85-7-202. Application of part. This part shall apply only when 20 or more owners of land with water rights appurtenant thereto are being served by one stream and its branches or from one source of water supply and in which the rights to the use of water shall have been determined by decree of a court of competent jurisdiction and at least 2,000 acres of land, contiguous in location or of reasonably compact area, are being served by the single stream or source.