Experimental Study on the Performance of Slope-crested Groynes in Erodible Meandering Channels of Different Sinuosity

Abstract

Riverbank erosion is a vital issue in the management and restoration of rivers, especially in alluvial meandering channels because of their unique channel morpho-dynamics. Various countermeasures are thus implemented to minimize riverbank erosion and maintain stable channel sections of meandering channels. This study analyzes the performance of modified impermeable groynes with sloped crests as a countermeasure for bank erosion. Experiments were conducted in erodible meandering channels of two different sinuosities to evaluate the performance of the proposed countermeasures under varying sinuosity as well as analyze the overall morphological evolution of the channel. The results show that the low sinuosity (LS) channel was more prone to erosion compared to the higher sinuosity (HS) channel. Channel sinuosity also affected the overall channel morphological evolution with the LS channel showing more distinct characteristics of a meandering channel forming point bar and pool and riffle sequences. The proposed countermeasure showed slightly better performance in the case of the LS channel. Although the presence of the proposed groynes did not significantly deflect the high-velocity core towards the channel center, the velocity near the bank region was significantly reduced.