We are going to modify our dam to a siphon system. We currently have just an emergeny spillway and a 6" bottom drain and valve for a 50 acre lake. I understand the siphon principal. My question is "does the water have to get completely over the main pipe to get into siphon mode?" In other words, I can have multiple 12" pipes or one 24" pipe. If we use a 24" will we need a 24" rise to get into siphon, or will a partial rise with a submerged vent get us into siphon? My gut says it must mostly fill the pipe tp get there.

Ross Canant