Nationwide groundwater recharge evaluation for a sustainable water withdrawal over Italy

Study region: Italy Study focus: Groundwater recharge (GR) is the amount of water that infiltrates into the soil recharging aquifers. For Italy, we applied a water balance method for estimating GR, along with other balance components, using gratis/libre open access data and open source software. The results were compared with the data available from the literature on Central Italy, to validate the model and to investigate the variation in the GR, while considering different lithologies. The comparison of the GR results with anthropogenic water withdrawals enabled the evaluation of sustainable water use in Italy. The proposed approach can provide quantitative data in line with the Goal 6 (Targets 6.4 and 6.5) of the 2030 Agenda for Sustainable Development of United Nations (https://sdgs.un.org). New hydrological insights for the region: In Italy, the annual averaged GR is ~110 × 109 m3. This estimate may vary for specific years; in 1992 and 2015, the GR exceeded the value by 3% and 27%, respectively. According to these and related estimations, the 1981-2010 average groundwater withdrawals for civil, industrial and agricultural use were estimated to be ~14% of the averaged GR for the same period. In 1992, the withdrawals for the mineral water industry was about 0.01% of the GR and that for civil use was ~10% in 2015. In this study, we observed significant differences in the GR at the regional level, mostly influenced by the precipitation distribution and elevation.