Accurate knowledge of groundwater availability and its variations is essential for sustainable groundwater management. Within this framework, the water balance serves as a valuable tool for assessing water resource availability. Currently, management authorities require more precise evaluations of groundwater resources to address the growing demand for freshwater.
In this study, the water balance was determined for the main hydrogeological structures in the Central Apennines (Italy). The calculated outflows were compared with spring discharge data sourced from existing literature. Inflow data were collected over a six-year period (2018–2023), accounting for both rainfall and snow contributions. Unlike many previous studies that focused only on liquid inflows from rainfall, this research properly evaluated snowmelt contributions using data from a recent network of snow gauges. These contributions were incorporated into total precipitation estimates to achieve more accurate results.
For each hydrogeological structure, monthly inflow datasets from rain gauges were interpolated using regression equations and subsequently applied to the water balance assessment. An initial comparison of water balances, estimated with and without snowmelt data, revealed that excluding snow contributions can lead to significant underestimations of infiltration rates. Moreover, a comparison between calculated outflows—including snowmelt—and measured spring discharges demonstrated strong agreement for each investigated hydrogeological structure.