S.D. Codified Laws § 9-21-15
No expenditure for any improvement, replacement, repair or service shall exceed in any one year the amount provided therefor in the annual appropriation ordinance of a municipality, except that the governing body may expend the proceeds of any bond issue authorized by the voters of the municipality, or in case of emergency, by a unanimous vote, may by resolution order any improvement, replacement, repair or lawful service the necessity of which is caused by any casualty, accident, circumstances or event happening after such annual appropriation ordinance is made which could not have reasonably been anticipated at the time of making the annual appropriation ordinance. The governing body may order the mayor or president to borrow in the name of the municipal corporation, with the attest of the auditor or clerk, a sufficient amount to provide for the necessary expense to be incurred in making any improvement, replacement or repair and in furnishing such service the necessity of which has so arisen, for a period not exceeding the close of the next fiscal year, which sum and interest shall be added to the amount authorized to be raised by the next general tax levy.
SDCL 9-21-15