(a) The only purpose of this subchapter is to grant counties in this state the authority to issue bonds or warrants or to otherwise lend their credit for the acquisition and conveyance to the United States of the necessary right-of-way for waterways or navigable canals:
(1) the construction of which is authorized by federal legislation; and
(2) the cost of construction and maintenance of which is to be paid by the United States.
(b) This subchapter shall be liberally construed to accomplish that purpose.