Pond Boss Forums POND CONSTRUCTION Renovating a Pond or Lake? Hole in Dam

I just bought property with two ponds on it. The main pond is 1 3/4 acre. The second pond is 1/4 acre and is directly upsteam from the larger dam. I was inspecting the both dams today and noticed that the water from the smaller dam runs into a hole at the water side of the dam and exits at the base on the other side. This pond is basicly a sedement pond an is currently only about 12 inches deep. If the dam did not leak it would be about 3 feet deep. Both dams are about 25 years old and have never had any kind of drain. I juess they were designed to use the spillway.

Is there a way to fill the hole with clay soil and expect it to seal? Would mixing the soil with bentonite help? Will i have to dig from the top down to the hole and then refill? Any thoughts would be helpful

I forgot to mention that i am planning on using the smaller pond to grow forage for the biger pond. I will install a syphon drain this spring and syphon the forage into the bigger pond

??

I doubt that you can just patch it. A hole in the dam is basically a structure problem with a total washout imminent.

Sorry Pilot, I don't know how your thread slipped by unnoticed. You might want to consider contacting Mike Otto to get a consultation on this.

You might be able to fill the hole with bentonite if it doesn't wash thru the hole first. I'm guessing that for a more permanent fix you'd have to dig it out and re-pack it. But, I'm not a dirt guy. I second the suggestion of contacting Mike Otto.

If your problem was seepage, I would say that you stand a good chance of stopping the leak by adding to the dam and making it wider with high clay content soil. I stopped seepage in my small pond dam by adding more and more pipe and dirt until it sealed. Even though I cored the dam, it seeped due to allot of tree roots in the vicinity of the dam.

With what you are describing though, the only way to fix it would be to stop the water flow i.e. pump it out, breach the dam and start over. Or, wait for a drought.

VA

I don't have any advice on repairing your problem...but on a personal account, we had a similar problem with a nutria(spell check)that made a hole in the side of the pond dam on my property. I didn't think much of it until the first flood we had wiped out about a 12 foot section of the dam. Just wanted to mention this in case you were planning to put that off for a while. Good luck.