A new heat wave covers the Balkans and a large part of the Danube basin. In the period from July 31 to August 6, the temperature in a number of countries of the region will reach 35-40 degrees, which will intensify the drought and complicate the situation on the Danube, where the water level has already fallen to multi-year, and in some places, record lows.
The highest temperature is predicted in Serbia, Croatia, Montenegro, Albania, North Macedonia and Hungary. Belgrade, Novi Sad, Zagreb, Podgorica, Tirana, Skopje and Budapest are expected to be mostly 37-40 degrees. In Sarajevo, the temperature will reach 35-37 degrees.
In Bulgaria and Romania, the heat will be less intense at first, but by August 4-5 Bucharest is expected to reach 36-37 degrees. In Moldova, the temperature will rise from 30 degrees on July 30 to 37 degrees on August 4-5. In the Odesa area and the Ukrainian part of the Danube Delta, 27–32 degrees are expected, but the night temperature in early August may reach 24 degrees.
In the upper part of the basin, the situation also remains difficult. In Vienna, July 31 is forecast to reach 39 degrees, and August 3-4 - up to 38-39 degrees. In Budapest, the temperature from July 31 to August 5 will be mostly 38-40 degrees. Isolated thunderstorms in Austria may cause a temporary rise in water levels, but prolonged heat will not quickly make up for accumulated precipitation deficits.
Water levels on the Danube, Sava and Tisza in Serbia are below low navigation marks. In Croatia and Serbia, silting has already led to the appearance of large sand shoals, the grounding of small vessels and the surfacing of old sunken ships, which pose an additional danger to navigation.
Due to insufficient depth, barges and tankers in some areas use only 30-40% of their carrying capacity. In July, Serbia received only about 25% of the planned volume of imported fuel via the Danube. The production of Serbia's largest HPP, Djerdap-1, has dropped to about a third of its normal level.
In Romania, the flow of water into the Danube has dropped to about 1.65 thousand cubic meters per second, compared to the July average of about 4.75 thousand cubic meters. The low water level led to the shutdown of both power units of the Chernavode NPP, which uses Danube water for cooling. In Hungary, the restrictions affected the Paksh NPP.
On the Bulgarian-Romanian section, navigation was restricted near the islands of Belene, Vardym and Batyn. Vessels are forced to wait for permission to pass and reduce loading. At the end of July, a passenger ship also ran aground on the Danube, despite current draft restrictions.
Analysis of consequences for ten Danube countries
In Germany and Austria, low runoff in headwaters means less water flowing downstream. Short-term showers may cause local rises in water levels, but sustained recovery requires prolonged rainfall throughout the upper and middle basin.
For Slovakia and Hungary, the main risks are related to restrictions on barge loading, reduced river tourism, disruptions in the supply of fuel and raw materials, and strain on energy infrastructure. In Budapest, the level of the Danube fell below the previous minimum values, and tourist flights were suspended in some directions.
Croatia and Serbia are already experiencing the direct impact of silting on the transportation of fuel, industrial raw materials, agricultural cargo and port operations. Sand shoals and sunken ships closer to the surface pose an additional danger.
For Bulgaria and Romania, the low water level means a reduction in the draft of ships, queues in narrow areas, stoppage of ferry crossings, rising costs of transporting grain and risks for energy. Romania is a key link in the route between the Ukrainian Danube ports and Constanta, so the delays extend to the entire lower Danube corridor.
Moldova has a short access to the Danube through the port of Giurgiulesti. It is located on the seaward side of the river and has a greater depth than many inland ports, so it is less directly vulnerable to the shallowing of the middle reaches of the Danube. However, Moldovan cargoes depend on the stable operation of the lower part of the river, the Romanian canals and the outlet to the Black Sea. Delays and freight growth in this direction can increase the cost of the country's imports and exports.
For Ukraine, the lower reaches of the Danube are particularly important due to the operation of the ports of Reni, Izmail and Ust-Dunaysk. The critically low depth already limits the normal loading of barges and delays the execution of contracts. The cost of transportation from Reni and Izmail to Constanta has increased to about $28 per ton as of July 20, and individual vessels are losing 30-60% of their carrying capacity.
Continuation of the heat until August 6 will increase evaporation and keep pressure on the water regime of the Danube. Even with localized rain, the improvement is likely to be temporary, as water shortages are forming across the basin, from Germany and Austria to Romania, Moldova and Ukraine.
For shippers, the most likely consequences will be a further reduction in barge loading, the use of more vessels to transport the same volume, rising freight rates, delays in the supply of fuel, grain and industrial raw materials, as well as partial forwarding of goods to railway and road transport.
A significant improvement of the situation is possible only after a long period of rains in the Alps, Germany, Austria, Slovakia and other parts of the basin.
