On the construction of 3D geological models for applications in regional hydrogeology in complex Quaternary terrains of easter

Predicting spatial variation of hydrogeologic parameters requires a prior knowledge of the subsurface lithology, stratigraphy and architecture of the geological units in a study area. This is particularly true in the complex glacial and glaciomarine terrains of eastern Canada. However, the work required to transform a qualitative knowledge-based geological model into a full 3D geological model and then into a numerical format for input to groundwater flow models is by no means trivial. These models are based to a large extent on inferences from scattered information integrated in datasets, which come from many different sources with their own errors and uncertainties. This problem is magnified by the lack of standards and by the large size of archival datasets, which have been assembled in vastly differing contexts and which, may have undergone several transfers from one format to another. In spite of these difficulties, integrating this information is a necessity, especially in regional-scale investigations where the high cost of acquiring new subsurface data is a major issue. Thus, there is a need to qualify information according to source so that it can be appropriately weighted in the typically subjective interpretation process.