I have dug a pond 330ft.by150ft and 25ft deep. i hit the water table so what do i do now. cover the water back up and clay the bottom? the soil is heavy rock and gravel with alittle clay. all the water runs out when its full in the spring. it takes about 2 mo. to go complete dry.how much clay on the bottom? my contractor says 4 inches.with3 inches on the sides.liners seem really expensive,about 30,000 dollars. Any suggestions regarding how I should/can seal my pond? Thanks. Budman.