How Ida dodged NYC’s flood defenses
technologyreview.com
technologyreview.com
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.
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.
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.
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.”
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-...