Risk management in maritime structures

Abstract

Maritime structures (breakwaters, groynes, ocean wave/wind energy converters, etc.) are exposed towave attack, which generates common emergency situations with serious environmental and economic consequences. This paper presents a methodology developed at LNEC for forecasting and early warning of wave overtopping in ports/coastal areas to prevent emergency situations and support their management and the long-term planning of interventions in the study area. It is implemented in a risk management tool. The methodology uses numerical models to propagate waves from offshore to port/coastal areas to obtain the required input for overtopping assessment methods, such as empirical formulas and artificial neural networks. The calculated overtopping values are compared with pre-established admissible values in order to define the warning levels. These admissible values are derived from general international recommendations and information from local authorities. They depend on the characteristics of the overtopped structure and of the protected area, and on the activities developed there. The warning methodology is applied to Praia da Vitória Port (Azores-Portugal) as an illustrative example. Future developments include the use of complex numerical models (e.g. Navier-Stokes equations solvers; particle methods) to calculate wave overtopping and to extend the methodology to warn of risks associated with wave energy production failure.