These changes are due to modifications of the river by the Army Corps of Engineers, say Robert Criss, Ph.D., professor of earth and planetary sciences in Arts & Sciences at Washington University in St. Louis, and Washington University undergraduate student Bethany Ehlmann, an earth and planetary sciences major in Arts & Sciences. Ehlmann presented her and Criss's findings April 1, 2004 at the 38th annual meeting of the North-Central Section of the Geological Society of America, held in St. Louis.
The emplacement of wing dikes and levees, mostly after World War I, and the building of six main-flow reservoirs between 1937-63 have created a river that Lewis and Clark would not recognize if they were here today. The structures on the river are responsible for a deeper river that is flooding more often in recent years, the researchers say.
"Flood stages are getting higher over time because of restrictions that have made river width narrower," said Criss. "If you make the river narrower to accommodate any given amount of flow, the river's got to get deeper."
This restriction, Criss said, can be blamed on a four- to nine- foot increase in flood stages along the lower Missouri River.
Wing dams, or wing dikes, are found approximately every 1,500 feet along the Missouri River, from outside St. Louis to Sioux City, Iowa, ostensibly for controlling the river for the barge industry.
"The ironic thing is that the Missouri River hardly has any
barge traffic; most of that is on the Mississippi," Criss s
Contact: Tony Fitzpatrick
Washington University in St. Louis