In the event that the city council shall determine to follow the procedure provided in this chapter with respect to the organization of the district, the report shall omit the diagram and proposed assessment referred to in subdivisions (c) and (d) of Section 18041, but the plans and specifications referred to in subdivision (a) of Section 18041 shall include or be accompanied by a map or plat of the district, showing the lands, including all zones thereof, if any, to be benefited by the proposed improvement and to be assessed to pay the expenses thereof.