I met with Stan last week and looked over his site.
The property has good fall to it, downward into a creek. Lots of trees in the watershed.
All the dirt samples were taken from the creek bottom area, where one would expect to find the worst soils. Dirt in the bottom of a creek are typically soils easily moved with water. None of the samples were taken from the top part of the site. Also, samples were taken by auger, from 5 to 8 feet deep.
Here's the recommendations I made.
Next, do due diligence in dam design, to determine how much clay would be needed to build a dam. Watershed covers 387 acres, so there is plenty of water to fill the lake, and keep it full, even if the dam leaks a little bit.
Then, bring in someone who can 'read' the dirt, put them to work with a backhoe, digging holes up top, looking for good clay. I believe there is good clay somewhere on his ranch.
I also suggested he find a forester to evaluate the trees which must be removed to build the lake. There's enough trees there to have value, if a market is nearby.
This is definitely a site which deserves more exploration.

Teach a man to grow fish...
He can teach to catch fish...