1. The department may proceed to make such survey of the district as may be found to be necessary. It shall prepare maps of such district showing natural and artificial features as may be needed, the boundaries of the district, the boundaries and area of each parcel of land in the district together with the name of the owner thereof so far as the same readily may be ascertained. When a parcel is intersected by a county, town, village or city line, the area in each such political subdivision shall be given. Each parcel of land or each subdivision thereof shall be designated by a number. In the course of the proceeding further subdivision of parcels may be made if necessary or convenient.
2. The department may then determine the enhancement accruing to each such parcel due to drainage as provided in sections 15-1919 and 15-1921, prepare designs and estimates for drainage works as provided in section 15-1923, prepare a general apportionment of cost as provided in section 15-1925 and 15-1927, and fix the final boundaries of the district as provided in section 15-1927.