The project for the flood control of the Mississippi River in its alluvial valley and for its improvement from the Head of Passes to Cape Girardeau, Missouri, in accordance with the engineering plan set forth and recommended in the report submitted by the Chief of Engineers to the Secretary of the Army dated December 1, 1927, and printed in House Document Numbered 90, Seventieth Congress, first session, is adopted and authorized to be prosecuted under the direction of the Secretary of the Army and the supervision of the Chief of Engineers: Provided, That a board to consist of the Chief of Engineers, the president of the Mississippi River Commission, and a civil engineer chosen from civil life to be appointed by the President, by and with the advice and consent of the Senate, whose compensation shall be fixed by the President and be paid out of the appropriations made to carry on this project, is created; and such board is authorized and directed to consider the engineering differences between the adopted project and the plans recommended by the Mississippi River Commission in its special report dated November 28, 1927, and after such study and such further surveys as may be necessary, to recommend to the President such action as it may deem necessary to be taken in respect to such engineering differences and the decision of the President upon all recommendations or questions submitted to him by such board shall be followed in carrying out the project herein adopted. The board shall not have any power or authority in respect to such project except as hereinbefore provided. Such project and the changes therein, if any, shall be executed in accordance with the provisions of section 702h of this title. Such surveys shall be made between Baton Rouge, Louisiana, and Cape Girardeau, Missouri, as the board may deem necessary to enable it to ascertain and determine the best method of securing flood relief in addition to levees, before any flood-control works other than levees and revetments are undertaken on that portion of the river: Provided, That all diversion works and outlets constructed under the provisions of sections 702a, 702b to 702d, 702e to 702g, 702h, 702i, 702j, 702k, 702l, 702m and 704 of this title shall be built in a manner and of a character which will fully and amply protect the adjacent lands: Provided further, That pending completion of any floodway, spillway, or diversion channel, the areas within the same shall be given the same degree of protection as is afforded by levees on the west side of the river contiguous to the levee at the head of said floodway, but nothing herein shall prevent, postpone, delay, or in anywise interfere with the execution of that part of the project on the east side of the river, including raising, strengthening, and enlarging the levees on the east side of the river. The sum of $325,000,000 is authorized to be appropriated for this purpose.
All unexpended balances of appropriations prior to May 15, 1928, made for prosecuting work of flood control on the Mississippi River in accordance with the provisions of section 702 of this title, are made available for expenditure under the provisions of sections 702a, 702b to 702d, 702e to 702g, 702h, 702i, 702j, 702k, 702l, and 702m of this title.