The work shift for each department shall be prepared by the department head and approved by the City Manager. The work shift approved by the City Manager shall constitute the standard work shift and standard work week for the particular department. The City Manager may change the standard work shift and standard work week from time to time as he may determine to be necessary for the proper operation of the City. [Ord. 1306 § 55, 1968; Code 1970 § 2.42.410.]