River levels are measured continuously at gauge stations along rivers and canals. They are essential for flood warning, navigation, water management, and ecology. Levels are usually expressed relative to each station's own reference datum—for example NAP (Normaal Amsterdams Peil) in the Netherlands, or a local hydrometric zero in Tuscany. Because these reference points differ, levels from different networks are not directly comparable to each other; a rising level generally indicates recent rainfall or snowmelt upstream, while falling levels often follow dry weather or reduced runoff.

Trend (rising, falling, or steady) is derived from recent measurements and helps assess whether the situation is stabilising or changing. In the Netherlands, Rijkswaterstaat operates a dense network of gauges and publishes alarm levels (e.g. alarm 1, 2, 3) for many stations; in Tuscany, the Centro Funzionale Regionale (CFR) publishes official attention and alarm thresholds for its own gauges. When levels approach or exceed these thresholds, the relevant authority may issue warnings or take measures. The data on this page is updated periodically from each active provider's own network.

River flow is influenced by precipitation, snowmelt, soil moisture, and human interventions (dams, locks, drainage). Large rivers can have long response times, while small catchments can rise and fall within hours. The readings here are real-time measurements, not forecasts. For official flood and drought information, always refer to the relevant authority—Rijkswaterstaat and the national crisis and water management authorities in the Netherlands, or the Centro Funzionale Regionale and civil protection authorities in Tuscany.

Did you know? At Lobith, where the Rhine enters the Netherlands, the average discharge is about 2,200 cubic metres per second—roughly one Olympic-sized swimming pool every second—and can exceed 12,000 m³/s during major floods. In Tuscany, the Arno's average discharge near Florence is only a few tens of cubic metres per second, but during the catastrophic flood of 4 November 1966 it was estimated at several thousand cubic metres per second—one of the reasons river monitoring remains so important today.