The Allier River

The 420-km-long Allier River is the largest tributary of the Loire. It is exceptional in France as a large river that still has active river dynamics. Numerous human activities modify this dynamic (such as historical aggregate extraction from the river bed and floodplain, and hardening and reshaping of its banks). These different activities contribute in particular to limit lateral erosion and thus favor bed incision in the absence of sufficient sedimentary recharge. In addition, the Allier valley presents important heritage and biodiversity issues with Natura 2000 zones and protected sites. The alluvial groundwater of the Allier also constitutes a resource for the drinking water needs of 400,000 users living in the downstream Allier basin. 
 
Today, several actors are getting organized to restore and preserve of the river dynamics to reduce incision in the Allier River, allow the river to dissipate its energy, preserve its functionality and adjust to hazards. This action is included in the Local Water Development and Management Plan, the Schéma d’Aménagement et de Gestion des Eaux (SAGE), and is also the objective of the Conservatoire des Espaces Naturels (CEN) Auvergne through various actions carried out in the watershed. These actions include identification and monitoring of potentially erodible areas, land acquisition, and removal of riprap from banks. The CEN qualifies these actions as nature-based solutions insofar as they aim to mitigate the effects of extreme climatic phenomena, to promote the river's capacity to adapt to natural risks (floods and droughts) and to guarantee the preservation of natural areas and promote their biodiversity.