Looks like a great forum and I'm anxious to hear your suggestions to my problem. I'll try to summarize what I know short and sweet.

My pond is about 15 years old and should be about 1.5 acres. I've owned it for 4 years.

Was built to be 30 feet deep, deeper than designer wanted it to be, he walked away from it since his directions were not being followed.

It is usually 10 to 15 feet low and at this low point, stops or greatly slows in leaking rate.

I was told the builder hit a spring while building it. I know they tried to patch over it but not sure what was done.

I have since spoke with the designer and he has checked the backside of the dam. He thinks the dam is good and didn't find a leak behind it on the dry side. However, there is water that surfaces behind the dam 80 yards or so away. I know there was historically a spring there so I don't know if it's from the pond or just the old spring.

The designer (USDA pond guy) suggested as a fix, to drain it and have 3 6" layers of clay knitted together with a sheepsfoot roller, over the entire bottom of the pond (everywhere that water would be).

I'm finally to a point where I have a little $$ and want to have it fixed. But I'm on a budget. I got one bid at $10,000. I can't spend this much on it so I'm planning to hire someone to work on it by the hour.

I'm planning to have it pumped out then re-inspected to hopefully identify the area that leaks. If it is found, I'd then just hire someone to patch this area. If we can't find the leak, then I guess I'd have him line the bottom as suggested.

Here are my questions:

How inappropriate is it to just have a dozer do the work, without the sheepsfoot to knit the layers together?

Could the current level be at the water table, and the pumping out of the pond be ineffective?

The surrounding soil is clay. How much time would it take to move enough clay and pack it with a D8 dozer, to cover 1-2 acres?

Since there are some unknowns and no guarantees, how big of a gamble is it to forge ahead on this project (i.e. what is the success rate?)