China has made remarkable achievements in flood control and disaster reduction. In order to minimize the loss of flood disaster, the party and the government formulated the "safety first, giving priority to prevention, to keep to the concept of all-time preparedness, emergency rescue and flood prevention work" policy, to implement the chief executive responsibility system as the core of the responsibility system of flood control.Over the past 60 years from the founding of the People's Republic of China, the direct economic benefits of flood control and disaster reduction totaled 3.93 trillion yuan, reducing the 1.60 million hectares of flooded land , And the average annual reduction of grain loss was 10.29 million tons. Before the founding of new China, the Yellow River has been 63 consecutive years of autumn and autumn flood did not happen burst.
Engineering flood control measures, in terms of its nature, can be summarized as interception, impoundment, shunt, excretion of four:
(1) interception
Interception also known as land treatment measures. Applicable to smaller watersheds, through the watershed in the soil and water conservation work, so that the land during the small rainstorm can absorb part of the precipitation or intercept part of the runoff, delay the collection time, This is the construction of silt dam, valley square, weir pond and so on. The use of these measures, such as farmland rotation system, repair terraces, afforestation, etc .; Alone is reducing effective in reducing the floods of the floods, but if it is matched or complemented by other flood control measures, it will help to reduce floods.
(2) impoundment
It is an important part of the current river basin flood control system to build dams, stop floods, reduce floods and reduce the flood burden in the upper reaching of the protected area. Reservoirs are dedicated to flood control, there will flood control as one The flood storage and detention of two. Reservoir flood storage, on the one hand can reduce the downstream peak flow, eliminating the threat of floods; the other hand, flood storage, increase the Level of comprehensive utilization of water resources, play a dual role in the eradication of interests.
(3) shunt
In the appropriate location of the river, the construction of floodgates, floods and other engineering facilities, will exceed the peak discharge of the river flow, sub-pre-opened sub-flood storage area, after the savings, and then planned, controlled to Vent, as the general called flood storage project. Second, the use of points (minus) flow canal, in the main river over a certain water level, the subtraction of part of the water, through the artificial river can be directly discharged into The lake, ocean or other rivers, can also bypass the protection zone into the river Of the lower reaching of the river, this is known as the flood diversion project. In addition, there are temporary Paokou people embankment, production embankment, can play a role in the suspension of the peak. Sub-flooding projects are usually used in highly developed cities or industrial areas upstream, because these places can neither broaden the river, nor a lot of land to build embankment, or have be En built dike, flood wall should not be increased.
⑷ excretion
Excretion is to make full use of the river's own ability to vent, so that the safety of the flood discharge. According to its engineering category can be divided into two species of river regulation and construction embankment.
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