The Importance of Digital Elevation Model Selection in Flood Simulation and a Proposed Method to Reduce DEM Errors: A Case Study in Shanghai

Abstract Digital Elevation Models (DEMs) play a critical role in hydrologic and hydraulic modeling. Flood inundation mapping is highly dependent on the accuracy of DEMs. Various vertical differences exist among open access DEMs as they use various observation satellites algorithms. The problem particularly acute small, flat coastal cities. Thus, it necessary to assess input flood simulation reduce anomalous errors In this study, we first conducted urban Huangpu River Basin Shanghai by using LISFLOOD-FP hydrodynamic model six open-access (SRTM, MERIT, CoastalDEM, GDEM, NASADEM, AW3D30), analyzed results simulations. Then, processed two statistically based methods compared with those original show that: (1) mappings are significantly different under same conditions—this indicates that only single DEM dataset may lead bias not adequate for high confidence analysis exposure management; (2) corrected Dixon criterion predicting extent improved, addition reducing extreme water depths—this datasets have some performance improvement simulation. A freely available, accurate, high-resolution needed support robust mapping. Flood-related researchers, practitioners, other stakeholders should pay attention uncertainty caused quality.