Prior to the issuance of a building permit for any single-family dwelling, the applicant for the permit shall submit to the Building Inspector for his or her approval two copies of a detailed site plan at a scale of one inch equals 30 feet, sheet size 8 1/2 inches by 14 inches, prepared by a licensed professional engineer or licensed land surveyor, showing the existing and proposed contour lines at two-foot intervals of the plot on which the dwelling is to be constructed, final elevations in accordance with an assumed datum proposed for the corners of the plot, corner and floor levels of the structure to be erected thereon. A bench mark shall be shown on the plan. In addition, the detailed site plan shall show swales, brooks, streams, springs, retaining walls, terraces, sidewalks, slopes, major rock formations, existing easements, building line setback and elevation at the curb, where existing, and, if no curb, elevation at existing opposite lot corners and center line of driveway where building is to be located, and all provisions for the proper drainage thereof shall be shown on the plan. No site plan is required to show an area of land in excess of one acre nor to show any area of land more than 100 feet from any exterior wall of any main building shown on the site plan, if the applicant shall own more than one acre.