Found this link on top 10 beaches and swimming holes,waterfalls, in the USA, might help some on finding new places to hunt. http://www.swimmingholes.org/related.html
Excal 1000, Excal II, Sovereign GT, CZ-20, Tiger Shark, Tejon, GTI 1500, Surfmaster Pulse, CZ6a, DFX, AT PRO, Fisher 1235, Surf PI Pro, 1280-X, many more because I enjoy learning them. New Garrett Ca
If you log onto the county website's health dept. you can usually get a list of freshwater beaches they test for E coli. There are hundreds of them usually, all prime detecting areas.