two questions, california

First question: If there's a drought (and there always seems to be a drought), why does everyone insist on watering the grass until it turns into a muddy swamp? I know that you don't want your treasured green patch to dry up and die, but do you want it to drown, instead?

Second question: Why must you build your parking lots and roads to always have a ditch that is so (im)perfectly designed that it is nearly impossible not to scrape the bottom of your car when you leave the parking lot? Is the ditch there to catch the runoff from your drowning lawns?