| China is a country where droughts and floods occur very frequently.Exploring the mechanism of drought and flood disasters is of great significance to the prevention of disasters and disaster relief after disasters.This paper selects the Fuhe River Basin as a research area,collects data of droughts and floods from 1470 to 1949 through a large number of local records and literatures,and establishes a series of drought and flood disasters in this area.Using mathematical statistics,wavelet analysis and sliding t-test,the scientific analysis of the frequency,intensity,cycle,and abrupt changes of droughts and floods was carried out.The impact of droughts and floods on the local area and the post-disaster society were elucidated in detail.Responsive measures.The following main conclusions have been drawn:1.The data in this paper is from historical data of drought and flood disasters in10 counties in 2 districts of Fuhe River Basin.In combination with the actual situation in the Fuhe River Basin,the drought and flood disasters were divided into five grades,and then the text description was parameterized,and the drought and flood disaster grades in the Fuhe River Basin during 1470-49 were reconstructed.2.The frequency and frequency of drought and flood disasters in the Fuhe River Basin indicate that the frequency and frequency of drought and flood disasters in the Fuhe River Basin indicate that from 1470-1949,there were 289 droughts and floods in the Fuhe River Basin,including 105 droughts.An average of 2.66 years;disaster relief 184 times,once in an average of 1.52 years,the frequency of occurrence of disaster relief is greater than the drought.In the drought,there were 26 occurrences of Grade 1 drought,an average of 10.73 years;79 occurrences of Grade II drought,and an average of 3.51,Grade 2 drought occurrence frequency is higher than Grade 1drought.In the disaster relief,there were 43 occurrences of grade 5 paralysis,an average of 6.49 years;there were 141 occurrences of grade 4 paralysis,an average of1.98 years,and the frequency of grade 4 paralysis was higher than that of grade 5paralysis.To sum up,the frequency of occurrence of droughts and floods in the Fuhe River Basin from high to low is: 4 partial hemispheres,2 hemispheres,5 droughts and1 drought.According to the statistics of the century,the frequency of droughts in the16 th century was greater than that of flood disasters.In the other centuries,flood disasters were greater than droughts.From the historical point of view of statistics,the Fuhe River Basin is more disaster relief than drought.3.The intensity analysis of flood and drought disasters in the Fuhe River Basin shows that: by calculating the average drought and flood index,it was found that the drought and flood intensity in the region generally represented flood disaster greater than drought,and the drought intensity was greater than the flood disaster only in a certain time period.Seen from each dynasty,the floods and floods of the Ming Dynasty alternated.The Qing dynasty suffered severe plagues.During the period of the Republic of China,locust plagues were severe.The intensity of locust plagues was greater than drought during the entire period.4.The analysis of flood and drought cycles in the Fuhe River Basin shows that the 480-year drought and flood disaster sequence in the Fuhe River Basin was subjected to wavelet analysis,and eight cycles were obtained at the 480 and 100-year resolution scales,ranked by the number of occurrences.They appear 5 times on13-18 a,3 on 21-27 a,3 on 31-33 a,3 on 52-54 a,3 on 55 a,2 on 4-9a,1 on 90 a,260a.Appears once.Judging from the number of occurrences,the 13-18 a cycle has the largest number,indicating that the drought and flood disasters in the Fuhe River Basin have a major oscillation cycle at 13-18 a.5.The catastrophic analysis of drought and flood disasters in the Fuhe River Basin indicates that the drought and flood evolution in the Fuhe River Basin was conducted on the 480-year and 100-year sliding t-tests,respectively.This paper obtains the catastrophic changes in drought and flood disasters in the Fuhe River Basin.The order was: from 1476 to drought,1518 from dry to flood,1522 from flood to dry,1540 from dry to dry,from 1632 to dry,1658 from dry to dry,in 1716 by the transfer The drought changed from drought in 1820 to drought in 1832 and drought in1924.6.The impacts of floods and droughts in the Fuhe River Basin and their social responses indicate that the impacts of floods and droughts in the Fuhe River Basin and their social responses indicate that during the time period from 1470 to 1949,droughts and floods frequently occurred in the communities of the Fuhe River Basin.Development has caused serious adverse effects,mainly as a result of the destruction of agricultural production,resulting in a decrease in population and affecting social security and stability.In order to alleviate the impact of droughts and floods,the government and the people have taken a large number of prevention and control measures,mainly actively constructing various water conservancy facilities,vigorously carrying out warehousing construction and implementing government relief.These measures for the prevention and control of droughts and floods played an important role in rebuilding post-disaster order,reducing government pressure,restoring the normal production and living of disaster victims,and alleviating social conflicts. |
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