Here's a placemark that I created that contains three beaver lodges in Silver Lake, near O'Fallon, Illinois. The lake is almost totally covered in lilly pads, but the beaver lodges continue to be well maintained. Here where the weather gets very warm in the summer the lakes are prone to algea blooms and lilly pads, particularly if the lakes are formed by ground water and not running streams.

http://bbs.keyhole.com/ubb/showthreaded....&PHPSESSID=

Rick Marshall