The Rhine is too shallow for normal sailings around Cologne, traders said. All of the German section of the Danube is too shallow for full loads, they said.
Shallow water means vessel operators impose surcharges on freight rates, increasing costs for cargo owners.
The Rhine is an important shipping route for commodities including grains, minerals, coal and oil products including heating oil. The Danube is a major route for east European grain exports to western Europe.
Reporting by Michael Hogan