圖書典藏及影音數位平台

為能審慎評估全球氣候變遷對水利事業可能造成的衝擊，及謀劃相關因應策略，在總體考量我國國情、體制、資源、研發與實務工作能力及水利部門應有作為，水利署於98年度執行「氣候第1階段管理計畫」，並規劃4年(99~102年)「氣候變遷對水環境之衝擊與調適研究計畫」科技研究發展專案計畫。 本項研究計畫為該整體研究計畫中之一環，目的係為整合水文環境變化、衝擊評估、脆弱度及風險評估等工作，並配合河道土砂運沖淤導致河相變遷模擬試驗，進行因應氣候變遷所造成的極端氣候中部土砂災害處理對策示範研究。本計畫擬建立濁水溪流域整體防洪、土砂產生、處理對策等相關評估模式，整合土砂災害對坡地、河道、海岸的影響，以建立極端事件下濁水溪流域現階段土砂災害處理對策，並檢討現有的土砂災害預警系統，擬定在發生極端降雨事件時，濁水溪流域水土災害疏散避難與救災對策。

Climate change will bring huge impacts to nations all over the world. Those impacts include the followings: change in biosphere, long-duration drought, large floods trigger by extreme torrential rain, spatial change in homelands, and food scarcity. The extreme weather induced by climate change is the most direct factor influencing the floods, e.g. the extreme rainfall increases discharge and inundation area, sea level and estuary water level raising induce overbank floods, and land-use abuse and land-slides trigger high concentration of sediment discharge and river bed aggradations. This project is focused on the Jhuoshuei River basin in middle of Taiwan. The project aims on the settings of hydrological scenarios due to climate change, evaluation of hydraulic structures (e.g. levees), establishing the sediment yield model of the river, sediment transport simulation are due to climate change, evaluation the impacts of sediment brought by extreme rainfall, vulnerability and risk analysis, and adaption strategy and practices for improving the capacity of the hydraulic structures of Jhuoshuei River for adapting to climate change. To evaluate the implication of climate change on sediment disasters, we developed three rainfall-triggering models, including landslide susceptibility model, landslide volume estimation model, and soil erosion model, and applied these models in the Jhuoshuei River basin. First, we used the logistic regression to develop the landslide susceptibility model and the successful rates are 75.0% validation. Second, we developed the volume-area relation, VL=0.099×AL1.356, to estimate total volume of landslide triggered by 10 rainfall events and correlated the relation between landslide volume and cumulative rainfall. Third, we used USLE to develop soil erosion model and validated with the measurement of erosion pins and cesium-137, a radioactive isotope. The estimated erosion rate are well corresponding to measures in forest and grass lands. Furthermore, the simulated results of scenario of climate change with rainfall of extreme climate duration shows that the soil erosion is 30,144×106 m3 , in A1B scenario, is 30,939×106 m3. The results of river routing from one-dimensional numerical flow model are good enough according to the calibration of Typhoon Sinlaku and validation of Typhoon Morakot. In addition, the results of river routing from two-dimensional numerical flow model are demonstrated in figures 8-15 and 8-16 based on the typhoon events in 2011 and 2012. Taking climate change scenario into the consideration, most parts of transects in the river are safe from the simulations of Typhoon Morakot, which return period equals to 200 years, and scenario A1B. The downstream near Zhuang-Yu bridge and conflux of various tributary have higher risks during typhoon events.