Pond Boss Forums POND CONSTRUCTION Renovating a Pond or Lake? Stand Pipe Quick Question

I am converting my siphon system to a standpipe because I added about 3 feet on top of my dam and I wanted to just use the existing pipe. It is 12" schedule 40 PVC. I cut the pipe on the water side and added a 90 degree elbow. I am planning on adding a 36" piece of 12" pvc horizontally of course in the elbow and let the water build up to that point in order to raise the water level in my pond. Here is the question. I am thinking about NOT gluing the 36" piece into the elbow so that if I ever wanted to drain down the water ( the 36") I could just pull the piece out. So do I have to worry about the pvc floating and pulling out of the 90 degree elbow or somehow coming loose? Any body done this before? It seems like an easy way to partially drain the pond if ever needed. Thanks!!!

i doubt you could pull a 12" piece out very easily, but it you did get it out i think it would be a very dangerous situation. there is a chance it could suck you in. lots of force on a 12" hole sucking water with 3 ft of head pressure.

Rather than not gluing the stand pipe, consider if it is possible to add a saddle to the pipe down low so you can add a valve of a smaller size (3-4") for draining. Alternatively, you could replace the elbow and stand pipe with a water control box. These are what I have used.

https://www.agridrain.com/shop/c85/water...rol-structures/

Warning - Beaver will chew on the boards...

Very good advice on both Scott's and RAH's account!

An unglued PVC connection will have a way of "un-connecting" itself. I can not give you odds, but even without icy conditions and the forces involved, thermal expansion and contraction will likely work the pipe extension out of it's seat. I would consider replacing your elbow with a tee and reducing down to a 3-4" valve much like RAH mentioned.

On a cheap and easy side note...if the upward extension had no valve or control box, you could put together a pvc siphon (or pump setup)that goes over the dam, get the water level lower than the extension and cut it off should you decide to permanently drop the full pool mark.

What ever you do...Do Not get anywhere near the removal of a no-glued extension that is submerged! A quick calculation for the amount of forces involved with 3 foot of water trying to rush out of a pipe yields about 150 pounds. That's enough to "suck you to it" and could be life threatening. I envision innards coming out.

Thanks to all for your good advice! I glued the pipe into place and if I ever need to drain it I will use a temporary siphon. Better safe than sorry.

Probably a good decision