| Summary: | 碩士 === 國立中興大學 === 水土保持學系所 === 101 === Due to global climate change, the occurrence frequency of high-intensity rainfall events have increased, which causes huge amount and scale of disaster at the slope land. The surface runoff intercepted by the roads might erode the nearby slope toes and can severely affect the road safety when heavy rain hits mountain regions. To improve this phenomenon and protect prior target from slope disasters, Yizen bridge watershed of Puzih River is selected as a study site in this study for analysis of concave collapse potential, headstream collapse potential of watershed, upslope collapse potential and topographic wetness index. Meanwhile, the vulnerability potential along roads is extracted by overlaying road map and four analysis results mentioned. The topographic depressions are then extracted from DEM to determine deployed order of topographic depressions with the analysis of CN value at spots which have high vulnerability potential nearby. The results show that high potential areas are mainly located in the downstream of the watershed outlet. The security of roads will be threatened by slope failure due to inappropriate drainage. To overcome this situation, the proper topographic depressions alone roads must be extracted to lead runoff intercepted by road into detention facilities. Therefore, the impact from increasing peak discharge due to land development can be released for downstream areas. There are 14 topographic depressions and each detention amount along with high vulnerability potential spot can be obtained by order analysis. 7 of 14 topographic depressions are found lacking enough detention amounts. These topographic depressions are recommended to increase detention amounts by widening and/or deepening specific topographic depressions to enlarge their disaster prevention ability.
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