
YSK: when the news says the Rhine has fallen to 16 cm, that is not how deep the river is
The number in those headlines is the reading at the Kaub gauge in Germany, which everyone quotes because it sits on the shallowest stretch of the navigable Rhine. It is a water level measured against a fixed zero point that was set historically, not a measurement of the water column. That zero sits above the riverbed, so the gauge can read very low while there is still a usable channel underneath.
The rough conversion used in German inland shipping is: navigable fairway depth = gauge reading + 1.90 m - 0.78 m. So a gauge reading of 14 cm is a channel about 1.27 m deep, and a reading of 0 cm still leaves roughly a metre of water. In early August 2026 Kaub was reading around 16 to 17 cm, the lowest since records there began in 1880, with an actual navigable depth of about 1.3 m.
The reason it still matters is not that the river vanishes, it is that barges are draught limited. At these levels standard Rhine cargo barges can only load to roughly 20 to 30 percent of capacity, so moving the same coal, grain, chemicals or fuel takes three to four times as many trips. That is what raises freight costs and shows up in industrial supply chains.
Two caveats. The conversion constants depend on which reference year is used for the equivalent water level, so treat the 1.27 m style figures as approximate rather than exact. And every gauge along the river has its own zero point, so readings from different stations are not comparable with each other.
Why YSK: this number gets quoted every drought summer and it reads to most people as "the Rhine is 16 cm deep", which leads either to panic or to dismissing the whole story after seeing photos of ships still sailing. Knowing that the gauge is a reference reading against an old datum, and that the real constraint is how much cargo fits per trip, is the difference between understanding the story and misreading it in both directions.
https://en.wikipedia.org/wiki/Kaub_gauging_station
https://www.insurancejournal.com/news/international/2026/08/12/881099.htm