The anthropogenic nature of present-day low energy rivers in western France and implications for current restoration projects
Laurent Lespez|Vincent Viel|A.J. Rollet|Daniel Delahaye
As in other European countries, western France has seen an increase river restoration projects. In this paper, we examine the goals, methods and objectives with respect to long-term trajectory understanding of contemporary dynamics small low energy rivers typical lowlands Western Europe. The exhaustive geomorphological, paleoenvironmental historical research conducted Seulles basin (Normandy) provides very accurate documentation nature place different legacies fluvial systems have inherited. sedimentation rate valley bottom multiplied by a factor 20 since end Bronze Age generated dramatic changes forms. Hydraulic control bottoms drainage throughout last millennium channelized within these deposits. single meandering channel which characterizes today is legacy delayed complex effects long term exploitation system. Bring light that “naturalness” restored might be questioned. Our emphasizes gap between poor knowledge functioning concrete works undertaken, including dam weir removal. Account history required, not only produce pedagogic “river degradation” but more fundamentally (i) situate current system try identify thresholds anticipate potential turning points context climate land use change, (ii) understand role morphosedimentary on dynamics, (iii) open discussion reference or expected states (iv) sustainability ecological restoration. To conclude, point out necessity take into account hybrid rural environments develop specific evaluation protocols would include both biophysical processes usual human activities could way share overcome conflicts socioeconomic needs environmental issues.
Geomorphology|HAL (Le Centre pour la Communication Scientifique Directe)