October 8, 2006
A satellite image of the Turpan Depression nestled at the foot of China's Bogda Mountains. It is courtesy of Jeff J Hemphill at UCSB Department of Geography, Santa Barbara, California:
Turpan Depression (salt lakes sand dunes below sea level), China, Landsat
Desert lakes are generally shallow, temporary, and salty. Because these lakes are shallow and have a low bottom gradient, wind stress may cause the lake waters to move over many square kilometers. When small lakes dry up, they leave a salt crust or hardpan. The flat area of clay, silt, or sand encrusted with salt that forms is known as a playa.
Turpan was once an important strategic point on the Silk Road. Is this desert and salt lake the result of human exploitation from agriculture based on tapping the water in the wells at the base of the mountains? The Karez, an irrigation system of wells connected by underground canals, is considered as one of the three great ancient projects in China.
|