Water is the milk that feeds human beings. Without the nourishment of water, there would be no reproduction of life; A world without water will be a world of death. Because of water, the earth is full of vitality. However, due to various reasons, on the one hand, human demand for water is increasing, on the other hand, it is artificially wasted, and people pollute water resources, which makes water resources continuously exhausted. The crisis of water resources will become one of the most serious practical problems facing mankind in the 2 1 century.
Types of water crisis
For the convenience of research, water crisis can be divided into direct water crisis and indirect water crisis.
Direct water crisis refers to the direct threat or harm to water security caused by unexpected events, including natural disasters and man-made disasters. Natural disasters are also called natural crises, such as heavy rain, flash floods, droughts, typhoons, earthquakes, mudslides and other natural forces that directly undermine the stability of water supply and defense, such as floods and droughts that threaten or endanger the safety of life and property. Although this natural crisis is irresistible, it is generally foreseeable because there are natural laws to follow. Man-made disaster, also known as man-made crisis, refers to the threat or harm to water supply safety directly caused by people's subjective behavior, such as man-made water pollution and man-made water engineering damage. This man-made crisis is considered as a direct water crisis, because these man-made emergencies are directly related to water and have relatively fixed actors. For example, factories discharge pollutants into rivers and reservoirs, and fish-frying incidents around reservoirs. The water management department can foresee and take corresponding protective measures according to the previous management experience.
Indirect water crisis refers to the threat or harm to water safety indirectly caused by seemingly unrelated emergencies, mainly man-made disasters. Such as war, disease, terrorist activities, explosions, strikes, demonstrations and other political or economic emergencies. For example, the water quality problems caused by the SARS epidemic in previous years, especially the sewage discharge and treatment of hospitals that treat SARS patients at designated points. This seemingly unrelated emergency is unpredictable, random and irregular on the whole. The water management department can't judge the regularity of its occurrence according to the previous management experience.
Therefore, direct water crisis and indirect water crisis have the following main differences:
(1) From the cause of formation, direct water crisis is induced by events directly related to water, and indirect water crisis is induced by events indirectly related to water.
(2) According to the occurrence law, direct water crisis generally has rules to follow, and can be predicted according to frequency analysis or accumulated management experience; Indirect water crisis has no rules to follow, and it is extremely accidental and unpredictable.
(3) In terms of frequency and quantity, direct water crisis is frequent and large-scale; The indirect water crisis is accidental and small.