Common valleys: spatial organisation, landscape and management models. Geohistorical analysis (Clain river, since the end of the 18th century)
Résumé
This paper deals with the landscape evolution of common small fluvial valleys in the west of France. During the 19th century, medieval watermills and weirs were modernised under the control of a State regulation implemented by civil engineers. Some of these hydraulic works, transformed during the industrial period, formed a landscape pattern. The Water Resources Archives highlight the characteristics of this pattern and how it was idealized as a model of productive river system, “perfect” and positive, from an ecological, economic and social perspective. First, we aim to describe this model (forms, organisation and management) and to explain its idealised representation. Then, we will retrace the evolution of these landscapes since the end of the 18th century by analysing data from multiple sources (archives, iconography and historical maps and specialised journals) and by conducting text analysis and diachronic mapping. The study investigates the Clain valley, a representative terrain of common small valleys in the West of France. Poitiers urban riverscape and its rural margins are specifically examined. We discuss the current management issues concerning these valleys and question those which, while pointing out the ecological consequences of the historical model, in fact call for alternative solution to the “well-managed” river model.