ABSTRACT
Wei River Basin, which originates from the north side of Niaoshu Mountain, is the largest tributary of Yellow River. With its length 818 km and the basin area 13.5 × 104 km2, Wei River flows from east to west through the Loess Plateau in East Gansu, the Tianshui Basin, the Baoji Vally, the Guanzhong Basin, and make the confluence with Yellow River at Tongguan County in Shaanxi Province. As the largest branch of Yellow River, the average annual runoff of Wei River is 8.09 billion m3 at Huaxian Station. Located in the continental monsoon climate zone, Wei River Basin is characterized by abundant precipitation and high temperatures in summer and by rare precipitation and very low temperatures in winter. The annual precipitation of the basin is about 559 mm (Zhang et al., 2008).
