Servizio Comunitario di Informazione in materia di Ricerca e Sviluppo - CORDIS

Evaluation of the effects of climatic variations on the recharge of aquifers in southern European catchments

An evaluation was made of the feasibility of using simulation models to predict possible modifications of the recharge of groundwater aquifers induced by climate change. This was achieved through a combined approach using informations obtained from general circulation models (GCM) with both field measurements and simulation at different scales together with a critical evaluation of the data assimilation techniques used in the models. A method of spatial disaggregation of GCM outputs was proposed and is directly usable in hydrologic models. It is illustrated with the development of local weather generators to simulate a doubling of carbon dioxide scenario on rainfall pattern and on potential evapotranspiration (PET). This information was then used, through coupling with a physically based hydrological model, to estimate the effects of climatic changes upon groundwater recharge and soil moisture in the root zone and their expected impacts on agricultural activities. At the local scale, a reference deterministic model has been used to simulate locally the water balance in the soil-plant-aquifer continuum on pluriannual series of measurements, and then, once the model validated, to predict the effect of doubling of carbon dioxide. In parallel with the local analysis, a continuous, distributed parameter model, coupled with a geographical information system, was also developed to simulate runoff, infiltration, and aquifer recharge. It was then used in a predictive mode with weather generators derived from GCMs outputs. As a result of this programme, it is clear that a doubling of carbon dioxide may probably result in slight modification in rainfall, with a general tendency to higher values in winter and spring, but in large increase of potential evapotranspiration during the summer. Excepting some specific situations, this situation will be probably responsible for a deplenishment of aquifer resources due to a combination between a marked decrease of drainage from the soil, and a higher rate of pumping in response to increasing irrigation needs.

Reported by

Université Joseph Fourier-Grenoble 1
38041 Grenoble
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