Mississippi flood of 1973 The Morganza Spillway was opened, flooding portions of the Atchafalaya River basin in Louisiana and causing the deaths of thousands of head of livestock and white-tailed deer. The 1973 flood was notable for nearly causing the failure of the Old River Control Structure above the Mississippi River Delta, which would have sent the Mississippi's main channel flowing into the Atchafalaya River and bypassing most of the delta region including the major port of New Orleans, Louisiana. In spite of record high flows, flood stages were not as high as past events. Red River Landing, Louisiana reached 58.22 feet on May
Mississippi River Basin Model 1937, 1943, 1945 and 1952 were reproduced, as well as hypothetical floods at different periods of the year. Tests on individual problems were conducted until 1971 but high costs and growth of computer modelling meant that the facility was put on standby. The last use was in 1973, when a potentially catastrophic failure arose at the Old River Control Structure. The model was used to show that the untested Morganza Spillway could be opened effectively, without diverting polluted water through New Orleans and Baton Rouge, as well as identifying levees that required topping up. In 1993 the site was taken