I spoke with Merdav and hope he won't mind me sharing some of the converstaion. His pond is located on Long Island, New York.
That being said, there are restrictions on him that would make most of us here go postal. No possibilty of dredging or draining exhists. The water source is not even really known, possibly from a spring or ground water table.

We are getting a chance to be VERY creative here in finding solutions that are not outrageously expensive.

Let's get out the tin foil hats and get creative, as it appears our percentage of smaller (forgive me) Koi-type pond owners is increasing. I think their knowledge can help us a great deal and visa-versa.