柴达木盆地是我国著名的内陆盆地之一。位于青海省西北部,东经90°07′—99°20′,北纬34°40′—39°20′,东起苦海,西至茫崖镇,南以昆仑山系分水岭为界,北到当金山口。

An annual precipitation and depth of runoff in Qaidam Basin decrease from southeast to northwest, i.e.. from 250 mm to 20 mm and from 50 mm to 0, respectively. The vertical distribution of precipitation is characterized increase with elevation rising. The vertical distribution of runoff may be divided into three zones, as follows: producing zone in the mountainous area, vanishing zone on the top of an alluviail fan and overflow zone at the forefront of an alluvial fan.The rivers souroed by runoff may be divided into four types, namely, rain fall water type, rain fall water-groundwater type, groundwater type, and ice and snow-melt water type. So the runoff distribution changes a lot annually, but its variation is small from year to year.The stream-frozen period is about 5-6 months in the northwest and 3-4 months in the east. While some stream are never frozen.Because of drying climate strong weathering and steep slop, most of streams carry a large amount of sediments. However, a small specific yield makes this region as a some with low erosive modulus in China.Degree of mineralization in streamflow decreases with a range from 200 m^r 1 to 1000 mg/l or more, and hydrochemical pattern changes from HC03--Ca++ to Cl-Na+ with elevation decreasing.