SCOURING AROUND SPUR-DIKES IN ALLUVIAL FLOODPLAIN RIVERS

Abstract

Characteristics of bank shape along approach channels at upstream reaches of spur-dikes in alluvial floodplain rivers of Bangladesh are investigated. The shape of river bank at approach channel sections are found to be non-rectangular that can be approximated as nearly trapezoidal. Available methods for the prediction of maximum local scour depth around spur-dikes are not capable to handle such problems where cross sectional shapes in approach flows are different from rectangular. Therefore, an analytical model is developed incorporating the variation of cross sectional shape of approach channels and applied to some of the spur-dikes along the alluvial floodplain rivers.