User:JackJiangZZ/Xi River

The Xi River or West River (Chinese: 西江) is the main river of the Pearl River Watershed. It originates from the eastern foot of the Maxiong Mountain in Qujing City, Yunnan Province. The total length of Xi River is around 2075 kilometers, and a drainage area is 353120 square kilometers.

The basin of the Xi River ranges from eastern Yunnan Province to southern Guangdong Province with a humid subtropical or tropical monsoon climate. The Xi River is rich in water conservancy and water resources, providing significant contributions to agricultural irrigation, river transportation, and power generation in coastal areas.

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, invasive species , and pollution. Fortunately, government has set up some policies and plans to protect the Xi River.

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 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.

Drought
The Xi River basin has historically experienced droughts, which are worsening due to climate change and rapid urbanization 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 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. Most introduced species are omnivores, including the Nile tilapia, the most common non-native species in southern China rivers.

Pollution
Due to heavy industry and development along many reaches in the watershed, soil in the Xi River basin is contaminated with heavy metals, primarily Cadmium. Most of the watershed is not fit for raising crops, as Cadmium is carcinogenic. However, agriculture does take place along the river, and soil sediments are severely contaminated with other heavy metals, especially near urban centers. This contamination is from untreated urban wastewater and industrial effluent being disposed of in the river. 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 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 park protection,  develop green recycling and low-carbon economic, the innovation of ecological and environmental protection cooperation mechanism and Xi River Basin Nature Reserve construction management.