Transient groundwater-lake interactions in a continental rift: Sea of Galilee, Israel

The Sea of Galilee, located in the northern part of the Dead Sea rift, is c urrently an intermediate fresh-water lake, It is postulated that during a s hort highstand phase of former Lake Lisan in the late Pleistocene, saline w ater percolated into the subsurface. Since its recession from the Kinarot b asin and the instantaneous formation of the fresh-water lake (the Sea of Ga lilee), the previously intruded brine has been flushed backward toward the take. numerical simulations solving the coupled equations of fluid how and of solute and heat transport are applied to examine the feasibility of this hypothesis. A sensitivity analysis shows that the major parameters control ling basin hydrodynamics are lake-water salinity, aquifer permeability, and aquifer anisotropy, Results show that a highstand period of 3000 yr in Lak e Lisan was sufficient for saline water to percolate deep into the subsurfa ce. Because of different aquifer permeabilities on both sides of the rift, brine percolated into aquifers on the western margin, whereas percolation w as negligible on the eastern side, In the simulation, after the occupation of the basin by the Sea of Galilee, the invading saline water was leached b ackward by a topography-driven flow, It is suggested that the percolating b rine an the western side reacted with limestone at depth to form epigenetic dolomite at elevated temperatures. Therefore, groundwater discharging alon g the western shores of the Sea of Galilee has a higher calcium to magnesiu m ratio than groundwater on the eastern side.