HGS RESEARCH HIGHLIGHT – A hybrid approach for integrated surface and subsurface hydrologic simulation of baseflow with Iterative Ensemble Smoother
Delottier, H., Therrien, R., Young, N.L. & Paradis, D. (2022). A hybrid approach for integrated surface and subsurface hydrologic simulation of baseflow with Iterative Ensemble Smoother. In Journal of Hydrology (Vol. 606, p. 127406). https://doi.org/10.1016/j.jhydrol.2021.127406
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This week we’re highlighting the results of a collaboration between Université Laval and the Ministère de l’Environnement et de la Lutte contre les changements climatiques (MELCC). This work was part of the post-doc project of Hugo Delottier along with Aquanty co-founder Rene Therrien.
This paper introduces the development of an integrated model for the South Québec region where low-flow processes are of primary concern. In this publication, HydroGeoSphere is used with a surface water mass balance module in order to reduce computational cost, enabling the use of mathematically rigorous, ensemble-based methods to support a calibration-constrained predictive uncertainty analysis.
This study is one of the first instances of a non-linear predictive uncertainty analysis for a regional scale and integrated surface and subsurface hydrologic model.
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Abstract:
Integrated surface and subsurface hydrologic models are particularly well suited for the simulation of baseflow as exchange fluxes does not rely on boundary conditions. Regional scale hydrologic models are of particular interest as they can provide guidance to stakeholders toward sustainable water resources management. However, integrated hydrologic models are rarely considered at the regional scale because their computational costs usually prevent efficient model calibration and predictive uncertainty analysis. Moreover, estimation of baseflow and each water budget component usually requires additional post-processing steps. In this paper, we thus aim here to provide a hybrid approach for the application of an integrated hydrologic model at the regional scale when low-flow processes are of primary concern. A surface water mass balance module has been developed to solve the hydrological mass balance from precipitations and temperature datasets. This module calculates potential infiltration fluxes that are used as input to the integrated modeling platform HydroGeoSphere (HGS). This approach provides a computationally tractable integrated model where low-flow processes are explicitly considered, baseflows generated in an integrated fashion, and each water budget component accessible. The model is applied to a region covering 36 900 km2 in the Southeastern part of the province of Quebec, Canada.
3D HydroGeoSphere Model of the Study Area in Southern Quebec, Canada
Thanks to the computational efficiency of the approach, a rigorous mathematical parameter estimation, the Levenberg–Marquardt form of the Iterative Ensemble Smoother, can be considered to calibrate the model to baseflow of eight main rivers, snow water equivalent and evapotranspiration. An ensemble of 187 equally-probable realizations was used for history matching of observations and for the non-linear uncertainty analysis. An improved representation of baseflow can be linked to an appropriate non-linear uncertainty quantification through an efficient integrated surface and subsurface hydrologic model to support managing water resources at the regional scale.