S.D. Codified Laws § 46A-5-19
If any contract is made with the United States as provided in this chapter, bonds of the district may be deposited with the United States at ninety percent of their par value, to secure the amount to be paid by the district to the United States under any such contract. The bonds may be held by the United States, and if deemed desirable, or if the appraised value of the land is double the bonded indebtedness, the bonds may be sold by the United States. The net proceeds received from the sale of the bonds shall be applied to the liquidation of the contract indebtedness of the district to the United States. The interest and principal on the bonds shall be provided for by assessment and levy as in the case of other bonds of the district and regularly paid to the United States, to be applied as provided in the contract.
SDCL 46A-5-19