Three-dimensional geologic modeling and visualization of the Virttaankangas aquifer, southwestern Finland

A need exists for a reliable and long-term water supply for the 285,000 inhabitants of the Turku area in southwestern Finland. In response to this need, there are plans to replace the present water supply from the surface sources with artificially infiltrated groundwater from a Quaternary esker aquifer called the Virttaankangas aquifer. New sedimentological studies of the Virttaankangas area have revealed the complexities of the esker system and its surrounding glacial, glaciofluvial, and glaciolacustrine geology. This led to the characterization of the hydrogeological units of the aquifer, the result of which has been a three-dimensional (3-D) truly integrated solids model that represents the geometry, interrelationships, and hydrostratigraphy of the study area. The 3-D model was made with EarthVision geologic modeling software. The 3-D geological model of the Virttaankangas aquifer can be used for planning the infiltration of river water into the aquifer and to understand the geologic and geographic boundaries of the hydrogeologic units hosting the groundwater reserve and the geologic relationships between the units. Another major outcome of this study is a powerful visualization tool that will be provided to municipal and government authorities who must understand the geologic complexities involved with water-resource planning prior to their decision making.Original Abstract: La region de Turku, dans le sud-ouest de la Finlande, a besoin d'alimenter en eau ses 285.000 habitants sur le long terme et de facon durable. Pour faire face a ce besoin, des plans sont proposes pour remplacer l'actuelle alimentation en eau a partir des eaux de surface par de l'eau souterraine provenant de l'infiltration artificielle dans un aquifere quaternaire d'un cordon sableux fluvio-glaciaire (esker), l'aquifere de Virttaankangas. De nouvelles etudes sedimentologiques de la region de Virttaankangas ont fait apparaitre la complexite du systeme de l'esker et de son environnement geologique glaciaire, fluvio-glaciaire et glacio-lacustre. Ceci a conduit a la caracterisation des unites hydrogeologiques de l'aquifere, dont le resultat a ete un modele des materiaux en trois dimensions reellement integre, qui represente la geometrie, les interrelations et l'hydro-stratigraphie de la region etudiee. Le modele 3-D a ete realise au moyen du logiciel de modelisation geologique EarthVision. Le modele geologique 3-D de l'aquifere de Virttaankangas peut etre utilise pour gerer l'infiltrati