Modelling of pluvial flooding at local scales

The urbanization, and consequently, the high degree of impermeability of urban areas, along with the effects of climate change, are increasing the flooding occurrence in cities and its consequences during severe rainfall events. The AA-FLOODS project works in the modeling of torrential rains runoff at local scale for different settlements in Andalucía (Spain). One of the main tasks of the project is to build numerical models of the settlements which allow to locate the areas with an important risk of flooding and to find problematic zones of the urban drainage networks. With the information obtained in the models, an accurate elaboration of prevention and crisis management plans caused by floods is possible.

The Water and Environmental Engineering Group (GEAMA) of the University of A Coruña is the AA-FLOODS partner in charge of the hydraulic modeling tasks. The models are carried out using the software Iber-SWMM (Sañudo et al. 2020) developed by the GEAMA. Iber-SWMM is a free distribution dual drainage model which links the models Iber (2D overland flow model) and SWMM (1D sewer network model). The model considers the main hydrological and hydraulic processes during a rainfall event. Iber-SWMM allows a complete analysis of the flood area extension due to the two-directional exchange implemented between the surface and the sewer system. By feeding the software with a digital elevation model, land uses, sewer network information and a set of rainfall events, the user can compute depth maps and potential flooding areas, as well as the values of the hydraulic variables in the sewer network. These results are the basis for the elaboration of prevention and crisis management plans. The model is fully validated for a similar settlement to those of the AA-FLOODS, located, all of them, in the region of Andalucía (Spain).