The Danube water level is falling again in Hungary after a temporary rise, renewing concerns over the cooling-water supply of the Paks Nuclear Power Plant. With forecasts pointing to another sharp decline, the government is accelerating an extraordinary engineering project that could raise the river by as much as one metre near the plant’s cooling-water channel.
Official water management data showed the Danube at -118 centimetres at Paks on Thursday morning, down from -115 centimetres around midnight. The National Water Directorate’s forecast indicated that the decline could continue over the coming days.
As Portfolio reported, the renewed fall comes shortly after river levels had temporarily improved. On Thursday morning, the level was already nine centimetres below the figure measured a day earlier.
Why the Danube water level is critical for Paks
For foreign readers, the importance of the river to Hungary’s electricity system cannot be overstated. The Paks Nuclear Power Plant, located about 100 kilometres south of Budapest, uses Danube water for cooling.
Low river levels can therefore restrict how much cooling water can safely be taken from the river, forcing the plant to reduce electricity production. The Hungarian government says low water levels have already required output restrictions several times this year.
Authorities are now preparing for the possibility of another rapid fall. According to the government, without intervention the Danube water level near Paks could approach -140 centimetres again next week, a level that could threaten the plant with a complete production shutdown.
The economic stakes are also substantial. The government estimates that a shutdown of Paks would cost the Hungarian budget at least HUF 50 billion (around EUR 137 million) per month. The emergency river works themselves are expected to cost roughly HUF 6 billion (EUR 16.5 million). The euro conversions are based on the Hungarian National Bank’s latest available official exchange rate.
As we wrote today, the danger is not over, Budapest water supply is under pressure again
A stone barrier will be built across the Danube
The main solution is an unusual structure known as a riverbed sill, or fenékküszöb in Hungarian.
Economy and Energy Minister István Kapitány demonstrated the planned structure in a video published after the government’s meeting at Paks. According to a separate Portfolio report featuring illustrations from Kapitány’s video, the sill will run perpendicular to the flow of the Danube and will require more than 150,000 tonnes of stone. Work is to begin simultaneously from both banks.
Before the main structure is built, workers will create a protective stone layer on the riverbed to prevent the current from undermining the sill. Large, multi-tonne rocks will then be placed into the river. The government says an initial 35,000 cubic metres, followed by another 110,000 cubic metres of stone, will be used.
The aim is to prevent the water level at the cooling channel from dropping below -90 centimetres. According to the plans, the structure could raise the water level in the relevant section by as much as one metre.
Two 80-metre barges prepared as emergency backup
The permanent structure will take several weeks to complete, so authorities have also prepared a faster temporary solution.
Two 80-metre-long barges are being positioned near Paks. If the Danube falls too quickly before the sill is finished, the vessels could be deliberately sunk at designated locations. Officials estimate that this could temporarily raise the water level by around 20 centimetres.
Work on the riverbed sill is expected to continue around the clock, with the government aiming to complete the project within approximately three to four weeks. Around 100 military personnel have also been assigned to support the operation.
Kapitány stressed that the unusually fast timetable would not override nuclear safety requirements: water management, energy and nuclear experts are to be involved throughout the project.
For now, the slight recovery seen on the Danube has proved temporary. With the Danube water level falling again and forecasts pointing towards renewed critical conditions, the next few days will determine whether the emergency barges are needed before the much larger riverbed intervention can begin protecting Paks on a longer-term basis.
As we wrote yesterday: PM Magyar announces moves to raise the Danube near Paks nuclear power plant
