The board of supervisors of any drainage district organized under the provisions of this chapter may, as soon as they have organized as provided under § 49-19-580 or at any time before the adoption of the Plan of Reclamation, levy a uniform assessment, hereinafter called a tax, of not exceeding fifty cents per acre upon each acre of land within such drainage district, as defined in the petition and decree incorporating the district, to be used for the purpose of paying expenses incurred or to be incurred in organizing the district, making surveys of the district and assessing benefits and damages and to pay other expenses necessarily incurred as may be estimated by the board and chief engineer before the funds to pay the total cost of the works and improvements of the district are available. In case the boundary lines of the district be extended under the provisions of §§ 49-19-2510 to 49-19-2550 so as to include lands not covered by the petition the same uniform assessment shall be made on such other lands as soon as they shall have been annexed and included in the district.