Mperry, sounds like they are just a banded water snake. There are different kinds of non venomous water snakes. They won't hurt you and are harmless.
I have never understood why anyone wants to kill a snake for fun. The thing to remember is leave it alone and it won't bother you.
A lot of people think my kids and I are crazy because we catch snakes all the time.
I caught a cotton mouth in Reel Foot last year in a boat lane. Kept it in a bucket and gave it to the viewing center across from Boyettes. They could not believe it. They said that most people just kill them.
here is a link to kind of give you an idea of the venomous and non venomous snakes of North America.
http://www.pitt.edu/~mcs2/herp/SoNA.html