Sorry for lack of details.

ADS is Advanced Drainage Systems and seems to me they manufacturer their own products HDPE- High density Polyethlene. It seems expensive and carries a 100 year guarantee.

I also made a mistake and used inch symbol instead of feet so the downstand is 16 feet high and the drain pipe is 102 feet long. It was constructed 55 years ago and has rusted out. The top of the downstand has dropped 6 feet and our 5 acre pond has dropped the same level. I
intend to replace the whole system because I have read several times that trying to plug old drains is not usually successful.

The present system which we never had any problems with, has a 22" diameter downstand and a 18" drain to outlet. I want to stay close to this ratio of sizes for the new installation. I am digging out the old pipe, cutting a 4'x4' core and installing antiseepage guard around the pipe.

I would like to know if there are suppliers of pipes, plastics, which would have water tight pipes with downstand, 90 elbow, reducer coupling to the smaller drain pipe and anti-seepage guard. I am making my own trash and beaver guard above the top of the downstand.

I am looking for durable yet economic pipe with built-in system for antiseepage guard. Suggestions for brand of pipe and/ or suppliers of pipe for drainage systems in dams.