ewest,
I first thought of a siphon, but I want to remove the water at about 12-15' and I can't get nearly that low on the outside. And if I remember correctly, when we used to borrow gas, late at night in south Texas, the out had to be lower than the in.
Ric
The place where the water will exit is over the existing spillway, which is sort of a waterfall now, just not visible unless you are on top of it. But, I have another question, both you and Bretski mentioned a submersible pump and I was considering a non submersible. Is there an advantage with either?