Estimación de los efectos del cambio climático en la recarga de los acuíferos de la Plana de La Galera y del aluvial del Ebro en Tortosa mediante modelos hidrológicos de balance de agua

Abstract

The increasing evidence related to climate change motivates the need to evaluate its impact on groundwater resources. Here we report the evaluation of the effects of climate change on the recharge of the Plana de La Galera and the Tortosa alluvial aquifers, near the Ebre Delta. Such evaluation is based on the predictions of temperature, T, and precipitation, P, of 3 climate models for the A1B emission scenario obtained within the ENSEMBLES project for the periods of 2020-2050 and 2069-2099. The regional predictions for T and P have been downscaled at the basin scale by means of statistical regression techniques. The effects of the changes in T and P on water resources have been evaluated with a hydrological water balance model solved with VISUALBALAN. Model resuls show: 1) an increase in mean annual T; 2) a reduction of annual P with the possibility of a moderate increase in rainfall during winters; 3) an increase in arid conditions; and 4) a reduction of aquiferrecharge of up to 30% compared with recharge in the period 1960-1990. Model predictions may be unreliable due to uncertainties in the definition of the scenarios, the predictions of regional climate models, the downscaling techniques, hydrological models and the hypotheses adopted for the future use of the soil, agricultural practices and irrigation systems. Such uncertainties could be reduced by considering the predictions of the most recent climate models and by improving the dowsnscaling techniques