圖書典藏及影音數位平台

急水溪流域面積約379平方公里，主流全長約65公里，屬中央管河川。本局治理界點由河口至南一六五線青葉橋全長約47公里，兩側現況防洪構造物興建日期不一，由民國98年「八掌溪及急水溪水系大斷面測量工作」測量報告書統計，現有堤防約為72,541公尺。 現況防洪構造物歷經多年風吹日曬、颱風豪雨後，已有堤頂下陷、淘空滲砂與材料劣化等現象一一發生，對於現況防洪構造物的安全性影響極大。歷經民國98年88水災等沖刷影響之後，造成堤防嚴重受損亟需評估其安全性。然而整河段拆除重建工程經費龐大，為能尋求有效維修與補強方案，擬委外辦理安全性評估分析及研擬改善方案。

The range of ： River Basin is located around Tainan City. The area of this basin is 587 km2. The total length of main river is about 65 km. The length of embankment structure at both banks is about 76 km. The tributary includes the Baishuei Creek, Seintsawpu Creek, Liutsong Creek, Gweitsong Creek and Luliao Creek. It is administrated by the central authority. Its source is near Guanziling in Alishan Range. It flows through Baihe, Dongshan, Houbi, Liouying, Hsinjing, Shiaying, Shiuejia, Yanshuei, and Beimen Districts of Tainan City. It pours into the Taiwan Straits in Beimen District finally. Because of the global climatic anomaly in recent years, the frequency of violent climate is increased. Among them, the Morakot Typhoon brought a surprising rainfall to Taiwan area in 2009. The flow rate exceeded 100-year design standard in many areas. The embankment of Jishuei River Basin was built long ago. The structure is very old. In order to understand the condition of embankment body structure, it is necessary to carry on a total inspection. Because the rebuilt cost of embankment is very huge, so this plan is conducted to seek the most economic maintenance countermeasure by a nondestructive inspection. The contents of planning work comprise the safety inspection of embankments (including field visual investigation and nondestructive inspection), information collection (including the literature collection of background information, trend of riverbed degradation and aggradation, the domestic (foreign) embankment body structure inspection method etc.), review of present channel flood ability, and multimedia briefing. The quantity of project includes three times of visual investigation, 28,218m of nondestructive inspection by ground penetration radar, and 132 places of impact-echo inspection. From the inspection results, it is known that there are 446 damaged places by visual investigation, 1309.5m with slight erosion signal and 36.5m with general erosion signal by ground penetration radar, and 60 places with void signal by impact-echo inspection. The repair priority of embankment is proposed in accordance with the field visual investigation, nondestructive inspection, comprehensive analysis of background information, and whole embankment safety assessment. The results show that 9 embankments are normal, 14 embankments must be improved as plan, 11 embankments must be improved as attention, and no embankment section must be improved at once. But some embankment sections have the damage condition of void and erosion. It is proposed to raise the funds for the repair as quickly as possible. Besides, according to the result of hydraulic calculation, only Sishih embankment does not reach the planned embankment elevation at present, it is recommended to improve it by increasing the breast wall or dredging the riverbed.