S.D. Codified Laws § 9-9-26
If a municipality is governed by a board consisting of three commissioners, the mayor shall exercise all the powers and perform all the duties provided by the laws of this state or the ordinances of the municipality not in conflict with state law. The mayor shall be the chief executive officer of the municipality, shall preside at all meetings of the board, and has general supervision over all departments and officers. In the absence or inability of a commissioner, the mayor shall temporarily take charge of the department of the commissioner. The mayor shall see that all the laws of the municipality are enforced and that the conditions of the grant of any franchise or privilege are faithfully complied with and performed. The mayor shall grant all licenses or permits, except as required by ordinance to be granted by the board or by some other department or officer.
SDCL 9-9-26