Isere.fr

This group of molassic hills covered by glacial formations is a crossroads that spreads out around the confluence of the Guiers and the Rhône. It is the point of intersection of the three départements of Ain, Savoie and Isère, and is crossed by three important national highways and the Lyon-Chambéry motorway.

As there is no single point of convergence, these different throughways have favoured the emergence of several secondary towns, including Tour-du-Pin, les Abrets, Aoste, Pont-de-Beauvoisin.

The very beautiful architecture of Corbelin's public buildings, grouped around the high street, make it a remarkable village. But mounting real estate pressure is raising the risk of diffuse urbanisation throughout the surrounding landscape. This is the case in particular of the Bourbre Valley above Tour-du-Pin. Unlike the Virieu Valley, this valley is very populated and marked by single-family homes and groups of small businesses. After Marlieu, there is the plateau with its patchwork patterns of diffuse urbanisation.

This type of urbanisation affects many of the alluvial plains and plateaux of the hill vegetation stage of the Dauphiné foreland, in particular the plains of East Lyon and of Chonas l'Amballan , the Bonnevaux Plateau , the Saint-Jean-de-Bournay Plateau , as well as the southern part of the Saint-Marcellin Plain . This, along with the urban sprawl onto the hillsides and linear urbanisation, represents one of the effects of the rurbanisation of the area.

This is characterised by the development in rural communes of daily commutes to the cities at distances of 30 to 40 kilometres, thus extending beyond the suburban belts characteristic of the post-war boom years. This phenomenon spread from 1975, the start of the urban exodus that followed a rural exodus throughout the country. It went hand in hand with an influx of retirees and the creation of new jobs in the countryside, as well as the boom in tourism in the mid-level mountains, and represented the peak of the generalised periurbanisation that made Isère one of the French departments where urban integration went the furthest (Charrier).

This rurburnisation was based on technological, economic and cultural advances in the cities that spread largely into the countryside, beginning with the car and the unprecedented mobility that it made possible. Suddenly it seemed that the countryside offered additional advantages that made it a desirable destination. One of the strongest motivations for moving to the countryside was the possibility of acquiring a house which contrasted with the high cost of housing in the city, particularly of single-family homes. This was also fuelled by the development of universal car ownership , then two-car families, as the time spent everyday in town-to-country trips was sometimes less than town-to-suburb commutes, without even taking into account the difficulty of parking. A third reason frequently invoked to explain the success of the countryside is the attractiveness of lifestyles that could be described as ecological in non-polluted, calm and verdant settings.

One frequent consequence of all this was diffuse urbanisation. This is characterised by patterns of isolated construction or small clumps of buildings separated by a few hundred metres or more in layers of differing extents. The first impact of this is to blur the legibility of the landscape by multiplying the focal points on spaces that should only have two or three such points. Any building, even a simple farm, is in fact a focal point on a landscape, which presumes that it is surrounded by motifs that march in step with it in the landscape heritage scheme. The multiplication of focal points diverts and disperses the attention of the observer, whose gaze wanders from one point to another without ever settling on a small number of essential features, and who winds up giving up.

In principle this type of urbanisation is no longer possible. This should strengthen a landscape approach and analysis that seeks out potential forms of grouped habitats. In terms of developing and implementing such habitats, it is best to project the landscape contextualisation before implementing it,, and not vice versa, as is only too often the case. The very principle of the sub-division , as it was invented historically on sites like that at Vésinet, in the Yvelines department, is to install residences in a pre-existing landscape. More recently, pre-landscaping operations have been inspired by this. The landscape requirement for building permits aims at promoting this approach of contextualisation. Now that it has been implemented there has been a steady improvement in multi-unit construction projects, which are sometimes substantial as they involve coordinated developments. The provisions of the French law on urbanism enacted in 2000 ("SRU") will undoubtedly strengthen this process.