Cause:
1.The crustal plate slips and drifts, which leads to the infiltration, loss and transfer of surface water and the loss of surface water.
2. Soil erosion, tree planting is destroyed.
3. Caused by flood season in astronomical tide.
4. Lack of water conservancy projects or fragile water conservancy infrastructure, no water conservation.
5. Not conforming to the laws of flood and drought, achieving water conservation during flood, taking water and transferring water during drought, following the laws of nature, and promoting the dynamic balance of water resources.
6. Others
Extended data:
Drought soil moisture is insufficient, which can not meet the needs of crop and pasture growth, resulting in a greater disaster of production reduction or extinction. Drought is a universal natural disaster, which not only affects agriculture, but also seriously affects industrial production, urban water supply and ecological environment.
In China, the normal growth of crops is usually affected by lack of water during the growing period, which is called drought, and the reduction of production by more than 30% due to drought is called disaster. Drought-prone areas are called drought-prone areas.
In these areas, the annual rainfall is scarce and the evaporation is large. Agriculture mainly depends on snow melting in mountainous areas or water coming from upstream areas. If the snow melting amount or water coming is reduced, it will cause drought.
Semi-arid areas in the world account for about 30% of the global land area, including some areas in northern Africa, southern Europe and southwest Asia; Central North America and northern China. The rainfall in these areas is less and unevenly distributed, so it is easy to cause seasonal drought, or perennial drought or even continuous drought.
Disaster is a general term for things that can have a destructive impact on human beings and the environment on which human beings depend. Disaster does not mean degree, but usually refers to part, which can expand and develop and evolve into disaster.
For example, the phenomenon of locust pests is widespread in the biological world. When locusts multiply in large numbers, spread in large areas and destroy crops to cause famine, they become locust plagues. The widespread spread and prevalence of infectious diseases and computer viruses can lead to disasters. All natural and social events that do harm to the natural ecological environment, the material and spiritual civilization construction of human society, especially people's lives and property.
References:
Baidu encyclopedia-drought and flood