What is a flood disaster?

Flood disaster refers to the phenomenon that low-lying areas are flooded and waterlogged due to heavy rain, heavy rain or continuous rainfall. Rain and waterlogging mainly endanger the growth of crops, resulting in crop yield reduction or crop failure, and undermining the normal development of agricultural production and other industries.

Waterlogging is mainly caused by rainstorm and heavy rainstorm, so it is often closely related to flood disaster. The conceptual difference between the two is that flood disaster refers to the disaster caused by heavy rain or flooding of rivers and lakes; Rainstorm refers to waterlogging and flood disaster. Rain and waterlogging mainly endanger crop growth, leading to crop yield reduction or crop failure; Flood not only harms crops, but also damages houses, buildings, water conservancy facilities, transportation facilities and power facilities. , and caused different degrees of casualties. Because floods and rainstorms often occur in the same area at the same time or continuously, it is difficult to accurately define their differences in disaster investigation, statistics and analysis. At this time, it is collectively referred to as flood disaster.

Flood disaster distribution

Globally, floods mainly occur in areas with frequent typhoons and rainstorms. These areas mainly include: northern Bangladesh and coastal areas; Southeast coast of China; Japan and Southeast Asian countries; The Caribbean and the eastern coastal areas of the United States. In addition, inland river basins in some countries are also prone to floods.

The harm of flood disaster

Among all kinds of natural disasters, flood is the most common and harmful one. Floods occur frequently, spread widely, are fierce and extremely destructive. Floods not only flooded houses and people, causing a large number of casualties, but also swept away everything in human settlements, including food, flooded farmland, destroyed crops, and led to a sharp reduction in food production, which led to famine. Floods will also damage factories, communications and transportation facilities, thus causing damage to the Ministry of National Economy.

Since the beginning of this century, there have been nearly 40 catastrophic floods around the world, each of which has caused tens of thousands of deaths and millions of people have been displaced. In recent decades, the frequency of floods and disaster losses have increased year by year.

China has been a country with severe floods since ancient times. According to incomplete statistics, during the period from 206 BC to 2 155 BC 1949, there were 1092 floods in * *, and floods with more than 10,000 deaths occurred every 5-6 years. This situation has not fundamentally changed in modern times.

Flood disaster not only directly causes casualties and property losses, but also causes a series of other disasters such as landslides, mudslides and epidemics. Rain and Waterlogging in China

1951-1990. There are 5.9 serious floods every year in China, with an average affected area of 6.67 million hectares, including 4.7 million hectares, with 30 to 4,000 deaths and more than 2 million houses collapsed. 199 1 year, floods occurred in 25 provinces, cities and districts in China to varying degrees. The affected area of crops was 24 million hectares, with 5 133 deaths and 4.98 million houses collapsed, resulting in direct economic losses of 79.9 billion yuan.

The main waterlogging areas are distributed in Daxing 'anling-Taihang Mountain-east of Wuling Mountain, which is divided into four frequent areas by Nanling, Dabie Mountain-Qinling Mountain and Yinshan Mountain. There is little rain in the west of China, and only Sichuan is a rainy and waterlogged area.

According to historical waterlogging statistics, the most serious waterlogging areas are mainly the southeast coast, Hunan and Jiangxi provinces and Huaihe River basin, followed by the middle and lower reaches of the Yangtze River, Nanling, Wuyishan, Haihe River and Yellow River, Sichuan Basin, Liaohe River and Songhua River. The areas with the least rainfall and waterlogging in China are Northwest China, Inner Mongolia and Qinghai-Tibet Plateau, followed by Loess Plateau, Yunnan-Guizhou Plateau and Northeast China. Generally speaking, the distribution of rain and waterlogging is characterized by more in the east and less in the west; There are many coastal areas and few inland areas; There are many lakes in the plain and few mountains in the plateau; There are many slopes in the east and south of the mountain range, but few in the west and north.