I will post some photos here soon, but here is what I have.

Bottom area near a stream we dug down 9ft to make a pond and take out clay to raise the grade elsewhere for an outbuilding pad. We dug down about 4-5 feet and it started to get wet to the point where the tractor had a problem pulling the scraper (being used to dig the pond with). First they thought it was "spring", so the idea was to dig a deep hole in an attempt to pump the water out. That failed and we ended up using a trachoe to dig the pond out.

I pumped the pond out last summer in hopes of finishing the work and then build up a dam 8ft higher than the existing spillway. I noticed at that point that the lower 3-4 feet was perpetually wet and would never seem to dry out all the way around the pond. The bottom of the pond was a messy muck where I sunk down to my knees when I entered it. I would have to pump the bottom every couple of days to keep it the water down because it would slowly start to fill again.

So my question...

If I dam up the outlet 8ft more to better match the surrounding area, what is the chance of this being successful?

Would filling the bottom 3-4 feet with clay and packing it have any better chance of success?

Would a liner make more sense?