S.D. Codified Laws § 9-16-3
The governing body of any municipality of the first class, after authorization as provided in § 9-16-1 or 9-16-2, may adopt an ordinance establishing a retirement system covering the employees, elective officers, and appointive officers of the municipality. The ordinance shall provide rules and regulations governing the operation of the retirement system; shall prescribe the membership of the retirement system; shall provide for the retirement of members; shall provide for the payment of annuities, pensions, or retirement allowances or may provide for actuarial equivalents thereof in the event of retirement, disability, or death; shall create a Board of Trustees in whom is vested the responsibility for the management of the retirement system; shall provide for the financing of the retirement system by contributions; and shall provide for the investment of the moneys of the retirement system.
SDCL 9-16-3