Evaluating the impact of model complexity on flood wave propagation and inundation extent with a hydrologic-hydrodynamic model coupling framework

Jannis M. Hoch*, Dirk Eilander, Hiroaki Ikeuchi, Fedor Baart, Hessel C. Winsemius

*Corresponding author for this work

Research output: Contribution to JournalArticleAcademicpeer-review


Fluvial flood events are a major threat to people and infrastructure. Typically, flood hazard is driven by hydrologic or river routing and floodplain flow processes. Since they are often simulated by different models, coupling these models may be a viable way to increase the integration of different physical drivers of simulated inundation estimates. To facilitate coupling different models and integrating across flood hazard processes, we here present GLOFRIM 2.0, a globally applicable framework for integrated hydrologic-hydrodynamic modelling. We then tested the hypothesis that smart model coupling can advance inundation modelling in the Amazon and Ganges basins. By means of GLOFRIM, we coupled the global hydrologic model PCR-GLOBWB with the hydrodynamic models CaMa-Flood and LISFLOOD-FP. Results show that replacing the kinematic wave approximation of the hydrologic model with the local inertia equation of CaMa-Flood greatly enhances accuracy of peak discharge simulations as expressed by an increase in the Nash-Sutcliffe efficiency (NSE) from 0.48 to 0.71. Flood maps obtained with LISFLOOD-FP improved representation of observed flood extent (critical success index C = 0:46), compared to downscaled products of PCR-GLOBWB and CaMa-Flood (C = 0:30 and C = 0:25, respectively). Results confirm that model coupling can indeed be a viable way forward towards more integrated flood simulations. However, results also suggest that the accuracy of coupled models still largely depends on the model forcing. Hence, further efforts must be undertaken to improve the magnitude and timing of simulated runoff. In addition, flood risk is, particularly in delta areas, driven by coastal processes. A more holistic representation of flood processes in delta areas, for example by incorporating a tide and surge model, must therefore be a next development step of GLOFRIM, making even more physically robust estimates possible for adequate flood risk management practices.

Original languageEnglish
Pages (from-to)1723-1735
Number of pages13
JournalNatural Hazards and Earth System Sciences
Issue number8
Publication statusPublished - 12 Aug 2019


Climate-KIC programme under project title “Global high-resolution database of current and future river flood hazard to support planning, adaption and re-insurance”. Dirk Eilander received funding from NWO VIDI (grant no. 016.161.324). Hiroaki Ikeuchi was financially supported by Japan Society for the Promotion of Science (JSPS) KAKENHI (grant no. JP16J07523.) Review statement. This paper was edited by Albert J. Kettner and reviewed by Guy J.-P. Schumann and one anonymous referee.

FundersFunder number
BangladeshWater Development Board
Institute ofWater Modeling
Rens van Beek and Edwin Sutanudjaja
EIT Climate-KIC
European Institute of Innovation and Technology
Japan Society for the Promotion of ScienceJP16J07523
Nederlandse Organisatie voor Wetenschappelijk Onderzoek016.161.324


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