Atchafalaya Basin 1973. This water floods the Atchafalaya Basin between the levees along the western and eastern limits of the Morganza and Atchafalaya basin floodways. The control of the river's floods, along with those of the Mississippi River, has become a controversial issue in recent decades. The US Geological Survey (USGS) reports that Mississippi River delta salt marshes are wetlands degrading at a rate of 29 square miles per year. The Atchafalaya River Deltas are the only locations of land growth along the Louisiana Gulf Coast. During the early 20th century, the Atchafalaya River Basin was designated as a spillway for floods
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,