Urban exploration - The Rhonelle underground river
This page is a short underground excursion through the discharge canal of the Rhonelle, a subterranean river that flows beneath the city of Valenciennes.
According to fairly consistent reports on the matter, the construction of the structure dates back to the very beginning of the 20th century. Given the great uniformity of the work, this tunnel must have been built in a single phase. It is a gallery in very good general condition, equipped with a *cunette* (a central drainage channel). As a result, the visit is easy. Various small streams connect to it, but they are generally overwhelmed by (hydrogen sulfide). The end of the gallery is a thundering waterfall. This is the Rhonelle itself, discharging its overflow. The location is remarkably aesthetic, though not open to visitors as any further investigation would become dangerous.
At a point where the tunnel forms a very wide curve, a concrete passage catches the eye. Unconventional in appearance, it looks like a secret passage that was hastily reinforced. Behind this makeshift access point, that impression is confirmed. A short excavation into the chalk, almost anarchic in nature, is reminiscent of the quarries in the Mons Plain. This small gallery leads immediately to a "fossil" of a fortification. I say fossil, or relic, because the remains are incomplete. These galleries have been largely severed by the various redevelopments of the city. It is a remnant of the Vauban fortifications of Valenciennes.
The fortification is located beneath the Lycée Watteau. The galleries form a very wide V-shaped plan with a few side branches. There must have been a much larger network at the time, but this is all that remains—at least here. The galleries themselves are not particularly curious; being linear, they offer only a limited number of surprises, as is typical of any Vauban fortification. On the other hand, beautiful blue stone staircases allow you to climb one floor, or even two if you reach the surface in an annex of the high school.
And that is where the magic of Valenciennes happens. After traveling through an underground river that joins antediluvian sewers and channeled streams, and after crossing a Vauban fortification, you suddenly arrive in two beautiful, vast rooms. These might have once been the high school cellars (though they are somewhat eccentric in location). For a moment, and only a few meters away, one could almost connect with the underground voids of the "Water Tower" quarry, which is further bordered by large underground drinking water reservoirs. That is Valenciennes: a remarkable secret world buried beneath your feet.
We were already exploring these basements back in 1998, which shows just how long this history goes back. Rue Milhomme, le Glacis, Fort Minique, rue Fleurie—we were there, and it was wonderful! Today, most of these quarries virtually no longer exist. The danger of the sites led to them being filled in. It is a great loss from a historical perspective, but the necessity is understandable.
The two rooms in question are fairly well-preserved despite major humidity issues. The brick walls have been painted. Countless visitors have left a small memento of their passage. Many have become illegible. The oldest date back to 1882–1887 and seem to be concentrated in that period. During the First World War, works from the Museum of Fine Arts were hidden in these premises. The two rooms are located under Boulevard Pater. Despite the car traffic above, this location is absolutely undetectable on-site. Nothing specific can be heard.
The underground Rhonelle was not accessible during my visit, as there were two meters of water at the time. Several attempts made at the entrances of the underground "Vieil Escaut" (Old Scheldt) yielded no better results. On both sides, I had to face a "methane power plant." The mud bubbled with every step. Within the very confined environment (which was at the limit of what is possible), it was becoming dangerous. Something to do another time, though without much optimism.
Nonetheless, it still makes for a beautiful walk. Here is a short audio report and some photographs.
