New 1 acre impound pond leaking (more than a seep) at the toe along approx 90' section. Has wide and deep key, did 2' foot lifts. Compacted slopes and lifts with commercial large CAT vibratory compactor. We have a 15' dug deep section, but most of pond base is 10', have small island with "underwater" bridge. Lots, many, a lot of springs on the upside bank, the impound is approx 10'. Been through 2 thaw cycles.

Wondering if I should try bentonite sprinkled/dumped on the surface, especially around the island and underwater bridge as those are virgin ground. We used a bentonite mat in the deep section only as that base was boney.

Would appreciate ideas on how to solve and if you folks have good luck with the "sprinkle" method of Bentonite. thank you

Hello and welcome to the forum. I help folks with construction, rehab, and leak abatement nationwide and as a volunteer here my time is always free. Holler anytime happy to jump on a call and help review your options moving forward - might be a good candidate for water born polymer seal of which I’ve done over 1000 to date. Will help you avoid all the mistakes I’ve made during pond construction. Again welcome to the forum great to have a NYer around!

Tj@hudlandmgmt.com

I have not heard of the sprinkle method of applying bentonite to be more than a temporary fix.

In my experience it’s not even a temporary fix.

Been planning for some time to put a pond in would like to see follow up on any progress. Also like to hear more about this polymer seal. Area I'm looking at is shale. Would like to avoid problem before hand, but like to learn regardless.

Shale might be tough.

If it has natural fractures or joints, then those are typically very difficult to seal.

Are there any ponds in the immediate area surrounding your property? That would be a good sign.

Also, do you have good clay on the property? If you do encounter permeable bedrock in your pond basin, it is possible to seal it off with a clay blanket installed in a few compacted lifts.

Good luck on your project!

(If you post more questions or plans for your pond, then you may want to start a new thread.)