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Title:	The Atchafalaya River Study : a report based upon engineering and geological studies of the enlargement of Old and Atchafalaya Rivers : including profiles and sections together with factual data which indicate the past rate and extent of progressive changes in Old and Atchafalaya Rivers from their head through Grand and Six Mile Lakes to the sea : all of which indicate the probable capture of the Mississippi River by the Atchafalaya River
Authors:	Latimer, Rodney A. Schweizer, Charles W.
Keywords:	Atchafalaya River Watershed (La.) Mississippi River. Geomorphology
Publisher:	United States. Mississippi River Commission. United States. Army. Corps of Engineers.
Abstract:	Section 8 of the Flood Control Act approved May 15, 1928, states that: "The project herein authorized shall be prosecuted by the Mississippi River Commission under the direction of the Secretary of War and supervision of the Chief of Engineers.'' The plan authorized by the above act provides for the control of the maximum probable flood that may occur in the Lower Mississippi Valley. The Mississippi River watershed is the largest drainage basin in the United States and the maximum probable flood in the latitude of Old River has been determined under the project as 3,000,000 cubic feet per second . This flood flow is to be routed to the sea by passing 900,000 cubic feet per second from the Red River backwater area into the Atchafalaya Basin at the latitude of Simmesport. Of the latter amount, a discharge of 650,000 cubic feet per second is to enter the Atchafalaya Basin through the main channel of the Atchafalaya River and a discharge of 250,000 cubic feet per second is to pass down through the West Atchafalaya Floodway. A discharge of 2,100,000 cubic feet per second is to be carried down the Mississippi River to the head of the Morganza Floodway, where a discharge of 600,000 cubic feet per second is to be diverted through the Morganza control structure into the Atchafalaya Basin. The Mississippi River below the Morganza control structure is to carry a discharge of 1,500 ,000 cubic feet per second to the head of the Bonnet Carre Floodway, where a discharge of 250,000 cubic feet per second is to be diverted into Lake Pontchartrain. The remaining water, 1,250,000 cubic feet per second, is to be carried down the Mississippi River into the Gulf of Mexico. The Chief of Engineers, U.S. Army, in letter dated 29 September 1950, subject: "Atchafalaya River Study," directed that the Mississippi River Commission prepare an engineering study of the rate and extent of the enlargement of the Atchafalaya River and its connecting link, Old River. This report finds that: {l) the Atchafalaya and Old Rivers have enlarged their channel capacities to such an extent that a discharge of from 50,000 to 100,000 cubic feet per second in excess of the project requirement for these streams can be discharged when project flood elevations occur at Simmesport, Louisiana; (2) the Atchafalaya and Old Rivers are continuing to enlarge and will, at their present rate of enlargement, capture the Mississippi River unless prevented by man-made structures; (3) the Atchafalaya-Old River channel will probably become the master stream in about 25 years unless restricted by regulating works; (4) the heavy sediment load being deposited below the unleveed channel will make it necessary to assist the Atchafalaya River in the development of an efficient single channel in the lower basin in order to pass necessary high-water flows. These improvements will tend to increase the rate of diversion, and any regulating structures should be commenced before or concurrently with improvement dredging in the lower basin; and (5) the Wax Lake Outlet is capable of passing the discharge for which it was designed but should eventually be improved to pass a somewhat larger discharge.
Description:	Technical Report
Rights:	Approved for Public Release; Distribution is Unlimited
URI:	http://hdl.handle.net/11681/30764
Size:	214 pages / 47.71 Mb
Types of Materials:	PDF
Appears in Collections:	Report