S.D. Codified Laws § 46A-9-45
Such water user district shall have the right to appropriate the waters of the state in the same manner as other appropriators under the laws of this state; provided, that such district shall not, in the exercise of the powers conferred by this chapter, interfere with, injure, or otherwise damage or affect existing water rights, other than through the purchase of such rights or through condemnation proceedings as provided in this chapter; and provided, further, that no irrigation district, corporation, association, or individual holding a water right for lands located either within or outside the boundaries of a water user district shall be in any way affected by the operations of such district other than by reason of a contract voluntarily entered into by such organization or individual with such district, or by reason of the exercise by such district of the power of eminent domain as provided in this chapter.
SDCL 46A-9-45