植生復育區位配置對旗山溪集水區山崩潛勢之影響

Vegetation Recovery on Landslide Susceptibility in the Chi-Sun Watershed

10.29417/JCSWC.201503_46(1).0006

詹勳全(Hsun-Chuan Chan)；蔡培珊(Pei-Shan Tsai)；張嘉琪(Chia-Chi Chang)；黃文政(Wen-Jeng Huang)；吳菁菁(Jing-Jing Wu)

山崩潛感 ； 羅吉斯迴歸 ； 植生復育 ； Landslide susceptibility ； logistic regression ； vegetation recovery

中華水土保持學報

46卷1期（2015 / 03 / 01）

47 - 60

繁體中文

本研究以旗山溪集水區作為研究樣區，進行崩塌因子萃取與篩選後，以高程、坡度、地形粗糙度、坡度粗糙度、常態化差異植生指標（NDVI）、濕度指數、總曲率與總雨量等因子，利用多變量統計分析法中的羅吉斯迴歸法進行山崩潛感分析，並對照莫拉克颱風實際崩塌地分布圖，發現崩塌地多位於本模式預測的集水區上游之中高、高崩塌潛勢區，顯示本研究所選用之分析模式與山崩因子對莫拉克颱風崩塌發生處之模擬結果良好；另外，藉由莫拉克颱風侵襲前後共四期衛星影像萃取樣區內NDVI值，由NDVI分布變化可發現集水區河道附近於災後經兩年多已有逐漸恢復的趨勢，惟上游區位植生復育情況仍差，可見該區難以藉由植生自然復育的方式恢復至颱風侵襲前，仍需採用人工的方式幫助該區植物生長。因此，本研究復育策略之研擬，乃規劃集水區上游河岸周圍且地形適宜植生生長之地區，透過不同環域範圍的NDVI情境，期經由模式的分析模擬，探討研究植生復育對集水區山崩潛感值變化的影響。

In this study, logistic regression, a multivariate analysis method, was used for landslide susceptibility analysis of the Chi-Sun watershed. After extracting and selecting environmental factors, elevation, slope, terrain roughness, slope roughness, normalized difference vegetation index (NDVI), wetness index, and accumulated rainfall were selected as causal factors of landslides. An inspection of the distribution of the landslides caused by Typhoon Morakot revealed that the landslides were located in medium-high and high susceptibility areas of the upstream watershed. The predicted susceptibility values show a good agreement with the observed landslides, indicating that both the model and the factors used in the model are valid and that the simulation results match the Typhoon Morakot event. In addition, past NDVI values obtained by analyzing SPOT-5 satellite images suggest favorable vegetation recovery in the watershed landslide areas, except in the upstream areas. This study focused on providing suitable recovery and planning strategies around the riparian areas of the upstream watershed. The effects of vegetation recovery on landslide susceptibility values were evaluated using the developed model. Landslide hazard areas were analyzed and mapped on the basis of vegetation recovery for various buffer ranges.