HYDROGEOLOGICAL MODELING OF THE SALINE HOT-SPRINGS AT THE SEA OF GALILEE, ISRAEL

Meteoric fresh groundwater from shallow aquifers and hot brines from d eep aquifers mix while emerging from several springs along the western coast of the Sea of Galilee, a freshwater lake located within the Dea d Sea Rift Valley, Israel. After the rainy season, when elevations of the groundwater table rise in the regional aquifers and discharge rate s of springs increase, solute concentrations decrease at Tabha springs but, surprisingly, increase at Fulya springs, apparently suggesting t wo different salinization mechanisms. Two detailed geologic cross sect ions were constructed, one across the rift valley at Tabha and a secon d at Fulya, each about 6 km deep and 70 km long. The hydrodynamics in these cross sections were analyzed using a two-dimensional finite elem ent code that solves the coupled variable-density groundwater flow and heat transfer equations. Numerical simulations indicate that a topogr aphy-driven flow model explains both spring systems, and the opposite salinity behavior results from the different hydrogeological configura tions of the two subsurface drainage basins. At Fulya, both aquifers, the shallow one and the deeper one, are partially phreatic, whereas at Tabha, the deeper aquifer is totally confined. The response of spring s to changes in elevation of groundwater table were simulated, reprodu cing field observations. This analysis has implications for the manage ment scheme for the lake and its surrounding aquifers.