Vietnam’s 1971 Red River Delta Flood

Vietnam is located in Southeast Asia. It experiences a monsoonal climate season in the north. The season is always hot and rainy and runs from May to September. The capital city of Vietnam is Hanoi and it’s located in the Red River Delta of North Vietnam. The river has three major tributaries, namely, Thao, Lo and Da. Flooding occurs from June to October in Red River Delta, although serious flooding occurs in August when water levels are between 13-20-feet high above the ground.

Vietnam’s capital is protected from flooding by the dikes, which were built 1000 years ago. The dikes were regularly maintained to ensure they remained in good condition. Reservoirs were also built upstream in order to establish flood retention and diversion to help prevent the capital from flooding. However, the 1971 Red River Delta flood occurred at a time when Vietnam War was taking place, and the country was under US military action. Although the flood was overshadowed by the military action in the country, it was one of the worst natural disasters in the history of Vietnam. The floods affected the North Vietnam community and killed at least 100,000 people. Heavy rains likely caused the dikes to overload resulting in flooding.

The Chinese Floods of 1931

China is one of the oldest civilizations built near rivers. This was mainly because the rivers provided food (especially fish), fresh drinking water, hiding places during war attacks and water used for farm irrigation. Flooding was common in many of China’s oldest cities, and this has been happening throughout the Chinese history. However, there came a year when the floods were a wonder. That year was 1931. China’s three biggest rivers, the Yangtze, Huai and Yellow, all flooded that year. This was one of the worst floods ever recorded in history, since it killed between 1 to 4 million people in the country.

Causes

People have lived along the Yangtze, Yellow and Huai rivers for many centuries. Several reasons led to the flooding of these rivers. Starting with the weather, the long drought that occurred from 1928-1930 greatly affected China. The lack of rain during that period caused soils to dry up and made the rivers shallower. Winter then followed in 1930, which saw big snowstorms hit the country. It was then followed by extremely heavy rains in that filled the the country’s three rivers, during the spring. These rains caused the remaining snow to melt and the water volume increased in the rivers. To top it all, the Pacific Ocean currents occurred in the same year, causing 2 strong cyclones to hit China. In July 1931, China was again hit by another series of cyclones, and this month was unprecedentedly, since a total of 7 catastrophic cyclones were experienced a span of one month.

The radical changes in weather partially contributed to the flooding, but before the floods, modern farming techniques had been embraced in China so as to increase agricultural production. There was political instability in the country, thanks to wars and rebellions. This hindered the process of monitoring the rivers since the government programs were responsible for this task. As a result, the land close to the rivers was overused. Forests and wetlands were destroyed. The dams and dikes that were supposed to control the water in the rivers were wrongly built. All these caused the raging waters to break dams and river banks, leading to flooding.

Aftermath

When the three rivers flooded, 145,000 people died, according to Chinese sources. Western sources, on the other hand, recorded the death toll to be between 3.7- 4 million. The hazardous floods caused people to die due to waterborne diseases like typhus and cholera. Many others died due to starvation. On August 19, at Hankou town in Wuhan, the water level exceeded 16 meters. This was the climax of the floods, and 200,000 people drowned at night. This occurred near lake Gaoyou when water rushed through the Grand Canal and washed away dikes.

The 1975 Banqiao Dam Failure

In early August 1975, a Pacific hurricane passed on the coast of South China through Fujian Province, all the way to the north of Henan province. The warm, humid air of the typhoon met the cooler air of the north, causing a series of storms. This was due to the change in weather patterns. Three sets of storms that ensued dropped a meter of water in just three days. On the August 5, the first storm dropped 0.448 meters; this was 40% greater than the previous record. The second storm occurred on August 6, and the downpour lasted 16 hours. Later, on August 7, the third storm lasted 13 hours. China’s Shimantan and Banqiao dams were constructed along rivers and could only handle a maximum of 0.5 meters of water over three days.

The three storms caused water to fill the 2 dam reservoirs to capacity; hence, the excess runoff exceeded the rate at which water could be expelled from the dams. To begin with, the Shimantan dam reservoir on the Hong River collapsed at midnight when water rose 40 centimeters above the crest of the dam. Within five hours, its 120 million cubic meters of water was emptied.

Shortly after 1am, the Banqiao dam on the Ru River crested. Some brave people tried working in the storm to save the embankment, but their efforts were only futile. The dam’s walls crumbled, and the 600 million cubic meters of water that was behind the 6-meter high and 12-kilometer wide walls came raging like a dragon.

A total of 62 dams broke in the process. The flood diversions and dikes could not withstand the force of the water downstream; they all broke. This caused flooding of 2.5 million acres of farm land across 29 counties and municipalities. The predicaments at Huaibin city where the waters from rivers Hong and Ru met were terrible. More than 85,000 people died. This was so unfortunate because the dams collapsed without sending any warning signs. Besides that, the walls of water was travelling at about 50 kilometers per hour and telephone communication had been affected by the floods. Those who survived the flood ordeal were trapped on trees, and they went for days without food, so they had to die. Many were affected by water-borne diseases also, and they succumbed.

The 1887 Yellow River Flood

Huang He River, which is also called the Yellow River, is responsible for most hazardous floods in China. The river is three thousand miles long, running from Qinghai province in the northern mountain to the Yellow Sea, which is situated between China and Korea. Thanks to the massive property destruction and the loss of live it has caused, the river has been dubbed ‘’China’s Sorrow’’ by westerners. In 1887 alone, 900,000 people died in the floods. It did not end there as close to four million people died in the 1931 floods and almost one million died in 1938.

The Yellow river is prone to flooding due to its elevated nature. Before the 1931 floods, the 1887 floods was had emerged as the worst ever natural disaster in history. Over the centuries, dikes had been built along the river by farmers to regulate the rising waters caused by the building up of silt on the riverbed. Despite measures being taken by farmers near the river, the heavy rains overcame the dikes and caused flooding that had never been seen before.

Due to the low lying nature of plains near the city of Zhengzhou in Henan province, the waters of the Yellow River are thought to have broken the dikes in Huayankou. This made it possible for the floods to spread quickly in the entire Northern China. The floods covered an area of about 50,000 square miles and destroyed farms, homes, commercial centers and other property whose accurate value is still not known to date. A total of 2 million people were left homeless and without basic amenities. So far, the Yellow River has killed close to 4 million people due to flooding. What a curse!