Fifteen gauges along the Danube, and between them the river in the colour of its level: violet low, blue normal, red high.
Reading the colour
The colour is not a verdict but a placement between known marks — low water, mean water, high water. Between two gauges it is computed, not guessed.
A stretch no gauge reaches stays grey and dashed. That means nothing is known about it — not that nothing is happening there.
A gauge reading is not the depth of the water. It is a height on a measuring staff, and what it means only becomes clear from the distance to mean water shown beside it.
Now, before and after
Tap or hover a gauge and its card appears right there; a click makes it stay. Above the map stands the gauge nearest to you.
At the top you see when the data were last fetched and how old the newest reading is. Once that passes an hour it turns red and reads "stale" — better a visible gap than a number that looks current and is not.
Where the numbers come from
The data come from the official measuring stations, fetched every five minutes and only displayed here. The credit lines under the map — ehyd.gv.at, via donau, GeoSphere and the note on the river geometry — are licence conditions, not decoration. They have to stay.
Below the gauge card sits the rowing light with the club’s limits, and under that the wind on the river. All without warranty: what you read here does not replace a look at the water.