Said commissioners shall proceed to assess the land within the district and shall inscribe in a book the description of each tract of land, the benefit to accrue to each tract by reason of such improvement, and shall enter such assessments of benefits opposite the description, together with an estimate of what the landowner will probably have to pay on such assessment for the first year. The assessment shall embrace not merely the land, but all railroad and other improvements on lands which will be benefited by the drainage system. In preparing the description of the lands so assessed, the commissioners may use either (1) the descriptions of lands and subdivisions thereof as shown on the official United States Government surveys and plats of lands within the district; (2) the descriptions of lands and subdivisions thereof as shown upon any plat of lands within the district and recorded upon the land records of the county in which said lands are located; (3) any metes and bounds descriptions found in the latest filed conveyance of said lands and of record in the records of deeds of the county in which said lands are located, and in such case it shall be sufficient to describe said lands by stating the number of acres and the general location of the land within the section, together with the book and page numbers of said conveyance. They shall place opposite each tract of land the name of the supposed owner, as shown by the last county land assessment roll; but a mistake in the name shall not vitiate the assessment. If any landowner or private corporation or any other drainage district has dug ditches or made drainage work that can be profitably used as a part of the general proposed system, the value of such ditches or drainage work to the district shall be assessed by said commissioners and shall appear upon the assessment and be paid for by the district, either in cash or by reduction of assessment. The commissioners shall also assess and place upon said roll or book of assessment, opposite each tract of land, all damages that will accrue to any landowner by reason of the proposed improvement, including all injury to lands taken or damaged; and when said commissioners return no assessment of damages as to any tract of land, it shall be deemed a finding by them that no damages will be sustained. If the commissioners, at any time either before or after the organization of the district, find that other land not embraced within the boundaries of the district will be benefited by the proposed improvement or improvements already made, they shall assess the estimated benefit to such lands and shall specially report to the chancery court, or chancellor in vacation, the assessments which they have made on land beyond the boundaries of the district, as already established. It shall thereupon be the duty of the clerk of the chancery court to give notice by two (2) weekly insertions in a newspaper published in the county where such lands lie describing the additional lands which have been assessed; and the owners of real property so assessed shall be allowed not less than ten (10) days after the last publication of such notice in which to file with the clerk of the chancery court their protest against being so assessed, or included within the district. The chancery court, or chancellor in vacation, shall, at its next succeeding session after the time for filing of such protest shall have expired, investigate the question whether the lands beyond the boundaries of the district so assessed by the commissioners will in fact be benefited by the making of the improvement, and from its finding in that regard, either the property owner or the commissioners of the district may, within twenty (20) days appeal to the supreme court. If the finding is in favor of the commissioners, the limits of the district shall be extended so as to embrace any lands that may be benefited by the making of the improvement. When their assessment is completed, the commissioners shall subscribe such assessment and deposit it with the clerk of the chancery court where it shall be kept and preserved as a public record; provided that, for the purpose of providing funds with which to clean out, restore, repair and rehabilitate the whole or any part of the drainage system of such district or for the purpose of cooperating with the United States or any agency thereof in such works, there may be imposed a uniform assessment on each acre of unsubdivided land lying within the district, and a uniform assessment by lot on subdivided land lying within the district, and the records required in this chapter shall show the amount of the assessment in lieu of the amount of benefits to accrue to each tract. Taxes levied hereunder are hereby declared to be taxes for maintenance purposes and shall not diminish in any manner the amount of assessed benefits in any such district which is otherwise available for the payment of any outstanding bonds of such district.

The assessments provided for in this section may be made even though evidences of indebtedness have been issued or validated or both prior thereto, but the lien of the holders of any such indebtedness shall not be impaired thereby.