Baffle Pier Effects on Hydraulic Performance and Scour Downstream of Sluice Gates

Sluice gates control water levels and discharge them into small irrigation canals. This study examined a modified stilling basin incorporating submerged baffle piers downstream. The study analyzed hydraulic-jump characteristics, energy-dissipation efficiency, velocity distribution patterns, water-level fluctuations, and bed configurations resulting from flow downstream of the sluice gate. The experimental program comprised ninety runs using ten stilling basin models. These models involve various stilling basins with different baffle pier heights and angles, tested under a range of flow conditions. A smooth apron without baffle piers served as the reference case for comparison. Results showed that baffle piers with a height of 12 cm and a 45° angle oriented against the flow optimized stilling basin performance, improving flow characteristics and minimizing bed configuration. This optimal design decreased dimensionless jump length by 45-47%, increased energy dissipation efficiency by 46-60%, and reduced maximum velocity by 33% compared to the smooth apron across the tested Froude number range. Based on these results, a multiple regression analysis was conducted to develop an empirical equation to predict energy dissipation in the modified stilling basins. These findings provide practical design guidelines for optimizing the performance of stilling basins in small irrigation canal systems.