For any new proposed development subject to flooding which includes, but is not limited to, those lots along any significant watercourse, whether or not the stream or water course is enclosed with a pipe or culvert; the applicant shall make a determination of the crest elevation of the flood expected to be equaled or exceeded that has a one percent (1%) chance of annual occurrence in accordance with generally accepted engineering practice, which is to be submitted with the seal and signature of a Professional Engineer to Cary. Any new construction of, or substantial improvements (see Chapter 12, Definitions) to, any residential or non-residential structure shall comply with Section 14.7.3(B).