The new EU Water Framework Directive (Directive 2000/60/EC) implies that hard rock units will need to be considered as aquifers, and to be hydrogeologically and hydrogeochemically characterized. This is not a straightforward task, given that such aquifers are heterogeneous, discontinuous and strongly three-dimensional in the distributions of both hydraulic and hydrochemical properties. The Geological Survey of Norway has recently carried out characterizations of Norway’s hard rock aquifers using simple non-parametric statistical techniques, focusing on median and percentile values for aquifer properties and concentrations of chemical parameters. Such characterizations reveal far larger parameter ranges within given aquifer lithological units than between different units. Indeed, for most lithologies, median well yields and concentrations of major chemical parameters (e.g. pH, major ions) are remarkably similar. For certain elements, however, systematic differences can be detected. For example, elements such as uranium, radon and fluoride are significantly enriched in Precambrian granites and gneisses, and depleted in anorthosites.

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