Hai River

Hai River
Name	Hai River
Native name	海河
Caption	The Hai River in Tianjin
Source1 location	Confluence of North Canal, Yongding River, Daqing River, Ziya River, and Grand Canal
Mouth location	Bohai Sea
Subdivision type1	Country
Subdivision name1	China
Length km	70
Basin size km2	318,200
Discharge1 avg	717
Discharge1 location	Mouth
Cities	Tianjin

Hai River. The Hai River is a major waterway in northern China, historically known as the "River of the Capital" due to its critical role for Beijing. It serves as the principal outlet for the Hai River basin, draining a vast region that includes the municipalities of Beijing and Tianjin. The river flows for approximately 70 kilometers from its formation at Tianjin to its mouth in the Bohai Sea.

Geography and Course

The Hai River is a short but hydrologically significant river formed at Tianjin by the confluence of several major tributaries, including the North Canal, the Yongding River, and the Ziya River. From this confluence, it flows east-southeast through the North China Plain before emptying into the Bohai Sea at the Tanggu district. The river's course is heavily engineered, with its lower reaches acting as a crucial tidal channel. The geography of the surrounding Hai River basin is predominantly flat, which has historically contributed to challenges with flooding and water drainage across the region.

History

The Hai River system has been central to the development of northern China for millennia, with its basin being a cradle of early Chinese civilization. During the Ming dynasty and Qing dynasty, the river and its connecting canals, such as the Grand Canal, were vital for transporting grain to the capital, Beijing. In the late 19th and early 20th centuries, the Treaty of Tianjin opened the port of Tianjin to foreign trade, making the Hai River a focal point for international commerce and concessions. Major hydraulic projects, including those initiated in the 1950s under the People's Republic of China, have repeatedly reshaped its course to control floods and manage water resources.

Hydrology and Basin

The Hai River drains an extensive basin of approximately 318,200 square kilometers, encompassing the megacities of Beijing and Tianjin, as well as parts of Hebei province and the Inner Mongolia Autonomous Region. The basin is characterized by a temperate continental monsoon climate with highly variable precipitation, leading to frequent alternations between drought and flood. The average discharge at the mouth is about 717 cubic meters per second, but this fluctuates dramatically. Key hydrological features include large reservoirs like the Guanting Reservoir and the Miyun Reservoir, which regulate flow for water supply and flood control.

Major Tributaries

The Hai River system is fed by five primary tributaries that converge near Tianjin. The northern tributaries include the North Canal and the Chaobai River, which drain waters from Beijing. The Yongding River, often called "Beijing's Mother River," is another critical northern contributor. From the south and west, the system receives flow from the Daqing River and the Ziya River, which themselves have extensive sub-basins. These tributaries are interconnected with the Grand Canal, creating a complex network for water transfer and navigation.

Economic Importance

The Hai River has been an economic artery for northern China for centuries, with the port of Tianjin growing into one of the world's busiest. The river facilitates barge traffic for bulk commodities, supporting industries in the Binhai New Area and beyond. Its waters are crucial for agricultural irrigation across the North China Plain, a major grain-producing region. Furthermore, the basin supports significant industrial activity, including sectors in Tangshan and Shijiazhuang, though this has led to intense competition for water resources between urban, industrial, and agricultural users.

Environmental Issues

The Hai River basin faces severe environmental challenges, primarily due to excessive water extraction, pollution, and ecological degradation. Chronic water scarcity, exacerbated by the demands of Beijing and Tianjin, has led to the over-exploitation of groundwater and the frequent drying up of river channels. Industrial and municipal wastewater discharge has historically caused severe pollution, with efforts like the Huai River and Hai River basins water pollution control plan aiming to improve water quality. Habitat loss and land subsidence are additional critical concerns, prompting large-scale projects like the South–North Water Transfer Project to augment the basin's water supply.

Category:Rivers of China Category:Hai River basin Category:Geography of Tianjin