Using Screening Numerical Models to Analyze Groundwater Systems: The Case Study of a Major Karst Spring Supporting a NATURA2000 Site

In this contribution, we present a preliminary phase of a project, focused on the conceptual and numerical modelling of groundwater flow in the of the carbonate structure of the Lepini Mountains, whose Western side feed the Ninfa Spring (Central Italy). In this framework, we describe a stepwise modelling procedure based on the implementation of two end-member models of the Lepini aquifer, corresponding to two antithetic conceptualizations of the system. The final target of the research will be to investigate the drivers of the observed decrease of the spring discharge, mainly groundwater withdrawals or effective recharge variation due to climate change. This understanding is essential for any future efforts to protect the spring ecosystem and to properly address the monitoring activities.