KANSAS CITY -- Barge traffic has yet to show any ill effects from the reduction beginning last Friday of Missouri River water flow into the drastically low Mississippi River, said Ann M. McCulloch, director of public affairs and communications for the American Waterways Operators trade group.

That is likely to change, though, in the next two weeks if nothing is done to increase navigability on the Mississippi, especially in the sector from St. Louis to Cairo, Ill., where the water is low and large rock formations called pinnacles may lead river vessels to go aground in shallow waters. The Army Corps of Engineers is reducing the amount of water from the Upper Missouri River flowing into the Mississippi, an annual process. The 2012 drought, however, has meant that Mississippi River levels already have fallen significantly.

As a result, American Waterways Operators is taking its case to the Obama administration and the U.S. Army Corps of Engineers, arguing that the current timeline to ease the situation would result in major dislocations in moving the $7 billion in agricultural commodities and other commodities such as coal and petroleum to market, Ms. McCulloch said.

“The Corps has said work to remove the pinnacles will not begin until next year. This is work that needs to begin now,” she said. Doing nothing until 2013 could create a true economic crisis, she contended.

The stumbling block to more immediate action, Ms. McCulloch said, is “contracting procedures” that could be overcome relatively easily. She acknowledged producers were likely to turn to rail and truck transportation in the event the Mississippi River stays excessively low, but she argued that would raise costs significantly to farmers and energy manufacturers.

A St. Louis area grain executive said soybean exports were likely to be the most affected among the leading agricultural commodities because export demand for soybean has been more robust than recent demand for wheat and corn.