When I built my house, I put in a basement with 9' high ceilings. Doing so, I apparently put the floor level of my basement (not a walk-out type) within 2' of a flood plain. Therefore, I had to get all sorts of certifications that my house wasn't in a flood plain or I was going to be forced to buy flood insurance! Since I live close (3 miles) to the Ohio River, our flood plain maps are crazy. They were drawn up nearly 100 years ago and some areas shown as being in the flood zone are over 40' above it now (but the home owners there are forced to buy flood ins.) and other areas are now well into the flood elevation but don't have to buy flood ins. because their area is shown on the old maps as not being flood prone. (These areas are mostly mobile home parks that are built in an area where dirt has been taken for decades to fill other areas. During recent rain storms, some of these areas had over 5' of water in their trailers!)
I think the recent events will force a little more attention to updating flood maps and making proper adjustments.