My boss asked me to calculate the volume of a pit with a berm around it. He wants it as big as possible within a certain perimeter. The material dug out of the pit will be used to create a berm around the pit, which will increase the pit's depth. All of the material needs to remain within the perimeter, so the cut and fill need to be equal (or as close as reasonably possible). I have the perimeter and the existing grade, but I'm not sure where to start constructing the other surface(s) needed, or what tools will best achieve these ends. Any suggestions are appreciated.