圖書典藏及影音數位平台

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淡水河防洪處理對策示範研究。本計畫擬建立流域整體防洪需求、土砂產生、處理對策相關評估模式，整合土砂災害對坡地、河道、海岸的影響，以建立極端事件下淡水河現階段防洪及土砂災害處理對策，並檢討現有的防洪及土砂災害預警系統，擬定在發生極端降雨事件時，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 including 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 two-year project is focused on the Tamsui River basin in northern Taiwan. The project in the first year 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, and preliminary strategy for adapting to climate change. The project in the second year aims on 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 Tamsui River for adapting to climate change. The fruitful results of this year are briefly described. The hotspots of overbank of the dike are found in 9 locations in main Tamshui River; 9 in Keelung River; and 1 in Shindan River. The weight of landslide and soil erosion due to climate (A1B scenario) is 320×?10?^4 ton and 1,253×?10?^4 ton, respectively in Tamshui River. The landslides concentrates in the Shihmen Reservior and Keelung River and the weight of landslide of the Shihmen Reservior and Keelung River are 834.45×?10?^4 ton and 257.09×?10?^4 ton, respectively. The soil erosion constrates in Keelung River, Fei-Tsui Resverior, and Shindan River. The soil ersion of Keelung River, Fei-Tsui Resverior, and Shindan River due to A1B are 81.77×?10?^4 ton、81.28×?10?^4 ton and 70.47×?10?^4 ton , respectively. The total sediment yield of the Tamshi River is 1,019.82 ×?10?^4 ton, and concentrates in Shihmen Reservior (625.24 ×?10?^4). As for Fei-Tsui Resverior, Shindan River, the sediment yield are 114.07×?10?^4 ton, 113.26×?10?^4、110.06, ×?10?^4 38.9×?10?^4, respectively. The river bed changes more in the upstream of main stream of Tamshui River the than that in the downstream of the main stream. The maximum deposition of 3 m is found in Keelung River, and 6m is found in Shindan River. As for Jingmei River and Sanxia River, the deposition or scouring is not significant. Riskmap of dike failure shown the highest risk resides in upper stream of the Tamshui River. The higher risk spots of the whole watershed can break down to: 8 in Tamshui River; 16 in Keelung River, 7 in Shindan River; 5 in Jingmei River；3 in Sanxia River. The strategy of Tamshui River due to climate change includes: build an disaster-resistant society, capacity building for the resident in flood-prone areas, and adaption to the new threats brought by climate change.