Pond Boss Forums POND CONSTRUCTION Renovating a Pond or Lake? Leaking Dike

Hi,

I've built about ten 1 acre ponds. I always had good clay and cored the dike and compacted the clay. None of them leak. I bought a property with a small (1/8 acre) existing pond. It is leaking slowly through the dike. I have been digging a 2 foot trench down the middle of the dike looking for the leak. The soil is terrible. Rocks and clay. LOTS of rocks. I can't find good clay anywhere without some rocks.

I wonder if I cored down as far as I can go and added lifts of bentonite and my poor soil?

Far easier to apply SeekLeak polymer to the dam heel - unit of SeekLeak treats 1000-3000 SF depending on leak rate. Following application seepage should be diminished. Feel free to reach out anytime - I help folks nationwide with pond construction, rehab, and leak abatement and my time is free to my Pond Boss family.

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If there are sections of the dam with sufficient patches of rocks such that they are in point-to-point contact, then that is a leak pathway that is VERY difficult to seal.

I have had one "crazy" idea for a situation on my property similar to what you are describing. Hopefully, the experts on the forum can evaluate its chances of success.

Once you have excavated your long trench, you will have an exposure in your dam that is exactly the same shape as the way vendors sell pond liners! A piece of liner that is 10' wide and 80' long is not that expensive. I would consider hanging a pond liner on the downstream wall of your excavation. Bring the top edge of the liner up above the normal water elevation and then pin it in place.

I would then find the best clay anywhere on the property, or even consider trucking in some clay. You wouldn't need that much clay. You just need a u-shaped sealed area of clay to seal the edges of your pond liner. Pack two feet of clay along the bottom edge. Also seal the two vertical edges with good clay as you backfill your trench.

The nature of the rest of the backfill material should not matter much, since the pond liner will be doing most of the sealing work. (Do make sure you exclude the sharp-edged rocks so you do not puncture your liner.)

I have no clue if this will work. It is just an idea in my head, NOT a proven pond practice.

Good luck getting your pond sealed.

I don't think you would need the liner. A two foot core compacted correctly with good clay should fix it.

I definitely agree.

I didn't know if the liner might be cheaper than getting enough good clay to location to do it the correct "old school" way.

I don't know. I have never had to buy clay.

Are you a pond builder? Have you done any other improvements on your new property and excavated some better "core trench" material?

If you own (or commonly rent) the heavy equipment, you could move some good material on your own property a short distance pretty cheaply.

OTOH, a dump truck load of clay from a nearby new housing development where they are digging out basements, could probably be diverted to your property at an affordable price.

[I am a geologist, NOT a pond builder. However, I hate the rocks in your leaking dam. No amount of compaction can seal imbricated rocks.]

Ooooh! I got yo look up a new word, Imbricated: