1,720,998 research outputs found
New geophysical knowledge of groundwater systems in Venice estuarine environment
No full textUnconfined aquifers beneath the south sector of the Venice Lagoon are characterized by the presence of saline water. The results of this study allow the determination of the superficial extension of the salt water contamination in the direction of the mainland and the relationship between chemical analysis and conductivity, which reveals a complex lateral and vertical variability in both the permeability and textural pattern. Moreover, geophysical data validated by log data together with other physical and chemical results show a dislocation of the aquifer basement. This fact allows for the presumption that the salt groundwater distribution is affected by a regional tectonic lineament which extends towards the SE. Therefore salt contamination may be due to saline intrusion from the sea and the lagoon, and also from fossil brines mobilised by the combined action of tectonics and infiltration of fresh groundwater
Contaminazione salina nei sistemi acquiferi dell'entroterra meridionale della laguna di Venezia
No full textGroundwater flow in mountainous limestone aquifers deduced from hydrochemical and isotopic data (Orobic Alps, Italy)
No full textDetecting the origin of salt water contamination in groundwater in a lagoon area by the combined use of geophysical and geochemical tools: the example of the southern Venice Lagoon mainland
No full textThe south sector of the Venice Lagoon mainland is a territory characterized by the presence of saline contamination.
Sea water contamination is registered in groundwater near the coastline, and tidally dispersed sea water is usually found in the riverbeds, suspended above the surrounding land. Geophysical research, confirmed by some deep drillings, detected throughout the territory the existence of a deep salt-water aquifer storing fossil saline water at a depth of about 450 m. This research aimed to verify whether the deep fossil saline water could contribute to the salt contamination of the lagoonal mainland. Therefore, together with a critical revision of old geophysical data (vertical electric sounding -VES-, acquired during the 1970s), new geophysical sounding and geochemical analysis were performed. The revision of the geophysical data shows the presence of a dislocation of the aquifer basement: a deep buried tectonic lineament seems to affect the salt-groundwater distribution, apart from the lateral and vertical variability of permeability and the textural pattern of the stratigraphic succession. Moreover, the geochemical-isotopic analyses show the presence of fossil water in the unconfined aquifer. Therefore, salt contamination may be due to saline ingression from the sea and the lagoon, and also by the mobilization of fossil brines by means of a combined action of tectonics and fresh water dilution processes. The aim of this study is to understand the real origin of saltwater by means of chemical and isotopic analysis of water samples collected all over the area, determining the groundwater age and chemical composition and therefore, distinguishing old fossil waters from actual marine water
Influence of precipitation and deep saline groundwater on the hydrological systems of Mediterranean coastal plains: a general overview.
No full textThe increasing water demand is a concern affecting many regions in the Mediterranean Basin. To over-\ud
come this situation rim countries resorted during the last decades to a massive mobilization of their water resources,\ud
often resulting in excessive water exploitation. In such a context, understanding the effects of present recharge and\ud
aquifer salinization is crucial for correct water management. Understanding the present hydrogeological situation\ud
of coastal plains requires the knowledge of both their past morphologic conditions and their recent geological\ud
evolution. Within this framework, this paper presents a review of water related problems in the Mediterranean\ud
Basin. It suggests a conceptual model for groundwater resources in Mediterranean coastal plains, deriving from\ud
the present and past recharge processes. Special attention is paid to providing a better understanding of climate\ud
change impacts on water quantity and quality, and conservation of ecological diversit
Contributo alla Idrogeologia dell'Italia centrale: analisi dei metodi di ricerca
No full textIn the last two decades hydrogeological know-ledge in Central Italy improved significantly due to many Contributors and to different research approaches. The most significant contributions as well as the most important results are considered. In 1970 regional hydrogeology of Central Italy was still unexplored and methods of investigation suitable to that area had not yet been successfully esperimented. As basic knowledge of the regional hydrogeology was however a preliminary condition to more detailed investigations. A first attempt of hydrogeological interpretation mainly based on surface hydrogeological evidences gave poor results while comparaison between hydrology and regional geology gave better results. These results took the form of an elementary hydrogeological scheme where the main aquifers and their limits were identified. Between 1975 and 1985 the original scheme was developed in a series of more detailed hydrogeological models based on new hydrochemical and isotope investigations and on the analysis of hydrogeological balances. Quantity and quality of ground water resources have been evaluated. During the period 1970-1985 new methods of investigation suitable to the hydrology of Central Italy have been successfully experimented. Researches are presently focused on preparing more reliable hydrodynamic models based on the analysis of discharge regimes, on hydrochemistry and isotope hydrology. First attemps in this field showed that radiometric age of ground water must be compatible with the evaluated by means of hydrodynamic madels. Separate use of the two methods can lead to unreliable results. The reconnaissance phase in hydrogeological researches has been completed. A new stage of quantitative hydrogeology is under way; its goal is to study every single aquifer considered as a part of a more complex regional system
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