S.D. Codified Laws § 46A-18-64

The district directors may enter into contracts or other arrangements with the United States government or any department, with persons, with public and municipal corporations, with the government of this state, with drainage, soil and water conservation, conservancy, sewer, park, sanitary, reclamation, public power, irrigation, watershed, or other improvement districts, in this or other states. The contracts or arrangements may be for cooperation or assistance in constructing, maintaining, using, and operating the works of the districts, the waters thereof, or in minimizing or preventing damage to the properties, works and improvements of the districts from soil erosion, or for making surveys and investigations or reports thereon.