Sec. 21. (a) The surveyor's preliminary report must include the following:
(1) Plans and specifications.
(2) Cost estimates.
(3) Damages.
(4) Assessments.
(5) Other information that is considered necessary and proper.
(b) The department may on request of the surveyor prepare the plans and specifications.
(c) The surveyor in preparing plans and specifications may, upon the recommendation of the department, vary from the general plan described in the petition if necessary to carry out the purpose of the petition, subject to final approval by the court.