Coastal aquifer assessment using geophysical methods (TEM, VES), case study: Northern Crete, Greece

Abstract

The Geropotamos aquifer on the north-central coast of Crete, Greece, is invaded in some places by salt water from the Aegean Sea, with impact on freshwater supplies for domestic and business uses, including agriculture. Investigation of the aquifer using electromagnetic (TEM) and electrical resistivity (VES) measurement techniques has resulted in 1 D models and 2D imaging of geoelectric structure, depicting the zones of salination of groundwater in the aquifer. Comparisons with geological map and field-based observations, indicates that saline intrusion is likely to occur along fractures in a fault zone through otherwise low-permeability phyllite-quartzite bedrock, and emphasizes the critical role of fracture pathways in salination problems of coastal aquifers.