I have about a 1 acre pond that is about 7 feet deep in the middle. It is about 30 years old. The stand pipe is metal and in decent shape inside the pond and has grate to stop debris, but the other end of the pipe where it flows out to the creek is degraded and rusting. The pipe is 8" ID. I do not want to drain the pond and replace. I thinking about inserting a heavy duty PVC that is 8" OD. I tried using a much smaller 7" OD, but it would not stay in place with the spring water flow we have right now. I do have an emergency spillway that is a couple inches below the stand pipe. In the late summer when there is less rain, the stand pipe is does not have much if any flow as the water level drops an inch below.

Is there anyone that has tried this?
What problem might this cause?
Is there method of securing the inserted pipe once installed?

Thank you

Jerry:

Slip the bigger pipe over the metal pipe. Get some long self tapping screws. Drill clearance holes in the plastic pipe, run them into the rusting inner metal pipe. Use 4-6 screws. That is only temp fix because the rusting pipe is also rusting under the ground and at some point in the future it will have to be dug up and replaced.