Its because of all the rain we got, and the rivers kept rising and rising. Cedar Rapids has gone down alot, so has Palo, but Iowa City is going to take awhile becuase teh river there goes down slowly. I live kinda near them, well, kinda near Cedar rapids, and I've been watching to news and it says that all the rain we've gotten, was too much for the rivers, so they kept going up. No one can go in Cedar rapids too look at there homes today becase they may have toxins in them.
Probobly both Phillip.
Low lying areas fall victim to flash flooding and rising rivers. Water does seek its own level. As the water moves to a river, the Mississippi for example, the overload from various smaller flows creates flooding downstream.
It could take weeks for the flooding to subside.