West Atchafalaya Floodway and west by the Atchafalaya Basin protection levees, and on the south by the Gulf of Mexico. Farther downstream, floodwaters enter the Gulf of Mexico through the Atchafalaya River below Morgan City, Louisiana and the Wax Lake Outlet. West Atchafalaya Floodway The West Atchafalaya Floodway is a flood control structure of the Mississippi River and Tributaries Project located in the Lower Atchafalaya Basin in south-central Louisiana. It has a project design flood flow capacity of . The Atchafalaya Basin system comprises three floodways. Two of these, the West Atchafalaya Floodway and the Morganza Floodway, are at the northern end. Together
Morganza Spillway still open. All bays were closed on July 7, 2011. The Corps had estimated that it would take opening one-fourth of the spillway’s 125 bays — or 31 bays — to control the flow of the river through Baton Rouge in response to a forecast crest of anticipated on Tuesday, May 17, 2011, which must remain below of water per second through Baton Rouge to ensure the integrity of the levee system. Since Morganza never operated above , the flooding in the Atchafalaya Basin was considerably lower than had been anticipated during the initial estimates of . By May 29,