S.D. Codified Laws § 9-42-8
In the event that any improvement covered by such a contract as described in §§ 9-42-6 and 9-42-7 is to be financed in part by special assessments, the city engineer, or the governing body if there be no city engineer, upon the award of such contract, shall make and file for public inspection in the city engineer's office or in the office of the governing body an estimate of the portion of the cost thereof to be paid by the municipality under the terms of said contract and the agreement made with such state or federal agency for the financing thereof, plus any incidental costs necessary to be paid by the first or second class municipality for the completion of the improvement, and such estimate, when approved by the governing body, shall constitute the basis for the special assessments to be levied as now provided by statute. Such estimate shall be subject to revision in the course of or upon the completion of the work, as the facts may appear, and supplemental assessments may be levied upon the basis of any such revised estimate in the manner provided by law.
SDCL 9-42-8