Preliminary Study On The Flooding And Drought During The Ming And Qing Dynasties Of China In Wujiang Drainage Basin

Wu River is a tributary of the upper reach of Yangtze River. Its origin is in Yi-Hui-Miao Autonomous County of Weining in Guizhou province. The northern origin is in Liuchong River and the southern is in Shancha River. The two rivers join in the border zone called Maoeryan of Zhijin County, Qianxi county and Qingzhen City and then runs through North Guizhou, Central Guizhou and southeast Chongqing and finally flows into the Yangtze River in Fuling District in Chongqin. With a total drainage area of89,000square km, Wu River Basin includes the central and northern part of Guizhou Province, the southeast part of Chongqing, some area of the northeast part of Yunnan Province and the southwestern Hubei Province. Located in northeast Yunnan-Guizhou Plateau, most of Wu River Basin is in karst and limestone formations and mostly is karst basin and lysogenic. This geologic structure is sensitive to floods and drought, each defined by its unique set of properties. So far there is no related achievement in research of the flood and drought disasters in Wu River Basin. Only in the research of provinces such as Guizhou and Sichuan, the flood and drought in partial Wu River Basin is mentioned. For want of systematical research on the flood and drought disasters in this area, this paper tries to do some preliminary research to find out the temporal and spatial distribution features of the flood and drought disasters in Wu River Basin from the angle of historical geography, in the hope that my research would generate more public discussion and would be helpful to preventing and reducing disasters in Wu River Basin.The research comprises four parts:Part one serves as the introduction of the whole research, including the current situation of the study of floods and drought in Wu River Basin and the formers’ achievement in research. This part defines the focal and difficult points, innovation points, the research methodology and related concepts.Part two analyzes the disaster grade of the flood and drought disasters in Wu River Basin. Combining the review of several types of ways to classify the disaster grade in the academic world with the data collected by myself, this part summarize standards to classify the disaster grade of the flood and drought disasters in Wu River Basin, and define the disaster grade of the flood and drought disasters in Wu River Basin accordingly.Part three is the temporal and spatial distribution features of the flood and drought disasters in Wu River Basin in Ming and Qing dynasty. According to analysis of related data, some basic conclusions about the characteristics of drought in Wu River Basin have been achieved.Part four explains the causes and influence of the temporal and spatial distribution in Ming and Qing dynasty from the nature, the society and collected data and summarizes the influence of the flood and drought disasters.