Pond Boss Forums POND CONSTRUCTION Building a dam 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.

that's what I was afraid of... But I have the wet season ahead of us yet. I don't wanna have to do this in July.

I have used the couplings on double-wall culvert. (To attach a saddle-tee for a pipe connection.)

The couplings themselves a fairly leaky. However, I think the coupling would do a good job of protecting the sealant that you applied over the gouge. I think your plan should work - unless the gouge is very deep relative to your normal water level and it would be subjected to lots of water pressure.

Good luck on your fix!

Like fishingrod said, the couplings are leaky but with enough goop,( industrial polyurethane, or butyl rubber caulk) is what Id use, then use the coupling to hold it in place, probably no way to make any kind of fix hold from the inside. I realize you don't want to do this in June but it may be your best opportunity, is this in exposed pipe or in the dam? if exposed it shouldn't take too long to drain it down and fix it. I'm assuming its not a huge gouge but rather a small crack. Good Luck! let us know what worked.

I have a plan and a plastic welder I'm gonna try. Then goop and it on the outside and put the coupler on it.

If that doesn't work, i'll pull the vertical stack which is where the problem is and just put a new 18" pipe in. Probably 4-5' of pipe.

Please let us know how it works!!

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.

Have you once tried a plastic welder for repairing a pond? Can it be effective? I have been thinking about using this one for welding.