S.D. Codified Laws § 31-13-27
Contracts pursuant to § 31-13-26 are authorized without advertising for bids if the total cost in a winter's season will not exceed thirty-five hundred dollars. If the cost will be less than thirty-five hundred dollars, the township supervisors may make contracts with any person, firm, or corporation, including any county, for the removal of snow on its roads, or repair of such roads damaged from or caused by melting snow, either at an hourly or day rate. If it is anticipated that the cost in any one winter would exceed that sum, the snow removal or road repair shall be done by bids as provided by law. In case of such road damage, the work may be undertaken on bids as above specified, or upon an hourly or day rate for such work.
SDCL 31-13-27