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 in the northern part of the Dead Sea and barely in the southern part. The Dead Sea zone's aridity is due to the rainshadow effect of the Judaean Mountains. The highlands east of the Dead Sea receive more rainfall than the Dead Sea itself. To the west of the Dead Sea, the Judaean mountains rise less steeply and are much lower than the mountains to the east. Along the southwestern side of the lake is a tall halite formation called "Mount Sodom". There are two contending hypotheses about the origin of the low elevation of the Dead Sea. The older