The decision to breach the levee appears to be working. The Ohio River at Cairo peaked at 61.72 feet just before the blast. By 6 a.m. this morning, the level has dropped to 60.62 feet. The previous recorded for the river was 59.5 feet in 1937, which is still less than what is was this morning. The breach could cause river levels to fall by three to four feet over the next few days, according to Maj. Gen. Michael Walsh, commander of the Corps' Mississippi River Valley Division. The city of Cairo's residents were ordered to evacuate because of the induced flooding.
Missouri took the Corps to court over the intentional breaching of the levee. The state argued that the flooding would deposit silt over the 130,000 acres of productive farmland. The silt would take years to clear. The U.S. Supreme Court refused to interfere, making it possible for the Major General to blow the levee. Maj. Gen. Walsh stated that the fate of Cairo was one of many factors in his decision. Water levels and flooding have hit record highs in many spots, putting strains on systems meant to prevent uncontrolled floods and the resulting loss of life and property.
The breaching of the levee, I think was necessary action. The damage caused by not breaching the levee would significantly outweigh the damage caused by breaching the levee.
A video can be found of the blasting by following this link Click here