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We analyze the variation in groundwater budget by modeling an aquifer in a semi-arid region in southern Italy, using different good pumping scenarios. This aquifer is overexploited due to the agricultural vocation of the area. We propose an integrated method to assess the distribution of hydrogeological parameters and the recharge rates. The hydrogeological parametrization is performed through a hydrostratigraphic approach using the geostatistical tool. Recharge rates are computed through a soil water balance application, using different monitoring stations over the area for the whole period of interest. Integrating the results of this analysis with pumping scenarios based on the water irrigation requirement of the main crops in the area, different water budgets are estimated. The results show how different pumping scenarios affect the availability of water resources and thus underline the importance of management. This integrated hydrogeological model can be applied to other areas with similar hydrogeological characteristics, and it can be considered a valuable tool for evaluating sustainable groundwater management strategies, considering land use practices and socio-economic factors. [ABSTRACT FROM AUTHOR]

When dealing with groundwater resources, a better knowledge of the hydrological processes governing flow in the unsaturated zone would improve the assessment of the natural aquifer recharge and its vulnerability to contamination. In North West Europe groundwater from unconfined chalk aquifers constitutes a major water resource, therefore the need for a good hydrological understanding of the chalk unsaturated zone is essential, as it is the main control for aquifer recharge. In the North Paris Basin, much of the recharge must pass through a regional chalk bed that is composed of a porous matrix with embedded fractures. The case study regards the role of the thick unsaturated zone of the Cretaceous chalk aquifer in Picardy (North of France) that controls the hydraulic response to rainfall. In order to describe the flow rate that reaches the water table, the kinematic diffusion theory has been applied that treats the unsaturated water flow equation as a wave equation composed of diffusive and gravitational components. The kinematic diffusion model has proved to be a convenient method to study groundwater recharge processes in that it was able to provide a satisfactory fitting both for rising and falling periods of water table fluctuation. It has also proved to give an answer to the question whether unsaturated flow can be described using the theory of kinematic waves. The answer to the question depends principally on the status of soil moisture. For higher values of hydraulic Peclet number (increasing saturation), the pressure wave velocities dominate and the preferential flow paths is provided by the shallow fractures in the vadose zone. With decreasing values of hydraulic Peclet number (increasing water tension), rapid wave velocities are mostly due to the diffusion of the flow wave. Diffusive phenomena are provided by matrix and fracture-matrix interaction.

The understanding of the transport and degradation phenomena of chlorinated ethenes in fractured aquifers as well as the assessment of the cleanup times poses an extreme technical challenge. In the present study a method to analyze reactive transport and reductive dechlorination of chlorinated solvents in fractured aquifers is presented. Reductive dechlorination pathway, adsorption processes, mass exchange phenomena between mobile and stagnant zones as well as the non - linear flow behaviour in fractures are considered. The developed methodology, considering reductive dechlorination processes in a Lagrangian framework, is able to simulate the motion of particles affected by first-order network reactions, so that particles move according to their chemical state affecting physical transport processes (advection, dispersion, mass transfer exchange between mobile and stagnant zone). The developed model is applied to a case study of groundwater contamination in the industrial area of Modugno - Bari (Italy), where the limestone aquifer has a fractured and karstic nature. The steady state distribution of the contamination by chlorinated ethenes with the source at the hot spot is obtained and compared with the observed scenario of contamination in order to estimate the plausible transport and degradation processes as well as the mass loading at source. The carried out study represents and valuable tool for deciding the role of natural attenuation in a treatment where the natural attenuation capacity of groundwater can be integrated with engineering methods for site remediation. [ABSTRACT FROM AUTHOR]

Modelling fluid flow and solute transport dynamics in fractured karst aquifers is one of the most challenging tasks in hydrogeology.

The present study investigates on the hotspots of groundwater contamination in the industrial area of Modugno (Bari – Southern Italy) where the limestone aquifer has a fractured and karstic nature.

A rough walled parallel plate model coupled with a geostatistical analysis to infer the values of the equivalent aperture has been implemented and calibrated on the basis of piezometric data. Using the random walk theory, the steady state distribution of hypothetical contamination with the source at the hot spot has been carried out reproducing a pollution scenario which is compatible with the observed one. From an analysis of the flow and transport pattern it is possible to infer that the anticline affecting the Calcare di Bari formation in directions ENE-WSW influences the direction of flow as well as the propagation of the contaminant. [ABSTRACT FROM AUTHOR]