The Cause and Prevention of Floods in China
鄔永成 / Allen Yong-Cheng Wo
中華文化中心中文學校/Chinese Community Center, TX
In the spring and summer of 1998, high waters overflowed the banks of many
Chinese rivers, flooding the surrounding villages and farmlands. Millions were affected
by this catastrophe, which ravaged through most of the Chinese plains. A flood is a
high flow of water that breaches the normal confinements or covers land that is normally
dry. The specific type of flood that devastated the Chinese countryside is the river flood;
these floods are caused by high or overflowing water from a river and typically occur
after spring rains or snow melts. Floods are one of the most calamitous of all natural
disasters; they are among the most costly in terms of human hardship and economic
loss and the most frequent. The extreme calamity caused by floods is due to the weight
of water; a cubic yard weighs three quarters of a ton. Thus, water exerts a tremendous
force, especially when it is captured in a channel, where its intensity can be
concentrated.
The 1998 floods were responsible for the deaths of over three thousand people
in China. One human rights group estimated that over a thousand people were missing.
The floods affected more than two hundred thirty million people, a fifth of the population.
An estimated five million houses and forty-four thousand schools were damaged or
obliterated; over twenty-one hectares of land have been swamped. Transportation,
telecommunications, and electrical connections were disrupted. Many dikes were
overwhelmed by torrents of water. Economic losses have exceeded twenty billion US
dollars. The water levels of the major Chinese rivers were well over the danger mark
for most of the summer months. The Yangtze River floods were the worst since 1954,
when thirty thousand people were killed. In northeastern China, the Nen and Songhua
rivers rose to record highs. Flooding of the major rivers in the Tibet has affected eighty
thousand people in forty of Tibet’s counties. The disintegration of some of the Nen
River dikes near the city of Daquing, China’s largest oil field, closed over a thousand five
hundred oil wells and forced thousands of people to evacuate. The oil wells of Daquing
produce about a third of China’s oil. Other major Chinese industrial and urban centers
were also at risk throughout the flood season. Homeless families were finding refugee
in makeshift plastic tents and in shelters constructed of plastic bags and straw atop dikes.
There was little food, and clean water was almost nonexistent. Colds, respiratory
infections, and other minor illnesses were a problem; however, the strenuous efforts of
medical teams prevented an outbreak of epidemics. Forty million dollars in relief funds
was designated by Beijing to help the victims overcome the devastation. The
International Federation of Red Cross in the form of food, medicine, and water
purification supplies also provided aid. The majority of the contributions went to families
in the five most devastated regions: Jiangxi, Fujian, Guangxi, Hunan, and Sichuan.
Floods have played important roles in China’s long history. Early floods
deposited the silt carried by rivers, forming vast, fertile plains. It was on these alluvial
plains where the Chinese civilization originated. The cradle of civilization was the North
China Plain, formed over millions of years from the loess deposits of the Yellow River
floods. The Yellow River’s name is due to the presence of loess, a fertile yellow colored
soil. The early Chinese farmers realized richness of the loess soil and the cultivated
their crops on the banks of the Yellow. However, the famine and destruction caused by
subsequent floods earned the Yellow River another name, China’s Sorrow. Attempts to
tame the Yellow River have been made throughout China’s history. Over four thousand
years ago, an emperor named Yu conquered the river by deepening the channel through
dredging and by digging diversion canals to relieve the main stream of its heavy flow.
Later, Yu’s flood control methods were abandoned in favor of rituals and the ceaseless
building of dikes. Maidens were flung into the raging floodwaters as sacrifices to
appease the river god. In other areas, priests and officials were sacrificed too. Dikes
were built by villages and individuals intent on protecting their own property. During the
Han Dynasty, dike building was unified under a central authority. Dike design was
refined and labor was organized more efficiently; as a result, flood control was improved.
China’s other major river, the Yangtze, also created problems for the early Chinese;
however, it is not as heavily laden with silt or as flood prone as the Yellow River. A
major deluge occurs at an average of every ten years. The flood control of these two
major rivers has been a top priority of the Chinese since the beginning of the Chinese
civilization.
Even with modern flood control technology, floods continued to threaten
China’s countryside. In the spring of 1887, the Yellow River overflowed its banks and
turned China’s northern provinces into swamps. Over two thousand towns, villages,
and cities were engulfed by the rising waters and destroyed. Somewhere between two
million and seven million people lost their lives during the 1887 flood season. Famine
and epidemics contributed to the hardships from the floods. In September 1911, the
Yangtze River flooded the many southeastern Chinese provinces after a spring and
summer of heavy rains. More than two hundred thousand people died, and over half a
million were left homeless. The Yellow River flood of 1935 inundated the North China
Plain, killing thirty thousand people and rendering five million homeless. The damage
caused by the flooding was estimated at three hundred million dollars. The Yellow
River flooded again in 1938; perhaps the most disastrous of the twentieth century, it was
manmade. With the Japanese troops advancing, Chiang Kai-shek destroyed the
Yellow River Dike at Huayuankou in attempt to annihilate the invaders. The effect was
not the desired one; the Japanese were detained for only three months while nine
hundred thousand Chinese died. Two months of rain during the spring of 1948 caused
the Min River to overflow in early August, inundating eighty percent of the Fukien
Province. A thousand people died and a million were left homeless. In August 1950,
the Yangtze and Hwai rivers flooded much of eastern China. Five hundred people
drowned and ten million people were made homeless. The Yangtze and Hwai flooded
again in 1954. The result was more extreme this time; the flood evicted a million people
and killed forty thousand. Deforestation in the upper reaches of the Yangtze caused
floods of 1981 that killed over seven hundred people and evicted over a million people;
approximately thirty thousand people were missing. The Xi Jiang River flooded in May
1982 when twenty-four inches of rain fell in thirteen hours on the province of Guangdong.
Over four hundred people drowned and about half a million were rendered homeless.
Floods have claimed billions of lives and left even more people homeless throughout the
course of China’s history.
There are many factors contributing to the flooding in China. In the spring and
summer the Asian monsoon winds sweep rain clouds from the oceans toward China,
where the rain falls. The seasonal floods afflicting China every summer are caused by
the monsoon. The Chinese have been able to control these normal yearly floods by
building dikes along the major rivers in flood prone areas. During the past year,
however, the rains began earlier and were heavier than usual, and the Chinese dikes
were not prepared nor properly fortified to withstand the tremendous downpour. Some
government officials even suggested that El Nino might have also had an effect on the
amount of rain that China received the past summer. Furthermore, the Chinese rush
toward industrialization and economic modernization has indirectly contributed to the
severity of the flooding. The construction of roads and buildings has increased the
amount of concrete being used. Concrete allows for no absorption; therefore, any rain
that falls instantly becomes runoff. Thus, the Chinese riverside cities are especially
susceptible to flooding. Excessive logging has caused serious erosion. Prior to the
deforestation, the roots of trees absorbed much of the rainwater and stored it. The bare
hillsides and plains are able to absorb only a small amount of water; the rest becomes
runoff. Chinese officials have acknowledged that the heavy tree cutting is responsible
for the severity of the 1998 floods; the Chinese government is currently working with
United Nations to stop the erosion and to replant the natural vegetation.
The death toll due to the flooding was kept to a minimal in comparison to other
years of similar water rise because of the continuous efforts from billions of peasants and
soldiers to repair and fortify dikes. However, three thousand people were still killed
from the floods; this provides evidence that dikes are not enough to control the seasonal
flooding in China. A combination of flood control methods must be exercised in order
offer full protection against rising waters. The rivers most susceptible to flooding should
be dredged; this concept seemed to work for Emperor Yu four thousand years ago.
The silt dredged from the bottom of the rivers should be used to create fertile farmlands
in impotent regions. In addition to dredging, all the dikes along rivers in especially flood
prone areas should be rebuilt during the fall and winter months when the water is low.
They should be constructed of stones that fit snuggly together; stones are not as
vulnerable to erosion as dirt, and they will not rot like tree branches or plant fibers.
Furthermore, the rivers should be widened; this would decrease the velocity of the
waters. Thus, there would be less pressure on the dikes for a given volume of water.
Trees and other vegetation should be replanted in the lands surrounding the upper
reaches of major rivers and alongside rivers in areas apt to flooding to decrease the
amount of erosion and increase water absorption. Dams should also be constructed to
bolster the other flood control techniques; however, the dams should not be placed on
the main stream but on the tributaries. In this way, it would be possible to control the
volume of water entering the main stream; thus, the water level along the whole river
could also be controlled. In case the waters do rise above the allocated danger marks
in flood prone areas, overflow canals should be dug. These canals should lead to
shallow manmade basins located in unproductive lands. In this way, water from the
reservoirs could be provided to barren lands through irrigation methods. Over time, the
basins would gradually fill with the silt deposited from floods. The remaining water
would evaporate during the drier seasons, leaving behind a rich plot of land available for
cultivation. However, when the reservoir is filled with silt, new canals leading to new
basins in other areas must be built. As an added precaution, hills constructed on a
foundation of stones or concrete should be strategically placed in areas of high
populations in flood prone areas to serve as places of refugee in case the surrounding
land becomes inundated despite the flood control efforts.
Flooding of the Chinese rivers have devastated China even before there were
written records to tell of the damage and trauma they caused. Hopefully, by employing
the latest flood-control technology and by constantly updating old methods, future floods
will not be as lethal or as frequent as the ones that desecrated the Chinese landscape in
1998.