Water is a natural get away for waterfowl....they can escape from most things if they can get to it and it is large enough for them to swim away. A creek will not work, the coon will only come across it...you will see raccoons in water all the time washing off food and what not. A pond is better so the ducks can cross it and not be taken by the coons or anything else. I had a dog one time that literally swam across the pond in hot pursuit of the goose, but I saw the dog and called it back.