Does anyone have any suggestions on how to stop a slow seeping leak on our 2 acre pond? We had it cleaned while it was dry last year. There were a couple of trees growing on the top, but had them dozed and re-worked the dam, but it is still leaking slowly. What will plug it without killing fish?

I just noticed an earlier post on this topic. Good answers and suggestions. Does anyone know if bentonite will harm the fish?

Doesn't bentonite have to be applied before filling pond? Have you consulted with your county agent or soil conservation service?

Bentonite will do it and no, I don't believe it will harm the fish. Used it on my pond dam years ago

Do you know where the leak is? Also what caused it?

Around here either crawfish or apple snails dig through levees, especially where there may be dead tree roots.

My ponds and lakes are all levee type (above grade), so I dig down with a back hoe in the middle of the levee where its leaking, all the way to below ground level and then pour in a mix of bentonite, Portland cement and dug up clay back into the hole and let it set up. Won't ever leak there again.

If I only have an idea of where the hole is, I can just put a bunch of bentonite on top of the spot, or use organic material such as old hay, cow manure or compost on top of the area to plug the holes.

IF a bunch of catfish in the pond, they can be fed over the leak and their droppings may seal it up.

Betonite can be applied before or after the pond is full. It is preferred to be done before, creates a better seal in marginal soils or where the clay didn't seal properly with surrounding soils. The plugs do work from what i have been told, never used them myself.

2 other products that can be used on a pond that is full is ESS13 and Soilfloc. ESS13 is not fish friendly, where as Soilfloc is fish friendly. If you know where the leak is you can concentrate your application.

LOL...thought I was the only one that does this. It absolutely works...100% for me.

Having said that, however, it only works if the leak is through the dam. Some leaks are through the bottom. Springs are especially vulnerable to reversed hydrostatic pressure and can leak with the water often showing up below the dam as area that stays wet. For these, packing the area in at least two feet of good clay will do the trick...but much more of a problem if the pond is full. Bentonite can work...but you have to get sufficient material over the exact precise area....very difficult to do with the pond full.

It took a few tries to figure out.....one spot on the thirty acre reservoir always leaked. I used only bentonite several times and it worked, but would start up again. Crawfish (and/or apple snails) had dug through again. The last time I fixed it I added the Portland cement to the mix. That was over 12 years ago, no more leak.

Great answers and info.

The leak is right in the deepest side at about 1/3 depth from full down. There was a big willow tree on top there before, but it was dozed last year when we re-worked it. I'm guessing the root system has still compromised the integrity of the dam. The leak is a lot slower than before, but still seeping a good bit.

Thanks for the responses.

Drain and put in a liner if all else fails

hmmm.....it would work, but.....cost roughly $50K plus installation for two acres using either epdm or pvc.

I had a guy call me to scuba dive and find his low spot and mark it with markers and he had a company come in and shoot bentonite in it. I haven't heard the end result but he said they just need to know where to shoot it.