December, 2019
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info:eu-repo/semantics/altIdentifier/doi/10.4000/norois.9492
info:eu-repo/semantics/OpenAccess
Guillaume Paysant et al., « Secondary Hydrosystems Landscape Trajectories (West of France) – Ordinary Landscapes, Original Objects. Case Study of Aubance and Couasnon in the Loire Basin (1950-2016) », HALSHS : archive ouverte en Sciences de l’Homme et de la Société, ID : 10.4000/norois.9492
The small rivers in the west of France have the particularity of being of low energy and considered as “ordinary” spaces. The attention paid to them is often modest, despite the strong patrimonialization of which they are the object and the local issues that they concentrate. However, the landscapes of these hydrosystems have undergone significant changes related to several transformations of societies, particularly guided by public policies of recent decades. The modernization of agriculture in the second half of the twentieth century has resulted in rectification and recalibration of all rivers and conversion of grasslands from valley bottoms to crops. The current management of rivers, guided by the Water Framework Directive (2000) and its transposition into French law (Law on Water and Aquatic Environments, 2006), advocates the restoration of ecological continuity and “renaturation”. Taking the cases of the rivers Aubance and Couasnon, our research aims to retrace the landscape trajectories that these hydrosystems have followed and to identify the factors that have guided them. For this purpose, we have developed new data characterizing these objects to fill the gaps in information on the past status of these rivers. The results of this work have shown that from a datum at two dates of the trough route, a ground occupation elaborated by photo-interpretation and geomorphological indices, a systemic analysis made it possible to characterize the two hydrosystems and to capture their landscape trajectories. The geological basement, the more general context in which they are inscribed (Val d’Authion downstream of the Couasnon, alluvial plain of the Loire at the outlet of the Aubance) and geomorphology are all factors that have guided and oriented these transformations. The data and results can for example feed the reflections of the actors of the regional planning for their current actions of replanting hedges and restoration work of the beds of these two rivers.