南臺灣水庫集水區複合型土砂災害特性變遷趨勢分析

Analysis on the Characteristic Change Transition of Compound Disasters Occurred at Reservoir Watershed in Southern Taiwan

蔡光榮(K.J. Tsai) ； 李明熹(M.H. Lee) ； 陳怡睿(Y.R. Chen)

《鑛冶：中國鑛冶工程學會會刊》 64卷1期 (2020/03) Pp. 7-22

https://doi.org/10.30069/MM.202003_64(1).01

摘要

莫拉克（Morakot）颱風於2009年8月侵襲台灣帶來驚人雨量，嘉義縣、高雄縣（現已併入高雄市）及屏東縣等轄內山區累積連續三天最大降雨量高達2,900公厘以上，幾乎佔台灣全年平均降雨量之85%，因此造成嚴重山崩、土石流等複合型土砂災害。依據水土保持局之衛星影像判釋分析顯示，莫拉克重災區高屏溪流域即有多達10,904處崩塌與多處堰塞湖形成，總崩塌面積高達18,113公頃。有鑑於此，配合立法院於2010年通過水利署研提之曾南烏特別條例，期能以GPS／GIS／RS科技整合技術，應用於曾文、南化、烏山頭等三水庫集水區內坡地複合型土砂災害區調查和受災區相關災情資訊之蒐集分析，俾期能掌握曾南烏三水庫集水區內相關土砂災害致災因素之交互影響、大規模土砂運移機制與崩塌趨勢之時間序列分析研判、致災區域範圍與災前災後土砂災害特性變異分析，並應用高解析度衛星影像判釋分析技術於河道輸砂特性分析後，完成曾南烏三水庫集水區之土砂災害特性變遷調查分析，同時蒐集至少近10年來之重要颱風暴雨所衍生之極端降雨事件，據以作為探討在極端氣候變遷下曾南烏水庫集水區土砂災害發生機制及大規模坡地崩塌後之土砂災害運移行為等綜合性調查分析，最後提出曾南烏三水庫集水區之經營治理方案與坡地保育利用策略，以期未來可作為曾南烏三水庫集水區永續經營管理之參考依據。

關鍵字

極端降雨 ； 複合型土砂災害 ； 坡地防災 ； 集水區經營

並列摘要

Extremely rainfall events with the accumulated rainfall amount more than 2,900mm within continuous 3 days were brought by Morakot typhoon in August,2009. This project mainly focuses on applying field investigations integrated with GPS/GIS/RS technique to analyze and investigate the characteristics, and movement of sediment compound disasters. According to the satellite image analysis project was conducted by Soil and Water Conservation Bureau after Morakot event indicated that more than 10,904 sites of landslide with total sliding area of 18,113ha were found by this project. Characteristics and mechanism of debris flow, landslide and large scale soil mass movement were collected on the basis of sediment compound disasters happened on slope land within Zengwen, Nanhua and Wusanto Reservoir Watershed located at the southwestern Taiwan. Characteristic variation of all sediment related disasters are analyzed and investigated to rule out their interaction of the factors concerned above and identify the extent of large scale compound disasters induced by extreme rainfall in southern Taiwan. In order to decrease the risk of sediment compound disasters, the strategy of land conservation, landslide control treatment, hazard mitigation system and sediment related disaster prevention projects should be executed as soon as possible. Meanwhile, consideration on the mechanism and behavior of large scale compounded disasters induced by heavy rainfall become an important issue which was seriously concerned by the Taiwan government. The mechanism of debris flow, large scale landslide and soil & water conseration under the impact condition of extreme rainfall caused by climate change during the past 10 years would be recognized as a critical issue by this research. Hopefully, all results can be used as references for the compound disaster prevention and hazard mitigation systems operated by the Zengwen, Nanhua & Wusanto reservoir watershed agencies in southern Taiwan.

並列關鍵字

Extreme rainfall ； Compound Disasters ； Disasters Prevention on Slopeland ； Watershed Management