China’s Sorrow: The Harmful Aspect of the Yellow River
China's two longest rivers, the Yangtze River and the Yellow River, originate in the heights of the Qinghai-Tibet Plateau. They have been essential to agricultural development and population growth throughout China's history. But due to the tremendous drop in altitude from the Qinghai-Tibet Plateau to sea level, water in these rivers flows extremely rapidly and may easily cause flooding. The Yellow River, the world's muddiest river, is especially infamous for its destructive floods.
Since ancient times, the Yellow River has been a mixed blessing for the Chinese people. Like a golden dragon winding across China, the Yellow River nourishes thousands of square miles of fertile soil and is extolled as the cradle of Chinese civilization. In exchange for its benefits, however, the world’s muddiest river extracts a heavy price. One of the most flood-prone rivers in the world, its severe and recurrent flooding has earned the name of China’s Sorrow.
The Yellow River's name refers to the vast quantities of yellow silt, or loess, it carries. Loess is extremely vulnerable to erosion by water. Winding through the Loess Plateau in northwestern China, the raging torrent picks up yellow silt in unusually large amounts and sweeps it downstream. As the river reaches flatter areas the current slows, depositing massive amounts of yellow silt and elevating the riverbed. In the lower reaches of the Yellow River, the riverbed is generally 3-5 meters higher than bilateral ground, and it is even 10 meters higher in some areas. Surprisingly, the Yellow River in this section becomes a watershed, like a ridge of high land, dividing Huai River and Hai River. In rain days, the torrent may easily burst its banks and change the course of the river, causing great destruction.
Over the centuries, the lower reaches of the Yellow River has dramatically changed its courses many times. During the second millennium BC the lower course ran almost northwards. In the next two millennia it swung around little by little like the hands of a clock until, from 1289 to 1324, it was flowing in a southeasterly direction into the center reaches of the Huai River which in turn emptied into the lower Yangzi. Since 1324 it has moved back and forth in an irregular fashion, and at present again debouches north of the Shangdong peninsula.
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Illustration：Sketch of watercourse changes in the lower reaches of the Yellow River
Records indicate that from 602 BC to present, the river's course made at least nine major changes in direction and its levees were breached more than 1,500 times. The mouth of the Yellow River has also moved over the centuries, with the location varying by as much as 800 kilometers.
