The board shall exercise general supervision over the harbor and may adopt general rules and regulations for the government thereof, which in its judgment will best promote the interests thereof, if these rules and regulations do not conflict with the right of any city to exercise its police powers, or with the right of the city to license and regulate business enterprises within its corporate limits. If any business or enterprise is located adjacent to or affects the use and enjoyment of the waters of the harbor, the approval of the board of supervisors shall be necessary to the licensing and regulation thereof.