Drought-driven low water levels on major rivers such as the Rhine, Danube, Loire and Po are crippling inland navigation, slashing barge capacity and sharply raising freight costs, the International Transport Forum warns.
With climate change expected to deepen hydrological droughts, supply chains reliant on river transport face mounting delays, congestion and economic losses across Europe, the US and other regions.
Against the backdrop of drought conditions seen across several parts of the world, record-low water levels in major rivers disrupted inland navigation, reduced freight capacity, raised transport costs and exposed the vulnerability of supply chains that depend on rivers, according to the International Transport Forum (ITF).
Over the past few months, major European rivers including the Rhine, Danube, Loire and Po have experienced record-low water levels. The ITF warned that summer river levels could decline further in the coming years as hydrological droughts increase across many regions.
On the Rhine, long-term average summer discharge could fall by as much as 10 per cent by 2050 under high climate-change scenarios.
The disruption was particularly stark in August 2026. Barges travelling from Rotterdam and Antwerp through the middle Rhine were able to load only around 15 per cent of their normal cargo-carrying capacity to avoid grounding. On the Danube, barge capacity fell to around 30 per cent of usual levels.
In more severe cases, low water can make stretches of rivers completely unnavigable, the ITF said in a new factsheet.
The consequences were significant because inland waterways remain a major part of freight networks. In Belgium, China, the Netherlands and Romania, they account for between 15 and 45 per cent of freight transport measured in tonne-kilometres.
The Rhine, Europe’s most important inland waterway, carries fuels, chemicals and grains across national borders, while 92 per cent of US agricultural exports are transported by river.
Lower loads mean more vessels and more journeys are required to move the same amount of freight.
“When vessels carry less cargo, more journeys and more vessels are needed to move the same volume of goods. But additional capacity is not always available. Freight rates can rise sharply as operators compete for limited capacity, adding costs and uncertainty for businesses dependent on river transport,” the ITF said.
The knock-on effects can extend through ports and entire supply chains. Cargo can remain stranded or stored for longer when it cannot be moved inland, making ports congested, while vessels may themselves become stuck as water levels fall. “Supply chains that depend on river transport for raw materials and finished goods can face higher costs and delays,” it said.
According to the factsheet, low water on the Rhine in 2018 was associated with a 0.4 per cent decline in German gross domestic product, while industrial production has been estimated to fall by around 1 per cent during a month with 30 days of low water.
“For communities that rely directly on rivers, the consequences can be even more immediate. Severe droughts on the Amazon in 2005, 2010 and 2016 disrupted inland navigation and isolated local populations, limiting access to food, fuel, medicines and essential services including healthcare and education,” it said.
Shifting freight away from rivers was not always straightforward. Rail networks in many countries were already heavily used and can themselves be disrupted by extreme heat. Moving cargo by road requires far greater capacity: replacing a barge carrying 1,500 tonnes of dry bulk would require around 60 trucks carrying 25 tonnes each.
The ITF said governments and businesses were therefore turning to a mix of adaptation measures. These include better water-level forecasting, shallow-draft vessels, water retention, reservoir releases, emergency dredging and increasing storage or stocks ahead of expected low-water periods.
Germany, for example, provides forecasts for water levels on the Rhine, Danube and Elbe up to six weeks in advance.
“Vessel design can also make a difference. Ships designed to operate in shallow water can continue carrying freight when conventional vessels have to reduce their loads,” it said.
Other measures included retaining water during wetter periods for release during drought, releasing reservoir water to maintain navigability, emergency dredging and increasing storage or stocks ahead of expected low-water periods.
But the ITF cautioned that no single intervention can keep rivers navigable under all drought conditions.
It said greater multimodal flexibility — maintaining viable connections between waterways, rail and road — would be increasingly important as climate change puts additional pressure on freshwater resources and makes river transport less predictable.