Sec. 678. Powers and Duties of the General Manager.

   In addition to the powers described in Section 604, the general manager of the department shall have the power and duty to:

   (a)   enforce all orders, rules and regulations adopted by the board;

   (b)   supervise and manage the design, construction, maintenance and operation of all work or improvements authorized or ordered by the board; and

   (c)   carry out all powers and duties of the department delegated by the board.