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

• 作者: Kepeng Xu Jiayi Fang Yongqiang Fang Qinke Sun Chengbo Wu Min Liu
• 来源期刊: 国际灾害风险科学学报（英文版）
• 年，卷（期）: 2021,（6）
• 所属期刊栏目: ARTICLES
• 页码范围: 890-902
• 页数: 13页
• 语种: 英文

摘要

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