Backwater prediction due to the blockage caused by a single, submerged spur dike in an open channel

A method is proposed for predicting the backwater effect due to a single, submerged spur dike located within an open channel flow. A theoretical analysis based on the momentum principle relates the backwater effect to the drag force exerted by the spur dike on the flow. Experimental data obtained in laboratory flumes having subcritical flow conditions throughout the flow field have been used in developing predictive relationships for the spur dike drag coefficient, which is found to be strongly correlated to the blockage created by the spur dike within the flow cross section. The predictive relationships provide a means of obtaining a first-level estimate of the backwater effect due to a single, submerged spur dike in an open channel flow.