Isotope hydrology of deep groundwater in Syria: renewable and non-renewable groundwater and paleoclimate impact

Al-Charideh, A.; Kattaa, B.

Isotope hydrology of deep groundwater in Syria: renewable and non-renewable groundwater and paleoclimate impact | Hydrologie isotopique des eaux souterraines profondes en Syrie: eaux souterraines renouvelables et non renouvelables et impact des paléoclimats Hidrología isotópica del agua subterránea profunda en Siria: agua subterránea renovable y no renovable e impacto paleoclimático هيدرولوجيا النظائر للمياه الجوفية العميقة في سوريا: المياه الجوفية المتجددة وغير المتجددة، وتأثير المناخ القديم 叙利亚深层地下水的同位素水文状况:可更新和不可更新的地下水及古气候影响 Hidrologia isotópica de águas subterrâneas profundas na Siria: águas subterrâneas renovável e não renovável e impacto paleoclimático

2016

Al-Charideh, A. | Kattaa, B.

The Regional Deep Cretaceous Aquifer (RDCA) is the principal groundwater resource in Syria. Isotope and hydrochemical data have been used to evaluate the geographic zones in terms of renewable and non-renewable groundwater and the inter-relation between current and past recharge. The chemical and isotopic character of groundwater together with radiometric ¹⁴C data reflect the existence of three different groundwater groups: (1) renewable groundwater, in RDCA outcropping areas, in western Syria along the Coastal and Anti-Lebanon mountains. The mean δ¹⁸O value (−7.2 ‰) is similar to modern precipitation with higher ¹⁴C values (up to 60–80 pmc), implying younger groundwater (recent recharge); (2) semi-renewable groundwater, which is located in the unconfined section of the RDCA and parallel to the first zone. The mean δ¹⁸O value (−7.0 ‰) is also similar to modern precipitation with a ¹⁴C range of 15–45 pmc; (3) non-renewable groundwater found in most of the Syrian interior, where the RDCA becomes confined. A considerable depletion in δ¹⁸O (−8.0 ‰) relative to the modern rainfall and low values of ¹⁴C (<15 pmc) suggest that the large masses of deep groundwater are non-renewable and related to an older recharge period. The wide scatter of all data points around the two meteoric lines in the δ¹⁸O-δ²H diagram indicates considerable variation in recharge conditions. There is limited renewable groundwater in the mountain area, and most of the stored deep groundwater in the RDCA is non-renewable, with corrected ¹⁴C ages varying between 10 and 35 Kyr BP.

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