journalism is a good field for people who write fast and well and are comfortable around numbers.
     
    Comfortable around arithmetic, yes. I think for a lot of these economist types, they are limited. Would they do, or think to do, the kind of analysis that any reasonable engineer should be able to do outside his field in a case such as this as you have done? If you can do it, it doesn't seem that hard. It's a fairly simple problem for an engineer, easily visualised, not involving much in the way of non-linearity that can't be approximated as linear.

    I have no doubt that you have the brains to be an engineer, for example. But there are a lot of accountants and finance types who break out in hives when it comes to trying to work out how something works in the physical world.

    I don’t have good 3-d thinking skills. I can’t think in 2-d terms pretty well, but there’s a huge dropoff in performance when I have to switch from Flatland to Spaceland.

    Arithmetic will get you pretty far in a lot of businesses, especially the ability to multiply and divide approximately in your head while sitting around a conference table during a meeting.

    Read More
    • Replies: @newrouter
    "I don’t have good 3-d thinking skills."

    You have "common sense".

    Here's some 2-D with water and dams:

    http://rivers.bee.oregonstate.edu/sites/default/files/imagecache/module/1996_new_years_flood_drawn.png
    , @Jim Don Bob
    Yeah, It amazes me how many people can't multiply something like 26 X 315 in their head and even get into the right order of magnitude. 3 times 26 plus some zeros and you are there.
    , @Anonym
    I think you undersell yourself, as you are dealing with volumes here, which are inherently 3d. Although it's a fairly easy 3d shape, you still remark that the reservoir is shaped like a funnel and that has ramifications re: volume vs vs water depth below maximum being non-linear. You also grasp the area of catchment, the rainfall flux, the idea that something less than 100% of the rainfall must enter the reservoir. And that conservation of mass should apply, ignoring evaporation. So water mass = initial water mass plus outflow less inflow.

    With no background, I think you've already entered high school extra credit physics type work. It's funny that in college engineering work, there is that moment to put on the big boy pants. What once was extra credit and worth a pat on the back becomes the expected - either do it, and do it right, or fail. Someone who is capable of understanding the physical world and getting it right, i.e. an engineer or someone who could succeed as an engineer, will be able to look at a novel situation such as this and get it right most of the time.

    We need more people who are capable of this sort of thought running the country, engaging in the debates, and shaping the debates. Proposed systems need to work. This is something China gets right, with the numbers of engineers in government. Though broader experience than engineering is also needed.
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  88. @Dieter Kief

    Only in competitive sports is constant threat of breakage from expected use accepted, examples are masts of racing yachts and engines of Formula One cars.
     
    Ferdinand Porsche once put it this way: If you construct a racing car, keep in mind that it doesn't have to go futher than right over the finish line.
    Hmm
    You are taking Steve Sailer's analogy between the dam-problems and the financial crisis a bit further:

    As banking has become more like a sport for the rich and less like a community investment designed like dams, i.e. major investments built to protect and enhance human quality and sacredness of life, breakage and ruin have become acceptable.
     
    -

    I'd like to add: The larger picture might well be, that banking as sports (of sorts) for the rich is directly related to your other thought: That this kind of new sporty banking is a hint at the other aspect that you mention: The sacredness of (communal) life - - -

    If this was right, it would show, that sports is simply not good enough as a value-source for society as a whole.

    Sports as the new cult (in the place of religion) - might just not be complex enough to really fullfill the functions that religion once fullfilled.

    This might be part of an explanation, why those bankers and hedgers etc. always got away - and still get away - with their insane profits: Because the public, more and more obsessed with winners and losers (= sports) - is somewhat disarmed - morally or ethically disarmed, so to speak, as soon as sports step in as the new big paradigm of how things should be handled just and well.

    - Religion was (is) much more complex than sports: There's so much more than winners and losers - and all that is simply lost, if secularisation is taken too easily - - - without Max Weber - without Kant and Mill and Wittgenstein (etc.).

    By the way: Kant and Wittgenstein - and Fromm and Habermas - none o them said, that they'd be replacing religion - or that you should replace the Judeo-Christian tradition, even. - BE CAREFUL WITH THAT AXE, EUGINE - to paraphrase Pink Floyd...

    And you took what I said to the next level with your thought provoking observations on sports/religion as models of life. So true that “there’s so much more than winners and loser–and all that is simply lost….”.

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  89. newrouter says:
    @ThreeCranes
    I have made this point before and I will again but some here will still argue with me. America's innumeracy and that of the press and even Steve's faltering explanation from a few days ago (through which he has finally fought to clarity) is exacerbated by our clumsy use of Olde English units of measure.

    Switching from acres to miles to cubic feet to inches per hour to gallons per minute to pounds pressure is very awkward because one is basically switching between number base systems. All this disappears in the metric system where volume and weight (and therefore pressure) are mutually related by--wait for it--the density of WATER!

    WELL WHAT DO YOU KNOW???? ONE WOULD ALMOST SUSPECT THAT THE GUYS WHO CAME UP WITH THAT SYSTEM HAD SOME INSIGHT INTO THE FUNDAMENTAL NATURE OF THINGS HERE FOR HUMANS ON EARTH!!!!

    And to top it off, they got rid of clumsy acres per square mile etc. and made everything multiples of ten, the same base as our number system.

    So, to reiterate, in the metric system clear thinking becomes much easier. And no, as potential commenters will no doubt argue, this is not an issue for ME PERSONALLY because I scored in the 99th percentile in math and general reasoning--which is the very reason I can see the confusion in the minds of those around me and is what enables me to recognize that it is a substantial issue for many of my struggling contemporaries.

    Steve's calculations are interesting but are not the whole story. He mentions that "As far as I can tell, the 14k cfs through the power station under the dam has been shut down for several days now, although I’ve read different explanations for why that is".

    As Unit472 in comment 23 says, pressure varies with depth and it may well be that the machinery or gates that regulate the flow of water to the turbines cannot handle the pressure created by the depth of water currently in the reservoir. A partially opened gate is subject to different cantilever-like torsional forces than one completely closed, so since pressure varies directly with depth, the gates or water wheels or whatever may not be able to handle the added pressure. Just speculating.

    But this brings up another issue. Steve related all this to the housing crisis and the thinking surrounding it. Very good. Now to the meat and potatoes.

    As Unit472 alluded to above, rate of flow is contingent upon pressure and pressure varies with depth. So, as water falls from sky, depth of water level rises and flow from orifice--not at overflow on surface, but orifice below surface--increases. If rate of increase in depth is faster than outflow then rate of outflow will not be constant but will increase with pressure. At some point, increased pressure will create increase velocity of outflow to the extent that inflow and outflow become equal--assuming system components can handle the pressure and flow. Krugman calls this economic instance of a related-rate problem "comparative advantage". A less efficient manufacturer can still make and export a product to a more efficient manufacturing nation if the two engage in frictionless trade because at some volume point any differential in cost per unit achieves equilibrium. This is fundamental reasoning behind globalism.

    But as Steve points out, there are pitfalls in reasoning from mathematical models and applying them to people and nationstates. Errors accumulate or rather cascade; the failure of one component--a rubber O ring for example--leads to failure of others until cataclysm. For just this reason, engineers design in huge safety margins and always try to err on the side of too much. Only in competitive sports is constant threat of breakage from expected use accepted, examples are masts of racing yachts and engines of Formula One cars.

    As banking has become more like a sport for the rich and less like a community investment designed like dams, i.e. major investments built to protect and enhance human quality and sacredness of life, breakage and ruin have become acceptable. Casino Wall Street no longer treats people as most valuable commodity and wants to dissolve the boundaries of the nation state which act as a bulwark against the vagaries of economic cycles just as a dam enables humans to regulate the seasonal flooding in a river and turn it into an communally-shared asset.

    "The Truth is the Whole" is not just a clever phrase.

    “in the metric system clear thinking becomes much easier.”

    Yes Merkel’s Germany has much “clear thinking”.

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    • Replies: @Steve Sailer
    The metric system is better.
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  90. @newrouter
    "in the metric system clear thinking becomes much easier."

    Yes Merkel's Germany has much "clear thinking".

    The metric system is better.

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    • Replies: @newrouter
    "The metric system is better."


    Mathematically better. But overall, like saying Esperanto is better than English.
    , @newrouter
    "The metric system is better."

    Who determines what is "better"? The French metric system is a spinoff of their revolution. It has been that system that has been foisted upon the world. So you have French vs English/American
    measurement fighting for control of measuring things.

    , @BB753
    Had there been a second Carter presidential term, America would have gone metric, or so the legend goes. Canada did go metric in the late seventies, with both systems still in use, which makes for a smooth transition.
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  91. anon says: • Disclaimer
    @Anonym

    Business / finance journalism is a good field for people who write fast and well and are comfortable around numbers.
     
    Comfortable around arithmetic, yes. I think for a lot of these economist types, they are limited. Would they do, or think to do, the kind of analysis that any reasonable engineer should be able to do outside his field in a case such as this as you have done? If you can do it, it doesn't seem that hard. It's a fairly simple problem for an engineer, easily visualised, not involving much in the way of non-linearity that can't be approximated as linear.

    I have no doubt that you have the brains to be an engineer, for example. But there are a lot of accountants and finance types who break out in hives when it comes to trying to work out how something works in the physical world.

    I’m told, by a reliable source, that in some of the toilets in the Medical Faculty Building at the University of Queensland, above the paper dispenser, were written these words:
    Engineering Degrees- please take one.

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    • Replies: @Dan Hayes
    anon:

    Here's another one. Inscribed on top of one of the urinals in Columbia University's Physics Building was the immortal phrase "Enrico Fermi pi..ed here".
    , @Anonym
    Tell that to Xi Jinping.

    If you artificially restricted entrance to engineering schools like they do medicine, then engineers would be paid more. Still they are paid well.
    , @Anonym
    Where is the doctor equivalent of Carlos Slim? When it comes to earning potential at the high end for engineers and their companies, the dick waving competition comes out in favor of the engineer. That's a nice Maserati doctor, would you like to take a ride in my gulfstream?

    https://youtu.be/sr9_GfeoCjk
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  92. newrouter says:
    @Steve Sailer
    I don't have good 3-d thinking skills. I can't think in 2-d terms pretty well, but there's a huge dropoff in performance when I have to switch from Flatland to Spaceland.

    Arithmetic will get you pretty far in a lot of businesses, especially the ability to multiply and divide approximately in your head while sitting around a conference table during a meeting.

    “I don’t have good 3-d thinking skills.”

    You have “common sense”.

    Here’s some 2-D with water and dams:

    Read More
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  93. newrouter says:
    @Steve Sailer
    The metric system is better.

    “The metric system is better.”

    Mathematically better. But overall, like saying Esperanto is better than English.

    Read More
    • Replies: @Anonym
    No, the metric system is definitely better for anyone who does anything involving physics or engineering as a living. It is designed to make sense and be easy to use from the beginning, instead of being an amalgamation of different medieval units and measures. That's why everyone but the USA and two other countries have adopted the metric system. The others are Liberia and Burma - real world leaders there. And Burma is taking steps to adopt it officially. So basically there is the US... and Liberia.

    That even with all the USA's might and soft power, they can't convince the rest of the world to embrace its stupid system. And attend a US college - you will find that in technical subjects metric is used. Even the USA uses metric in many applications.

    So, if everyone in the world spoke Esperanto, yes, Metric would be like it.
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  94. Hibernian says:
    @candid_observer
    Probably the best way to calculate the probability that a system will fail is not to look at the components of the system, but rather at the components of the organizations which made it: what are their incentives to cheat?

    One hopes that the civil engineers involved in constructing the dam had fewer incentives to cut corners than the financial engineers behind the housing bubble.

    Never trust a contractor.

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  95. newrouter says:
    @Steve Sailer
    The metric system is better.

    “The metric system is better.”

    Who determines what is “better”? The French metric system is a spinoff of their revolution. It has been that system that has been foisted upon the world. So you have French vs English/American
    measurement fighting for control of measuring things.

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  96. @Steve Sailer
    I don't have good 3-d thinking skills. I can't think in 2-d terms pretty well, but there's a huge dropoff in performance when I have to switch from Flatland to Spaceland.

    Arithmetic will get you pretty far in a lot of businesses, especially the ability to multiply and divide approximately in your head while sitting around a conference table during a meeting.

    Yeah, It amazes me how many people can’t multiply something like 26 X 315 in their head and even get into the right order of magnitude. 3 times 26 plus some zeros and you are there.

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  97. The medium-range forecast for the Oroville area discussed at Anthony Watts’s website does not look good: LINK. There’s the potential for 10+ inches of precipitation over the 10 days or so.

    Of course how much of it falls as snow on the watershed’s higher elevations will make a big difference.

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  98. Krollchem says:

    Steve,

    The 4.75 inches over the subsequent 8 days refers to the city of Oroville, not the higher elevation watershed. The Lake Oroville watershed is estimated to get 11.62 inches of rain over the next 10 days. Initially this will be in the form of rain, but will later turn to snow (several feet) at the higher elevations:

    https://wattsupwiththat.com/2017/02/15/super-soaker-atmospheric-river-taking-aim-on-beleaguered-orovilledam/

    A poster, Willis Eschenbach, ran the numbers as follows:
    February 15, 2017 at 1:00 pm

    OK … Lake Oroville watershed area 3611 mi2
    Lake surface area 25 mi2
    Current head space at 6 am Feb 15th (today) 22 feet
    Predicted rain 11+ inches
    So … figure maybe 90% of the rain makes it to the lake. Call it 10″. Concentrated by 3611 / 25 = 144 to 1 (The snow accumulation will reduce the runoff somewhat)
    So that’s about 144 times 10 inches, 1440 inches or about 120 feet. Yikes. However, we already have 22 feet of headspace (freeboard).
    Now, the spillway is losing 100,000 cubic feet per second.
    Total volume = 10 inches * 3611 square miles = 83.9E+9 cubic feet
    Time to drain it all = 83.9E+9 / 1E+5 =839000 seconds = 9.7 days * 5/6 (because of headspace) = 8 days

    Gonna be tight … very tight. Obviously, this is back of the envelope, but it’s not a clear win for the good guys …

    Another poster cautioned: “Melt season generally starts around 1 April. The worst possible scenario would be a warm storm system in late March or early April that melts a lot of the snow pack all at once.”

    Graphics and additional info at:

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

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  99. 10 inches of rain is 120 feet of rise in the reservoir, assuming no snow, no melting of snow, and no absorption into the ground, and continuing to be able to send 100k cfs down the main spillway.

    Over ten days they can lower the lake level maybe 80 feet down the main spillway. By midnight they’ll have about 27 feet of to play with, so that would be 13 feet over the brim. Also, rain takes a day or two to move into the reservoir so if after ten days of rain they get some dry weather, then then have, say, an extra day and a half to dump water, so that’s an additional 12 feet over 11.5 days, or the lake being one foot over the brim.

    It would be really, really helpful to get the 14k cfs powerplant working again to add about a foot or more of drainage per day.

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    • Replies: @The Last Real Calvinist
    I hope and pray this is about right.

    Roy Spencer, also on the weather-expert side of things, is also guardedly optimistic: LINK.

    He seems to be counting on most of the precipitation in the watershed indeed falling as snow, and therefore staying put throughout the wet period.

    , @Krollchem
    The powerhouse you mention is disconnected from the grid and the generators cannot be run without their output being distributed. Apparently, even if the lines were connected they couldn’t run the turbines full power at the moment anyway. Seems that the water level at the base of the power station has been elevated by all the debris that has washed down into the river and the turbines won’t work efficiently if their outlets are not above water.

    Fortunately, in addition to the snowfall component reducing the freeboard issues, it is very unlikely that the 11.62″ will fall over the whole catchment basin. I expect that these factors will avert a disaster.

    A good visualization of the atmospheric river (you can scroll it forward in time) can be found at: https://earth.nullschool.net/#current/wind/surface/level/overlay=total_precipitable_water/orthographic=-128.96,32.80,2171/loc=-143.612,25.806
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  100. Read an article in the Sacramento Bee, they are all giddy. They claim that a Black Hawk helicopter is ferrying stone to fill the void and that a convoy of trucks is bring 1200 tons of rock per hour. Another fail at simple math. Large dump truck, not the earth moving kind, can safely carry 20 tons of stone per load, but that would be gravel or crushed stone, not random sized boulders. This would be 60 trucks per hour or one per minute, arrive, dump and go to reload…it would look like a line of ants at a picnic. Hope all goes well though.

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  101. Dan Hayes says:
    @anon
    I'm told, by a reliable source, that in some of the toilets in the Medical Faculty Building at the University of Queensland, above the paper dispenser, were written these words:
    Engineering Degrees- please take one.

    anon:

    Here’s another one. Inscribed on top of one of the urinals in Columbia University’s Physics Building was the immortal phrase “Enrico Fermi pi..ed here”.

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  102. Whoever says:
    @Glaivester
    It doesn't make the argument twaddle. The fact that people succeeded with twin engines does not mean that it was less risky.

    Ultimately, I would think that all else being equal, it would be better to be in a single-engine plane than in a twin-engine plane that required both engines to be working to fly. A twin-engine plane is better if the plane can get by with only one engine if need be.

    A twin-engine plane is better if the plane can get by with only one engine if need be.

    When a modern light twin loses an engine, it loses 80 percent of its calculated climb performance, due to the increased drag and loss of power required for a climb. The actual weight of the aircraft (fuel load, passengers, cargo) and its altitude may push that into the negative. For vintage aircraft, with generally less engine power and more drag than modern designs, the airplane is going down, no question about it.
    Even most modern propeller-driven twins can’t stay airborne with only one engine. At best they can achieve a managed decent, but the thrust imbalance makes even that really hard.
    When an engine fails on a prop plane, a torque develops from the center of gravity to the thrust vector of the operating engine, multiplied by the thrust of the operating engine.
    This torque is worse on aircraft with both propellers turning clockwise when viewed from astern — as is typically the case — if the left engine fails, because asymmetric propeller blade effect causes the right-hand engine to develops its thrust vector farther from the aircraft’s center of gravity than the left-hand engine. The result is yawing so severe it may exceed the authority of the control surfaces and the aircraft will go into an unrecoverable spin.
    You have to manage that, if you can (you will be in a side-slip that your ball won’t reveal), using rudder and ailerons, at the same time that you may be riding a stall, as well as managing the decent and looking for someplace comfortable to hit.
    Lindbergh was absolutely right to chose a single-engine aircraft for his North Atlantic crossing. No fool, he also used a single-engine Lockheed Sirius for his South Atlantic and North Pacific crossings.

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  103. @Steve Sailer
    10 inches of rain is 120 feet of rise in the reservoir, assuming no snow, no melting of snow, and no absorption into the ground, and continuing to be able to send 100k cfs down the main spillway.

    Over ten days they can lower the lake level maybe 80 feet down the main spillway. By midnight they'll have about 27 feet of to play with, so that would be 13 feet over the brim. Also, rain takes a day or two to move into the reservoir so if after ten days of rain they get some dry weather, then then have, say, an extra day and a half to dump water, so that's an additional 12 feet over 11.5 days, or the lake being one foot over the brim.

    It would be really, really helpful to get the 14k cfs powerplant working again to add about a foot or more of drainage per day.

    I hope and pray this is about right.

    Roy Spencer, also on the weather-expert side of things, is also guardedly optimistic: LINK.

    He seems to be counting on most of the precipitation in the watershed indeed falling as snow, and therefore staying put throughout the wet period.

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  104. Here’s the forecast for Feather Falls, CA, which is up a ways in the mountains at 2,900 feet elevation.

    https://www.wunderground.com/us/ca/feather-falls

    It usually gets more rain than Oroville which is lower and warmer just before you get to the Sierra.

    That’s a lot of precipitation forecast for Feather Falls. Most will fall on Feather Falls as rain, although looking out 9 days, it might be snow.

    Temperatures decline about 3.6 degrees per 1000 feet of elevation.

    I don’t know what the average height of the watershed is. The Sierras aren’t super high that far north, so I’d guess about 6,000 feet. So, at 6000 feet, it will be about 11 degrees cooler than Feather Falls at 3,000 feet. I’m guessing average temperatures at 6,000 feet for the next few days of around 33 degrees. Will that be rain or snow?

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  105. What I learned from this post:

    Even when he thinks about stuff that I’m good at thinking about, Steve is better at thinking about it than I am.

    I enjoy nothing more than being in a room with people who are smarter than I am. I mean that sincerely – this blog is a treasure.

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  106. Krollchem says:
    @Steve Sailer
    10 inches of rain is 120 feet of rise in the reservoir, assuming no snow, no melting of snow, and no absorption into the ground, and continuing to be able to send 100k cfs down the main spillway.

    Over ten days they can lower the lake level maybe 80 feet down the main spillway. By midnight they'll have about 27 feet of to play with, so that would be 13 feet over the brim. Also, rain takes a day or two to move into the reservoir so if after ten days of rain they get some dry weather, then then have, say, an extra day and a half to dump water, so that's an additional 12 feet over 11.5 days, or the lake being one foot over the brim.

    It would be really, really helpful to get the 14k cfs powerplant working again to add about a foot or more of drainage per day.

    The powerhouse you mention is disconnected from the grid and the generators cannot be run without their output being distributed. Apparently, even if the lines were connected they couldn’t run the turbines full power at the moment anyway. Seems that the water level at the base of the power station has been elevated by all the debris that has washed down into the river and the turbines won’t work efficiently if their outlets are not above water.

    Fortunately, in addition to the snowfall component reducing the freeboard issues, it is very unlikely that the 11.62″ will fall over the whole catchment basin. I expect that these factors will avert a disaster.

    A good visualization of the atmospheric river (you can scroll it forward in time) can be found at: https://earth.nullschool.net/#current/wind/surface/level/overlay=total_precipitable_water/orthographic=-128.96,32.80,2171/loc=-143.612,25.806

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    • Replies: @Steve Sailer
    Thanks.

    The main spillway explosion dumped a lot of debris into the river, which partially dammed the river, raising the water level, blocking the power plant from operating.

    And the erosion around the main spillway threatened to undermine the power towers so they took down the power cables via helicopter.

    So they have to fix both problems by dredging the river and by moving the power towers higher up and restringing the wires to get the power station working again.

    That's a lot of work.
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  107. anon says: • Disclaimer
    @Buck Turgidson
    Steve You are getting close to my wheelhouse to the extent I might have one. The decision guidance that reservoir operators use for operational and release decisions is known as a "rule curve." It provides guidance for variables like reservoir storage level, time of year, etc. So on Feb 1, the rule curve helps determine appropriate reservoir level/storage capacity and outflow for that date, all of which should be within given ranges. Rule curves get updated in order to reflect changes in land cover, runoff, and yes climate. I never have run a dam or calculated a rule curve, but I believe it allows for some judgement and wiggle room. I can't describe the flood control-storage balance any better than Steve did (releases in Feb vs storage in August).

    You have a lot of readers with good comments. This is not the first time this has happened out West and there is in fact a history of it. A good example was @ Glen Canyon Dam in 1983. Given all the interest, readers may be interested in this article:

    http://www.colorado.edu/geography/geomorph/envs_5810/rhodes_84.pdf

    Something similar happened w the Army Corps of Engineers and its big Missouri River storage system in 2011

    Interesting. Especially the fact that optimizing storage increases risk of flood control — the other rationale of the system.

    Who/Whom.

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  108. So, to reiterate, in the metric system clear thinking becomes much easier. And no, as potential commenters will no doubt argue, this is not an issue for ME PERSONALLY because I scored in the 99th percentile in math and general reasoning–which is the very reason I can see the confusion in the minds of those around me and is what enables me to recognize that it is a substantial issue for many of my struggling contemporaries.

    Three Brains:

    Are you also a MENSA member with a proven IQ of 500 who has been an authentic jazzman for the last 80 years?

    Here’s some questions:

    Suppose there are two man-made reservoirs, both full of water. Both are round, both have flat bottoms with a depth of 100 meters. One reservoir is 100 meters in diameter. The other reservoir is one kilometer in diameter. Suppose a hole one meter in diameter is opened at the bottom of both of the two reservoirs, from which water is free to drain into the ambient air. Assume the surfaces of both reservoirs are 100 meters above sea level.

    (1) What will the water pressure be at the hole at the bottom of the 100 meter diameter reservoir?

    (2) What will the water pressure be at the hole at the bottom of the 1 kilometer diameter reservoir?

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    • Replies: @Hippopotamusdrome
    1. 160 pounds per square inch
    2. 2998 inches of mercury
    , @Austrian

    Suppose there are two man-made reservoirs, both full of water. Both are round, both have flat bottoms with a depth of 100 meters. One reservoir is 100 meters in diameter. The other reservoir is one kilometer in diameter. Suppose a hole one meter in diameter is opened at the bottom of both of the two reservoirs, from which water is free to drain into the ambient air. Assume the surfaces of both reservoirs are 100 meters above sea level.

    (1) What will the water pressure be at the hole at the bottom of the 100 meter diameter reservoir?

    (2) What will the water pressure be at the hole at the bottom of the 1 kilometer diameter reservoir?
     

    ~10 bar in both cases. This is not a good IQ test. Any plumber would know the answer. Many Geniuses who are illiterate in physics on the other hand would not.

    @Steve Sailer
    They should build a giant immersion heater. Throw some pipe into the reservoir. Connect it to the power station. A galvanic anode would be needed to prevent corrosion. Aluminum would do the trick.

    , @Jim Don Bob
    The same.
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  109. @Krollchem
    The powerhouse you mention is disconnected from the grid and the generators cannot be run without their output being distributed. Apparently, even if the lines were connected they couldn’t run the turbines full power at the moment anyway. Seems that the water level at the base of the power station has been elevated by all the debris that has washed down into the river and the turbines won’t work efficiently if their outlets are not above water.

    Fortunately, in addition to the snowfall component reducing the freeboard issues, it is very unlikely that the 11.62″ will fall over the whole catchment basin. I expect that these factors will avert a disaster.

    A good visualization of the atmospheric river (you can scroll it forward in time) can be found at: https://earth.nullschool.net/#current/wind/surface/level/overlay=total_precipitable_water/orthographic=-128.96,32.80,2171/loc=-143.612,25.806

    Thanks.

    The main spillway explosion dumped a lot of debris into the river, which partially dammed the river, raising the water level, blocking the power plant from operating.

    And the erosion around the main spillway threatened to undermine the power towers so they took down the power cables via helicopter.

    So they have to fix both problems by dredging the river and by moving the power towers higher up and restringing the wires to get the power station working again.

    That’s a lot of work.

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    • Replies: @Hodag
    Couldn't they just run a set of wires 3000 feet in the opposite direction, drive an iron rod to bedrock and ground it?
    , @Krollchem
    Perhaps more good luck for the engineers who are trying to fix this political mess is on the way. It appears that the atmospheric river is being pushed further South toward LA:

    https://earth.nullschool.net/#current/wind/surface/level/overlay=total_precipitable_water/orthographic=-123.35,23.53,1318/loc=-120.336,39.403

    Also interesting how everyone in the climate modelling business predicted this to be a dry year along the West Coast!
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  110. Anonym says:
    @anon
    I'm told, by a reliable source, that in some of the toilets in the Medical Faculty Building at the University of Queensland, above the paper dispenser, were written these words:
    Engineering Degrees- please take one.

    Tell that to Xi Jinping.

    If you artificially restricted entrance to engineering schools like they do medicine, then engineers would be paid more. Still they are paid well.

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  111. Bruce says:
    @Anonymous Nephew
    "If I was dropping boulders from a helicopter into the hole, I’d use wire rope to hold them together. Let the energy of the water go into bouncing the boulders up and down and tangling themselves together, not into bouncing the boulders out of the hole."

    That is a very good idea. Same sort of thing that makes the Hesco Bastion better protection than a pile of rocks and sand. Seeing that the holes are random-size and shape, how about a steel-cable mesh bag filled with rocks, that could be dropped in a hole and would then conform to the hole shape and not leave too many big voids? A flexible gabion. But you'd need a lot of steel for such a bag, so maybe drilling holes and threading the rocks on would be better? Hmm. Bag's more elegant if you can make one. Make the bag from Kevlar or similar tough fibre, then link the bags together in situ? Wouldn't rust like steel.

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

    I’d never heard of Hesco Bastions. They look like a good thing to stuff into that hole. Maybe with wire rope loosely attaching them to bedrock, if you can find bedrock.

    And I’d put wire rope by itself in the hole, one end bolted to bedrock, one end loose. Let the random blasts of water pressure meet a wild hair of randomly whipping wire.

    If I had a really big air compressor just sitting there, it would be nice to blow the falling water away from the spillway. Make as much as possible fall into the river or at least land like hard rain, not like the raping trident marlinspike of Poseidon Ultor.

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    • Replies: @Anonymous Nephew
    The owner of Hesco Bastions, an ex-miner, made a fortune from the various Iraq wars, where they were perfect for blast protection. He died when his Segway fell off a cliff.

    https://en.wikipedia.org/wiki/Hesco_bastion
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  112. Anonym says:
    @newrouter
    "The metric system is better."


    Mathematically better. But overall, like saying Esperanto is better than English.

    No, the metric system is definitely better for anyone who does anything involving physics or engineering as a living. It is designed to make sense and be easy to use from the beginning, instead of being an amalgamation of different medieval units and measures. That’s why everyone but the USA and two other countries have adopted the metric system. The others are Liberia and Burma – real world leaders there. And Burma is taking steps to adopt it officially. So basically there is the US… and Liberia.

    That even with all the USA’s might and soft power, they can’t convince the rest of the world to embrace its stupid system. And attend a US college – you will find that in technical subjects metric is used. Even the USA uses metric in many applications.

    So, if everyone in the world spoke Esperanto, yes, Metric would be like it.

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    • Replies: @Hodag
    You will take my hogsheads when you pry it from my cold, dead fingers.

    Everyone knows that there are 4306.79486516 hogshead(UK) to the acre foot. Which everyone knows that one hogshead (UK) is 26.2292369267 peck(UK). And everyone knows these measures are different in the US. How many US pecks per second are going down the spillway? Many is my calculation.
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  113. @Bruce
    I'd never heard of Hesco Bastions. They look like a good thing to stuff into that hole. Maybe with wire rope loosely attaching them to bedrock, if you can find bedrock.

    And I'd put wire rope by itself in the hole, one end bolted to bedrock, one end loose. Let the random blasts of water pressure meet a wild hair of randomly whipping wire.

    If I had a really big air compressor just sitting there, it would be nice to blow the falling water away from the spillway. Make as much as possible fall into the river or at least land like hard rain, not like the raping trident marlinspike of Poseidon Ultor.

    The owner of Hesco Bastions, an ex-miner, made a fortune from the various Iraq wars, where they were perfect for blast protection. He died when his Segway fell off a cliff.

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

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    • Replies: @The Anti-Gnostic
    Why would such a smart man use a Segway in that fashion? Tragic.
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  114. All that engineering talk is fine and good, but the Oroville Dam is nothing more than further evidence that we urgently need to do more to reverse catastrophic man-caused climate change that has first given California a severe drought that will never end and then cruelly ended that drought with dam-busting rains.

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  115. @Clyde
    Solid interview with a man in the dam building business for 40 years
    https://peakprosperity.com/podcast/107126/expert-what-need-know-about-oroville-dam-crisis


    Scott Cahill: Exactly. What they had said is only probably a day ago was that this wasn’t a significant problem because if we simply close the gates, the valves on the top end of the principle spillway, then the water will rise and spill over the emergency spillway and the emergency spillway has a magnificent capacity to move water. Well, when they allowed just a bit of water to run over the emergency spillway they soon found with the velocities of only a portion of the water that could be moving over that emergency spillway. They had such severe scour that they anticipated a failure of the structural elements within 45 minutes.

    That initiated them moving people out of the inundation zone beneath the dam. And now I believe the thought is that the cut back on the principle spillway is slower than the failure mode on the emergency spillway, so they’re going to vent water down that principle spillway as much as they can without failing that element.

    excerpt

    Thanks for that link; it’s a really good interview with lots of specialist information.

    An ominous quotation from Cahill here:

    There are many dams which are in horrible, horrible shape, unbelievable shape across the United States. Many states have 4,000 dams. Many states have 2,000 and 3,000 dams. Of those dams I would imagine that 20% are in an absolutely untenable situation.

    When we look at this dam, which is a highly regulated dam, a dam more highly regulated than almost any others. They had an emergency spillway filled with trees. They had a principle spillway that was in the process of failing and had been for years. So, if this can exist on one of the most highly regulated dams then one can just interpolate and imagine what the rest of the situation is like.

    Dams and infrastructure in general in these United States have been ignored since they were constructed; many of them 100 years old. The mass of them more than 50 years old. And the design life when they were constructed, generally 50 years. We – it’s hard politically to go back and spend the money proactively to develop safety because nothing has happened. And so, with dam safety, time and time again we act after the horrible event. Something really horrible happens and someone reacts to that and says, “You know I will never let this happen again”. And indeed we move forward. And then the pressure is off and it’s not frightening anymore and we go back to a level of complacency that allows us to get where we stand today.

    Dams are in terrible shape in the United States as are all of our infrastructure, bridges, 600,000 bridges with 27% of them not meeting their minimum requirements. A number of these high hazard dams are not even close. There’s a report card given out by the American Society of Civil Engineers and many states, dam inventories are getting D’s, D minuses, D plusses. It’s hard to believe. Certainly someone in the 1960’s would never believe that the United States would have these issues, but we’ve ignored them far too long . . . .

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    • Replies: @Clyde
    Going by what Cahill said both spillways are compromised. They will use one or the other very gingerly and monitor for collapse and destruction of either spillway. As they try to keep dam levels low enough to get through this rainy season and when the snow packs melt throwing even more water into Lake Oroville. After these two seasons they will work like demons to repair both and clear debris so the generators and their water outlets can be used again.

    There are expansion joints between the concrete slabs poured for the primary spillways. This was where the big hole started plus some slabs heave suffered erosion underneath for rainfall since the dam was built making for more instability. There is water running beneath those slabs right now as the water pours down out of the damn.

    Just for real stupidity... underneath the secondary (emergency) spillway trees and shrubs were allowed to grow. According to Cahill very negligent, because as water escapes down that spillway it pulls out trees by the rootballs, leaving a large pit left that accelerates erosion.

    , @Krollchem
    Thanks for the dam and bridge rundown, rundown. Same issue applies to roads and sewers. Infrastructure doesn't seem to be a sexy issue in the political campaigns?

    It will take a lot of energy to fix these problems. From what I have read the Energy Return on Energy Invested (EROEI) is dropping as conventional oil resources are drying up and being replaced by fracking.

    Infrastructure projects would also create many more jobs than sexy weapons systems and NSA server farms.
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  116. @George Taylor
    In 1983 the Glenn Canyon Dam (Lake Powell) almost collapsed in a very similar scenario. Can you imagine? Lake Powell is immense compared to Oroville.

    A record 120,000 cfs was flowing into Lake Powell from late spring snow and rain in the Rocky Mountains that no one had anticipated. On July 2, the lake - considered full at 3700' - was just 3.5 feet from its maximum capacity of 3711' and rising three inches a day.

    The July 8 issue reported that the dam's spillway began breaking up when officials upped the release to 92,000 cfs. The high velocity water was carving out huge holes in one of the tunnels, a process known as cavitation that sent chunks of concrete and red silt from the eroding Navajo sandstone bedrock shooting into the clear river below the dam.

    Officials at Glen Canyon dam quoted in the story admitted the spillways contained "known design flaws." Averting a massive disaster became their priority. Meanwhile, the second spillway tunnel was beginning to suffer damage.
     
    http://www.hcn.org/40years/blog/the-summer-the-dam-almost-didnt

    I know some people who were there. In an effort to stop the dam from being overtopped (OM&#@$G), they used *plywood* to add a few extra feet to the dam height. Seemed to have worked.

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  117. fitzGetty says:

    So: the Sanctuary State has not got the will to manage the water supply to its Sanctuary Cities safely … how very 3rd world …

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    • Replies: @Buck Turgidson
    Classic example of how liberals get themselves all confused with way too many incompatible dreams and goals. They hate dams, but love open borders. Of course this shoots urban water demand to the moon (in a desert). I don't know why it is so hard for them to think through these seemingly simple concepts and linkages. Maybe their ideology just overpowers their cranial circuitry.

    California's biggest water problem is not climate/drought/flood, but too many people and massive increases in urban water demand overloading the system, and impinging on water demand in other sectors (irrigated ag, and environment and endgrd species). The skyrocketing immigration (they love) takes water from and damages river ecology (they don't like that). DUH.

    The best thing that could happen for California's water systems would be for all the illegals to go home (where they belong) and the nation (US) enact a moratorium on immigration.

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  118. @David Davenport
    So, to reiterate, in the metric system clear thinking becomes much easier. And no, as potential commenters will no doubt argue, this is not an issue for ME PERSONALLY because I scored in the 99th percentile in math and general reasoning–which is the very reason I can see the confusion in the minds of those around me and is what enables me to recognize that it is a substantial issue for many of my struggling contemporaries.

    Three Brains:

    Are you also a MENSA member with a proven IQ of 500 who has been an authentic jazzman for the last 80 years?

    Here's some questions:

    Suppose there are two man-made reservoirs, both full of water. Both are round, both have flat bottoms with a depth of 100 meters. One reservoir is 100 meters in diameter. The other reservoir is one kilometer in diameter. Suppose a hole one meter in diameter is opened at the bottom of both of the two reservoirs, from which water is free to drain into the ambient air. Assume the surfaces of both reservoirs are 100 meters above sea level.

    (1) What will the water pressure be at the hole at the bottom of the 100 meter diameter reservoir?

    (2) What will the water pressure be at the hole at the bottom of the 1 kilometer diameter reservoir?

    1. 160 pounds per square inch
    2. 2998 inches of mercury

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    • Replies: @David Davenport
    Hippodrome:

    Thankee for not answering in Muggles measures, a.k.a. metric, the unit system of globalists and would-be speakers of Esperanto.

    I must also ask, have you been an authentic jazz man and MENSA member?

    The US Dept. of Def. uses both English and metric measures, plus knots and nautical miles. OK, knots may count as English units.
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  119. Hodag says:
    @Steve Sailer
    Thanks.

    The main spillway explosion dumped a lot of debris into the river, which partially dammed the river, raising the water level, blocking the power plant from operating.

    And the erosion around the main spillway threatened to undermine the power towers so they took down the power cables via helicopter.

    So they have to fix both problems by dredging the river and by moving the power towers higher up and restringing the wires to get the power station working again.

    That's a lot of work.

    Couldn’t they just run a set of wires 3000 feet in the opposite direction, drive an iron rod to bedrock and ground it?

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  120. Hodag says:
    @Anonym
    No, the metric system is definitely better for anyone who does anything involving physics or engineering as a living. It is designed to make sense and be easy to use from the beginning, instead of being an amalgamation of different medieval units and measures. That's why everyone but the USA and two other countries have adopted the metric system. The others are Liberia and Burma - real world leaders there. And Burma is taking steps to adopt it officially. So basically there is the US... and Liberia.

    That even with all the USA's might and soft power, they can't convince the rest of the world to embrace its stupid system. And attend a US college - you will find that in technical subjects metric is used. Even the USA uses metric in many applications.

    So, if everyone in the world spoke Esperanto, yes, Metric would be like it.

    You will take my hogsheads when you pry it from my cold, dead fingers.

    Everyone knows that there are 4306.79486516 hogshead(UK) to the acre foot. Which everyone knows that one hogshead (UK) is 26.2292369267 peck(UK). And everyone knows these measures are different in the US. How many US pecks per second are going down the spillway? Many is my calculation.

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    • Replies: @Anonym
    Many is my calculation.

    Primitives can count 1, 2 or many. Such is it with the imperial system, that vast empire consisting of the USA and Liberia.

    Yes I realize you are being facetious.
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  121. Austrian says:
    @David Davenport
    So, to reiterate, in the metric system clear thinking becomes much easier. And no, as potential commenters will no doubt argue, this is not an issue for ME PERSONALLY because I scored in the 99th percentile in math and general reasoning–which is the very reason I can see the confusion in the minds of those around me and is what enables me to recognize that it is a substantial issue for many of my struggling contemporaries.

    Three Brains:

    Are you also a MENSA member with a proven IQ of 500 who has been an authentic jazzman for the last 80 years?

    Here's some questions:

    Suppose there are two man-made reservoirs, both full of water. Both are round, both have flat bottoms with a depth of 100 meters. One reservoir is 100 meters in diameter. The other reservoir is one kilometer in diameter. Suppose a hole one meter in diameter is opened at the bottom of both of the two reservoirs, from which water is free to drain into the ambient air. Assume the surfaces of both reservoirs are 100 meters above sea level.

    (1) What will the water pressure be at the hole at the bottom of the 100 meter diameter reservoir?

    (2) What will the water pressure be at the hole at the bottom of the 1 kilometer diameter reservoir?

    Suppose there are two man-made reservoirs, both full of water. Both are round, both have flat bottoms with a depth of 100 meters. One reservoir is 100 meters in diameter. The other reservoir is one kilometer in diameter. Suppose a hole one meter in diameter is opened at the bottom of both of the two reservoirs, from which water is free to drain into the ambient air. Assume the surfaces of both reservoirs are 100 meters above sea level.

    (1) What will the water pressure be at the hole at the bottom of the 100 meter diameter reservoir?

    (2) What will the water pressure be at the hole at the bottom of the 1 kilometer diameter reservoir?

    ~10 bar in both cases. This is not a good IQ test. Any plumber would know the answer. Many Geniuses who are illiterate in physics on the other hand would not.


    They should build a giant immersion heater. Throw some pipe into the reservoir. Connect it to the power station. A galvanic anode would be needed to prevent corrosion. Aluminum would do the trick.

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    • Replies: @Anonym
    I am not sure it would be 10 bar at the hole itself. On the bottom of the reservoir, 10m in any direction, about 10 bar. Certainly if there were no hole, also 10 bar. But with a hole suddenly water would be pouring out at a great velocity that should initially be identical in both cases (though the smaller reservoir will drain more rapidly, so the pressure and velocity drop is much faster over time). 10m below the pipe, while one wouldn't want to be standing under it when the hole is opened, if one were in the stream itself moving along with it, it should be at atmospheric pressure or close to it. Consider that water can be considered to be incompressible, so if it's above atmospheric it can instantly expand to not be at 10 bar any more, and this is done with minimal movement. Thus it should be at atmospheric at that point. Using the same logic, it is possible that the pressure is also at atmospheric in the water stream only 1m below the hole.

    The Bernouli principle states that an increase in the speed of a fluid occurs simultaneously with a decrease in pressure or a decrease in the fluid's potential energy. (That is the only thing I have googled btw, I didn't want to embarrass myself by getting it wrong.) (The beauty of schooling is at least you remember what you need to look up, or how to find the info.) So you can see that 10m inside, the rough hemisphere of equal velocity is moving very slowly compared to the 1m hole at the bottom. The pressure should be roughly at 10 bar. But as we get closer to the hole, the velocity increases, and the pressure should be dropping. At the hole itself, parallel with the bottom of the reservoir, the velocity should be at a maximum due pressure other than the increase due to acceleration due to gravity below the hole. So that may well be at atmospheric too, but immediately inside the pressure starts to increase.

    My gut feeling in this case is to not be 100% sure of my reasoning but to try and replicate the experiment with a pressure gauge and make sure I am not embarrassing myself, but I think this is something of a trick question and I am on the right track, if not correct I am close to it. The devil is in the details with these things and it's best not to be too sure except in the approximately static case. Someone who does fluid dynamics as their bread and butter would be a lot more sure than I am.

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  122. @Anonymous Nephew
    The owner of Hesco Bastions, an ex-miner, made a fortune from the various Iraq wars, where they were perfect for blast protection. He died when his Segway fell off a cliff.

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

    Why would such a smart man use a Segway in that fashion? Tragic.

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    • Replies: @Anonymous Nephew
    He'd bought the Segway company, obviously loved them but got a tad careless.
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  123. eah says:
    @eah
    if the main spillway holds up to the pounding its (sic) taking

    What "pounding"? -- looks like normal use to me -- a Challenger-like special inquiry is in order to look into the design, construction, and inspection/maintenance of the main spillway -- its dramatic failure is a scandal.

    Also the 'emergency spillway' -- aka a hillside -- is a joke.

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  124. @David Davenport
    So, to reiterate, in the metric system clear thinking becomes much easier. And no, as potential commenters will no doubt argue, this is not an issue for ME PERSONALLY because I scored in the 99th percentile in math and general reasoning–which is the very reason I can see the confusion in the minds of those around me and is what enables me to recognize that it is a substantial issue for many of my struggling contemporaries.

    Three Brains:

    Are you also a MENSA member with a proven IQ of 500 who has been an authentic jazzman for the last 80 years?

    Here's some questions:

    Suppose there are two man-made reservoirs, both full of water. Both are round, both have flat bottoms with a depth of 100 meters. One reservoir is 100 meters in diameter. The other reservoir is one kilometer in diameter. Suppose a hole one meter in diameter is opened at the bottom of both of the two reservoirs, from which water is free to drain into the ambient air. Assume the surfaces of both reservoirs are 100 meters above sea level.

    (1) What will the water pressure be at the hole at the bottom of the 100 meter diameter reservoir?

    (2) What will the water pressure be at the hole at the bottom of the 1 kilometer diameter reservoir?

    The same.

    Read More
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  125. @The Anti-Gnostic
    Why would such a smart man use a Segway in that fashion? Tragic.

    He’d bought the Segway company, obviously loved them but got a tad careless.

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  126. They’re reducing flow to 95k cft/s “w/more reductions to follow to allow removal of debris from diversion pool” – I assume so they can use the power channel, though whe

    Elsewhere what appears to be a diagram of the dam, source uncertain but it looks like the power tunnel outfall isn’t terribly close to the spillway.

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    • Replies: @res

    Elsewhere what appears to be a diagram of the dam, source uncertain but it looks like the power tunnel outfall isn’t terribly close to the spillway.
     
    That's true, but if you look at the (50 foot interval?) contour lines there doesn't appear to be much slope in the river between those two points--making Steve's water backing up over the turbine outlets because of spillway debris theory plausible. I wonder what design goals/requirements for turbine outlet clearance are? If there are any before/after pictures of the turbine outlets available those would be more conclusive.

    Here is an interactive topo map of the area: https://www.topoquest.com/map.php?lat=39.53803&lon=-121.50088&datum=nad27&zoom=4&map=auto&coord=d&mode=zoomin&size=m
    If I read the map correctly it shows the route of the powerlines. Running them across the emergency spillway slope seems like a really bad choice.

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  127. Anonym says:
    @Austrian

    Suppose there are two man-made reservoirs, both full of water. Both are round, both have flat bottoms with a depth of 100 meters. One reservoir is 100 meters in diameter. The other reservoir is one kilometer in diameter. Suppose a hole one meter in diameter is opened at the bottom of both of the two reservoirs, from which water is free to drain into the ambient air. Assume the surfaces of both reservoirs are 100 meters above sea level.

    (1) What will the water pressure be at the hole at the bottom of the 100 meter diameter reservoir?

    (2) What will the water pressure be at the hole at the bottom of the 1 kilometer diameter reservoir?
     

    ~10 bar in both cases. This is not a good IQ test. Any plumber would know the answer. Many Geniuses who are illiterate in physics on the other hand would not.

    @Steve Sailer
    They should build a giant immersion heater. Throw some pipe into the reservoir. Connect it to the power station. A galvanic anode would be needed to prevent corrosion. Aluminum would do the trick.

    I am not sure it would be 10 bar at the hole itself. On the bottom of the reservoir, 10m in any direction, about 10 bar. Certainly if there were no hole, also 10 bar. But with a hole suddenly water would be pouring out at a great velocity that should initially be identical in both cases (though the smaller reservoir will drain more rapidly, so the pressure and velocity drop is much faster over time). 10m below the pipe, while one wouldn’t want to be standing under it when the hole is opened, if one were in the stream itself moving along with it, it should be at atmospheric pressure or close to it. Consider that water can be considered to be incompressible, so if it’s above atmospheric it can instantly expand to not be at 10 bar any more, and this is done with minimal movement. Thus it should be at atmospheric at that point. Using the same logic, it is possible that the pressure is also at atmospheric in the water stream only 1m below the hole.

    The Bernouli principle states that an increase in the speed of a fluid occurs simultaneously with a decrease in pressure or a decrease in the fluid’s potential energy. (That is the only thing I have googled btw, I didn’t want to embarrass myself by getting it wrong.) (The beauty of schooling is at least you remember what you need to look up, or how to find the info.) So you can see that 10m inside, the rough hemisphere of equal velocity is moving very slowly compared to the 1m hole at the bottom. The pressure should be roughly at 10 bar. But as we get closer to the hole, the velocity increases, and the pressure should be dropping. At the hole itself, parallel with the bottom of the reservoir, the velocity should be at a maximum due pressure other than the increase due to acceleration due to gravity below the hole. So that may well be at atmospheric too, but immediately inside the pressure starts to increase.

    My gut feeling in this case is to not be 100% sure of my reasoning but to try and replicate the experiment with a pressure gauge and make sure I am not embarrassing myself, but I think this is something of a trick question and I am on the right track, if not correct I am close to it. The devil is in the details with these things and it’s best not to be too sure except in the approximately static case. Someone who does fluid dynamics as their bread and butter would be a lot more sure than I am.

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    • Replies: @Austrian
    Total pressure = dynamic pressure + static pressure. It still adds up to 10.

    I just now realized that David Davenport was reacting to ThreeCranes' considerations of inflow, outflow, pressure, etc. ThreeCranes seems to claim that outflow will eventually match inflow, because of the pressure increase it provides.

    But this is not true. The outflow velocity depends entirely on the water depth. The volume does not matter.
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  128. Anonym says:
    @anon
    I'm told, by a reliable source, that in some of the toilets in the Medical Faculty Building at the University of Queensland, above the paper dispenser, were written these words:
    Engineering Degrees- please take one.

    Where is the doctor equivalent of Carlos Slim? When it comes to earning potential at the high end for engineers and their companies, the dick waving competition comes out in favor of the engineer. That’s a nice Maserati doctor, would you like to take a ride in my gulfstream?

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  129. Anonym says:
    @Steve Sailer
    I don't have good 3-d thinking skills. I can't think in 2-d terms pretty well, but there's a huge dropoff in performance when I have to switch from Flatland to Spaceland.

    Arithmetic will get you pretty far in a lot of businesses, especially the ability to multiply and divide approximately in your head while sitting around a conference table during a meeting.

    I think you undersell yourself, as you are dealing with volumes here, which are inherently 3d. Although it’s a fairly easy 3d shape, you still remark that the reservoir is shaped like a funnel and that has ramifications re: volume vs vs water depth below maximum being non-linear. You also grasp the area of catchment, the rainfall flux, the idea that something less than 100% of the rainfall must enter the reservoir. And that conservation of mass should apply, ignoring evaporation. So water mass = initial water mass plus outflow less inflow.

    With no background, I think you’ve already entered high school extra credit physics type work. It’s funny that in college engineering work, there is that moment to put on the big boy pants. What once was extra credit and worth a pat on the back becomes the expected – either do it, and do it right, or fail. Someone who is capable of understanding the physical world and getting it right, i.e. an engineer or someone who could succeed as an engineer, will be able to look at a novel situation such as this and get it right most of the time.

    We need more people who are capable of this sort of thought running the country, engaging in the debates, and shaping the debates. Proposed systems need to work. This is something China gets right, with the numbers of engineers in government. Though broader experience than engineering is also needed.

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  130. Clyde says:
    @The Last Real Calvinist
    Thanks for that link; it's a really good interview with lots of specialist information.

    An ominous quotation from Cahill here:

    There are many dams which are in horrible, horrible shape, unbelievable shape across the United States. Many states have 4,000 dams. Many states have 2,000 and 3,000 dams. Of those dams I would imagine that 20% are in an absolutely untenable situation.

    When we look at this dam, which is a highly regulated dam, a dam more highly regulated than almost any others. They had an emergency spillway filled with trees. They had a principle spillway that was in the process of failing and had been for years. So, if this can exist on one of the most highly regulated dams then one can just interpolate and imagine what the rest of the situation is like.

    Dams and infrastructure in general in these United States have been ignored since they were constructed; many of them 100 years old. The mass of them more than 50 years old. And the design life when they were constructed, generally 50 years. We – it’s hard politically to go back and spend the money proactively to develop safety because nothing has happened. And so, with dam safety, time and time again we act after the horrible event. Something really horrible happens and someone reacts to that and says, “You know I will never let this happen again”. And indeed we move forward. And then the pressure is off and it’s not frightening anymore and we go back to a level of complacency that allows us to get where we stand today.

    Dams are in terrible shape in the United States as are all of our infrastructure, bridges, 600,000 bridges with 27% of them not meeting their minimum requirements. A number of these high hazard dams are not even close. There’s a report card given out by the American Society of Civil Engineers and many states, dam inventories are getting D’s, D minuses, D plusses. It’s hard to believe. Certainly someone in the 1960’s would never believe that the United States would have these issues, but we’ve ignored them far too long . . . .
     

    Going by what Cahill said both spillways are compromised. They will use one or the other very gingerly and monitor for collapse and destruction of either spillway. As they try to keep dam levels low enough to get through this rainy season and when the snow packs melt throwing even more water into Lake Oroville. After these two seasons they will work like demons to repair both and clear debris so the generators and their water outlets can be used again.

    There are expansion joints between the concrete slabs poured for the primary spillways. This was where the big hole started plus some slabs heave suffered erosion underneath for rainfall since the dam was built making for more instability. There is water running beneath those slabs right now as the water pours down out of the damn.

    Just for real stupidity… underneath the secondary (emergency) spillway trees and shrubs were allowed to grow. According to Cahill very negligent, because as water escapes down that spillway it pulls out trees by the rootballs, leaving a large pit left that accelerates erosion.

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  131. res says:
    @Anonymous Nephew
    They're reducing flow to 95k cft/s "w/more reductions to follow to allow removal of debris from diversion pool" - I assume so they can use the power channel, though whe

    https://twitter.com/CA_DWR/status/832297248423763968

    Elsewhere what appears to be a diagram of the dam, source uncertain but it looks like the power tunnel outfall isn't terribly close to the spillway.

    https://pbs.twimg.com/media/C4zkClZWQAEES8Q.jpg

    Elsewhere what appears to be a diagram of the dam, source uncertain but it looks like the power tunnel outfall isn’t terribly close to the spillway.

    That’s true, but if you look at the (50 foot interval?) contour lines there doesn’t appear to be much slope in the river between those two points–making Steve’s water backing up over the turbine outlets because of spillway debris theory plausible. I wonder what design goals/requirements for turbine outlet clearance are? If there are any before/after pictures of the turbine outlets available those would be more conclusive.

    Here is an interactive topo map of the area: https://www.topoquest.com/map.php?lat=39.53803&lon=-121.50088&datum=nad27&zoom=4&map=auto&coord=d&mode=zoomin&size=m
    If I read the map correctly it shows the route of the powerlines. Running them across the emergency spillway slope seems like a really bad choice.

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    • Replies: @Steve Sailer
    The debris from the spillway formed a mini-dam in the river, raising the water level of the Feather River at the power station to high to spin the turbines. Currently, they are dredging the river and they are easing off on the water down the main spillway to 80k cfs in hopes of getting the power house outlet (13k cfs) started again.
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  132. Anonym says:

    Btw here is some analysis not in the thread.

    Volume = 4.3km^3
    Mass = 4.3 billion tonnes water = 4.3 trillion kg
    Height = 235m
    Avg Height = 118m

    Potential energy = mgh = 4.3 tril x 9.8 x 118 = 5 E 15 Joules

    1 tonne tnt = 4.2 E 9 Joules

    Therefore energy in dam is 1.2Mt of TNT.

    Strategic nuke incoming!

    (Hiroshima was 15kt. Tsar Bomba was 57Mt.)

    Please check my math. I originally forgot to convert tonnes to kg, so I had 1.5kt originally.

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    • Replies: @Steve Sailer
    The details of how the emergency spillway might fail are important, such as a leak versus a collapse. I have a vague hunch that if the spillway is going to go they's blow a hole in the parking lot next to the emergency spillway at the end of the way from the top 30 feet of the dam to drain the lake into the Feather River at a point maybe two miles below the dam. What you really don't want is the top 30 feet, or 450,000 acre feet falling all once 600+ feet down into river only a mile below the dam. That would probably generate a mini-tsunami that boils back up and hits the un-armored downstream front of the dam, which could be very bad.
    , @Anonym
    In looking at the Banquio dam and doing similar math on that one (coming up with a significantly smaller result), I thought to recheck things here. It turns out my source for the volume is wrong. :/ Oroville actually holds 59MT.

    Plugging the numbers back in, I get:

    GPE = 59E9 kg * 9.8 * 118 = 6.8 E13 Joules

    tonnes of TNT equivalent = 6.8E13/4.2E9 = 16kt TNT.

    So it's very similar in energy to the Hiroshima Little Boy bomb. It's what's referred to these days as a tactical nuke. So that's less alarming. I'm sure the people of Hiroshima were happy to know they got hit by a relatively small yield device.

    I've worked out a formula to quickly calculate an estimate of Gravitational Potential Energy for a dam's reservoir in terms of kt of tnt.

    E(kt) = 1.17 V * h
    Where V is dam volume in km^3 and h is total dam height in m. Note that you can easily convert via google, e.g. type "convert 59000000km^3 to m^3" and it will spit out the answer.

    Due to the funnel shape of reservoirs (not too many overhangs in natural features), this will underestimate things as most of the volume is going to be in the upper half of the height range. It may underestimate the GPE by nearly half the true value. But like astrophysics and nuclear physics, getting the order of magnitude of the result is the most important thing.

    The largest reservoir of a dam in the world (ignoring natural lake augmentation) is the Kariba dam. That holds 185km^3 volume and is 128m tall. Plugging that into my formula, the yield is 27,705kt of TNT. 27Mt. So that's about half a Tsar Bomba. A dam failure flood has the "beauty" of not wasting all that energy into the upper atmosphere like Tsar Bomba. The flood spreads out efficiently wiping out everything in its path. That's the reason ICBMs have been designed to get more efficient devastation with a dispersed cluster of lower yield devices. Tsar Bomba was impractical as a weapon - just a combination of nuclear engineers indulging their inner 14yo boy and Cold War dick waving exercise that Stalin went along with.

    Thus, now that (I think?) I have correctly come up with a formula to estimate dam potential energy in terms of kt of tnt, it is no surprise to me that wikipedia states about this dam: "Along with the devastation of wildlife in the valley, the Zambezi River Authority estimates that the lives of 3.5 million people are at risk." Even 3.5m people isn't going to put a dent in the African population explosion. A Detroit in every neighborhood, the dream of Bono.

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

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  133. Anonym says:
    @Hodag
    You will take my hogsheads when you pry it from my cold, dead fingers.

    Everyone knows that there are 4306.79486516 hogshead(UK) to the acre foot. Which everyone knows that one hogshead (UK) is 26.2292369267 peck(UK). And everyone knows these measures are different in the US. How many US pecks per second are going down the spillway? Many is my calculation.

    Many is my calculation.

    Primitives can count 1, 2 or many. Such is it with the imperial system, that vast empire consisting of the USA and Liberia.

    Yes I realize you are being facetious.

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    • Replies: @Anonym
    Actually now I think about it, Liberia is non-Metric, but probably not Imperial. I tried to find out before, but it looked to take too much work.

    So the Imperial system holds sway in the vast empire consisting of the USA, at least, only in the non-technical parts of the USA, and thus it has been for a long time. Consider the A10, first flown in 1972 - built around a 30mm rotary cannon. Or consider the 5.56mm NATO round. When it has to work, people who work with numbers for a living use metric.
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  134. Krollchem says:
    @Steve Sailer
    Thanks.

    The main spillway explosion dumped a lot of debris into the river, which partially dammed the river, raising the water level, blocking the power plant from operating.

    And the erosion around the main spillway threatened to undermine the power towers so they took down the power cables via helicopter.

    So they have to fix both problems by dredging the river and by moving the power towers higher up and restringing the wires to get the power station working again.

    That's a lot of work.

    Perhaps more good luck for the engineers who are trying to fix this political mess is on the way. It appears that the atmospheric river is being pushed further South toward LA:

    https://earth.nullschool.net/#current/wind/surface/level/overlay=total_precipitable_water/orthographic=-123.35,23.53,1318/loc=-120.336,39.403

    Also interesting how everyone in the climate modelling business predicted this to be a dry year along the West Coast!

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    • Replies: @Steve Sailer
    Yup, we could use some more rain in SoCal, although a couple of reservoirs are near full, but hopefully they could pump water from Castaic and Pyramid Lakes to half empty Lake Perris. We've had a nice amount of rain so far, but we could use more to make up for the last few years of drought.

    Everybody was predicting that last winter was going to be a very wet El Nino year. Instead, it was pretty dry and then late in the season Lakes Oroville and Shasta got filled up most of the way by stormm that just barely got far enough south to save the state from another year of hyper drought. I don't recall anybody predicting this would be a rainy winter.

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  135. Krollchem says:
    @The Last Real Calvinist
    Thanks for that link; it's a really good interview with lots of specialist information.

    An ominous quotation from Cahill here:

    There are many dams which are in horrible, horrible shape, unbelievable shape across the United States. Many states have 4,000 dams. Many states have 2,000 and 3,000 dams. Of those dams I would imagine that 20% are in an absolutely untenable situation.

    When we look at this dam, which is a highly regulated dam, a dam more highly regulated than almost any others. They had an emergency spillway filled with trees. They had a principle spillway that was in the process of failing and had been for years. So, if this can exist on one of the most highly regulated dams then one can just interpolate and imagine what the rest of the situation is like.

    Dams and infrastructure in general in these United States have been ignored since they were constructed; many of them 100 years old. The mass of them more than 50 years old. And the design life when they were constructed, generally 50 years. We – it’s hard politically to go back and spend the money proactively to develop safety because nothing has happened. And so, with dam safety, time and time again we act after the horrible event. Something really horrible happens and someone reacts to that and says, “You know I will never let this happen again”. And indeed we move forward. And then the pressure is off and it’s not frightening anymore and we go back to a level of complacency that allows us to get where we stand today.

    Dams are in terrible shape in the United States as are all of our infrastructure, bridges, 600,000 bridges with 27% of them not meeting their minimum requirements. A number of these high hazard dams are not even close. There’s a report card given out by the American Society of Civil Engineers and many states, dam inventories are getting D’s, D minuses, D plusses. It’s hard to believe. Certainly someone in the 1960’s would never believe that the United States would have these issues, but we’ve ignored them far too long . . . .
     

    Thanks for the dam and bridge rundown, rundown. Same issue applies to roads and sewers. Infrastructure doesn’t seem to be a sexy issue in the political campaigns?

    It will take a lot of energy to fix these problems. From what I have read the Energy Return on Energy Invested (EROEI) is dropping as conventional oil resources are drying up and being replaced by fracking.

    Infrastructure projects would also create many more jobs than sexy weapons systems and NSA server farms.

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  136. @fitzGetty
    So: the Sanctuary State has not got the will to manage the water supply to its Sanctuary Cities safely ... how very 3rd world ...

    Classic example of how liberals get themselves all confused with way too many incompatible dreams and goals. They hate dams, but love open borders. Of course this shoots urban water demand to the moon (in a desert). I don’t know why it is so hard for them to think through these seemingly simple concepts and linkages. Maybe their ideology just overpowers their cranial circuitry.

    California’s biggest water problem is not climate/drought/flood, but too many people and massive increases in urban water demand overloading the system, and impinging on water demand in other sectors (irrigated ag, and environment and endgrd species). The skyrocketing immigration (they love) takes water from and damages river ecology (they don’t like that). DUH.

    The best thing that could happen for California’s water systems would be for all the illegals to go home (where they belong) and the nation (US) enact a moratorium on immigration.

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  137. @Krollchem
    Perhaps more good luck for the engineers who are trying to fix this political mess is on the way. It appears that the atmospheric river is being pushed further South toward LA:

    https://earth.nullschool.net/#current/wind/surface/level/overlay=total_precipitable_water/orthographic=-123.35,23.53,1318/loc=-120.336,39.403

    Also interesting how everyone in the climate modelling business predicted this to be a dry year along the West Coast!

    Yup, we could use some more rain in SoCal, although a couple of reservoirs are near full, but hopefully they could pump water from Castaic and Pyramid Lakes to half empty Lake Perris. We’ve had a nice amount of rain so far, but we could use more to make up for the last few years of drought.

    Everybody was predicting that last winter was going to be a very wet El Nino year. Instead, it was pretty dry and then late in the season Lakes Oroville and Shasta got filled up most of the way by stormm that just barely got far enough south to save the state from another year of hyper drought. I don’t recall anybody predicting this would be a rainy winter.

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  138. @Anonym
    Btw here is some analysis not in the thread.

    Volume = 4.3km^3
    Mass = 4.3 billion tonnes water = 4.3 trillion kg
    Height = 235m
    Avg Height = 118m

    Potential energy = mgh = 4.3 tril x 9.8 x 118 = 5 E 15 Joules

    1 tonne tnt = 4.2 E 9 Joules

    Therefore energy in dam is 1.2Mt of TNT.

    Strategic nuke incoming!

    (Hiroshima was 15kt. Tsar Bomba was 57Mt.)

    Please check my math. I originally forgot to convert tonnes to kg, so I had 1.5kt originally.

    The details of how the emergency spillway might fail are important, such as a leak versus a collapse. I have a vague hunch that if the spillway is going to go they’s blow a hole in the parking lot next to the emergency spillway at the end of the way from the top 30 feet of the dam to drain the lake into the Feather River at a point maybe two miles below the dam. What you really don’t want is the top 30 feet, or 450,000 acre feet falling all once 600+ feet down into river only a mile below the dam. That would probably generate a mini-tsunami that boils back up and hits the un-armored downstream front of the dam, which could be very bad.

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    • Replies: @Anonym
    Yes. I am not sure how far below and what quality bedrock is situated around the edges of the dam, but it seems to me that an ideal emergency way to diffuse the situation is to find an area where there is good bedrock a few feet but not too far below the maximum height of the dam, that leads to a relatively uninhabitated valley along its extent. Then blow a channel wide enough that it can flow enough to exhaust the flow of water that the maximum rainfall is likely to deliver. It would be best if this were not anywhere near the business end of the dam, as you suggest.
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  139. @res

    Elsewhere what appears to be a diagram of the dam, source uncertain but it looks like the power tunnel outfall isn’t terribly close to the spillway.
     
    That's true, but if you look at the (50 foot interval?) contour lines there doesn't appear to be much slope in the river between those two points--making Steve's water backing up over the turbine outlets because of spillway debris theory plausible. I wonder what design goals/requirements for turbine outlet clearance are? If there are any before/after pictures of the turbine outlets available those would be more conclusive.

    Here is an interactive topo map of the area: https://www.topoquest.com/map.php?lat=39.53803&lon=-121.50088&datum=nad27&zoom=4&map=auto&coord=d&mode=zoomin&size=m
    If I read the map correctly it shows the route of the powerlines. Running them across the emergency spillway slope seems like a really bad choice.

    The debris from the spillway formed a mini-dam in the river, raising the water level of the Feather River at the power station to high to spin the turbines. Currently, they are dredging the river and they are easing off on the water down the main spillway to 80k cfs in hopes of getting the power house outlet (13k cfs) started again.

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  140. Anonym says:
    @Anonym
    Many is my calculation.

    Primitives can count 1, 2 or many. Such is it with the imperial system, that vast empire consisting of the USA and Liberia.

    Yes I realize you are being facetious.

    Actually now I think about it, Liberia is non-Metric, but probably not Imperial. I tried to find out before, but it looked to take too much work.

    So the Imperial system holds sway in the vast empire consisting of the USA, at least, only in the non-technical parts of the USA, and thus it has been for a long time. Consider the A10, first flown in 1972 – built around a 30mm rotary cannon. Or consider the 5.56mm NATO round. When it has to work, people who work with numbers for a living use metric.

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  141. BB753 says:
    @Steve Sailer
    The metric system is better.

    Had there been a second Carter presidential term, America would have gone metric, or so the legend goes. Canada did go metric in the late seventies, with both systems still in use, which makes for a smooth transition.

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  142. Anonym says:
    @Steve Sailer
    The details of how the emergency spillway might fail are important, such as a leak versus a collapse. I have a vague hunch that if the spillway is going to go they's blow a hole in the parking lot next to the emergency spillway at the end of the way from the top 30 feet of the dam to drain the lake into the Feather River at a point maybe two miles below the dam. What you really don't want is the top 30 feet, or 450,000 acre feet falling all once 600+ feet down into river only a mile below the dam. That would probably generate a mini-tsunami that boils back up and hits the un-armored downstream front of the dam, which could be very bad.

    Yes. I am not sure how far below and what quality bedrock is situated around the edges of the dam, but it seems to me that an ideal emergency way to diffuse the situation is to find an area where there is good bedrock a few feet but not too far below the maximum height of the dam, that leads to a relatively uninhabitated valley along its extent. Then blow a channel wide enough that it can flow enough to exhaust the flow of water that the maximum rainfall is likely to deliver. It would be best if this were not anywhere near the business end of the dam, as you suggest.

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  143. Austrian says:
    @Anonym
    I am not sure it would be 10 bar at the hole itself. On the bottom of the reservoir, 10m in any direction, about 10 bar. Certainly if there were no hole, also 10 bar. But with a hole suddenly water would be pouring out at a great velocity that should initially be identical in both cases (though the smaller reservoir will drain more rapidly, so the pressure and velocity drop is much faster over time). 10m below the pipe, while one wouldn't want to be standing under it when the hole is opened, if one were in the stream itself moving along with it, it should be at atmospheric pressure or close to it. Consider that water can be considered to be incompressible, so if it's above atmospheric it can instantly expand to not be at 10 bar any more, and this is done with minimal movement. Thus it should be at atmospheric at that point. Using the same logic, it is possible that the pressure is also at atmospheric in the water stream only 1m below the hole.

    The Bernouli principle states that an increase in the speed of a fluid occurs simultaneously with a decrease in pressure or a decrease in the fluid's potential energy. (That is the only thing I have googled btw, I didn't want to embarrass myself by getting it wrong.) (The beauty of schooling is at least you remember what you need to look up, or how to find the info.) So you can see that 10m inside, the rough hemisphere of equal velocity is moving very slowly compared to the 1m hole at the bottom. The pressure should be roughly at 10 bar. But as we get closer to the hole, the velocity increases, and the pressure should be dropping. At the hole itself, parallel with the bottom of the reservoir, the velocity should be at a maximum due pressure other than the increase due to acceleration due to gravity below the hole. So that may well be at atmospheric too, but immediately inside the pressure starts to increase.

    My gut feeling in this case is to not be 100% sure of my reasoning but to try and replicate the experiment with a pressure gauge and make sure I am not embarrassing myself, but I think this is something of a trick question and I am on the right track, if not correct I am close to it. The devil is in the details with these things and it's best not to be too sure except in the approximately static case. Someone who does fluid dynamics as their bread and butter would be a lot more sure than I am.

    Total pressure = dynamic pressure + static pressure. It still adds up to 10.

    I just now realized that David Davenport was reacting to ThreeCranes’ considerations of inflow, outflow, pressure, etc. ThreeCranes seems to claim that outflow will eventually match inflow, because of the pressure increase it provides.

    But this is not true. The outflow velocity depends entirely on the water depth. The volume does not matter.

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    Total pressure = dynamic pressure + static pressure. It still adds up to 10.

    Thanks. That's useful. It has been well over a decade since I took those classes.

    Did the original problem specify total pressure or static pressure? I would think most people would be thinking static pressure in this case, and that would be the intent of including the hole in the reservoir in the question. But I could be wrong.
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  144. Anonym says:
    @Austrian
    Total pressure = dynamic pressure + static pressure. It still adds up to 10.

    I just now realized that David Davenport was reacting to ThreeCranes' considerations of inflow, outflow, pressure, etc. ThreeCranes seems to claim that outflow will eventually match inflow, because of the pressure increase it provides.

    But this is not true. The outflow velocity depends entirely on the water depth. The volume does not matter.

    Total pressure = dynamic pressure + static pressure. It still adds up to 10.

    Thanks. That’s useful. It has been well over a decade since I took those classes.

    Did the original problem specify total pressure or static pressure? I would think most people would be thinking static pressure in this case, and that would be the intent of including the hole in the reservoir in the question. But I could be wrong.

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  145. @Hippopotamusdrome
    1. 160 pounds per square inch
    2. 2998 inches of mercury

    Hippodrome:

    Thankee for not answering in Muggles measures, a.k.a. metric, the unit system of globalists and would-be speakers of Esperanto.

    I must also ask, have you been an authentic jazz man and MENSA member?

    The US Dept. of Def. uses both English and metric measures, plus knots and nautical miles. OK, knots may count as English units.

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  146. Anonym says:
    @Anonym
    Btw here is some analysis not in the thread.

    Volume = 4.3km^3
    Mass = 4.3 billion tonnes water = 4.3 trillion kg
    Height = 235m
    Avg Height = 118m

    Potential energy = mgh = 4.3 tril x 9.8 x 118 = 5 E 15 Joules

    1 tonne tnt = 4.2 E 9 Joules

    Therefore energy in dam is 1.2Mt of TNT.

    Strategic nuke incoming!

    (Hiroshima was 15kt. Tsar Bomba was 57Mt.)

    Please check my math. I originally forgot to convert tonnes to kg, so I had 1.5kt originally.

    In looking at the Banquio dam and doing similar math on that one (coming up with a significantly smaller result), I thought to recheck things here. It turns out my source for the volume is wrong. :/ Oroville actually holds 59MT.

    Plugging the numbers back in, I get:

    GPE = 59E9 kg * 9.8 * 118 = 6.8 E13 Joules

    tonnes of TNT equivalent = 6.8E13/4.2E9 = 16kt TNT.

    So it’s very similar in energy to the Hiroshima Little Boy bomb. It’s what’s referred to these days as a tactical nuke. So that’s less alarming. I’m sure the people of Hiroshima were happy to know they got hit by a relatively small yield device.

    I’ve worked out a formula to quickly calculate an estimate of Gravitational Potential Energy for a dam’s reservoir in terms of kt of tnt.

    E(kt) = 1.17 V * h
    Where V is dam volume in km^3 and h is total dam height in m. Note that you can easily convert via google, e.g. type “convert 59000000km^3 to m^3″ and it will spit out the answer.

    Due to the funnel shape of reservoirs (not too many overhangs in natural features), this will underestimate things as most of the volume is going to be in the upper half of the height range. It may underestimate the GPE by nearly half the true value. But like astrophysics and nuclear physics, getting the order of magnitude of the result is the most important thing.

    The largest reservoir of a dam in the world (ignoring natural lake augmentation) is the Kariba dam. That holds 185km^3 volume and is 128m tall. Plugging that into my formula, the yield is 27,705kt of TNT. 27Mt. So that’s about half a Tsar Bomba. A dam failure flood has the “beauty” of not wasting all that energy into the upper atmosphere like Tsar Bomba. The flood spreads out efficiently wiping out everything in its path. That’s the reason ICBMs have been designed to get more efficient devastation with a dispersed cluster of lower yield devices. Tsar Bomba was impractical as a weapon – just a combination of nuclear engineers indulging their inner 14yo boy and Cold War dick waving exercise that Stalin went along with.

    Thus, now that (I think?) I have correctly come up with a formula to estimate dam potential energy in terms of kt of tnt, it is no surprise to me that wikipedia states about this dam: “Along with the devastation of wildlife in the valley, the Zambezi River Authority estimates that the lives of 3.5 million people are at risk.” Even 3.5m people isn’t going to put a dent in the African population explosion. A Detroit in every neighborhood, the dream of Bono.

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

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    The other thing to realize is that once a dam is breached, the water will flow until it can be dispersed over a plain, meets another reservoir-like structure or lake that can hold it, or it reaches the sea. So the if you know the dam height above sea level, that's the maximum gravitational potential energy. If it's significantly above sea level, just substitute that height in the formula and double the result.

    The Banqiao dam was 0.492km^3 and only 24.5m high. 14kt. 171k deaths. By contrast Hiroshima was 90-146k deaths. That works out quite well.

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

    I would think that the damage is going to be more proportional to the volume of water than the energy, because once a wall of water is above 5m or so, if most of the population lives in houses they are going to be dead. Higher energy releases would be better for taking out modern large buildings, provided they are not too far from the wall of water.
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  147. Anonym says:
    @Anonym
    In looking at the Banquio dam and doing similar math on that one (coming up with a significantly smaller result), I thought to recheck things here. It turns out my source for the volume is wrong. :/ Oroville actually holds 59MT.

    Plugging the numbers back in, I get:

    GPE = 59E9 kg * 9.8 * 118 = 6.8 E13 Joules

    tonnes of TNT equivalent = 6.8E13/4.2E9 = 16kt TNT.

    So it's very similar in energy to the Hiroshima Little Boy bomb. It's what's referred to these days as a tactical nuke. So that's less alarming. I'm sure the people of Hiroshima were happy to know they got hit by a relatively small yield device.

    I've worked out a formula to quickly calculate an estimate of Gravitational Potential Energy for a dam's reservoir in terms of kt of tnt.

    E(kt) = 1.17 V * h
    Where V is dam volume in km^3 and h is total dam height in m. Note that you can easily convert via google, e.g. type "convert 59000000km^3 to m^3" and it will spit out the answer.

    Due to the funnel shape of reservoirs (not too many overhangs in natural features), this will underestimate things as most of the volume is going to be in the upper half of the height range. It may underestimate the GPE by nearly half the true value. But like astrophysics and nuclear physics, getting the order of magnitude of the result is the most important thing.

    The largest reservoir of a dam in the world (ignoring natural lake augmentation) is the Kariba dam. That holds 185km^3 volume and is 128m tall. Plugging that into my formula, the yield is 27,705kt of TNT. 27Mt. So that's about half a Tsar Bomba. A dam failure flood has the "beauty" of not wasting all that energy into the upper atmosphere like Tsar Bomba. The flood spreads out efficiently wiping out everything in its path. That's the reason ICBMs have been designed to get more efficient devastation with a dispersed cluster of lower yield devices. Tsar Bomba was impractical as a weapon - just a combination of nuclear engineers indulging their inner 14yo boy and Cold War dick waving exercise that Stalin went along with.

    Thus, now that (I think?) I have correctly come up with a formula to estimate dam potential energy in terms of kt of tnt, it is no surprise to me that wikipedia states about this dam: "Along with the devastation of wildlife in the valley, the Zambezi River Authority estimates that the lives of 3.5 million people are at risk." Even 3.5m people isn't going to put a dent in the African population explosion. A Detroit in every neighborhood, the dream of Bono.

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

    The other thing to realize is that once a dam is breached, the water will flow until it can be dispersed over a plain, meets another reservoir-like structure or lake that can hold it, or it reaches the sea. So the if you know the dam height above sea level, that’s the maximum gravitational potential energy. If it’s significantly above sea level, just substitute that height in the formula and double the result.

    The Banqiao dam was 0.492km^3 and only 24.5m high. 14kt. 171k deaths. By contrast Hiroshima was 90-146k deaths. That works out quite well.

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

    I would think that the damage is going to be more proportional to the volume of water than the energy, because once a wall of water is above 5m or so, if most of the population lives in houses they are going to be dead. Higher energy releases would be better for taking out modern large buildings, provided they are not too far from the wall of water.

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  148. Anonym says:

    I need to list my sources. I think I need a nap.

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

    Ok, so wikipedia lists “The dam impounds Lake Oroville, the second largest man-made lake in the state of California, capable of storing more than 3.5 million acre-feet (4.4 km3)”.

    4.4km^3.

    Plugging that into my formula, I get 1.17 * 4.4 * 235 = 1210kt = 1.2Mt.

    Ok, according to that my original estimate was correct. Sorry.

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