Assessment of flood risks in Pearl River Delta due to levee breaching

Abstract

A levee system may pose enormous risks to the people protected by the system. Risk analysis is at the heart of levee risk mitigation and engineering decision-making. An explicit methodology for the analysis of flood risk due to levee breaching is desirable. In this paper, a case study on the risks of the North Pearl River Levee System (NPRLS) in Guangdong Province, China, is conducted to illustrate an explicit procedure of flood risk analysis. The performance of the levee upon a 100-year flood at milestone 7 +330 near Shijiao is evaluated. The failure probabilities are evaluated for three failure modes: overtopping, piping and slope sliding. The flood scenario resulted from a levee breach in a 100-year flood event at water level 15.5 m above the mean sea level is simulated. The fatality rate is estimated using a model for estimating the vulnerability of human lives in floods based on Bayesian networks, HURAM. The conditional loss of life is finally estimated according to the risk analysis procedure and the fatality rates from HURAM. Possible measures to mitigate the risks of the levee are also discussed.

Keywords:

• dikes
• levees
• risk analysis
• flood risk analysis and management
• seepage
• slope stability

Acknowledgements

The work reported was substantially supported by the National Science Foundation of China (Grant No. 51129902). The constructive comments from two anonymous reviewers are gratefully acknowledged.