What are the hazards of flooding? What are the hazards of flooding?

Among the many natural disasters, floods have always been one of the natural disasters that seriously endanger the development of human society. The first page of China's written record is the glorious picture of the struggle between the working people and the flood - Dayu's water control. To this day, floods continue to be the most impactful disaster for humanity.

The floods of the Yangtze River in China have brought great losses to the middle and lower reaches of the Yangtze River and seriously damaged the healthy social and economic development. Therefore, we must conduct in-depth research on the causes, types, characteristics, and prevention and control measures of flood disasters in order to effectively prevent flood disasters.

In the 20 th century, there were three major floods in China. The first time was in 1931, when 16 provinces were affected, of which Anhui, Jiangxi, Jiangsu, Hubei, and Hunan were the most serious, followed by Shandong, Hebei, and Zhejiang. The affected area of these eight provinces reached 141.7 million mu.

According to statistics, half of the houses were washed away, nearly half of the people were lost, and many people fled with their families. The flood disaster was accompanied by other natural disasters, and the society was in turmoil at the time, so it caused a shocking situation, with 100 million people affected and 3.7 million people killed.

The two subsequent nationwide floods were after the liberation, the floods of 1954 and 1991. In 1954, the area affected by the disaster in the country reached 100 million mu, and the area affected by the disaster was 100 million mu. The floods of the Yangtze River inundated more than 4,700 acres of cultivated land, killed 10,000 people, and blocked the operation of the Beijing-Guangzhou Railway for 100 days.

The state's relief expenses for natural disasters are 100 million yuan. Other major floods include the 1958 flood at the Yellow River's Huayuankou in Zhengzhou, where the Yellow River Iron Bridge was washed away. In 1963, the Haihe River Basin suffered a rare flood in history, affecting an area of 61.45 million mu and reducing grain production by more than 6 billion catties.

In 1982, the Han River suffered another catastrophic flood, causing the old city of Ankang to be submerged and the damage was very heavy.

In 1998, a major flood swept almost half of China, and many important rivers in China, such as the Yangtze River, Nenjiang River, Songhua River and other rivers, were turbulent and the water level rose sharply. Eight million soldiers and civilians fought to the death against the floods. According to statistics, a total of 29 provinces and autonomous regions across the country suffered floods of varying degrees that year, with direct economic losses of up to 166.6 billion yuan.

However, up to now, an average of about 100 million mu of land in China has been affected by floods every year, causing disasters to 60 million mu, resulting in a reduction of tens of billions of kilograms of grain production.

Floods affect farmland and crop growth.

(1) Flood disasters cause people to suffer.

Death or injury caused by direct inundation by floods or collapse of buildings impacted by floods, as well as osmium death or death from disease caused by famine or disease. This is the most direct harm of floods to people. However, the degree of death or injury caused by different disasters and disaster resistance levels is different, especially social factors have a very important impact on the ** caused by disasters.

In the history of floods in old China, every flood disaster destroyed a large number of victims' families.

The 1938 Yellow River Decisive Attack affected 12.5 million people and killed 890,000.

2) Flood disasters lead to changes in the ecological environment, causing outbreaks and epidemics of diseases.

Floods have inundated farmland and villages, destroyed people's lives and production order, changed people's living environment, and affected the source and transmission route of infectious diseases, resulting in epidemics of infectious diseases. >> details.

3) Floods cause diseases due to the movement of people.

Due to flooding or flooding, livestock floods need to be moved in large quantities. On the one hand, the transfer of infectious agents to non-endemic areas, and on the other hand, the entry of susceptible populations into endemic areas, the migration of such populations has potential epidemic factors. Such as influenza, measles, and malaria can cause epidemics with this movement.

Some of the above frequent diseases, such as red eyes and ** disease, can also increase the chance of transmission due to dense crowds and contact.

4) Poor living environment causes morbidity.

The floods destroyed their houses, and the victims temporarily lived in simple nunnery huts, and during the autumn disaster period, they were exposed to the scorching sun during the day, which was prone to heat stroke, and the wind blew and insects bitten at night. And there are many heavy rains during the disaster period. Soak in rainwater all day long, and it is easy to catch a cold.

In particular, it increases the risk of morbidity and mortality for the elderly, frail, children and people with chronic diseases.

5) Individual immunity is reduced, mental and psychological depression is increased, and the chromogen is increased.

When the disaster is affected, food is scarce, malnutrition and immunity are reduced, so that the body's resistance to diseases is reduced, and it is easy to cause infectious diseases. Due to the anxiety, emotional restlessness, mental tension and psychological depression caused by the disaster, it affects the regulatory function of the body and can easily lead to the occurrence of diseases. Some chronic diseases of non-communicable diseases increase the seizure function and predispose to the occurrence of diseases.

Some non-communicable diseases (NCDs) and chronic diseases, such as tuberculosis, hypertension, coronary heart disease and anaemia, can increase the risk of flare-ups** or worsen them.

The biggest hazard caused by flooding is the inundation of homes and people, causing large numbers of people**. Floods can also sweep away everything in the habitat, causing significant economic losses. In addition, floods inundated farmland and destroyed crops, leading to a significant reduction in food production, resulting in famine.

The impact of flood disasters on the national economy is mainly reflected in several aspects.

1. Impact on agriculture.

Severe heavy rains and floods often cause large areas of farmland to be flooded and crops destroyed, resulting in reduced or even no crop yields. In the 51 years from 1950 to 2000, the average area of farmland affected by disasters was 9.37 million hm2, and 5.23 million hm2 were damaged.

2. Impact on transportation.

Railways are the arteries of the national economy. Many of China's main railway lines are under serious threat of flooding, and in the middle and lower reaches of the seven major rivers, there are Beijing-Guangzhou, Beijing-Shanghai, and Beijing.

9. The length of the railway threatened by floods is more than 10,000 km, and the railways in the southwest and northwest regions are often hit by flash floods and debris flows, and the railway trunk lines in these areas are high-intensity areas with frequent flash floods and debris flows.

3. Impact on cities and industries.

Cities are densely populated and are the political, economic and cultural centers of the country, with about 80% of the industrial output concentrated in cities. China's large and medium-sized cities are basically distributed along rivers and are seriously threatened by river floods, and some cities near mountains and rivers are also affected by disasters such as flash floods and mudslides.

Flood disasters not only bring huge economic losses, but also cause great damage to the living environment of human beings. This damage to the environment is mainly manifested in the following four aspects.

1. Damage to the ecological environment. Soil erosion is one of the serious ecological and environmental problems in China, and torrential rain and flash floods are the main natural factors.

2. Destruction of cultivated land. The damage to cultivated land caused by flood disasters is mainly due to the erosion of sand and the destruction of farmland. For example, in 1963, the Haihe River flooded and caused more than 130,000 hm2 of farmland to lose its cultivation conditions.

The destruction of land is even more severe when the Yellow River overflows, and each time the Yellow River overflows, a large amount of sediment covers the fertile land on both sides of the river, resulting in the destruction of large areas of farmland.

3. Damage to the river system. China's rivers are generally sandy, and the sediment is silted up due to the flooding, which is extremely serious to the function of the river, especially the flooding and diversion of the Yellow River, which has a wide range of damage to the water system and has a far-reaching impact.

4. Pollution of the water environment. The pollution of the water environment caused by flooding mainly causes the spread of germs and toxic substances, which directly endangers the health of the people.

Buildings collapsed, land was lost, landslides were landslided, lives were lost, money was lost.

Soil erosion, collapsed houses, landslides, siltation of rivers, raising of rivers.

Cities: Destroying roads, greenery, public facilities, bridges, power paralysis, and directly washing away unsturdy buildings can cause temporary damage to urban development.

Rural areas: Large-scale destruction of crops, auxiliary growth facilities, and clogging of rivers with muddy branches and mud may cause secondary flooding. Houses were washed out in large numbers, bridges, creeks turned into oceans.

Hazards of Flood Hazards:

Among all kinds of natural disasters, floods are the most common and the most harmful. Floods occur frequently, spread widely, are ferocious and destructive. Floods not only inundated houses and people, causing a large number of people**, but also swept away all the goods of the settlements, including food, and flooded the farmland, destroyed crops, and caused a drastic reduction in food production, thus causing famine.

Floods can also damage factories, communications and transportation facilities, causing damage to the Ministry of National Economy.

Flooding refers to the phenomenon of flooding and flooding low-lying areas due to heavy rain, heavy rain or continuous rainfall. Rains and floods mainly harm the growth of crops, cause crop yields to be reduced or cut off, and undermine the normal development of agricultural production and other industries.

Rainfall and waterlogging are mainly caused by heavy rain and torrential rain, so they are often closely related to flood disasters. The conceptual difference between the two is that a flood disaster refers to a disaster caused by torrential rainstorms or flooding of rivers and lakes; Rainfall refers to disasters caused by flooding and flooding. Rainfall and waterlogging mainly harm the growth of crops, resulting in reduced crop yields or no harvests; In addition to harming crops, floods also damage houses, buildings, water conservancy facilities, transportation facilities, power facilities, etc., and cause different degrees of people**.

Since floods and rainwaterlogging often occur in the same area at the same time or consecutively, it is difficult to accurately define the distinction when conducting disaster investigation, statistics, and analysis, and they are collectively referred to as flood disasters.

There are too many hazards, soil erosion, destruction of cultivated crops, reduced or no harvest. Roads, bridges and houses have been washed out, making it impassable for vehicles, affecting logistics and the economy, making it impossible to reach daily necessities, and people are displaced. Flooding has caused water quality to deteriorate, making it impossible to drink directly and susceptible to various diseases.

The first is the harm to people's lives, and the second is the heavy loss of property. There are also infectious diseases that can occur after floods.

1. Crop yields were reduced by disasters. Major floods have caused a large amount of farmland to be washed away and submerged, crop yields have been reduced or even lost, and the agricultural product processing industry and light industry have lacked raw materials or the cost of raw materials has increased, resulting in factory production reduction and shutdown, followed by unemployment of workers.

2. The interruption of transportation and communication makes the information and transportation blocked or delayed, resulting in a large number of product backlogs and deterioration, insufficient raw materials, and a decline in production capacity. In particular, the blockage of emergency relief supplies is likely to amplify existing disasters.

3. Major flood disasters have caused a decline in the living standards of the people in the disaster areas, and there is a lack of basic livelihood guarantees, resulting in a large number of victims, disrupting the normal social order and impacting all aspects of society.

4. Cause great damage to the environment on which human beings depend. For example, floods will cause soil erosion every year, a large amount of soil and its nutrients are lost, resulting in poor land, and at the same time, the sediment content in the water flow increases, resulting in the attenuation of river function, the shrinkage of lakes, and the desertification of cultivated land, and the serious consequences are incalculable.

5. The pollution of the water environment by flooding mainly includes the spread and spread of toxic and harmful substances such as germs, parasites, industrial waste residues, waste liquids, chemical fertilizers, pesticides, etc., which will seriously endanger people's lives and health. In addition, flooding will have a significant impact on shipping, transportation, tourism, aquaculture, etc.