S.D. Codified Laws § 1-16B-62
The bonds may be secured by a trust indenture by and between the authority and a corporate trustee which may be any bank having the power of a trust company or any trust company within or without the state. The trust indenture may contain any provisions for protecting and enforcing the rights and remedies of the bondholders as may be reasonable and proper and not in violation of law, including covenants setting forth the duties of the authority in relation to the exercise of the authority's powers and the custody, safekeeping, and application of all money. The authority may provide by the trust indenture for the payment of the proceeds of the bonds and the revenue to the trustee under the trust indenture or other depository, and for the method of disbursement thereof, with any safeguards and restrictions as the authority may determine. All expenses incurred in carrying out the trust indenture may be treated as a part of the operating expenses of the authority.
SDCL 1-16B-62