I can not speak for your location, but I can tall you what I do.
I do mine .25 ac and smaller and not deeper than 4' so we can sein out to move to ponds for winter forage. I build a driveway on the low side where I am going to make the pond before building (do this so the silt does not travel down stream and silt will settle back into the forage pond). I put a flow pipe just like in a drain pipe thru a regular drive at where I want the water level to be. I make sure to keep it above the high water line on the lower side so fish can go down stream and predator cant go up. Here is a pic of the last one I built foe the BCP this winter.
