Each authority shall be governed by a board of directors consisting of three directors, all of whom shall be persons of good moral character, duly qualified electors of the state and residents of the area of operation of the authority. All powers of an authority shall be exercised by the board or pursuant to its authorization. If the area of operation of an authority shall be wholly within the corporate limits of any municipality, the directors of that authority shall be appointed by the governing body of that municipality. If the area of operation of an authority shall be wholly within a single county, the directors of that authority shall be appointed by the governing body of that county. If the area of operation of an authority shall be larger than any single county, the directors of that authority shall be appointed by the Governor. Whenever the appointment of directors of such an authority is required, the Governor shall notify the respective county governing bodies in writing of the authority and the number of directors to be appointed. The Governor may appoint as a director of the authority any person qualified to serve as such under the provisions of this article; provided, however, that the Governor shall notify the respective county governing bodies, in writing, 20 days prior to the appointment. The terms of the directors shall be staggered, the first term of one director being for two years from and after the date of his appointment, the first term of another director being for four years from and after the date of his appointment, and the first term of the remaining director being for six years from and after the date of his appointment; thereafter, the term of office of each director shall be for six years. Each director shall serve during his term of office, and until his successor is appointed and qualified. Vacancies on the board shall be filled by appointment by the governing body or the Governor having the power to make the appointment for the full term. Appointments to fill vacancies which occur during a regular term shall be for the unexpired term. Directors shall be eligible for reappointment. If the certificate of incorporation shall so provide, each director may be reimbursed by the authority for actual expenses incurred by him in and about the performance of his duties. Any director of an authority may be impeached and removed from office in the same manner and on the same grounds provided by Section 175 of the constitution of Alabama and the general laws of the state for impeachment and removal from office of the officers mentioned in said Section 175.