Raster Based Model of Inland Coastal Flooding Propagation Using Linearized Bottom Friction and Application to a Real Case Study in Caorle, Venice (IT)

摘要

The paper presents a flood propagation model just developed by theauthors, raster based and suited to very large maps (i.e. regional ornational scale). The finite-difference model solves a simplified form ofthe shallow water equations, accounting for a linearized bottom frictionand removing the convective acceleration terms. Each grid cell of themap is treated as an individual storage volume element and a simplifiedmomentum equation is used to calculate the inter-cell fluxes.The computational efficiency is one of the key issue of inundationmodels applied to hyper-resolution maps. In order to increase thecomputational speed and the memory capacity, a TESLA K80 GPUaccelerator with 4992 Nvidia CUDA cores and 12 GByte memory isused.The model is firstly tested against a well-known benchmark and thenapplied to a case study, i.e. the coastal flooding of Caorle area, Venice(IT) occurred in December, 2008. Flooding was caused by overtoppingof waves propagating up the Livenza river mouth. The availableinformation includes the incident wave conditions during the stormevent, the water level inside the river mouth, and newspaper reports,pictures and video documenting the flooded area.The proposed inundation model has the ambition to help the coastalmanager and stakeholders in producing flooding risk maps requiredunder the EU water flood directive. In fact, using a raster basedapproach, the model is also suited to be integrated in a GeographicalInformation System (GIS) platform in a form that is readily applicableby the stakeholders with the most recent Digital Elevation Models(DEMs).