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
Northern Dvina River the west-flowing Vychegda River ( long). The combined river flows northwest into the White Sea, which it joins near the city of Archangelsk. Looking more closely, the Sukhona flows east and meets the north-flowing Yug River at Veliky Ustyug. The combined stream, now called the Northern Dvina, flows north about 60 km and receives the west-flowing Vychegda at Kotlas and then turns northwest to flow into the White Sea. The Sukhona-Vychegda was an important east–west transportation route while the Northern Dvina-Yug was a north–south route. The upper Sukhona is now connected by the Northern Dvina Canal to the Volga–Baltic Waterway,