May, 2001 Letter from Zhou Changjin Regarding Differences in 1995 and 1999 Mekong Source Locations

(Ma Da was the Chinese Academy of Science representative for Earth Science Expeditions. The letter was written by Dr. Zhou to Ma Da at the request of Pete Winn, Science Director of ESE)

Dear Mr. Ma Da:

My name is Zhou Changjin. We went to Ganasongduo (94 36 40 E and 33 12 33 N) in 1994 with four Japanese (Masayuki Kitamura, Kazunori Fujimori, etc.), and measured the discharge of Zhayaqu and Zhanaqu to see which was largest. The Zhayaqu River has a discharge of 117.4 m3/s and the Zhanaqu River has a discharge of 32.3 m3/s which was measured on Sept. 4, 1994.

Jin Chang-xing and Zhou Chang-jin could not go to the source of Zhayaqu because we have a job in Beijing. Mr.Kitamura claims that Chen Yang accompanied his team to the base of the glacier on the north side of Guozongmucha mountain in 1994. In 1995 we reported the source of the Lancang Jiang as 94 41 35 E and 33 44 13 N, about 3 kilometers north of the location we reported in 1999. The 1994 reported location is the one that we discussed to with the Japanese team in 1994 in Beijing.

By field survey in 1999 we found the 1994 location is a tributary confluence of the Lasagongma river and the Lasabama river. It is not the correct location. For your review, following is an abstract of the article which is published in the Geographical Research, 2001. (2 ) 184-190, The Source of Lancangjiang (Mekong) River, Zhou Changjin and Guan Zhihua (Institute of Geography Science and Resources, Chinese Academy of Science ,Beijing 100101, China).

Abstract: Comprehensive survey and analysis of the headwaters of the Mekong River by use of GPS, GIS and SRS show that the source of the Mekong River is the Zhayaqu River which starts from the terminal of a small glacier on the Guozongmucha Mountain in Zaduo County, Qinghai Province. The altitude of the source is 5244 m, lying between 94 41 44 E and 33 42 31 N. The Mekong River flows through six Asian countries and ranks as the 12th largest river in the world. From the source to its first convergence of bigger tributaries of the Zhayaqu River and the Zhanaqu River, Ganasongduo (94 36 40 E and 33 12 33 N ), the Zhayaqu River has a length of 101.1 km, a drainage area of 2634.0 km2 and a discharge of 117.4 m3 /s which was measured on July 12, 1999. From Zhanahuohuozhudi (Rupsa La, 93 52.926 E and 33 16.534 N) to Ganasongduo, the Zhanaqu River has a length of 93.0 km, a drainange area of 1999.3 km2 and a discharge of 32.3 m3/s which was measured on July 12, 1999. At the confluence (Ganasongduo), the current direction of the Zhanaqu River is from west to east and the Zhayaqu River is from north to south. After joining, the river is called Zaqu River and its current direction is nearly from north to south. The run of the Zhayaqu River is similar to that of the Zaqu. From Ganasongduo to Qamdo in Tibet Autonomous Region, the Zaqu River is 518 km in length. Down from Qamdo to the outlet of the river inside China, the river is called Lancang Jiang, which has a drainage area of 167487 km2, a length of 2161 km and a mean annual discharge of 2180 m3/s.

Any other particulars required I shall be pleased to give you.

Yours sincerely, Zhou Changjin

History of First Descents of the rivers of Tibet and western China

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