| Summary: | 碩士 === 國立彰化師範大學 === 地理學系 === 106 === This study tested the capability of Flow-R model in simulating debris flow in the Xinfa Village, Kaohsiung City in Taiwan by comparing the simulated affected area with that mapped from orthoimages. Flow-R is a spatially distributed, empirical model and was developed for regional susceptibility assessments based on digital elevation models. It can be used to predict the affected area of the debris flow, with advantages of rapidity and low data requirements. This study firstly mapped the landslides area in the study area as the source area of the debris flow and tested the sensitivity of model parameters of flow algorithm to find out the most suitable parameters setting. The second step is to set up a set of topographic index parameters to automatically generate potential landslide areas as the source area of debris flow simulation. The results show that using the optimal parameter setting and mapped landslides as source area can obtain reasonable simulated result with an accuracy of 67.50%. Using 1.5% of landslides ratio to develop the topographic index parameters, and Flow-R model can obtain a relatively lower accuracy of 53.70%. Most of the simulated affected area were matched with mapped areas, although there is an overestimation at the transport area of debris flow. This overestimation may be resulted from the flow algorithm because the multiple flow direction algorithm can effectively simulate the width of debris flow deposition area, but can overestimated the width in the transport area. Then, by comparing the affected area simulated by using Flow-R and defined by the Soil and Water Conservation Bureau (SWCB), mapped landslides as source area can obtain with an accuracy of 72.36%, accuracy of affected area defined by SWCB was 68.91%, used the topographic index parameters to simulate can obtain an accuracy of 66.67%. Although the accuracy of SWCB is better, but the area of its definition is overestimated, and the result of Flow-R are better in affected area. Overall, the results of Flow-R simulation still have a certain degree of accuracy, and the results of the simulation can provide an initial understanding of the areas that may be affected by the occurrence of debris flow hazards. Finally, using the set of optimal parameters to simulate validation Yushan Village, Nanshi Village, and Shinkai village. Result show that parameters would be set differently depending on the terrain, for channelized debris flow the parameter X should be given a lower value, and for hillslope debris flow the parameter should be higher. After the parameter adjustment, the accuracy of 60.89%, 66.44% and 72.17% can be simulated separately.
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