Up to the 1970s, freshwater input in the DS was able to maintain a less salty topmost water layer (epilimnion) over-riding a salt-saturated bottom water layer (hypolimnion). The epilimnion was ~40 m deep, had a seasonal temperature variation of between 19 and 37°C and a salinity of about 30%. The water was particularly rich in sulphate and bicarbonate. Below the density interface (pycnocline, 40–100 m of depth) the hypolimnion was characterized by a uniform temperature of ~22°C and a salinity of >34%; it contained hydrogen sulphide and high concentrations of magnesium, potassium, chlorine, and bromine. The hypolimnion was unmixed for a long time. It is saturated with sodium chloride that precipitates as halite on the bottom (Abed 1985). The unique mineral composition of the DS water and its high salt concentration make it suitable for the production of potassium and magnesium. In addition, the high salt concentration provides natural cures against various skin sicknesses and the high oxygen content and low UVB exposure make the DS a prime area for therapeutic tourism (Abdel-Fattah and Pingitore 2009; Charlier and Chaineux 2009).