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 in southern China. It is formed by the confluence of the

Gui The GUI ( "UI" by itself is still usually pronounced . or ), graphical user interface, is a form of user interface that allows users to interact with electronic devices through graphical icons and audio indicator such as primary notation, inste ...

and Xun Rivers in Wuzhou,

Guangxi Guangxi (; ; alternately romanized as Kwanghsi; ; za, Gvangjsih, italics=yes), officially the Guangxi Zhuang Autonomous Region (GZAR), is an autonomous region of the People's Republic of China, located in South China and bordering Vietnam ...

. It originates from the eastern foot of the Maxiong Mountain in

Qujing Qujing () is a prefecture-level city in the east of Yunnan province, China, bordering Guizhou province to the east and the Guangxi Zhuang Autonomous Region to the southeast; thus, it was called "Key between Yunnan and Guizhou" () and "Throat of Y ...

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 The Pearl River Delta Metropolitan Region (PRD; ; pt, Delta do Rio das Pérolas (DRP)) is the low-lying area surrounding the Pearl River estuary, where the Pearl River flows into the South China Sea. Referred to as the Guangdong-Hong Kong-Ma ...

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 Ph ...

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 pop ...

. 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 inhabitant ...

. The other two main tributaries of Pearl River are the Dong River (literally, the East River) and Bei River (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 An invasive species otherwise known as an alien is an introduced organism that becomes overpopulated and harms its new environment. Although most introduced species are neutral or beneficial with respect to other species, invasive species adv ...

, 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, th ...

Xi River system

The basin of the Xi River ranges from eastern

to southern

Guangdong Province 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) ...

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 The Lingqu () is a canal in Xing'an County, near Guilin, in the northwestern corner of Guangxi, China. It connects the Xiang River (which flows north into the Yangtze) with the Li River (which flows south into the Gui River and Xijiang), a ...

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 ka ...

, which is a tributary of the

Gui River The Gui River (Chinese: 桂江) is a river in the Guangxi Zhuang Autonomous Region of China, and a tributary of the Xi Jiang. It is formed in Pingle by the confluence of the Li River and Lipu River and flows southeast, merging with the Xun Jiang ...

) with the

Xiang River The Xiang River is the chief river of the Lake Dongting drainage system of the middle Yangtze, the largest river in Hunan Province, China. It is the 2nd largest tributary (after Min River) in terms of surface runoff, the 5th largest tribut ...

, 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

to the

Yangtze Valley 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 ...

. 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 Electricity generation is the process of generating electric power from sources of primary energy. For utilities in the electric power industry, it is the stage prior to its delivery ( transmission, distribution, etc.) to end users or its stor ...

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 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 ...

, 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

* Wuzhou *

Foshan Foshan (, ), alternately romanized as Fatshan, is a prefecture-level city in central Guangdong Province, China. The entire prefecture covers and had a population of 9,498,863 as of the 2020 census. The city is part of the western side of the ...

( Gaoming District) * 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 P ...

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 t ...

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 th ...

along with many parts of the river. This increase in population is straining water resources. The climate of the watershed is

subtropical The subtropical zones or subtropics are geographical and climate zones to the north and south of the tropics. Geographically part of the temperate zones of both hemispheres, they cover the middle latitudes from to approximately 35° north a ...

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 An introduced species, alien species, exotic species, adventive species, immigrant species, foreign species, non-indigenous species, or non-native species is a species living outside its native distributional range, but which has arrived there ...

are an issue in rivers in southern China, including the Xi River. Southern China rears the majority of non-native species in

aquaculture Aquaculture (less commonly spelled aquiculture), also known as aquafarming, is the controlled cultivation ("farming") of aquatic organisms such as fish, crustaceans, mollusks, algae and other organisms of value such as aquatic plants (e.g. lot ...

. 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 e ...

. Most introduced species are

omnivore An omnivore () is an animal that has the ability to eat and survive on both plant and animal matter. Obtaining energy and nutrients from plant and animal matter, omnivores digest carbohydrates, protein, fat, and fiber, and metabolize the nu ...

s, including the Nile tilapia, 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 Bisphenol A (BPA) is a chemical compound primarily used in the manufacturing of various plastics. It is a colourless solid which is soluble in most common organic solvents, but has very poor solubility in water. BPA is produced on an industrial ...

, 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 th ...

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 waters, anoxic) processes prevailing, especially in t ...

park protection, develop green

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

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