The unusually low water levels in the River Danube in Hungary are causing problems for shipping, agriculture, and local ecosystems along Europe’s second-largest river, an important transport route for the entire continent.

Temperatures have even reached as high as 35 degrees Celsius in Budapest this week, as much of Europe experiences a wave of persistent heat linked to the deaths of at least eight people.

As a result of low water levels, cargo ships are forced to carry less than half of their cargo and can only operate at 30-40% capacity, said Atila Bencik, vice-president of the Hungarian Shipping Association.

Tariffs may increase up to 100%, as there is a surcharge when a ship cannot sail fully loaded, he said.

Such water levels have been recorded on the Danube before, but it usually happens in August, said Atila Szegi, a deputy spokesman for the Hungarian general water management directorate.

He said rain is expected next week in the Danube basin, which should lead to a slight increase in water levels and an improvement in the navigation situation.

The Hungarian state weather institute HungaroMet reported that rainfall in June was only 17% of the average for the month, making this June the driest since 1901.

“June is one of the rainiest months of the year in our climate, and now we have this low water level,” said Gyorgy Matavowski as he stopped his kayak on a sandy bank in Sob, a town north of Budapest. “It has its beauty because the water is clear, it’s easy to paddle … but it’s unsettling.”

The level of the Vistula River is also at a historic low in Warsaw, and the level on the Rhine in Germany is also at an unusually low level.

Michal Sikora, a meteorologist and hydrologist at IMGW in Poland, said the Vistula River reached a historic low of 19 centimetres today, adding that it is expected to drop further in the coming days, possibly below 15 centimetres.