Présentations Colloques

Oral Presentation
Session 6.01: Managed Aquifer Recharge
Baudron Paul
Investigating groundwater flow pattern at a bank filtration site in Québec province (Canada).
In Québec province, Canada, many tubewells are implemented in the vicinity of surface water masses. Pumped groundwater therefore potentially features a proportion of bank-filtrated water. Nonetheless, little is known about the reactivity of such systems to environmental and anthropogenic forcing and the subsequent consequences on contaminant attenuation capacity. This is mostly due to the transient regime of bank filtration sites. The purpose of this study is to characterize the spatio-temporal evolution of mixing rates and residence times of infiltrated surface water inside a bank filtration site located at a sandbar between two lakes with different hydrodynamic regimes. To this end, monthly campaigns for water heads, physico-chemical parameters (temperature, EC, pH, dissolved oxygen content, redox-potential), geochemistry and isotopic tracers (222Rn, 2H, 18O, 13C) are carried out at the 2 lakes and at 8 tubewells located at different locations along the sandbar. Results of the preliminary campaigns provide a better understanding of groundwater flow pattern in this complex system, particularly regarding mixing rates and residence time of groundwater. They also offer an insight on the transient regime of the system and on the possibility of preferential flow paths inside the sandbar.