The Response Analysis Of Extreme Rainfall Events On Watershed Flood Hydrograph

In recent years, extreme precipitation events occur frequently, it has already begun related to people’s daily life and the harmonious development of society, and it has gradually become the hot issue of the academic research. At the same time, the problem of hydrology and water resources caused by extreme precipitation especially the impact of extreme precipitation in the flooding process is increasingly concerned by hydrologists. Now the study on the variation of extreme precipitation in time and space is more extensive, but research on the impacts of extreme precipitation on the watershed flood processes and human activities is still in the preliminary exploratory stage.The improving of the frequency of extreme precipitation events, the exacerbating adverse effects on human life, as well as the people improved understanding of extreme precipitation events in continuous improvement, which make the rapid development of study on extreme precipitation events and promot the study of extreme precipitation events on the process of watershed flood becoming the mission of the era of hydrologists. In this background, combined with Natural Science Foundation of China (The Sensitivity Research on the Hydrologic Processes to Extreme Weather Events NO.:51079131), this atudy carries out a preliminary research.Firstly, we needed to collect and organized the definition of extreme rainfall events and extreme flood events in theory, and determined the screening indicators of extreme precipitation events on that basis, and filtered out the extreme precipitation events. Secondly, precipitation events and flooding events were graded. And the statistical theory and methods were used to analyze the probability distribution of extreme precipitation events. Finally, we studied that the flood events were in response to extreme precipitation events, and we used a weather generator to predict the future extreme precipitation events on basis of excess storage-excess infiltration, forecasted and analyzed that the hydrological process was in response to the extreme precipitation events.In the study, we selected the Luanchuan Station of Yihe watershed, which is control of340km2. Then we selected1975-1998hours’data that the15-year flood season rainfall, evaporation and runoff folder as basic data to screen extreme precipitation events of luanchuan station. The simplex method, genetic algorithm and the LawSemb Rick optimal method are combined to calibrate and test the model. On the basis of the analysis of the Luanchuan control watershed extreme precipitation events and flooding characteristics, we classified the precipitation events and floods. The weather generator is used to forecast the future extreme precipitation events. Finally, we analyzed the response process of the description of indicators of the flood events of extreme precipitation events, studied on the prediction and simulation of extreme precipitation events, as well as, simulated of possible future river basin flood process.