Intercomparison of hydrological model structures and calibration approaches in climate scenario impact projections

Bert Vansteenkiste, Mohsen Tavakoli, V. Ntegeka, Florimond De Smedt, Okke Batelaan, F. Pereira, Patrick Willems

Onderzoeksoutput: Articlepeer review

58 Citaten (Scopus)


The objective of this paper is to investigate the effects of hydrological model structure and calibration on
climate change impact results in hydrology. The uncertainty in the hydrological impact results is assessed
by the relative change in runoff volumes and peak and low flow extremes from historical and future climate
conditions. The effect of the hydrological model structure is examined through the use of five
hydrological models with different spatial resolutions and process descriptions. These were applied to
a medium sized catchment in Belgium. The models vary from the lumped conceptual NAM, PDM and
VHM models over the intermediate detailed and distributed WetSpa model to the fully distributed MIKE
SHE model. The latter model accounts for the 3D groundwater processes and interacts bi-directionally
with a full hydrodynamic MIKE 11 river model. After careful and manual calibration of these models,
accounting for the accuracy of the peak and low flow extremes and runoff subflows, and the changes
in these extremes for changing rainfall conditions, the five models respond in a similar way to the climate
scenarios over Belgium. Future projections on peak flows are highly uncertain with expected increases as
well as decreases depending on the climate scenario. The projections on future low flows are more uniform;
low flows decrease (up to 60%) for all models and for all climate scenarios. However, the uncertainties
in the impact projections are high, mainly in the dry season. With respect to the model structural
uncertainty, the PDM model simulates significantly higher runoff peak flows under future wet scenarios,
which is explained by its specific model structure. For the low flow extremes, the MIKE SHE model projects
significantly lower low flows in dry scenario conditions in comparison to the other models, probably
due to its large difference in process descriptions for the groundwater component, the groundwater-river
interactions. The effect of the model calibration was tested by comparing the manual calibration
approach with automatic calibrations of the VHM model based on different objective functions. The calibration
approach did not significantly alter the model results for peak flow, but the low flow projections
were again highly influenced. Model choice as well as calibration strategy hence have a critical impact on
low flows, more than on peak flows. These results highlight the high uncertainty in low flow modelling,
especially in a climate change context.
Originele taal-2English
Pagina's (van-tot)743-755
Aantal pagina's13
TijdschriftJournal of Hydrology
StatusPublished - 2014


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