I have once again conferred with my contractor and one of the subjects was the principal spillway. The spec's of the project: approx 5 surf acres, approx 35 ac/ft, 60 ac of drainage (about 40 ac of which is row crops), 36" avg annual precip.
The original plan was to utilize 2 separate 12" dia spillways. They will run for a considerable distance thru the valley we are filling in downstream of the dam. The overall spillway tube length will be 260 ft. The idea for 2 separate spillways was to cover the potential of one clogging, particularly since the pond is surrounded by heavy timber and I won't be there to watch it every waking moment.
The new thought is a hybrid of improvement with some savings. The improvement will be going to a single 18" dia pipe. The savings will be with material (likely minimal) and installation time. The 18" pipe will allow an even larger area of flow than a pair of 12's. The logic is that it if one 12" pipes is gonna clog with sticks and leaves/crap, the second one is probably not far behind. An 18" dia pipe will be less likely to clog, compared to a couple of 12's.
This all makes good sense to me. Kick back some thought, pondmeisters.
