Computation of a flood event using a two dimensional finite element model and its comparison to field data

This paper reports on an attempt to begin a rigorous field testing programme for two dimensional finite element flow models, examining the impacts of mesh resolution and numerical method on simulation results. To achieve this a two dimensional finite element model, TELEMAC-2D, has been applied to an 11 km reach of the River Culm, Devon, UK for which field data concerning discharge and flood inundation were available. This data has been used to assess the performance of two new numerical methods, a Streamline Upwind Petrov Galerkin formulation and a hybrid scheme combining characteristics and centred differences, and a special treatment for flood propagation over initially dry domains that have recently become available within the scheme. This has been achieved for two finite element discretizations consisting of 2040 and 9600 elements. The paper shows progress towards a more complete validation of the scheme and demonstrates a critical need to improve field data capture procedures if such progress is to be sustained.