Nutrient processes in groundwater are a well known -and widely studied- issue, often contributing to aquifer contamination in densely populated areas worldwide. Nevertheless, stakeholders now almost assume that the problem is not only present, but also difficult to resolve, despite the scientific and political efforts. Therefore, nitrate contamination is almost set aside, compared to new issues, such as emerging pollutants.
The Lombardy Plain (Italy) is an area highly affected by nitrates contamination, due to the coexistence of intense agricultural, livestock farming, industrial sites and urban sprawling, and a complex multilayer aquifer system.
Recent studies demonstrated that despite the thirty-year efforts to implement the European Nitrate Directive, groundwater nitrate contamination is still a serious threat potentially affecting up to 9,000,000 inhabitants, with most monitoring wells showing steady or increasing NO3 concentrations. Results hence shows that the adopted strategies are not effective, and that a new approach is required to solve this issue, taking into account both the complexity of the hydrogeological system and the socio-economic context that triggers nitrate contamination. For this reason, a socio-hydrogeological approach was adopted in the frame of the INTEGRON project (Cariplo Foundation, grant number 2015-0263), whose overall goal is to integrate the role of groundwater as sink or source of nutrients (N and P) in river basin mass balances. A classical hydrogeological and hydrogeochemical approach was adopted for aquifer characterization, to understand the timing of nutrient transfer from and to the surface, and to identify the main contamination sources. Groundwater modelling was used to obtain long term projection of the evolution of nutrients concentrations in the system.
In addition, tools and analyses typical of social sciences were integrated in the study. A Social Network Analysis was performed at the beginning of the investigation permitting to unveil the social structure of the studied area, and to highlight both social factors and key stakeholders that would determine the success of the implementation of the new science-based actions resulting from the hydrogeological investigation outcomes. To ensure a more comprehensive understanding of the needs and emergencies faced by local water users, public engagement activities were undertaken, targeted to both capacity building and outreach. The administration of semi-structured interviews and results dissemination fostered the creation of a network of mutual trust between farmers and the research team. Finally, all the recommendations resulting from the project were discussed in an open meeting with local stakeholders, to ensure a consensus on the proposed guidelines, thus combining bottom-up and top-down approaches for water resources management.
Prior to this investigation, socio-hydrogeology was mainly implemented in developing countries. Results of this project demonstrate the effectiveness of a such approach to support regional groundwater governance also in European contexts.