Testing indirect methods to infer hydraulic conductivity in streambed sediments: preliminary results

Hydraulic conductivity, grain-size parameters, empirical approach, Kozeny-Carman model

ANALYSIS OF SPATIO-TEMPORAL DYNAMICS OF AEOLIAN PROCESSES IN ARID AND SEMI-ARID AREAS USING REMOTE SENSING

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Modellistica geologica e idrogeologica tridimensionale per la valutazione quali-quantitativa delle risorse idriche sotterranee

Management of groundwater systems requires efficient modeling tools to evaluate the available resources and to define the water balance. The value of these instruments depends on the accuracy of geological and hydrogeological conceptual model. As part of a research project aimed at assessing Groundwater Resources in strategic aquifers of Sardinia, it was tested 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 is to provide a tool to support the decision-making process in water resources management and assessment, 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 help us to create the bottom surface of the alluvial aquifer. The third phase, currently being implemented, involves the construction of a hydrogeological 3D model and the estimation of the volume of the aquifer

A methodological approach for the identification of sulphate sources in the Portoscuso area (south-western Sardinia)

Several detrimental effects due to intense industrial activities affect the groundwater of the Portoscuso area (SW Sardinia, Italy) such that the Italian Government has designed the whole territory as a contaminated site of national interest (D.M., March 12, 2003). Groundwater pollution is a crucial environmental issue in this area, where a volcanic ignimbrite succession up to 500 m thick outcrops, locally covered by sand deposits of variable thickness. Groundwater upgradient to the industrial district shows sulphate concentrations exceeding the background value of 450 mg/L calculated for the area (Vecchio et al., 2011). In order to verify the origin of sulphate, multidisciplinary investigations were carried out on the geochemical features and stable isotope ratios in groundwater

An interdisciplinary methodology to design integrated and innovative MAR systems in arid and semi-arid regions. Two case studies in Algeria and in Tunisia

Drought,  desertification, Managed Aquifer Recharge (MAR), Tunisia, Algeri

Land Cover Change Modeler: indicatori di trasformazione del territorio come driver per il monitoraggio della salinizzazione in un settore dell’Algeria

Questo studio ha come obiettivo la valutazione del trend spaziale di cambiamento della copertura e uso del suolo in un’area arida e semiarida del Nord Africa, nonché il potenziale di transizione da una classe di copertura del suolo ad un’altra considerando vari indicatori ambientali, culturali e socio-economici. Tali indicatori possono costituire i drivers per la costruzione degli scenari di evoluzione spaziale e temporale della salinizzazione dei suoli nel territorio dell’Oued Biskra in Algeria. Lo studio presentato fa parte delle attività del progetto dimostrativo WADIS-MAR, finanziato dalla Commissione Europea attraverso il Sustainable Water Integrated Management (SWIM) Programme (http://www.wadismar.eu). Partendo dalle mappe di land cover (LC) e salinizzazione elaborate da dati satellitari Landsat, sono stati testati alcuni algoritmi dedicati al Land Change Modeler (LCM). Lo studio si basa su un’analisi multitemporale di dati Landsat che ha portato allo sviluppo di un classificatore di tipo Decision Tree dedicato al riconoscimento delle aree salinizzate in ambiente arido e semiarido (Melis et al., 2013; Afrasinei et al., 2015). Questo classificatore è stato testato in particolare nel settore dell’Oued Biskra (Algeria orientale) lungo il limite settentrionale del sistema morfologico sahariano. La metodologia adottata propone di utilizzare queste mappe come base per la predizione degli scenari di evoluzione del fenomeno della salinizzazione. Tale fenomeno appare fortemente controllato dalle dinamiche sociali ed economiche legate all’utilizzo intensivo del territorio per l’agricoltura e in particolare per le coltivazioni di palme da dattero. Inoltre in questi ambienti il clima e le condizioni biofisiche locali hanno un’influenza immediata sulle variazioni di land cover anche con impatto giornaliero, pertanto questo tipo di driver, estremamente variabile, deve essere considerato nella sua dinamicità in modo differente rispetto ai parametri stabili nel tempo quali la morfologia e la litologia e rispetto a quelli a variabilità media come quelli socio-culturali ed economici

Approccio multi-scala per la definizione delle caratteristiche idrogeologiche degli acquiferi fessurati

This works aims at applying a methodology to characterize the fracture network in granitic rocks in a pilot area on the South of Sardinia. The fracture network has been characterized through a multiscale approach using digital photogrammetry and field measurements of fracture parameters. The digital photogrammetry allowed to generate a digital elevation model (DEM) of high resolution (5m), orthophotos and then the digitalization of over 900 lineaments. The orientation and the length were calculated for the lineaments. The fractures field survey provided complementary information regarding to the orientation, the aperture, the spacing and the roughness of the fractures

A Methodological Approach For The Effective Infiltration Assessment In A Coastal Groundwater

Accurate estimates of spatial and temporal distribution of groundwater recharge are of utmost importance to protect groundwater systems. In coastal areas, the fragility of the systems makes such estimates critical for the correct management and protection of water resources from saltwater intrusion. The Muravera coastal plain, in the south-eastern Sardinia, has been studied since 1960, due to important saltwater intrusion phenomena. Since the early fifties, the natural hydrodynamic equilibrium between groundwater, surface-water and seawater has been deeply modified by the construction of four dams across the Flumendosa river and the development of agriculture, tourism and aquaculture activities along the coast. To implement an integrated and sustainable management system addressed to slow down the process of saltwater intrusion and, on the other, satisfy human requirements, it is important to develop a flexible scenario analysis system that considers changes of land-use and inputs to the hydrogeological system, also in relation to climate change. In this study, the innovative Soil Water Balance code (SWB) has been applied to the Muravera plain groundwater body to calculate spatial and temporal variations of groundwater recharge. The code calculates the recharge (R) by using geographic system (GIS) data layers in combination with tabular climatological data. It is based on a modified Thornthwaite - Mather soil water balance approach, with components of the soil water balance calculated at a daily time-step. A combined experimental approach of hydrogeological, satellite remote sensing and pedological methodologies has been applied to derive data layers describing local features of: (1) land-use classification, (2) hydrologic soil group, (3) flow direction, and (4) soil-water capacity. The code has proved to be promising for the effective infiltration assessment and it can be easily updated with high resolution data acquired in the field and from satellite images