I built a 1 1/2 acre pond(14ft at the dam) three years ago and my dam leaked. The contractor came back and worked on the dam and it leaked worst than before. Finally realized he had not cored the dam properly and every pond he built had problems. He will not be back and out of business.

My pond has a few small springs but rain runoff is my main source of water. It takes about 6 months to fill. I have 8" sdr-35 pipe with a 90 degree overflow that I use to drain the pond. It works but is really tough to push over to start draining. My new contractor who is well respected has suggested I put a valve on the back side of my dam on the end of the sdr-35 pipe and do away with the 90 degree overflow. He also recommended an overflow pipe through the dam at the top to drain before it hits the spillway. He is going to put in a new core at the base of the first dam and widen the dam to the appropriate width and slope. He is also adding two more anti-seep collars to the drain pipe.

Excuse my rambling but I want to give as much info as possible. Will the sdr-35 pipe work in this application with a valve on the end of the drainpipe or will it leak over time. Any suggestions? Thanks