Yellow River

Yellow River (Huang He, Huang Jiang)
Course of the Yellow River with major cities
Origin	Bayan Har Mountains, Qinghai Province
Mouth	Bohai Sea
Basin countries	China
Length	5464 km (3398 mi)
Source elevation	4500 m (14,765 ft)
Avg. discharge	2,571 m³/s (90,808 ft³/s)
Basin area	752 000 km²

The Yellow River or Huang He (Chinese: 黃河; pinyin: Huáng Hé; sometimes simply called 河 Hé ("The River") in ancient Chinese; Mongolian: Hatan Gol, Queen river) is the second-longest river in China (after the Yangtze River) and the sixth-longest in the world at 5,464 kilometers (3,398 mi). Originating in the Bayan Har Mountains in Qinghai Province in western China, it flows through nine provinces of China and empties into the Bohai Sea. The Yellow River basin has an east-west extent of 1900 km (1,180 mi) and a north-south extent of 1100 km (684 mi). Total basin area is 752,443 km² (290,520 mi²).

The Yellow River is called "the cradle of Chinese civilization", as its basin is the birthplace of the northern Chinese civilizations and is the most prosperous region in early Chinese history. But frequent devastating flooding, largely due to the elevated river bed in its lower course, has also earned it the unenviable name "China's Sorrow".

Name

Early Chinese literature refers to the Yellow River simply as He (河), or "River". The first appearance of the name "Yellow River" (黄河) is in the Book of Han (漢書) written in the Western Han dynasty (206 BC–AD 9). The name "Yellow River" describes the perennial ochre- yellow colour of the muddy water in the lower course of the river. The yellow colour comes from loess suspended in the water.

Sometimes the Yellow River is poetically called the "Muddy Flow" (Chinese: 濁流; pinyin: Zhuó Liú). The Chinese expression "when the Yellow River flows clear" is similar to the English expression "when Hell freezes over."

History and culture

Traditionally, it is believed that the Chinese civilization originated in the Yellow River basin. The Chinese refer to the river as "the Mother River" and "the Cradle of the Chinese civilization".

During the long history of China, the Yellow River has been considered a blessing as well as a curse and has been nicknamed both "China's Pride" (中国的骄傲 Zhōngguó de Jiāo'ào) and "China's Sorrow" (中国的痛 Zhōngguó de Tòng). Records indicate that, from 602 BC to present, the river's course underwent at least 5 large-scale changes, and its levees were breached more than 1,500 times. A major course change in 1194 took over the Huai River drainage system throughout the next 700 years. The mud in the Yellow River literally blocked the mouth of the Huai River and left thousands homeless. The Yellow River adopted its present course in 1897 after the latest course change occurred in 1855. Currently, the Yellow River flows through Jinan, capital of the Shandong province, and ends in the Bohai Sea, yet the eastern terminus for the Yellow River has oscillated from points north and south of the Shandong Peninsula in its many dramatic shifts over time.

The river gets its yellow colour mostly from the fine-grained calcareous silts which originate in the Loess Plateau and are carried in the flow. Centuries of silt deposition and diking has caused the river to flow above the surrounding farmland, making flooding a critically dangerous problem. Flooding of the Yellow River has caused some of the highest death tolls in world history, with the 1887 Huang He flood killing 900,000 to 2,000,000 and the 1931 Huang He flood killing 1,000,000 to 4,000,000. In 1938, during the Second Sino-Japanese War, the Nationalist troops under Chiang Kai-Shek broke the levees holding back the river in order to stop the advancing Japanese troops. The river at that time flooded a huge area and took some 500,000 to 900,000 lives including a number of advancing Japanese soldiers.

Another historical source of devastating floods is the collapse of upstream ice dams in Inner Mongolia with an accompanying sudden release of vast quantities of impounded water. There have been 11 such major floods in the past century, each causing tremendous loss of life and property. Nowadays, explosives dropped from aircraft are used to break the ice dams before they become dangerous.

Some of the known flood defenses used in ancient times were ditches, walls (dams), levees, and rebound channels to route floodwaters around a blockage. But the solutions were merely local, and sometimes the dams were too small and weak. If the river broke down the defenses it caused far more damage than if none had been built.

Characteristics

The Yellow River is notable for the large amount of silt it carries—1.6 billion tons annually at the point where it descends from the Loess Plateau. If it is running to the sea with sufficient volume, 1.4 billion tons are carried to the sea annually.

In modern times, since 1972 when it first dried up, the river has dried up in its lower reaches many times, from Jinan to the sea in most years, in 1997 for 226 days. The low volume is due to increased agricultural irrigation, by a factor of five since 1950. Water diverted from the river as of 1999 served 140 million people and irrigated 74,000 km² (48,572 mi²) of land. The highest volume occurs during the rainy season, from July to October, when 60% of the annual volume of the river flows. Maximum demand for irrigation is needed between March and June. In order to capture excess water for use when needed, and for flood control and electricity generation, several dams have been built, but due to the high silt load their life is expected to be limited. A proposed South-North Water Transfer Project involves several schemes to divert water from the Yangtze River, one in the western headwaters of the rivers where they are closest to one another, another from the upper reaches of the Han River, and a third using the route of the Grand Canal.

Due to its heavy load of silt the Yellow River is a depositing stream, that is, it deposits part of its carried burden of soil in its bed in stretches where it is flowing slowly. These deposits elevate the riverbed which flows between natural levees in its lower reaches. Should a flood occur, the river may break out of the levees into the surrounding lower flood plain and adopt a new course. Historically this has occurred about once every hundred years. In modern times, considerable effort has been made to strengthen levees and control floods.

The Yellow River delta totals 8,000 square kilometers (3,090 mi²). However, since 1996 it has been reported to be shrinking slightly each year through erosion.

Geography

From its sources, Gyaring Lake and Ngoring Lake high in the Bayan Har Mountains in Qinghai Province in the far west of China, the Yellow River loops north, bends south, creating the "Great Bend", and then flows generally eastward across northern China to the Gulf of Bohai, draining a basin of 752,443 km² (290,520 mi²) which nourishes 120 million people.

The river is commonly divided into three stages. However, different scholars have different opinions on how the three stages are divided. This article adopts the division used by the Yellow River Conservancy Commission.

Upper reaches

The upper reaches of the Yellow River constitute a segment starting from its source in the Bayan Har Mountains and ending at Hekou County of Inner Mongolia just before it turns sharply to the north. This segment has a total length of 3,472 km (2,160 mi) and total basin area of 386,000 km² (149,035 mi²), 51.3% of the total basin area. Along this length, the elevation of the Yellow River drops 3496 metres, with an average drop of 0.1%.

The source section flows mainly through pastures, swamps, and knolls between the Bayan Har Mountains and the Anemaqen ( Amne Machin) Mountains. The river water is clear and flows steadily. Crystal clear lakes are characteristic of this section. The two main lakes along this section are Lake Bob (扎陵湖) and Lake Eling (鄂陵湖), with capacities of 4.7 billion and 10.8 billion m³, respectively. At elevations over 4,260 m (13,976 ft) above sea level they are the largest two plateau freshwater lakes in China.

The valley section stretches from Longyang Gorge in Qinghai to Qingtong Gorge in Gansu. Steep cliffs line both sides of the river. The water bed is narrow and the average drop is large, so the flow in this section is extremely turbulent and fast. There are 20 gorges in this section, the most famous of these being the Longyang, Jishi, Liujia, Bapan, and Qingtong gorges. The flow conditions in this section makes it the best location for hydroelectric plants.

After emerging from the Qingtong Gorge, the river comes into a section of vast alluvial plains, the Yinchuan Plain and Hetao Plain. In this section, the regions along the river are mostly deserts and grasslands, with very few tributaries. The flow is slow. The Hetao Plain has a length of 900 km (560 mi) and width of 30 to 50 km (20–30 mi). It is historically the most important irrigation plain along the Yellow River.

Middle reaches

The part of Yellow River between Hekou County in Inner Mongolia and Zhengzhou in Henan constitutes the middle reaches of the river. The middle reaches are 1,206 km (749 mi) long, with a basin area of 344,000 km² (132,820 mi²), 45.7% of the total, with a total elevation drop of 890 meters (2,920 ft), an average drop of 0.074%. There are 30 large tributaries along the middle reaches, and the water flow is increased by 43.5% on this stage. The middle reaches contribute 92% of the river's silts.

The middle stream of the Yellow River passes through the Loess Plateau, where substantial erosion takes place. The large amount of mud and sand discharged into the river makes the Yellow River the most sediment-laden river in the world. The highest recorded annual level of silts discharged into the Yellow River is 3.91 billion tons in 1933. The highest silt concentration level was recorded in 1977 at 920 kg/m³. These sediments later deposit in the slower lower reaches of the river, elevating the river bed and creating the famous "river above ground". In Kaifeng, the Yellow River is 10 meters (33 ft) above the ground level.

From Hekou County to Yumenkou, the river passes through the longest series of continuous valleys on its main course, collectively called the Jinshan Valley. The abundant hydrodynamic resources stored in this section make it the second most suitable area to build hydroelectric power plants. The famous Hukou Waterfall is in the lower part of this valley.

Lower reaches

In the lower reaches, from Zhengzhou to the sea, a distance of 786 km (488 mi), the river is confined to a levee-lined course as it flows to the northeast across the North China Plain before emptying into the Bohai Sea. The basin area in this stage is only 23,000 km² (8,880 mi²), 3% of the total. The total drop in elevation of the lower reaches is 93.6 m (307 ft), with an average drop of 0.012%.

The silts received from the middle reaches form sediments here, elevating the river bed. During 2,000 years of levee construction, excessive sediment deposits have raised the riverbed several meters above the surrounding ground. Few tributaries add to the flow in this stage; nearly all rivers to the south drain into the Huai River, whereas those to the north drain into the Hai River.

Tributaries

Tributaries of the Yellow River include:

• White River (白河)
• Black River (黑河)
• Huang River (湟水)
• Zuli River (祖厉河)
• Qingshui River (清水河)
• Dahei River (大黑河)
• Kuye River (窟野河)
• Wuding River (无定河)
• Fen River (汾河)
• Wei River (渭河)
• Luo River (洛河)
• Qin River (沁河)
• Dawen River (大汶河)

Hydroelectric power dams

Below is the list of hydroelectric power stations built on the Yellow River (in bracket is the year to start operation):

• Sanmen Gorge hydroelectric power station (1960)
• Sanshenggong hydroelectric power station (1966)
• Qingtong Gorge hydroelectric power station (1968)
• Liujia Gorge hydroelectric power station (1974)
• Yanguo Gorge hydroelectric power station (1975)
• Tianqiao hydroelectric power station (1977)
• Bapan Gorge hydroelectric power station (1980)
• Longyang Gorge hydroelectric power station (1992)
• Da Gorge hydroelectric power station (1998)
• Li Gorge hydroelectric power station (1999)
• Wanjiazhai hydroelectric power station (1999)
• Xiaolangdi hydroelectric power station (2001)

Provinces and cities

Originating in the Bayan Har Mountains, the Yellow River passes through seven provinces and two Autonomous Regions, namely Qinghai, Sichuan, Gansu, Ningxia, Inner Mongolia, Shaanxi, Shanxi, Henan, and Shandong. The mouth of the Yellow River is located at Dongying, Shandong.

The provinces of Hebei and Henan derive their names from the Huang He. Their names mean respectively "north of the (Yellow) River" and "south of the (Yellow) River".

Major cities located along the Yellow River include, starting from the source, Lanzhou, Wuhai, Baotou, Kaifeng, and Jinan.

Crossings

• Binzhou Yellow River Highway Bridge
• Sunkou Yellow River Highway Bridge
• Zhongshan Bridge

Flooding and changes of course

The river is extremely prone to flooding. It has flooded 1,593 times in last 3,000–4,000 years, while its main course changed 18 times. Historical maps from the Qin Dynasty indicate the Yellow River was then flowing considerably north of its present course. Those maps show that after the river passed Luoyang it flowed along the border between Shanxi and Henan provinces, continuing along the border between Hebei and Shandong before emptying into Bohai Bay near present-day Tianjin.

Beginning in 1194, the part of the Yellow River flowing to the north changed its course southward by running into the Huai River. The course of the river has changed back and forth between the route of the Huai River and the original route of the Yellow River several times over the past 700 years. The consequent buildup of silt deposits was so heavy that the Huai River was unable to flow in its historic course after the Yellow River reverted to its northerly course for the last time in 1897. Instead, the water pools up into Hongze Lake and then runs southward toward the Yangtze River.

Floods on the river account for some of the deadliest natural disasters ever recorded. The flatness of North China Plain contributes to the deadliness of the floods. A slight rise in water level means a large portion of land is completely covered in water. When a flood occurs, a portion of the population initially dies from drowning, then by the spread of diseases and the ensuing famine.

• In 1887 the river flooded the North China Plain causing an estimated 900,000–2,000,000 deaths.
• In 1931 the river flooded the North China Plain causing an estimated 1,000,000–4,000,000 deaths.

In 1938, during the Second Sino-Japanese War, the Nationalist troops under the orders of Chiang Kai-Shek broke the dike holding back the Yellow River in order to stop the advancing Japanese troops. This resulted in the flooding of an area covering 54,000 km² and the deaths of 500,000–900,000 people.

Several dams and flooding projects have been constructed along the Yellow River preventing any further flooding of the river.