Huang

I

Introduction

Huang or Yellow River, also Hwang Ho, second-largest river in China, with a total length of about 5,464 km (3,395 mi). The Huang He (“he” means river in Chinese) rises in northern China in a series of springs and lakes in the Kunlun Mountains in Qinghai (Ch'ing-hai) Province, south of the Gobi Desert. The river gets its name from the enormous amount of silt it carries, giving the water a distinctive yellow colour.

II

Course of the Huang

From its source, the river first flows east through deep gorges and then turns north-east at the city of Lanzhou (Lanchow) in Gansu (Kansu) Province, from which point it flows for many hundreds of kilometres through the Ordos Desert, south of the Gobi. Turning east, the river then flows due east for about 320 km (200 mi). It then turns due south, flowing swiftly through a young valley cut in deposits of very fine-grained and easily eroded loamy soil known as loess between Shaanxi (Shensi) and Shanxi (Shansi) provinces.

In this portion of its course, the river picks up and carries in suspension the yellow silt that gives it its name. The load of sediment is increased by the loess carried into the main stream by a number of tributaries, including the Fen He (Fen Ho) and the Wei He (Wei Ho). The Wei He enters the Huang in the central portion of Shaanxi, and the river then flows east across the northern portion of Henan (Honan) Province to the plains of northern China.

The Huang has changed course in the eastern portion, nearer the sea, a number of times. For several centuries before 1852, it emptied into the Yellow Sea, south of the highlands of Shandong (Shantung) Province. The course shifted north that year, and, from that time until 1938, the river emptied into Bo Hai (Po Hai), also known as the Gulf of Zhili (Chih-li). In 1938, during the Sino-Japanese War, the Chinese forces, seeking to impede the invading Japanese, destroyed the dykes near Kaifeng and diverted the Huang to the old bed. The Chinese rebuilt the dykes in 1946-1947, rediverting the river to the Bo Hai. In 1955 the Chinese government initiated a programme of works on the Huang to construct hydroelectric dams and flood control measures.

III

Flooding

At the city of Kaifeng (K'ai-feng), the river enters the plains and changes from a torrent to a meandering stream with a broad channel enclosed by dykes. The dykes were built over a period of centuries to control the river and prevent floods, but they have actually had the opposite effect. Because the large amount of sediment carried by the stream has silted up the bottom of the riverbed, the level of the river has risen, necessitating the construction of higher and higher dykes. If the dykes had not been built, the silt would have been deposited in the floodplain outside the riverbed. As a result, in many portions of its lower, or east, course the river is as much as 21 m (70 ft) above the surrounding plain, and when the river level rises, disastrous floods occur.

The deforestation of the mountains in the upper part of the course of the river has increased the run-off and thus increased the flood heights. The floods of the Huang have been so frequent and devastating that the river is often called China's Sorrow. The worst in the history of the river, and probably the worst globally in modern times, occurred in 1931. Between July and November, some 88,060 sq km (34,000 sq mi) of land were completely submerged, and a further 20,720 sq km (8,000 sq mi) were partially flooded. About 80 million people were reported homeless, and about 1 million died in the flood itself and in the famines and epidemics that followed. A recent catastrophic flooding occurred in 1998, with more than 3,500 people drowned and about 7 million dwellings destroyed.

In August 2001, the Asian Development Bank approved a US$150 million loan to China to implement an integrated flood control system in the lower reaches of the Huang. The system aims to improve the environmental quality of the area by rebuilding river embankments and constructing elevated platforms near endangered settlements, as well as the planting of trees and grasses to reverse deforestation in the region. The project is also designed to include early warning systems and better flood forecasting, and is expected to be completed by the end of 2005.