The challenge is that it just doesn't flood often enough to justify investing in significant defenses. If this were the type of event that occurred annually, or multiple times a year - I'm guessing we would see investments in the sorts of thing that Tokyo builds such as https://www.bbc.com/future/article/20181129-the-underground-...
I was disappointed to hear the term "100-yr flood" with the latest storem because I remember at least two other such floods in the area in my life -- one was in 2012 (Hurricane Sandy) And one was ~1992 (a Nor'Easter.) So that is three in thirty years. Is our distribution incorrect, or is "100-yr flood" just a media term? Or is it a way to make something sound rare so we can justify unpreparedness?
Of course, all three of these were different things -- one a Nor'Easter, one a Hurricane, and the latest was the effects of a Hurricane down south.
It's kind of an abuse of the term. The technical definition is a storm that according to historical records has a 1% chance of happening in any given year. So you'd expect to see it at least once in 100 years. As climate change increases the severity of all types of weather those level of storms will get more common than in the past in a hard to predict way. The storm percentages are also based on the historical record instead of future predictions so it will inherently lag behind the expected increasing storm frequency/intensity.
I wish they'd talk about it in these terms. It's easier to think about the cost/benefit of investing in mitigations when faced with "you have an n% chance of incurring m billions in damage this year" vs "x billion dollar damage storms should only occur once every y years".
"A common misunderstanding is that a 100-year flood is likely to occur only once in a 100-year period. In fact, there is approximately a 63.4% chance of one or more 100-year floods occurring in any 100-year period." [1]
Which is different than "You'd expect to see it at least once in 100 years."
However, yes, the expected value of the number of 100-year floods occurring in any 100-year period is 1.
The flooding from Sandy was due to extreme high tide, not due to rain. Lots of places away from the sea (like Queens) were bad this year but fine in Sandy, while places close to the sea shore (like Staten Island) were devastated with Sandy but no problem this year. So multiple threats which is bad.
Another way of saying the same thing is enough people just havent died to justify the cost. We can't keep reasoning about how to safely build cities by how much money is justifiable. It's madness.
It is a city on the ocean, surrounded by bays and lakes. The investment is justified. The political will, however, remains to be seen.
Why do you believe this? It seems it depends heavily on
- How many people would be injured or killed by the event.
- How much financial damage the event would cause.
For example, if nobody ever dies, and 10 million in damage/problems occurs each time the event does, then it's almost certainly not worth spending 1 billion dollars to to fix the problem.
Obviously, those numbers are ridiculous, but the point is there. The numbers need to be considered.
And yes, human life is a number, too. It's just harder to quantify because there's a lot of opinion involved. But if it the expectation is that such an event will kill 1 person each time, and it would cost 1 Trillion dollars to fix/prevent... it's almost certainly not worth fixing. It's harsh, but spending a Trillion dollars for a single life would be unreasonable.
Now those numbers are actually pretty reasonable. If Nobody ever dies, there's 10 million in damages each time an event like this occurs (around once every 10 years now), and with climate change we can expect the intensity + regularity to increase over time, then 1 billion is likely a good price to pay for solving the problem.
Now with mitigations like those that would be used here (like the storm water systems used in Tokyo), the sooner you implement them, the easier/cheaper they'll be to implement/maintain long term.
At the end of the day the best time to start adding the mitigations is now and expand later as necessary rather than wait until the cost is high enough and go into a mad dash to complete them before the next disaster.
Edit: For context, the Metropolitan Area Outer Underground Discharge Channel in Tokyo cost 2 Billion USD to build and is able to easily handle this volume of floodwater.
I was the original poster suggesting the Tokyo System - but I did the math and I was wrong.
The total underground capacity of the Tokyo consists of the Cans, (250K cubic meters), Cistern (248K cubic Meters) and Tunnels (575K cubic meters) - for a total underground capacity of 1.07 million cubic meters.
New York City was hit by 35 Billion gallons of rain during the flash flood, which = 132 M cubic meters. The Tokyo System has .38% of the capacity of the rainstorm, and is capable of draining at 200 cubic meters/second which would take 7-8 days to drain all that water.
What happened in New York was epic - and no underground system imaginable would have been able to handle it. The only solution to this type of problem occurring in the future is going to be around things like zoning (don't build where it's going to flood), landscape (lots more greenery), architecture (lots more void decks, first floor resilience to flooding, no basement suites, etc...)
I believe this because when I see people dying from living in flooded basement apartments -- a *well known*, documented risk of flooding from natural disasters -- I don't see "the cost was not justifiable", because it would have cost almost nothing to save their lives.
I'm not saying we can prevent any/all deaths -- that is impossible. I am saying I want responsible planning and policy that centers human life, not money, as the very point of all this planning and spending in the first place. But some of the deaths, such as the basement situations, from this disaster were very needless and do not cost trillions to prevent.
When I visited home it just happened to be around the time of Sandy. It wasn’t just Sandy itself but some other tropical remnant that dumped 7 inches of rain in two or three days? I tell people in the SF Bay Area, 7 inches is about a third of what we usually get in a year. These kinds of storms seem to be happening every ten years now rather than a hundred. (Meanwhile the West is in a constant state of drought).
Large coastal cities have issues because they lack elevation over sea level making high capacity drain channels alone ineffective. They need huge pumps to handle storms like this and buffering water ends up being significantly more cost effective. Critically pumps break down whole absorption is more resilient.
Soils have limits to their absorption. July was the wettest one in recorded history in NYC, August was the 4th wettest.
And Ida dropped over 3" of rain in a single hour - the highest ever recorded (and >7" of rain for the day - 5th highest ever recorded).
The ground was already saturated and unable to absorb much more before Ida showed up. I don't think any realistic amount of additional absorption-based strategies would have accomplished much here.
Absorption isn’t limited to soils capacity. A basin in Central Park could have held 7” of rain * 1.3 square miles until it was absorbed by the soil. Change nothing else and there would have been significantly less flooding.
“ The floodwater cathedral hidden 22 meters underground is part of the Metropolitan Area Outer Underground Discharge Channel (MAOUDC), a 6.3 km long system of tunnels and towering cylindrical chambers that protect North Tokyo from flooding.”
This kind of hidden engineering is just amazing. I love finding out about huge construction projects like this that you might never even notice. Just under your feet… making the world work.
People died due to illegal basement apts in NYC. Why was the subway open during the height of the storm? Some of the solutions are to mitigate risk to human life by prevention.
I don’t think these landlords should have the privilege to refuse willing tenants at any price without paying handsomely for the wasteful privilege of keeping potential homes off of the market.
The vacancy rate is generally low in New York. During Covid, it rose as high as 10% in Manhattan, as many well off people left the city, but at the end of 2019 the vacancy rate in the entire city was just under 2%. The easy way to tell that there isn't enough housing is to think about how many people live in undesirable living situations such as living in an illegal basement or having a roommate in a 1 bedroom apartment. That's how we fit as many people we have into the space that is available.
It takes anywhere from 8-12 hours to "shut down" the NYC subway, which doesn't really mean shut down but to park trains in the safest locations possible. NYC's subway is run 24 hours a day (most lines, most days) and even when "shut down" for Covid–19 last year ran ghost trains overnight.
Through late afternoon the predictions seemed to be a higher than normal but manageable 2-3 inches of rain (5-8cm). By the time the serious nature of the storm was apparent it was too late to shut down the system or safely park the trains.
Why does it take 8-12 hours to shut down? Serious question, not being snarky, just... the "dumb guy confidence" thing is to say "just stop the trains".
As the trains move through the tunnels, they move a large quantity of air with them. I wouldn’t be surprised if that air movement was a critical piece of the ventilation/heat dissipation strategy for some equipment located down there.
I don’t have a ready article to link to but there might be some from when Sandy hit in 2012. Basically: there isn’t enough safe space to park all of the trains when they know the system might flood. They could just stop trains where they are but then they have to get people to/from the trains and there’s a risk that any given train may develop a fault and block the line it’s on.
It’d be better if they could just park in the train yards but several are at sea level.
“The shutdown is a matter of complexity and risk-management for the MTA. A key objective for the agency on Sunday: moving thousands of buses and subway cars out of low-lying parking lots and yards that could be hit by a storm surge, including the 148th Street Lenox Terminal yard in Harlem and the Coney Island yard in southern Brooklyn, the largest rapid-transit yard in the U.S.
On Sunday, MTA workers were moving trains from low-lying areas to safe underground storage spots, including express tracks on the more than 700-mile subway system. Workers also secured vulnerable electronic equipment that could be susceptible to the corrosive saltwater of a storm surge.”
Water has been the weak point of NYC for as long as I’ve lived here. Anytime there is a good downpour the water goes straight into the subway. Most of the underground portions have open vents that go almost straight up from the platforms to open grates in the sidewalks - only slightly offset so that you can’t drop stuff directly onto the people from above. Rust and limescale is everywhere from all the groundwater penetration.
On the elevated lines the drains on the tracks are perpetually clogged with trash. It only gets cleaned out a couple times a year and then they only run a giant vacuum over it - nobody actually tests the drains. I tried to report clogged drains a couple times - I even sent pictures showing two foot deep pools of water where the drains are located but the response was “That’s normal”.
On the bright side running thousands of gallons of water through the subway is probably the closest it gets to a real cleaning. The people who spend thirty seconds mopping the first and last cars at the terminus stations don’t accomplish much.
43 comments
[ 4.1 ms ] story [ 117 ms ] threadOf course, all three of these were different things -- one a Nor'Easter, one a Hurricane, and the latest was the effects of a Hurricane down south.
We do it all the time with e.g. cloud SLAs.
Which is different than "You'd expect to see it at least once in 100 years."
However, yes, the expected value of the number of 100-year floods occurring in any 100-year period is 1.
[1] https://en.wikipedia.org/wiki/100-year_flood#Probability
I'm not as familiar with NJ as I am with NYC -- but in NYC we had something similar in 2012 and again in ~1992 with a Nor'Easter.
I'm just wondering if the risk distributions were' using are unrealistic?
https://slate.com/business/2019/01/chicagos-deep-tunnel-is-i...
It is a city on the ocean, surrounded by bays and lakes. The investment is justified. The political will, however, remains to be seen.
EDIT: clarity
- How many people would be injured or killed by the event.
- How much financial damage the event would cause.
For example, if nobody ever dies, and 10 million in damage/problems occurs each time the event does, then it's almost certainly not worth spending 1 billion dollars to to fix the problem.
Obviously, those numbers are ridiculous, but the point is there. The numbers need to be considered.
And yes, human life is a number, too. It's just harder to quantify because there's a lot of opinion involved. But if it the expectation is that such an event will kill 1 person each time, and it would cost 1 Trillion dollars to fix/prevent... it's almost certainly not worth fixing. It's harsh, but spending a Trillion dollars for a single life would be unreasonable.
Now with mitigations like those that would be used here (like the storm water systems used in Tokyo), the sooner you implement them, the easier/cheaper they'll be to implement/maintain long term.
At the end of the day the best time to start adding the mitigations is now and expand later as necessary rather than wait until the cost is high enough and go into a mad dash to complete them before the next disaster.
Edit: For context, the Metropolitan Area Outer Underground Discharge Channel in Tokyo cost 2 Billion USD to build and is able to easily handle this volume of floodwater.
The total underground capacity of the Tokyo consists of the Cans, (250K cubic meters), Cistern (248K cubic Meters) and Tunnels (575K cubic meters) - for a total underground capacity of 1.07 million cubic meters.
New York City was hit by 35 Billion gallons of rain during the flash flood, which = 132 M cubic meters. The Tokyo System has .38% of the capacity of the rainstorm, and is capable of draining at 200 cubic meters/second which would take 7-8 days to drain all that water.
What happened in New York was epic - and no underground system imaginable would have been able to handle it. The only solution to this type of problem occurring in the future is going to be around things like zoning (don't build where it's going to flood), landscape (lots more greenery), architecture (lots more void decks, first floor resilience to flooding, no basement suites, etc...)
I'm not saying we can prevent any/all deaths -- that is impossible. I am saying I want responsible planning and policy that centers human life, not money, as the very point of all this planning and spending in the first place. But some of the deaths, such as the basement situations, from this disaster were very needless and do not cost trillions to prevent.
Fixating on absorption is not effective and much more costly.
And Ida dropped over 3" of rain in a single hour - the highest ever recorded (and >7" of rain for the day - 5th highest ever recorded).
The ground was already saturated and unable to absorb much more before Ida showed up. I don't think any realistic amount of additional absorption-based strategies would have accomplished much here.
the more trees and roots that exist in that dirt, the more quickly water is drawn away by capillary action (you see, the roots are a series of tubes…)
“ The floodwater cathedral hidden 22 meters underground is part of the Metropolitan Area Outer Underground Discharge Channel (MAOUDC), a 6.3 km long system of tunnels and towering cylindrical chambers that protect North Tokyo from flooding.”
- https://www.bbc.com/future/article/20181129-the-underground-...
Last checked at least 10% of NY apartments sat empty (landlords holding out for rents to go up).
https://www.wsj.com/articles/manhattans-apartment-vacancy-ra...
Through late afternoon the predictions seemed to be a higher than normal but manageable 2-3 inches of rain (5-8cm). By the time the serious nature of the storm was apparent it was too late to shut down the system or safely park the trains.
It’d be better if they could just park in the train yards but several are at sea level.
“The shutdown is a matter of complexity and risk-management for the MTA. A key objective for the agency on Sunday: moving thousands of buses and subway cars out of low-lying parking lots and yards that could be hit by a storm surge, including the 148th Street Lenox Terminal yard in Harlem and the Coney Island yard in southern Brooklyn, the largest rapid-transit yard in the U.S.
On Sunday, MTA workers were moving trains from low-lying areas to safe underground storage spots, including express tracks on the more than 700-mile subway system. Workers also secured vulnerable electronic equipment that could be susceptible to the corrosive saltwater of a storm surge.”
On the elevated lines the drains on the tracks are perpetually clogged with trash. It only gets cleaned out a couple times a year and then they only run a giant vacuum over it - nobody actually tests the drains. I tried to report clogged drains a couple times - I even sent pictures showing two foot deep pools of water where the drains are located but the response was “That’s normal”.
On the bright side running thousands of gallons of water through the subway is probably the closest it gets to a real cleaning. The people who spend thirty seconds mopping the first and last cars at the terminus stations don’t accomplish much.