A Modelling Approach for Assessing the Hydrogeological Equilibrium of the Karst, Coastal Aquifer of the Salento Peninsula (Southeastern Italy): Evaluating the Effects of a MAR Facility for Wastewater Reuse

Abstract

The Salento Peninsula is characterized by poor surface water resources, due to the karstic nature of its territory. On the other hand, important groundwater resources are located in the deep, karst, coastal aquifer, which is of strategic importance for the economic and social development of the area. The increasing water demand, however, if not properly managed may pose serious problems to the hydrogeological equilibrium of this aquifer, which is highly susceptible to natural and anthropogenic changes and to saltwater intrusion. Taking steps from the previous works, the present paper focuses on the characterization of the deep aquifer of the Adriatic portion of the Salento Peninsula from a quantitative point of view by means of modelling tools for the simulation of groundwater dynamics. Conclusions about the extent of the saltwater intrusion phenomenon are consequently inferred. As a result of the implementation of a density-dependent flow model, the lateral extent of such phenomenon and the vertical depth of the transition zone between freshwater and saltwater were inferred, highlighting also the role of major faults which characterize the hydraulic behaviour of the karst system under exam. The model was also applied to design a Managed Aquifer Recharge facility for management and protection of the hydrogeological equilibrium of the deep aquifer. Its positive effects on the advancement of the saline front were highlighted. Model results also allowed identifying areas where the lack of data prevents a proper comprehension of the hydrogeological processes investigated, thus representing a supporting tool for planning further monitoring campaigns.

Water Quality Assessment: A Quali-Quantitative Method for Evaluation of Environmental Pressures Potentially Impacting on Groundwater, Developed under the M.I.N.O.Re. Project

“…Due to its karstic nature, the Salento Peninsula is characterized by scarce availability of surface water resources. On the other hand, important volumes of groundwater are hosted in the deep karst aquifer, which represents a strategic resource for the socioeconomic aspects of this Mediterranean region [28,35]; it is very important to emphasize that karstic aquifers and environments are highly vulnerable to anthropogenic contamination.…”

Application of short time series analysis for the hydrodynamic characterization of a coastal karst aquifer: the Salento aquifer (Southern Italy)

“…The geological basement of the Salento Peninsula, which crops out in extensive areas, comprises layers and banks of fractured and karstified limestone and dolomitic limestone of Cretaceous age; sand, silty or sandy clay, and calcarenite of Miocene to Pleistocene age cover the basement (Ciaranfi et al 1988). The system is multi-layered comprising seven litho-stratigraphic units (De Filippis et al 2019), which are spatially distributed in different thicknesses and order. Tectonics involved a combination of gentle folds, E-W dextral and sinistral strike-slip faults, and NW-SE sub-vertical normal faults that dislocated the basement forming Horst and Graben structures.…”

“…As there is also a lack of freshwater springs and extra-regional water resources, Salento relies on groundwater as the only source of supply for drinking, irrigation, and industrial purposes. Groundwater over-exploitation started in the 1960s, consequent to the demographical and economic development, thus causing a relentless groundwater quantity reduction and quality deterioration (Cotecchia et al 2005;Polemio 2005;De Filippis et al 2019;Alfio et al 2020;Di Nunno & Granata 2020). Because of the current exploitation regime and the projected climate change induced impacts, knowledge of the hydrodynamic response of the aquifer to precipitation is a crucial aspect for present and future water management.…”

Studies on water resources salinization along the Italian coast: 30 years of work

“…An interesting study on farmed coastal plains at risk of salinization proposes changes of irrigation deliveries by the water users' organization to counter farmers' propensity to pump GW, rather than rely on rotational deliveries (Zaccaria et al 2016). For fractured aquifers, the identification of critical threshold for GW exploitation (Cherubini et al 2011;Nocchi and Salleolini, 2013) and the definition of effective MAR strategies (Polemio and Zuffianò 2020;De Filippis et al 2019) has been proposed.…”