Rangersedge,
I know what you mean about the valve. But there is an easy fix for that. I tried drawing a crude picture of the siphon that we installed. We used 2" pipe. The downstream end is about 2' lower than inside the pond. We used a pump to fill the pipe, and ditch witch to burry it about 1' below the surface of the road on top or the dam. If you keep the pipe full, all you have to do is open the valve to start draining your pond. At the rate it was going, it looks like I could drain my 2/3 ac pond in two to 3 days.
