經濟部水利署近年來針對西部沿海地區辦理綜合治水計畫,期望有效改善低窪地區之淹水問題。然而西部沿海地區因地形因素,廣大面積土地之高程低於大潮平均高潮位,利用工程方法改善排水達到的程度有限。因此,在工程方法之外,結合非工程方法輔助來減少災害損失的概念,已經逐漸受到重視而被廣泛討論。由於非工程方法包含範圍廣泛,且因應不同地區受災狀況與產業特性,都有可能建立不同的組合應用。基於因地制宜的推動方式,本研究擬組合多元非工程措施,建立小區域的防洪策略;同時考慮策略中所應用防洪設計標準,也需要因應區域發展規模與特性而有所差異。對於此防洪設計標準,有別於通常考慮的高程量,研究中以小區域防洪策略執行範圍來表示。特別因為執行範圍大小與各種執行措施成本規模有直接關聯性,因此研究中以歐盟洪氾管理之經濟概念,利用效益分析較佳化的方式,來決定合宜的小區域防洪策略之執行範圍。
The west coastal area of Taiwan using structural methods improvement draining water is limited ,because of the elevation of largely lands is lower than the average level.The policy for river management gradually changes into an integration approach from a traditional perspective of engineering. Considering those non-structural methods, the delineation of potential flood zones provides the primary information. Within the zones, land owner’s right might be partially limited, or additional allowance for floodproof facilities would be provided in order to reduce the possible flood damages. Since the cost of the non-structural methods are directly linked to the zones, this project proposes a framework to assess these solutions through cost-benefit analyses to obtain reasonable extents for the zones. The approach use the latest concept of WFD, comprehend water principle, ecology, landuse and economics, and using cost-benefit analysis to obtain reasonable extents of flood proofing for a community.