Within thirty days after organizing, the board of supervisors shall appoint a competent civil and drainage engineer as chief engineer, who may be an individual, copartnership, or corporation. The chief engineer may, by and with the consent of the board of supervisors, consult any eminent engineer or engineers and obtain his or their opinion and advice concerning the reclamation of the lands in the district. He shall have authority to engage such assistants as may be needed. He shall make all necessary surveys of the lands within the boundary lines of such district, as described by the petition, and of all lands adjacent thereto that may or will be improved or reclaimed in part or in whole by any system of drainage or levees that may be outlined and adopted, and such engineer shall make a report in writing to the board of supervisors with maps and profiles of such surveys, which report shall present a plan for draining, leveeing and reclaiming the lands and property described in the petition or adjacent thereto from overflow or damage by water. Such maps and profiles shall also indicate as far as necessary the physical characteristics of the lands and location of any public roads, railroads, other public utilities, and other rights- of-way, roadways, and other property and improvements located on such lands. The chief engineer shall make a report in writing to the board of supervisors, showing the progress that has been made at such times as the board may require. When the final report of the chief engineer is submitted the board of supervisors shall have authority to employ a reputable consulting engineer or engineers to pass on the adequacy of the proposed improvements as covered in the chief engineer's report and plans. When the board is satisfied of the adequacy of the plans it shall adopt the report and plans and thereafter such adopted report shall be the plan for draining, leveeing or reclaiming such lands and other property from overflow or damage by water, and it shall after such adoption be known and designated as "the plan for reclamation," which plan shall be filed with the secretary of the board of supervisors and by him copied into the records of the district.