S.D. Codified Laws § 46A-6-5
Any organized irrigation district may whenever it appears necessary, proper, or beneficial to drain any of the land within the district, either for the benefit of the land actually requiring drainage or for the protection of other lands within the district, whether the irrigation works have been actually acquired or constructed or not, cause drainage canals and works to be constructed. For these purposes, the district may levy special assessments or otherwise provide funds necessary to properly drain the lands, enter upon lands for the purpose of making surveys, exercise the right of eminent domain, and contract for the construction of necessary ditches. The district may extend the drainage ditches outside of the limits of the district for the purpose of conducting the drainage water to other lands upon which the water may be lawfully used or to return the water to some natural watercourse. The powers granted in this section include the power to enter into a contract with the United States of America to carry out and effectuate all proper drainage of the district or any part of the district; and any such contract shall be treated, to all intents and purposes, as if made under the provisions of this chapter.
SDCL 46A-6-5