Beijing: Bracing to build a number of water projects in Tibet including a dam on Brahmaputra, Chinese scientists have completed a comprehensive satellite study of cross-border Tibetan rivers determining their exact sources besides measuring the length of their drainage basins.

Besides mapping out the course of Brahmaputra, the photographic analysis using expeditions and satellite imagery, the researchers from the Chinese Academy of Sciences (CAS) also collected details about the flow of Indus which flows through India and Pakistan besides Salween and Irrawaddy rivers. Salween and Irrawaddy flows through Burma.

Previously, the sources of four rivers were never clearly designated, and differing accounts regarding their lengths and drainage areas confused researchers for many years due to restrictions of natural conditions and surveying and mapping technologies, Liu Shaochuang, a researcher with the Institute of Remote Sensing Applications under the CAS, said a news agency.

The result of their analysis and field investigations showed that the Brahmaputra River, called Yarlungzangbo in Tibetan language, originates on the Angsi Glacier, located on the northern side of the Himalayas in Burang County of Tibet not Chema-yungdung glacier, which previously identified by geographer Swami Pranavananda in the 1930s, Liu said.

The river is 3,848 km long, and its drainage area is 712,035 square km according to the new findings, while previous documents showed its length varied from 2,900 to 3,350 km and its drainage area between 520,000 and 1.73 million square kms.

The data could be useful in the fifth of round of expert's level talks between India and China to exchange hydrological data and flood management of Brahmaputra.

The study results were announced days after China revealed its plans to build USD 1.8 billion worth of water projects in Tibet, which presumably included hydropower project over Brahmaputra.

The money will go to 16 categories of water programs that cover irrigation, drinking water, flood prevention and control and hydropower, it quoted officials of the Tibet's Water Resources Department said.

According to previous reports, China is planning to build a USD 1.2 billion run of the river dam to generate 510 mw power.

Liu's team found that Indus River, which flows through India but mainly used by Pakistan under the India-Pak water treaty, originates in a valley northeast of Kailash, in Geji County of Tibet.

Its headstream, called Banggokong by local Tibetans, is about 30 kilometers away from Senge Khambab, which Sven Hedin believed was the source of the river more than 100 years ago, Liu said.

The new findings show that the Indus River is 3,600 km long, against previously believed 2,900 or 3,200 km. Its drainage area is more than one million square km.

The four rivers originate on the Qinghai-Tibet Plateau along with the Yangtze, Yellow, Mekong and Ganges rivers, and provide water for about 1.3 billion people, according to Liu.

Liu said the location of the sources of the four rivers will be of great significance for environmental researchers.