The Doubs river has changed color, Thursday, July 30. In Besançon, the river which bathes the capital of the franche-comte region has become... green neon. The fault with a dye, fluorescein, harmless to aquatic fauna, dumped by hydrogeologists to better understand the hydrographic system, reports France 3 Bourgogne-Franche-Comté. In effect, a cavity was discovered in a district of Besançon, where a new eco-development is to see the light of day. Wide and deep two meters, it would no doubt be old of two million years. The scientists realized that the cavity to a depth of at least 15 meters of depth in the direction of the Doubs.

A trip of 30 hours

It was therefore decided to pour into the cave this dye. And it took 30 hours to reach the river. According to The Is a Republican, the dye is pulled by two small tuyaus PVC, posed in previous work on the inside of a cavity, which borders the river Doubs. "Inside of these pipes, we found the presence of shells. This confirms the idea that we are on a natural system, with clean water, " says hydrogeologist Pascal Reilé, which estimates that the discovered network is very old.

also Read United States : discovery of a water reservoir "virgin" of any human contact

Now the hydrogeologists will try to see if the dye appears in a different place. Know the hydrographic network could be made use of, indicates the local television channel. In fact, this cave could, in the context of the future district, to be used as evacuation of rainwater. But for this, it is necessary to determine if this cavity interferes with the drinking water network and whether it has the capacity to receive a lot of water. In the meantime, the Doubs region of france should stay neon green for a few days, his flow is currently low.