Effect of Dam Height on Breaching due to Overtopping of Non-Cohesive Earthen Dams

The studies on dam breaches due to overtopping have recently increased as breaches have had devastating impacts on urban and rural communities. The ability to predict and understand the breaching process is critical for flood-damage mitigation, emergency planning, and evacuation. Experiments on dam breaching due to overtopping were run on non-cohesive model embankments of heights varying between 10 cm and 45 cm. Experiments were performed in a 1-m-wide and 1.2-m-high flume in the Hydraulics Laboratory at the University of South Carolina. The dams were built in 5-cm lifts with equal compaction. Slopes equal to 3H:1V were cut to create the final dam shape. A pump provided a constant discharge, and an overflow weir was used to maintain a constant water level in the upstream reservoir. A rectangular pilot channel of 2.5 cm in width and 1.9 cm in depth was used to initiate the breach over the center of the dam. Preliminary results show that failure timing depends on dam height.