Using GIS to Analyze the Eco-environmental Vulnerability of Debris Disaster Watershed Areas-An Illustration of Zhiben River and Taimali River Watersheds

• Main Authors: Kuei-Chia Chen, 陳桂嘉
• Other Authors: Chaur-Tzuhn Chen
• Format: Others
• Language: zh-TW
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/80315302757504275907

碩士 === 國立屏東科技大學 === 森林系所 === 98 === Due to the geographical location, earthquakes and typhoon frequently hit, that is easy to cause the sediment disasters in Taitung County. Among the watersheds in Taitung, the river watersheds of Zhiben and Taimali are more serious natural disaster areas, in which landslide is the most serious type of sediment disasters in those watersheds. The purpose of this study was to build an eco-environmental vulnerability for the landslide disaster watershed. First, we integrated GIS and RS techniques to build the eco-environmental data base. Second, we used the factor analysis to get the weights of landslide causing impact factors. Third, we used fuzzy set to build the membership function of the impact factors. Fourth, we used environmental vulnerability index (EVI) to assess the eco-environmental vulnerable area of watershed. Finally, we created the assessment model of vegetation recovery that was based on the natural potential environmental factors and the protected object factors. The results indicated that not only landslide occurred was base on the watershed environment at factors, the impact of human activity was also an important factor in these two watersheds. In this study, the vulnerability was divided into six levels, such as safe, light, moderate, heavy, heavier, and extreme levels. In Zhiben and Taimali river watersheds, there were more than 75% of the landslides occurred between heavier to extreme levels, indicating that the landslides were located in high-risk and high-vulnerability areas. Especially, Taimali river watershed was the gravest, and there was 41.35% of landslide belonging extreme level. The most vulnerable area was Granville village, Taitung County in the Taimali river watershed. According to the landslide vegetation recovery assessment model, the First Score (FS) was divided into four levels, including postponement, reinforcement, precedence, and immediateness. The landslides at immediateness level in Zhiben and Taimali river watersheds are 29.41% and 29.41%, respectively. Comparing with the requirement of vegetation recovery of landslide in these two watersheds, the average value of Zhiben’s FS was 0.46, and those of Taimali’s FS was 0.52. Therefore, landslide of Taimali river watershed is necessary to give the precedence action. This research can give the guideline of vegetation recovery in future.