How big is your pond? Do you have any other spill-way and does/would your pond have any retaining buffer before it would start going out the drain?
I can tell you from experience that a siphon of the same size will move more water. My watershed is 150 but I also usaully have a buffer to play with in my pond to hold atleast 25ac feet just in case one of those hurricanes hit. This give me some reaction time to plan what I am going to do on weather forcasts.
