The dredge ship Potter is making sure that the Big River, shrinking under one of the worst droughts in modern history, stays deep enough.
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 per cent 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, Mississippi 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,” 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, imperilling 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 T 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.
Such river training structures help to reduce the amount of dredging necessary by making the river do much of the work. The result, he said, is that even if water reaches the levels that it did before, “we’ll still be in better shape than we were in ‘1988.”
The river’s problems are the main topic aboard the Motor Vessel Mississippi, a giant towboat fitted by the corps with meeting rooms and used during its annual low-water inspection trip, which included a public hearing in Alton, Illinois on Friday. Some of the speakers complained about the corps’ management of the river during last year’s floods, when water at Vicksburg was nearly 59 feet higher than it has been during this year’s drought. That is the nature of the river — an engineered system, managed but hardly controlled.
Col Christopher G Hall, the commander of the St Louis district of the corps, in comments to the commission on Friday, said, “We feel we can provide safe and reliable navigation” under projections over the next 28 days.
While the corps is keeping the main navigation channel of the Mississippi open, the same cannot be said for the harbours along the river. Four of the 19 harbours that the corps is responsible for keeping open on the lower Mississippi have been closed, and the corps has estimated that eight more would probably be closed if the drought continues over the next month.
That is why the Potter is here, keeping the channel to the river’s authorised navigation depth of nine feet. Built in 1932, the Potter has been around so long that the corps upgraded it to diesel from steam power in 2001. The dredge, pulling itself along steel cables with winches to move in precise lines and its engines and pump thrumming, works its way through the muck.
On this day, the operators had to raise the dustpan-shaped intake head every half-hour or so to clear a bit of cable or scrap. “It’s a real trashy spot right here,” said Randy Jowers, assistant master on the vessel. Bits that get past the dustpan clatter by the impeller with a clang that can be felt throughout the ship.
Down the river a bit, the floating offices of JB Marine Service south of St Louis are not actually floating these days. The landward side of the barge, moored by the banks of the river, rests instead on the emerging shore, tilted at the kind of angle that probably makes it difficult to keep pencils on desks.
Even at nine feet, the shallower Mississippi has been a trial for companies like American Commercial Lines in Jeffersonville, Indiana, which operates about 2,000 barges along the nation’s inland waterways. The company tows would normally take as many as 40 barges up and down the Mississippi in blocks several barges wide and long. Mark Knoy, the company’s chief executive, said “not only are we carrying half as many barges, the barges are loaded to two-thirds of their capacity.”
Below St Louis, the river levels keep dropping, he said, grimly. “There’s no plug at the bottom, and the water just keeps draining out,” he said.
Martin T. Hettel, senior manager for bulk sales at AEP River Operations, a subsidiary of American Electric Power, which operates 3,200 barges, said, “We’ll still move the nation’s freight, it will just take more barges and more towboats.”
If the weather does not improve, the situation could get much worse, said David R Busse, the chief of the engineering and construction division for the St Louis district of the corps. If the rains do not come, the river will continue to drop. There will be a precipitous fall of about two feet at St Louis toward the end of the year, when the reservoirs up the Missouri River, as scheduled every year, stop releasing water into the Mississippi.
“Right now we have a problem, but we’re managing it,” Busse said. “What happens when they turn it off?”
The American Queen, at least, is making the best of the river’s low levels: it will soon take passengers up into the scenic Cumberland River, which it normally could not do because of bridges that are too low, said Michael Hicks, a spokesman for the company. But this year, he said, “Because the water is so low, we’re able to go under the bridges.”