South Hulsan Lake lies in the southern Hulsan
subbasin at the eastern edge of the
Qarhan Playa in the southeastern corner of the
Qaidam Basin at an elevation of . but it varies widely during and between years. It usually increases from the winter and spring floods and decreases during the summer and autumn. In 2014, it was as small as and as wide as . In the especially dry year of 2000, it was only . An inflow from the north by
mineral springs in the playa's northern
karst zone contribute a smaller volume of water but its much higher solute concentration greatly affects the lake and its sediments. In the area's hyperarid climate, there is generally only of annual rainfall but about of annual evaporation. It is never more than about deep. ==History==