After such hearing, if the department shall determine, upon the facts presented at such hearing and upon such other relevant facts and information as may be available, that there is need, in the interest of the public health, safety and welfare, for a soil and water conservation district to function in the territory considered at the hearing, it shall make and record such determination and shall define, by metes and bounds or by legal subdivisions, the boundaries of such district. In making such determination and in defining such boundaries the department 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 and to other soil and water 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 determinations set forth in § 48-9-20. The territory to be included within such boundaries need not be contiguous.