FRANCE'S BIGGEST KARST SPRING
The Fontaine de Vaucluse, the source of the River Sorgue, is the biggest karst spring in mainland France. It's the fifth biggest in the world with an annual output of
630-700 million cubic metres of water. It has set a benchmark in hydrogeology, with the term "vauclusian spring" used to describe a specific type of karstic spring.
The spring is the sole outlet for an underground lagoon that forms a 1200km2 impluvium collecting water from Mont Ventoux, Monts de Vaucluse, Plateau d’Albion and Montagne de Lure.
The cave is deeper than the cliff is high: the cliff is 230m high and the cave is 315m deep.
EXPLORING THE CAVE
From the late 19th century onwards and after major caving expeditions in the 20th century, we learnt that the cave is not a spring but is actually an outlet for a gigantic underground river.
The Fontaine-de-Vaucluse caving society sent a robot down in 1985 to the lowest known point to date: 315m deep. The spring runs into 2 galleries that have yet to be explored.
A scale was carved into the cave rock in 1869: it's called the "sorgomètre". It measures the water level inside the cave.
EXPLORING THE CAVE
From the late 19th century onwards and after major caving expeditions in the 20th century, we learnt that the cave is not a spring but is actually an outlet for a gigantic underground river.
The Fontaine-de-Vaucluse caving society sent a robot down in 1985 to the lowest known point to date: 315m deep. The spring runs into 2 galleries that have yet to be explored.
A scale was carved into the cave rock in 1869: it's called the "sorgomètre". It measures the water level inside the cave.
FLOODING THE CAVE
When the water reaches the 21.07m mark on the "sorgomètre", the fountain overflows above the threshold before running into water from smaller springs (known as "griffons") further downstream.
What sets the Sorgue apart is its output and average year-round temperature of 13C°.
WHERE DOES THE WATER IN THE CAVE COME FROM?
Fontaine de Vaucluse Impluvium diagram Fontaine de Vaucluse Impluvium Vaucluse Département
HOW DEEP IS THE CAVE?
Fontaine de Vaucluse Cave cross-section
WARNING UNSTABLE CLIFF / RISK OF FALLING ROCKS NO ENTRY BEYOND 50M
Traffic regulation ref. AP 2024-0017 DISR Regarding the Chemin de la Fontaine track
Fontaine-de-Vaucluse Council