台北地區洪水災害風險分區劃設之研究

ON THE RISK ZONING OF FLOOD HAZARD IN TAIPEI AREAS

台灣地區洪水災害頻繁，所造成的損失與影響非常嚴重，目前國內防洪方法多半採取工程措施，但由於天然災害具有不確定與損失產生等「風險」特性，因此國外大多採用風險概念，以分析天然災害的發生，達到全面性災害預防，此亦凸顯出我國國土空間規劃上對於災害預防不足之處。有鑑於此，本研究將災害風險概念運用於臺北地區水災災害，根據國內外相關文獻，建構水災風險評估架構，並依照所建立的評估架構將風險分成機率與損失兩部分進行評估，災害損失部分利用專家問卷與模糊德爾菲法（Fuzzy Delphi Method），取代尚未調查完全的現況資料；水災發生機率部分，則以淹水潛勢資料與重現期關係估計之。分析結果將研究地區水災災害風險分成五個等級，並繪製水災風險分區圖。本研究經實例研究發現，研究地區大部分為水災低風險地區，其土地使用多為自然地區與農業地區，而水災災害風險非常高地區，則集中分佈於基隆河沿岸，土地使用則多為都市高密度住宅地區、都市中密度住宅地區與傳統工業區。本研究成果未來可應用於相關單位進行水災災害的國土空間防災規劃，或提供後續研究與災害保險等相關規劃運用。

This research made use of the conception of risk to evaluate flood hazards in Taipei area, and we constructed the framework of risk evaluation of flood risk. We divided risk to probability and damage cost in order to evaluate it. The damage cost of flood was made use of the analytical results of expert questionnaire and Fuzzy Delphi Method. The probability of flood was evaluated by the relationship between the inundation potential material and the return period. Finally, we analyzed the risk of flood in our study area by using GIS, divided the results into five ranks, and drew the risk maps of flood hazard. This study found that the very low flood risk areas, which are the main areas in the study area, are natural districts and agriculture districts. However, the very high flood risk areas, concentrating in the banks along Keelung river, are urban high residential districts, urban middle residential districts, and traditional industrial districts. The achievement of the research could be applied to hazard mitigations of our national territory space plans by correlative units in the future, or be used by subsequent correlative research or hazard insurance.