Goderniaux, P., Brouyere, S., Fowler, H.J., Blenkinsop, S., Therrien, R., Orban, P., Dassargues, A. 2011. How can large scale integrated surface - subsurface hydrological model be used to evaluate long term climate change impact on groundwater reserves. Managing Groundwater and the Environment (Proc. of ModelCARE 2009, Wuhan, China, September 2009). IAHS Publ. 341, p115-120.

Abstract

Estimating the impacts of climate change on groundwater represents one of the most difficult challenges faced by water resources specialists. One difficulty is that simplifying the representation of the hydrological system often leads to discrepancies in projections. This study provides an improved methodology for the estimation of the impacts of climate change on groundwater reserves, where a physically-based surface–subsurface flow model is combined with advanced climate change scenarios for the Geer basin (465 km2), Belgium. Integrated surface–subsurface flow is simulated with the finite element model HydroGeoSphere. The simultaneous solution of surface and subsurface flow equations in HydroGeoSphere, as well as the internal calculation of actual evapotranspiration, improve the representation of interdependent processes like recharge, which is crucial in the context of climate change. Climate change simulations were obtained from six regional climate model (RCM) scenarios downscaled using a quantile mapping bias-correction technique that, rather than applying a correction only to the mean, also applies a change in the distribution of wet and dry days. For the climatic scenarios considered, the integrated flow simulations show that significant decreases are expected in the groundwater levels and in the surface water flow rates by 2080.