Fonctionnement hydro-sédimentaire et bilan sédimentaire du lac de Saint-Germain-de-Confolens (Charente, France) : paramètres géomorphologiques à prendre en considération dans la gestion du lac

Abstract

Lake Saint Germain was created near Saint-Germain-de-Confolens (Charente, France) for drinking water production in 1972. Since then, various short-term studies have shown water quality to degrade, and sedimentation to gradually fill the lake. The lake appears to have lost 42 % of its initial water capacity due to present mean sedimentation rates nearing 8000 m3.year-1. A sedimentary balance shows that this phenomenon can be attributed to watershed allochtonous particulate inflow for 87 %. Sediment fluxes and their lacustrine accumulation act in turn as in-lake nutrient sources accelerating the eutrophication process. As a conclusion for this study, some solutions are proposed to improve drinking water production sustainability.

Keywords

• water quality
• management
• artificial lake
• lacustrine sedimentation
• sedimentary balance