A methodology based on numerical models for enhancing the resilience to flooding induced by levee breaches in lowland areas

Abstract

Abstract. With the aim of improving resilience to flooding and increasing preparedness to face levee breach-induced inundations, this paper presents a methodology to create a wide database of numerically simulated flooding scenarios due to embankment failures, applicable to any lowland area protected by river levees. The analysis of the detailed spatial and temporal flood data obtained from these hypothetical scenarios is expected to contribute both to the development of civil protection planning, and to immediate action during a possible future flood event (comparable to one of the available simulations in the database), for which a real-time simulation may not be feasible. The most relevant criteria concerning the choice of the mathematical model, the grid resolution, the hydrological conditions, the breach parameters and locations are discussed in detail. Results of the application of the proposed methodology to a 1,100 km2-pilot area in Northern Italy are presented. The creation of a wide database for the study area is made possible thanks to the adoption of a GPU-accelerated shallow water numerical model, which guarantees a great computational efficiency (ratios of physical to computational time up to 80) even for high-resolution meshes (2.5–5 m) and large domains.