Where any artesian conservancy district has heretofore been formed, and due to the extension of the original boundaries of the artesian basin by order of the state engineer, the boundaries of the artesian conservancy district no longer include all lands overlying such artesian basin and the board of directors of such district shall determine by resolution that it is desirable that such lands, as are irrigated and within the boundaries of the said artesian basin as set by order of the state engineer effective January 31, 1950, shall be included in and subject to the district, such conservancy district may file a petition in the district court of the county wherein said district was originally formed in the same proceeding, praying that the decree providing for the formation of said district be amended so as to include such lands; provided, however, the petition shall be accompanied by a certificate of the state engineer, describing the designated boundaries of the said artesian basin.