Flood in the Yellow River, China, 1887

Throughout China’s history, on both of its major rivers, flooding has always been a common experience. This has been especially true on the Yellow River, locally known as the Huanghe, because of the large volume of loess silt that it carries. This kind of light silt can easily be dislodged from the side of the river and carried along by the stream. At the lower reaches of the river, where the land is relatively flat the speed of the river decreases, much of the silt is deposited. The dykes on both sides of the river were originally built to prevent river overflows that would destroy the farmlands, the only source of livelihood for the peasants who own and work the farms. From time to time, however, sudden heavy rainfall can make the river overtop these dykes and flood the neighboring farms. That is what happened in 1887 when the worst flood in Chinese history occurred. The Yellow River overtopped its dikes in Henan Province in the lower reaches of the river. Five thousand square miles were flooded. Eleven large cities and hundreds of villages were destroyed. 900,000 people killed, and two million were homeless. “River of Sorrow” is another name that has been given to the Hwanghe and it is easy to understand why.

The process by which a catastrophic flood occurs is tied to both the amount of silt and the height of the dykes. Throughout most of its history, the Huanghe was not dredged so there was always a slow buildup in the level of the river compared with the surrounding land. Earthen dykes sup-ported by stones were built on the sides of the river and periodically raised to higher levels as the river rose so that river water was always below overtop level. Thus, in the thousands of years over which farming was carried on beside the river, the overall picture was of a river flowing along at a high level above the adjacent land. When the river overtopped its banks the damage caused was enormous because of the advantage of height. The kinetic energy in the water leaving the river enabled it to wash away large segments of the dykes. The overflow of water then continued until it reached the lowest point in the broken dykes. It took some time for the water to drop to this level and then the hard manual work of rebuilding the dykes had to be undertaken.