River restoration aims to apply environmentally-friendly structures for bank protection in meandering rivers to restore their natural habitat. Enhanced Permeable Groin (EPG) is a novel river restoration technique that can improve the fish habitat environment in a river system by creating a series of eco-friendly scour pools. This study reports the results of two groups of 3D velocity measurements in a 180-degree channel bend in cases with and without an EPG for clear water conditions to characterize the mechanisms leading to the primary stages of the scouring phenomenon. The analysis revealed that the presence of an EPG amplified the velocity magnitude in the regions near the tip of the vane and increased its value in the middle of the channel 1.13 times the bend without the structure. In addition, the comparison showed that the EPG reduced the velocity magnitude in the recirculation zone by an average of 38%. Secondary currents including main and outer bank cells were observed in the case without the structure. The presence of the EPG in the flow field effectively increased the outer-bank cell strength by 11 times compared to that without the structure. The low-value contours of the bed shear stresses were observed in the zone downstream of the structure for a distance of 6 times the effective length of the structure. Based on the results of this study, the generation of a recirculation zone with low-velocity and shear stress values can provide suitable conditions for aquatic habitats, deep-bodied fish assemblages, aquatic vegetation, shrub roots, and tree roots along the outer bank.

河流修复旨在在蜿蜒的河流中应用环保结构保护河岸，以恢复其自然栖息地。增强渗透腹股沟（EPG）是一种新颖的河流修复技术，可以通过创建一系列生态友好型冲刷池来改善河流系统中的鱼类栖息环境。本研究报告了在有和没有 EPG 的情况下，在 180 度通道弯曲的情况下，在清水条件下两组 3D 速度测量的结果，以表征导致冲刷现象初级阶段的机制。分析表明，EPG 的存在放大了叶片尖端附近区域的速度幅度，并使其在通道中间的值增加了 1.13 倍于没有结构的弯道。此外，比较表明，EPG 将再循环区的速度幅度平均降低了 38%。在没有该结构的情况下，观察到包括主库和外库的次级电流。流场中EPG的存在有效地使外岸细胞强度比没有结构的情况下增加了11倍。在结构有效长度的 6 倍处，在结构下游区域观察到床层剪应力的低值轮廓。根据本研究的结果，低速和剪切应力值的再循环带的产生可以为外岸的水生生境、深体鱼类群落、水生植被、灌木根和树根提供适宜的条件。