“Commerce is moving, albeit very slowly,” said Deb Calhoun, a senior vice president for the Waterways Council, a transportation industry group. “Ultimately, we need rain, and lots of it.”
Drought is pronounced across much of the country west of the Mississippi, including some two-thirds of the northern Plains states that drain to the Missouri River and then the Mississippi, U.S. Drought Monitor data show.
Precipitation totals rank among the 15th driest that Oklahoma, Missouri, Kansas, Iowa and South Dakota have seen for June through September. It has been Nebraska’s third-driest recorded stretch of summer into fall, according to the National Centers for Environmental Information.
Such a drastic constriction in water flows across such a large area has translated to an unusually lasting impact on Mississippi River levels. The last time dry conditions had such an effect on the river was a decade ago.
If those areas “were to stay dry through the rest of the year, levels could be even worse than we had in 2012,” said Jeffrey Graschel, service coordination hydrologist at the National Weather Service’s Lower Mississippi River Forecast Center. “It just remains to be seen how much rain we get over the next month to three months.”
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River levels are not expected to hit record lows just yet. It’s difficult to compare current conditions across the record books because the river’s banks have changed so dramatically from preindustrial times, Graschel said — on the Mississippi alone, waters pass through dozens of locks and dams. But if the current dry conditions surpass those observed in 2012, they might approach the severity of a 1988 low-water crisis, he said.
Long-term weather forecasts suggest no significant change in precipitation patterns in the coming weeks. Hydrologists predict sustained drought, as well as areas of newly developing drought across the western half of the country this month, according to the Climate Prediction Center.
While the center said it expects near-normal precipitation patterns over the next week or two across the Mississippi basin, bringing some chances for rain, dry conditions are predicted to resume for the latter part of October and into early November.
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In the meantime, the low river levels are causing costly problems, and even
exposed a 19th century shipwreck in downtown Baton Rouge.
Plaquemines Parish warned residents on Sept. 28 that drinking water drawn from the Mississippi contained elevated levels of sodium and chloride, a potential health issue for people on dialysis or low-sodium diets. As the southward river flow slackens, a layer of saltwater from the Gulf of Mexico is creeping up the Delta, forming a wedge at the bottom of the river because salt water is heavier than fresh water, Graschel explained.
To protect the community, the Army Corps of Engineers said Sept. 28 that it would build a sediment barrier across the river channel to prevent more salt water from flowing northward.
That work is in addition to the corps’ routine dredging of the lower Mississippi that has only become more important as river flow has waned. The corps dredges an average of about 265 million cubic yards of river bottom in the Mississippi Valley each year, at a price tag that totaled $2.45 billion in 2020, spokeswoman Lisa Parker said.
An estimate of ongoing emergency dredging work was not available, she said. But the low water conditions are making work that was already extensive more difficult, ensuring depths of at least 9 feet along 4,267 linear miles of channels, Parker said.
Parker noted that, though costly, the work to maintain a viable transportation network on the country’s inland rivers represents what the corps estimates to be $12.5 billion in transportation cost savings, because moving cargo over water is cheaper than on rail cars or tractor-trailers.
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For its part, the industry has limited the amount of cargo attached to any single towboat — only up to 25 barges, instead of the typical 40, Calhoun said. Still, barges continue to run aground. On the Ohio River, even, waters are low enough that barges got stuck this week near that waterway’s confluence with the Mississippi, transportation company American Commercial Barge Line reported.
“This situation underscores the importance of the inland waterways and the Mississippi River as an artery to commerce,” Calhoun said.
But others disagree, saying the problem demonstrates that nature can’t be tamed. The Mississippi has changed so much from its natural state, it has become “a volatile system,” said Robert Criss, a professor emeritus of earth and planetary sciences at Washington University in St. Louis. Though that volatility is often most evident during floods, Criss said his research shows it can affect the river on a day-to-day basis.
“You don’t want things being unpredictable, and that’s what we have,” he said. “We have an unpredictable river.”
Until significant rainfall arrives, river flow is getting some help, for now, as pools used to store floodwaters along the Ohio and Missouri rivers are being emptied to make room for winter storm runoff, Parker said. But that is only expected to continue through this month, she said — unless authorities decide to hold some of the waters back.
Then, they could be released should river waters drop to critically low levels in the coming months.
