Dead Sea 342 parts per thousand (in 2002), and a temperature that swung between and . Underneath a zone of transition, the lowest level of the Dead Sea had waters of a consistent temperature and complete saturation of sodium chloride (NaCl). Since the water near the bottom is saturated, the salt precipitates out of solution onto the sea floor. Beginning in the 1960s, water inflow to the Dead Sea from the Jordan River was reduced as a result of large-scale irrigation and generally low rainfall. By 1975, the upper water layer was saltier than the lower layer. Nevertheless, the upper layer remained
Dead Sea balsam tree, which could be made into perfume. By the 19th century, Jericho's fertility had disappeared. There are several small communities near the Dead Sea. These include Ein Gedi, Neve Zohar and the Israeli settlements in the Megilot Regional Council: Kalya, Mitzpe Shalem and Avnat. There is a nature preserve at Ein Gedi, and several Dead Sea hotels are located on the southwest end at Ein Bokek near Neve Zohar. Highway 90 runs north-south on the Israeli side for a total distance of from Metula on the Lebanese border in the north to its southern terminus at the Egyptian border