Effect of Various Groins in a Series on Channel Bed Morphology: an Experimental Investigation

Alluvial rivers in Bangladesh are unstable keep changing their main channel, banklines, and so on. Groins are extensively used worldwide for shore protection from erosion, river navigation, beach reclamation among many other services. Improving the performance of groins is a crucial issue around the glove. Experimental investigations under clear water scour conditions have been conducted in this research to compare the performance of different groins in order to find out the suitable design of a groin. From the experimental runs, it is revealed that the groin models of different configurations behave in different ways. In the case of a solid I-shaped groin, a huge scour near the groin head and irregular bed pattern develop in the channel bed. While L-head and hockey-shaped groins improve the channel response a bit leading to decreased scour. Moreover, the hockey-shaped groin attracts the flow, and thus requires groin installation closely. The scour hole for a combined groin is relatively very small. As the scour endangers the stability of the groin structure, this turns out to be the most suitable one.