流域之颱洪災害衝擊、脆弱度與調適之特性及關聯性分析：以莫拉克颱風高屏溪流域村（里）為例

A Watershed-Based Impacts, Vulnerability and Adaptation Analysis to Risks Posed by Typhoon: A Case Study of the Villages in Kaoping River Basin Affected by Typhoon Morakot

劉怡君(YI-CHUNG LIU)

指導教授 ： 洪鴻智

國立臺北大學/公共事務學院/不動產與城鄉環境學系/博士(2016年)

摘要

近幾年如莫拉克颱風之慘痛教訓，不但揭露傳統河川治理與個別災害管理途徑之困境，更顯明面對極端氣候事件趨勢，當代風險治理者必須從多元角度理解災害風險跨災害、跨領域、跨行政區之複合屬性，方能提出有效之跨域治理策略。基此，本研究結合傳統災害風險形成機制與氣候變遷災害衝擊理論，從整體流域之空間脈絡，建立颱洪災害風險評估模型。本研究以莫拉克颱風為例，並選取高屏溪流域為研究對象，運用多變量統計模型、空間統計模型、地理資訊系統、問卷調查等方法及工具，系統性地評估各村(里)之颱洪災害脆弱度與莫拉克颱風衝擊程度，同時探討影響民眾調適行為決策的重要因素，並分析「脆弱度－衝擊－調適」之關聯性。
研究結果顯示莫拉克颱風前高屏溪流域內各村（里）之颱洪災害脆弱度，在上中下游有明顯的空間分布與地域性群聚特徵，且導致這些地區高脆弱度的主要因素不盡相同。莫拉克颱風對高屏溪流域所帶來之衝擊亦具有空間群聚特性，高海拔地區為坡地崩塌、橋樑損壞以及農業損失之熱區，中游支流匯流處為淹水熱區，而下游河川東側近出海口地區則為房屋損毀熱區。此外，高達九成民眾於災前會採取短期自主性調適措施，但僅有四成會採取災後調適措施；其中，防災教育、災害經驗與風險認知為影響個人調適行為的重要因素，而社經條件與災害資訊則多不具影響力，甚至社會支持與社會信任可能會降低民眾自主調適意願。
研究同時發現高災害潛勢、高海拔、高度土地開發以及低調適能力等高脆弱度地區，為莫拉克颱風人員或財產損失較嚴重區域。不過傳統認為會導致災害損失的人口與社經脆弱度因子，解釋力則不佳。在影響個人調適行為的村（里）脆弱度面向上，實質環境與土地使用之敏感性具有正相關，但人口社會經濟與調適能力則具有負相關。至於莫拉克颱風之人員與財產損失，則均會提升民眾採取災後調適行為之意願。最後，根據實證分析結果提出流域上中下游之災害風險治理策略建議，以作為相關決策參據。

關鍵字

莫拉克颱風 ； 調適 ； 衝擊 ； 脆弱度 ； 高屏溪流域

並列摘要

Typhoon Morakot's devastating impacts reveal great challenges to the traditional approaches to both river basin management and disaster risk management. To cope with the increasing risks posed by extreme weather and climate events, the risk managers have to recognize the complex nature of disaster risk, which is usually multi-hazard, multi-disciplinary, and cross jurisdictional boundaries. Accordingly, effective strategies for disaster risk governance must be developed. Based on an integration of the risk-hazard model and the climate change impact model, this research proposes a novel methodology to assess the disaster risks posed by typhoons. Specifically, we use a multi-criteria assessment which includes multivariate analysis, spatial statistical analysis, geographic information systems and questionnaires. Using the Kaoping River Basin as a case study, we analyze different phases of Typhoon Morakot-induced risks. Firstly, we assess the pre-event vulnerability and the impacts of Typhoon Morakot at the local level. Next, we examine the key factors that influence residents’ decision-making for adaptation to typhoon related risks. Finally, we analyze the relationship among vulnerability, impacts and adaptation.
The research results show that there is an apparent spatial pattern in the local vulnerability among the upstream, midstream and downstream areas. Also, the significant indicators vary among different areas. There is a pronounced spatial clustering of Typhoon Morakot’s impacts. For example, the hotspots of landslide, bridge damage and agriculture loss are located in upstream regions, the flooding hotspots are concentrated in the midstream zones where the tributary joins, and the housing damage is mainly in the lower east downstream near the mouth of Kaoping River. Furthermore, up to 90% of residents adopted a short-term autonomous adaptation before a typhoon arrives. Conversely, less than 40% of residents adopted adaptive measures in the aftermath of typhoon-caused disasters. Those indicates, such as risk perception, disaster experience and public education for disaster risk reduction, are critical in determining personal adaptation. However, socioeconomic status and typhoon warning message do not certainly affect adaptation; rather social support and social trust have negative effects on autonomous adaptation.
The analysis results provide partial support for the correspondence among vulnerability, impacts and adaption. The findings demonstrate that the casualties and property losses caused by Typhoon Morakot are significantly affected by the context of local vulnerability, such as larger hazard-prone areas, higher elevation, more intense land uses and less adaptive capacity. It is noteworthy that neither demographic nor socioeconomic indicators, which are usually seen as key vulnerable factors, are strongly correlated with disaster losses. The findings also indicate that the local sensitivities related to biophysical and land use are positively correlated with personal adaptation, yet there is a significant negative association between personal adaptation and local demographic characteristics or local socioeconomic status. In addition, Typhoon Morakot’s losses are significantly positively related to personal adaptation. In conclusion, we suggest that guidance of risk governance should account for different areas of a river basin in order to enhance effectiveness of disaster risk reduction for future typhoons.

並列關鍵字

Typhoon Morakot ； Adaptation ； Impacts ； Vulnerability ； Kaoping River Basin

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