Drought May Sink Mississippi River Commerce

New York Times
20 August 2012
By John Schwartz

The Potter is scooping this stretch of the Mississippi River's navigation channel just south of St. Louis, the ship's 32-foot-wide head sucking up about 60,000 cubic yards of sediment each day and depositing it via a long discharge pipe a thousand feet to the side in a violent, muddy plume that smells like muck and summer.

The Army Corps of Engineers has more than a dozen dredging vessels working the Mississippi this summer. Despite being fed by water flowing in from more than 40 percent of the United States, the river is feeling the ruinous drought affecting so much of the Midwest. Some stretches are nearing the record low-water levels experienced in 1988, when river traffic was suspended in several spots.

That is unlikely this year, because of careful engineering work to keep the largest inland marine system in the world passable. But tow operators are dealing with the shallower channel by hauling fewer barges, loading them lighter and running them more slowly, raising their costs. Since May, about 60 vessels have run aground in the lower Mississippi.

The low water is not just affecting the 500 million tons of cargo like coal, grain and fertilizer that move up and down the river each year. The owners of the American Queen, a paddle-wheel steamboat that takes passengers on tours along the inland waterways, decided not to send the boat below Memphis on a trip to Vicksburg, Miss., this month. The water was deep enough, said Tim Rubacky, a company spokesman, but after conferring with the corps and the Coast Guard, the company decided that the likelihood of a barge accident and ensuing traffic closures would be too great.

"It's kind of like a truckful of watermelons spilling over on the expressway," Mr. Rubacky said. "Everything's going to come to a halt." The boat tied up at Memphis and sent the passengers on to Vicksburg by bus, he said. The volume of water coming down the river is so much lower than normal this summer that a wedge of saltwater is creeping up the Mississippi toward New Orleans, imperiling local water supplies drawn from the river. The corps is building a sill -- basically, a dam of sediment -- in the river below New Orleans low enough to block the flow of saltwater while letting boats pass.

When the Mississippi is low, the flow slows and sediment settles, causing the river to silt up and obstructions to form, said James Pogue, a spokesman for the corps in Memphis.

Since 1988, when record low water on the Mississippi caused navigation to shut down, the corps has engineered ways "to help the river keep itself open," he said, building new features like dikes that stick out into the river and "sort of act like nozzles to speed up the flow of the river" to scour the bed.