Efficient and Automated Mesh Generation for Refined Flood Modeling in Complex Urban Environments

Accurate two-dimensional hydrodynamic flood modeling in urban environments requires mesh resolutions that can capture complex flow patterns around buildings and infrastructure, while maintaining computational efficiency. However, generating suitable meshes for such applications is often time-consuming, mainly due to the complex layout of buildings in urban areas. This contribution presents an efficient and automated mesh generation workflow tailored for refined 2D flood modeling in complex urban areas. The approach introduces rule-based local mesh refinements around buildings, flow paths, and critical urban features, while maintaining a coarse resolution elsewhere. First, geometrical input data sets, such as building outlines or water body outlines, are preprocessed to ensure their geometric validity. The building geometry data set is then further analyzed and processed to ensure a refined, yet not excessive, mesh resolution between buildings, taking into account user-given thresholds for mesh resolution. Finally, the mesh is generated based on the processed input data using the Triangle mesher developed by Shewchuck (1996). The framework is designed to be automated yet user-controlled, enabling reproducible and scalable mesh generation for urban flood hazard assessment. Its performance is demonstrated through application to an urban test case in Majalaya, Indonesia, highlighting improvements in accuracy–efficiency trade-offs and suitability for operational flood risk modeling.

Reference:

Shewchuk, J. R.: Triangle: Engineering a 2D Quality Mesh Generator and Delaunay Triangulator, in: Applied Computational Geometry: Towards Geometric Engineering, edited by Lin, M. C. and Manocha, D., vol. 1148 of Lecture Notes in Computer Science, pp. 203–222, Springer-Verlag, from the First ACM Workshop on Applied Computational Geometry, 1996.