(1) to permit local governmental units to make the most efficient use of their powers by enabling them to cooperate with other localities on a basis of mutual advantage and thereby to provide services and facilities in a manner and under forms of governmental organization that will accord best with geographic, economic, population and other factors influencing the needs and development of local communities; and

(2) to provide the benefit of economy of scale, economic development, and utilization of natural resources for the overall promotion of the general welfare of the state.