2D analysis for local flooding assessment in a new square of Barcelona during storm events

The problem of urban flooding requires a deep knowledge in some specific fields (flow modelling, hydraulic efficiency of surface drainage structures, topographic information with detailed scale, etc.). In this paper, a specific case study is considered: the Fira Square of Barcelona. Due to esthetical and architectonic reasons, the square was designed to be highly impervious and does not present any curb or clear thalwegs and gradients capable to direct runoff produced during storm events towards specific points. In order to collect the runoff produced during storm events, 4 series of continuous transverse grates were located in this area according to the ground morphology, but their hydraulic efficiency was never studied. The aim of this work was to study the hydraulic behaviour of the square during heavy rains. In order to reach this goal a detailed digital elevation model was elaborated and the transverse grates hydraulic efficiency was empirically determined in the UPC laboratories. Finally UNICAL used an own two dimensional code for numerical simulation in order to test the hydraulic behaviour of the square during storm events and provided risk maps related to flow depth and velocities.