S.D. Codified Laws § 46A-4-14.1
In any existing or proposed irrigation district containing Indian tribal or trust lands, the Board of Water and Natural Resources shall establish one division to represent all such tribal and trust lands upon application of any holder of Indian trust land, including an Indian tribe. The appropriate tribe shall appoint the director for that division and shall fill any vacancy in that office. If a holder of trust lands who has applied for inclusion within the district does not wish to be represented by the tribal representative, the Board of Water and Natural Resources shall include the land in one of the other divisions of the district. The other provisions of this chapter pertaining to the nomination of director candidates, the election of directors, and the filling of vacant director positions do not apply to the division representing tribal and trust lands or to any director or candidate for director for the division representing tribal or trust lands.
SDCL 46A-4-14.1