..... so we would not have to bore into our dam to install a siphon system, .....
Welcome to PBF Clint,
I'm not a pro but I don't think you need to bore into you dam to install a siphon. My understanding is installing a siphon is probably one of the least invasive ways to install a drain.
Again, I'm not a pro. Hopefully, someone with more experience will chime in.
Bill D.