Roadwarriorsvt:
The only thing that I would add to what stbar said is to talk with the pond owner and see if they wanted a bathyspheric map done of the pond. That will help in designing and placing the aeration system. It will also help fine tune the amount of herbacides to use if any are required.
I ran across a pond that was supposed to be 12' with an average depth of close to 8'. Deepest part was 7' with the average depth closer to 4'.