It also shows that we have paved over too much soil. Cities hardly have any ability to soak up extra water. Whenever I walk outside in a stronger rain and I see the torrents of water gushing over the hard surfaces directly to the closest gutter, I can't help but think that our ancestors would judge us pretty harshly for treating rainwater like nuisance and not a resource to manage wisely.

It wouldn't have helped in this case, though. No clever water retention system can cope with such a downpour. Maaaaybe it could mitigate the worst results.