The construction of fully closed check dam (CD) is a conventional flood prevention mechanism implemented on rivers. Fully closed CDs trap large amounts of sediments in rivers to stabilize the river slopes and control ...The construction of fully closed check dam (CD) is a conventional flood prevention mechanism implemented on rivers. Fully closed CDs trap large amounts of sediments in rivers to stabilize the river slopes and control erosion. However, fully closed CDs cannot selectively trap sediment and may easily overflow, causing them to losing their ability to mediate and hold sediments. Previous studies proposed the concept of “breathable CDs”. The researcher introduced metal slit dam (SD) that could be assembled and disassembled quickly and conveniently. Once a CD reaches maximum capacity, operators must ensure that the water channels of the dam are free from blockage. Moreover, they must inspect the internal accumulation conditions of the dam periodically or immediately following heavy typhoon rains. When necessary, either the sediment buildup in the upriver blockage must be cleared, or the transverse structure of the dam must be removed to allow fine particles to be discharged along with a moderate amount of water. These actions can free up the sediment-storing capacity of the dam for the next heavy typhoon rains. In addition, operators should also inspect the damages inflicted on the dam, such as erosion, wear and tear, and deformation conditions. Damaged components should be disassembled and repaired if possible, or recycled and reused. The present study performed channel tests to simulate closed CDs, SDs, steel pipe dam (SPDs), and steel pipe plus slit dam (SPSDs) for 50-year and 100-year frequency floods. Results were then analyzed to determine the sediment trapping (ST) effects of various CDs, the effects of “adjustable CDs”, and the changes of moderated riverbeds.展开更多
Due to effects of succession typhoons and heavy rainfall, central government often invests the funds within shortest time of contingency promptly after disaster occurring to handle the planning and design project of t...Due to effects of succession typhoons and heavy rainfall, central government often invests the funds within shortest time of contingency promptly after disaster occurring to handle the planning and design project of taking precautions against natural disaster. Because the time limit of design project operating so generally were planned without many detail investigations, it was necessary to probe into the project effect and reconstruction security behind constructed. In this study, we choose the Meizuolyu stream watershed in Taitung County of eastern Taiwan as the research area to realize the situation and effect of setting up the control work reconstructions by inspecting, surveying and according to hydrology analysis and topography measured, and combined to carry on hydrology mathematical calculations. We adopted HEC-RAS software to make hydrology mathematical calculations, used the result to examine whether the position of each construction was proper, and finally submitted the complete of mend suggestion. The study concluded that no matter how urgent governance was, application of appropriate scientific tools to checklist designed could avoid the mistakes of the generation.展开更多
文摘The construction of fully closed check dam (CD) is a conventional flood prevention mechanism implemented on rivers. Fully closed CDs trap large amounts of sediments in rivers to stabilize the river slopes and control erosion. However, fully closed CDs cannot selectively trap sediment and may easily overflow, causing them to losing their ability to mediate and hold sediments. Previous studies proposed the concept of “breathable CDs”. The researcher introduced metal slit dam (SD) that could be assembled and disassembled quickly and conveniently. Once a CD reaches maximum capacity, operators must ensure that the water channels of the dam are free from blockage. Moreover, they must inspect the internal accumulation conditions of the dam periodically or immediately following heavy typhoon rains. When necessary, either the sediment buildup in the upriver blockage must be cleared, or the transverse structure of the dam must be removed to allow fine particles to be discharged along with a moderate amount of water. These actions can free up the sediment-storing capacity of the dam for the next heavy typhoon rains. In addition, operators should also inspect the damages inflicted on the dam, such as erosion, wear and tear, and deformation conditions. Damaged components should be disassembled and repaired if possible, or recycled and reused. The present study performed channel tests to simulate closed CDs, SDs, steel pipe dam (SPDs), and steel pipe plus slit dam (SPSDs) for 50-year and 100-year frequency floods. Results were then analyzed to determine the sediment trapping (ST) effects of various CDs, the effects of “adjustable CDs”, and the changes of moderated riverbeds.
文摘Due to effects of succession typhoons and heavy rainfall, central government often invests the funds within shortest time of contingency promptly after disaster occurring to handle the planning and design project of taking precautions against natural disaster. Because the time limit of design project operating so generally were planned without many detail investigations, it was necessary to probe into the project effect and reconstruction security behind constructed. In this study, we choose the Meizuolyu stream watershed in Taitung County of eastern Taiwan as the research area to realize the situation and effect of setting up the control work reconstructions by inspecting, surveying and according to hydrology analysis and topography measured, and combined to carry on hydrology mathematical calculations. We adopted HEC-RAS software to make hydrology mathematical calculations, used the result to examine whether the position of each construction was proper, and finally submitted the complete of mend suggestion. The study concluded that no matter how urgent governance was, application of appropriate scientific tools to checklist designed could avoid the mistakes of the generation.
