how to manage flash floods effectively..

I’m mesmerized by what the city of tokyo and the city of dallas came up , in regards to flash flood management.

tokyo

https://www.youtube.com/watch?v=tvUgOtS4kFQ

more on Tokyo

https://www.youtube.com/watch?v=o85teh1vU_0

dallas.
if i’m not wrong the Dallas tunnel collects water from a highway of some.

https://www.youtube.com/watch?v=E49DDYXob78

huko ni low lying areas. huku kenya shida yetu huwa kutupa taka taka kwa drains tuu