The Dry River: Water Depth Is the Input Nobody Prices
The Rhine at Kaub fell to 25 cm — the lowest since 2018 — and barge freight to southern Germany rose ~400% in two months. A river is infrastructure, and it stopped working.
What changed
The gauge at Kaub — the Rhine's narrowest commercial point — fell to 25 cm, the lowest since 2018. Below roughly 40–50 cm a barge may legally carry only ~20% of a normal load (German Federal Waterways & Shipping Administration). Benchmark barge freight from Rotterdam to points south of Kaub rose roughly 400% in two months, and riverside industrial operators began flagging production-interruption risk.
The mechanism
Rain doesn't fall → the river drops → the barge carries a fifth → freight quadruples → the factory waits → the cost arrives in the finished good. Nothing has to happen for this to continue: a drought is a condition, not an event. There is no announcement to react to and no counterparty to blame.
Why it matters
Water depth is not a traded input. It appears in no commodity book and most supply-chain models treat inland waterways as fixed capacity. They are weather. The exposure is real, measurable in centimetres, and almost universally assumed away.
Markets price the barrel. Nobody prices the riverbed.