Morganza Spillway stilling basin, and substantial flooding occurred in the Atchafalaya Basin. After the 1973 flood, the structure was restored to its original condition. The issue of opening the gates to keep the Mississippi in its current place was next raised in May 1983. Although the gates were not opened, Louisiana Highway 1 running across the spillway was closed, and the Corps of Engineers built a ring dike and put a blanket of earth across a section of the spillway to contain water pouring underneath it. During the Great Mississippi and Missouri Rivers Flood in 1993, officials decided to leave the gates
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