XBEACH IMPLEMENTATION IN THE NEW NATIONAL COASTAL FLOOD RISK ASSESSMENT FRAMEWORK FOR THE DUTCH COAST

Abstract

Dunes and beaches protect large stretches of the Dutch coast against flooding from the sea. As prescribed by the Dutch Water Law, the Dutch dune coast is periodically assessed to ensure an acceptable level of flood risk in the hinterland. This safety assessment methodology is currently being renewed within the framework of the BOI program (Assessment and Design Instruments for flood defenses) to utilize the process-based storm impact model XBeach as replacement of the empirical dune erosion model DUROS+. The project consists of six steps: 1. XBeach model formulation improvements and model robustness, 2. XBeach calibration, 3. XBeach validation, 4. derivation of semi-probabilistic model input for the Dutch coast, 5. derivation of a failure definition and 6. implementing XBeach in a renewed flood risk assessment framework (Wilmink et al., 2020). The main goal of the project is to increase the accuracy of the flood risk assessment of dunes in the Netherlands by implementing XBeach as dune erosion model and develop a user-friendly GUI and guideline for the assessment framework.