That is alot of good info above. I have thought about Pinetar's comment about how the consultant is adament against overflow pipes. If it was me, I would ask for ponds that this consulatant was in charge of and go visit them. See how he built the spillways, and are they built properly. What does his theories look like after 10/20 years. What do the owners think. He may do a really good job, or it might make you aware that you need to really watch the situation closely and impart the knowledge shared above.
