Assessing the Sensitivity of Pluvial Flood Modelling to the Topographic Description of Urban Areas

The rising frequency of pluvial flooding, driven by climate change and rapid urbanization, has increased the vulnerability of urban communities to flood-related hazards. Urban expansion intensifies this issue by reducing soil permeability and altering natural drainage patterns, resulting in more severe flood events that impact larger populations. Consequently, pluvial flooding has become a pressing concern in urban flood risk management. While advanced models have been developed to simulate pluvial flood scenarios, persistent challenges related to input data limit their effectiveness. These challenges fall into four main categories: Data Availability and Integration: Urban flooding involves interconnected systems that require diverse datasets, including topography, land use, and hydraulic characteristics. Accessing accurate and complete data on urban drainage systems is often difficult. Moreover, integrating data from multiple sources and ensuring compatibility across formats adds complexity Data Acquisition and Homogeneity: Continuous data collection using consistent instrumentation is essential. Disruptions or inconsistencies in acquisition can compromise model accuracy and decision-making. Addressing this requires robust maintenance and sensor networks Data Quality, Accuracy, and Uncertainty: Data from various platforms may contain random errors, biases, and uncertainties. Rigorous validation and calibration are necessary to enhance the reliability of simulation outputs and the effectiveness of flood mitigation strategies Spatial and Temporal Resolution: Urban flood dynamics depend on variables such as rainfall intensity, land surface properties, and drainage network behavior. However, acquiring data with sufficient resolution remains challenging, as conventional datasets often lack the granularity needed for accurate modelling These limitations affect a range of input data, including rainfall, sewer systems, and terrain descriptions. This study focuses on the influence of spatial resolution and detail in Digital Terrain Models (DTMs) and Digital Surface Models (DSMs) on the performance of pluvial flood simulations. Using geospatial data processing and 2D flood modelling, the research assesses how different resolutions impact simulation outcomes. The subsurface drainage network is excluded, as the sewer data from the Municipality of Genoa and the local water utility are outdated, shifting the focus to terrain representation.