S.D. Codified Laws § 38-8-3
In making the determination required by § 38-8-4 and in defining the boundaries of a conservation district, the State Conservation Commission shall give due weight and consideration to the topography of the area considered and of the state, the composition of soils therein, the distribution of erosion, the prevailing land-use practices, the desirability and necessity of including within the boundaries the particular lands under consideration, and the benefits such lands may receive from being included within such boundaries, the relation of the proposed area to existing watersheds and agricultural regions to other conservation districts, already organized or proposed for organization under the provisions of this chapter, and such other physical, geographical, and economic factors as are relevant, having due regard to the legislative policy set forth in § 38-7-1.
SDCL 38-8-3