Solitary Impulse Wave Transformation to Overland Flow

Impulse waves are generated by avalanches, landslides, rock slides, rock falls, or glacier calving impact into natural lakes or reservoirs. Similar to tsunamis, the generated long waves imply a large damage potential to the surrounding infrastructure and settlements. The current hazard assessment is mainly limited to plane wave run-up because previous studies were related to linearly inclined slopes. The presented study therefore focuses on solitary impulse wave-induced overland flow on a horizontal shore. Physical experiments involved a two-dimensional test setup in a wave channel including a piston-type wave generator and an inclined shore with a connected horizontal overland flow plane. Particular focus is given to the transition from the inclined to the horizontal portion, where the orbital wave motion is transformed into a shore-parallel flow. The overland flow features were investigated by means of ultrasonic distance sensors and particle image velocimetry for various values of relative wave height, shore slope, and freeboard. Prediction equations are specified for the maximum flow depths, flow velocities, and the maximum discharge. (C) 2014 American Society of Civil Engineers.