When the level of a saline lake drops, the lake becomes more saline, and may dry up entirely, causing the collapse of fisheries, the disappearance of animals whose habitat has been destroyed, higher salinity of land bordering the lake as dried salt blows onto it, unemployment and severe health problems. The climate may also become more extreme. Usually the drop in lake level is due to diverting for crop irrigation, domestic use and flood prevention too much of the water from freshwater streams that feed the lake.
A salt lake contains more than 3 grams of salt per litre of water. Since 1960, the levels of many of the world's major salt lakes have fallen drastically: the Aral Sea has fallen 15 metres, Quinghai Hu (China) 10 metres, the Dead Sea 8 metres, and Lake Corangamite (Australia) 3 metres. The 44,000 tonne fishery in the Aral Sea has collapsed, and groundwaters have been polluted by agricultural pesticides.