Kaub’s six-centimetre gauge chokes 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 officially closed. It does not need to be. When the water drops this low, ships must ride higher to clear the riverbed, so they carry a fraction of their normal load. Commercial capacity collapses before any authority shuts navigation down, and the extra costs are already showing up in French petrol stations, German chemical plants and Belgian building sites.

Six centimetres at the chokepoint

Kaub, a narrow stretch between Koblenz and Mainz, is the shallowest point controlling traffic between the North Sea ports and the Upper Rhine. Its gauge hit six centimetres on 14 August and broke that record the next morning (Tagesschau, nrw-lokal). A gauge reading is not the literal depth of the river; it measures against a fixed reference point, and vessels can still pass when it shows single digits (n-tv). But they pass nearly empty.

Barges are running at roughly 15–35% of normal payload (Reuters/WSAU). For western Europe's industry, the Rhine is the main conveyor belt: about 300 million tonnes of cargo a year in chemicals, fuel, steel, grain and construction materials (CCNR). When each trip carries a quarter of its usual load, everything that moves on the river costs more per tonne. A barge that once delivered 2,400 tonnes of diesel now brings a few hundred. Surcharges compound with every trip.

Where the costs land

The disruption hit eastern France first. Petrol normally arrives in Alsace by barge from northern European ports, and that supply line is now cut off by low water upstream of Strasbourg. On 14 August, 14% of Grand Est petrol stations reported supply problems, with about a third of Alsatian stations lacking at least one fuel grade (Boursorama, TF1). French authorities responded by letting heavy tanker trucks run over the 15 August holiday weekend to resupply from depots further west (Le Parisien).

The price of moving fuel by barge has roughly tripled on the Rotterdam-to-Karlsruhe route since late June. Surcharges are cited at 150–215 euros per tonne by mid-August, 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 practice, that means the company is telling customers it may not be able to deliver because the river can no longer bring raw materials reliably (C&EN, Insurance Journal).

In Belgium, construction firms face low-water surcharges of €8–17 per tonne on sand and gravel, with barges making four trips to carry what used to fit in one (GVA). The Netherlands absorbs less damage because it sits closer to the sea, with more coastal waterway alternatives. Rotterdam reported Rhine-bound volume more than 10% below normal, with vessels loaded at 30–35% instead of the usual 70% (WNL), but ING economist Rico Luman argued Dutch firms can reroute through those alternatives before the shallow middle Rhine becomes binding (BusinessWise).

Every fallback has its own bottleneck

DB Cargo said it could make 900 freight wagons available, enough on paper to replace about 200 inland vessels (Tagesschau, Zeit). That is a planning figure, not delivered capacity. Rail works are already constraining a key Rhine corridor (Kuehne+Nagel), and road is no easier: 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). These flat-bottomed barges can handle shallow stretches, but a dozen of them cannot substitute for a national waterway.

The Kiel Institute estimated that 30 days of Rhine low water is associated with roughly a 1% fall in German industrial production (DW). In an economy already near stagnation, that is not a rounding error. Rail and road can absorb some priority cargo, but they cannot replace 300 million tonnes a year of cheap bulk freight. The Rhine corridor has less backup built into it than Europe's industrial planning assumes.