Estimating Optimal Design Factors of Reverse-Wedge Hole Type Labyrinth Weir for Exclusion of Sediments

Various transverse artificial structures have been constructed in rivers and streams. A weir, one of representative transverse structures, plays a significant role in maintaining the upstream depth of water and securing water resources. However, it has generic disadvantage of undermining sediment continuity due to sediment deposition at direct upstream of weir. Because of these things, ecosystems of the weir downstream could be effected or disturbed. In this study a trapezoidal Labyrinth weir was modified to increase sediment exclusion efficiency upstream, called as the Sediment Exclusion Labyrinth weir (SEL weir). Various effective factors, the ratio of hole area (a/A), the hole number (n) and the ratio of height of holes and weir (), were examined in order to find optimal design factor with numerical simulation. As numerical results, when the ratio of hole area was less than 0.069, the reduction rate of upstream height was less than 3.0%, where the upstream water depth was approximately was maintained. When the hole numbers became 4, the maximum accumulated sediment exclusion efficiency was occurred. However, the role of hole number was not played important to accumulated sediment exclusion efficiency. And the maximum accumulated sediment exclusion efficiency was occurred at $h_{hole}/h_w