可動堡 設置에 따른 河床變動 豫測에 關한 硏究

Abstract

To estimate the change of riverbed geography by the operation of movable weir, two-dimensional RMA-2 and SED-2D were used in this study. Hydraulic elements like flowrate or depth were simulated by RMA-2 and the change of riverbed geography according to sediment transport was simulated by SED-2D. Suktop stream was chosen as a project river for the simulation. Under the condition of 50-year rainfall frequency, the estimated flood of Suktop was 123cms. At the points of movable weir the simulation results showed that the difference of high water level from the result of HEC-RAS was less than 0.64m. And the difference of water velocity was less than 0.21m/sec. Based on the sediment simulation by SED-2D, predicted riverbed elevation was 29.70-30.22m at the point of ST1 and 28.26～28.82m at the point of ST2. Measured riverbed elevation was 29.70～30.16m, 28.28～28.69m, respectively. So, the predicted elevations are closely similar to the measured elevation. At the point of ST1, sediment transport simulation results showed that erosion of riverbed was predicted by the operation of movable weir. This erosion was ranged up to 200m upstream and the riverbed would be eroded away as much as 0.07m for one year. At the point of ST2, upstream of movable weir would be eroded and the erosion depth was estimated 0.261m. The erosion was higher at the point of movable weir and the erosion depth was estimated 0.310m. But the sediment would be deposit downstream of the movable weir. SED-2D followed by RMA-2 is well applicable to the stream which has movable weirs and can estimate not only hydraulic parameters such as flowrate or depth but also riverbed elevation change caused by erosion or deposit of fluvial sediment.