Estimating mean residence times and flow velocities to quantify recharge to the Western Dead Sea aquifer system using multiple environmental tracers

The geologically complex, partly karstic limestone aquifers located west of the Dead Sea provide vital freshwater sources for all populated areas from Ramallah to Hebron. Discharge from these aquifers also sustains sensitive ecosystems located along the western shore of the lake. Recharge to these aquifers is restricted to winter precipitation events, which only occur in Hebron and Jerusalem uplands. To inform future sustainable water management strategies, a detailed characterization of these aquifers, including the volume of sustainable extraction is needed. In this study, the time scales of groundwater recharge to the two main aquifers were estimated through the sampling and interpretation of a suite of young age environmental tracers including tritium (³H), chlorine-36 (³⁶Cl), chlorofluorocarbons (CFC-11, CFC-12 and CFC-113) and sulfur hexafluoride (SF₆).