How to study mechanism of avalanche on reservoir bank: a retrospective study

Abstract

Reservoir-bank avalanche is a common hydrogeological problem whether in China or other countries, and analysis for the mechanism of collapse on reservoir bank is an important issue in the field of disaster prevention and mitigation. This paper reviews the methods which had been used to study the mechanism of reservoir-bank avalanche, including field monitoring, field investigation, model or field experiment, and numerical simulation. In virtue of many advantages, e.g., high efficiency and automation, field monitoring has become a powerful tool in evaluating reservoir-bank collapse. Nevertheless, field monitoring is also subject to some external factors related to remote sensing technology, such as weather conditions, environment, and other factors. Field investigation has the characteristics of flexibility and maneuverability. However, a field investigation is a sampling method based the observation in the representative area, and the hazard information cannot be comprehensively obtained via field investigation in the study area. A common merit for the field monitoring and investigation is that data observed with the methods mentioned above may be used to calibrate the results of the model experiment and numerical simulation, but field monitoring or investigation are not applicable to track the process of bank collapse. Different from the monitoring or investigating method, an experiment of reservoir-bank collapse under closely monitored or controlled experimental conditions focuses on the regularities of bank collapse from a micro perspective. The model experiment may be conducted in a laboratory far away from the study area, and the experimental scenario may be freely designed if needed. Yet the researchers should consider the similarity of the cumulative effect while designing the downscaled model experiment for reservoir bank failure. Maybe it is easy to simulate and observe the complicated topographical conditions of bank collapse in the field experiment, because no change exists in the scale of the underlying surface and properties of erosion material. In fact, usually to make accurate observations and simulations is relatively difficult in the field. Numerical simulations have been widely used to analyze and predict the reservoir-bank avalanche from a macro perspective all over the world, whereas the result of the numerical simulation has to be verified with that obtained from monitoring, investigation or experiment. In summary, each research method presents its own characteristic set of advantages and limitations. Scientists may use an appropriate route for analysis according to objectives and contents of a specific project.

Key words: Reservoir-bank avalanche; Field monitoring; Field investigation; Model experiment; Numerical simulation