Local Scour at Floodplain of Compound Channel

Scour around structure is a well known problem for engineers around the world. It has been studied extensively for a long time as a serious threat to human life. It also causes sever structural damage and huge economical loss. Most of rivers in Bangladesh are compound in nature and alluvial. Pier like structures are often constructed at floodplain of compound channel which are also subjected to local scour and may cause failure of structure. This current experimental research has been carried out to investigate general behavior of local scour around pier like structure at floodplain of compound channel. Also effect of river bed material on local scour and comparison with main channel local scour characteristics was studied. Scour map, velocity profile and contour map, bed profile and 3D perspective plots were used for analysis. An empirical relationship was developed using experimental data to predict floodplain scour depth. Proposed equation has been compared with available scour equations. This work will help engineers and designers to estimate local scour, scour type and extent and to design structures such as bridge pier, foundation of river crossing towers at floodplain.