On a nonconforming lot of record on which only a residential structure exists, and it is not possible to place an accessory structure meeting the required water body, tributary stream or wetland setbacks, the Code Enforcement Officer may issue a permit to place a single accessory structure, with no utilities, for the storage of yard tools and similar equipment. Such accessory structure shall not exceed 80 square feet in area nor eight feet in height, and shall be located as far from the shoreline or tributary stream or other setbacks as practical and shall meet all other applicable standards, including lot coverage and vegetation-clearing limitations. In no case shall the structure be located closer to the shoreline or tributary stream than the principal structure.