Originally Posted by Fel
I'm sure we've had wilder and longer storms in the past, more rainfall, etc... but the difference is how much water fell in such a short amount of time. If we had the exact same rainfall spread over a day, it wouldn't have been a big deal. Because it happens over a few short hours, the volume of water on the ground was just too much for the city infrastructure to handle...
city infrastructure is DESIGNED to keep water in the streets, ponds, etc. before sending it into the rivers, in other words, it is designed to control the flow, not to just get rid of it. that's why streets flood.