Effects of DEM resolution and resampling technique on building treatment for urban inundation modeling: a case study for the 2016 flooding of the HUST campus in Wuhan

In China, flood inundation modeling is often limited by the lack of high quality topographic dataset, especially in small cities where hydrologic informatization is relatively backward. Coarse-resolution digital elevation models (DEMs) often lead to lower accuracy in simulation results due to the loss of small-scale building features in terrain modeling. Increasing the DEM resolution by resampling techniques may be an available solution to building representation problems in data-sparse areas, which has not yet received much attention and needs to be tested in conjunction with urban inundation models. This paper evaluated the impact of DEM resolution and resampling techniques on the building treatment method (BTM) and the output of urban inundation model to determine whether satisfactory inundation simulation can be achieved based on resampled DEMs with fine resolution. Using the 2016 flood event in Wuhan as the study case, a detailed comparison among 19 modeling scenarios differing in DEM resolutions, resampling techniques and BTMs was subsequently conducted. The outcome of the comparison analysis revealed the sensitivity of the simulated inundation depth to the resampled DEM resolution. Furthermore, the scenario using resampled DEMs with high resolution showed better performance in urban inundation modeling because the building features and the flow paths within building gaps were adequately represented by the BTM. The findings of this study may facilitate the application of BTMs for urban inundation modeling to predict (with useful accuracy) the inundation extent and depth in areas where fine topography data are unavailable.