Flood disasters and types in Kaifeng Area in Qing Dynasty

Based on collecting,reorganizing and analyzing the history materials about the Kaifeng area during the Qing Dynasty,we put emphasis on the rank,the timeframe and the details of the flood disasters.The result indicated that the Kaifeng area has altogether suffered 78 times from flood disasters,with an average of every 3.4 years from 1644(first year of Shunzhi) to 1911(last year of Xuantong).The Kaifeng area had 21 mild flood disasters,which was accounted for 26.9% of the whole disasters,and had suffered moderate Flood disasters 46 times,which took up for 59.0%,severe flood disasters occurred 6 times,which made up to 7.7% of the total number of flood disasters,and the serious flood disasters occurred 5 times,which was accounted for 6.4% of the total number.Meanwhile,we can divide the flood disasters into 3 phases.In the first phase,the flood disasters were extremely remarkable from 1644 to 1780.Their frequency reduced gradually during the rest of two phases happening from 1781 to 1911.According to the variations and frequency of the flood disasters,it shows an obvious fluctuation in the trend of the flood disasters fall-down in Kaifeng area from the early stage to the late stage of the Qing Dynasty.Lankao's flood occurred most frequently,followed by Kaifeng city.Floods in the region can be divided into the type of decision-river,the river overflow and type of precipitation.The main reason is because of the significant increase of the rainfall,the uneven distribution of the precipitation and the local rivers' easy dyke breaching.