Towards reproducible pluvial flood simulation in urban areas with TELEMAC-2D

The megacity of Lagos, Nigeria, is subject to recurrent severe flood events as a consequence of extreme rainfall. In addition, climate change might exacerbate this problem by increasing rainfall intensities. To study the hazard of pluvial flooding in urban areas, several complex hydraulic models exist with a high demand in terms of required input data, manual preprocessing, and computational power. However, for many regions in the world only insufficient local information is available. Moreover, the complexity of model setup prevents reproducible model initialisation and application. This conference contribution addresses these issues by an example application of the complex hydrodynamic model TELEMAC-2D for the city of Lagos. The complex initialisation procedure is simplified by the new package ‘telemac’ for the statistical environment R. A workflow will be presented that illustrates the functionality of the package and the use of publicly available information, such as free DEMs and Openstreetmap data to cope with the problem of insufficient local information. By further analysis and visualisation procedures along the workflow the increasing hazard of pluvial flooding for Lagos is shown. The workflow makes model initialisation, application, and the analysis of results reproducible and applicable to other regions with a relatively low need for manual user interventions and without additional software other than R and TELEMAC-2D.