The commissioners herein provided for and their successors in office, shall from the time of their election and qualifications aforesaid, have the power, and it shall be their duty, to manage and conduct the business affairs of the district, making and executing all necessary contracts, appoint such agents and employees as may be required, and prescribe their duties, and perform any and all acts which may be necessary, proper or requisite to carry into effect their duties as commissioners, and all such other acts as may be provided in this chapter or in any other act.