ABSTRACT
The characterisation of aquitards is obligatory to quantify the amount of leakage contributing to the recharge of aquifers in a multilayered system. This characterisation involves determining their hydrogeological heterogeneity. In the area of Bordeaux (south west France), the heterogeneity of the aquitards was studied at two different scales. The use of well logs allowed clarification of the vertical system and the geology of the aquitards. A high resolution approach consisted of drilling a well directly in an aquitard and studying the evolution of pressures across it. In addition, physical measurements on cores provided the hydraulic properties. These two methods gave information about the geological nature of the aquitards and their permeabilities. The results were used to update the hydrogeological model in order to assist in enhancing freshwater exploitation.
