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
River Hertford River Hertford The River Hertford is a river in Yorkshire in the north of England. It is part of the River Derwent catchment area. The River Hertford starts close to Muston near the seaside town of Filey. Despite being only from the North Sea (to its eastern side) the river flows westwards for into the River Derwent at Haybridge. It is sometimes referred to as a 'Backward River' because it flows away from the sea. Ekwall suggests the name derives from a ford over the river, which became the name by back formation. Star Carr, a Mesolithic archaeological site, lies