For the purpose of promoting the health, safety, prosperity and general welfare, as well as for the purpose of securing coordinated plans for land use, transportation, public facilities and utilities and public works expenditures in that portion of Sussex County which is not included within the corporate limits of any city or town, unless any territory within such corporate limits is included upon request made by the governing body or authority of any such city or town, and as well as for the purpose of preventing the unnecessary duplication of facilities or utilities, the body to be known as the County Planning and Zoning Commission of Sussex County is created and the area over which this Commission shall have jurisdiction shall be known as the County Planning District.