(a) The State of Arkansas agrees:
(1) 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, 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 in connection with the construction of the works provided for in any such adopted and authorized project; and
(2) Upon the filing of any such condemnation proceedings, the United States shall have the right to take immediate possession thereof to the extent of the interest sought to be acquired and proceed with the construction of flood control and drainage works thereon, as provided in the authorized and adopted project. However, in the event immediate possession is taken as provided in this section, adequate provision shall have been made for the payment of just compensation to the party or parties entitled thereto, and provided further that such condemnation proceedings shall be diligently prosecuted in order that the 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 the property taken or damaged, whether condemnation proceedings be instituted by the United States, or by such district, and 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.