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Q&A
Impact of development on stormwater management and sewer capacity
2:12:45
ยท
96 sec
Commissioner Aggarwala explains the relationship between development, population growth, and their impacts on stormwater management and sewer capacity in New York City. He addresses common misconceptions and provides technical details on the city's sewer systems.
- Development and population growth do not necessarily lead to more stormwater flooding; new developments often improve stormwater retention
- The city's combined sewer system can handle population growth without significant strain
- In separately sewered areas, the approach of distributed housing across the city is not expected to cause issues with sewage capacity
Rohit Aggarwala
2:12:45
In the combined well, we should remember, two thirds of the city is a combined sewer system.
2:12:53
The incremental sewage that results from population growth is such a small increment compared to what happens when storm water events happen.
2:13:03
So again by way of comparison, on an average day we process something around 1,200,000,000 gallons of waste water on a dry day.
2:13:13
If we get a quarter inch of rain across New York City, that's a billion gallons of storm water.
2:13:20
Right?
2:13:21
So in any so our sewers are designed to hold many times the dry weather flow which is why population growth in those combined sewer areas doesn't really change the balance in terms of flooding or overtaxing of the sewers.
2:13:37
Roughly a third of the land area of the city is separately sewered and there they are completely divorced.
2:13:44
Right?
2:13:44
So the sewage goes through one pipe that's sized for sewage.
2:13:48
And there we pay very close attention and we were deeply engaged through City of Yes where we do believe that the approach of a little housing across the city rather than highly concentrated growth is not going to tip the scale in any of our separately sewered areas.
2:14:07
We are working very closely with the Department of City Planning on some of the more concentrated rezonings, which if they are in in MS 4 neighborhoods, we do have to take that into account.
2:14:18
But again, that's not about flooding, that is about sewage capacity.