Combined geoelectrical and geoelectromagnetic survey for contributing to local hydrogeological regime-The case study of Delfini basin (Chios isl.-Greece)

Citation:

Papadopoulos, T. D., Alexopoulos, J. D., & Dilalos, S. (2020). Combined geoelectrical and geoelectromagnetic survey for contributing to local hydrogeological regime-The case study of Delfini basin (Chios isl.-Greece). Geology and Geophysics of Russian South (Geologiya I Geofizika Yuga Rossii), 10(1), 68–80. Федеральное государственное бюджетное учреждение науки Геофизический ….
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Abstract:

Relevance. In this paper the feeding mechanism of springs distributed around the broader area of Delfini at NE side of Chios Island is explored, in an effort to locate possible fresh water paths inland before they are discharged to the sea. The drilling of hydro wells for more production is of vital importance to cover the drinking and irrigation needs of the broader area. Aim. Although Chios has been extensively drilled in the past years the demand for further investigations comes from an increased water consumption during summer time in one hand and the inefficiency of alternative water resources (e.g. construction of dams, desalination units, etc) on the other hand. Methods. Geophysical methods were used (VLF and resistivity) to explore in detail water potential areas, like the broader area of Delfini, where during winter time huge quantities of fresh water discharge through springs to sea level. Results and its discussion. The presence of a confined aquifer composed mainly of limestones, which are overlain by clastic impermeable deposits, together with the existence of water potential bearing fracture zones determine the hydrogeological regime of the nearby area. It is also explained the presence of brackish waters at positive elevations found during summer time at nearby springs. It seems that the lateral extent of impermeable clastic deposits plays a crucial role in allowing the inland flow of seawater during summer time and combined with the presence of the confined aquifer of fresh water produce an upward mixing flow of fresh and seawater at springs of positive elevations. During winter time the huge amount of fresh water discharges do not allow the inland flow of seawater