Open water swim

Quick question... I live out in Dover, and am looking for a good lake or river to be able to swim in to get more practice of the whole not being able to see anything. I was swimming at York on Mon at Stage Neck Inn cove but had the Great White sighting on the cape in the back of my head. I know I'm crazy for thinking that. Anyway where are some good open water swims? Fresh or Salt water is fine with me. Thanks and am loving this training just wish I could do a tri tomorrow.