近年來隨著氣候變遷，短延時強降雨加上高累積雨量的極端降雨事件(如莫拉克颱風等)，導致山區聚落的安全性面臨嚴重的威脅。本研究以高屏溪流域中60個鄰近河道的山區聚落，分析莫拉克颱風前後其河道寬度(Bw)、聚落與河道之距離(W)及聚落與河道之高差(H)等參數之變化，並建立兩個無因次參數(H/W與Bw/W)，接著利用判別分析法獲得聚落安全性評估關係式("H/W=-0.0377(Bw/W)+4.37")，建立山區聚落安全性之評估方法。分析結果得知，當Bw越寬，W越短，聚落越危險，而H越大則越安全。文中並以台東縣鄰近河道33個聚落驗證本關係式之適用性，整體準確率達97%。本研究所提出之方法可提供相關單位作為山區聚落災害風險評估及防災對策之參考依據。

Due to climate change in recent years,the frequency of extreme rainfall events (such as Typhoon Morakot, etc.) has increased. The rainfall patterns have changed to short-duration intense rainfall and high cumulative rainfall. The safety of mountain settlements is also facing serious threats. In this study, 60 mountainous settlements nearby the river channels in the Gaoping River watershed were used as research samples. The satellite images before and after Typhoon Morakot were used to analyze the width of the river (Bw), the distance between the settlement and the river (W) and the height difference between the settlement and the river (H) and then two dimensionless parameters (H/W and Bw/W) were established. Using discriminant analysis to obtain the assessment equation (H/W=-0.0377(Bw/W) +4.37) of settlement security, and finally the assessment method of settlement security in mountainous area was establish. The analysis results show that the settlements with the wider Bw and the shorter W are the more dangerous. On the contrary, the settlements with the larger H are the more safety. The 33 settlements in Taitung County are used to verify the applicability of the equation proposed in this paper. The overall accuracy rate is 97%. The method proposed in this study can be provided to relevant units as a reference for disaster risk assessment of mountainous settlements and disaster prevention countermeasures.