Effects of aquifer heterogeneity on the intrusion of seawater

In this study we examined the effects of geologic heterogeneity upon the seawater intrusion in coastal aquifers. Subsurface formations display spatial variability of the permeability such that it changes in an irregular manner in space over scales much larger than the pore scale. We describe hydraulic conductivity as random and characterize it statistically. The study domain is hypothetical aquifer with the properties similar to the actual case study of the Nitzanim aquifer in Israel. 100 realizations of the heterogeneous aquifer are generated and seawater intrusion problem using numerical code SUTRA [Voss, 1984] is solved. The results are statistically analyzed and compared to the common deterministic solution with homogeneous domain and macrodispersion coefficient. We examined the shape of the transition zone, intrusion length and salt concentration uncertainty as a result of aquifer heterogeneity. The results indicate that aquifer heterogeneity does affect the shape of the transition zone and shifts the zone inland compared to the deterministic solution with macrodispersion. The concentration uncertainty is more pronounced in the front of the transition zone and increases with depth