Experimental Investigation of Flood Management by an Instantaneous Levee Breach

Laboratory experiments were conducted to investigate the reduction of flood depth in a channel due to an engineered levee breach. Different combinations of inflow hydrographs, breach openings, and floodplain storage areas were considered. Inflow hydrographs with various peak discharges, hydrograph shapes, and flood durations were generated by a computer-controlled valve. A breach was created instantaneously on the channel sidewall as the flood wave approached the breach location. Regression analyses were conducted to express the reduction of flood depth as a function of the breach width, channel width, distance of the selected location from the breach centerline, hydrograph characteristics, and the area of the floodplain basin. The results show that the engineered levee breach provided an effective reduction of flood depth both upstream and downstream of the breach-more so upstream of the breach-by modifying the flood wave. The breach width and floodplain area are found to play a significant role in depth reduction.