The Paglia River behaves like a pendulum: give it a push, and instead of accelerating, it swings back. For twenty-two years, scientists recorded how much water passed through the river near the Italian town of Orvieto, every half hour. That yielded 377,399 measurements. They calculated how neighboring fluctuations were related and saw that after a large surge, the river quickly returns to its normal level.

Over time, the variations in this exponent revealed rhythms with periods of about 12, 6, 3, and 2.5 days. These resemble cycles of large-scale ocean and atmospheric phenomena, such as El Niño and the North Atlantic Oscillation. It seems that the distant ocean influences the river, which responds with its own fluctuations. The scientists also checked how often leading digits appear in the data and found an anomaly: some values repeat too frequently. This happens because water levels were measured to the nearest centimeter and then converted to discharge using a single formula. As a result, the records contain "steps." Such checks help assess flood risks and verify the reliability of measurements at hydrological stations.