After such hearing the department shall determine, upon the facts presented at such hearing and upon such other relevant facts and information as may be available, whether there is need in the interest of the public health, safety and welfare for the proposed subdivision and whether the operation of the districts within the proposed boundaries will be administratively practicable and feasible. In making such determination, the department shall give due weight and consideration to the legislative determinations set forth in § 48-9-20 and to the standards provided in §§ 48-9-560 and 48-9-600 for the guidance of the department in making its determinations in connection with the organization of districts. If the department determines that the proposed subdivision is not necessary in the interest of the public health, safety and welfare, or that the operation of the districts within the proposed boundaries would not be administratively practicable or feasible, it shall record such determination and deny the petition. If the department shall determine in favor of the proposed subdivision, it shall record such determination and define the boundary lines between the districts and shall notify the chairman of the governing body of the district to be divided of its determination.