Good morning all,
I wanted to get opinions on a new pond project at our little farm. I’m thinking of digging a 100x75 fish pond. The goal is two fold…I need about 900 yards of fill dirt to level a low spot and I love catfish fillets. A pond is a win win!
Here’s the specifics:
Good red clay at 6’6” deep sandy loam above.
Ground Elevation fall of 4ft. Across the 75ft width. Thinking of making the shallow end of the pond on the high side and building a dam on the low side. Building dam with mostly loam and then lining with 1ft of clay. Then lining the remainder of the pond with 1ft of clay.
Any holes in my plan?

FP,

What is the planned max depth of the pond?

The hydrostatic pressure (water depth) is one factor that controls the required thickness of the clay liner.

Also, the dam has to have some lateral strength to resist the pressure of the water in the pond. Imagine a dam built with dry sand and then lined with a foot of clay. It would actually "seal" and hold water, but the pressure of the water would make the sand start bulging in some spot and then the clay seal would crack and then the dam would give way.

Here is an old thread that discusses some of the basics.

Pond Keyway

Good luck on your pond! Any project that can kill two birds with one stone is a good project.