Dry weather in early June meant the river became too shallow and vessel operators imposed surcharges on freight rates to compensate for vessels sailing partly empty, increasing costs for cargo owners.

A downpour last week meant southern and central sections of the river were now around normal levels allowing vessels to sail with normal loads, commodity traders said. Vessels can sail with full loads in the southern sectors of the river to Switzerland.

The chokepoint at Kaub is only 1 cm below the level allowing full vessel loadings.

But the Rhine is still too shallow for normal sailing in the northern areas around Cologne and Duisburg.

Dry weather this week could lead to water levels falling again, the German navigation authority WSV forecast. Rain is only predicted again in the southern river catchment areas on Friday.

The Rhine is an important shipping route for commodities such as grains, minerals, ores, coal and oil products, including heating oil.

German companies faced supply bottlenecks and production problems in summer 2022 after a drought and heat wave led to unusually low water levels on the Rhine.

(Reporting by Michael Hogan, editing by Sohini Goswami)