There's also one oak that I specifically left standing and built the dam around as to drop acorns for the ducks, it's base is at the outside toe of the dam... do you think that would cause a problem?
I seen that and thought that was a oak. Oaks have a large taproot that is very deep. This taproot can draw water from deep within the earth (50 gal per day if I remember correct) and is the reason why oaks can cope with a certain amount of drought.
A mature oak also starts to grow lateral roots, from which smaller, more fibrous roots emerge. These smaller, lateral roots grow beyond the tree's drip line. At times about one-third farther than where the tree branches end in a mature oak. As the oak ages, these horizontal roots serve to feed the tree for the rest of its life. During and after is life these roots present an avenue for water to follow and cause a problem.
A lot of people do not realize mature Oaks often have more volume in roots than branches.
I have a pond with a Large mature oak in the emergency run around undisturbed soil. After about 15 years root rot set in and killed the Oak. I find myself now hoping that it never becomes an issue. 20 years total since built and not any problems. So really it is hard to say if it will be a problem or not.
In the end I was just wanting make sure you are aware of what I seen in the photo.
