A ride in the Bourg d'Oisans plain

Rochetaillée lierally means "cut rock" in French and looking up at the road carved out of the cliff face, it is clear how the village got its name. However, the exact origin of this road appears lost in the folds of history.Is this road, as many people believe, the remains of a Roman road, the indelible mark of an unstoppable sovereign population? Or, as Doctor Roussillon suggests in his Traveller's guide to Oisans, is it "the still visible trace of a path created during the existence of the lake, along the bottom of the neighbouring mountain and behind the small hamlet of Rochetaillée, from which it draws its name. Such were the circumstances in which this path was built." An observor at the end of the 19th century reported certain similarities beween the Porte des Bons and the Rochetaillée road, suggesting a close correlation between the two. Marks and tracks on the ground were reported to be similar and of exact equal width. Unfortunately, no trace of these marks has been found since and the campaign to clear and clean the site carried out by in 2004 by "Customs and Traditions of Oisans" also failed to uncover any evidence. To better understand this, it needs to be remembered that in the last century, the plain through which the road passes was like a desert without any vegetation. Both the cliff and the plain were completely bare, meaning that it was no doubt easy at the time for witnesses to observe and note the smallest details. These days, the road is virtually covered by vegetation and in some places, you can almost walk past without noticing it. But why carve the road out of the rock? If we go along with Docteur Roussillon's theory, the creation of Saint-Laurent lake would be the only tangible reason for this project, which must have involved considerable manpower and resources. The other theory, if we consider this to be a Roman road, suggests that any rapid progress towards the high mountain passes was hindered by the neighbouring plain. Perhaps it was a swamp or a lake that was liable to flooding due to the unpredictable behaviour of the Romanche river? The size of the project to build the road would also prove the importance of the "Oisans way" in the eyes of the Romans. Along the entire length of the platform, rectangular markings are carved out of the stone at regular intervals. These suggest that a structure consisting of beams and a wooden floor covered the road, widening it from 2 metres to 3 or 4 metres and making for easier progression. At suitable points, wider platforms were installed, known as "garages" that served as passing places for animals and carts. To this day, the track linking Rochetaillée to Bourg d'Oisans, via the hamlets of La Paute and Les Sables, is known as the "Chemin Romain". Source: Freneyd'Oisans.com/Mr Albertino

The Bourg d'Oisans plain was hollowed out over the centuries by glaciers, before being filled by sediment from rivers that formed a lake, called the Lac St-Laurent. On several occasions over a very long period, this wide valley has been a lake.The Bourg d'Oisans basin is characteristic of the erosion and accumulation that occurred at the end of the tertiary and quaternary eras due to the glacial waters that dissected the mountainous mass, reducing it to a network of crests. The successive lakes and deposits of rivers filled the valley with sediment, but the glacial rock bar was backed up by another rock bar formed by two alluvial cones from mountain streams opposite the current Pont de la Véna bridge (just outside Livet on the way to Grenoble). Upstream, the Romananche river formed a lake, the Lac St-Laurent, which was regularly emptied. Bourg d'Oisans was then called Saint-Laurent du Lac. Prior to 1091, it is difficult to pinpoint an exact date as to when the lake was formed, although mentions of it have been found in documents dated 1058. In 1191, the Infernet was the scene of a terrible drama, when a substantial rock fall and landslide completrly blocked the flow of the Romanche, creating an insurmountable barrier. This caused the lake to spread to over 18 km in length, submerging the plain under 10 m of water. St Laurent du bord du Lac completely disappeared under the water and all the local inhabitants had to flee their homes, seeking safety on higher ground. According to some documents, the water rose to a level of 741 m above sea level. 28 years later, on 14 September 1219, the dam suddenly burst, creating a catastrophic flood that reached as far as Grenoble (known as the "Flood of Grenoble") killing some 5,000 people. The natural dam had given way under the sheer weight of the water and an enormous volume of water rushed into the gorge with the violence of a hurricane, sweeping away everything in its path, whether trees, fields or whole villages... Although smaller in size, the lake continue to exist for another three centuries, sometimes increasing in volume, as on 4 August 1465 after a terrible summer storm. In 1429, it was recorded that the lake had dried up, only to return at a later date. In 1540, reduced to a "puddle", it finally disappeared... Over the following centuries, the Romanche wended its way through the plain, causing regular floods. In the 18th century, dykes were built to contain the river and the plane was drained using the grid system that now makes for an original landscape. Once the plain had been restored, plans were made to clean it up and grow crops. Back in the 13th century, just after the 1219 catastrophe, the village of St Laurent became the centre of interest for all the local population and villages. The tantrums of the Romanche were only contained once and for all in 1935, with the construction of the Chambon Dam. Website: bourgdoisans.com / freneydoisans.com