(CNN) — The lowest water levels in the Mississippi River in a decade, caused by a severe Midwest drought, have closed the vital channel to barge traffic at a crucial time of the year for the transport of crops from the nation’s heartland.

The Army Corps of Engineers has been dredging portions of the river for the past week in an attempt to deepen channels and get barge traffic moving again. But the closures have caused a massive tie-up in the nation’s already struggling supply chains.

The low water has also been responsible for eight barges running aground during the last week, according to a report from the US Coast Guard.

As of Friday, the Coast Guard reports that there are 144 vessels and 2,253 barges queued up and waiting to get through two stretches of the river where traffic has been halted — one near Memphis, the other just north of Vicksburg, Mississippi. While the Coast Guard statement said it hopes to resume traffic again as soon as late Friday, it couldn’t say for certain when that would happen.

“The Coast Guard, [Army Corps of Engineers] and river industry partners are working towards the goal of opening the waterway to restricted one-way traffic when it has been determined safe to do so,” said the Coast Guard’s statement.

Even when barges start moving once again, they’ll be forced to carry as much as 20% less cargo than normal in order to not ride too deep in the water. And rather than a single vessel moving between 30 to 40 barges at one time as they normally do, they’ve been forced to move no more than 25 barges on each trip due to the more narrow channels.

The combination of fewer barges per trip, and less cargo per barge, has cut the capacity of barges moving on the river by about 50% even before the recent river closures, said Mike Seyfert, CEO of the National Grain and Feed Association. And that has sent the rates that shippers are paying soaring.

“From what we hear from members, that has resulted in record levels of barge rates, and that’s being driven by the fact that there is limited traffic,” Seyfert said.

River barges are still a major method of moving cargo within the United States, especially for agricultural products.

About 5% of all freight in the United States moves on river barges when measured by the weight of the cargo and the distance traveled, according to data from the Bureau of Transportation Statistics. The shippers who use river barges have few, if any, affordable alternatives.

Most of the barge traffic moving south this time of year is carrying agricultural products. Many of those moving north are loaded with fertilizer that farmers will need for their next planting.

“This time of year, the river is crucial for moving product,” said Seyfert.

The region that feeds water into the Mississippi River has been hit especially hard by a regional drought since July, leading to sharply lower levels around Arkansas and Tennessee, according to data tracked by the US Geological Survey. The two highest levels of drought have recently expanded across the Midwest and the South, according to last week’s US Drought Monitor.

Compounding supply chain woes
This is just one more stumbling block for US supply chains that are still struggling to recover from disruptions since the start of the pandemic two and a half years ago. West Coast ports, where most of the nation’s imports arrive by container ship, are still congested, too.

And while a freight railroad strike was narrowly averted last month, even the freight railroads themselves admit they are providing substandard levels of service as they struggle with their own labor shortages.

The Mississippi is not the only river facing low water levels and posing economic problems for those who depend upon on those rivers.

Prolonged drought in the western United States has taken the reservoirs in the Colorado River basin to historically low levels. That water supply is crucial for both hydroelectric power and the supply of water needed by western states.

And in Germany, river levels fell on the Rhine River in August, limiting barge traffic there, including coal shipments needed to supply power plants.

US drought getting worse
There are few signs of relief for the low water levels on the Mississippi.

Another dry week across much of the Central and Southern US has led to “intensifying drought conditions across much of the Great Plains, Mississippi Valley, and Midwest,” according to the latest update from the US Drought Monitor.

“A very dry pattern during the past month” has led to significant degradation in crops and river levels, the summary noted.

Up to 57% of Arkansas is experiencing severe drought, the highest in five years; three months ago, it was less than 1%. To the north, the amount of Missouri judged to be in severe drought conditions has doubled each of the past two weeks and is now up to 30% of the state.

These widespread drought conditions are also impacting other important tributaries to the Mississippi River. More than 70% of the Missouri River basin is facing drought conditions this week, meaning less water is entering the Mississippi River, further lowering its levels.

A University of Missouri weather station in Columbia, for example, reported just 6.46 inches of rain between June 2 and September 27, the Drought Monitor noted. That is more than 11 inches below normal and the driest such period for that location in 23 years.

No significant rain is expected over the next week in the Lower Mississippi and Ohio River valleys, and water levels are expected to drop further.

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