Just to give you another example of "it depends", on my mini forage pond, I only designed the "dam" to be 1' above full pool and the emergency overflow to be 6" above full pool. So I only have 6" of safety before the dam is breeched.
But......... this pond is only about a half of a tenth of an acre, and only sees maybe an acre or two of runoff. It is near the peak of the hill. PLUS, full pool for it is only about 18" above full pool of my main pond which is right across the dam. So even if the dam were breached, the water levels would equalize pretty quickly.
Is a foot enough? I doubt if an engineer would say so. But I think it will be fine and if it isn't will have no one to blame but myself. If it were a big pond with large water inflows from a large watershed, no way would it be enough. The three acre pond I had an engineer design (NRCS). This little tiny pond I did the design myself.
So as you can see, the size of the pond, the size of the watershed, size of rainfall events all come into play of how much dam height above full pool is needed, the size of the overflow pipe, emergency overflow sizing, ect.
Last edited by snrub; 09/25/14 11:26 AM.
