I plan to install an 8" siphon system in my 20-yr old pond to replace the rusty CMP which will be pumped full of grout and abandoned in place. I intend to draw down the level a few feet before starting work. I've planned to just assemble the intake screen with a cross pipe for keeping it upright, and then slide it down into the water as the piping is added, leaving it lay on the underwater sloped surface...about 35 ft. Will use 8" solvent weld joints.

A contractor bidding the work tells me the pipe must be buried or it will be damaged by the vibration of operation. I've seen info (NRCS, etc.) indicating its OK NOT to bury the pipe on the inside slope when retro-fitting like this, and I sure would prefer not to bury it as that entails too much lowering of the pond in order to excavate. I'd love to hear from anyone who has first-hand experience with such a siphon laid unburied on the sloped surface under water.

Mine is not buried on the water side but is buried at the top, across the dam and the back side. Have had no issues with this since the pond was built 2.5 yrs ago. It was a pain to get the siphon to bottom even though the water was only 3' deep at the time the pond was filling.

Thanks for your feedback. What diameter is your pipe?

When researching the system for my pond I found this page:

http://www.georgialandsales.com/blogspot/?p=145

The sketch and actual photo both show exposed pipe on the pond side. You might email the author for his insight.

8" pipe was used. it was a pain to add because of the air that was trapped in the pipe as I tried to put it on the bottom of the pond. I got it done but it would have been much easier if I would have added it before the pond had some water in it.