S.D. Codified Laws § 8-5-2
At each regular meeting, the board shall perform the duties required of it by law and transact any other business that may legally come before it. The board may adjourn from time to time. The township clerk or the chairman of the board of township supervisors may call special sessions if the interests of the township demand it upon giving three days' notice of such session by mailing a copy of such notice to each of the supervisors at their several post office addresses or by giving such notice to each supervisor by telephone. It shall be the duty of all persons having business to transact with the board to appear before such board at any regular meeting, or file such business with the clerk to be laid before the board by him at its next meeting.
SDCL 8-5-2