圖書典藏及影音數位平台

三峽河治理規劃於民國77年完成迄今已逾20年，另於民國100年完成規劃檢討，檢討至今歷經數次颱洪及相關工程措施（三峽橡皮壩於102年4月拆除），河道地形及周邊環境均有變化，依102至104年大斷面測量成果可見三峽河河道持續刷深，為瞭解整體河道水理特性變化及土砂沖淤影響，實有重新檢討三峽河通洪能力及輸砂變動趨勢之必要，以維持河道正常排洪機能，減少兩岸洪災損失，供河川管理及防洪工程實施之依據。

The Sanxia River basin is located at Sanxia District, New Taipei City. The basin area is 198 km2, the mainstream length is about 29km with 1/140 averaging slope. The largest tributary is Heng stream, with 54 km2 drainage area, 12 km long and 1/200 averaging slope. The regulation scheme of Sanxia river has been reviewed in 2011. Typhoon Sura and Soudelor hit Taiwan in 2012 and 2015, and both cause serious damage at Sanxia district. For the concern of flood protection in the Hsiuchuan section, the damaged inflatable rubber dam was removed. Considering the changes in this area, the study examine the regulation scheme of Sanxia river again in compliance with the current situation for the purpose of further river and watershed management. The flood protection standard for the Sanxia river is peak discharge with 100-yr recurrence frequency flood and 1.5-m freeboard. For the Heng stream, it is 50-yr return period peak discharge plus 1.0-m freeboard. After reviewing previous reports, this study suggests to keep using the results of hydrology analysis in 2011. The 100-yr flood discharge is 3,260 cms and 50-yr flood at outlet of Heng stream is 1,360 cms, respectively. Main improvement strategies： 1. Engineering Strategy (1) Embankment building：solving some densely populated areas with its nearby embankment’s altitude is lower than the planned flood altitude. (2) Dredging：evaluating the potential dredging area and handle order. (3) Brifge and Groundsill Works：dredging 2 to 3 meters of riverbed at Sanxia Brifge and Arch Bridge, reaching Hsiuchuan Embankment for 100yrs capability of water conveyance. 2.Non-Engineering Strategy (1)Management：using management methods at unprotected landmarks area. (2)Disaster Resistant Communities：promoting at Hsiuchuan Village and His-Nan Village. (3) Flood warnings system：establishing warning water elevation and warning rainfall (4)Land development comply outflow control：maintaining the sustainable management project with outflow control measures.