Water-short Israel has only one under-utilized source of natural groundwater. Undertaken for a masters of science thesis, a recent hydrological mapping study of the Judea Group Aquifer reveals the extent of this untapped yet potentially vital resource. A report on the study was recently published in the Journal of Hydrology. Leehee Laronne Ben-Itzhak, working under the supervision of Prof. Haim Gvirtzman in the Hebrew University's Institute of Earth Sciences, provides detailed information in his study regarding the nature, volume and path of this reservoir of fresh water beneath the Judean desert. The aquifer begins in the Judean mountains and flows in a northeasterly direction toward the Dead Sea with out-flows at four springs adjacent to the Dead Sea: the Tsukim, Kane, Samar and Ein Gedi springs. There is also some sub-surface flow in the Dead Sea. According to Gvirtzman and Ben-Itzhak, the rain-fed aquifer contains an average yearly volume of some 100 million cubic meters of water, of which only about 20 percent is currently used, with the rest flowing into the Dead Sea. The water potential of the Judea Group Aquifer is sufficient to supply five perfect of the total current freshwater usage in Israel. The aquifer could mee the potable water needs of the towns of Ma'aleh Adumim, Bethlehem and Hebron at much lower cost than at present. Currently, Ma'aleh Adumim's water is brought hundreds of kilometers from the Kinneret via the National Water Carrier. This seems an unfortuntae waste, when there is water literally beneath the town, says Gvirtzman. In addition to the mapping survey carried out by Ben-Itzhak, who is now working on her doctoral thesis at the Weizmann Institute of Science, another study is currently being done by a second graduate student, Eldad Levi, also working under Gvirtzman. Levi is analyzing the interface between the fresh and saline groundwaters at various points in the Judea Group Aquifer, using a novel remote sensing technique called deep time-domain electromagnetic method. "These two studies have practical implications regarding future possibilities of groundwater development for the benefit of both Israelis and Palestinians residing in the area and for conservation of nature reserves located along the Dead Sea," says Gvirtzman. "The government has allocated these waters to the Palestinians, who are unfortunately doing nothing to fully exploit this available water source," he adds. As for the environmental impact of drawing more water that would otherwise flow into the Dead Sea, which is rapidly becoming depleted, Gvirtzman says that in any case the current groundwater flow into the Dead Sea is totally inadequate to halt that problem and that dramatic steps would have to be taken to resolve the situation. The study of the Judea Group Aquifer was conducted with the support of grants from the Ring Research Fund at the Hebrew University and from the Environment Ministry.