It's 12 inch PVC. The siphon does have a standard type air vent, the attached drawing doesn't show it.
In my view, a pond siphon spillway is a tool to ensure the levee is never overrun with water and the emergency spillway is rarely, if ever utilized. I can appreciate having the inlet as low as reasonably possible to draw brackish water but not at the expense of greatly compromised siphon flow. Am I off base with this assumption?
That 6 foot underground "V" on the downslope was the pond guy's idea. I don't see any positive about doing that. :-(
