| Summary: | 碩士 === 國立成功大學 === 水利及海洋工程學系碩博士班 === 94 === The debris-flow often comes up in the mountain region of Taiwan after the 921 earthquake, and it is found that the rainfall intensity which were estimated in the debris-flow site obviously differ from the observation befor the earthquake. In recent years, the precipitations which are caused by typhoons constantly exceed the 100-year rainfall return period. In this study, the extreme rainfall intensity data (~2004) are collated to analyze its space and temporal characteristics in Taiwan. The purpose of this thesis is to discuss the rainfall intensity formulas which are generally used in Taiwan.
The precipitations are surveyed from 144 recording stations of Water Resources Agency and Taiwan Power Company, and different characteristics in temporal and space scales are indicated here. The rainfall intensity plotted in double log chart shows different characteristics in the long-duration rainfall scale and short-duration rainfall scale. The Horner IDF equations and the dimensionless IDF formulas, which are divided by 90 minutes rainfall duration, are calculated respectively in this study and the modified IDF equations reveal that they can increase the accuracy of the designed rainfall intensity.
Regional IDF formulas of short duration rainfall in Taiwan are further developed for using in ungauged area. Several tools including Principal Component Analysis, Cluster Analysis, and Geographic Information System are used here to decide hydraulic homogeneous regions. The Taiwan area is divided into 7 hydraulic homogeneous regions and the regional IDF equations of each region are also established. Finally, a geographic inquiring system is developed here to provide users inquire about all kinds of parameters of IDF formulas in this study.
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