A river with its arm twisted

Right from the Loire’s early sections, fundamental considerations emerge on both sides of the mountain. From its source, the Loire charts a north-south course. Heading towards the Rhône, and then the Mediterranean. As far as Rieutord. This is where the waters of the Loire suddenly veer westwards – full throttle towards the Atlantic. Local tradition long attributed this radical change in direction to the presence of the impressive Suc de Bauzon volcanic peak, the appearance of which was thus believed to have determined the fate of the river’s course. But such thinking is a little hasty, and overlooks the science!

What does geology tell us? The Loire’s valley was formed in stages, each of which left a bench (or terrace). Now, the last distinct bench dates back 2.5 to 3 million years ago, whereas volcanism in the Ardèche – this is where the Suc de Bauzon comes in – happened 200,000 to 15,000 years ago. QED. But local myths are difficult to shake and often find a particular resonance in human accomplishments. To put it plainly: what the volcano couldn't have done, humans did instead.

Since 1954 and the commissioning of the Montpezat hydropower plant, a significant portion of the young Loire’s waters have been tapped to supply it and generate electricity before being released back into the Fontaulière, a tributary of the River Ardèche, itself a tributary of the Rhône. In 2023, 100 million cubic metres of water (99% of the volume withdrawn) thus ended up in the Mediterranean rather than in the Atlantic! An astonishing thought!
 

The thwarted path of a water droplet.

In the years immediately following the war, reconstruction was the priority. France needed energy and hydropower not only produced a lot of it, but could also be managed. At the highest levels of the State – notwithstanding turbulent discussions at the National Assembly – the green light was given for the plant’s construction.

Almost 14 miles (22 km) of galleries connect 4 reservoirs and dams (Lac d’Issarlès and La Palisse in particular) and culminate in a 638m head as far as the underground plant of Montpezat-sous-Bauzon: a “marvel of engineering”, the concession of which, entrusted to EDF, is due to expire shortly. Except that, in 70 years, the climate and water context has changed considerably: on the one hand, the Loire and the regions it flows through desperately need the diverted water; and on the other, the water ultimately returned to the Ardèche has become indispensable to a region that is becoming increasingly arid and dependent on mass tourism and intensive farming.

What can be done? SOS Loire Vivante, an association long accustomed to fighting for the Loire, has got involved and suggests a discussion focusing on sharing the water - where the aim is not to know whether more water is needed for the Loire or the Ardèche, but to choose between energy and environments. An ontological question, in a symbolic place: the nearby watershed divide gets us thinking about our choices just as much as it sparks our imagination. A water droplet, whether it falls on one side or the other of this divide, should inevitably join up.