322,878 research outputs found
Hydrogeological conceptual model of the Upper Chienti River basin aquifers (Umbria-Marche Apennines)
No full textAn updated conceptual model of groundwater flow of carbonate
fractured aquifers of Apennine basin of the Chienti River (Marche
Region) has been developed. This model derives from the application of classical hydrogeological approach, which is based on a detailed field survey, by upscaling methodology, aimed to localize the main spring locations (15 springs) and to evaluate their mean discharge (total discharge of about 3280 L/s). Acquired data have been combined with the hydrogeological evaluation of the geologicalstructural setting, for defining the hydrogeological role of the lithological complexes and of the structural setting (faults and thrusts), conditioning groundwater flow direction and amount. The geologicalstructural setting is typical of Central Apennine in the Umbria- Marchean succession. The bottom carbonate unit corresponds to the carbonate platform, overlapped by calcareous complexes having marly beds and marly-clayed complexes of pelagic facies, by a total thickness of about 2500-3000 m. Compressive tectonic processes, in a E-verging thrust-and-fold belt, combined with intense translational movements gave rise to significant overthrusts at regional scale. The cores of anticlines host large basal aquifers, hydraulically separated by low-permeability boundary due to marly and clay complexes, respect with the surrounding Scaglia aquifers. Groundwater flow moves mainly along N-S direction, parallel to the main thrusts, which act as no-flow limit. The proposed hydrogeological model includes seven local aquifers. There are two independent basal aquifers, feeding a deep groundwater flow in the basal carbonate complexes, including areas out of the hydrographic basin of Chienti River. Spring fed by these basal aquifers have a mean discharge of 1460 L/s. Additional five aquifers characterized by less deep and more local groundwater flow correspond to the Scaglia complexes, with a mean discharge of about 1820 L/s. The extension and the limits of all these aquifers have been verified by the evaluation of effective infiltration values, to define the recharge area of each spring group.
The resulting conceptual model has been independently validated by chemical and isotopic analyses of groundwater, which confirmed or require modification of the preliminary model obtained by the hydrostructural approach
Co-Occurrence of Earthquake and Climatic Events on Groundwater Budget Alteration in a Fractured Carbonate Aquifer (Sibillini Mts.—Central Italy)
No full textThe combination of several factors related both to human pressure as well as natural issues could lead to a marked alteration of the groundwater budget terms and a decrease in groundwater availability. The basal aquifer of the Sibillini Mts. is a strategic resource of drinking water in the central sector of Apennine (Italy). The seismic sequence that occurred in this area in 2016 induced transient and sustained modifications in the aquifer settings. Springs located on the western side of the Sibillini Mts. were characterized by an increased discharge, while in contrast, the eastern springs suffered an intense drop in their groundwater discharge. In 2017, a drought period started immediately after the exhaustion of the seismic sequence effect. The comparison between the recharge and discharge of the major springs in the 2000–2020 period allowed the definition of the different responses of the aquifer to the co-occurrence of earthquakes and climatic events. The hydrodynamic alteration triggered by the earthquake induced a huge depletion of the groundwater stored in the eastern sector of the basal aquifer (at least 50 × 106 m3). The scarce recharge occurring in the following drought period (more than 30% of the average annual value) was not enough to restore the groundwater resources, causing a serious drinking water supply crisis in the main tapped springs in the eastern sector of the aquifer
The role of alpine valley fill deposits for groundwater storage (Dolomites, Italy)
No full textIn the Dolomites mountain range, the most productive aquifers are found in porous valley-fill deposits, such as alluvial, glacial and other heterogeneous types of clastic sediments. These deposits store significant amounts of groundwater resources and are laterally bordered by steep carbonate reliefs, which in turn constitute fractured high-yielding aquifers. The talus cones and slopes at the base of the rock cliffs play the role of hydraulic connection between the fractured aquifers and the porous aquifers at the valley floor. This situation is very well represented in the San Lucano glacial valley system in the Dolomite Mountains (Italy), where average groundwater resources were estimated at approximately 2 m3/s. The hydrogeological data collected in this study allowed to identify the interaction between stream discharge and the saturated zone of the aquifers and to define a preliminary model of recharge and storage of the valley-fill aquifer
Fractured carbonate aquifers of Sibillini Mts. (Central Italy)
No full textThe aim of the present map is to illustrate a detailed pre-earthquake hydrogeological conceptual model of the Sibillini Mts. This area was struck by a prolonged seismic sequence of up to Mw 6.5 in 2016. Geological, tectonic, and hydrogeological data were collected from the literature before 2016, subsequently standardized and re-interpretated with the aim of presenting a hydrogeological map (1:50,000 scale) of the Sibillini Mts. carbonate system (Central Italy). The map is supported by 11 hydrogeological both cross and longitudinal sections, which show the underground spatial relationship between aquifers, aquicludes, and tectonic elements. This Map provides a model of comparison for the new hydrogeological conditions emerging from the post-seismic research
Contribution of the Roccamonfina Caldera to the basal volcanic aquifer recharge: first considerations
No full textA preliminary hydrogeological investigation of the Roccamonfina Caldera was conducted in order to increase the local knowledge of the multilayer aquifer hosted within the ignimbrite deposits. Three aquifer levels were distinguished according to stratigraphic data and according to the bottom well depth. The aquifer levels recharge punctual and linear springs with a total natural discharge of about 200 L/s. A preliminary groundwater recharge of about 300 L/s was calculated using the effective infiltration value (368 mm/y) suggested by Boni et al. (1986). A more detailed groundwater budget will be calculated afterwards, using the distributed method. Groundwater effective recharge will be calculated taking into account data about rainfall, land use, runoff and withdrawals value
Preliminary conceptual model of an Alpine carbonate aquifer (Pale di San Martino, Dolomites, Italy)
No full textA hydrogeological and hydrochemical monitoring was conducted in the Pale di San Martino mountain ridge (Trento and Belluno Provinces, Italy) to build a preliminary conceptual model of the groundwater system. The model derives from a combination of new fieldwork and preexisting data provided by various public authorities. New data include geological and hydrogeological surveys, such as in situ measurements of the physical and chemical parameters, geochemical sampling and streamflow measurements. The lithologies outcropping in the area were grouped into seven hydrogeological complexes, each playing a different role in groundwater circulation. The dolomitic body of the ridges forms the main aquifer complex and is located above a terrigenous and evaporitic aquiclude. Due to this geometrical relationship, the site can be considered an isolated hydrostructure with well-defined no-flow boundaries. The main springs outcome near the aquifer-aquiclude boundary and in particular where the elevation of the contact is low and the tectonic pattern favors the drainage. Most of them have a calciumbicarbonate water composition, low temperature and low electrical conductivity, supporting the hypothesis of a fast flowing circulation in carbonate rocks and a high-altitude recharge. Seasonal streamflow measurements allowed the identification of linear springs and provided the first cumulative discharge data at the scale of the entire mountain group. The resulting model highlights a great spatial and temporal variability of the groundwater resources. Considering the geometry of the aquifer and the great seasonal variability of the discharge, it is possible to infer the absence of significant groundwater reserves at a regional scale. Thus, the hydrostructure shows a great capacity to supply water resources (mean discharge of 6 m3/s), but a low selfregulation capacity. It is necessary to consider this aspect when planning a long-term exploitation of the water resources that are used in the area for drinking purposes and hydropower generation
Le risorse idriche sotterranee dell'alto bacino del fiume Aso (Parco Nazionale dei Monti Sibillini): Studio idrogeologico e valutazione dello stato di utilizzazione
No full textGroundwater of the Aso River, included in the National Park of Sibillini Mounts, has been evaluated and characterised by discharge, chemical and isotopic measurements.The total amountof baselow in 2009, mainly due to streambed springs is about 1800L/s, 530 of those are tapped for drinking use by tunnel drainage
Groundwater contribution in flooding events of Ostia Antica archeological site (Coastal aquifer of Rome –Italy).
No full textDiffusive author(s), cohesive author: Analysis of S/N (1994)
No full textThis study indicates the ways in which various aspects of the author(s) are brought forth in Dumb type’s performance art, the S/N production. Previous research has suggested a non-hierarchical organization of Dumb type and the absence of a “privileged author” in Dumb type’s collaborative work, S/N. However, the results that I have investigated from member’s interviews on the creative process of S/N along with my analysis of the recorded images of S/N, indicate a different aspect of the author(s). First, S/N was created through, so to speak, the collective ideas of the members of Dumb type. Further, S/N has at least nine quotations from previous performances, installations, and printed writings, besides the work-in-progress technique. Explicating one of the “author functions” as given by Michel Foucault, each text has plural subjects of the author. However, it has been revealed from members’ interviews that Teiji Furuhashi had a decision-making role in selecting the members’ ideas within the performance. Since then, S/N has had plural subjects of creation; however, Furuhashi is one of the subjects of creation along with the “privileged author.” S/N has plural authors (diffusive authors) yet at the same time, it has a “privileged author,” Teiji Furuhashi (cohesive author)
Sustained post-seismic effects on groundwater flow in fractured carbonate aquifers in Central Italy
No full textA sustained increase in spring discharges was monitored after the 2016 Central Italy seismic sequence in the fractured carbonate aquifer of Valnerina–Sibillini Mts. The groundwater surplus recorded between August 2016 and November 2017 was determined to be between 400 and 500 × 106 m3. In fractured aquifers, the post-seismic rise in spring discharges is generally attributed to an increase in bulk permeability caused by the fracture cleaning effect, which is induced by pore pressure propagation. In the studied aquifers, the large amount of additional discharge cannot only be attributed to the enhanced permeability, which was evaluated to be less than 20% after each main seismic event. A detailed analysis of the spring discharge hydrographs and of the water level at five gauging stations was carried out to determine the possible causes of this sudden increase in groundwater outflow. Taking into account the geological and structural framework, a conceptual model of a basin-in-series has been adopted to describe the complex hydrogeological setting, where the thrusts and extensional faults have clearly influenced the groundwater flow directions before and after the seismic sequence. The prevalent portion of the total post-seismic discharge surplus not explained by the increase in permeability has been attributed to changes in the hydraulic gradient that caused seismogenic fault rupture and the disruption in the upgradient sector of the aquifer. The additional flow calculated through the breach of the pre-existing hydrostructural barrier corresponds to approximately 470 × 106 m3. This value is consistent with the total discharge increase measured in the whole study area, validating the proposed conceptual model. Consequently, a shift in the piezometric divide of the hydrogeological system has been induced, causing a potentially permanent change that lowers the discharge amount of the eastern springs
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