Management of groundwater systems requires efficient modeling tools to evaluate the available resources, to define the water balance and to predict the fate of contaminant. The value of these instruments depends on the accuracy of geological and hydrogeological conceptual model. As a part of a research project aimed at assessing Groundwater Resources in strategic aquifers of Sardinia, the PhD research objective was to develop and test a methodology for quantitative and qualitative study of groundwater resources, based on the use of three-dimensional geological and hydrogeological modeling. The aim of this research was to provide a tool to support the decision-making process in water resources assessment and management, applicable in different hydrogeological settings. The pilot study area is the porous Quaternary alluvial aquifer of the Cixerri Valley. The valley, located in the South-Western Sardinia, is an East-West oriented syncline linked to the tertiary tectonics, bordered by Paleozoic metamorphic and sedimentary formations and filled by tertiary and quaternary alluvial. The methodology can be summarized in three main phases. The first involved the construction of a Geodatabase (DB), where geological and hydrogeological data (geological maps and cross sections, geophysical data, wells and borehole logs, piezometric levels, hydrogeological parameters and geochemical features) were cataloged. During the second phase a 3D geological model of the shallow Cixerri aquifer has been built. The data collected in the DB were validated and used for the construction of geological sections orthogonal and parallel to the fold axis. The interpolation of alluvial horizons of each sections helped us to create the bottom surface of the alluvial aquifer. The third phase involved the construction of a hydrogeological 3D model, the identification of the main groundwater flow directions, the development of a method to determine hydraulic permeability and the effective porosity of the aquifers trough grain size analysis, the estimation of the volume of the aquifer, the determination of water budget and the geochemical characterization of groundwater, particularly nitrate. The implemented 3D hydrogeological model will help the calibration of a coupled numerical groundwater flow and solute transport model of the Cixerri area. While highly useful for groundwater management, such models are notoriously difficult to constrain, and applying geochemical data as calibration targets is a promising and evolving area of research.

Applicazione di modelli geologici e idrogeologici 3D per la valutazione delle risorse idriche sotterranee dell’acquifero alluvionale della Piana del Cixerri (Sardegna Sud Ovest)

FENZA, PATRIZIA
2017-04-19

Abstract

Management of groundwater systems requires efficient modeling tools to evaluate the available resources, to define the water balance and to predict the fate of contaminant. The value of these instruments depends on the accuracy of geological and hydrogeological conceptual model. As a part of a research project aimed at assessing Groundwater Resources in strategic aquifers of Sardinia, the PhD research objective was to develop and test a methodology for quantitative and qualitative study of groundwater resources, based on the use of three-dimensional geological and hydrogeological modeling. The aim of this research was to provide a tool to support the decision-making process in water resources assessment and management, applicable in different hydrogeological settings. The pilot study area is the porous Quaternary alluvial aquifer of the Cixerri Valley. The valley, located in the South-Western Sardinia, is an East-West oriented syncline linked to the tertiary tectonics, bordered by Paleozoic metamorphic and sedimentary formations and filled by tertiary and quaternary alluvial. The methodology can be summarized in three main phases. The first involved the construction of a Geodatabase (DB), where geological and hydrogeological data (geological maps and cross sections, geophysical data, wells and borehole logs, piezometric levels, hydrogeological parameters and geochemical features) were cataloged. During the second phase a 3D geological model of the shallow Cixerri aquifer has been built. The data collected in the DB were validated and used for the construction of geological sections orthogonal and parallel to the fold axis. The interpolation of alluvial horizons of each sections helped us to create the bottom surface of the alluvial aquifer. The third phase involved the construction of a hydrogeological 3D model, the identification of the main groundwater flow directions, the development of a method to determine hydraulic permeability and the effective porosity of the aquifers trough grain size analysis, the estimation of the volume of the aquifer, the determination of water budget and the geochemical characterization of groundwater, particularly nitrate. The implemented 3D hydrogeological model will help the calibration of a coupled numerical groundwater flow and solute transport model of the Cixerri area. While highly useful for groundwater management, such models are notoriously difficult to constrain, and applying geochemical data as calibration targets is a promising and evolving area of research.
19-apr-2017
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11584/249608
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