S.D. Codified Laws § 49-16B-21
The charges, fees, or rentals established by the authority for the use of any facilities acquired, constructed, completed, or equipped in whole or in part with the proceeds of the bonds or instruments issued as provided in this chapter and leased to lessees other than the Department of Transportation shall be sufficient at all times to pay maintenance and operation costs for the facilities (unless under a lease maintenance and operation costs are otherwise provided for), principal of and interest on the bonds and a proportion of the administrative expenses of the authority as provided for by each lease, and such reserves as may be provided in the resolutions of issuance and may provide for conveyance of the facilities to the lessee at the conclusion of the term of the lease.
SDCL 49-16B-21