Combining shallow hydrogeological characterization with borehole data for determining hydrofacies in the Valin River paleodelta

ABSTRACT: A hydrogeological characterization of hydrofacies in the Valin River paleodelta, in the Saguenay region (Quebec), has been conducted based on the identification of lithofacies and the estimation of their hydrogeological properties, such as the hydraulic conductivity. One of the objectives of this study was to develop a conceptual model of the granular aquifers constituting the paleodelta. The approach begins by characterizing the internal architecture of the aquifers using the lithofacies documented from the excavated faces of sand-pits in the study area. As part of this work, it was proceeded to exploit the deeper lithological data from the wells and piezometers localised in the study area to complete the conceptual model. Accordingly, two different approaches have been proposed and adopted to determine hydrofacies from wells and piezometers data. Both approaches are based on combining shallow hydrogeological information, collected on the exposed faces of the sand-pits investigated in the study area, with the geological information obtained from wells and piezometers. This paper describes the steps for determining hydrofacies, as well as the results obtained with each approach.