In any county or counties of the State of Nebraska in which the United States, or any of its departments or agencies shall be authorized by Congress to construct works for flood control, watershed protection and flood prevention and drainage programs of the State of Nebraska or any of its agencies or in cooperation with the program of natural resources districts or similar public districts the county or counties, if in its or their opinion the construction is necessary for the public welfare, may: (1) Enter into an undertaking, in the name of the county, to hold the United States of America free from any damage to persons or property resulting during the construction or after the completion thereof; (2) contract with the federal government, in the name of the county, that when such work is completed the county will maintain, keep in repair, and operate such works of improvement; (3) furnish all necessary lands, rights-of-way, and easements as provided in section 23-320.10 ; (4) enter into agreements with other county governments on provisions for cooperative programs of resource development; (5) establish watershed boundary lines for taxation purposes so that property within the perimeter of the defined drainage-way will be assessed for the financing of the program for improvement; and (6) appropriate such funds as may be needed to carry out and finance the program as outlined in sections 23-320.08 to 23-320.12.