Evaluation of DEM Accuracy and Mesh Resolution in 2D Hydraulic Flood Modeling

Document Type : Original Article

Authors

1 Faculty of Civil, Water, and Environmental Engineering, Shahid Beheshti University, Tehran 1983969411, Iran

2 Associate Professor, Department of Water Resources Engineering, Faculty of Civil, Water and Environmental Engineering, Shahid Beheshti University, Head of Hydraulic Committee, Iranian National Committee on Large Dams (IRCOLD)

3 Iranian Space Research Center, Tehran, Iran

Abstract

This study investigates the influence of Digital Elevation Model (DEM) accuracy and mesh resolution on flood inundation modeling using a two-dimensional (2D) hydraulic approach. The assessment of mesh independence and DEM sensitivity was carried out by examining key parameters, including computational time, extent of inundated area, maximum water depth, and average flow velocity across the floodplain domain. The findings indicate that enhancing DEM resolution not only improves the spatial accuracy of topographic representation but also contributes to reduced computational time through optimized mesh generation, fewer numerical corrections, and greater numerical stability. Conversely, while a reduction in mesh size leads to more detailed hydraulic results and improved accuracy in representing flow patterns, it simultaneously imposes a substantial increase in computation time. A mesh size of 25 meters was identified as an effective compromise between numerical precision and computational efficiency. Overall, selecting an appropriate combination of DEM resolution and mesh size plays a crucial role in ensuring both the reliability and practicality of flood inundation simulations.

Keywords

References

Ahmad, R., Abdul Maulud, K. N., Bin Zamir, U., Mohd Razali, S. F., Yaseen, Z. M., Pradhan, B., ... & Eshquvvatov, B. (2025). A systematic literature review of digital elevation models and hydrological models’ integration for advanced flood risk management. Geomatics, Natural Hazards and Risk, 16(1), 2549487.
Ahn, J., Na, Y., & Park, S. W. (2019). Development of a two-dimensional inundation modelling process using the MIKE21 model. KSCE Journal of Civil Engineering, 23, 3968-3977.
Ansarifard, S., Eyvazi, M., Kalantari, M., Mohseni, B., Ghorbanifard, M., Moghaddam, H. J., & Nouri, M. (2024). Simulation of floods under the influence of effective factors in hydraulic and hydrological models using HEC-RAS and MIKE 21. Discover Water, 4(1), 92.
Aristizabal, F., Chegini, T., Petrochenkov, G., Salas, F., & Judge, J. (2024). Effects of high-quality elevation data and explanatory variables on the accuracy of flood inundation mapping via Height Above Nearest Drainage. Hydrology and Earth System Sciences, 28(6), 1287-1315.
Bentivoglio, R., Isufi, E., Jonkman, S. N., & Taormina, R. (2022). Deep learning methods for flood mapping: a review of existing applications and future research directions. Hydrology and Earth System Sciences Discussions, 2022, 1-50.
.DHI. MIKE 21 & MIKE 3 Flow Model FM— hydrodynamic and transport module reference manual. Hørsholm, Denmark: Danish Hydraulic Institute; (2017).
Hong, V., Ly, S., Heng, S., & Lun, S. (2016). Application of the MIKE FLOOD Model to simulate an inundation map in Phnom Penh. In Proceedings of the Second Seminar Urban Water Resource Management (JSPS Core-to-Core Program), Tokyo, Japan.
.Patro, S., Chatterjee, C., Mohanty, S., Singh, R., & Raghuwanshi, N. S. (2009). Flood inundation modeling using MIKE FLOOD and remote sensing data. Journal of the Indian Society of Remote Sensing, 37, 107-118.
Shrestha, A., Bhattacharjee, L., Baral, S., Thakur, B., Joshi, N., Kalra, A., & Gupta, R. (2020, May). Understanding the suitability of MIKE 21 and HEC-RAS for 2D floodplain modeling. In World Environmental and Water Resources Congress 2020 (pp. 237-253). Reston, VA: American Society of Civil Engineers.
Tuan, L. A., Van, C. T., Binh, D. V., Kantoush, S. A., Sumi, T., Quyen, L. V., & Huong, T. T. (2024). Flood modeling in the Ba River basin using a coupled hydrodynamic model—MIKE FLOOD. River, 3(2), 199-207.
Xu, K., Fang, J., Fang, Y., Sun, Q., Wu, C., & Liu, M. (2021). The importance of digital elevation model selection in flood simulation and a proposed method to reduce DEM errors: a case study in Shanghai. International Journal of Disaster Risk Science, 12(6), 890-902.
Zheng, K., Lin, P., & Yin, Z. (2024). SHIFT: A DEM-Based Spatial Heterogeneity Improved Mapping of Global Geomorphic Floodplains. Earth System Science Data Discussions, 2024, 1-29.
Interdisciplinary Journal of Civil Engineering
Volume 1, Issue 3 - Serial Number 3
September 2025
Pages 207-219

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