氣候變遷下淡水河主河道防洪及沖淤探討

石門水庫阿姆坪防淤隧道將於2020年完工並啟用，此將改變原本河道之水流與輸砂條件；且受到氣候變遷影響，未來極端降雨強度將大幅增加。故對淡水河既有防洪設施有著極大之考驗。本研究針對淡水河及大漢溪主河道受到氣候變遷及防淤隧道雙重影響下，未來防洪能力及長期河道沖淤變化進行探討。根據氣候情境RCP 8.5之模擬結果顯示，21世紀末（2075至2099年）推估之最大洪峰量相較於基期（1979至2003年）至少增加50%以上。防洪安全部分，21世紀末下游河道有溢堤之可能。阿姆坪防淤隧道對淡水河及大漢溪主河道沖淤變化影響有限；未來河道長期變化趨勢則以下刷為主。

關鍵字

氣候變遷；防洪安全；河道沖淤；長期變遷

並列摘要

Amuping Desilting Tunnel in the Shihmen reservoir will complete and operate in 2020. These extra sediment flushing will change the flow and sediment discharge conditions in rivers. On the other hand, Climate change will lead that the intensity of extreme rainfall will increase enormously in the future. Therefore, the extreme rainfall and extra sediment flushing will challenge the existing flood control facilities. This study aims to discuss the flood control and riverbed migration for the Tahan and Tamsui rivers in the future considering the effect of climate change and the Amuping Desilting Tunnel. Our results show that under the RCP 8.5 climate change scenario, the projected peak discharge during the end of 21th century (2075 to 2099) will be at least 50% higher than that in the baseline (1979 to 2003) period. In terms of flood control, the potential of overbank will increase in the downstream area in the future. The flushing of Amuping Desilting Tunnel has limited impact on riverbed migration in the Tahan and Tamsui rivers and the trend of long-term change of riverbed in the future is dominated by degradation.

並列關鍵字

climate change ； flood contorl ； riverbed migration ； long-term change

國際替代計量

氣候變遷下淡水河主河道防洪及沖淤探討

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