The harm of flood

1, economic losses caused by environmental damage

Floods flooded farmland, houses and depressions, and people in disaster areas moved on a large scale; Various biological communities have also changed their community structures and habitats due to floods, thus breaking the original ecological balance. Some wild rats were drowned, some migrated to highlands and villages, and the proportion structure of wild rats and domestic rats changed.

Floods flooded the toilets and sewage pools in the village, and a large number of plants and animal carcasses rotted, leading to the breeding of mosquitoes and flies and the gathering of various pests.

2. Water pollution

Flood disaster has damaged water supply facilities and sewage discharge conditions to varying degrees. For example, toilets, garbage dumps and livestock sheds are flooded, which will cause water pollution of well water and tap water. A large number of floating objects and animal carcasses remain on the water surface, and after exposure to high temperature and sunlight, they are corrupt and smelly.

The flood also washed a lot of sediment into the water from underground, which made the sensory properties of the water body worse and turbid and suspended. In some developed urban and rural areas, industrial wastewater, waste residue, pesticides and other chemicals are not treated and disposed in time, which may lead to chemical pollution in the local water environment after being flooded, or warehouses storing toxic chemicals in some areas are flooded, resulting in large-scale chemical pollution due to chemical leakage.

3. Food pollution

During the flood disaster, food pollution has a wide range of ways and sources, which has a serious impact on all aspects of food production and operation, often leading to a wide range of food poisoning incidents and outbreaks of food-borne diseases.

Extended data

Floods are often distributed in places with dense population, high degree of agricultural reclamation, concentrated rivers and lakes and abundant rainfall, such as the warm temperate zone and subtropical zone in the northern hemisphere. China and Bengal are the countries with the most frequent floods in the world, and the floods in the United States, Japan, India and Europe are also very serious.

China, with its vast territory, complex terrain and remarkable monsoon climate, is one of the countries with frequent floods and wide influence. About 35% of cultivated land, 40% of population and 70% of industrial and agricultural production in China are often threatened by river floods, and the property losses caused by flood disasters rank first among all kinds of disasters.

According to historical statistics, during the period of 2 155 years from 206 BC to 2 1949 BC, there were 1092 major floods in China, with an average of every two years.

From the mechanism of flood disaster, flood disaster has obvious seasonality, regionality and repeatability. Most countries in the world are prone to floods in the second half of the year, while the floods in China mainly occur from April to September. For example, almost all the floods in the middle and lower reaches of the Yangtze River in China occur in summer. Flood disaster is related to the temporal and spatial distribution of precipitation and topography.

The areas with serious flood disasters in the world are mostly on both sides of rivers and coastal areas. For China, floods are generally more in the east and less in the west; There are many coastal areas and few inland areas; There are many plains and few plateau mountains.

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