Intrinsic Vulnerability Assessment of a Confined Carbonatic Aquifer: the Brindisi Plain Case (Southern Italy)

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Analysis of the potential contamination risk of groundwater resources circulating in areas with anthropogenic activities

The area investigated is located in the province of Brindisi (Italy). It is a generally flat area separated from the nearby carbonatic plateau of the Murgia by quite indistinct and high fault scarps. As regards the geological features, carbonatic basement rocks and post-cretaceous terrains made up of calabrian calcarenites and middle-upper Pleistocenic marine terraced deposits can be distinguished. <P style='line-height: 20px;'> In the examined area there are two different hydrogeological environments. The first is represented by deep groundwater, the main groundwater resource in Apulia. <P style='line-height: 20px;'> The second hydrogeological environment, now of lesser importance than the deep aquifer in terms of size and use, is made up of some small shallow groundwater systems situated in post-calabrian sands and located in the eastern area. <P style='line-height: 20px;'> During some sampling cycles carried out in the studied area, water was withdrawn from both the deep aquifer and from the shallow groundwater. For every sample, the necessary parameters were determined for the physical and chemical characterisation of two different hydrogeological environments. Moreover, some chemical parameters indicating anthropogenic activities were determined. <P style='line-height: 20px;'> Analysis of the aerial distribution of the measured parameters has shown some main areas subject to different conditions of contamination risk, in accordance with the hydrogeological and geological features of the investigated area. <P style='line-height: 20px;'> In the south-eastern part of the investigated area, the important action performed by the surface aquifer for protecting the deep groundwater from contamination of anthropogenic origin is clear.<p> On the other hand, in the shallow groundwater, areas of nitrate and nitrite contamination have been identified, which result from the extensive use of fertilizers

Hydrogeological problems relating to the construction of an underground metro system in Bari urban and suburban areas

Many problems are related to the construction of an underground metro system in Bari urban and suburban areas, excavations involving namely dolomite-limestones in both anhydrous and saturated zones and low-thickness postcretaceous covers. A number of rock-sealing methods are reviewed. Consideration is given to the rock hydrodynamic characteristics of the urban area alongside impacts on groundwater flows

Geomorphological, pedological, and hydrological characteristics of karst lakes at Conversano (Apulia, southern Italy) as a basis for environmental protection

The land around Conversano (Apulia, southern Italy) is part of the Murge karst, interesting limestones and dolomitic limestones of Upper Cretaceous age, in a flat environment with sub-horizontal setting. Dolines and karst depressions are the most typical landforms in the area. Filling of these landforms with eluvial deposits locally created the possibility of water stagnancy at the surface. The Conversano territory presents ten karst lakes that represented, until some decades ago, the only water resource available for the local people, who built the typical bell-shaped wells to collect water volumes satisfying local needs during the dry season. Currently, these lakes have no great importance as water supplies, but represent habitats of great naturalistic value that are still able to support the ecological functionality and the wet environments with self-vegetation. Hydrological and hydrogeological studies have been carried out with the aim to fully estimate the related environmental problems. For this purpose, the hydrogeologic data of historical time series have been collected and compared to those of the last 5 years; successively, according to the Thornthwaite method, a hydrological monthly balance has been evaluated to quantify the distribution of water volumes interacting annually between the surface water bodies and the underlying carbonate groundwater. This evaluation has highlighted the need to carefully consider all the parameters concurring to a right definition of water balance for a karst environment, where pedological features, climatic conditions and anthropogenic modifications to the environment represent the elements of a very delicate system. Particularly, on the basis of recent soil map and field surveys, a re-evaluation of the available water capacity, estimated in some 40 mm, has been carried out. The studies have highlighted the need to extend the environmental protection rules to larger areas around the lakes, e.g. at the catchment scale, with definition of buffer zones; in this manner, it will be possible to constantly monitor the protected land and the local anthropogenic activities, that represent real polluting sources for both the surface water resources and the underlying carbonate groundwaters. © Springer-Verlag 2008

Hydrogeological problems relating to the construction of an underground metro system in Bari urban and suburban areas

Many problems are related to the construction of an underground metro system in Bari urban and suburban areas, excavations involving namely dolomite-limestones in both anhydrous and saturated zones and low-thickness postcretaceous covers. A number of rock-sealing methods are reviewed. Consideration is given to the rock hydrodynamic characteristics of the urban area alongside impacts on groundwater flows.PublishedCernobbioope

The piezometric chemical phisical monitoring of Murgia and Salento groundwater (Apulia)

l territorio murgiano-salentino, data la sua natura prevalentemente carsica, è praticamente privo di risorse idriche superficiali; d’altra parte lo stesso è dotato di risorse idriche sotterranee anche notevoli, che hanno a tutt’oggi consentito, per vaste aree, lo sviluppo delle attività produttive. La natura di tali risorse idriche sotterranee, le particolari fenomenologie che regolano i processi di alimentazione, di deflusso e di svuotamento nonché l’influenza esercitata dal mare, rendono quanto mai delicato il problema di una oculata gestione e di un corretto impiego delle acque sotterranee. Sono dunque di attualità i problemi relativi alla degradazione delle acque sotterranee, sia per fenomeni di contaminazione salina che per fenomeni di inquinamento antropico, derivanti dalla pratica di utilizzare il sottosuolo come ricettacolo di reflui anche non trattati. La corretta gestione e tutela del patrimonio idrico sotterraneo rappresenta quindi un obiettivo prioritario da perseguire a breve termine; a tal fine si fa ricorso a due tipi di approccio, attuati a diversa scala: a scala regionale si opera un controllo continuo dei fenomeni evolutivi che interessano la disponibilità e la qualità delle risorse idriche sotterranee; a scala locale, con il massimo dettaglio, si studiano le iniziative di tutela delle acque sotterranee di maggior pregio destinate al consumo umano attraverso la delimitazione delle aree di salvaguardia

Changes on groundwater flow and hydrochemistry of the Gran Sasso carbonate aquifer after 2009 L'Aquila earthquake

The earthquake that struck L'Aquila on April 6 2009 (Mw 6.3) directly affected the Gran Sasso aquifer. Co-seismic and post-seismic changes in groundwater discharge and in hydrochemistry, possibly induced by the earthquake, were observed. Spot and monitoring measurements of the spring discharge, of water table level and of the main physico-chemical parameters of spring waters (T, pH, electrical conductivity, major ions and Rn-222) were thus carried out to determine the effects of the L'Aquila earthquake on groundwater at regional and local scale, to be compared with available data collected since the 1990s. Short- and mid-term effects have been observed in the groundwater flow at recharge and discharge areas. The following short-term effects have been observed: i) the sudden disappearance of some springs located along the surface trace of the Paganica Fault; ii) an immediate discharge increase of the Gran Sasso highway tunnel drainages (+20%) and of other springs (+10%); iii) a progressive increase of the water table elevation (+1m) at the boundary of the Gran Sasso aquifer during the following month; iv) a sudden lowering of the water table in the recharge area. Similar post-seismic effects have been recorded in the following 20 months, when spring discharge and water table remain higher than the pre-seismic ones in discharge zones. A conceptual model of the earthquake consequences on the Gran Sasso aquifer is proposed herein. The short-term hydrologic effects registered immediately after the mainshock have been caused by a pore pressure increase related to elasto-static aquifer deformation. Apart from the contribution of seasonal recharge observed in 2009-10, mid-term effects observed in the 20 months following the mainshock suggest that there was a change in groundwater hydrodynamics. Supplementary groundwater that flows toward aquifer boundaries and springs in discharge areas reflects a possible increase in hydraulic conductivity in the recharge area. This increase is probably related to fracture cleaning and/or dilatancy. Additional monitoring including hydrochemical data allows a refinement of the proposed model. The outcomes of the hydrochemical spot sampling of the pre-seismic (2001-2007), post-seismic (April 2009) and after-seismic (July and September 2009, may 2010) periods, give the following insights: i) post-seismic groundwater of Tempera spring group was more mineralised and richer in Rn-222 than the pre-seismic one; ii) transient changes in pH and calcite saturation index involve the whole aquifer, moving from Tempera springs and spreading from the recharge to discharge areas, causing changes in groundwater hydrochemistry; iii) post-seismic gradual return to previous hydrochemical equilibrium. Both hydrodynamic and hydrochemical observation converge towards a non-permanent increase of the bulk hydraulic conductivity in the aquifer portion close to the Paganica Fault (recharge area and local discharge zone). This fact has caused a lowering of the water table and of the calcite saturation index in recharge areas and simultaneously an increase of water table and flow rate in discharge zones. Complete interpretation of both quantitative and hydrochemical data allows to determine the long-term consequences of this earthquake on the groundwater flow of the Gran Sasso carbonate massif