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6582002 
Journal Article 
A correction for Dupuit–Forchheimer interface flow models of seawater intrusion in unconfined coastal aquifers 
Koussis, AD; Mazi, K; Riou, F; Destouni, G 
2015 
Yes 
Journal of Hydrology
ISSN: 0022-1694 
525 
277-285 
WOS:000355885600022 
Summary Interface flow models that use the Dupuit–Forchheimer (DF) approximation for assessing the freshwater lens and the seawater intrusion in coastal aquifers lack representation of the gap through which fresh groundwater discharges to the sea. In these models, the interface outcrops unrealistically at the same point as the free surface, is too shallow and intersects the aquifer base too far inland, thus overestimating an intruding seawater front. To correct this shortcoming of DF-type interface solutions for unconfined aquifers, we here adapt the outflow gap estimate of an analytical 2-D interface solution for infinitely thick aquifers to fit the 50%-salinity contour of variable-density solutions for finite-depth aquifers. We further improve the accuracy of the interface toe location predicted with depth-integrated DF interface solutions by ∼20% (relative to the 50%-salinity contour of variable-density solutions) by combining the outflow-gap adjusted aquifer depth at the sea with a transverse-dispersion adjusted density ratio (Pool and Carrera, 2011), appropriately modified for unconfined flow. The effectiveness of the combined correction is exemplified for two regional Mediterranean aquifers, the Israel Coastal and Nile Delta aquifers. 
Coastal aquifer; Seawater intrusion; Submarine groundwater discharge; Sharp interface; Outflow gap; Transverse dispersion