You can always call the folks at PDPiping as well. The pipe going through the dam sets you lake level. I think this is the same but stated differently. It is gravity feed system everyday. When the lake is full and water running it simply goes through the pipe and out the back. Siphon stats when pipe level is full and vent tube under water, once the vent tube catches air it will shutoff. The emergency spillway should be halfway between lake level and top of dam height ( quite a bit above the air vent if you have enough freeboard. good luck!
