This is an interesting issue; it makes sense that ISIS would be bad at dam maintenance.
Without reading all the sources (so perhaps these are clearly answered somewhere in there), some next questions I’d be curious about:
Where does the “500,000 to 1.5 million” estimate of deaths come from? Is this taking the simulations from the European Commission paper and assuming that anyone affected by water levels over X meters high dies?
Likewise, where do the cost estimates for the solutions come from?
Is it right that if this happened, it would be the most deaths caused by a dam failure, ever? Wikipedia seems to suggest this is so, with the 1975 Banqiao Dam failure causing ~20k − 200k deaths.
One solution would be to spend $2 billion to finish construction of Badush dam downstream in order to block the floodwaters, which if this saved 1 million lives would come out at $2000/life saved, better than AMF. Even if that’s likely too optimistic, it’s suggestive, as the likely if as yet unknown existence of more targeted marginal uses of money for readers means this is in my opinion a very promising new cause area worth further investigation, this post being an opener towards further inquiry. I encourage others to do much more detailed expected value calculations, with openminded curiosity.
I appreciate that this is just a toy estimate. But I think even at a toy level we could make the estimate more accurate by having a term for “P(dam failure within X years, absent our intervention)”. The dam may not fail within a given timeframe, or it may be fixed by other actors before it fails, etc, and it doesn’t seem like the case is so overwhelming that these outcomes should be ignored. E.g. if you think the dam is 50% likely to fail within 40 years, absent our intervention, then the estimate looks like $4000/life saved in expectation.
But I think even at a toy level we could make the estimate more accurate by having a term for “P(dam failure within X years, absent our intervention)”.
I agree that’s important, and would like to add a section for that. I did not find any actual quantitative estimates of the risk, and now think that one initial step here would be for someone to comb the research more thoroughly than I did, or survey some engineers either involved or not, or outright commission someone to model the risk of the dam.
I don’t know if other actors will fix it, though they haven’t so far in 35 years, including when the U.S. occupied Iraq.
My qualitative sense of the risk is, “This will eventually collapse at some point if nothing permanent is done beyond indefinite grouting work, which has some amount of imperfection, and no one is doing the permanent fix.”
I think this means that since the damage is cumulative, there could be some predictability to it. Probability would only increase over time. Maybe if a detailed enough simulation were done, we could get a better sense of it.
That means I would maybe put 20% on it collapsing by 2040, and maybe 60% by 2060 (without additional intervention).
I don’t know what the likelihood of outside intervention is, but I wouldn’t put it at greater than half over the next 20 years. So that puts my personal ballpark at 10% chance of collapse in the next 20 years.
We also have to include the risk of Great Power War or something else more disruptive than ISIS occupation halting the grouting work.
I would be rather worried about rough outside view calculations preventing someone from engaging with this who would have. Far better to form a physical model of what’s happening with the dam, if someone can do that (I was disappointed to see none of that IIRC with my Three Gorges Dam question). We could also model who are the likely individuals to fund a fix, talk to them to see if they have plans for that, and try to influence them, at pretty low cost.
Summaries and pointers to some primary sources can be found on the Wikipedia page I linked, which at a high-level answers these questions:
A September 2006 report by the United States Army Corps of Engineers noted, “In terms of internal erosion potential of the foundation, Mosul Dam is the most dangerous dam in the world.” The report further outlined a worst-case scenario, in which a sudden collapse of the dam would flood Mosul under 65 feet (20 m) of water and Baghdad, a city of 7 million, to 15 feet (4.6 m), with an estimated death toll of 500,000.[17] A report on 30 October 2007 by the US Special Inspector General for Iraq Reconstruction (SIGIR) said that the dam’s foundations could give way at any moment.[18]
According to The Economist, “One study says that if the dam collapses, Mosul would be submerged within hours. Another warns that half a million Iraqis could be killed by floodwaters, and more than a million forced from their homes. Disease and looting as the floodwaters raced through Baiji, Tikrit, Samarra, and even parts of Baghdad would complete that dreadful scenario.”[19] Nadhir al-Ansari, an engineer involved in the building of the dam who is currently Professor of Engineering at the Luleå University of Technology, Sweden, said that the floodwaters would take four hours to reach Mosul and 45 hours to reach Baghdad, and that more than a million people would be killed if a “good evacuation plan” were not in place.[20]
In 2004, dam manager Abdulkhalik Thanoon Ayoub ordered the dam’s water level, which can reach 330 metres (1,083 ft) above sea level, to have a maximum of 319 metres (1,047 ft), thus reducing the pressure on the structure. Nevertheless, Iraqi officials maintain that the U.S. government is overstating the risk. The Army Corps of Engineers has proposed that the Badush Dam downstream be completed to serve its purpose of obstructing the large wave that would result if the Mosul Dam collapsed. This has been resisted by Iraqi officials, who note that the current plan for the Badush Dam is US$300 million to provide hydroelectric power and help irrigation while the proposed expansion would cost $10 billion.[17]
In 2007, the U.S. Army Corps of Engineers developed and executed a US$27 million plan to help continue maintenance and repairs on the dam in the short-term. The Iraq Government was also recommended a long-term solution that includes the construction of 67 m (220 ft) deep walls around the dam foundation. The project would cost $4 billion and take approximately four to five years to complete.
If people have questions about the estimates, I recommend directly contacting and asking the authors of primary sources, if they’re available (and letting us know what you learn). I will add this Wikipedia information into the post for legibility.
None of those studies mention 1.5 million deaths. One of the studies estimating 500,000 deaths is cited as outlining a worst-case scenario. The most pessimistic estimate of 1 million deaths is conditional on no good evacuation plan being in place. More importantly, all of these studies were based on the dam’s condition before extensive repairs were carried out in 2016–2017—repairs that were undertaken to address just those safety concerns. As the Wikipedia article notes, “In May 2017, Iraqi Minister of Water Resources Hassan Janabi stated that no danger to the dam remained and it was going back to normal operation. Carlo Crippa, the project manager, said the dam structure now showed no significant signs of distress.”
This is an interesting issue; it makes sense that ISIS would be bad at dam maintenance.
Without reading all the sources (so perhaps these are clearly answered somewhere in there), some next questions I’d be curious about:
Where does the “500,000 to 1.5 million” estimate of deaths come from? Is this taking the simulations from the European Commission paper and assuming that anyone affected by water levels over X meters high dies?
Likewise, where do the cost estimates for the solutions come from?
Is it right that if this happened, it would be the most deaths caused by a dam failure, ever? Wikipedia seems to suggest this is so, with the 1975 Banqiao Dam failure causing ~20k − 200k deaths.
I appreciate that this is just a toy estimate. But I think even at a toy level we could make the estimate more accurate by having a term for “P(dam failure within X years, absent our intervention)”. The dam may not fail within a given timeframe, or it may be fixed by other actors before it fails, etc, and it doesn’t seem like the case is so overwhelming that these outcomes should be ignored. E.g. if you think the dam is 50% likely to fail within 40 years, absent our intervention, then the estimate looks like $4000/life saved in expectation.
I agree that’s important, and would like to add a section for that. I did not find any actual quantitative estimates of the risk, and now think that one initial step here would be for someone to comb the research more thoroughly than I did, or survey some engineers either involved or not, or outright commission someone to model the risk of the dam.
I don’t know if other actors will fix it, though they haven’t so far in 35 years, including when the U.S. occupied Iraq.
My qualitative sense of the risk is, “This will eventually collapse at some point if nothing permanent is done beyond indefinite grouting work, which has some amount of imperfection, and no one is doing the permanent fix.”
I think this means that since the damage is cumulative, there could be some predictability to it. Probability would only increase over time. Maybe if a detailed enough simulation were done, we could get a better sense of it.
That means I would maybe put 20% on it collapsing by 2040, and maybe 60% by 2060 (without additional intervention).
I don’t know what the likelihood of outside intervention is, but I wouldn’t put it at greater than half over the next 20 years. So that puts my personal ballpark at 10% chance of collapse in the next 20 years.
We also have to include the risk of Great Power War or something else more disruptive than ISIS occupation halting the grouting work.
I would be rather worried about rough outside view calculations preventing someone from engaging with this who would have. Far better to form a physical model of what’s happening with the dam, if someone can do that (I was disappointed to see none of that IIRC with my Three Gorges Dam question). We could also model who are the likely individuals to fund a fix, talk to them to see if they have plans for that, and try to influence them, at pretty low cost.
Could you please provide a source for the “500,000 to 1.5 million” deaths estimate?
Summaries and pointers to some primary sources can be found on the Wikipedia page I linked, which at a high-level answers these questions:
If people have questions about the estimates, I recommend directly contacting and asking the authors of primary sources, if they’re available (and letting us know what you learn). I will add this Wikipedia information into the post for legibility.
None of those studies mention 1.5 million deaths. One of the studies estimating 500,000 deaths is cited as outlining a worst-case scenario. The most pessimistic estimate of 1 million deaths is conditional on no good evacuation plan being in place. More importantly, all of these studies were based on the dam’s condition before extensive repairs were carried out in 2016–2017—repairs that were undertaken to address just those safety concerns. As the Wikipedia article notes, “In May 2017, Iraqi Minister of Water Resources Hassan Janabi stated that no danger to the dam remained and it was going back to normal operation. Carlo Crippa, the project manager, said the dam structure now showed no significant signs of distress.”