The Xi River (; ) or Si-Kiang is the western

tributary A tributary, or affluent, is a stream or river that flows into a larger stream or main stem (or parent) river or a lake. A tributary does not flow directly into a sea or ocean. Tributaries and the main stem river drain the surrounding drai ...

of the

Pearl River The Pearl River, also known by its Chinese name Zhujiang or Zhu Jiang in Mandarin pinyin or Chu Kiang and formerly often known as the , is an extensive river system in southern China. The name "Pearl River" is also often used as a catch-a ...

southern China South China () is a geographical and cultural region that covers the southernmost part of China. Its precise meaning varies with context. A notable feature of South China in comparison to the rest of China is that most of its citizens are not n ...

. It is formed by the confluence of the Gui and Xun Rivers in

Wuzhou Wuzhou (, postal: Wuchow; za, Ngouzcouh / Ŋouƨcouƅ), formerly Ngchow, is a prefecture-level city in the east of Guangxi Zhuang Autonomous Region, People's Republic of China. Geography and climate Wuzhou is located in eastern Guangxi borde ...

, Guangxi. It originates from the eastern foot of the Maxiong Mountain in Qujing City,

Yunnan Province Yunnan , () is a landlocked province in the southwest of the People's Republic of China. The province spans approximately and has a population of 48.3 million (as of 2018). The capital of the province is Kunming. The province borders the ...

. Then it flows east through

Guangdong Guangdong (, ), alternatively romanized as Canton or Kwangtung, is a coastal province in South China on the north shore of the South China Sea. The capital of the province is Guangzhou. With a population of 126.01 million (as of 2020) ...

, and enters the Pearl River Delta just east of the Lingyang Gorge in

Zhaoqing Zhaoqing (), alternately romanized as Shiuhing, is a prefecture-level city in Guangdong Province, China. As of the 2020 census, its population was 4,113,594, with 1,553,109 living in the built-up (or metro) area made of Duanzhou, Dinghu ...

. The main branch of the Xi River flows southeast through the delta entering the

South China Sea The South China Sea is a marginal sea of the Western Pacific Ocean. It is bounded in the north by the shores of South China (hence the name), in the west by the Indochinese Peninsula, in the east by the islands of Taiwan and northwestern Phi ...

at Modao Men, just west of

Macau Macau or Macao (; ; ; ), officially the Macao Special Administrative Region of the People's Republic of China (MSAR), is a city and special administrative region of China in the western Pearl River Delta by the South China Sea. With a p ...

. The major cities along the Xi include Wuzhou, Zhaoqing, and

Jiangmen Jiangmen (), alternately romanized in Cantonese as Kongmoon, is a prefecture-level city in Guangdong Province in southern China. As of the 2020 census, its three urban districts, plus Heshan City being conurbated, with 2,657,662 inhabitants a ...

. The other two main tributaries of Pearl River are the Dong River (literally, the East River) and

Bei River Bei River (北江; literally "The North River"; pinyin: ''Běi Jiāng''; wade-giles: ''Pei3 Chiang1''; jyutping: ''Bak1 Gong1'', literally "North River") is the northern tributary of the Pearl River in southern China. The other two main tribu ...

(the Northern River). Other transliterations of the river's name include Hsi River and Hsi Chiang. As for other functions, it plays a vital role in carbon storage and transport in Southern China. The Xi River is facing some ecological challenges such as

drought A drought is defined as drier than normal conditions.Douville, H., K. Raghavan, J. Renwick, R.P. Allan, P.A. Arias, M. Barlow, R. Cerezo-Mota, A. Cherchi, T.Y. Gan, J. Gergis, D. Jiang, A. Khan, W. Pokam Mba, D. Rosenfeld, J. Tierney, an ...

, invasive species, and

pollution Pollution is the introduction of contaminants into the natural environment that cause adverse change. Pollution can take the form of any substance (solid, liquid, or gas) or energy (such as radioactivity, heat, sound, or light). Pollutants, the ...

Xi River system

The basin of the Xi River ranges from eastern

to southern Guangdong Province with a humid subtropical or tropical monsoon climate. The Xi River is navigable for its entire length. It is a commercial waterway of southern China, and links the delta cities to the interior. Over two thousand years ago, the Lingqu Canal was dug, connecting the Xi River basin (the

Li River The Li River or Li Jiang () is the name for the upper reaches of the Gui River in northwestern Guangxi, China. It is part of the Xijiang River system in the Pearl River Basin. The river flows from Xing'an County to Pingle County, where the ...

, which is a tributary of the Gui River) with the

Xiang River The Xiang River is the chief river of the Dongting Lake, Lake Dongting Drainage basin, drainage system of the middle Yangtze, the largest river in Hunan, Hunan Province, China. It is the 2nd largest tributary (after Min River (Sichuan), Min River ...

, which flows into the

Yangtze The Yangtze or Yangzi ( or ; ) is the longest river in Asia, the third-longest in the world, and the longest in the world to flow entirely within one country. It rises at Jari Hill in the Tanggula Mountains (Tibetan Plateau) and flows ...

, thus providing a continuous waterway from the Pearl River Delta to the Yangtze Valley. The Xi River is rich in water conservancy and water resources, providing significant contributions to agricultural

irrigation Irrigation (also referred to as watering) is the practice of applying controlled amounts of water to land to help grow crops, landscape plants, and lawns. Irrigation has been a key aspect of agriculture for over 5,000 years and has been devel ...

, river transportation, and power generation in coastal areas. The Xi River is the largest of the Pearl's tributaries. Its volume of flow is second in China only to that of the

Yangtze River The Yangtze or Yangzi ( or ; ) is the longest list of rivers of Asia, river in Asia, the list of rivers by length, third-longest in the world, and the longest in the world to flow entirely within one country. It rises at Jari Hill in th ...

, and it supplies water to many places in Guangxi, Guangdong and Macau. The greater Xi River is also one of China's longest. Existing in many segments it extends for : *Nanpan River: *Hongshui River: *Qian River: *Xun River: *Xi River (including main branch to the sea):

Major cities along the river

* Foshan (

Gaoming District Gaoming District, formerly romanized as Koming, is an urban district of Foshan, Guangdong, in the People's Republic of China. Gaoming is located west of downtown Foshan and had a population of 420,044 during the 2010 census. It covers an are ...

) * Heshan *

Zhongshan Zhongshan (; ) is a prefecture-level city in the south of the Pearl River Delta in Guangdong province, China. As of the 2020 census, the whole city with 4,418,060 inhabitants is now part of the Guangzhou–Shenzhen conurbation with 65,565,622 ...

Zhuhai Zhuhai (, ; Yale: ''Jyūhói''), also known as Chuhai is a prefecture-level city located on the west bank of Pearl River estuary on the central coast of southern Guangdong province, People's Republic of China, on the southeastern edge of Pear ...

River Ecology

Rivers are a significant storage and transport system for both organic and inorganic carbon. The Xi River is an important source of atmospheric

carbon dioxide Carbon dioxide ( chemical formula ) is a chemical compound made up of molecules that each have one carbon atom covalently double bonded to two oxygen atoms. It is found in the gas state at room temperature. In the air, carbon dioxide is trans ...

in Southern China, with carbon inputs coming mainly from the river's headwater Nanpan and Beipan rivers. In the Beipan River, carbon inputs come from the oxidation of organic carbon and the coal industry along the river. In the Nanpan River, carbon inputs come mainly from soil and organic detritus.

Environmental Issues

Drought

The Xi River basin has historically experienced droughts, which are worsening due to

climate change In common usage, climate change describes global warming—the ongoing increase in global average temperature—and its effects on Earth's climate system. Climate change in a broader sense also includes previous long-term changes to ...

and rapid

urbanization Urbanization (or urbanisation) refers to the population shift from rural to urban areas, the corresponding decrease in the proportion of people living in rural areas, and the ways in which societies adapt to this change. It is predominantly t ...

along with many parts of the river. This increase in population is straining water resources. The climate of the watershed is subtropical to tropical monsoon, with 80% of

precipitation In meteorology, precipitation is any product of the condensation of atmospheric water vapor that falls under gravitational pull from clouds. The main forms of precipitation include drizzle, rain, sleet, snow, ice pellets, graupel and hail. ...

falling between April and September. This extreme variation in yearly precipitation patterns exacerbates drought issues. Climate change is predicted to cause a significant decrease in average, highest, and lowest river flows, with average flow droppings anywhere from 4 to 49%. Increasing frequency and severity lead the meteorological and hydrological droughts.

Invasive species

Invasive or non-native species are an issue in rivers in southern China, including the Xi River. Southern China rears the majority of non-native species in aquaculture. These species are mainly introduced from aquaculture, and may predate or outcompete

native species In biogeography, a native species is indigenous to a given region or ecosystem if its presence in that region is the result of only local natural evolution (though often popularised as "with no human intervention") during history. The term is equ ...

. Most introduced species are omnivores, including the

Nile tilapia The Nile tilapia (''Oreochromis niloticus'') is a species of tilapia, a cichlid fish native to the northern half of Africa and the Levante area, including Israel, and Lebanon. Numerous introduced populations exist outside its natural range. It i ...

, the most common non-native species in southern China rivers.

Pollution

Many commercial fish species in the Xi River and the encompassing Pearl River watershed have been contaminated with significant amounts of Bisphenol A, common in plastics manufacturing. Bisphenol A is a chemical that can be harmful to the

endocrine system The endocrine system is a messenger system comprising feedback loops of the hormones released by internal glands of an organism directly into the circulatory system, regulating distant target organs. In vertebrates, the hypothalamus is the neu ...

of fish and humans.

Protection

In order to protect the Xi River, the Guangxi Zhuang Autonomous Region government issued a notice prohibiting new construction projects and migration of people within the land occupied and inundated areas of the Xi River mainstream control project in Guangxi. Besides, the protection measures include: promulgated a fishing ban,

wetland A wetland is a distinct ecosystem that is flooded or saturated by water, either permanently (for years or decades) or seasonally (for weeks or months). Flooding results in oxygen-free (anoxic) processes prevailing, especially in the soils. The p ...

park protection, develop green

recycling Recycling is the process of converting waste materials into new materials and objects. The recovery of energy from waste materials is often included in this concept. The recyclability of a material depends on its ability to reacquire the p ...

and low-carbon economic, the innovation of ecological and

environmental protection Environmental protection is the practice of protecting the natural environment by individuals, organizations and governments. Its objectives are to conserve natural resources and the existing natural environment and, where possible, to repair dam ...

cooperation mechanism and Xi River Basin Nature Reserve construction management.

References

External links

WWF - Xi Jiang Rivers and Streams Ecoregion
{{Coord, 22.0602, N, 113.4792, E, source:wikidata-and-enwiki-cat-tree_type:river_region:CN-44, display=title Tributaries of the Pearl River (China) Rivers of Guangdong Rivers of Guangxi