The effect of Dead Sea level fluctuations on the discharge of thermal springs

Abstract

Shalev, E. and Yechieli, Y. The effect of Dead Sea level fluctuations on the dis charge of thermal springs. Isr. J. Earth Sci. 56: 19–27. Thermal springs along the Dead Sea shore have been known to exist long before the great recession of the Dead Sea of the last 40 years. This work studies a possible mechanism that drives the brine discharge along the Dead Sea shore and the effect of the lake level fluctuations on the discharge. The Goldschmidt model suggested for the discharge of the springs at the Sea of Galilee cannot explain the discharge of the springs at the Dead Sea shore. Results from numerical modeling indicate that at steady state conditions the Dead Sea brine sinks through faults, migrates across tilted blocks, and then ascends back to the Dead Sea shore with fresh groundwater. The most signifi cant change in brine discharge is caused by water level changes in the lake. A recession of the Dead Sea causes a significant increase in brine spring discharge. As the Dead Sea level drops it interrupts the steady-state conditions. Since the groundwater was in equilibrium with a higher lake level, it now flows upwards to the lower lake level, reducing the overall hydraulic head. A rise of the Dead Sea level causes a decrease or even disappearance of the thermal spring discharge. An increase in the freshwater recharge in the mountain area causes negligible changes in this brine circulation.