圖書典藏及影音數位平台

二重疏洪道自開始使用後因諸多自然演變及人為改變因素，致其而分洪及通洪能力不再滿足原設計之功能；而周邊之相關開發計畫也可能進一步降低其整體防洪功能。 縱上所述，實有必要重新檢討二重疏洪道之整體防洪能力，由於現地已存有橋梁、道路、停車場、運動設施、公園及植栽等，其影響通洪能力，應就上開研提適當之改善策略及配套措施，並進行可行性分析，最後提出改善之優先順序俾供管理單位參酌，故成立本計畫。

Since the Erchong floodway was completed and opened due to natural changes and human use, its water conveyance has no longer to the original design; and related development plans may further reduce its flood prevention function. To sum up, it is necessary to re-examine the water conveyance of the Erchong floodway. The water conveyance strategies can be divided into three aspects: “planning scope and rights and responsibilities of other agencies”, “authorization of water conservancy law” and “change of natural environment”. This research has been based on the improvement programs permitted by the water conservancy authorities. Based on the analysis of a total of 8 single cases and combining them into 6 composite cases, the analysis result is more feasible. The improvement scheme is the case1 (removal of the Sanchong and Lujhou landfill lump + dredging at the upstream reach of the inlet weir+ adjust bed elevaction 2~3m of upstream reach), and case2 (removal of the Sanchong and Lujhou landfill lump + dredging at the upstream reach of the inlet weir+ reduce the height of inlet weir+ adjust bed elevation 2~3m of upstream reach) can increase 585 cms and 610 cms, respectively; the limit improvement is case3 (removal of the Sanchong and Lujhou landfill lump + dredging at the upstream reach of the inlet weir+ adjust bed elevaction 2~3 m of upstream reach + dredging a 200m width channel) can increase 1,226 cms. After feasibility assessment, the more feasible improvement case is the case1. The water conveyance benefits of reduce inlet weir height is not significant,and it may increase operation and maintenance costs ,because the floodway operates become more often. The case3 can increase the discharge is the most, but the impacts of human socity, enviroment and laws are too high. It needs long-term planning and evaluation. On the promotion of improvement strategies, it is recommended to promote the removal of the Sanchong and Lujhou landfill lump and desilting at the entrance in the short term. To strengthen manage of the land use,and avoid adding fixed facilities. In the medium term, to promote the dredging of the wetland in front of the inlet weir and adjust downwards bed elevation 2~3m of upstream reach. In the long term, to promote dredging a 200m width channel, but it has lots of impacts. It also need more evaluation and consultation. The strategies of improving water conveyance can provide implementation reference for the relevant agencies.