Impulse waves in reservoirs generated by landslides into shallow water

Abstract

Landslides sliding into shallow water often block watercourses, and in addition landslide-induced impulse waves may result in risks to the safety of the reservoir or waterways over a wide area. Such impulse waves differ from those from landslides into deep water which slide underwater completely. This study conducted twenty-five groups of orthogonal experiments of landslide-induced impulse waves in shallow water where the Froude numbers ranged between 0.6 and 2.0. Based on the experimental results, dimensionless functions of the parameters such as amplitude, wavelength and jet-flow height of the initial landslide-induced waves in shallow water were derived. The predictions from these formulae are very close to those obtained from the experiments. Further, a source model of landslide-induced waves in shallow water was built based on formulae derived from the experiments, and wave propagation and run-up were calculated with the Boussinesq-type equations model. The newly built model of landslide-induced waves in shallow water was used to calculate and analyze two representative examples from landslides in the Three Gorges in China, namely the Qianjiangping landslide-induced impulse wave event and the Xintan landslide-induced impulse wave event. Comparison of the calculations with data from multiple sources indicated that our model for landslide-induced waves in shallow water had high accuracy. Our model for landslide-induced waves in shallow water may help in the predictive analysis of impulse waves and mitigation works for this type of event in reservoirs worldwide.