S.D. Codified Laws § 46A-1-39
The district may vest in a trustee the right to receive any part of the proceeds of the bonds and any part of the income and revenue pledged and assigned to, or for the benefit of, the holder of bonds issued under this chapter; the right to hold, apply, and dispose of the bonds; and the right to enforce any covenant made to secure or pay or in relation to the bonds. The district may execute and deliver a trust agreement setting forth the powers and duties of and the remedies available to the trustee, limiting the liabilities of the trustee, describing what occurrences constitute events of default, and prescribing the terms and conditions upon which the trustee or the holder of any specified amount or percentage of the bonds may exercise such right and enforce any such covenants and resort to remedies as may be appropriate.
SDCL 46A-1-39