Large scale modelling of urban floods and 2D shallow-water model with porosity

A two-dimensional shallow-water model is presented for the simulation of urban floods. The concept of porosity is used to account for the influence of the buildings on the flow patterns in the street network without a need for a refined grid. A specific head loss formulation is used to represent singular head losses at crossroads. This model allows the main features of the flow to be represented both inside and outside the urban area while the computational effort is reduced significantly compared to a classical two-dimensional model. The singular head loss term is expressed as a junction of the geometry of the street network, which makes its estimate and calibration easier