In selecting or changing to a form of government based on any of the four plans set forth in section two, article three of this chapter, a city may by charter provision withdraw from the governing body and administrative authority of the city the municipal powers and authority and duties pertaining to a city gas system, city electric system, any municipal public works in accordance with the provisions of article sixteen of this chapter, a city waterworks system in accordance with the provisions of article nineteen of this chapter, a city sewage treatment and disposal works, or a combined city waterworks and sewerage system in accordance with the provisions of article twenty of this chapter, or any combination of the foregoing, and confer such powers and authority and duties upon one or more independent boards created by charter provision, whose members shall be elected by the qualified voters of the city, or appointed, in the manner provided by charter provision. Unless and until abolished by other charter provision, such board or boards so created shall have complete and exclusive jurisdiction of the exercise and discharge of the municipal powers and authority and duties so conferred upon it or them, independent of control by the governing body and administrative authority of the city. Such boards shall have the powers and authority and perform the duties conferred and required by general law.

The provisions of this section shall be construed as conferring additional powers and authority upon cities, and shall not be construed as affecting any powers and authority heretofore conferred upon any city by general, special or local law or by special legislative charter, or parts thereof; however, whenever a board is established by charter provision in accordance with the provisions of this section in connection with a municipal public works, a city waterworks system, or combined city waterworks and sewerage system, as aforesaid, such board shall act in lieu of the governing body of the city with respect thereto, and the provisions of said articles sixteen, nineteen and twenty of this chapter authorizing the establishment of a board with respect to any such public works, waterworks system or combined waterworks and sewerage system shall not be applicable.