3D geological modelling of fluvio-glacial aquifers to improve water work operations

Fluvio-glacial aquifers in subalpine quaternary basins are global sources of drinking water.
Water works need to consider the geological framework of such aquifers to optimize 
groundwater management. This can be achieved by developing 3D geological models, which 
act as powerful tools for aquifer visualization and estimation of hydraulic properties. In recent 
years 3D geological modeling has emerged as an asset to sustainable groundwater management. 
However, the implementation of such models is no trivial task and requires expert geological 
knowledge. In this study a 3D geological model is developed for a subalpine quaternary basin,
that provides drinking water to a major city. The relationship between aquifer geometry and 
heterogeneity, preferential flow paths, and observed hydraulic and hydrochemical trends is
investigated. A database consisting of around 300 bore logs as well as geophysical, hydraulic
and hydrochemical data provides the foundation for the 3D geological model. The software 
package Leapfrog Works is employed to create the model. The resulting model depicts the 
complexity of the fluvio-glacial stratigraphy and the hydrogeological units of the study area 
and demonstrates the retarding effect that glacial terraces can have on flood wave propagation 
in aquifers. It allows the assessment of total groundwater volume and areas of low hydraulic 
conductivity. Our understanding of aquifer interconnectivity and constraints imposed on 
groundwater flow in fluvio-glacial quaternary sediment basins is improved. As such, 
recommendations for future groundwater explorations in subalpine basins are provided.