Excellent advise guys. Plan then would be to slope the majority of the pond at 3 to 1 slope directly from edge down to final depth with the exception of a single four or five foot depth flat area covered with gravel underlaid by geotextile fabric for BG spawning.

On the final depth number, suggestions seem to be that in OH I would need a minimum of 8 feet depth in 1/3 of pond. Assuming a 1 ft variation in seasonal depth, should I go down 9 feet from drain pipe level? Any advantage to deeper?

Thanks