Saltwater intrusion in an irrigated agricultural area: combining density-dependent modeling and geophysical methods

Saltwater intrusion is one of the most important water quality problems in coastal aquifers, especially in areas with increased water demands. Geophysical techniques can provide a non-invasive and cost-effective approach for determining the geometrical characteristics of an aquifer and for guiding the saltwater intrusion modeling process and in turn reducing the model’s inherent uncertainty. In this work, the above concept was applied in the Tympaki basin in Heraklion, Greece. The transient electromagnetic method was used to obtain an accurate 3-D geomodel (bedrock geometry and fault detection) of the basin. This, in turn, was used to guide the construction of a density-dependent groundwater flow and transport simulation model. The results show significant advancement of the saltwater intrusion front in the northern part of the study area, while the phenomenon is less pronounced in the central and southern parts. This is mainly attributed to the combined effect of the fault in the northern part of the basin, the uplifted Neogene deposits in the central part and the freshwater inflow from the Festos corridor in the southern part.