Danube hits record 31cm low as drought idles central European reactors

The Danube has dropped to a record low of 31 cm in Budapest, idling nuclear reactors in Romania and Hungary as a fierce drought parches central Europe.

The river hit the mark on July 28, Xinhua reported, edging below the 33 cm low set in October 2018. Weeks of heat and thin rainfall have drained the Danube from Germany to the Black Sea, forcing barges to sail half-empty and pulling water back from irrigation intakes across the basin.

The Danube is Europe's second-longest river and a workhorse of the continent's economy, carrying 62.7mn tonnes of cargo in 2025, cooling nuclear plants and watering farmland along its path to the sea. When it fails, the damage lands everywhere at once, in power grids, shipping lanes and food supplies.

Officials have tried to steady nerves. "The population will not feel a thing, no matter how difficult the situation gets," Romanian State Secretary Cristian Bușoi said on August 10, as engineers battled to keep water reaching the country's only nuclear plant.

That plant, Cernavoda, powered down one of its two reactors in late July as the river retreated from its cooling intake, and Bucharest declared a 30-day nationwide state of alert on July 31. The navy set off a controlled explosion on August 3 and later sank four rock-laden barges to steer water towards the intake, works that raised the level by only a few centimetres. Cernavoda's two units supply about 18% of Romania's electricity, and officials warn the second reactor may still have to go offline.

The strain ran downstream. Hungary's Paks station, which provides about 40% of national power, wound down a unit and came within a millimetre of shutting its last turbine, which would have been the first full stoppage in the plant's 44-year history before levels crept up. Serbia throttled its two Iron Gates hydropower dams to as little as 20-30% of capacity.

On the water, the drought has wrecked the summer cruise season, with sailings on the Danube, the Rhine and the Main cancelled or rerouted. Some 186 passengers were evacuated when the Viking longship Ullur ran aground near Vidin, Bulgaria, in the early hours of July 28, and cargo skippers are running part-loaded to stay afloat.

As the water pulls back it has bared the riverbed's buried history: a cluster of scuttled German warships at Prahovo in Serbia, the wreck of Budapest's Franz Joseph bridge, the foundations of a Roman crossing near Gigen in Bulgaria and, close to Ruse, mammoth bones from the Ice Age.

The collapse is turning into a fixture of Europe's summers. The Danube sank to comparable depths in the drought of 2022, stranding grain barges and starving irrigation pumps along the Bulgarian-Romanian border, and it and Poland's Vistula struck fresh record lows in 2025 during an early heatwave that hydrologists linked to a warming climate.