Xihanshui (formerly known as Rhino River), a tributary of the right bank of Jialing River, has a drainage area of about10/000 square kilometers, a river length of more than 240 kilometers, an average gradient of about 3.6‰, and theoretical hydropower reserves of more than 270,000 kilowatts. It belongs to the high mountain, and the northwest is higher than the southeast. The main tributaries on the east side of the upstream basin originate from loess hills with an altitude of about1750 ~ 2000m. The north side is adjacent to the Weihe River system of the Yellow River, and the watershed is high in the west and low in the east. Wufeng, the birthplace of Qingshui River, a tributary on the west side, is 3550 meters above sea level, which is separated from Bailong River here. The peak elevation of the middle reaches is about 2,000-2,500m, and the mountain in the lower reaches gradually decreases, and the peak elevation between the middle reaches and the confluence of Yaoping River is1414m.
There are two sources of water in the Western Han Dynasty. The southern source originated from Zhaizi Mountain, Damen Town, Tianshui County, Gansu Province, with an altitude of 1920 meters, commonly known as Nanhe; Beiyuan, or Jacky, originated from Wanshou Mountain in Pingnan Township, Tianshui City, Gansu Province. It was called the Western Han River only after it merged with Nanyuan South River in front of Tianshui Town, and then merged into Jialing River in Lueyang County, Shaanxi Province. Qingshui River, a tributary of the right bank of the Western Han River, has a drainage area of 1.638 square kilometers, which is slightly long from west to east and flows into the Western Han River in Lixian County. The main stream is 83 kilometers long, with an average gradient of more than 1.7‰.
The water system in the Western Han Dynasty is dendritic, with its main tributaries extending to the east and west respectively, its main tributaries to the west and its trunk bent to the east. There are 9 first-class tributaries with a basin area of over 300 square kilometers, including 6 tributaries with a basin area of over 500 square kilometers.