Using stable isotopes to delineate the relations between sub-aquifer systems in the eastern slope of Bethlehem-Hebron to the Dead Sea/Palestine

Abstract

This study used stable isotopes 18O, 2H, and 3H in addition to hydro chemical and hydraulic data to explain the relations between different sub-aquifer systems in the Bethlehem-Hebron area. This area is suffering from high water shortage. The results indicate different recharge processes which occur within the upper and lower Aquifer systems of the mountain aquifer, and the structural features play an important role in this process. The isotopes emphasize the previous finding about the role of the structure, mainly, the extensive-folded anticlinorium that forces groundwater to flow through synclinal axes up- and downward, with different recharge mechanisms. While the lower aquifer received limited direct recharge from the exposed Bet Kahil formation in the upper part of the mountain, some of the upper aquifer groundwater seeping down through structural axes and faults fed the lower aquifer with additional amount of water. This process is attributed to the lowering of hydraulic head that varied seasonally. On the other hand, the direct recharge for the upper aquifer can be enough unless a huge amount of water from the upper aquifer seeping down due to steep hydraulic gradient to the Dead Sea springs. This process is apparently responsible for the quick drawdown of the groundwater level besides depletion of some wells drilled recently during the last decade in the upper aquifer. Delineating the relations between different aquifer systems within the study area can give further explanation and help the stakeholders to manage the water shortage problem, taking into account the main finding about aquifer relations in the future plans.