The board of viewers may employ assistants to make a complete survey of the drainage district. The board of viewers shall: enter the land subject to the petition; survey the main drain and any lateral drain; mark on the ground the line of each ditch, drain, or levee; note the course and distance of each ditch so that each ditch can be accurately platted and mapped; run a line of levels for the entire work and secure sufficient data from which accurate profiles and plans can be made for each proposed drain or levee; establish frequent bench marks along the line on permanent objects and record the elevation and provide a full description of the bench marks in the field books, including the location of the bench marks on a map; run other levels to determine the fall from one part of the drainage district to another, if the board of viewers finds it expedient; and if a watercourse, ditch, or channel is being widened, deepened, or straightened, cross–section the watercourse, ditch, or channel to compute the cubic yards of excavation or fill saved by using the watercourse, ditch, or channel. After completing the survey, the board of viewers shall complete a drainage map of the district showing: the location of the ditch and other improvements; the boundary, as closely as may be determined by the records, of the land owned by any individual landowner; and the location of any railroad or public highway and the boundary of any municipality. In addition to the map, the board of viewers shall prepare a profile of each levee, drain, or watercourse showing: the surface of the ground; the bottom or grade of the proposed improvement and the number of cubic yards of excavation or fill in each mile or fraction of a mile; the total yards in the proposed improvement and the number of cubic yards of excavation or fill in each mile or fraction of a mile; the total yards in the proposed improvement and the estimated cost of the improvement; and plans and specifications and the cost of any other necessary work.