If at the time fixed for the hearing of the report, the supervisors or board of commissioners shall find that notice has been given, as required by section 23-312, and further find that the proposed work is of public utility, convenience, welfare or safety, and that the benefits assessed exceed the expenses and damages whatsoever they may be, they shall order that the improvement be made and shall specify therein the nature and extent of the improvement. The report of the engineer as finally adopted by the board shall be designated as the plan for protection and shall be submitted to the Director-State Engineer for his information and approval; Provided, that notice of the hour and day of such submission shall be once published in the newspaper selected by the board for other publication notices, at least five days prior thereto. This plan as approved by the Director-State Engineer shall stand as final.