RISK ASSESSMENT FOR COASTAL AND TIDAL DEFENCE SCHEMES

This paper describes risk assessment techniques developed in a research project carried out for the UK National Rivers Authority (NRA) (Meadowcroft and Reeve, 1993). The main aim is to develop probabilistic design and analysis methods to assess the risks of failure for new and existing sea and tidal defence schemes. The flood risk takes account of the failure probability and the consequences of failure. There is a contrast between conservative design criteria that attempt to minimise failure rates, and risk-based design criteria that offer a more cost-effective solution despite a possible increase in failure frequency. The procedures are intended to be used in the design of new schemes, for assessment of existing defences and prioritisation of maintenance and refurbishment.