ML and others :

Like you I don't want persons who have leaks to think fixing them is always easy. However I would try a $200 fix as suggested before I drained my lake and spent thousands {5000 as scsims noted} on trucking in bentonite ,not to mention the fish and the down time while the pond bottom dried, was worked on and refilled.

Hydrostatic pressure applies to ponds as well as oil wells . In wells you often have holes 12in in dia. and 25000 feet deep under much more pressure than any pond. That is a large area {.47 acres} to keep leak free. Like a pond the entire area must be leak free not just one spot. In a well you treat the entire area all the time during drilling . Both deal with keeping water under pressure from penetrating into dirt , rock and sand . In ponds like oil wells bentonite {drilling mud} in solution migrates to the area of lowest pressure {the leak} and bonds with the rock ,dirt and sand to stop water loss.

The leaks as described by the posters sounded like specific areas to me not an overall lack of clay in the soil. In scsims case with a small pond you could treat the whole pond with 40 bags for $500 . The Pomdboss ad for one of the services shows a truck with a mud pumping unit pumping a liquid {looks like bentonite in solution} into a pond. That is just about what was suggested.

I think it is important for fourm members with questions to have as much info and options as they can. They seemed desperate to me { drain my pond/ jump off the dam}. What are their choices? Start over and spend a lot of money on a method that you noted may not work or what? There were no other options suggested so after thinking about it I and others gave them one that has worked and at much lower cost.

The general solution is have your dirt tested and treated if needed before you build . Having gone past that point there is no general solution other than fix it with bentonite or barite either your self or by an expensive service , that is unless you want to start over and maybe at a different location. I hope this clears up my prior posts. ewest