1,720,957 research outputs found
Seawater intrusion modeling in the Metaponto coastal aquifer (Basilicata, southern Italy).
No full textThe present study aims to model the seawater intrusion (SWI) in the Metaponto coastal plain (Basilicata region, southern Italy) by analysing the geological, hydrogeological, and hydrochemical features of the aquifer system and external factors such as excessive withdrawals and climate change. In the study area, groundwater supplies are crucial for agricultural and economic growth.
The Metaponto coastal plain is a relevant area for the region development due to the touristic and intensive agriculture sectors. Different anthropogenic impacts play a significant role in facilitating the SWI process in addition to the effects of climate change. In the last century, the Irrigation and Land Development Authority’s hydraulic arrangement and land reclamation works of the marshy areas have aided the development of the plain. Groundwater exploitation to support agriculture, tourism, and industrial activity, as well as the effects of climate change causing modifications in the recharge process, have strongly impacted the hydrogeological conditions of the aquifers in the whole plain, intensifying the potential SWI that must be considered relevant in this coastal system.
Nowadays, groundwater resources are exposed to quantitative degradation due to the historically unfavourable climatic conditions worsened by climate change and the growing water demand, and to qualitative degradation also caused by the SWI. The effective infiltration rate of the area is moderate due to the Mediterranean climate conditions, characterized by high temperatures and scarce precipitation concentrated mainly in winter.
Based on the outcomes of different studies conducted in the study area, such as hydrogeological and hydrochemical investigations, and the intrinsic vulnerability to SWI assessment, numerical simulations were carried out in this work for the portion of the coastal plain more susceptible to SWI. The geological, hydrogeological, hydrological, climatic, and hydrochemical data collected and processed were employed to define the aquifer conceptual model, which was the first step for the following numerical simulations of groundwater flow and the modeling of the SWI phenomenon. To evaluate and model the SWI process in the most prone area of the Metaponto coastal plain, groundwater flow and variable-density transport, under steady-state and transient conditions, were simulated with MODFLOW and SEAWAT codes integrated into Visual MODFLOW Flex 7.0 software (© 2021 by Waterloo Hydrogeologic). A three-dimensional groundwater flow numerical model was developed, and water table and groundwater salinity variations were simulated starting from the hydrogeological conceptual model of the coastal aquifer.
The pumping rates effects and the climate change impact on the aquifer recharge were considered in different scenario simulations. Considering the climate change scenario on direct recharge assessment, no significant changes to the SWI phenomenon result. On the contrary, higher groundwater pumping discharges appear to influence the inland progression of brackish water. The results highlighted that the SWI is potentially not negligible in the future under wells exploitation and may impact the groundwater SWI level risk. The numerical modeling outcomes presented in this work can support groundwater quality and quantity protection and provide indications for implementing management criteria and strategies addressing climate change and variations in water demand
Seawater intrusion modeling under climate and anthropogenic changes in the Metaponto coastal aquifer (Basilicata, Southern Italy)
Full text linkThe Metaponto coastal plain, located in the Basilicata region (southern Italy), is a relevant area for economic development due to the touristic and intensive agricultural sectors. In the 20th century, the land reclamation works, irrigation systems, and wells exploitation to support agriculture and industry strongly impacted the hydrogeological system, intensifying the potential seawater intrusion (SWI) that must be considered relevant in this coastal aquifer. The effective infiltration rate of the area is moderate due to the Mediterranean climate conditions, characterized by high temperatures and scarce precipitation concentrated mainly in winter. The present study aims to evaluate and model the SWI process in the most prone area of the Metaponto coastal plain. Groundwater flow and variable-density transport, under steady-state and transient conditions, were simulated with MODFLOW and SEAWAT codes integrated into Visual MODFLOW Flex 7.0 software. The pumping rate effects and the impact of climate change on the aquifer recharge were considered in different scenario simulations. The results highlighted that the SWI is potentially not negligible in the future under exploitation and may impact the groundwater SWI level risk. The numerical modeling outcomes presented in this work can be used for the effective management of the Metaponto coastal plain groundwater resources
Groundwater characterization focusing on the seawater intrusion risk in the Metaponto coastal plain (Basilicata, southern Italy)
No full textThis paper aims to assess and model the seawater intrusion (SWI) risk in the Metaponto coastal aquifer (Basilicata, southern Italy) by characterising its intrinsic geological and hydrogeological setting and analysing the external factors such as excessive withdrawals and climate change causing modifications in the recharge process. Groundwater resources are crucial for the economic development of intensive agricultural activities and tourism in the Metaponto plain.
It represents for the entire Basilicata region a relevant economic area for its marked agricultural vocation and the presence of residential settlements, tourist facilities, and natural areas such as woodlands and wetlands. During the 20th century, the anthropogenic impacts, mainly linked to the construction of modern irrigation systems, land reclamation works, overexploitation of wells, and the development of agricultural and industrial activities, have significantly modified the plain. Indeed, the hydrogeological system was negatively impacted by the changes in land use, threatening groundwater availability and quality along the coastal plain and magnifying the risk of aquifer pollution. These modifications also increased soil salinization and SWI risks.
Nowadays, groundwater resources are particularly exposed to quantitative degradation due to the historically unfavourable climatic conditions worsened by climate change and the growing water demand and to qualitative degradation also caused by the SWI. The previous hydrochemical investigations, which examined the distribution of dissolved ions in groundwater, showed a progressive mixing between freshwater and seawater, highlighting the areas with
higher SWI proneness. The groundwater vulnerability to SWI of the entire coastal plain was evaluated through the GALDIT method.
Furthermore, numerical simulation modeling was performed for the portion of the plain characterized by a greater propensity to SWI based on the results of hydrochemical analyses and the GALDIT method application. Once the study area was selected, the geological, hydrogeological, hydrological, climatic, and hydrochemical data were acquired to define the accurate conceptual model of the study area, which is the first step for the subsequent groundwater flow numerical simulations, and the modeling of the SWI phenomenon.
The MODFLOW and SEAWAT codes were used within the Visual MODFLOW Flex 7.0 software (© 2021 by Waterloo Hydrogeologic) to implement the input data, define the boundary conditions and carry out the numerical modeling of groundwater flow with the following variable-density transport. Groundwater flow simulations were conducted in steady-state and transient conditions. Afterward, starting from the electrical conductivity values measured on selected groundwater samples, the total dissolved solids (TDS) concentrations expressed in mg/l were derived.
Subsequently, the transient transport model was implemented. Three scenarios were simulated, considering the impact of climate change on the aquifer recharge and different pumping rates effects.
The most significant hydrogeological condition on the SWI risk is attributable to the pumping rate scenario of 100 l/s. Under this condition, the SWI risk is not negligible in the future, and it can cause negative effects on the quality of the coastal aquifer groundwater. The results highlighted that the aquifer requires reliable management strategies to prevent the SWI phenomenon progression
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Hydrogeological characterization of the San Giovanni spring (Castelluccio Inferiore, Basilicata region).
No full textThe main aim of this study is to identify strategic groundwater resources belonging to the hydrostructure of the northern sector of Lauria Mountains; in particular, the groundwater of the La Spina - Zaccana Mounts limestone-dolomite aquifer, to allocate for drinking water supply during water emergency conditions. The aquifer under study lies in the north-eastern portion of the Lauria Mountains hydrostructure, between 1652 m (La Spina Mount) and 506 m a.s.l. (San Giovanni spring), and is drained from the San Giovanni spring front; minor springs are scattered at the edges of the hydrostructure and characterized by limited shallow groundwater flow path.
The in situ geological and hydrogeological surveys, still in progress, make evident that the limestone-dolomite lithologies are characterized by intensely fractured steep slopes, locally affected by karst morphologies, particularly present along the Zaccana Mount northern and southern slopes and in the spring emergencies area, characterized by high permeability. The dolomitic limestones show very fissured and karstified features, interstratal karst cavities are also frequently present mainly in the western portion of the San Giovanni spring.
The investigations carried out highlight that the aquifer geometry, the groundwater circulation and the groundwater emergencies are closely connected to the geostructural and karst arrangement. The structural elements present in the hydrostructure, such as faults, tectonic contacts, rock fissuring and fracturing and karst evidences, define deep groundwater flow, determining specific hydrodynamic characteristics of the spring. The Castelluccio Fault constitutes the morphostructural southern limit of the hydrostructure and represents the superimposed permeability threshold of the San Giovanni spring front.
The groundwater flow, predominantly in the NW-SE direction, feeds the several emergencies of the San Giovanni located along a steep slope between 480 m and 504 m a.s.l., with the discharge rate of around 550 l/s, of which only around 150 l/s are used for drinking purposes. The remaining rate is not captured and could be utilized as strategic groundwater resources
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
- …
