@Woodcrafter: Your system (below) is almost exactly what I was attempting to describe. The only difference is that it drains bottom-water through the dam rather than routed through an existing overflow structure.


Originally Posted By: Bronco Billy
Some of the water I have is under pressure- about 42psi.
42 psi at the pipe-opening? What is the pipe's diameter? >to get an idea of the pipe's flow-rate..
Depending on the answer, it might be possible to create a bottom-diffuser using water forced through a vertically-oriented venturi-device.
I've never seen or tried it; just an idea.