I don't really know. I live in Washington, though, and we sure have a lot of man-made storage ponds.

So the answer to this is HOA's....

Um, what? you say.

So here in the hill country of Texas housing developments/cities need to build so many feet of storage retention ponds per house built and impermeable roadway laid. Depending on the size of the development these are decently sizes structures and an off the cuff guess on costs is between 500k and a few million (+lost land to build more houses on) so it's a sizeable expense of developing. Cities themselves don't want to pay for and maintain these structures so they instead farm it off to a MUD/PUD.

https://services.austintexas.gov/edims/document.cfm?id=22701...

The MUD wraps up the expense of the roads, things like this water settlement area, and pools and puts the expenses on an HOA.

This drain, drain, faster faster is a question I've been keen to get to the bottom off as I live in an area covered by upcoming River Thames Scheme to help prevent flooding. As I'm doing a rewilding course I wanted to find out how much natural flood management techniques they were using as nature's solution is to generally hold water as long as possible in the landscape to slow down peak flow, as peak flow is generally what causes the worst flooding events. This also has knock on benefits helping mitigate pollution and soil erosion etc. I've been to two consultations and am still none the wiser, though I've another consultation to go to.

Whether this is tree/vegetation cover or beavers (despite being in the middle of surburban sprawl, Ealing have secured funding for beavers as a potentially cheaper solution than hard infrastructure for flood mitigation and a significant amount of the beaver costs were the fencing to keep them in despite England having some wild beavers).

Similarly I've seen the Pennine Way in the South Pennines turn into a fast flowing stream during one period of wet weather due to the inability of the land to hold all the water and houses there get flooded as well.

Obviously the clash here is between the human and natural ways of doing things, building static houses on floodplains doesn't fit with more chaotic natural solutions in a dynamicly changing landscape with increasingly erratic weather patterns...

At least recently there are a lot of projects in various places to essentially build long pipe tunnels to hold water for treatment in storms and not overwhelm treatment plants.

DC is building one, London is building one, Paris is building one to make the Seine swimmable for the Olympics, etc.