The assessor shall make, or cause to be made, a list showing the apportionment or distribution of assessments with a description of each unit or tract of land assessed in the district and the name of the record owner of each unit or tract. Alternatively, the assessor may prepare a map on a convenient scale showing each unit or tract of land with the amount per acre [.40 hectare] apportioned to the unit or tract. Where practicable, the units of land must consist of governmental subdivisions of forty acres [16.19 hectares] or more. If all lands on the statement or map are assessed at the same amount or rate per acre [.40 hectare], a general statement to that effect is sufficient. A copy of the list or map must be filed in the office of the county auditor of each county in which the district is situated, and another copy must be filed in the department of water resources. One copy must remain in the office of the board for public inspection.