Red River (Asia)
Template: Infobox River / Obsolete
The Red River (Chinese红河/红河, Pinyin Hong He and Vietnamese Sông Hồng or Hồng Hà ) or Yuan Jiang (Chinese元 江, pinyin Yuanjiang ) is a river system in southern China and northern Vietnam.
- 4.1 history
- 4.2 Economics
- 4.3 Environment
Geography and Geology
The total length of the river is 1149 km; of which 639 km on the territory of the People's Republic of China and 510 km on the territory of the Socialist Republic of Vietnam. This length varied geological strong, for example, the sea level was higher by 5 to 6 meters approximately 4000 years ago, so that the mouth to the west of Hanoi was ( Higham 1989).
The always significant amount mitgeschwemmter sediments has greatly increased through deforestation, intensive cultivation and high soil erosion in the catchment area in recent years and is currently about 10 million tonnes per year, ie 1.5 kg per cubic meter of water. The soil has a strong order result, as well as a growth of the delta by about 100 m per year. The Red River is also infamous for the strong seasonal fluctuations in water quantity and its violent floods.
These circumstances forced the Vietnamese since the eleventh century to contain the river system with levees, the / s are designed today to a water supply 49000-57000 m³. The highest ever value of 37,000 m³ / s was measured in 1945. Meanwhile, the embanked river bed is mostly higher than the surrounding countryside. The maximum tidal range along the coast of the delta is approximately 4 m. If predictions of the IPCC are true with respect to the rising of the sea level, is the entire Delta, which is only slightly between 1 m and 3 m above sea level, at risk.
The by the entrained sediments, inter alia, Iron oxide, a reddish- brown colored water gives the river its name.
- Earlier in German transliteration also
Source and upper reaches
The Red River rises in the northern part of the southern Chinese province of Yunnan in 1776 m height. The headwaters is a mountain range southwest of the city of Dali in the same autonomous district. The overflow has washed the river valleys to deep gorges. In a southeasterly direction fluent crosses the Red River autonomous territories of Dai peoples ( here mainly Yi, Hani and Miao ) into the Honghe Autonomous Prefecture. The term Hong He for the river was eponymous for the district.
In the city Lào Cai province, Vietnam in Lào Cai River transgresses the boundary and reaches the large landscape Tonkin ( Vietnamese Bắc Bo, " northern boundary "). The Vietnamese call the section of the river from here to Việt Trì also Sông Thao.
In Yen Bai, the river enters the North Vietnamese lowlands. The main tributary of Black River ( Sông Da ) also rises in Yunnan and runs south parallel to Sông Hồng. Between Tam Thanh Việt Trì in the province of Phú Thọ it flows into the main river. From Việt Trì the Red River is navigable. There, the second major tributary, the Clear River ( Sông Lô ), coming from the north flows. The section from here to Hanoi is also called Nhi Ha. At Sơn Tây over the river flows southeast through the capital Hanoi.
The Red River Delta
Main article: Dong Bang Song Hong
120 km off the coast, east of Hanoi towards the town Thuận Thành, the river divides into two main runs to the north weiterzufließen as Sông đường south as Sông Hồng. From here, the Red River widens to its mouth in the Gulf of Tonkin to a delta with an area of approximately 22,000 km ². The Delta gives its name to the Vietnamese Region " Red River Delta " ( Dong Bằng Sông Hồng ).
On a northern tributary of the Song Cua Duong named Cam ( Forbidden Door ) is Haiphong, the principal seaport of North Vietnam. South of Nam Định joins the main flow of the river into the Gulf of Tonkin ( Vietnamese Vinh Bắc Bo, Chinese北部 湾Beibu Wan ).
Provinces and districts
Chinese districts of Yunnan Province, located in the catchment area of the Red River:
Dali, Pu'er City, Chuxiong, Yuxi City, Honghe, Wenshan
Lào Cai, Yen Bai, Phu Tho, Vinh Phúc, Hà Nội, Hưng Yên, Ha Tay, Nam Định, Hà Nam, Thái Bình
The Delta is the region of origin of the people of the Kinh. With 15 % of the Vietnamese population, the region is one of the most densely populated in the world.
The legend, the Red River was suitable in contrast to the Mekong River, navigable to the upper reaches, and thus to trade with China, influenced in the 19th century the interest of France to North Vietnam (see also: Vietnam under French colonial rule ).
During the Vietnam War, the region was heavily bombed.
In the middle reaches, there are several significant hydropower stations, whose performance decreases continuously by the landing of the riverbed.
The Delta with its fertile sediment deposits is a major area of agricultural production in Vietnam. About 47 % of the area ( 820 800 ha) is agricultural land, is grown on more than a third of the rice production of the country. The irrigation and drainage is done by an ingenious system of dams, dikes and canals. The total length of the base up to 40 m wide dikes today, is more than 3000 km, on the crowns often run traffic routes.
The delta of the Red River was admitted in 2004 as a Biosphere Reserve in the MAB program of UNESCO. With the hazards of the river system and its delta deal various multinational commissions, the project Flocods ( Flood Control Decision Support ).