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 Essenes settled on the Dead Sea's western shore; Pliny the Elder identifies their location with the words, "on the west side of the Dead Sea, away from the coast ... [above] the town of Engeda" ("Natural History", Bk 5.73); and it is therefore a hugely popular but contested hypothesis today, that same Essenes are identical with the settlers at Qumran and that "the Dead Sea Scrolls" discovered during the 20th century in the nearby caves had been their own library. Josephus identified the Dead Sea in geographic proximity to the ancient Biblical city of Sodom. However, he referred to the