The effect of climate change on groundwater resources availability: a case study in the city of Brescia, northern Italy

The impact of climate change on water availability is alarming, both globally and locally. The city of Brescia has a large reserve of water deriving from the aquifer, the presence of springs and numerous streams, for a water supply system serving 200,000 inhabitants. The aim of this study was to project Brescia's spring discharge for two future periods 2040-2060 and 2080-2100. Observed climate components of precipitation and temperature for 20 years 2000-2020 with future data from regional climate model RCM runs on CORDEX database for three Representative Concentration Pathway RCP (RCP2.6, RCP4.5, RCP8.5) were analyzed. The future scenarios show an increment of temperature with an increment of winter's precipitation and a decrement for summer's precipitation. This future change in climate components will impact the water balance that impacts the runoff, evapotranspiration, and groundwater recharge. The two main springs of the city of Brescia are Mompiano and Cogozzo used to supply 50% of the water demand of the city in the past while it is occupied about 14% now. This drop was due to the growth of water needs, urbanization that affects the groundwater recharge and climate change. In the future, based on the study carried out, the results show a few impacts on water discharge from Mompiano and Cogozzo springs for the two periods and its clearer under RCP4.5 for period 2040-2060 that shows a decrease of about 7.8% and 3.94% respectively. This shows the importance of having a proper water resources management system to satisfy the water demand.