S.D. Codified Laws § 46A-14-43.1

In addition to the procedures provided in § 46A-14-43 for adopting watershed district bylaws, bylaws may be proposed by petition of twenty-five percent of the eligible voters of the district. The proposed bylaws shall be adopted if approved by the board of managers of the watershed district and if at least sixty percent of the votes cast in a special election on the issue are in favor of adopting the proposed bylaws.