1. In the event that any agency of the government of the United States shall be willing to perform, direct or finance any work for the improvement of a river, as specified in title 23 of this article, in such manner that the greater part of the cost of such work shall be paid by such government, the department shall have power to form a river improvement district covering the areas to be benefited by such work by following the procedure set forth in this section, in lieu of the procedure specified in the preceding sections of title 23 of this article.

2. The department may proceed of its own motion to form such district and to authorize the proposed work as though a petition therefor had been filed as provided in section 15-2303. It may negotiate with the federal government, investigate the proposed district and prepare a written report thereon, describing the proposed district and the proposed works, and giving estimates of the cost of the various parts of the work which may be a charge against the proposed district. Such report shall be filed and notice of such filing and of a hearing thereon given as provided in section 15-2303, except that the period of notice provided for in section 15-2303 shall be halved. After the final hearing the department shall determine whether it is in the public interest to form the district and to proceed with the work and in general terms, what public corporations and lands will be benefited thereby. These matters shall be embodied in a written order, which shall, if the action is favorable, contain orders to make surveys, assessments, enter into agreements with agencies of the federal government, acquire lands and rights in lands and all other matters which may be needful for the carrying out of the proposed project. Such written order shall state whether it is planned to issue obligations pursuant to the Local Finance Law. Certified copies of the determination and order shall be filed and notice of such filing given. Such determination and order may be reviewed pursuant to section 15-0905, but application for review must be made within ten days after such filing. If no review is had, the department shall cause the same to 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, as made or as modified on review, shall have been recorded.

3. As soon as the formation of the district becomes effective, the department shall have full power to enter into agreements with the proper officials of the federal government or of other agencies of the state, to acquire or to appropriate lands and rights in lands, including sites for camps and appurtenant facilities, access roads, borrow pits, quarries, spoil banks and all necessary and proper matters, to incur contractual obligations, to employ the necessary personnel and generally to do whatever is necessary to carry out the proposed project or projects.

4. After such district is formed and the original federal project authorized, major changes in such project, additional federal projects, changes in district boundaries necessitated by such federal projects or the raising of required additional funds for the work may be authorized by following the pertinent portions of the procedure in section 15-2303 above.

5. Except for such projects as may be carried out by the federal government, any district formed under the provisions of subdivision 2 above shall thereafter continue as a river improvement district, as though formed under the provisions of section 15-2303.