Another interesting thing is that if there is water it tends to move around a lake. Some locals say its to do with the moon & tides. Others say its wind. We rang Dr Karl about it and he didn't have an answer.
It's definitely wind.
Quite correct. Wind set up on shallow lakes with a long run can be quite spectacular, and once started, seiches can continue oscillating for quite a while after the wind has stopped. They can go back and forth or in a circular motion, like you get if you move a basin of water in a circular motion.
I flew as pax on one of the Willie Ck. aircraft last year and found the whole operation very professional. (They also kindly let us use their workshop to carry out repairs to the tour company's mini-bus.)