After the torrential rains of April 2011, Mississippi River started swelling with flood water moving down from the northern states to the lower Mississippi River valley. According to the Los Angeles Times report of May 20, 2011, Mississippi River along Vicksburg crested at 57.1 feet (14.1 feet above flood stage),
moving at 13 mph, more than double its normal velocity of 5 mph, the U.S. Army Corps of Engineers said. To relieve pressure on river levees 17 floods gates have been opened at Morganza Spillway (see photo on right), just north Baton Rouge, Louisiana allowing an estimated 114,000 cubic feet of water per second pouring through the structure to the Atchafalaya Swamp. There are 125 bays on the Spillway, built in 1954 as a part of Congressionally authorized Mississippi River management plan after the 1927 Great flood when the river flowed over 80 miles width.
The opening of Morganza flood gates has reduced the rising water level in Mississippi River and relieved pressure on levees in heavily populated areas of Louisiana. However, the tragedy of toxic river flood water breaching and overflowing levees in Mississippi and Louisiana will unfold in coming weeks inundating millions of acres of agriculture land, swamp areas, and hundreds of communities in many towns engulfed by the overflowing flood water. This disastrous event of 2011 Great Flood would not be a big surprise to the agencies and public, if the following issues would have been addressed by the concerned agencies:
• Updates of torrential rainfall and resulting flooding risk prediction models considering the recent worldwide increase of rainfall intensity and frequency. Many scientists blame this increase on climate change mechanisms.
• Re-calibration and updates of river flood models considering river bed sediment profile changes over the years in the Deep South region, especially Mississippi and Louisiana states. The construction of levees has stopped the natural annual process of river flooding and natural spreading of the bulk of sediments in the floodplain.
• Rise in these sediment deposits as the river flows southwards to the delta has increased the risk of flood water level by: cresting just shy of the top of levees in many places, rising seepage levels and overflowing levees some places during the 2011 flood, and compromising structural integrity of levees and flood spillway structures.
• Periodic monitoring of river bed sedimentation level changes and maintenance of river channel bed is important to predict flood levels above the sediments. Was it done? Modern remote sensing technologies can expedite this monitoring and mapping process.
• Modernization of flooding risk maps is important to control sprawl of residential communities in flood plains, improve landuse planning, and enforce flood protective building design and construction. If it would have been done in time by federal and local agencies then the drowning of homes, businesses and communities resulting from 2011 flood disaster would have been reduced or avoided.