Droughts leave cargo riverboats high and dry

The Rhine, which is Europe's main waterway for cargo riverboats, fell to record low levels last summer

Increased droughts are forcing shipping companies to abandon some of the world's main river cargo routes, warns Ann Christina Sloek-Andersen.

Ms Sloek-Andersen is a senior director at global shipping giant Maersk.

"[Last summer] we had to switch a lot of cargo from river to rail in Europe," she says, "in order to keep the big German industry clusters in Baden-Württemberg, Bavaria and Hessen connected to the ports of Rotterdam and Antwerp."

More than 300 million tonnes of goods a year are typically transported by cargo riverboats on the wide Rhine River, which flows for almost 800 miles from Switzerland to the Netherlands, where it joins the North Sea.

Yet during the summer months of last year, record low water levels meant some vessels were able to carry just 25% of their usual load, so as not to risk running aground on the riverbed. This caused severe delays to shipping.

Ann Christina Sloek-Andersen says shipping giant Maersk had to switch from riverboats to rail

"There are lots of well-known German and Swiss blue-chip companies... that rely on inland waterways to get raw materials and products in and out," says Ms Sloek-Andersen.

The cargo Maersk's riverboats carry ranges from temperature-sensitive fresh produce and pharmaceuticals, to raw materials like chemicals, and car and machinery parts.

"We carry our customers' cargo on barges wherever possible," says Ms Sloek-Andersen, "because it means far less CO2 emissions compared to trucks."

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However, when the Rhine's levels fell last summer, Maersk says its existing partnerships with rail providers meant they were able to "jump in with extra capacity".

Rail, says Ms Sloek-Andersen, is the preferred alternative to river as they have a similarly low CO2 footprint, at around 20-30g of CO2 per tonne-km per year (gCO2e/tkm), as opposed to trucks that emit almost 140 gCO2e/tkm.

However, she adds that other companies had to switch to road freight.

And it wasn't just Europe that found itself high and dry last year.

"You could walk across the mighty Mississippi River - that's not something we were prepared for," says Sarah Schiffling, a supply chain expert, and assistant professor at Hanken School of Economics, Helsinki, Finland.

The Mississippi River is used to transport more than 500 million tonnes of freight a year, but last year record low water levels were estimated to have cost $20bn (£16.7bn) in economic damage.

"Droughts are not a new phenomenon," says Prof Schiffling, "but [last year] we saw droughts in multiple areas across the world, all at the same time. It had a massive impact on inland shipping."

In China, parts of the Yangtze River, whose surrounding provinces produce 45% of the country's economic output, were closed to ships because water levels were more than 50% below average.

Meanwhile, two-thirds of Europe experienced drought conditions in 2022, as the continent saw its worst dry spell in at least 500 years.

It comes as studies show that drought conditions are only expected to worsen in the years ahead.

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So what can be done to help river barges stay afloat? In Germany, one proposed solution is to deepen a shallow section of the Rhine.

This would enable cargo riverboats to carry at least an extra 200 tonnes, according to Germany's Waterways and Shipping Office.

But plans to deepen a 31-mile section of the World Heritage-listed Middle Rhine - where the river is lined with castles and vineyards - are controversial.

"Deepening and widening the area will have knock-on effects on the environment - flooding and destroying ecosystems," says Prof Schiffling. "And, of course, it doesn't solve the core problem. No matter how deep you make it, there's just not enough water."

Rather than swapping to land transport, one designer and operator of cargo riverboats, Germany's HGK, is now introducing vessels that can continue to sail in very shallow waters.

"Our shallow-water tanker, Synthese 18, can transport cargo weighing 300 tonnes - even if the water is only 1.05 metres deep," says Anke Bestmann, managing director HGK Gas Shipping.

HGK is now producing cargo riverboats that can sail through very shallow waters, such as this, the Synthese 18

The boat has a very short vertical distance between the waterline and the bottom of its hull, a measurement known as a "draft". To compensate for this lack of depth, the vessel is wider than older barge designs.

It is also made from a lighter-weight stainless steel, and the riverboat's design is said to allow for great uplift as it moves along the water.

Fellow HGK director Tim Godde adds that the firm is "convinced that inland waterway vessels will transport even more goods in future".

However, Maersk's Ms Sloek-Andersen says that the ability for a transportation firm to adapt, and switch from river to rail, and so on, is key.

"Having a single provider for all parts of a supply chain makes it much easier and quicker to react and mitigate negative impact if disruption occurs - like a low-water period on one of the main inland waterways of Europe," she says.