If you own a farm and have always dreamed of having a pond so you could fish, swim, or boat whenever you liked without leaving the comfort of your own land then you have probably contemplated building your own pond. Before you finish your farm pond you will need to seal it in order to keep water simply from draining into the soil as your pond fills up. There are a few ways to seal a farm pond, and none of them are difficult, although some can be costly.
Use the bulldozer to smooth out the pond's bottom surface upon the completion of the digging of the pond itself. Drive over the surface with the bulldozer several times to pack the soil down.
Decide if you will use clay, bentonite, or organic matter to seal your pond. If you have livestock, organic matter is the cheapest and easiest way to seal the pond.
Fence livestock such as goats, cows or pigs into your pond using the fencing materials and allow them to live there for several weeks. Their feces will get worked into the soil and will effectively seal the soil from leaks.
Use clay to seal your pond if you do not have access to livestock. The clay can be shipped in by truck and dumped into the pond. Then use the bulldozer to smooth out a fairly thin (1-3 feet thick) layer of clay along the entire bottom surface of the pond.
Seal your pond with Bentonite if you do not have livestock or clay available. Spread the Bentonite all over the soil and use the bulldozer to work it into the soil. Again, smooth out the surface and allow to dry before filling with water.