If I had it to do over again, I would locate the dam on the creek location that would provide the largest impoundment of water with the least amount of dirt work. Larger containment areas can handle heavy rains better. Also, I'd have the dam constucted as straight as posible, minimizing curvatures if practical. Curving dams require more dirt work. And, give your dam enough freeboard (height above normal elevation) to allow for rapidly rising water. It can be a fun and interesting project. Good luck to you.