A conceptual model for spatially regulating debris flow materials and energy by cascading check dams based on flume experiments

Debris flows are associated with large amounts of sediment transport and dramatic energy shift, which seriously threatens the safety of human lives and infrastructure along their paths. Check dams, especially cascading check dams, can effectively mitigate debris flow hazards. However, how the solid material and energy of debris flows are regulated by the spatial distribution of cascading check dams is unclear. In this study, flume experiments were conducted to analyze the effects of different spacings and numbers of check dams on the material transport and energy regulation of debris flows. Changes in the functional parameters regulating debris flows, such as the trapping efficiency, kinetic energy attenuation rate, potential energy storage ratio and total energy loss ratio, were revealed for cascading check dams. Both the trapping efficiency and kinetic energy attenuation rate increased with increasing dam number, reaching maximum values of 0.88 and 0.94, respectively. Furthermore, the relationship between the functional parameters regulating the debris flow and the relative height difference along the channel were effectively described by an exponential function. Finally, a conceptual model was established to spatially regulate the sediment distribution and energy dissipation of debris flows by cascading check dams, and a relative height difference of 7.25 was the critical maximum empirical value for effective regulation of the debris flow models in this experiment.