To discourage the proliferation of wireless communications towers, shared use of tower structures is both permitted and encouraged. If feasible, wireless telecommunications service facilities shall be located on existing structures, including but not limited to buildings, water towers, existing telecommunications facilities, utility poles and towers and related facilities, provided that such installation preserves the character and integrity of those structures. All site plan applications for new wireless telecommunications towers must include documentation regarding the availability of any existing or approved, but unbuilt, communications towers within the transmission area that may meet the needs of the applicant. Evidence of the written contract with all wireless service providers who supply service within one mile of the proposed tower must be provided. The applicant should inquire about potential collocation opportunities at all technically feasible locations. The contracted providers shall be requested to respond in writing to the inquiry within 30 days. The applicant's letter, as well as the responses that are received, shall be presented to the Planning Board as part of the site plan application package.