S.D. Codified Laws § 8-10-22
The board of supervisors of any organized township may determine by resolution that interest shall be paid annually on all outstanding registered warrants of such township. When it has been so determined said board shall, at the time and in the manner provided for the levy of taxes, make a separate and special levy of a tax sufficient to pay one year's interest on each township warrant, which according to the computation of the board will be outstanding and unpaid on the anniversary of the date thereof during the next calendar year. Such levy may be made in addition to the maximum levy otherwise allowed by law, and shall be certified by the county auditor, placed on the tax roll, and collected by the county treasurer as other taxes, which funds derived from such levy shall be kept separate and apart from other tax collections and shall be used for the purpose of paying interest on warrants as provided in § 8-10-23.
SDCL 8-10-22