Old River Control Structure such that the volume of the two rivers is split 70%/30%, respectively, as measured at the latitude of Red River Landing. This flow split was not based on science, but rather was based on the approximate flow allocation between the two rivers that existed at the time of construction. Water diverted at Old River flows into the Atchafalaya Basin, first entering the Red River, then continuing down the Atchafalaya River to the Gulf of Mexico, bypassing Baton Rouge and New Orleans (see diagram). The Morganza Floodway, between the Mississippi and the Atchafalaya Basin nearby downstream, is normally closed, but can
1st Missouri Regiment of Colored Infantry of Morganza, Dept. of the Gulf, to September 1864. 2nd Brigade, 1st Division, United States Colored Troops, District of Morganza, Dept. of the Gulf, to September 1864. Port Hudson, La., Dept. of the Gulf, to September 1864. Brazos Santiago, Texas, to October, 1864. 1st Brigade, 2nd Division, United States Colored Troops, Dept. of the Gulf, to December 1864. Brazos Santiago, Texas, to June 1865. Dept. of Texas to March 1866. Ordered to Baton Rouge, La., March 23, 1864, and duty there till June. Ordered to Morganza, La., and duty there till September. Expedition from Morganza to Bayou Sara September 6–7.