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Magnesium and groundwater flow relationship in karst aquifers: a tool for exploitation management of springs // La relazione tra magnesio e circolazione delle acque sotterranee in acquiferi carsici: uno strumento per la gestione della captazione dalle sorgenti
Full text linkKarst aquifers are characterized by different types of groundwater flow, related to different types of permeability due to the simultaneous presence of matrix, fractures and conduits. The presence of a well-developed karst conduit system leads to a rapid circulation of groundwater within the aquifer and a pulse-type response of the spring flow to the rainfall inputs, with a potential fast transport of contaminants from the hydrogeological basin surface to the discharge zones. Supported by hydro chemical analyses of spring water samples and single discharge measurements, it was possible to develop specific mass balance models, correlating ion content to spring flowrates. Specifically, Mg2+ content revealed a reliable application for spring baseflow separation in karst settings. Once the local model has been set, its conservative behaviour, in mostly limestone-dominant aquifers, allows using Mg2+ as a natural tracer of groundwater flow, distinguishing conduit flow (overflow) and diffuse flow (baseflow) occurrence in the spring outlet, without additional discharge measurements. In karst settings, the difficulty in continuously monitoring the spring discharge values makes this application interesting for exploitation management. This study shows the results obtained for two springs located in Central Italy, confirming that monitoring groundwater quality in karst environments is often the key for successfully characterizing springs and assessing the total yield when direct measurements are not available
Recent drought effects on bracciano lake water availability
No full textDrought events are currently increasing in frequency and intensity all over the world as effect of climate change. One of the most related environmental issue is water resource scarcity, which is now becoming an emergency also for several industrialized countries in the Mediterranean area. In the summer of 2017, all Italian territory suffered from an extreme drought event that caused huge depletions of both groundwater and surface water availability. In particular, Bracciano Lake, which is one of the largest surface water resource of Central Italy, showed the largest water level drop in 50 years of observation, with a critic impact on the Lake’s ecological system. This event highlighted once again the key-role of water shortage analysis, whose main goal is studying the relationship between rainfall deficit and water resources availability. Moreover, their long-term trends need to be studied in order to find sustainable solutions for the increasing water demand of the population. In particular, in this paper, data related to time series of about 60 years have been analyzed with the aim of finding highly significant relationships between Bracciano Lake level drops at different time scales, and the SPI (Standard Precipitation Index), which is currently the most widely used hydrological drought indicator. This study aims to demonstrate that specific drought indices may be useful tools for water system management
Hydraulic conductivity estimation using low-flow purging data elaboration in contaminated sites
Full text linkHydrogeological characterization is required when investigating contaminated sites, and hydraulic conductivity is an important parameter that needs to be estimated. Before groundwater sampling, well water level values are measured during low-flow purging to check the correct driving of the activity. However, these data are generally considered only as an indicator of an adequate well purging. In this paper, water levels and purging flow rates were considered to estimate hydraulic conductivity values in an alluvial aquifer, and the obtained results were compared with traditional hydraulic conductivity test results carried on in the same area. To test the applicability of this method, data coming from 59 wells located in the alluvial aquifer of Malagrotta waste disposal site, a large area of 160 ha near Rome, were analyzed and processed. Hydraulic conductivity values were estimated by applying the Dupuit's hypothesis for steady-state radial flow in an unconfined aquifer, as these are the hydraulic conditions in pumping wells for remediation purposes. This study aims to show that low-flow purging procedures in monitoring wells-carried out before sampling for groundwater characterization-represent an easy and inexpensive method for soil hydraulic conductivity estimation with good feasibility, if correctly carried on
Preliminary validation of an indirect method for discharge evaluation of Pertuso Spring (Central Italy)
Full text linkThis paper deals with the results of the first year of the Environmental Monitoring Plan, related to the catchment project of Pertuso Spring, which is going to be exploited to supply an important water network in the South part of Roma district. The study area is located in the Upper Valley of the Aniene River (Latium, Central Italy), in the outcrop of Triassic-Cenozoic carbonate rocks, and belong to an important karst aquifer. Pertuso Spring is the main outlet of this karst aquifer and is the one of the most important water resource in the southeast part of Latium Region, used for drinking, agriculture and hydroelectric supplies. Karst aquifer feeding Pertuso Spring is an open hydrogeological system aquifer characterized by complex interactions and exchanges between groundwater and surface water which influence the aquifer water budget. Thus, evaluation of groundwater discharge from this karst spring can be affected by difficulties in performing measurements because of the insufficient knowledge about water transfer processes in the hydrological cycle and geometry of drainage conduits.
The aim of this paper is to assess the interactions between karst aquifer feeding Pertuso Spring and Aniene River based on stream discharge measurements and water geochemical tracer data in order to validate an indirect method for karst spring discharge evaluation. As a matter of fact, in this paper, there are presented the results of the application of Magnesium as a reliable tracer of karst spring discharge. This indirect method is based on the elaboration of surface water discharge measurements in relationship with Mg2+ concentration values, determined as for groundwater, coming from Pertuso Spring, as for surface water sample, collected upstream and downstream of Pertuso Spring, along Aniene River streamflow. The application of Magnesium as an environmental tracer provides a means to evaluate discharge of Pertuso Spring, as it came up to be a marker of the mixing of surface water and groundwater. On the other hand, the Magnesium ion concentration provides information for the identification of groundwater flow systems and the main hydrogeochemical processes affecting the composition of water within the karst aquifers
Effects of climate change on groundwater feeding the Mazzoccolo and Capodacqua di Spigno Springs (Central Italy): First quantitative assestments
No full textIn Italy, the summer of 2017 was characterized by serious problems related to the water crisis that affected the entire national territory. The Municipality of Formia, as well as many other territories in the Latina Province, had to face heavy rationing of the water supply during the summer, with consequent inconvenience for the population. In this paper, two spring and their relative aquifers were studied: the Mazzoccolo Spring and the Capodacqua di Spigno Spring. For both aquifers, a hydrogeological water balance was calculated based on the collection of thermo-pluviometric data on an appropriate time series, at the meteorological stations present within and around the study area. The main goal was to establish, in the context of current climate change, the potential of the aquifers that feed these water resources. For the calculation of the active recharge, in order to have an estimation value of the supply volumes, data referred to four meteorological stations in the study area for a time series of 40 years (1959-1999) were collected and processed. The stations considered are the following: Gaeta, Itri, Esperia and SS Cosma e Damiano pluviometric stations. Each basin has been divided into finished square elements (FSE), with a size of 10000 m2, using a GIS software. The value of the effective infiltration to assign to each cell is a function of the annual rainfall value and the annual evapotranspiration value, both referred to the cell itself. The sum of all the values referred to each cell of the grid, provided the estimation of the aquifer annual average recharge as average annual volume. The same procedure was used for maximum, minimum and medium values of the rainfall on the time series considered and for the single annual rainfall value of 2017. Results confirmed the extraordinary nature of the drought event that occurred during the recharge period of 2017, showing a huge decrease of the average available water volume. In conclusion, for the Mazzoccolo and Capodacqua di Spigno Springs, future interventions are going to be planned for the catchment optimization in order to overcome any future possible water crises, even considering the permanent reserves, without compromising their medium and long term availability and their quality
Determination of glucose, fructose, sucrose and lactose in chocolate based matrices using HPIC with amperometric pulsed detection
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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
A proposal of conceptual model for Pertuso Spring discharge evaluation in the Upper Valley of Aniene River
Full text linkThe Upper Aniene River basin is part of a large karst aquifer, which interacts with the river, and represents the most important water resource in the southeast part of Latium Region, Central Italy, used for drinking, agriculture and hydroelectric supplies.
This work provides hydrogeochemical data and their interpretations for 1 spring and 2 cross section of Aniene River, monitored from July 2014 to December 2015, in the Upper Valley of Aniene River, to identify flow paths and hydrogeochemical processes governing groundwater-surface water interactions in this region.
These activities deal with the Environmental Monitoring Plan made for the catchment work project of the Pertuso Spring, in the Upper Valley of Aniene River, which is going to be exploited to supply an important drinking water network in the South part of Rome district. Discharge measurements and hydrogeochemical data were analyzed to develop a conceptual model of aquifer-river interaction, with the aim of achieving proper management and protection of this important hydrogeological system.
All groundwater samples are characterized as Ca-HCO3 type. Geochemical modeling and saturation index computation of the water samples show that groundwater and surface water chemistry in the study area was evolved through the interaction with carbonate minerals. All groundwater samples were undersaturated with respect to calcite and dolomite, however some of the Aniene River samples were saturated with respect to dolomite. The analysis of Mg2+/Ca2+ ratios indicates that the dissolution of carbonate minerals is important for groundwater and surface water chemistry, depending on the hydrological processes, which control the groundwater residence time and chemical equilibria in the aquifer
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
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