Moving some dirt and building a beauty berm

We have to undo some work we did about a month ago when we did the rough grading. The builder gave us the ok to lose excess dirt to the right of the last retaining wall, however, its where the drain field for the septic system is going and the inspector would not allow it to be installed with 2' of fill on top of it. With that, we are cutting the dirt out and building a beauty berm along the field just up the hill from it.