No locality or authority shall construct, provide or operate outside its boundaries any water supply impoundment system without first obtaining the consent of the governing body of the locality in which such system is to be located; however, no consent shall be required for the operation of any such water supply impoundment system in existence on July 1, 1976, or in the process of construction or for which the site has been purchased or for the orderly expansion of such water supply system. In any case in which the approval by such governing body is withheld, the party seeking such approval may petition for the convening of a special court, pursuant to §§ 15.2-2135 through 15.2-2141.