Durance (II / III / IV)

The rock through which the tunnel has been cut is a quartzite, a metamorphic, siliceous rock which is very hard and formed by grains of quartz welded together. It originates from sand deposited 230 million years ago in the still-shallow waters of the nascent Alpine ocean, and brought here by the erosion of the surrounding topography. In places, undulations can be seen on the tunnel wall: these are ripple marks, "fossilised" creased created by water flowing over the sand. 

Protected from Atlantic influences by the Massif du Pelvoux, the high Durance valley has a very dry climate with wide seasonal temperature fluctuations. It has grasslands very similar to the steppes of Central Europe which are rare in France. It is part of the Natura 2000 “Steppique durancien et queyrassien” (Durance and Queras valley steppes) site.

The Sentier du Gouffre has sometimes been described as a Roman road, but we do not know the exact route the Roman road followed. One thing is certain, it used to be used by the villagers to reach their fields and vineyards, and for any other journeys they had to make.

In ancient times, the Durance valley was a key communication corridor. Rama was a kind of staging post on the Roman road. In the Middle Ages, Rama was a small town with a noble's château. But the village was devastated by the capriciousness of the Durance and the Biaysse rivers on numerous occasions and the inhabitants gradually deserted the site, moving to neighbouring villages. The attachment of the parish of Rame to that of La Roche in 1446 is indicative of this decline.

The alpine anemone or the alpine pulsatilla blooms here in the spring. It is a plant with a downy covering of white hairs on the large drooping flowers which are dark purple, contrasting with the bright yellow of the numerous stamens, and with very indented leaves. In summer, its fruits with a long pappus, or tuft, form a feathery seed head atop the stem. Although it is frequently found in localised areas, it is nevertheless a rare species dependent on steppe meadows in the Durance valley.

A small resident passerine with a black cap, brown back and white underside, the willow or alpine tit lives in the mountain forests. It selects a trunk with rotten wood in which to built its nest, because its beak is not designed for pecking into very solid trunks. This tit is very similar to the marsh tit, which tends to live below 1,400 metres. To distinguish between them, you have to listen carefully to the singing and calls of these two birds.

In 1910, a 22-year-old engineer, Gilbert Planche arrived in L'Argentière-La Bessée to take advantage of the water here and open a large aluminium factory.

The vertical compressor is the forerunner of the pneumatic drill. The mine operators needed a large quantity of coal and compressed air helped to accelerate coal output. In 1852, Swiss physicist Jean-Daniel Colladon invented the pneumatic drill. The vertical compressor enabled the production of compressed air which powered a drill and simplified coal excavation. The compressor is placed vertically on its support, hence its name. 

Louis Leprince-Ringuet was the director of the Physics Laboratory of X ("X" being a polytechnic school in Villeurbanne) established in L'Argentière. During the summer of 1942, he took in several Jewish students, thus saving them from the Nazis and deportation to Auschwitz. A panel presents the discoveries made by Louis Leprince-Ringuet in this laboratory. A text by Bernard Lévi is also displayed. As a young Jewish student, he took part in research at the laboratory during the summer of 1942. In it he thanks the scientific team for helping him to escape the anti-Semitic barbarism.

This French electro metal company established itself in L'Argentière in 1907. The construction of the aluminium factory started in 1909 and it opened its doors in 1910, powered by the electricity plant built by Gilbert Planche. With it, L'Argentière became an industrial town. The economic crisis of the 1970s and the rise of foreign sources of supply led to the factory's closure in 1985. It was partially demolished in 1988. The workers left the town and in order to prevent the abandonment of L'Argentière, a restructuring project was launched. 

The American James Francis developed the Francis turbine between 1849 and 1855. It is a “àreaction” turbine suitable for medium-sized waterfalls (with a water head of between 15 and 500 metres). The water enters the turbine and then circulates between the turbine blades, which are fixed, while the inner wheel is mobile. The pressure at the wheel intake is greater than the pressure at the outlet. 

Filled with materials excavated from the mine face, the rail-cars were pushed along the rails by the miners.  

They were called “mine dogs”. They were originally made from wood and over time iron pieces were added. They were made entirely from metal by the end of the nineteenth century. 

In the mines, compressed air is used to remove dust and to create power for the drills. The mobile compressor holds compressed air in a resistant tank. This is brought to a high pressure via a pump (the compressor). The compressed air is then distributed to the mine machinery through a conduit system.

A young metal, aluminium is the most abundant metallic element on earth. Today, the aluminium industry is the second biggest after steel. 

This enormous ingot was made in L'Argentière-La Bessée. 

A locomotive? No, its little cousin, the light rail tractor. This replaced manually pushed carts and horse-drawn vehicles. Less powerful than a locomotive, it travelled along narrow-gauge tracks which could be laid on different types of terrain. An information panel also described the role of this vehicle during the Great War.

The mountains are areas naturally used for agriculture. These agricultural practices have been carefully thought-out in order to protect the environment. Agri-environmental measures have been introduced. They are designed to encourage and remunerate volunteer users of mountain spaces in their actions to protect natural environments. These measures prevent over-grazing, the invasion of bushes and shrubs and the proliferation of invasive plants. 

Straw can be used as an insulation material. In fact, it can even be used in its natural state to insulate walls. Straw is available everywhere, it is an abundant resource and its production creates no pollution so it makes a very eco-friendly material. In addition, it offers excellent sound insulation.

Adoux are water courses in which fish can rest, breed and grow within a remarkable ecological reservoir. An ecological reservoir is an area which contains all the natural habitats necessary for the life cycle of a species: from reproduction to feeding and growth. So it could be said that an ecological reservoir assures the survival of the species and fulfils the function of a breeding ground. 

This former school has acquired a new function: that of giving new life to obsolete furniture and objects. The Resourcerie reclamation and repurposing centre makes new objects out of other, unwanted items. No new raw materials are used in their production, thereby helping to prevent the accumulation of waste. Eco-friendly and sustainable, the reclamation and repurposing centre reduces waste and creates employment. 

The symbol of the Southern Alps, this softwood tree loses its leaves in winter, and is swathed with gold and lights up the mountains in autumn. The larch forests are maintained by the grazing of flocks. Without them, other trees like the fir or other pine trees could grow, creating a different kind of forest. A pioneer species, the larch establishes freely in light conditions. Its solid rot-proof wood has always been used in the construction of houses.

On this path, you will pass by some eco-constructed cabins. One of them is made from larch, a wood that is naturally resistant to bad weather and insects and needs no previous treatment. The other is constructed according to the “post-beam” principle, which is reminiscent of half-timbered construction. This is characterised by an exposed supporting framework. The beams support the roof, and these beams are in turn are supported by the posts. 

Workers' housing districts were built to house the many workers who were employed at the Péchiney factory. These districts have now been demolished. The architecture of the houses varied according to the status of the employee. A town hall, a cinema, a bandstand and churches were also constructed. 

The school in Saint-Martin-de-Queyrières is built out of materials that are safe and sustainable. The building is of bioclimatic design, that is to say, the architecture is adapted to the characteristics of the climate of the local area in which it is sited, in order to obtain the most natural ambient comfort possible. The environment provides power and resources through, for example, the capture of solar energy, the use of air circulation techniques, rainwater harvesting etc.

The municipality of L'Argentière owes its name to the silver mines exploited here. They were first worked in the early Medieval period and later abandoned before exploitation resumed again in the nineteenth century. They were finally closed in 1908. Since 1992, the site has been the subject of archaeological excavations, with major work to clear materials carried by the Fournel when in flood. They can be visited with a guide (by appointment), leaving the visitor in awe: how much ingenuity has been involved in extracting the silver-bearing galena! 

The Tour des Hermes is a clock tower built in 1922 by the Gilbert Planche company which used to run the aluminium factory in L'Argentière. It would chime to remind the factory workers of the time, and to make sure they arrived for work on time!

In 1910, a 22-year-old engineer, Gilbert Planche arrived in L'Argentière-La Bessée to take advantage of the water here and open a large aluminium factory. Many workers were employed and workers' housing estates were built (now demolished). As the result of financial problems, the factories closed its doors in 1985 and the area gradually emptied. Today, derelict sites bear testimony to the town's industrial past.

Built in the twelfth century and listed as a Historical Monument, the chapel of Saint-Jean is of Romanesque style. Tombs cut into the rock were discovered in recent archaeological excavations. 

The sundial is an eighteenth-century tradition widespread across the Southern Alps where the sun is ever-present. Artisan sundial makers produced these sundials, which were added as a decoration to house fronts, religious buildings or, as here, a tower. The sayings inscribed on them make some of these artistic works philosophical as well as decorative. 

Protected from Atlantic influences by the Pelvoux massif, the upper Durance valley is subject to a very dry climate, with wide seasonal temperature fluctuations. It features grasslands very similar to the steppes of Central Europe, and which are rare in France. It is part of the Natura 2000 site, “Steppique durancien et queyrassien”.

The source of the Fournel rises in the Fournel valley, in the heart of the Parc National des Écrins, and flows into the Durance near the white water stadium. It is known as a high alpine canyon offering lots of sport and leisure possibilities, and is the most popular in the Haut Val Durance. It is ideal for an introduction to vertical activities, in particular thanks to the presence of several jumps, toboggan runs and rappel sites. Access is authorised from April to October and is regulated because it is located upstream from an EDF water intake, which presents a real hazard.

It was in the late nineteenth and early twentieth century that hydropower really came into its own in L'Argentière-la-Bessée. There was plenty of water flowing from the mountains here to generate electricity, at a time when electricity transmission - let alone diversion - technology had not yet been developed. This was achieved by digging out a number of tunnels and laying penstock pipes. Aluminium production became possible and so, too, did a fused quartz activity, making specialised glass for the chemicals industry.

A bird of prey circles slowly above the valley. It is dark coloured with a slightly forked tail. A black kite, which returned from Africa in spring. It feeds on carrion or scraps as well as fish. It is easy to confuse with the red kite which is brown, red and white and its tail has a much more pronounced fork. The red kite does not nest here in the massif. It is only seen during the migration period, in the Durance valley.