Improving the Accuracy of Prediction of Breach Formation through Embankment Dams and Flood Embankments

Embankments are constructed for the retention of water for irrigation and supply, and for protecting people, land, and property from flooding. Failure of any embankment poses risks to people and property nearby and the services provided by the embankment. The review of breaching of embankments in this paper identifies significant issues in the parameterisation of the processes in existing models and the data used for calibration. This paper describes the development of a new model the failure of an embankment that can simulate breach formation, and hence consequent risks, more reliably than existing models. The model uses the standard principles of hydraulics, sediment transport and soil mechanics and introduces a new methodology to model the lateral growth of the breach based upon a combination of continuous erosion and mass instability. The model can simulate the failure of different embankments, either homogeneous or composite, by overtopping or piping, and includes a probabilistic distribution for simulating embankment condition and soil parameters. The model has been tested using both experimental and real failure data, with modelling results showing reasonable agreement with observed values for a range of different scenarios. (Mohamed, 2002) has revealed the several weaknesses and gaps within the modelling process, which are discussed in the sections below. 2.1 Breach Initiation Little quantitative information is known about the breach initiation processes for overtopping or piping failure. Determining how the breach initiates will help in reliably determining how long it takes for a breach to develop to a critical point. This in turn can help emergency planners in establishing flood risk and potential warning times for areas downstream of an embankment.