HAMBURG (Reuters) - Rain has raised water levels on the Rhine in Germany but most of the river remains too shallow for cargo vessels to sail fully loaded, commodity traders said on Wednesday, following a bout of dry weather in August.

Ship operators imposed surcharges on freight rates to compensate for vessels sailing partly empty, increasing costs for cargo owners.

Shallow water continues to hinder shipping on most of the Rhine in Germany including Duisburg, Cologne and the chokepoint of Kaub, but vessels are able to take on larger loads, traders said.

More rain is forecast in river catchment areas on Wednesday and the coming days and this is expected to raise the river to levels allowing normal shipping later this week or early next week, they said.

The Rhine is an important shipping route for commodities such as grains, minerals, ores, chemicals, 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 river.

But repeated rain earlier this summer had kept Rhine water levels high, enabling shipping to mostly operate normally until late August.

(Reporting by Michael Hogan, editing by Gareth Jones)