Rhythmic spring

[1] Although the cause of the periodicity in flow is not known for certain, the most accepted theory (first postulated in the early 18th century) is that as groundwater flows continuously into a cavern, it fills a narrow tube that leads upwards from near the base of the cavern, then downwards to the spring.

[2] In 2006 the University of Utah studied the Intermittent Spring in Swift Creek canyon in Star Valley, Wyoming, United States.

Kip Solomon, a hydrologist at the University concluded that "The spring water's gas content has now been tested [...].

The Gihon Spring in the City of David in Jerusalem used to be a rhythmic spring before modern-time overpumping affected the level of the underground water table.

It was of great historical, archaeological, and cultural importance because it is what made possible the human settlement in ancient Jerusalem.