Estimating transmissivity fields and their influence on flow and transport: The case of Champagne mounts

Abstract

This paper presents a flexible and general methodology that combines hydrogeological and geostatistical modeling techniques to estimate a set of transmissivity fields and their influence on flow and transport. The methodology may be applied to any case with only hydraulic head observations, even if most of them are concentrated inside a small part of the entire domain of interest. It is applied here to the case of the Champagne chalk aquifer (France), where it is shown to be very efficient. The methodology is decomposed in three independent parts. First, a reference head distribution is constructed by kriging in order to constrain the inverse problem. As hydraulic heads and elevations are correlated, a smoothed digital elevation model is used as external drift. The inverse problem is then solved by using a simplified pilot point method with an efficient and easy‐to‐use minimization algorithm. Finally, geostatistical simulations combined with flow simulations lead to a set of acceptable transmissivity fields. The induced uncertainty is evaluated by calculating tracer concentrations, pointing out areas where flow behavior is uncertain and where new borings would be advantageously drilled.