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基隆河整體治理計畫(前期計畫)已於民國95年底完成所有防洪相關計畫，已完成相同於大台北防洪計畫重現期距200年洪峰流量並達防範納莉颱洪之保護程度，並經本所於民國98年完成「基隆河整體治理計畫後續追蹤及成效評估(3/3)」研究，前期計畫已達成原定之目標與效益。而行政院於民國101年4月26日院臺經字第1010022776號函中提示照經建會意見辦理，經由經建會審議「基隆河整體治理計畫後續追蹤及成效評估」綜提意見，由於基隆河整體治理計畫（前期計畫）完成後尚未遭逢類似納莉颱風強度之重大颱洪事件，相關工程措施等成果仍需實際颱洪事件進行檢驗，故需持續進行監測、分析及檢討，視需要進行相關方案之研究，爰持續辦理本計畫案。

The protection standard of the Keelung River Improvement Plan is to withstand a flood with 200yr recurrence frequency plus 1.5m freeboard. At the same time under Typhoon Nari event no overtopping of the river bank shall be allowed. Results of evaluation in this study revealed that after the improvement, all river reaches have met the protection standards. The exceptions are Sections 1 to 9 located at Kuangtu and Sertzdou in Taipei City.In this study, design discharge and precipitation data of Typhoon Nari were both used to analyze and to determine possible weak locations. Results indicated that under Typhoon Nari with the exception of Section 1 to 9 indicated above, no overtopping of river bank occurred. Local flooding along some tributary and small region in metropolitan areas had occurred. The total flooded area is 2,185 hectares. Among them, 1,856 hectares are in Kuangtu and Sertzdou. When using design discharge, similar results were obtained. The total inundation area is 2,349 hectares, and the area in Kuangtu and Sertzdou is 1,856 heaters.In order to evaluate the impact of land development along Keelung River on the risk of Keelung River flooding, different land development scenarios along Keelung River were considered. Results revealed that with land development, peak flood discharge and flood water level will increase. A 20% land development would cause a 13.62% increase in peak discharge, and at the same time, the flood water level would increase 0.5m. The increase in flood discharge will raise the risk of flooding and adversely affect safety and property of inhabitants along the river. Although the improvement in Keelung River has attended the intended goal, due to limited river width in the middle and downstream reaches, the river exists no additional margin on flood protection. It is thus suggested that strict review of future development be enforced, in order to ensure that urbanization will not affect the flood protection of Keelung River and the benefit of improvement will remain.From the above, it can be stated that the Phase I Keelung River Integrated Improvement Plan has achieved a level identical to the Greater Taipei Flood Protection Plan of 200yr recurrence frequency. At the same time it can also provide protection similar to Typhoon Nari event. Therefore, it will not be necessary to execute the Phase II works.Next year, works will carry on studies related to risks due to extreme precipitation events.