The Mississippi and Missouri rivers were once dramatically wider, but a century of re-engineering has constricted their courses, making "flood magnification" inevitable.
"The floodwaters are starting to ebb in the swollen Mississippi, which in the past few weeks has seen its worst flooding in 15 years. Since May, at least 24 people have died from the torrential rains and flooding, more than 38,000 people have evacuated their homes and an estimated 5 million acres of corn and soybean have been waterlogged. But as the great mop-up begins, some scientists contend this is one natural disaster that is by no means just natural: It is the dramatic result of more than 100 years of narrowing and constricting the river.
[Scientists] charge that structures built by the U.S. Army Corps of Engineers to aid the shipping industry are contributing to the flooding. They're calling for the National Academy of Sciences to have oversight over Army Corps river projects, and for the federal agency to refrain from building structures that exacerbate the floods.
Even before the recent deluge, scientists sounded the alarm. Back in March, weeks before the floods occurred, Criss, Pinter and professor Timothy Kusky of St. Louis University sent a letter to the commander for the St. Louis district of the Army Corps of Engineers, critiquing the new structures that the agency puts into the Mississippi and Missouri to make it easier for large barges to navigate the area.
The dramatic reengineering of the Mississippi through levees and other structures has been going on for over 100 years. Way back in 1837 when then-Lt. Robert E. Lee of the Army Corps of Engineers mapped the Mississippi at St. Louis, it was almost 4,000 feet wide. Today it's just 1,500 feet wide at St. Louis. The Missouri river has also been drastically shrunk.
Now that the river can't naturally spread out on its flood plain or meander, the extra water under flooding conditions has nowhere to go."