A Hydraulic Structure for Taking Water and Reducing Sand Disasters

Torrent-intake is established as an effective means to develop water resources for agricultural and residential use. In this study the basic principle of separating water and sand of torrent-intake was applied to develop a new hydraulic structure, combining a bar-screen type torrent-intake with a debris-dam that can take water and reduce flood disasters simultaneously. Firstly, the conventional discharge calculation equation is modified to make the intake discharge calculated values agree with the experimental results, due to the discharge coefficient values calculated by the conventional discharge calculation equation which fluctuated widely while changing the setting angle, the gap width, and the length of the bar-screen. Secondly, gravel is put into the flow to create floods and overflow the debris-dam to downstream while changing the gap width of the bar-screen. The results show that taking water from the flood not only reduces the potential for flood disasters by forcing the gravel accumulates in the streams downstream, but also utilizes the intake water and sand, which flow from the torrent-intake collecting ditch that are separated by the sand-trap. The sand-trap has the structure with a vortex tube set up at the bottom to eliminate the accumulated sand and gravel by the flow.