I am new to this site. I in the process of building a pond. I am looking for input on a siphon spillway, with an overflow secondary spillway. I have done some research, but need a few questions answered. Pond with be approx. 1/2 acre in size, average depth of 5 feet, about 900,000 gal. of water. Spillway will be 6" sch40 PVC 2 1/2 feet below top of dam. discharge pipe is 5 feet below that level on the outside of dam. Does the intake pipe have to be above or below the discharge level? or does it matter?

Any information is greatly appreciated.

Mike Shaw

Nope, it won’t matter. What puts it into siphon, and is the driving force through the system, is the elevation difference between the water level in the pond and the outlet elevation. You should be fine.

Good luck!