S.D. Codified Laws § 38-8-39
The governing body of a district shall consist of a board of supervisors.
Each conservation district shall have a board of supervisors consisting of five members, each of whom shall be elected on a nonpartisan ballot at a general election and whose term of office shall be four years commencing on the first of January following election. Supervisors shall be registered voters within the district, to be elected at large.
The board of supervisors may, at its discretion, choose to elect its supervisors in precincts that contain as near as possible an equal number of residents, as determined by the last preceding federal decennial census.
Before any general election, the board of supervisors of an organized conservation district shall give notice of any district offices for which nominations may be filed. The notice shall be published at least once each week for two consecutive weeks in the official newspaper or newspapers of any counties within the territory of the district. The last publication may not be less than ten nor more than fifteen days before the deadline for filing nominating petitions. The Division of Resource Conservation and Forestry shall provide the required notice before a referendum regarding establishment of a new district.
Supervisors shall be nominated by a petition signed by fifteen or more voters in the district for which the candidate seeks election.
The petition shall be verified by the circulator and be accompanied by the declaration of the candidate in a form substantially conforming to nominating petitions prescribed under the primary election laws of this state governing nominating petitions for nonpolitical candidates. The petition shall be filed on or before July first of the year in which the general election is to be held, with the county auditor of the county, or where more than one county is within the territorial limits of the district, with the secretary of state. The auditor shall prepare ballots substantially in the form of the nonpolitical ballot and give notice thereof as provided by the general election laws of this state. The supervisors shall be elected by plurality. The election shall be conducted, canvassed, recounted, and contested as elections under the general laws of this state, except as otherwise provided in this chapter, and unless the general laws are inapplicable. If the details concerning the conduct, canvassing, recounting or contest of the election are not set forth within this chapter, and the general election laws are not applicable, then the commission shall promulgate rules pursuant to chapter 1-26 to make possible the submission to an election any matter which by the terms of this chapter may be submitted to a vote of the voters of any proposed or established district.
SDCL 38-8-39