Spatial and temporal distributions of floods and droughts in Jialing river basin in the Ming and Qing dynasties

Based on the systematical collection of historical data,and quantitative statistics and analysis,this paper examines the characteristics and rules of floods and droughts of Jialing River in the Ming and Qing dynasties.Five main conclusions can be drawn as follows.(1) The disasters occurred frequently,with floods a bit more than droughts.The frequency of the former is 3.03 times per year while the latter is 2.56 times.(2) Most of the disasters occurred in May,June and July in the Chinese lunar calendar.Specifically,over half of the flood events occurred in these months,accounting for 69.5% of the total,and more than half of the drought events were observed in this period.(3) The Fujiang River basin suffered far more disasters than other areas.It witnessed 31% of flood events and 38% of drought events of Jialing River basin.(4) There are more normal and major disasters than extremely serious disasters.Extremely serious floods accounted for 10.85% of all the floods in this basin during this period,and extremely serious droughts accounted for 12.29% of the total.(5) The forest coverage is inversely proportional to the frequency of floods and droughts in this area.We believe that the results will provide reference for disaster mitigation and prevention in this basin.