1. The department may proceed of its own motion to form such district and to authorize the proposed work as though petitions therefor had been filed as provided in sections 15-1911 and 15-1913 or 15-1931. It may negotiate with the federal government, investigate the proposed district, study such plans of and reports on the proposed improvement as it may find to be available and shall prepare a written report thereon describing the proposed district, the proposed work, the fixation of the district boundaries, giving estimates of the cost of the various parts of the work which may be a charge against the state or the property owners in the district and including a determination of enhancements and an apportionment of costs of such a project. Such report shall be filed and notice of such filing and of a hearing thereon given as provided in sections 15-0903, 15-1913 and 15-1931.

2. After the final hearing the department shall determine whether it is to the public interest to form the district and to proceed with the work and, in general terms, what lands will be benefited thereby. These matters shall be embodied in a written order, which shall, if the action is favorable, form the district, authorize entry into agreements with agencies of the federal government and the doing of whatever is needful to carry out the project, all as elsewhere specified in title 19 of this article. Certified copies of the determination and order shall be filed and notice of such filing given. Thereupon such determination may be reviewed as provided by section 15-0905, except that the proceedings for such review must be initiated not later than ten days after such filings; otherwise such determination shall be considered final and conclusive and in due course it shall be recorded. The district shall be held to have been formed on the date of such final order, but such formation shall not be effective until such order shall have been recorded.