Pond Boss Forums Thread Like Summary - New Pond Overflow Repair Troubleshooting

Pond is within about 18" of being full pool and as it started climbing the overflow pipe (n12 18" culvert pipe) i noticed it was taking water thru the double wall.

I think they accidently hit it with the dozer or something, but either way, its not significant or a structural problem, but I'd like it to be tight. My ideas were as follows:


1. Drain the pond down about 6" via the bottom discharge pipe, get the level down below the gouge. Get a clam shell coupler and fill everything with blacktop crack filler on the outside. Reattach the coupler over the cut and zip tie/ratchet strap over the outside coupler

2. Repair from the inside: N1 caulking, flex seal tape, hydraulic cement? Hydraulic cement would be my choice, but I don't know how it'd adhere to the smooth inner wall of the pipe. Additionally, water is actively/slowly dribbling down the pipe, so I don't know how well either of these options would work.

Doing it right probably means dropping the pond level and re-sealing from the outside. The entire thing will be under water once we're full, so I don't really care what it looks like.

I think I'm on my own fixing it as the pond builder has since retired and has enough health issues that I feel bad getting him back out, even though it may be his fault. I'm confident I can fix it better than he can at this point.

Drop the level and repair from the outside. Water pressure will be your worst enemy if repaired from the inside.

Changed plans when I got to the garage. Saw a bag of bentonite that we'd used in water holes for deer. The vertical stack was about 24" above the dirt/grade of the pond and about 20" below where the water level will ultimately be.

Looked/felt like someone tried to seat the vertical pipe of the overflow with a spud bar or something and got a little rowdy with it. 3" long piece of plastic on a high part of a rib was broken.

2 handfuls of bentonite and it had almost stopped. I put some on the inside as well, and it pretty well quit.

So as the saying goes, if a little is good, a lot is much better. I packed about a 12" x 24" square around the outside of the pipe, and overdid the inside as well. Then I dumped the remainder of the bag below the gash and it naturally piled up above the outside hole.

Had to be out there again this afternoon and check it. it had rained some, and the stuff had held. So i dumped 4 more bags around the overflow. the entire perimeter. The dry product was above the grade of the cut.

I did get a bunch "into" the cut as well, so hoping we're ok. They seal wells with the stuff, and its done fantastic with our waterholes in the past. Here's hoping.