If at all possible, existing contours should be preserved. When the ground elevations are to be altered by more than two feet (2'), the proposed contours shall be depicted on a plan according to the provisions of the Illinois procedures and standards for "Urban Soil Erosion And Sedimentation Control", Association Of Illinois Soil And Water Control Districts, current edition, and shall be approved by the village engineer. (Ord. 92-1855, 12-14-1992)