台灣地狹人稠，河川流域與坡地在土地過度開發及台灣氣候影響下，流域水土災害發生頻率相當高，為了避免流域氣象災害對於人類造成重大的衝擊，開發前對於該地的氣象災害風險評估及預警便相當重要。以往的災害預警評估較著重短期預警，但隨著氣候變遷影響之下，逐漸重視長期評估對區域發展的重要性。 本研究藉由系統分析探討流域環境的氣象災害，並建立風險評估架構進行風險評估。將流域氣象災害從災害發生前階段、災害衝擊階段、災害發生後復原階段做各因子評估，可以有效了解區域內的氣象災害對當地是否有重大的影響。最後以小林村遷村做為案例研究，探討遷村後風險值與小林村遷回原村風險值之差異，可提供災害發生後重新選址參考。 小林村630人，有90戶仍留在甲仙區小林里，約有180戶遷至杉林區上平里及月眉里。在土石流災害風險評估之下，上平里及月眉里人口面對土石流風險為0.5598(中等風險)，若遷回原村址，小林村遷村人口面對土石流風險為0.3981(中低等風險)，減少面對的風險足足少了一個層級。回復度評估結果顯示，暴露度越高的地區，因人群聚集及發展較高，其回復度通常也較高，災後復原能力較強，因此風險評估若加入回復度指標，能提供決策者配置防救災資源之位置。 ;This research discusses meteorologic disasters in basin scale with system analysis approach. The proposed frame for basin risk assessment consists into three steps, namely disasters happened stage, disaster happening stage, and after disaster recover stage. Each stage has its own factors, and these factors can be utilized to indicate the relative status in the area of the risk assessment. The relocation of Xiaolin village is chosen as a case study. The difference between the risk assessment value before village relocation and after village relocation is discussed. There are 630 people in the original Xiaolin village. Among them, about 90 families still stay in Xiaolin village, Jiaxian Dist., and 180 families relocated to either Shangping village or Yuemei village. In risk assessment of debris flow, the risk value of Shangping village and Yuemei village is 0.5598, i.e., moderate risk. However, in the case that the relocation people in Shangping village and Yuemei village come back to Xiaolin village, the risk value is 0.3981, i.e., moderate and low risk. Incorporating resilience in the assessment shows the higher the exposure is, the higher the resilience gets. This is because the high population area always has enough resource encountering disaster. In the same time, the high population area has strong resilience ability.
