| Summary: | 碩士 === 國立屏東科技大學 === 水土保持系所 === 105 === Groundsills have been implemented in river regulation. However, local scour at the toe of groundsill is unable to avoid neither with the modification of groundsill nor with riprap. Hence, installation of groundsills hardly meets the objective of eco-friendly environment. This study is based upon 1:50 scaled model experiments using 3 sediment sizes, 3 flow rates and 3 channel gradients. Preliminary results indicate that permeable groundsill can effectively control the scour depth, and extent of the scour. When the permeability of groundsill is set at 7% while holding model sediment size at 1.05 mm, the extent and volume of local scour can be reduced by 6~38% and 17~62%, respectively; whereas, the volume of sediment deposition can be reduced by 8~83%. At 68% permeability, the extent, volume of local scour, and that of deposition can be reduced by 6~54%, 11~79%, and 26~57% accordingly. However, permeability of the structure gradually decreases and resumes its functions similar to that of the traditional groundsill.
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