Pond Boss Forums POND CONSTRUCTION Soil questions How steep can I make a clay bank?

A customer has clay that he can make pots from. He had the contractor dig the pond deeper and he did it with water in the pond. Vertical walls in the pond down to 20; deep. They lasted for about 2-3 years, then they started to slough off and slide into the pond. His pond now, 5-6 years later went from 28' deep to 15' deep, and his banks caved into the pond a good 5'-8' back from the original pond banks.