Kaub gauge throttles Rhine freight

A cargo vessel passed Kaub this week carrying about 180 tonnes of freight. It was built for 1,200 (Argus). The Rhine has not been formally closed, but at this level the distinction is almost academic. Ships must sit higher in the water to avoid the riverbed, which means they carry a fraction of their normal load. Capacity disappears before any official ban is issued, and the cost is already turning up in French petrol stations, German chemical plants and Belgian building sites.

Six centimetres at the chokepoint

Kaub, the narrow stretch between Koblenz and Mainz, is the shallow point that decides how much freight can move between the North Sea ports and the Upper Rhine. Its gauge fell to six centimetres on 14 August and dropped below that the following morning (Tagesschau, nrw-lokal). The gauge is not the river's literal depth; it is measured against a fixed reference point, so vessels can still pass even when the reading is in single digits (n-tv). They just pass close to empty.

Barges are running at roughly 15-35% of normal payload (Reuters/WSAU). For western Europe, the Rhine is an industrial conveyor belt, carrying about 300 million tonnes of cargo a year in chemicals, fuel, steel, grain and construction materials (CCNR). When a trip carries a quarter of its usual load, the price per tonne rises quickly. A barge that once brought 2,400 tonnes of diesel now brings a few hundred. Each extra journey adds another surcharge.

Where the costs land

Eastern France felt it first. Petrol for Alsace usually comes by barge from northern European ports, but low water upstream of Strasbourg has broken that supply line. On 14 August, 14% of Grand Est petrol stations reported supply problems, and about a third of stations in Alsace were missing at least one fuel grade (Boursorama, TF1). French authorities responded by allowing heavy tanker trucks to operate over the 15 August holiday weekend, drawing fuel from depots further west (Le Parisien).

The cost of moving fuel by barge on the Rotterdam-to-Karlsruhe route has roughly tripled since late June. By mid-August, surcharges were being cited at 150-215 euros per tonne, depending on the source (RFI, France24). BASF, whose Ludwigshafen complex receives 75% of its European raw materials by water, has issued force-majeure notices on some product lines. In plain terms, it is warning customers that it may not be able to deliver because the river can no longer bring in raw materials reliably (C&EN, Insurance Journal).

In Belgium, construction firms are facing low-water surcharges of €8-17 per tonne on sand and gravel, with barges making four trips to move what once fitted into one (GVA). The Netherlands is taking less of the hit because it sits closer to the sea and has more coastal waterway alternatives. Rotterdam reported Rhine-bound volume more than 10% below normal, with vessels loaded at 30-35% rather than the usual 70% (WNL), but ING economist Rico Luman argued Dutch firms can reroute through those alternatives before the shallow middle Rhine becomes the binding constraint (BusinessWise).

Every fallback has its own bottleneck

DB Cargo said it could provide 900 freight wagons, enough on paper to replace about 200 inland vessels (Tagesschau, Zeit). That is a planning number rather than capacity already delivered. Rail works are already restricting a key Rhine corridor (Kuehne+Nagel), and road has its own arithmetic: replacing one full diesel barge takes roughly 89 tanker trucks (ingenieur.de). Germany has about twelve dedicated low-water vessels in its entire fleet (ZDFheute). Flat-bottomed barges can manage shallow stretches, but a dozen cannot stand in for a national waterway.

The Kiel Institute has estimated that 30 days of low water on the Rhine is associated with roughly a 1% fall in German industrial production (DW). For an economy already close to stagnation, that matters. Rail and road can take some urgent cargo, but they cannot replace 300 million tonnes a year of cheap bulk freight. The Rhine corridor has less spare capacity than Europe's industrial planners would like to believe.