Relationship between rainfall and water table in a coastal aquifer: the case study of Castelporziano presidential estate

This study is focused on the analysis of seasonal and annual variability of water table during last 20 years of the coastal aquifer of Castelporziano Presidential Estate, a protected area of 59 Km(2) located in the periphery of Rome. A comparison with the local trends of rainfall at "Castello" gauging station at different time scales (monthly, seasonal and annual) has been carried out. The results highlight differences between the coastal area and eastern and northern sector of the Estate. Indeed, the seasonal effect due to local meteoric recharge is direct and regular during the year in the coastal area in respect to the eastern and northern sectors of the Estate. Moreover, annual steady regime and multi-year trend of groundwater levels suggest the contribution from the adjacent volcanic aquifer of Albani Hills. In the latter case, the regional groundwater flow is affected by the intense withdrawals. The maintenance of the monitoring network will allow to define the flow paths of the groundwater that characterize the coastal aquifer of Castelporziano.