Pond Boss Forums INTRO Questions & Observations How can I fix this leak? I

My parents had a 2.5 acre pond built in 1978. It had an overflow made of corragated pipe that went straight down and under the dam. In 2002 we had the pond dredged with a new PVC pipe put in as the overflow, the old one was filled with concrete.

For the last several years our pond will fill up, but most of the year it is several feet low, when other ponds in the are full. In the winter it can be down as much as half the water volume in a dry spell. I notice that there is a slow leak where the old pipe comes out of the dam. There are no other signs of leak anywhere. There are some trees on the backside of the dam but there is no sign of leak except from the pipe. I don't know how the leak is feeding into the pipe. How should I go about fixing this? Thanks.

Welcome to the forum.

If you are in an area of the country that experiences freezing weather during the winter, the water might have froze around the concrete in the old pipe, expanded and created a void. Once the ice thawed, the water will go out that way. Can you clean out the old pipe as best you can and pump in hydraulic cement?

If heavy equipment can get to the area where the old pipe goes thru the dam, maybe it could be dug up, clay compacted in that area and that might take care of the problem. You might not have to dig up the whole pipe, just enough of it to break it and get a part of it out of the dam. Like pinching off a water hose to stop the flow of water.

Thank you for the kind welcome and your detailed response.

I do think I could get somebody in there with an excavator and pull the pipe from the dry side of the dam. I don't know if I could do it without being cost prohibitive. I would not want to have to drain the whole pond to fix the overflow pipe on the pond side. Right now it is a very slow leak. I wonder if they start pull the pipe if it would turn faster?

This part of Virginia is heavy red clay that makes for good damn material. I guess I need to find if there is anybody in the area that is good with pond work.

I was hoping that pipe could be effectively capped somehow.

Capping it is like putting a bandaid on the hoover dam. Well that's kinda drastic but you get my drift..

They might not have to pull the whole thing, just dig up a 4'-5' wide section in the center, basically cutting the pipe in half (removing the center section), then re-packing that part of the dam.

If you cap it, it still allows the water to pressurize the inside of the pipe 1/2 psi for every foot of water depth), and could possibly leak out and run along the outside of the pipe. If that happens, then the integredity of the dam could be compromised in short order.

There's going to be some loggers thinning pines next month...I could probably get them to clear off the trees from the back of the dam to where I could get an excavator in there.

I imagine I need to find an excavator that knows something about pond work. Any suggestions on how to find somebody from the area that would do a good job? I live a few hundred miles away. The guy that did the dredge work 12 years ago did an average job, but pissed by parents off over a few customer service issues, so I wouldn't go back to him now.

Go to the county NRCS office where your parents live and ask them for a list of pond builders. Then start calling 'em.

I talked to somebody at the NRCS, and he said they do nothing with ponds. So I got a reference from the county ag agent. Before I could meet him, we get 10" of rain this week. I'm sure the pond is now completely full for the first time in months (it usually fills briefly in spring and then slowly goes down the rest of the year). For cost effectiveness, I would rather have work done when it is on the low side.

I realize that this will not be an easy fix. So, while the heavy equipment is out there, I am thinking of just having the front end dredged. They would probably need a load or two to finish the repair. I would estimate they could probably pull 20+ loads pretty easily. What to do with all that dirt.....I am thinking of having them grade it on the back of the dam to make it less sharp of a slope and easier to mow. Also, the cavity blow the pipe that used to be the overflow, as seen in the pics above....have that filled in. Any reason that would not be a good idea?

I had loggers clear the back of the dam when they were cutting pine on our place this spring....much easier to access now.