When the governing body of a city adopts a resolution or other declaration as aforesaid, it shall promptly notify the mayor of such adoption. Upon receiving such notice, the mayor shall appoint five persons who shall be taxpayers who have resided in said city for one year prior to such appointment as commissioners of the authority created for said city. When the governing body of a county adopts a resolution or other declaration as aforesaid, said body shall appoint five persons as commissioners of the authority created for said county. Three of the commissioners who are first appointed shall be designated to serve for terms of one, two, and three years, respectively, from the date of their appointment, and two shall be designated to serve for terms of four years from the date of their appointment. Thereafter commissioners shall be appointed as aforesaid for a term of office of four years except that all vacancies shall be filled for the unexpired term. No commissioner of an authority may be an officer or employee of the city or county for which the authority is created. A commissioner shall hold office until his successor has been appointed and has qualified, unless sooner removed according to sections 99.010 to 99.230. A certificate of the appointment or reappointment of any commissioner shall be filed with the clerk and such certificate shall be conclusive evidence of the due and proper appointment of such commissioner. A commissioner shall receive no compensation for his services for the authority, in any capacity, but he shall be entitled to the necessary expenses, including traveling expenses, incurred in the discharge of his duties. The powers of each authority shall be vested in the commissioners thereof in office from time to time. One more than one-half of all commissioners shall constitute a quorum of the authority for the purpose of conducting its business and exercising its powers and for all other purposes. Action may be taken by the authority upon a vote of a majority of a quorum, unless in any case the bylaws of the authority shall require a larger number. The mayor (or in the case of an authority for a county, the governing body of the county) shall designate which of the commissioners shall be the first chairman and he shall serve in the capacity of chairman until the expiration of his term of office as commissioner. When the office of the chairman of the authority thereafter becomes vacant, the authority shall select a chairman from among its commissioners. An authority shall select from among its commissioners a vice chairman, and it may employ a secretary (who shall be executive director), technical experts and such other officers, agents and employees, permanent and temporary, as it may require, and shall determine their qualifications, duties and compensation. For such legal services as it may require, an authority may call upon the chief law officer of the city or the county or may employ its own counsel and legal staff. An authority may delegate to one or more of its agents or employees such powers or duties as it may deem proper.