Risk Assessment of Aquifer Salinization in a Large-Scale Coastal Irrigation Scheme, Italy

This paper describes a study conducted on a coastal agricultural area of southern Italy to assess the impending risk of aquifer degradation related to intensive groundwater pumping by farmers with the aim of offsetting the poor irrigation delivery service provided by the local water management agency. The study area is intensively farmed by small land-holding growers with high-value horticultural crops, and whose irrigation deliveries are supplied by a gravity-fed water distribution system operated by a local water users' organization. The soil and aquifer degradation hazards were appraised using a simplified environmental risk assessment procedure that allowed identifying the risk-generating processes, assessing the magnitude of impacts, and estimating the overall risks significance. The investigations revealed significant aquifer salinity increase during the past years. The stakeholders' perspective on agricultural water use was collected through field interviews, and framed using a fuzzy cognitive map, which revealed the farmers' propensity to pump groundwater rather than rely on rotational deliveries from the surface distribution system. Finally, some preliminary risk mitigation options were appraised by exploring the growers' response to possible changes of irrigation deliveries by the water users organization. The presented study consisted of multi-annual observations, data analysis, and modelling efforts, which jointly proved to be useful for analysing the main drivers to stakeholders' decisions, and their long-term impacts on water resources use and management.