This chapter discusses the effects of climate change on groundwater recharge of the upper Tiber River basin (UTRB) in central Italy. The chapter also provides summaries and overview of climate change studies over the Italian territory. A calibrated and validated watershed model, soil and water assessment tool (SWAT), was forced by the climate model outputs obtained from three dynamically downscaled regional climate models (RCMs) to evaluate the recharge characteristics of the basin. During calibration, the watershed model was highly sensitivity to groundwater flow parameters. The climate change analysis from the three RCMs indicated that by the end of twenty-first century, rainfall will decrease up to 40 % in the dry period and there will be an increase in temperature that could reach as high as 3-5°C. Moreover, the bias-corrected RCM outputs showed different results among models. Such variation of result calls for further investigation of model uncertainty. Groundwater recharge shows a decreasing trend as a response to changes in rainfall. However, as the timing of both precipitation and recharge is critical for future groundwater development in the basin, further analysis through different climate models, downscaling approach and groundwater modeling needs to be taken into account.
