The Duilong River, or Duilong Qu (Tibetan: Toelung; ), is a right tributary of the

Lhasa River The Lhasa River, also called Kyi Chu (, ), is a northern tributary of the Yarlung Tsangpo River in the south of the Tibet Autonomous Region of China. The Yarlung Tsangpo is the upper section of the Brahmaputra River. The Lhasa River is subject to ...

, which it enters just below the city of

Lhasa Lhasa (; Lhasa dialect: ; bo, text=ལྷ་ས, translation=Place of Gods) is the urban center of the prefecture-level city, prefecture-level Lhasa (prefecture-level city), Lhasa City and the administrative capital of Tibet Autonomous Regio ...

, Tibet, China. The river is about in length. Water quality may be compromised by dissolved substances including arsenic from geothermal springs.

Course

The Duilong is the largest tributary of the Lhasa River, with a length of and a basin area of . The valley of the Duilong River leads south to the Lhasa River, and is contained by two ridges of the Nianqing Tanggula Mountains. The Duilong has hydro-electrical power generation capacity of 4,000 KW. The non-monsoon season lasts from October to May each year, and the monsoon season from June to October. 80% of the precipitation is in the monsoon season, when warm and moist air is transported to the Tibet Plateau from the south Indian Ocean. The Qinghai–Tibet Railway approaches Lhasa from the northwest. It descends from the

Amdo Amdo ( �am˥˥.to˥˥ ) is one of the three traditional Tibetan regions, the others being U-Tsang in the west and Kham in the east. Ngari (including former Guge kingdom) in the north-west was incorporated into Ü-Tsang. Amdo is also the bi ...

grasslands to Nagchu and Damshung, and then follows the Toelung River from Yangpachen through Toelung Dechen county into west Lhasa. A new railway bridge was built over the

river to link the station in Liuwu township on the south side of the river to central Lhasa on the north side.

Water quality

The southern Tibetan Plateau is tectonically active, and contains many geothermal springs. Although rivers in Tibet are generally considered to be clean, the water of the Duilong is affected by these springs. A 2015 study reported that during the non-monsoon season the levels of

arsenic Arsenic is a chemical element with the symbol As and atomic number 33. Arsenic occurs in many minerals, usually in combination with sulfur and metals, but also as a pure elemental crystal. Arsenic is a metalloid. It has various allotropes, but ...

in the river, at 205.6 μg/L were higher than the

WHO Who or WHO may refer to: * Who (pronoun), an interrogative or relative pronoun * Who?, one of the Five Ws in journalism * World Health Organization Arts and entertainment Fictional characters * Who, a creature in the Dr. Seuss book '' Horton He ...

guideline of 10 μg/L for drinking water. The source of the pollution seems to be untreated water from the

Yangbajain Geothermal Field The Yangbajain Geothermal Field (羊八井地热田) is a geothermal field near the town of Yangbajain in Damxung County, Tibet Autonomous Region, China. The fluid is heated by magmatic activity not far below the surface. It is a tourist attraction ...

power station. It can be detected downstream from this site.

Yangjinshi Reservoir

A 1995 paper concluded that proposed Yangjinshi Reservoir would provide a good balance between the conflicting demands for irrigation and hydroelectric power generation. It could not be built in the lower reaches, where the river is paralleled by the Qinghai-Xizang Road, or in the middle reach where it would cover the Yangbajain geothermal field. The chosen location was therefore upstream, controlling a catchment area of with an annual normal runoff of . If the water level were maintained at above sea level, the reservoir would have a capacity of including available storage of . The project would include a 4500 kW power station.

References

Sources

* * * * * * {{refend Rivers of Lhasa Tributaries of the Brahmaputra River Doilungdêqên District Damxung County