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Geoelectrical and hydrochemical investigations for characterizing the salt water intrusion in the Khanasser valley, northern Syria

Asfahani J., Abou Zakhem B.

Acta Geophysica

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2013

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Vol. 61, no. 2

422--444

EN

An integrated approach of geoel ectrical and hydrochemical investi- gation surveys was proposed for indicating contact regions between saline and fresh groundwater in the Khanasser valley region, northern Syria. The qualitative and quantitative interpretations of 34 vertical electrical soundings (VES) enable to characterize the salt water intrusion laterally and vertically. The established iso-apparent resistivity maps for different AB/2 spacings obviously indicate the presence of a low-resistivity (less than 4 Ohmźm) zone related to the salt water intrusion in the Quaternary and Paleogene deposits. The different hydrochemical and geophysical parameters, such as electrical resistivity, total dissolved solids (TDS) and major ions concentrations used to characterize the salt water intrusion gave almost similar results in locating and mapping the different boundaries of the groundwater salinity. The proposed approach is useful for mapping the interface be tween different groundwater quali- ties, and can be therefore used to successfully characterize the salt water intrusion phenomenon in other semi-arid regions. The application of such an approach is a powerful tool and can be used for water resource management in the water scarce areas.

2

Quaternary aquifer transmissivity derived from vertical electrical sounding measurements in the semi-arid Khanasser Valley Region, Syria

Asfahani J.

Acta Geophysica

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2012

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Vol. 60, no. 4

1143-1158

EN

Vertical electrical sounding technique (VES) is used as an alternative approach to pumping test for computing the Quaternary aquifer transmissivity in the Khanasser Valley, Northern Syria. The method is inexpensive, easy and gives faster results with higher special resolution than the traditional pumping technique. The hydraulic conductivity values obtained using VES agree with the pumping test results, which in the Khanasser Valley vary between the order of 0.864 and 8.64 m/day (10–5 and 10–4 m/s). The probable location of the Quaternary aquifer in the Khanasser Valley is obtained through the transmissivity map derived from VES. The knowledge of transmissivity is fundamental for modeling and management processes in the Khanasser Valley. Other similar semiarid regions can benefit from the approach successfully applied in the study area.

3

Electrical resistivity investigations for guiding and controlling fresh water well drilling in semi-arid region in Khanasser Valley, Northern Syria

Asfahani J.

Acta Geophysica

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2011

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Vol. 59, no. 1

139-154

EN

Electrical resistivity survey is conducted in the Khanasser Valley, considered as a semi-arid region in Northern Syria, to guide and control fresh water well drilling. Vertical Electrical Soundings (VES) are carried out near the existing wells, which were also used to measure salinity and conductivity of water samplings. Resistivity and hydrogeological data combination made it possible to establish empirical relationships between earth resistivity, water resistivity, and the amount of total dissolved solids (TDS). These relationships are used in the present research in order to follow the TDS salinity variations, both in lateral and depth directions, along the longitudinal profile LP3, located in Khanasser Valley. Apparent salinity map under this profile is established for Quaternary and Paleogene deposits, and boundaries of suitable areas for fresh water well drilling in the totality of the Khanasser Valley are drawn. It was shown that excessive fresh-water depletion may affect the groundwater quality by upward seepage of saline water. Therefore, it is important to keep the fresh-salt water interface in a stationary situation. The geoelectrical methods widely contribute in determining the position of such interface, and can be easily applied in similar arid areas.