Flood risk and economically optimal safety targets for coastal flood defense systems

A front defense can improve the reliability of a rear defense in a coastal flood defense system. The influence of this interdependency on the accompanying economically optimal safety targets of both front and rear defense is investigated. The results preliminary suggest that the optimal safety level of a coastal flood defense system can only be improved with a combination of front and rear defense if for a similar risk reduction, the front defense investment is cheaper than the rear defense. If a case needs a more complex risk and economic optimization model, the simplified approach is no longer applicable and a computational framework is recommended. Nevertheless, the simplified approach offers a fast, first order assessment of the economically optimal safety targets for coastal flood defense systems.