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

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

Rain in the past few days has raised water to normal levels in some southern sections of the river, commodity traders said.

But the Rhine is still too shallow for normal sailings at the choke point of Kaub and northern areas around Cologne and Duisburg. Depending on type, some vessels can only sail half full in northern regions, they said.

More rain in river catchment areas is forecast this week which could help shipping, they said.

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 Sonali Paul)