When « risk » becomes a development lever…
Frédéric Bonnet, 2014
This article starts from a feedback from 5 case studies (geographically heterogeneous) to show how risks, from constraints, can become levers for a virtuous territorial development and the construction of resilient cities and habitats. The author also shows how the acceptance of risk allows the renewal of categories of thought towards new forms of preventive urbanization and a landscape reflection on the means of protection put in place to minimize exposure to hazards.
For the past year, I have been coordinating a multidisciplinary team within the framework of the National Workshop on « territories undergoing change and subject to risks » launched by the Ministry of Territorial Equality and the Ministry of Ecology. This project workshop provides elected officials with « interactive » engineering, during direct meetings, according to the participative principle imagined by Christina Garcez. Experts, elected officials and state services meet several days around a table and drawings to develop urban alternatives together, the project and the rule being intertwined here. In addition to being a great experience in urban planning, where politics and technology come together, this work on the vulnerability of territories shows that we can « invert the gaze » and transform the constraint into a lever, an aid to better think about urban development.
We study five very different sites:
two industrial valleys in Lorraine (the Orne and the Fensch),
the Tours valley between the Loire and the Cher,
the Oise valley between Creil and Compiègne,
the Argens valley in the Var,
and the municipalities of Chelles and Neuilly-sur-Marne on the banks of the Marne.
In all cases, the various risk prevention plans, whether industrial, related to flooding or mining collapses, are perceived as brakes on development, and effectively affect the constructability of cities.
The project work makes it possible to resolve certain contradictions. Based on an effective consideration of hazards, it allows for invention and, in so doing, perhaps more virtuous forms of urbanization. The paradoxes are multiple.
On the one hand, the cities thus constrained by their PPRI decentralize and favor a plateau urbanization, as in the case of Lorraine, Oise or Tours. New districts and business parks are thus established far from all services and public transport, on excellent agricultural land, at great infrastructure expense, in clear contradiction with other public policies (reduction of land consumption, greenhouse gases, promotion of mixed functions, etc.). Conversely, well-equipped and hyper-serviced city centers (a TGV station in Saint-Pierre-des-Corps, for example) are frozen. It is clear that giving up on these historic urban areas or overly disrupting their development is not only an urban aberration, but also an ecological and economic one.
Most of these sites have been subject to hazards for centuries : the richest and best-served areas of our metropolises often straddle a river, are on the seashore, and are therefore vulnerable. But memory fails, and each event seems to erase the memory of past disasters, with which we had often learned to live. This cultural dimension is essential : in most cases, it is not human occupation, but its form and connections that pose a problem. Thus the Argens valley is fertile precisely because of the floods, which caused less devastation when the crops were fruit trees and not above-ground greenhouses. Rediscovering modes of occupation that are compatible with the inevitable rise in water levels is a way of working, which questions the criteria by which we judge the economic profitability of activities. Fruit was abandoned because it was too competitive with Spanish production. Rather than supporting a sustainable production with high added value, we prefer to compensate heavily, not to mention the ecological and financial costs to support the productions of the south of Europe by irrigating them excessively. This costs more overall and does not reassure us about the common agricultural policy and « free and undistorted competition ». Everything fits together. This being the case, if we take note of these macro-economic dysfunctions, we also note that the non-constructibility of the land is sometimes an opportunity. This distinguishes the Argens from the ordinary Côte d’Azur, now devastated by unbridled urbanization. This agricultural gap is an opportunity, a support for development, and we have shown that immense capacities exist, outside of the hazards, as long as we definitively give up speculating on the constructability of the valley, and integrate its agricultural character into the overall urban strategy. In the Oise, the protection of significant portions of the forty kilometers of valleys can improve ecological continuity, the hydraulic behavior of the river and the quality of landscapes, and free up, in other selected places, new development land. As a result, one of the only logistics platforms where river, road and rail meet in the Île de France will not be condemned to vegetate.
Choosing not to build here rather than there, over the long term and on a large scale, is in itself a considerable step forward: it rethinks the way urban planning is done in France, reintroduces the major territorial logics into the project, and insists on metropolitan complementarities. In Tours, the two municipalities of the twenty kilometers of the confluence peninsula have chosen to take note of the inconstructibility, and to develop leisure activities and proximity tourism, for the benefit of neighboring cities. In exchange, they ask for metropolitan solidarity. Here again is a step forward, where the governance and representation of the urban area is progressing, « thanks to the risk ».
Where we accept to live with risk, urban and architectural invention is the order of the day, and insists on transcalary solidarity: it is the neighborhood and the city that must resist, not only the architecture, which, moreover, cannot be satisfied with pre-established models, neither the individual house in series, nor the silly investor’s building. Phew ! finally a way to impose, by the force of nature, as Alberti would say, a creative and multiscalar reflection ! Saint-Pierre-des-Corps is a pioneer, with a project that has been carried out for twenty years on all scales: this is the place to go in France to visit a « resilient housing ". In Lorraine, the « fontis » (mine collapses) are also forcing us to invent new ways of building, stimulating research and production in the eco-construction sector.
Finally, a last methodological reversal, infrastructures (such as dykes or canals), sometimes necessary, become once again a landscape issue, an opportunity to improve the city, and no longer a technical object that cuts and separates. One suddenly realizes that the reinforcement of a dike, if it is included in an ambitious urban project, transforms the future of an entire city. In Tours, it is the thousand-year-old contact with the river and the landscape of the hillsides classified as Unesco Heritage that are at stake. A metropolitan project can be built on the updating of a work of art.
There is therefore good reason to hope: as long as the sense of the project is rediscovered, as long as politics once again takes over the technical field, as long as the experts talk to each other, between disciplines, and hybridize with each other’s knowledge, the taking into account of risks is the vector of new urban strategies.
To access the PDF version of the Tous Urbains magazine issue, n°8