Section 21. Powers and duties of heads of departments. —

Any existing law to the contrary notwithstanding, each head of department of the city government shall be in control of such department, under the direct supervision and control of the Mayor, and shall possess such powers as may be prescribed herein or by ordinance. He shall certify to the correctness of all pay rolls and vouchers of his department covering the payment of money before payment, except as herein otherwise expressly provided. On or before the first day of March of each year, he shall prepare and present to the Mayor for submission to the Board an estimate of the receipts and appropriation necessary for the operation of his department during the ensuing year, and shall submit therewith such information for the purposes of comparison as the Mayor may desire. He shall make to the Mayor as often as required reports covering the operations of his department.

In case of absence or sickness, or inability to act for any other reason, of the head of one of the municipal departments, or in case of temporary vacancy, the officer next in charge of that department shall perform the duties of the head of the department concerned. In case of a temporary vacancy, the officer next in charge performing the duties of the head of such department shall during his incumbency in an acting capacity receive the salary and other emoluments of the latter.