More than 100 years after Swedish explorer Sven Hedin announced the discovery of the origin of the Indus river, a Chinese scientist has challenged the claim with the help of high-resolution, remote-sensing satellite images and a field investigation to come up with a new finding.

The new point of origin is said to be located in a valley, northeast of Kailash, the highest peak of the Gangdise Mountain, in the west region of Tibet, southwest of China, according to Liu Shaochuang, a researcher with the Institute of Remote Sensing Applications under the Chinese Academy of Sciences.

"The headstream, called Banggokong by local Tibetans, is about 30 kilometers away from the place that Sven Hedin believed was the source of the river," said Liu.

Liu used remote-sensing images, with a resolution of up to 2.5 meters, provided by the French SPOT satellite system, to find the longest headstream of the Indus River.

He also made a field investigation at the source of Indus at the end of September to make sure it contained water, even in the dry season.

It's commonly accepted among the international geographical community that the source of a river is defined as the longest branch in the drainage basin. The source should have water running all through the year.

The Indus river, with a total length of around 3,000 kilometers, runs through China, India and Pakistan. It is the most important source of agricultural irrigation in Pakistan. The river has a total drainage area exceeding 1,165,000 square kilometers. The river's estimated annual flow stands at around 207 cubic kilometers, making it the 21st largest river in the world in terms of annual flow. The ancient Indus civilization was one of the earliest to produce food using agricultural theories in the world.

The upper course of Indus River within Tibet is called Sengge Zangbo, which means a lion-mouthed river. For over 100 years, the source of the river was believed to be found by Sven Hedin in 1907.

Writing in his travelogue, Hedin said he learned from Tibetan monks that the famous river sprung forth from the place called "Mouth of the Lion".At a valley close to Kailash, Sven discovered some small springs which he believed were the source of the Indus river.

"At its foot projects a slab of white rock with an almost horizontal bedding, underneath which several small springs well up out of the ground, forming weedy ponds, and the source stream, which we had traced upwards and which is the first and uppermost of the head-waters of the mighty Indus," he wrote in his travelogue.

"Although the springs found by Sven Hedin were close to the Tibetan legend about the 'Mouth of the Lion', it is not in line with the general standard of what is considered to be the source of a river," said Liu Shaochuang.

But he added that the newly-found source also originated from underground water.

Zhang Jiangqi, director of the archives department of the basic geographical information center under the State Bureau of Surveying and Mapping, said Liu's research updated some very important geographical data.

The bureau will organize experts to examine and verify the result of Liu's research, said Zhang.

(Xinhua News Agency October 21, 2010)