The water level at a key waypoint on the Rhine River is forecast to stay extremely low for the rest of the week, signaling the continuation of severe restrictions for shipments of vital commodities along Europe’s most important waterway.

The marker at Kaub, a shallow point on the river west of Frankfurt, is currently at 31 centimeters (12.2 inches) and expected to remain in a range of 31-34 centimeters into Saturday morning local time, according to the latest government data. When the water-level drops to 40 centimeters or below, it becomes uneconomical for many barges hauling commodities to sail through the chokepoint.

The Rhine is used to transport millions of tons of fuel and other goods. Low water levels restrict how much cargo the barges that traverse the waterway can carry. The marker at Kaub is not the actual depth of the river, but a measure used for navigability. Rainfall is expected to increase in Germany in the coming days.

Companies that do business along the Rhine have been taking steps to prepare for low water levels, including stockpiling coal and relying more on rail. Some shipping firms have restricted their activities.