An experimental study to control bed erosion at river confluence

TLDR: In this paper, circular pile models are suggested as scour reducing structures at river confluences and are studied experimentally and shown to be effective for reducing bed scour and possibly bank erosion.

Abstract: River confluence is a region of merging of two flows of different flow characteristics and sediment loads that result in complex hydrodynamics. The momentum transfer from lateral flow and the flow acceleration causes flow constriction resulting in bed and bank erosion. In this study, circular pile models are suggested as scour reducing structures at river confluences and are studied experimentally. From the scour depth contour maps, it was observed that the bed profiles are remarkably modified with installation of the pile models within the confluence. The scour depth was reduced by 28% with installation of pile models of 12mm diameter at a spacing of 2h. When pile models of 8mm diameter are placed at 2h spacing, the scour depth decreases by 26%. Therefore, the present study shows that pile models are effective for reducing bed scour and possibly bank erosion at confluences.