Pond Boss Forums POND CONSTRUCTION Building a dam New pond in the holler.. a saga

No just the opposite. Well, sort of. I think a standpipe helps pack the water into the horizontal pipe by the large vertical fall before going horizontal. A standpipe can also have a sort of collar on it so it takes water from the bottom of the pond..... The collar is above the top of the highest water level, and extends down to near the bottom of the pond where the horizontal pipe goes thru the dam. The area of the gap between the collar and the pipe is equal to or larger than the drain pipe. The inner stand pipe sets the desired water level of the pond. If the water in the pond is higher than that, then the water that goes into the overflow pipe comes from near the bottom of the pond, or at least the level of where the pipe goes thru the dam.

With the way the OP had the pipe thru the dam, the pipe had to be completely covered with water before it would act as a siphon. Without an anti-vortex device, it most likely wasn't as effecient as it could have been.