Satellite-based monitoring of groundwater utilization for irrigation: a case study in Southern Italy

In 2000, the Water Framework Directive (WFD) adopted for the first time a global approach to the risks to which EU waters are exposed, according to which the management of water resources must pay attention to land use to take into account the qualitative and quantitative aspects of water. In this context, accurate mapping of actual irrigated areas represents key information for water resource managers, both to plan sustainable use and for the prevention of unauthorized water withdrawals. Many studies have demonstrated that Earth Observation (EO) data are an effective tool for mapping irrigated areas and quantifying the irrigation water volumes at different spatial scales. This study examines an area of 39 municipalities located in the lower Volturno basin in Southern Italy. Here, integrated technologies based on the analysis of Sentinel-2 (S2) EO data, Machine Learning (ML) algorithm, and Geographic Information Systems (GIS) for the mapping of irrigated areas have been applied, outside the areas served by distribution plants of the Consortium for Land Reclamation and Irrigation of the Lower Volturno Basin (ConsBiv). By cross-referencing this geospatial information with the database of the authorized irrigation wells, the methodology for mapping the extra-consortium irrigated areas, potentially without concessions, was identified. The results highlighted areas potentially irrigated with unregistered wells, for a total area of 3,020.9 hectares. Here, the estimate of the total water volumes drawn from the aquifer reports a value of 12.39Mm³ referring to the growing season 2021.