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A bigger problem than ISIS: The Mosul Dam is failing (newyorker.com)
406 points by anigbrowl on Dec 26, 2016 | hide | past | web | favorite | 172 comments

Stunning picture showing a portion of the huge amount of water behind, at 300 ft higher: http://www.globalconstructionreview.com/client_media/images/...

Wow, amazing to see that much water and no greenery surrounding it.

Haditha Dam seems to be similarly impressive:


I guess it doesn't have the same structural problems, related to a bad soil.

Dexter Filkins, the writer of this piece, is also the author of one of the best non-fiction books I've ever read - The Forever War (not the space war book).

The Forever War https://www.amazon.com/dp/0307279448/ref=cm_sw_r_cp_api_OWDy...

You've got to be kidding me. I started reading "The Forever War" (the space war book) based on some comments I read on here and I assure you that there wasn't any warning about the space war book.

Haldeman's space war book "forever war" is rather good though.

If you want a good space war book, Cixin Liu, Three Body Problem and sequels.

The Forever War (not the space war book) is excellent however.

The Forever War (the space war book) is also excellent

Does the author typically write in such a narrative form? I had a hard time finishing this piece and normally very much enjoy descriptive writing. Perhaps it could have been more succinct.

This is common for long-form New Yorker articles, not just this author.

You really should consider reading Ian M Banks's Culture series novels if you like that. He's widely considered to be the best sci-fi author in the UK (He's scottish).

I'd certainly put the culture series close to par with Ender's Game and the Dune novels. They're most excellent.

Start with Consider Phlebas. It's the easiest to start with, but also not completely representative of what the series ends up being. I highly recommend Banks.

Most definitely. I recommend reading them in the order that they were published, which starts with Consider Phlebas. I also put Player of Games in the top 10 best Sci-fi books I've ever read I just enjoyed the ending of it so much.

Banks is an incredible author.


was =(

And Alastair Reynolds. Former ESA scientist, so even his space opera feels truthy.

Also really enjoyed that book. The stories about the treatment of third country nationals (essentially contractors from countries like the Philippines and India working on US bases) were surprising and saddening.

I have a close friend that is is the Army Corps of Engineers at the dam. Despite being deployed to the dam months ago, she's seen sporadic time at the dam due to ISIS in the area. Every time they even get close the higher ups decide to evacuate the American engineers, can't say what's been decided for the others. During the recent Mosul Offensive, they were away from the dam the entire time.

She was also telling me that during the time that ISIS held the dam, they managed to booby trap the entire place. They had multiple Iraqi workers killed in bathrooms from traps set. However, ISIS didn't manage any real structural damage to the dam.

> ISIS didn't manage any real structural damage to the dam.

This makes it sound like they were intentionally trying to destroy the damn, were they?

I'm not an expert but it seems like it should be easy for a military group controlling a damn to blow it up if they wanted to. Though the article mentions that it was built to be resistant against air strikes, so maybe not?

She said all the booby trapping happened in the last days as the US was about to recapture the dam, so it was hastily done. That being said, it did slow operations as they then had to sweep the entire dam after they realized what happened.

She said it would have been pretty difficult for them to cause significant structural damage, because as mentioned it was 'bomb proof' and as stated they were making money up until the very end in selling electricity.

Particularly since the article mentions that the electrical generation from the dam puts money in ISIS's pockets.

Amazing read, much longer than I generally get hooked into.

I am astonished that "Grouting" (A term i find like many in the engineering word makes a possibly questionable practice sound like a good idea) is a functional, let alone acceptable solution, I can only begin to imagine what the ground under that dam must look like after the last 20+ years of concrete being poured into it.

"Amazing read, much longer than I generally get hooked into."

Please, please subscribe to the New Yorker in some fashion ... I personally subscribe to the kindle version which is a very useful and workable format.

The New Yorker[1] regularly has very, very good long form articles that have deepened my understanding of what I consider to be very important issues. Off the top of my head, I can think of three such articles that stick out - their long treatment of the deepwater horizon accident and the chemical dispersants that were used in the cleanup, their decade-after-the-fact retrospective article on Gore vs. Bush, and a more recent article on the police officer who shot Michael Brown in Ferguson, MO.

[1] Also the London Review of Books which is excellent for long form current events articles. Also book reviews.

I often find when I do get lost in an article, it's common to be something from the New Yorker. The articles are very well written and often explore the story in a way that is factual and creative that I really enjoy.

Reading "Precedent and Prologue" (Gore V's bush supreme court article) I got so interested in the judicial activism concept and ended up lost on Wikipedia for a few hours bouncing around related articles. The exact same thing happened to me with this Mosul Dam article, when I saw myself reading about Gaddafi I realized I had gone so far down the rabbit hole that the topics I was now reading about were only vaguely related.

All said and done, it's a good point i really should become a paid subscriber, thanks for suggesting it!

it's gotten a lot of buzz lately, including on HN, but if you're interested in going down the gaddafi hole a bit further i'd recommend the recent adam curtis film, hypernormalisation. his films tend to be a bit like getting lost in a wikipedia hole in their own right, though.

You have to be a little careful though - https://youtu.be/x1bX3F7uTrg

Adam Curtis does make some generalisations but i am not sure its possible without them. The world is so complex that anyone trying to understand the topic would have to go through same research Curtis had to. Its so hard to make point about global situation in 3 hours.

It is a political commentary and sometimes its subjective but i think his work make lot of people think and investigate. That's whole lot better than something that tries to be objective no matter what - that always ends up saying practicaly nothing.


Then watch Only The Dead (see the end of a war) by an australian bloke

Good luck sleeping afterwards

No joke, just finished watching HyperNormalisation[1].

The most depressing part to me is that Adam Curtis isn't off on an easily dismissed tangent in this documentary, he's essentially cross cut the last 40 years into a 3 hour cliff notes guide to some of the darker corners of postmodern philosophy.

Specifically, Baudrillard. His 2002 essay, The Violence of the Global[2] has some interesting food for thought:

>We believe that the ideal purpose of any value is to become universal. But we do not really assess the deadly danger that such a quest presents. Far from being an uplifting move, it is instead a downward trend toward a zero degree in all values. In the Enlightenment, universalization was viewed as unlimited growth and forward progress. Today, by contrast, universalization exists by default and is expressed as a forward escape, which aims to reach the most minimally common value. This is precisely the fate of human rights, democracy, and liberty today. Their expansion is in reality their weakest expression.

HyperNormalism is bleak and offers no solutions for course correcting international affairs, and there's the rub: universal solutions may not exist.

For me, my mind's left reeling by the complexity of the times, leaving me at a loss for how to integrate information from sources like Baudrillard into my worldview guiding day-to-day behavior. My typical response is a hyperlocal focus on the people around me in meatspace and trying to at least get the basics right like the golden rule.



The New York Review of Books is also wonderful. I prefer it to the LRB, though they share a bunch of contributors, and they're both great.


If you believe that you should not read main stream news (like I do) this is one of the sources to get 'good' news from.

I don't mean to knock on The New Yorker or cast aspersions on your choices, but I have two rebuttals:

First, longform articles such as this one usually come months or years after the fact and don't help with the primary mission of journalism, which is to keep you abreast of the goings on around you. (Of everything from "what your local government is doing and how that affects you" to "what the financial markets in another continent are up to and how that affects you.") This is my opinion, but I think that the pejorative "mainstream media" is often used as a substitute for "media that doesn't write a story how I want it written."

Second, The New Yorker is owned by Advance Publications, which is about as "mainstream" of media as you're going to find. One of their larger publishing subsidiaries is Conde Nast, which publishes The New Yorker alongside Architectural Digest, Vogue, Golf World, GQ, and several other publications. You may also know them as the publisher of ArsTechnica. They also own more than 40 newspapers.

Just my two cents, for what that's worth these days.

"First, longform articles such as this one usually come months or years after the fact and don't help with the primary mission of journalism, which is to keep you abreast of the goings on around you."

I think journalism needn't only tell you what happened, but also why (in the opinion of the journalist) it happened. The latter requires reflection and/or research, so it cannot come directly after the fact.

I even think the why is more important than the what, as what doesn't give you enough information to react. For example, "X threatens to go to war with Y over Z" may mean just that, but also "X wants to show Y they are really concerned over Z" or "X wants to win the next elections, so it shows the electorate what it wants to hear". How other countries should react is quite different.

longform articles such as this one usually come months or years after the fact and don't help with the primary mission of journalism, which is to keep you abreast of the goings on around you

I think there are many facets to the mission of journalism. In-depth and investigative journalism are very important as well as being kept up-to-date on what's happening in the day-to-day. In some cases I prefer these more in-depth pieces as they have some perspective on how the events they're describing are affected by historical context and how they are affecting what's going on in current events. Consider the Woodward and Bernstein's Watergate coverage or the Boston Globe's coverage of the child sex abuse by Catholic priests in Boston.

Different events and issues can be served by different forms. For a piece like this, I have a hard time imagining it being served better as a short piece of a couple column inches in a paper or a 90 second segment on the evening news. Not all events need coverage like this, of course, but it doesn't make the long-form pieces any less an important and vital aspect of journalism.

> For a piece like this, I have a hard time imagining it being served better as a short piece of a couple column inches in a paper or a 90 second segment on the evening news. ... it doesn't make the long-form pieces any less an important and vital aspect of journalism.

I agree and I should have written more words that are like what you wrote. The New Yorker is great for what it is, in-depth coverage of a complicated or unfamiliar topic. I suppose my point was that other, more general sources ought, in my opinion, to be part of a "balanced diet" of news coverage.

There's some interesting criticism of whether "current events" news really provides any actual societal value, or if it might actually do the opposite [1].

[1] https://www.theguardian.com/media/2013/apr/12/news-is-bad-ro...

I am not knocking you, AP or Reddit here, but I think your examples should also include Reddit, the private corporation. AP are still the majority stockholder.


The Atlantic has good long-form pieces as well: https://www.theatlantic.com

I discovered The Atlantic when I was in high school and fell madly in love with it. It helped that it was ridiculously inexpensive, something like $14 for 2 years (yes, I'm old).

That magazine and The Economist (which I loved but couldn't afford a subscription to) kept me much better-informed than I am now, when I'm old and jaded and happier being ignorant.

The Atlantic actually remains about that cheap, particularly with their regular sales. I've never paid more than $1/issue. They, like many other magazines, seem to have moved to a model of doing whatever it takes to keep print circulation up, thereby being able to charge more for ads. They've also been significantly more successful with their web presence than a lot of their peer magazines, which also compensates for the low subscription cost.

One of the first steps in many building foundations is injecting concrete into the soil, typically in the form of pillars.

Desperate times probably call for desperate solutions in this case.

When I looked up "grouting" on Wikipedia, I learned it's a process most dams use.

But presumably only once.

Interesting, is there any work done to first evacuate the area of soil or is it simply pushed out of the way using pressure from the concrete?

Don't know, I guess it depends on the depth, for small buildings you just hammer the concrete pillar in - https://www.youtube.com/watch?v=VkXTLAxGKxA

I'm surprised you never witnessed it, I've seen this at least 3-4 times. Probably because nowadays constructions sites have big opaque fences around them.

This is not grouting. This is driving concrete piles.

Grouting refers to multiple things when talking about foundations or underground work but here are some examples:

Jet grouting - high pressure water/grout/air is used to displace and mix the soil and grout to make a soilcrete

Compensation grouting - grout is injected under pressure into the soil in order to displace/heave the ground to counteract previous settlement

Cutoff grouting - grout is injected into the ground in order to cut off ground water

What they're doing at the dam appears to be backfill grouting where they are injecting grout from within the dam underneath it trying to cut off the seepage path of the voids that have formed. This appears to be because they've built the dam on a soluble rock and so voids are constantly created which allow flow paths. They must find the voids and fill them with grout. This is a never ending process until all rock is replaced with grout.

But, how can they do this forever? They can't encase most of the reservoir in concrete?

I recall my dad talking about something similar regarding the reconstruction of a building where he worked after and earthquake. I suspect I've heard it and passed it off as general construction noise, but not seen it due to the fences you referenced...interesting!

I've seen those, but always assumed they were driving steel beams into the earth. I'm surprised that concrete can be manhandled that way without being smashed into pieces.

Driving concrete piling has generally been abandoned in USA/Canada/Western Europe due to the propensity of concrete to crack in tension during pile driving operations. Driven pile is typically steel now in most construction you will see unless you live in a place where concrete is extremely cheap compared to steel.

The steel pile-driving process is also extremely loud and creates a lot of vibration, so it's all but extinct inside urban areas.

All the projects I've seen here in recent years, and there are hundreds, use caisson holes, wide, bored holes going straight down, to create the basis of the foundation. Once drilled, they insert steel and fill it with concrete. The equipment resembles a very large-scale post-hole digger.

It seems to be fairly quick and work quite well: http://www.rwhengineering.ca/?page_id=2518

Although the drilling machines are somewhat loud, they're an order of magnitude quieter than the pile driving machines. The amount of banging those machines would generate was absolutely nuts.

Wouldn't that be to crack in compression?

Also, I don't see concrete piles being abandoned at all. Part of the reason may be that, where I live, many poles now are drilled, pressed or vibrated into the ground to decrease noise and potential impact on surrounding buildings.

Thats is possible because there is no bedrock to build on where I live, so poles often go down easily for the first meters; I have seen wooden poles sink in five meters or so under their own weight.

Traditional piling into the ground still is used, too. If necessary, a protective head cover on the pole (made from wood or, nowadays, plastic) softens the blows a bit, protecting the concrete from damage.

No, tension is what I meant.

Imagine the pile hammer hitting the top of the pile. This impulse is transmitted down the length of the pile at the speed of sound as a wave. There exists a point where the wave gets to the end of the pile (this is at the pile tip) and the compression front attempts to continue which results in tension (eg - the pile tip is dragging itself forward with the energy). This is mostly seen with soft soils where end reaction is not sufficient to provide a hard "stop" on the pile.

For hard ground, the opposite can occur where the driving energy reflects at the pile tip. This can result in huge compressive forces that crush (not crack) the concrete due to the two compressive waves (one new wave from the next hammer strike and the reflected wave from the previous hammer strike) stacking due to superposition.

The reason that this failure mechanism wasn't noted by me is that steel piles suffer the same issue, so it is not a good reason to use steel over concrete piling.

As you note, the solution to both issues is the use of a shoe and control of the hammer stroke.

I should have been more clear, I guess. Driven concrete pile is not used in the USA/Canada in my experience. When deep concrete foundations are used they are typically drilled in, for the reasons cited above.

There are obviously times when concrete piles are cheaper and will get the job done even with the risks above. This is most likely for smaller buildings where loadings are relatively light and pile lengths are therefore short.

Not sure about your statement...

In the Netherlands this is still done quite often because the soil is too unstable. Concrete piles are driven into the weak soil until it hits the sand. Houses are typically built on top. The pole can be protected with a wooden block that due to the friction can set fire.

Amsterdam is known to be built on wooden piles that remain intact as long as they stand under water: pumping away the water will cause the piles to rot and the houses to sink away.

My understanding is that concrete resists the compression of the ram impact well, but the shock wave reflects back and causes tension which then triggers failure. This tension is the point that needs to be controlled.

In that case what I've observed was probably steel after all. Thanks.

Keep in mind that despite the term "drive", the concrete piles are usually vibrated into place. It is not like driving a fence post with a sledge hammer. Obviously there is still a lot of stress introduced to the concrete column, but it is designed with the stresses in mind. The reinforcing steel takes a lot of the load during the placement process.

Maybe it looks something like gargantuan concrete anthill art.


Way down the bottom, we see the problem is solved for at least the next year:

"Early in 2016, under American prodding, the Iraqis reopened negotiations with Trevi S.p.A., the Italian firm. In September, a team of engineers, hired at a cost of three hundred million dollars, arrived at the dam to perform a crash repair job. Their main task is to install updated equipment, designed to fill the voids beneath the dam more precisely, and to repair the broken control gate. Under the contract, the Italians will do the grouting for a year, and then leave the equipment with their Iraqi counterparts. The engineers say that they are confident they can prevent the dam’s foundation from washing away."

The sentence folllowing that starts with But. 'Crash repair job' also doesn't instill confidence that it is a given this will work.

Also, this dam still is close to a war zone, if not in a war zone. That updated equipment may not make it there, can get destroyed in an attack, or the personnel doing the work can be 'persuaded' not to work or may outright be killed.

What surprises me most about this story is that they kept delivering power to the enemy, while they also could have let all or most of the water out. It wouldn't surprise me if money or backstabbing ("we'll keep delivering electricity if you focus on attacking your other enemies instead of on getting back the dam from us") was involved there.

This has been a pattern that has been seen over and over in Iraq. Contractors come in an build "state of the art" infrastructure to repair or replace existing infrastructure. This in itself is not a problem per se. There are two issues.

One is the local population lacks the training and expertise to run and maintain this "state of the art" infrastructure. Not that they couldn't become capable because they certainly could but their frame of reference is maintaining 40 or 50 year old infrastructure.

The second issue is that they don't have the financial means of maintaing this newly installed infrastructure. Their operating budget often can't accommodate the maintenance of such state of that art infrastructure. What's good for a first world contractors bottom line is not necessarily the best fit for a third world country's utility company.

This book details a lot of this and is worth a look:


I've heard though that, until the war at least, Iraq had a fairly top-notch science and engineering corps.

I'd speculate that this might be due to Baathist secularism and militarism, as well as the areas legacy of being arguably the intellectual center of the Muslim world.

I'm not sure if your point is applicable here. This is a dam from 1986, not some new fangled contraption no one understands. It has a known maintenance schedule and is old school technology. The problem is, ISIS decided to murder or chase off the staff who maintains the dam and didn't keep up with the work it needs.

Worse, the construction was done "on the cheap" as dictated by the Hussein regime. Instead of digging deeply into the delicate and soluble gypsum and grouting properly, the engineers were forced to use a shallow blanket-grout technique which simply requires more maintenance going forward as it failed to stop dissolution. Grouting on this dam is done six days a week. That's right, every day but Sunday since 1986. ISIS's pause of this created this crisis.

Contrary to your point, if it was done "first world style" it would be a much more stable dam, but instead the Hussein regime was too busy buying palaces and gold toilets to care too much about getting large scale projects right. Iraqis now much pay forward the technical debt of the shallow blanket grout until the dam is decommissioned. There is no alternative here and this dam should be a study of autocratic regime's attempts at cost savings which ultimately cost more in the long run and may eventually cause a human rights disaster. I believe 1m people are at risk of drowning if this dam collapses. These are non-trivial numbers.

Iraq had a lot of money back then and like in much of the developing world, mega-projects were sought after (and not just by despots).

The Mosul Dam was not built cheaply, it was rushed to completion to meet some idiotic deadline. The other options would likely not have cost much more (especially considering maintenance), but it would have taken more time.

And it was "first-world style", the consultants and construction firms were European just like the ones that built Kariba Dam. They had no problem building it nor any problem cashing the cheques.

The article says the dam was rushed because of the war with Iran that Saddam Hussein started in 1979.

Saddam had the crazy idea that he could conquer the Middle East and make Iraq into a world superpower. So he started a war with much larger Iran, the war stalemated and went on for 8 years, with enormous loss in human lives, and enormous debts piled up on the Iraqi side. That ended and Saddam invaded Kuwait to get its oil riches, leading to the Gulf War which Iraq quickly lost.

Saddam still wanted to build an empire, so he prevented full nuclear arms inspections to keep the rest of the Middle East afraid he still had a nuclear arms program, and in fact planned to re-start it after the inspection and sanctions program ended.

That lead to the Iraqi war, which Iraq quickly lost, and left Iraq so divided and disorganized that ISIS could arise and take much of the country, including temporarily taking the Mosul Dam. And the disorganized, corrupt government has bungled dealing with the threat of the dam collapsing, and so we are in the present, very dangerous situation.

So it all goes back to Saddam Hussein, and the generally poor political situation in Iraq, and beyond that, I would say, the Middle East as a whole.

From the article it sounded like they were upkeeping the dam just fine, until ISIS came through and chased off the workers and maintenance wasn't performed. But I haven't read that book and this is just one article, just genuinely curious cause that seemed like a discrepancy.

Or, the existence of a functioning dam is of benefit to ISIS so they are less likely to destroy it (causing a catastrophe) than they would be if electrical supplies were cut off (?).

ISIS, being famously known for not doing things against their best interest.

It would be of a great benefit for them to see the dam destroyed, if they could convincingly pin it on the Iraqi government and/or Western countries.

The article also says many experts are scared to death it is going to collapse, and a chart of dangerous dams puts it much higher than any other. I bet that one of the conditions the Iraqi government insisted on including in the contract with Trevi S.p.A is that it says to the public it is sure it can prevent a collapse.

I think people should trust independent experts much more than companies under contract from a very corrupt and incompetent government. Don't you agree?

> Kurdish officials intended to shut down the turbines, but American officials told them that this would add more water to the reservoir, making the dam more likely to burst. So isis continued to profit from the dam. “We wanted to strangle them, but we weren’t allowed,” a Kurdish official told me.

Not that destroying infrastructure and killing the power to a city of civilians, despite ISIS control, is necessarily a good idea, but could they not just cut the lines?

> Not that destroying infrastructure and killing the power to a city of civilians, despite ISIS control, is necessarily a good idea, but could they not just cut the lines?

Do you know what happens when you run a turbine with nowhere to put the load? 750MW is enough to boil something like a kiloton of water every hour, that energy needs to go somewhere.

Honestly - no, I don't know what happens. Can you tell me? I mean without any modifications that would specifically covert that power into heat, what would happen with the lines cut? Something like the turbines melting, or welding themselves to the structure?

The turbines are Francis type which means they keep spinning until the water flow is stopped.

When a generator is disconnected from the power system without first removing the power from the shaft then power in is greater than power out and the result is an acceleration of the generator. Generators are built to be able to withstand a certain maximum rotational speed without flying apart for a certain duration of time before the bearings get too hot. Of course it can operate at the normal speed forever, but the rated over speed might be twice as fast for 10 minutes.

So when the power lines are cut the turbines and generators speed up until the flow of water is stopped. Pictures of the Mosul dam show four surge tanks, one for each turbine, so they can probably turn off the water in 5-10s.

Pelton turbines are used for higher head and the flow can be maintained without turning the turbine by deflecting the water away from the runner.

I've commissioned about a dozen hydro electric power plants and opening the breaker to simulate cutting the transmission line while making 10, 25, 50,75,100% of the power is standard procedure.

Thank you very much for the expert information. but that still doesn't make sense to me. The article states they have two control gates and a spillway. (one gate previously defunct but now repaired) So, shouldn't it be possible to block off the turbines and open the control gates instead, so that the total flow stays (roughly) the same?

Moreover, if the dam is indeed that easy to destabilize, letting ISIS control the load seems equivalent to handing them a big red "trigger flood" button for use at their discretion. Sure, right now it's in their interest to keep the dam intact - because they still control many parts of Mossul and need the electricity. But "scorched earth" is not exactly a new concept and if the operation in Mossul continues as planned and ISIS is driven out, they could decide to cut the lines on their end to deliberately cause mechanical failures.

I haven't re-read the article, but I recall the control gates were at the bottom of the dam. Traditionally the spillway is at the top of the dam and on one portiona there are gates which are operated hydraulically or by winches that open to allow water to pass underneath and run down a specially shaped (ogee shape) face of the dam. If for some reason the water level behind the dam gets too high there can be a section of spillway with no gates that will allow water to flow around the dam without the dam being overtopped in an uncontrolled fashion.

The mosul dam is 113 m high and the article said they were operating the dam with the water level 30m below the normal full level. Probably the sill of the spillway is only 10 or less below the normal operating level, because if the dam isn't full why would you want to spill.

The control gates at the bottom of the dam could have been primarily for allowing sediment to be sluice out from behind the dam or to allow the reservoir to be drained.

There is no guarantee the two control gates could pass as much flow as the turbines. Who knows how they were sized.

As I tried to explain before, cutting the power lines shouldn't damage any equipment. It effectively happens all the time due to natural causes, be they tree branches falling on power lines, birds, squirrels, etc.

Flow through an orifice (sluice gate, control gate, turbine, etc) varies with the square root of the pressure of water (the head), so a side effect of operating the dam with 30 m less head (30% less!) is that the turbines would be operating outside of their normal range and the control gates would pass less flow than they would at the nominal head.

There was a terrible accident at a dam in russia that was caused by operating the turbine outside of the normal range of pressure, and poor maintenance (loose bolts holding the turbine down...):


That's exactly right. Either that or a catastrophic mechanical failure. It's really not an experiment you want to do. One way or another, it would be both ugly and irreversible.

My vague understanding of a turbine was that it was a spinning magnet, so if you killed the circuit it would just... spin, I guess.

If this is a concern, why isn't there a worry that ISIS or just a stray bomb would kill the power lines when retreating from Mosul? Though I suppose they could just target the dam itself...

> My vague understanding of a turbine was that it was a spinning magnet, so if you killed the circuit it would just... spin, I guess.

The load in the circuit acts as a brake. If you kill the circuit, the turbine spins faster and faster until it breaks into pieces. To prevent that, the control systems stop the water from flowing into the turbine, but stopping the water from draining is the opposite of what they want.

The story suggests there is a 300 foot wide canal that can be used to let water go in casse of an emergency. Well, how about doing so now? Rather than using the turbines, use the canal to let the water out, but without it generating electricity...

The emergency spill way is in case of a large rain or melt event that brings the water level up quickly. The spill way is used to ensure that the dam is not over topped, which is usually catastrophic. As such, the spill way is usually placed at or near the maximum safe free board (distance from the top of the dam down to the water level). What this all means is that the spill way can only be used when the water level in the reservoir is allowed to get to high and possibly dangerous levels. The article stated the the water level has already been decreased by 10 meters which means that the spill way is going to remain dry for a long while.

Next time you are near a dam look around and you will find that most have three paths for the water to leave the reservoir. The first is through the power generating turbines, second is the sluice gates which control water level, and third is the emergency spill way which is designed to fend off catastrophic failure.

Open a valve that DOESNT go through a turbine?

A dam should have something like that....

I think the only equivalent is the floodgates, but, they only work when the water level is at a certain height, and I think I've read that if you open them to a true flood point you damage the dam.

Drilling a second tunnel just to let water out is probably not considered economical.

According to the article there are two control gates and a spillway. The control gates are used to regulate the water level and the spillway is used in an emergency.

I don't know if the control gates can drain the reservoir completely or they have some minimum level, but the article implies that there is some action that the Iraqi government could take:

> Last spring, the Iraqi government prepared by lowering the maximum water level in the reservoir, to ease severe pressure on the dam wall. This year, such a precaution could dramatically lessen the number of people at risk—to about three hundred and sixty-four thousand.

What isn't clear is whether the water level right now could be lowered immediately or the water level now is at a seasonal low point and the Iraqi government hasn't announced whether they'll spill water in the spring to keep it low.

> Drilling a second tunnel just to let water out is probably not considered economical.

Economical relative to what? The projected losses if half the populated area of the country is flooded?

I wonder how much it'd cost to make a heating coil big enough to dump the energy. You've got all that water right there...

You could use it to boil some of the water away? A win/win if you're not a civilian relying on the power that is.

Well, on the assumption that it'd work...

Now you've got a dam full of boiling water. And as you'll know from cleaning dishes, boiling water is far better at dissolving minerals than is cold water.

How are you calculating that entire reservoir would boil? It's filled with 8B m^3 of water.

I couldn't find the formulas to calculate this myself, but given Tuna-Fish's comment above that it's enough to boil a kiloton of water (1000 m^3) ever hour that's 1K/8B =~ 0.00001%.

So it's going to be more on the order of dropping a single drop of boiling water into a backyard pool every hour, is it not? I.e. something that wouldn't change the overall temperature of the reservoir to any significant degree.

This is all assuming that you'd have to use the energy to heat the reservoir itself, you could just as easily use it to pump out some water and boil it until it evaporates, not impacting the temperature of the reservoir at all, just emitting a lot of steam into the air.

I'm curious why you guys want to boil the upstream water instead of the downstream water.

To reduce the amount of water behind the dam. I'm sure using the power to power pumps would be a better at that task though.

You pump water into a boiler, not just submerging a giant heater into the dam.

Probably lack of sufficient dump load.

A dump load is a sign of a poor civil and mechanical engineering design of a power plant. It means the mechanical system can't change the shaft power as fast as required.

The Masonry dam in Washington state near Seattle also has/had this problem. The geotechnical reports and conditions were ignored and the water flowed under and around the dam, popping up in all kinds of places.

The dam was never able to be filled and is just called the masonry dam since nobody wanted it named after them.


Masonry dam had quite a different problem which is just that there was too much water and it couldn't keep up, so water spilled over the side about 6000ft away from the dam. The problem with the Mosul dam is that it's built on soluble rock that could be swept away with enough pressure. Yes, too much water is the cause of both failures, but they're quite different.

do you have a better link to information on Masonry dam? My information is second hand from a hydro electric turbine expert. He clearly stated to me that the dam was built in a location that was geotechnically unsuitable so water flooded underground channels due to the pressure of the water behind the dam and popped up all over the place. A nearby lake level raised a bunch. I might have got the wrong link. "masonry dam" is hard to google, as intended.

Heh, I was originally going to ask you for more information before my comment because the link wasn't the most descriptive on that incident, but briefly mentions that it happened 6000 feet away from the dam, which got me curious. I think had some more luck searching for "Boxley Creek 1918" or "Boxley Burst" which was the name of the actual incident. http://www.historylink.org/File/2426 was the first result on Google.

The caption of a picture says the reservoir holds 11 billion cubic FEET, but the article earlier says METERS.

That's a magnitude of difference.

According to Wikipedia, 11B cubic meters is the correct total capacity, with 8B cubic meters being the active capacity. Meaning, they try to keep it at 8B m^3, with 3B m^3 of flood-control capacity.

I'm curious, were you calculating or using (or thinking about, had some train of thought about) this information or did you just happen to notice the mixed units? I mean because I can't picture either one or ten billion cubic feet of water so it's just a very large number to me and I wouldn't notice that difference.

For me it helps to think about the cube root of the figure -- a billion cubic feet is 10^9, meaning a cube 10^3 feet on a side. About a fifth of a mile.

A meter is over 3 feet, so a cubic meter is over 3^3 or 27 cubic feet. You can ask google for a precise value: https://www.google.com/search?q=cubic+meter+in+cubic+feet And 10^3 meters on a side would be a kilometer.

One billion cubic meters is a cubic kilometer - a cube with each side measuring 1km. 11 of these would be a cube with ~2.25 km sides. Or slightly less than a mile and a half per side.

I never thought about the fact that a billion is "just" a thousand times a thousand times a thousand.

So I thought of something I could picture a thousand of - for example millimeters. A thousand mm is just 1 meter, so I can easily see/picture a billion of something (cubic millimeters of air) right in front of me (as 1m x 1m x 1m). Neat!

The Powers of Ten film comes to mind, helps put things in perspective as well. https://en.m.wikipedia.org/wiki/Powers_of_Ten_(film)

It's a classic, by Charles and Ray Eames.

Actually closer to two, 1m3 = 74ft3.

One cubic meter is 35 cubic feet, not 74.

Yes, but it's 74 Google+ likes, or at least that's what an online converter would have me believe: http://i.imgur.com/9xIW1wr.png

Slightly off-topic:

> Up close, the work is wet, improvisatory, and deeply inexact. [...] Like his boss, Jabouri has worked at the dam since he was a young engineering graduate. Now, he told me, he is as sensitive to the dam’s changes as the electronic gear buzzing around him. [...]

“We feel our way through,” Jabouri said, standing by the pump. Generally, smaller cavities require thinner grout, so Jabouri started with a milky solution and increased its thickness as the void took more. Finally, after several hours, he stopped; his intuition, aided by the pressure gauges, told him that the cavity was full.

The irony saddens me that, if you replaced that worker and his human lifetime of knowledge with a "data-driven control system" and his intuition with a "machine learning algorithm", we would all hail the result as the pinnacle of technology in mainantence systems - even though the data and actual descision making would be almost the same...

What happens if Jabouri gets hit by a bus? I love a good craftsman as much as anyone, but when the lives of that many people rely on one person, you're just asking for a disaster.

I'm assuming you'd deal with bus factor as everyone else who has ever relied on human labor has done -- training, more than 1 person who knows how to do a given job, etc. The world's still buzzing even though we've lived through thousands of years of people dying, I think we've had enough time to figure this one out.

It's not like the problem of training disappears with machine learning. What if the person maintaining the ML algorithm is hit by a bus? What if the algorithm needs adapting? etc.

Then someone else picks up the code and continues maintaining it. You can read through documentation and existing code. You can't extract information from a dead guys brain...

What stops a human from documenting a process in writing?

Intuition is pretty hard to document.

> human labor has done -- training, more than 1 person who knows how to do a given job, etc

Except we're not talking about standard human labor. The guy isn't building bricks, he's maintaining a damn through "feel". That's not something that can just be easily trained.

By your logic, explain why we can't buy a new Stradivarius today. Obviously we dealt with the problem of just training someone else to do the same job throughout history by your own admission. It surely isn't lack of demand so I must not be looking in the right places. Where can I buy one?

We can build violins that equal or surpass Strads in many measures. Strads are not varied because they are technically unbeatable, they are valued for the same reason art is.

>We can build violins that equal or surpass Strads in many measures. Strads are not varied because they are technically unbeatable, they are valued for the same reason art is.

We can TODAY by means of technology. There was a 200 year gap where we couldn't. And had it been something life-threatening (like maintaining a dam) instead of just producing music, we would've been up a creek without a paddle.

Previous discussion [1].

[1] https://news.ycombinator.com/item?id=11209228

I came here to note this. People bring this up every year or so - when I was in Iraq in 2006, this was an issue of the "any moment they could all die" sort but nobody seems to care enough to fix it since there isn't a firm timeline for the dam failure. Also, there's that whole war thing going on.

> In private, some Iraqis pose conspiracy theories. “I know a lot of Iraqis who think this is just a big psyops operation by the U.S. government—senior officials, not just Iraqis on the street,”

Of course. When a foreign army invade your country, then proceed to criticize your infrastructure, they make themselves difficult to listen to. Even if they are right. If Iraqis had concerns wouldn't they involved third party inspections from non-American firms?

What the Iraqis should do is not just believe every conspiracy theory that comes along, but carefully investigate each one to see if it makes sense. From what I understand, they don't generally do this.

It's hard to figure out if this event is unlikely or likely to happen.

But I won't be surprised to wake up tomorrow to learn that there's a humanitarian crisis in Iraq.

Without action, it's certain it will happen. The question is not if, but when.

It sounds like they can keep grouting forever

I'm curious to what ratio an abusive regime is affected by general sanctions vs the populace under its authoritarian control. Sad to see so many people living in poverty from a dictator, then sanctions, then an invasion, now ISIS (And a dam apparently).

I don't know what the solution is, but that area of the world just cannot find peace.

> Sad to see so many people living in poverty from a dictator

Iraq was an urbanized country with effective national healthcare, homegrown industries, plenty of agriculture and natural resources and a high standard of living relative to its neighbors before the Gulf War. However, it is true that Saddam Hussein did significant damage to the country's economy by engaging in genocide and the devastating Iran-Iraq war. His brutality in suppressing anyone he thought was opposing him was truly awful. Still, it needs to be kept in mind that the current day Iraqi economy in shambles is significantly the work of sanctions that did nothing to weaken the totalitarian regime's grip on power and an invasion that devastated the country, replaced the regime with a new kleptocratic government, and sold many of the country's resources to international entities.

> I'm curious to what ratio an abusive regime is affected by general sanctions vs the populace under its authoritarian control.

Inevitably the sanctions will hurt the general populace more than the people in power. However, that might reduce the popularity of the leader and ultimately help their downfall, perhaps.

Or it might not. It might make the populace more isolated, bitter and paranoid, more likely to stand by the leader against the perceived evil of the rest of the world. Decades of sanctions against Cuba and North Korea just entrenched the respective regimes more tightly.

I don't understand, can't they slowly empty the lake behind the dam?

The built up water is a form of potential energy and draining it would mean it is wasted.

I don't think wasting energy is the major concern in this situation

Well if the official stance is that there is no problem then why should they do that?

The problem is how long it takes to drain it, and how quick you realize the dam might break and how much time it can take.

As the article says, the dam would break very quickly without giving enough warnings.

Millions of people are depending on that water and electricity daily. Even without a violent release, I suspect draining it would bring long-term discomfort/suffering in the form of significant power loss and water shortages. How long would it take to fill back up to usable levels in that desert?

A quick calculation of what it would take to replace the dam with solar panels:

According to wikipedia the dam produces 1052MW. Let's call it 1GW. https://en.wikipedia.org/wiki/Mosul_Dam

According to quora you need about 10000m2 or one 1ha to produce 1MW. So 1000 * 10000m2 = 10km2 to produce 1GW.

I wonder how big the lake is? Could solar panels installed in the drained lake - theoretically - provide the same or more energy than the dam?

Of course energy storage is a major part of water power and it is not taken into account above. On the other hand a decentralized power grid is one of the major advantages of solar (especially in an unstable country) and that is not taken into account either.

But the damn isn't there just to provide power. Remember back when it was built Iraq exported power, in the form of oil.

It's also there to regulate the flow of the river, which commonly floods the surrounding, crop-growing region.

Yes, but according to what I can read the lake is filled to 8km3 capacity, with 3km3 capacity for flood regulation.

So wouldn't a much smaller dam be sufficient for flood regulation?

The problem isn't just one of power. It's also (ironically) flood management. That reservoir allows Iraq to store water from years of plenty (and prevent downstream flooding) for years of drought when that extra water will be needed for farming, drinking, etc.

You'd need twice as many panels because panels generate very little power at night whereas the dam continues to run.

Also you'd need a battery bank to hold half a days worth of electricity. You could try pumped storage... oh wait this is kinda the problem here isn't it, so that's not happening.

Theoretically a drought would have more sunny days and less water, so solar and dam do loosely speaking work together although the coupling isn't that tight for a long river.

I rarely like The New Yorker writings, but this is actually a good one. Importantly, because it starts with short description of a whole, and then goes into the detail. Most The New Yorker writers consider it ok to start (and continue) the article with something like: "On a warm sunny autumn day he was sitting in the park, wearing his grey merino-wool polo shirt and khaki pants".

The only thing I'd like to be explained more thoroughly: what actually is this dam? I.e., how does it work? Going to wikipedia I see a whole list of different types of dams, and it is not clear to me, what does this specific construction in the article actually do, and how its failure would cause a tsunami-like wave.

if isis can ruin more dams; why arent they a bigger problem?

Because that would not make as good headline.

Because this particular dam happens to be upstream to some large population centres, back in 2007 they estimated half-million people could be killed and several millions displaced, that figure might be higher today.

The Lewisville Dam near Dallas, Texas is also one to watch, although the scale of a potential disaster is much smaller and something is being done about it. http://interactives.dallasnews.com/2015/lewisville-dam/

Sadly there is also a dam in Africa, in similar dire position, due to being built on a geologically unsuitable site.

[1] http://www.newyorker.com/tech/elements/one-of-africas-bigges...

This is eerily similar to Bitter Lake.. http://www.dailymotion.com/video/x35szal

A bigger problem than both: the 100-1000x atmospheric mass in methane calthrates bubbling up from the ESAS that have the potential to push climate change beyond +6 ℃. Get ready for high food prices, more failed states (and more mob armed cults), regional WMD wars and mass exoduses.

It sounds rhetorical and impossible at first glance if the evidence including satellite measurements and field observations weren't so definitive. Preppers don't sound so insane at first but they're probably not thinking about sustainable semi/off-grid living in a radically-altered climate.

Article from the future? Jan 2nd, 2017

It's the issue date of the magazine it appears in, which is why it says "January 2, 2017 Issue".

The saddest part of the article is the US tried to blow the dam up during the gulf war. Why? That is as brutal as dropping the nukes on Japan.

Uh, what article are you reading? Or do you think bombing a generator is to "blow up the dam"?

The quote is: "the dam had been built to survive an aerial bombardment. (In fact, during the Gulf War, American jets bombed its generator, but the dam remained intact.)"

(A dam with bad air defense ought to be an easy target, considering all the emphasis the Americans puts into getting through lots of cement -- and that dams were bombed already during WWII.)

Edit: The shocking part was how the US found out about how much the sanctions had damaged the country -- and then poured billions into fixing it. The US politicians might waste even more than my native ones.

bombed generator not dam....bombing dams was banned under the Geneva conventions.

"According to Article 56 of the 1977 Additional Protocol I to the Geneva Conventions, “works or installations containing dangerous forces, namely dams, dikes and nuclear electrical generating stations, shall not be made the object of attack, even when these objects are military objectives, if such attack may cause the release of dangerous forces and consequent severe losses among the civilian population.”

That was never ratified by the USA or ISIS, both reserving their right to blow up dams like this one.

Yep. That is what I thought. I realize now that its strategically just to blow out the generator :)

During World War II, the Royal Air Force's Operation Chastise [1] killed about 1,600 civilians (600 Germans and 1000 Soviet forced-labourers) with specially designed dam busting "bouncing bombs" [2]. There was a discussion about bouncing bombs about a month ago [3], which went full Godwin, of course.

[1] https://en.wikipedia.org/wiki/Operation_Chastise

[2] https://en.wikipedia.org/wiki/Bouncing_bomb

[3] https://news.ycombinator.com/item?id=12961241

They didn't but we did blow up dams in WWII. In fact, the death star run in Star Wars was based on a WWII movie called the dam busters: https://www.youtube.com/watch?v=lNdb03Hw18M

Are you against the WW2 retaliation bombing of Japan by the US? If so, please, from your office chair, inform us on what the course of action should have been.

Proof please. BTW: Fake news site is not a proof.

Is there a summary of the main risks? Sounds interesting but I don't have time for New Yorker-style reporting.

"... Completed in 1984, the dam sits on a foundation of soluble rock. To keep it stable, hundreds of employees have to work around the clock, pumping a cement mixture into the earth below. Without continuous maintenance, the rock beneath would wash away, causing the dam to sink and then break apart. But Iraq’s recent history has not been conducive to that kind of vigilance.


In February, the U.S. Embassy in Baghdad issued a warning of the consequences of a breach in the dam. For a statement written by diplomats, it is extraordinarily blunt. 'Mosul Dam faces a serious and unprecedented risk of catastrophic failure with little warning,' it said. Soon afterward, the United Nations released its own warning, predicting that 'hundreds of thousands of people could be killed' if the dam failed. Iraq’s leaders, apparently fearful of public reaction, have refused to acknowledge the extent of the danger. But Alwash told me that nearly everyone outside the Iraqi government who has examined the dam believes that time is running out: in the spring, snowmelt flows into the Tigris, putting immense pressure on the retaining wall.

If the dam ruptured, it would likely cause a catastrophe of Biblical proportions, loosing a wave as high as a hundred feet that would roll down the Tigris, swallowing everything in its path for more than a hundred miles. Large parts of Mosul would be submerged in less than three hours. Along the riverbanks, towns and cities containing the heart of Iraq’s population would be flooded; in four days, a wave as high as sixteen feet would crash into Baghdad, a city of six million people. 'If there is a breach in the dam, there will be no warning,' Alwash said. ..."

It's really weird to see 'loosing' used in the correct manner online...

Thank you!

There's only one risk, that the dam will burst. Not the dam itself, but the surrounding foundations. They built it on Gypsum (has a tendency to dissolve in water), upkeep work (pumping grout into the voids) stopped for 1-18 months depending on who you ask.

"In the language of hydraulic engineering, the process eroding the foundation is known as “solutioning.” If that problem is not addressed, what happens next is “piping”: water begins to travel between the voids, moving horizontally beneath the dam."

"Schnittker told me, “Once piping begins, there is no going back. In twelve hours, the dam is gone.”"

> stopped for 1-18 months depending on who you ask

IMO, this is the scariest part of this. It's hard to make good engineering decisions in general. It's nearly impossible when there is no accurate picture of the situation.

Sorry if this is a dumb question. TBH I didn't rtfa. But if the dam needs a constant infusion of concrete in order to not fail, why wasn't anything done to evacuate the area and gracefully (sic) fail the dam in the first place?

You would have to evacuate Mosul (1.7 million people) and probably also Baghdad (7 millions), all in a country thorn by war where refugee camps are already bursting with people. Plus of course the entity that control Mosul (ISIS) is not keen on letting civilians go given their value as human shields.

But this issue with the dam was apparent before ISIS, no?

The constant infusion of concrete isn't an emergency measure. It's how the dam was intended to operate. The problem (from the planners' point of view, anyway) isn't that it requires constant grouting, it's that it stopped getting constant grouting.

It was not intended to operate this way when it was built. Maybe there was a plan to fill holes with concrete but never on that scale as was decided later. Note decided later - unclear whether ever enough grouting was done to fill the need. The stoppage of grouting was just another straw on the camel's back.

My broader point is that a dam which requires constant grouting seems like a pretty bad idea.

All dams require maintenance or they fail. You are correct in that its merely a question of magnitude. Completely abandoned, Hoover Dam for example would last a lot longer, but hardly forever. Where the line is drawn is pretty arbitrary, and if the alternative is the people have no electricity or irrigation water so they riot and kill you ... Saddam was famous for the stick but sometimes he used the carrot to keep his country together. No one is keeping it together now, of course.

The article makes it seem like everyone knew it was a bad idea to build it, but Saddam wanted it built and everyone was too afraid/being payed to not say no.

Didn't read the article, but from comments here I understand ISIS is the reason maintenance work halted.

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