On or before the date specified in said ordinance, it shall be the duty of each of such public corporations, by its legislative or governing body, to elect 1 member of a joint board or commission. The members so elected shall elect 1 additional member, and the board so constituted shall have full control of the operation, extension and improvement of the system except as herein otherwise provided. The members of such board shall be elected annually in the same manner.
MCL 123.334