Salt water intrusion with heterogeneity and uncertainty
Résumé
This paper is concerned with variable density groundwater flow modeling and applications to sea water intrusion in coastal aquifers. We focus on the effects of hydrogeologic variability and uncertainty. One major source of uncertainty is the multidimensional heterogeneity of aquifer properties like permeability, while other uncertainties are related to space-time variability of hydrologic and human inputs (sink/source terms). The mathematical approach considered in this work is to introduce a stochastic (probabilistic) representation of variability in the equations governing salt/fresh water flow, based essentially on Darcy's law and mass conservation principles. Our model implements a numerical finite volume scheme to solve these equations for simplified “sharp interface” problems. In particular, we study the effects of heterogeneity on the structure of the salt wedge. In fine, the objective is to obtain measures of dispersion and uncertainty, and to assess the efficiency of hydraulic remediation methods in heterogeneous coastal aquifers. This work is a preliminary contribution to an international, multisite research project on endangered coastal aquifers, involving several mediterranean countries.