A detailed site plan showing: the location, proposed use and height of all buildings; the location of all parking and truck loading areas with access and egress drives thereto; the location of all existing or proposed site improvements, including drains, culverts, retaining walls and fences; a description of the method of sewage disposal and the location of such facilities; the location and size of all signs; the location and proposed development of buffer areas, if required; and the amount of building area proposed for retail sales uses, if any.