Gabriele Uras

Numerical Flow and Transport Models for Simulating Current and Predicted Nitrate Contamination in Groundwater in the Bonifica Di Arborea Area (W. Sardinia, Italy)

In Italy the protection of groundwater against the deterioration of both quality and quantity is one of the top priorities of water policy and this is reflected in the substantial regulatory developments. The assessment of groundwater vulnerability to contamination is required to be conducted in accordance with environmental regulations, the most significant at the national level being Legislative Decrees 152/2006 and 30/2009, which concern a variety of environmental issues. One common form of pollution of both surface and groundwater that has been afflicting industrialised countries for decades, is nitrate contamination. This is also a major issue in Sardinia where, by means of the Water Protection Plan (PTA) it has been possible to delineate potential Nitrate Vulnerable Zones (ZVN) at the regional scale. Pursuant to the Regional Government resolution No. 1/12 of 18/01/2005, the Bonifica di Arborea, where intensive agriculture and dairy farming form the mainstays of the local economy, has been designated as a ZVN. Numerical flow and transport models have been employed to simulate groundwater conditions for assessing current nitrate contamination of the shallow aquifer. Using the calibrated and validated numerical model, it was also possible to simulate future scenarios, essential for drawing up plans for effective interventions.

Artificial Neural Networks and Kriging Method for Slope Geomechanical Characterization

In this work, Multi Layer Perceptron Artificial Neural Networks (MLP ANNs) and Kriging method are applied for slope stability analysis. Both methods have been applied in order to evaluate detrital layer depth within a test site located in countryside of Capoterra (South Sardinia, Italy). Test site consists in a large area subjected to flooding and great magnitude debris flow events. Identified area stability and strength have been analysed by building a local geodatabase that allowed to perform a correlation analysis between depth of the detrital layers and respective geotechnical, geo-mechanical, hydraulic characteristics. Some other features regarding morphological, geological, structural, physiographic and vegetation settings have been considered. The comparison between the results obtained with the MLP ANNs and kriging method shows that the two methods can be applied to implement a realistic and accurate representation of the depth and geomechanical properties of incoherent deposits.

Seawater intrusion and coastal groundwater resources management: examples from two Mediterranean regions: Catalonia and Sardinia

Seawater intrusion is a natural phenomenon that allows the encroachment of saline water into aquifers. Nevertheless, many human actions along the coastline, in particular groundwater withdrawal, enhance this process and finally cause the salinization of groundwater resources. Here we review the hydrogeological basis of seawater intrusion and describe specific cases in Catalonia and Sardinia, as examples of environmental problems and water management actions. We emphasize the origin of salinization and the hydrogeological details of each case, as well as the solutions that have been implemented to prevent groundwater salinization. [Contrib Sci 10:171-184 (2014)]

Application of three different methods to evaluate the nitrate pollution of groundwater in the Arborea plain (Sardinia – Italy)

This paper describes three different methods used to evaluate the nitrate contamination from agricultural practices in a study area located in the Nitrate Vulnerable Zone (NVZ) of the Arborea plain (Sardinia - Italy). Potential risk of contamination and concentration of nitrate pollution in groundwater has been estimated by using Parametric, Numerical and Artificial Neural Networks methods. Parametric methods consider the combination of intrinsic aquifer vulnerability to contamination index (SINTACS) and agricultural nitrates hazard index (IPNOA). The transport numerical model is based on flow model, obtained with modular three dimensional finite difference groundwater flow model (MODFLOW), and it is made applying 3-D Multi-Species Transport Model (MT3D). Artificial Neural Networks (ANNs) are used for the estimation of the nitrate concentration in monitoring well.

Local Freshwater Appropriation Assessment in a wood-energy supply chain in Sardinia

In the present work, the assessment of the freshwater appropriation for the future energy production by using forest residues will be discussed. Reference has been made to the methodology known as Water Footprint Assessment. The main objectives are related to the analysis of the appropriation of freshwater, by dividing the water volumes related to each component of an hypothetical small supply chain and by separating both the internal and external shares, with respect to the preset boundaries. Those ones are the limits of the Monte Olia public forest, which is located in the Northern side of Sardinia Island (Italy). This assessment of the freshwater appropriation is a valid tool in the wood-energy supply chain design, in the view of a more sustainable local water management.