IDENTIFICATION DU POTENTIEL EN EAUX SOUTERRAINE DE LA MORAINE DE ST-NARCISSE EN MAURICIE-EST

ABSTRACT: The St-Narcisse morainic complex is a major formation that stretches along the southern margin of the Canadian Shield and extends from the city of St-Simeon in Quebec to the Great Lakes in Ontario. This vestige of a cooling period dated from the Younger Dryas (12.7-12.4 cal. Ka BP) was settle down during a re-advance of the Laurentidian Ice Sheet (LIS) and cuts across the study area (i.e. eastern Mauricie). Groundwater found in these areas is the main source of drinking water and is locally exploited for supplying several municipalities (i.e. St-Narcisse, St-Prosper, St-Maurice, among others), which attests of the local aquifer capacity of the moraine. Here, we present the sedimentary and stratigraphic properties of the St-Narcisse Moraine in eastern Mauricie. The aim of this study is to propose an approach to characterize a regional aquifer of a moraine with TEM method. The objectives were therefore to collect geophysical data in support of hydrogeological mapping to: 1) improve the understanding of the sediment architecture in the moraine; 2) to globally determine the location and delineating the spatial extent of its regional aquifers; 3) globally define the hydraulic connection of the Saint-Narcisse moraine aquifers in eastern Mauricie. To apply efficiently TEM method, we have defined a calibration chart of electrical resistivity values associated with each of the typical sediment class found inside the Saint-Narcisse Moraine in eastern Mauricie. This chart will allow us to: 1) acquire an equivalence of the electrical resistivity values for the dry and saturated sediments; 2) cover as much space as possible in the study area to use all the TEM results collected during the field campaign, with or without boreholes or piezometric observations.