Liu Shaochuang, a scientist from the Institute of Remote Sensing Application with the Chinese Academy of Sciences (CAS), has pinpointed the accurate geological position of the river's source at 94 degrees, 40 minutes, 52 seconds east longitude and 33 degrees, 45 minutes, 48 seconds north latitude.

The source is located in the Jifu Mountains in Zaduo County, Yushu Tibet Autonomous Prefecture of northwest China's Qinghai Province, which is some 5,200 meters (17,060 feet) above sea level.

Liu has also used the remote-sensing technology to calculate the exact length of the river -- 4,909 km (3,050 miles). The 2,198 km (1,366 miles) section, which passes through China, is called the Lancang River. Once it flows out of China and continues to flow 2,711 km (1.685 miles) through Laos, Myanmar, Thailand, Vietnam and Cambodia, the river is called the Mekong.

The exact location of the river source has long been an international geological mystery due to harsh geographical environments and a lack of modern technology.

From the 1860s up to the end of the last century, a dozen scientific expedition teams, financed and supported by some of the world's most famous geographic research organizations, such as the French Society of Geography and Britain's Royal Geographical Society, have attempted to resolve the question.

As a result of these expeditions, there were several hypotheses put forward with regard to the location of the river's source, and the river's length was estimated to be between 4,200 and 4,880 km (2,610 miles and 3,032 miles).

"There are two rivers in the area of the Mekong source, the Zha'aqu in the north, and the Zhanaqu in the south. All of the foreign explorers traced the Zhanaqu to explore the source," said Liu.

Liu has adequate data suggesting that the Zha'aqu is longer and has more runoff than that of the Zhanaqu.

CAS took on the project of applying remote-sensing technology to locate the Mekong River source in 1999. Liu went into the source region in 1999, 2000 and 2002, respectively, and reached the source of the river twice to collect data.

His research is expected to provide basic scientific data so that the country can make further surveys of natural resources and conduct environmental monitoring along the river.

The Mekong River valley covers 810,000 square km (312,741 square miles), where China's southwestern region borders southeastern and southern Asia. It is a continental bridge linking China with ASEAN member countries.

The river valley is relatively underdeveloped, but there is huge potential for economic and trade cooperation with China. For example, China now imports agriculture goods such as rice and natural rubber from Thailand, while exporting automobile, auto parts and components, electrical and textile products to the country.

The Chinese government set up a preparatory liaison office for Lancang-Mekong river development in 1994. In April 2000, a treaty providing for the free navigation of the Mekong River was signed by China, Laos, Myanmar and Thailand. In April of the following year, cross-border navigation on the Mekong between the four countries commenced.

( October 28, 2002)