Hi Jason,

A berm to me has sloped sides so the cross section would look like the diagram in our response to peter. If this is true for your berm then the answer to your question is contained in our response to John.

If your berm doesn't have sloped sides then the area of the cross section is width (20 feet) times the height (12 feet) and the volume is the width times the height times the length. This will give the volume in cubic feet. To determine the volume in other dimensions, for example cubic yards, ask Google. If the volume is $V$ cubic feet then type what is V cubic feet in cubic yards into the Google search window. I'm a Mac user so I would ask Siri.

Penny