Stormwater management is very complicated, important work nobody thinks about. It’s like backend software - if you aren’t thinking about it that means it’s working.

Usually, when you see a building being built, what you see as the beginning is actually the result of years of work by engineers and planners designing and reviewing drainage, transportation, utilities, emergency access, environmental impacts, and more before anyone even talks about any structures. Lots of the time, this work is performed via subdivision improvements that will incorporate a storm sewer system going to a big detention facility (e.g. that lake that’s in the middle of every suburban neighborhood) that accounts for a certain amount of impervious cover on every lot in the development and is built before the land is developed.

I work in a small enclave for the mega-rich where every residential home is essentially its own subdivision, and homeowners are shocked that the drainage design and review takes months or even years of work and requires individual drainage ponds or ranwater collection vaults, while the building itself takes a day or 2 for approval.