Risk-Based Design of Dike Elevation Employing Alternative Enumeration

Abstract

Floods are the most devastating natural disasters and are occurring with increasing frequency and causing losses worldwide. Structural measures have been used as primary tools to control floods and flood losses. Despite devoting considerable resources to structural measures, increasing trends in flood losses and casualties are observed. It is also realized that probability-based design standards are unable to reduce losses efficiently because population dynamics are not taken into consideration. A risk-based approach was introduced in the 1990s in the field of flood management. So far, the implementation of risk-based flood management is lacking due to its inability to provide a uniform standard approach that could be practiced nationwide. The present research provides a risk-based systematic framework for the design of structural measures. The concept of optimum state (OS) is introduced. This framework is based on costs and benefits using expected annual damages (EAD) for the evaluation of flood risk mitigation. EAD addresses the probabilistic nature of flood events and provides risk distributions in the form of EAD curves and EAD distribution maps. The proposed framework supports considering all probable floods instead of a single design flood.