都市洪災脆弱度因子與都市規劃防範策略之探討

氣候變遷使得極端氣候現象機率大增。特別是極端的高降雨量，因台灣人口密集與都市化程度高等因素，遭受洪災的風險將大幅提升。都市洪災脆弱度因子甚多，且因子之間更存在「影響」與「被影響」之情形，故本研究透過文獻回顧與專家座談初擬都市洪災脆弱度因子，包含「淹水潛勢」、「水災保全人數」、「土地使用強度」、「透水面積」、「人口密度」、「老幼人口」、「身心障礙人口」、「低收入戶」、「平均每戶經常性支出」等九項，進而透過決策實驗室分析法（Decision Making Trial and Evaluation Laboratory: DEMATEL）之專家問卷，藉以衡量各個因子之間影響程度強弱及影響方向。結果顯示，「人口密度」與「土地使用強度」以及「淹水潛勢」，三者為影響其它因子的影響力較強。因此，若能針對此三項因子進行檢討，其他受影響因子也可隨之有所改善。本研究亦分別提出都市規劃中可運用之都市洪災防範策略。

關鍵字

洪災脆弱度；決策實驗室分析法；都市規劃

並列摘要

Climate change is increasing the intensity of extreme weather events. Heavy rainfall is raising the risk of flood losses and damage, especially for a country with many high density and urbanization areas like Taiwan. Previous studies suggest lots of flood vulnerability factors; however, these factors are not self-independent but have correlations. Nine flood vulnerability factors are drafted first through literature review and experts' workshops, including flooding potential, number of flood evacuees, land use density, area of permeable pavement, population density, number of elders and children, number of disabled, number of low income people, and the average household expenditure. This study then applied the Decision Making Trial and Evaluation Laboratory (DEMATEL) method to analyze the answers from experts' questionnaires. The results indicate that ＂flood potential＂, ＂land use intensity＂ and ＂population density＂ are the three key factors that influence other factors. This study also provides a flooding mitigation planning strategy in urban areas according to the three key vulnerability factors.