The jurisdiction of the Mississippi River Commission is extended so as to include that part of the Arkansas River between its mouth and the intersection thereof with the division line between Lincoln and Jefferson Counties, and any funds which are appropriated by Congress for improving the Mississippi River between Head of Passes and the mouth of the Ohio River, and which may be allotted to levees and bank revetment, may be expended within the limits of said extended jurisdiction under the direction of the Secretary of the Army, in accordance with the plans, specifications, and recommendations of the Mississippi River Commission, as approved by the Chief of Engineers, and upon like terms and conditions for levees and bank revetment upon any part of the Mississippi River now under the jurisdiction of said commission, and in such manner as will best promote and accomplish the purposes for which commission was created, in so far as the territory hereby added to its said jurisdiction may be involved.