关键词: 国际河流, 径流量, 水文特征

Abstract: Yalungzangbo River is the upper reach of Brahmaputra River. It s an important international river inChina as well as in Asia. Besides, it’s the highest elevation river in the world, with an basin area of about240 000 km in China and a river length of 2 239 km. Precipitation, snowmelt and groundwater are all sup-ply to the river. Runoff’ s division is charaterized by diversified runoff terrain and vertical stepschanges. Runoff depth changes from 5 000 mm to below 200 mm toward Northwest. Runoff changes are smallin years but large in a year. Trie runoff from June to September takes more than 65% of the total in ayear. The flood of main river has the feature of two-peak figure. The runoff calculated at the border is 150 bil-lion m³, ranks the third following the Yangze River and Pearl River. The sediment of the mainstream is below1.0 kg/m³. But owing to sevre cold and wind in the highest terrain, the bank sand become the sand source ofvalley of windy and sandy landform. It has a low mineral rate with an amount between 40 mg/1 ～ 250 mg/1and total hardness, so that water source of clean and better quality is availabe for industrial, agricultural, andlife water supply. Besides, it’s one of the region which has the lowest water temperature in China.The iceagebegins in winter, and band ice, flowing ice-flower rise much in main river and most of tributaries inYalumgzangbo River, and it’ s daily circle varies clearly.The abundant water energy and natural depositsranks second in China, especially at the big turn in lower reaches it has a big drop.Moreover, a dam withthe most installed capacity in the world could be built there.

Key words: international river, runoff, hydrology feature