Finite difference and finite element modelling of an aquifer in Cretaceous chalk

The studied aquifer is located in Cretaceous chalk near Liège (Belgium). It is recharged by infiltration through the overlying loess and conglomerate. Wells and pumping adits produce a daily flow of https://www.w3.org/1998/Math/MathML" display="inline"> 6 0000 m 3 . Mathematical models have been worked out to foresee the evolutions of the water table level and to get some additional informations about the drainance axis. The finite difference model NEWSAM has been used for the steady state study of the aquifer. Some values of transmissivity obtained by the calibration of this model have been further introduced into the finite element models. Two- and three- dimensional finite element models have been developped using an adapted LAGATHER thermic conductivity program in order to study unsteady conditions of the aquifer. These two models are useful and helpful to enable good location of the permeability variations due to geological features, and good estimations of hydrogeological balances. Conclusions are drawn from the comparison and the complementarity of the two models for this kind of study.