As the longest river that flows from the north to the south in China, lancing River originates from Zhaqu of Tanggula Mountains in Qinghai province of China. It is called Lancang River after it flows through Changdu. Flowing toward the south, it is named as Mekong River after flowing out of China through Nanla estuary in Yunnan. When attending to group Chinese class in China, you may be told that it injects into the Pacific Ocean in Ho Chi Min city of Vietnam.
The whole length of this river is 2,354 kilometers with a drainage area of 16.5 square kilometers, enjoying the fame of the largest river in the south Asia area. The border of the upstream is Leiwuqi estuary with a length of 556 kilometers. The valley is shallow and the annual runoff is about 300 millimeter. In the middle reaches of 821 kilometers, the annual runoff is between 400 and 700 millimeter. The drainage after Gongguo Bridge is the downstream with narrow valley and an annual runoff of 200 to 400 millimeter.
The water supplement of lancing River is mainly the dominated by atmosphere precipitation supplement and supported by the ground water and alpine snow and ice melting. Teachers in semester Chinese program in China will tell you that the alpine snow and ice melting takes a certain proportion and the ground water takes a percentage of 50% of annual runoff. Starting from the middle stream, the percentage of the rain water supplement is increasing and the ground water and alpine snow and ice melting are decreasing. In the downstream, the rain water supplement is as much as more than 60%.
Annual runoff of the upper and middle reaches in winter just takes a proportion of 10%, over 10% in spring, about 50% in the summer and about 30% in autumn. The maximum flow generally occurs in July or August every year while the minimum flow occurs in January or February. The maximum runoff may occur from July to October in the downstream.
The gap of the riverbed of Lancang River is as high as 4600 meters. Learners who study Chinese in China should know it has great potential to develop because of the hydro energy of 27 million kilowatt. China has built three large hydropower stations like Manwan, Dachaoshan and Xiaowan, with a capacity of 7.05 million kilowatt. It is planned to build more stations along Lancang River.