(a) The State of Arkansas agrees that the United States of America, the Secretary of the Army of the United States on behalf of the United States, or any of its agencies thereunto legally authorized:
(1) Shall be, and each is, fully authorized, empowered, and enabled within this state to exercise the rights of eminent domain and to obtain and acquire property and property rights, flowage rights, rights-of-way, and servitudes or easements, or options therefor, in this state, either by voluntary agreements with the owners thereof or by condemnation proceedings under the laws of the United States in pursuance of authority conferred by law; and
(2) Upon the filing of any condemnation proceedings, shall have the right to take immediate possession of the property to the extent of the interest sought to be acquired, and proceed with the construction of levees, levee foundations, channel rectifications, floodways, reservoirs, spillways, diversions, drainage canals, or other flood control or drainage works thereon. However, in the event immediate possession is taken as herein provided, adequate provision shall be made for the payment of just compensation to the party or parties entitled thereto. Furthermore, those condemnation proceedings shall be diligently prosecuted in order that compensation shall be promptly ascertained and paid.
(b) Nothing contained in this section shall be construed in such manner as to relieve any levee district, drainage district, or levee and drainage district from any liability to the owners of property taken or damaged, whether condemnation proceedings are instituted by the United States, or by such district. In any taking by the United States, or any of its agencies, the district shall be liable to the property owner for any damages compensable under existing Arkansas law, whether or not it is compensable under the laws of the United States.