Flood-control Works in the Alluvial Valley of the Mississippi River. Letter from the Chief of Engineers Transmitting a Supplemental Report on Flood Control in the Alluvial Valley of the Mississippi River which Recommends Certain Extensions and Modifications of the Projects for Flood Control of the Mississippi River and Its Tributaries Set Forth in H. Doc. No. 90, 70th Congress, 1st Session, and Adopted by the Flood Control Act of May 15, 1928.