Today, Louisiana faces the threat of major flooding from the Mississippi River much as was experienced during the Great1927 flood. In fact, according to measurements in Vicksburg, Mississippi, the river is actually 1.3 feet higher than the record 1927 flood. This makes for an unprecedented event.
The 1927 flood was called “America’s greatest peacetime disaster”. The floodwaters covered 26,000 square miles in 170 counties across seven states. Over 931,000 people were displaced with the loss of 162,000 residences and 92,000 businesses.
St Bernard residents well remember what occurred back then. The city fathers of New Orleans decided that it was in their interest to blow up the levee in St. Bernard Parish. They flooded communities below the city in order to protect New Orleans from the high waters caressing their levee’s top.
This was done and the people of St. Bernard were submerged for months. But what actually saved the city occurred much further north. The flood waters that covered Louisiana filled the Tensas Basin when the levee broke in Pendleton, Arkansas on April 21st and flowedinto theAtchafalaya Basin. Then the river crevassed at Cabin Teele, Louisiana, just north of Vicksburg, on May 3rd. Following that the levee disintegrated along Bayou des Glaises in north Louisiana. Finally, the levee at Melville crevassed. The entire Deltaic Plain flooded. The waters covered a region from the west bank of the Mississippi River levee all of the way to the Prairie Terrace at Lafayette. Estimates of the flow rate are about 1.2 million cubic feet per second moving at nearly 30 mph along a 20 mile front.
“We were awakened Thursday morning to find the lake [Spanish Lake] had filled and was bursting its banks pouring perfect torrents into the town from two directions…no power on earth could have saved us from inundation by the greatest of all floods since the days of Noah.”(The New Iberia Enterprise, May 28, 1927)
Nearly the entire center of Louisiana had gone under water west of the Mississippi River. One must add to that deluge the volume of water from Mississippi River crevasses in to the east. This flooded everything from below Memphis to just north of Natchez.
Taking the Mississippi’s east bank and west bank floods together, one can appreciate the vast volume of water that escaped from the channel of the Mississippi River in 1927 taking pressure off of the levees in New Orleans.
As we stand today, the levee system is substantially better engineered than it was in 1927. That should provide some sense of security to those of us living down river. However, it is wise to remain alert because it is difficult to imagine that the volume of water diverted through the Bonnet Carre’ Spillway and the Morganza Spillway is sufficient to match the volume of water diverted in 1927 through the numerous crevasses that occurred along the length of the Mississippi River back then.
At its maximum Morganza can release only 600,000 cubic per second and Bonnet Carrre’ about 250,000 cubic feet per second. That makes a total of 850,000 cubic feet per second…about 450,000 short of the 1.3 million cubic foot flow generated by the 1927 crevasses in Louisiana alone.
In which case, New Orleans may face the largest Mississippi River flood-stage in recorded historic times. It is essential, therefore, that everyone maintain vigilance. The crest will pass on May 23rd. However, high river water will be with us for weeks before and several weeks after that event. This will be the most supreme test of our levee system to date.
Be mindful, no one is expecting any problems to occur. But preparation is the best safeguard to prevent disaster. Plan for the worst and pray for the best. Likely, the New Orleans area will only experience a few weeks of stress and concern.
In the meantime, our hearts must remain open to those people who have lost their homes in the effort to save ours. Their loss is great and not the result of a natural disaster, but a human calculation for the greater good…saving two major metropolitan areas. We owe these people a debt of gratitude. Whatever help they may need to reconstruct their lives and homes is due them.