The increasing groundwater exploitation and contamination risks due to the progressive population growth in coastal areas are emphasized in the case of carbonate coastal aquifers (CCAs), the peculiarities of which, especially in the Mediterranean basin, constitute a scientific matter of worldwide relevance.The CCAs of the Adriatic and Ionian coasts not only ensure the socio-economic development of the populations but feeds with their spring waters valuable wetland and coastal environments with relevant and highly positive effects on ecosystems. The groundwater resources of CCAs are highly vulnerable, especially if affected by karstic phenomena, to the quality and quantity degradation phenomena, not only for the increasing water demand and the decreasing recharge due to climate changes but also in relation to the sea level changes and the pollutant loads due to the contamination occurred in the whole hydrogeological basins.The aim of this study is to offer a systematic and synoptic view, useful for knowledge, management and forecast purposes, contributing to assure enduring availability of high quality groundwater, conciliating water demand satisfaction with the ecological needs of coastal Adriatic and Ionian environments in which the role of groundwater is very important. A geodatabase, collecting information for all carbonate aquifers present along the Adriatic and Ionian coast, have been created. At the core, there is a Geographic Information System, in which are placed the spatial information regarding the geology of aquifers, hydrogeological and geochemical features, together with specific information concerning groundwater use of CCAs. The added value of this database is the availability of a wide bibliography related to CCAs, together with a schematised summary of key information realised considering available information in the whole geodatabase.Starting from this idea, the cooperation between hydrogeologists experts of different areas, have enabled to focus on some specific areas of peculiar hydrogeological interest, as for the CCAs of Apulia (SE Italy), South-western Slovenia, Western and South Croatia, Montenegrian coast (Boka bay) and Western Greece.

The Maltese Islands are located in the central Mediterranean area, on the Malta-Sicily Platform. The archipelago consists of three main islands, Malta, Gozo and Comino, and several small uninhabited islets. Malta, the largest of the three islands, has an extent of 246 km2. The islands present a typical central Mediterranean semi-arid climate with hot dry summers and mild wet winters. The mean-annual rainfall stands at around 550 mm but with high inter- and intra-annual variability. The size of the islands precludes the formation of significant bodies of surface water and therefore the main natural water resources of the islands are the groundwateraquifer systems, in particular the sea-level aquifer systems present in the two larger islands. These aquifer systems are sustained in a carbonate formation (the Lower Coralline Limestone) and take the typical shape of a Ghyben-Herzberg freshwater lens. The high population density of the islands is also reflected in a high level of urban development, where around 25% of the total land area of the islands has been built up. This has altered the physical characteristics of the landscape by significantly increasing the quantity of impermeable surfaces, thereby reducing infiltration processes to groundwater, and increasing the generation of rainwater runoff following rain events. The islands thus present a mixed land-use scenario where domestic, agricultural and commercial activities are operating side by side and depending on the same type of water resources. Of particular reference is the islands' highly developed tourism and recreational sector which places added strain on the water supplies during the dry summer months. Groundwater use for municipal supply is supplemented by the use of sea-water desalination by reverse osmosis. The agricultural sector is mainly dependent on groundwater resources, although water re-use is currently being introduced on a wide scale to supplement (and replace) groundwater use. The use of alternative water resources has thus, in recent years, reduced the pressures on groundwater resources. The aim of this paper is to describe the collaboration between CNR and EWA aimed at the undertaking of a hydrogeological study to support the eventual development of management tools for optimizing the use of Malta's groundwater resources, with specific focus on the main sea-level aquifer system in the island of Malta. As part of this collaboration a review of the hydrogeological environment of the aquifer systems has been undertaken and important data gaps have been identified and are being addressed. The eventual groundwater body. management tool to be developed under this collaborative initiative will enable the formulation and testing of updated groundwater exploitation strategies which ensure the protection of the groundwater bodies from regional and localized sea-water intrusion, whilst taking full consideration of the potential effects of climate change, including the variability o

Carbonate aquifers, located in foreland tectonic settings, could represent important thermal water resources outside the volcanic areas, supplying spas or geothermal installations. Thermal springs constitute the discharge areas of deep marine and continental groundwaters flowing within these carbonate aquifers whose hydraulic conductivity and the relevant geothermal fluid migration are strictly controlled by both the discontinuity network and the karst processes involving the foreland environment. An example of these springs occurs along the south-easternmost portion of the Apulia region (Southern Italy) where some sulphurous and warm waters (22-33 °C) flow out in partially submerged caves located along the coast, thus supplying the spas of Santa Cesarea Terme.These springs are known from ancient times (Aristotele in III century BC) and the physical-chemical features of their thermal waters resulted to be partly influenced by the sea level variations. Some hypotheses about the origin of these warm waters were proposed up to now by previous researches but some uncertainties still exist. For this reason, the area has been selected in order to define the conceptual model of the geothermal resources related to the thermal springs and, as a consequence, the origin of the thermal springs. It is one of the pilot site of the Vigor Project (Evaluation of the geothermal potential of Regions of Convergence), promoted by the Italian Ministry of Economic Development and National Research Council.Santa Cesarea Terme zone is located within the Apulia carbonate platform, the foreland of the southern Apennines, which consists of Jurassic-Cretaceous limestones, thick more than 5 km in the study area and affected by intense karst processes, resting above the Late Triassic evaporite (Burano Fm) and, unconformably, overlaid by Cenozoic calcareous successions. Belonging to a coastal area, the studied groundwater, whose top is located almost to the sea level, is involved in saltwater intrusion and therefore the salt-fresh water interface occurs at some meters below the sea level moving inland. Geological and hydrogeological surveys, including geo-electrical prospecting, and chemical and isotopic analyses of both groundwater and seawater have been carried out. Stable isotopes (?18O, ?D) were used to define the origin of the thermal waters and the recharge mechanism of the geothermal systems while the unstable isotope (3H) was determined for estimating the age of the thermal waters and to define the conceptual model of this low temperature geothermal resource. All the data have been analysed to improve the knowledge of the groundwater flow system, thus assessing the possibility of using low-temperature geothermal fluids to fulfil the thermal needs of the town of Santa Cesarea Terme.In this narrow area, the source of geogenic salinization of spring groundwater was referred to ascending very deep groundwater, more saline than current sea water.The geochemical com

The Apulian peninsular coastline (940 km) includes many urbanized areas and coastal wetlands, the latter in same cases interested by huge touristic transformations. The region is dominated by large and deep karstic and coastal aquifers and by some minor porous coastal aquifers the coastal outflow of which create tens of coastal wetlands. They should be considered dependent by groundwater outflow and by dynamic equilibria with sea, in terms of seawater intrusion and ingression. For a long time, these areas were considered unproductive, sources of malaria, and were depopulated. During the second half of the last century, relevant reclamation works were realized, the coastal areas have assumed a role of primary importance for the social and economic development. This has led to a growing anthropic pressure along the coast that has led to a progressive deterioration of the coastal wetland environments. High vulnerability to pollution, overexploitation trend, increasing seawater intrusion effects and global groundwater quality decrease threaten the hydrological and ecological equilibria of these water systems. The collective awareness of the important role played by the transition environments, gave rise to a conceptual innovation on the protection and enhancement of wetlands.The research is finalized to define an inventory of the regional coastal wetlands, focusing on that the role of groundwater outflow is relevant if not prevailing. For each of these wetlands were defined a number of information and characteristics based on bibliographical knowledge and field surveys. The geological and hydrological conditions were recognized. On this basis, the hydrological and hydrogeological conceptualization was ended, permitting to define a steady state hydrological balance of wetlands. The role of seawater intrusion and ingression and the role of these in terms of salinity is analyzed. The scope is to offer a global overview of these wetlands to promote a systematic approach to their safeguard.

The Mar Piccolo basin is an internal sea basin located along the Ionian coast (Southern Italy), and it is surrounded primarily by fractured carbonate karstic environment. Because of the karstic features, the main continental water inflow is from groundwater discharge. The Mar Piccolo basin represents a peculiar and sensitive environment and a social emergency because of sea water and sediments pollution. This pollution appears to be caused by the overlapping effects of dangerous anthropogenic activities, including heavy industries and commercial and navy dockyards. The paper aims to define the contribution of subaerial and submarine coastal springs to the hydrological dynamic equilibrium of this internal sea basin. A general approach was defined, including a hydrogeological basin border assessment to detect inflowing springs, detailed geological and hydrogeological conceptualisation, in situ submarine and subaerial spring measurements, and flow numerical modelling. Multiple sources of data were obtained to define a relevant geodatabase, and it contained information on approximately 2,000 wells, located in the study area (1,600 km2). The conceptualisation of the hydrogeological basin, which is 978 km2 wide, was supported by a 3D geological model that interpolated 716 stratigraphic logs. The variability in hydraulic conductivity was determined using hundreds of pumping tests. Five surveys were performed to acquire hydro-geochemical data and spring flow-yield measurements; the isotope groundwater age was assessed and used for model validation. The mean annual volume exchanged by the hydrogeological basin was assessed equal to 106.93 106 m3. The numerical modelling permitted an assessment of the mean monthly yield of each spring outflow (surveyed or not), travel time, and main path flow.

Carbonate aquifers in foreland tectonic settings can host important thermal springs although located inareas commonly not characterized by regional high heat flow values. In these cases, when thermal springsare located close or along the coastlines the subaerial and/or submarine thermal springs constitute theoutflow of marine groundwater, flowing through localized fractures and karsitic rock-volumes. This isthe case of springs occurring along the south-easternmost portion of the Apulia region (Southern Italy)where few sulphurous and warm waters (22-33oC) outflow in partially submerged caves located alongthe shoreline, thus supplying the historical spas of Santa Cesarea Terme. Here, with the aim to define theorigin of the thermal fluids and their deep path, we carried out the geo-structural survey of the area anddetailed hydrogeological and geochemical analyses of the thermal spring fluids. In particular, the isotopes18O, D,13C in DIC,34Ssulphate,34Ssulphide,3He/4He ratio and13C in CO2were used to define the origin ofthe thermal water and the recharge mechanism of the geothermal system while the isotopes3H and14Cwere determined for estimating the age of the thermal waters, resulting in older than roughly twentythousands years BP. The results indicate that the thermal springs are fed by marine water, having reachedSanta Cesarea Terme through a localized fracture network. This affects the evaporitic and carbonatic rocksthat characterize the substratum of the Adriatic Sea in the offshore.

The Mar Piccolo (literally "small sea"), a sea internal basin which is part of the Taranto Gulf, located along theIonian coast in Southern Italy (Apulia region), represents a peculiar and sensitive environmental area and a social emergency due to the pollution of sea water and sediments due to the effect of the neat industrial area of Taranto. Thepaper describes the methodological approach to define the conceptualisation of the hydrogeological basin of main subaerial and submarine coastal springs of the Mar Piccolo. The geochemical discussion concerning spring groundwater was finalised to define the effect of seawater intrusion. These waters are characterised by high values of electrical conductivity and high concentrations of alkaline ions (Na+ and K+) and chloride ion and show typical chemical characteristics of fresh groundwater contaminated by seawater intrusion. The groundwater composition of the subaerial springs of Mar Piccolo is controlled by the combined effects of calcite dissolution and ion exchange. A basicmodel of the coastal aquifer was realised with the purpose to assess the mean annual and monthly value of spring outflows in Mar Piccolo. The computer codes selected for numerical groundwater modelling were MODFLOW and SEAWAT. The active domain of the model was about 978 km2 with a total number of 391200 cells. The researchpursues the knowledge of the hydrological balance of the internal sea, the geochemistry of groundwater, and the groundwater discharge effect on the ecological equilibrium of the coastal environment in the framework of a wide Italian research program called RITMARE.

The data presented in this article are related to the research article described by (Cossu et al., 2018).The data set for this article contains chemical analyses of groundwater and leachate, isotope analysis of groundwater and leachate around a group of landfills located in the municipality of Conversano, close to Bari, the main town of the Apulia Region (Southern Italy). Groundwater samples were collected from eighteen wells.The hydrogeological and chemical study was used to define geochemical features, groundwater and leachate characteristics and to study their potential macroscopic mixing.The land use analysis highlighted quantity and type of used fertilizers permitting to compare these with groundwater in terms of isotopic signature.

The coastal carbonate Apulian aquifers, located in southern Italy, feed several coastal fresh springs and constitute the main local source of high quality water. The Santa Cesarea Terme cave system is almost unique case of hypogenic coastal spring caves, located along the Adriatic Sea coastline and hosting spring coastal outflow of mixed groundwater (from 22°C to 33°C) mainly of thermal groundwater due to infiltration offshore, in the sea bottom, and pure fresh groundwater due rainfall infiltration. Thermal springs and the outflow system are strictly controlled by both the discontinuity network and the karst processes involving the foreland environment. Detailed geoelectrical prospecting were carried out to bound the upflow continental area of this system, considering the geoelectrical effects of deep water mixing with different salinity and temperature close the Adriatic coast.

The progressive population growth in coastal areas and the increasing groundwater discharge, together withpeculiarities of karst coastal aquifers constitute a huge worldwide problem, particularly relevant for coastal aquifers ofthe Mediterranean basin (Tulipano et al., 2005).Karst aquifers in coastal regions are well known to be highly vulnerable to the overexploitation of groundwaterresources, both from water increasing demand than from decreasing aquifer recharge due to climate changes. The coastalcarbonate aquifers of the Mediterranean Sea, in particular the Adriatic and Ionian coast that extend between westernGreece and Italy up to the eastern coast of Sicily not only ensure the socio-economic development of the populations butfeeds with spring waters valuable wetland environments with negative effects on ecosystems (Barrocu, 2003; Bonacci,2014; Eftimi & Zojer, 2015; Polemio, 2016).The aim of this study is to develop management and forecast tools to identify the best way to assure enduringavailability of high quality groundwater, and conciliate irrigation and drinking water demands. A geodatabase, collectinginformation for all carbonate aquifers present along the Adriatic and Ionian coast, will be first created. At the core thereis a Geographic Information System, in which are placed the spatial information regarding the geology of aquifers,hydrogeological and geochemical features, together with climatic conditions and specific information concerning past,present and future groundwater usage.The availability of tools that allow the integrated analysis of local hydrogeological situations, in reference to the widerareas where they are located, allows numerous applications. The system, in fact, is not only aimed to archiving, queryingand mapping, but also to operate spatial analysis and the implementation of calculation systems, to return thehydrogeological conceptual models, supporting both the management of groundwater resources and the knowledge forthe protection of coastal environments, and groundwater in general.

The attention of local communities and authorities was focused on the level of groundwater nitrate of a wide coastal karstic aquifer, not far from the town of Bari (southern Italy), worried about the potential effect of sanitary and unsecure landfills. The study considered each potential source of nitrate, considering the type of local land use: mineral fertilizers, septic waste, animal manure and landfill leachate. The hydrochemical investigation was conducted on groundwater of the limestone aquifer and on leachate samples. The most important chemical parameters (Ca2+, Mg2+, Na+, K+, Cl-, SO42-, NO3-) and some minor constituent (Fe, Mn, Hg, As, Zn) are taken into account. In particular the environmental isotopes of hydrogen (H), carbon (C), nitrogen (N) and oxygen (O) were used to identify the groundwater provenance and geochemical reactions. The stable isotopes oxygen-18 (18O) and deuterium (2H) were used to investigate the origin of water in the aquifer system in the study area. The combination of NO3- concentration with ?15N-NO3- and 18O-NO3- in water also provides valuable information for identifying different sources of NO3- to the coastal aquifer. Samples of groundwater and leachate were analysed for 13C and Tritium (3H). Previous studies have demonstrated that the biogeochemical processes within the landfill environment can produce a unique composition for these isotopes, therefore they can be utilized successfully to delineate leachate influence. On-going results are discussed in details for each type of potential source of groundwater quality degradation.

Where the unique natural water resource is groundwater, is the case of wide karstic area, the attention and the susceptibility of local communities and authorities to groundwater risks can be so high to determine relevant misunderstanding due the existence of a number of landfills. For solve this kind of situation, a multi-methodological approach is proposed with the purpose to clarify the role of landfill leakage in terms of groundwater quality degradation risks.The selected study area (SSA) is narrow portion of a wide and deep coastal karstic aquifer, for these characteristics to be considered a case of high complexity and susceptibility. Mainly nitrate and secondly iron groundwater concentration were considered anomalously high in some well of the SSA, not far from Bari (main town of Apulia, a region of Southern Italy), worried about the potential effects of some landfills located in SSA. Five landfills have operated from 1975, one after the other, using increasing safety and technological devices to reduce risks due to leachate leakages with consequent groundwater quality degradation. The multi-methodological approach, which could be potentially applied worldwide, includes: the hydrogeological site characterization; the chemical study and the multi-isotope characterization of groundwater and leachate; the land use analysis and the estimation of nitrogen contributions deriving from agricultural activities, focusing on the use of fertilizers; themineralogical study of groundwater suspended particles to define the origin of some substances, focusing on iron and manganese, relevant for the SSA. The hydrogeological site characterisation highlighted the local peculiarties of the aquifer.The chemical study was focused on the most important chemical features (Ca2+, Mg2+, Na+, K+, Cl-, SO4 2-, NO3-), especially to define geochemical peculiarties, along with some minor chemical elements were taken into account, to define globally the groundwater quality and the leachate characteristics.The environmental isotopes of hydrogen (H), carbon (C), nitrogen (N) and oxygen (O) were used to identify the groundwater provenance and the most relevant geochemical reactions. The oxygen-18 (18O) and deuterium (2H) stable isotopes were used to investigate the origin of water in the aquifer system of the study area. The combination of NO3- concentration with ?15N-NO3-and 18O-NO3- in groundwater also provides valuable information for identifying the true sourcesof anthropoghenic NO3-. Groundwater and leachate samples were analysed for 13C and Tritium(3H), completing the framework of knowledge on the role of leachate on groundwater as previous studies have demonstrated that the biogeochemical processes occurring within the landfill environment can produce a unique composition of these isotopes and therefore they can be utilized successfully to delineate the potential leachate influence. The land use analysis highlighted quantity and type of used fertilizers pe

Geochemical processes occurring at the seawater/freshwater interface were studied for the aquifer feeding the Santa Cesarea thermal springs, located along the coastal sector of the Salento peninsula (southern Italy). Inthis coastal area, seawater is moving into the freshwater carbonate aquifer, pushing so inland beneath the freshwater and creating so an extremely active geochemical environment. In the transition zone, the interaction between the freshwater/saltwater and the aquifer rocks could affect the geochemical composition of the groundwater itself, modifying it even profoundly, as discussed in the paper. The geochemical processes occurring at a seawater/freshwater interface are also described together with the chemical composition of Santa Cesarea thermal springs.

The progressive population growth in coastal areas and the increasing groundwater discharge, together with peculiarities of carbonate coastal aquifers constitute a huge worldwide problem, particularly relevant for coastal aquifers of the Mediterranean basin. Carbonate aquifers in coastal regions are well known to be highly vulnerable, especially if hit by karstic phenomena, to the quality and quantity degradation of groundwater resources, not only for the increasing water demand and the decreasing recharge due to climate changes. The coastal carbonate aquifers of the Mediterranean Sea, in particular the Adriatic and Ionian coast that extend between western Greece and Italy up to the eastern coast of Sicily, not only ensure the socio-economic development of the populations but feeds with spring waters valuable wetland environments with negative effects on ecosystems.The aim of this study is to offer systematic and synoptic knowledge, useful to management and forecast tools, to assure enduring availability of high quality groundwater, conciliating water demand satisfaction with the ecological needs of coastal environment also in the case of transnational situations. A geodatabase, collecting information for all carbonate aquifers present along the Adriatic and Ionian coast, have been created. At the core, there is a Geographic Information System, in which are placed the spatial information regarding the geology of aquifers, hydrogeological and geochemical features, together with climatic data and specific information concerning past, present and future groundwater use. The availability of tools that allow the integrated analysis of local hydrogeological situations, in reference to the wider areas where they are located, allows numerous applications. The system, in fact, is not only aimed to archiving, querying and mapping, but also to operate spatial analysis and the implementation of calculation systems, to return the hydrogeological conceptual models, supporting both the management of groundwater resources and the knowledge for the protection of coastal environments, and groundwater in general.

Carbonate aquifers, located in foreland tectonic settings, could represent important thermal water resources outside the volcanic areas, supplying spas or geothermal installations. Thermal springs constitute the discharge areas of deep marine and continental groundwater flowing within these carbonate aquifers whose hydraulic conductivity and the relevant geothermal fluid migration are strictly controlled by both the discontinuity rock network and the karst processes involving the foreland environment. An example of these springs occurs along the south-easternmost portion of the Apulia region (Southern Italy) where some sulphurous and warm waters (22-33 °C) flow out in partially submerged caves located along the coast, thus supplying the spas of Santa Cesarea Terme (referred as SCT in the following). Some hypotheses about the origin of these warm waters were proposed up to now by previous researches but some uncertainties still exist. For this reason, the SCT area was selected in order to define the conceptual model of the geothermal resources related to the thermal springs and, as a consequence, the origin of the thermal springs. This SCT area is one of the pilot site of the Vigor Project (Evaluation of the geothermal potential of Regions of Convergence), promoted by the Italian Ministry of Economic Development and National Research Council. Geological and hydrogeological surveys, including geo-electrical prospecting, and chemical and isotopic analyses of both groundwater and seawater were carried out. Stable isotopes (e.g. ?18O, ?D) were used to define the origin of the thermal waters and the recharge mechanism of the geothermal systems while the radiocarbonate 14C was determined for estimating the age of the thermal waters.All the geological, hydrogeological and geochemical data acquired during the project were so analyzed in order to define the conceptual model of the SCT geothermal resource. The thermal waters arise from ancient seawaters infiltrated at great depth within the seabed substratum, located in front of the Santa Cesarea coastal sector. Moreover allthe data were examined to improve the knowledge of the groundwater flow system, thus assessing the possibility of using low-temperature geothermal fluids to fulfill the thermal needs of the town of Santa Cesarea Terme.

All natural waters contain dissolved minerals from interactions with atmospheric and soil gases, mixing with other solutions, and/or interactions with the biosphere and lithosphere. In many cases, these processes resultin natural waters containing solute or salinity above concentrations recommended for a specified use, which creates significant social and economic problems. Groundwater salinisation can be caused by natural phenomena and anthropogenic activities. For the former case, we can distinguish terrestrial and marine phenomena. Approximately 16% of the total are a of continental earth is potentially in volvedin groundwater salinisation. Seawater intrusion can be considered to be the primary phenomenon for study interms of groundwater salinisation. Three schematic approaches to the protection of groundwater via salinisation mitigation and/or groundwater salinity improvement are described; these approaches are the engineering approach, the discharge management approach, and the water and land management approach. The engineering approach is realised with the purpose of controlling the salinisation, optimising the well discharge with specific technical solutions and/or completing works to improve the quality and/or quantity of the discharged fresh groundwater. The discharge management approach encompasses at least an entire coastal aquifer and defines rules concerning groundwater utilisation and well discharge. The water and land management approach should be applied on there gional scale. The practical study of Apulian karstic coastal aquifers is discussed in detail. Previously experienced management difficultie sare described, as well as a proposed multi-methodological approach based on monitoring networks, the spatiotemporal analysis of groundwater quality changes, and multiparameter well logging. The core of this approach is the definition of the salinity threshold value be tween pure fresh groundwater and any fresh and saline groundwater mixture. The basic or single tools were defined to be simple, quick and cost-effective to be applicable to the widestrange of situations.

Where the unique natural water resource is groundwater, the attention and the susceptibility of local communities and authorities to groundwater quality degradation risks can be so high to determine relevant problems to waste management, especially for landfills in operation or to be realised. A multi-methodological approach was suggested with the purpose to clarify the role of landfill leakage on groundwater quality degradation.The selected study area (SSA) hosts some landfills in a narrow portion of a wide and deep coastal karstic aquifer, for these characteristics to be considered a case of high hydrogeological complexity and vulnerability. News concerning nitrate and secondly iron groundwater concentration anomalously high caused concern in the population and strong local opposition to landfills.The multi-methodological approach includes: the hydrogeological site characterization; the chemical study and the multi-isotope characterization of groundwater and leachate; the land use analysis and the estimation of nitrogen contributions deriving from fertilizers; the mineralogical study of groundwater suspended particles to define the role of natural soil substances.The hydrogeological site characterisation highlighted the local peculiarities of the aquifer. The chemical study was used to define geochemical features, groundwater and leachate characteristics and their macroscopic mixing.The environmental isotopes of hydrogen, carbon, nitrogen, and oxygen were used to investigate the groundwater origin, the most relevant geochemical reactions, the existence of groundwater-leachate mixing, and the sources of anthropogenic NO3-. The land use analysis highlighted quantity and type of used fertilizers permitting to compare these with groundwater in terms of isotopic signature. The mineralogical study demonstrated the role of suspend natural particles due the presence of terre rosse (red or residual soils) in groundwater.The approach confirmed that there are not the groundwater quality degradation effects of landfills, contributing to reassure population and institutions, simplifying the waste management.

The attention of local communities and authorities was focused on the level of nitrate concentration in ground-water of a wide coastal karstic aquifer, not far from the town of Bari (southern Italy), worried about the poten-tial effect of sanitary and unsecure landfills. Five landfills have operated from 1975, one after the other, using increasing safety and technological devices to reduce risks due to leachate leakages with consequent groundwater quality degradation.A multi-methodological approach was conducted to define the origin of nitrate contamination. The approach includes hydrogeological site characterization, chemical and isotopic study of groundwater and leachate, land use analysis and estimation of nitrogen contributions deriving from agricultural activities, focus-ing on the use of fertilizers and mineralogical study of groundwater suspended particles to define the origin of the iron and manganese in the water samples.In particular, the environmental isotopes of oxygen-18 (18O) and deuterium (2H) were used to investigate the origin of water in the aquifer system of the study area. The combination of NO3- concentration with ?15N-NO3- and 18O-NO3- in water also provides valuable information for identifying different sources of NO3- to the coastal aquifer. Groundwater and leachate samples were analyzed for 13C and Tritium (3H). Previous studies have demonstrated that the biogeochemical processes occurring within the landfill environment can produce a unique composition of these isotopes and therefore they can be utilized successfully to delineate the potential leachate influence.

Natural waters contain dissolved minerals from interactions with atmospheric and soil gases, mixing with othersolutions, and/or interactions with the biosphere and lithosphere. In many cases, these processes result in natural waterscontaining solute or salinity above concentrations recommended for a specified use, which creates significant social andeconomic problems.There are different measures, actions and practices for managing groundwater when the natural resource is exposedto salinization. Some of these measures have a mitigation objective. Other measures have a more adaptive approach andaccept the high groundwater salinity but adjusting the groundwater use so that it is not harmful.Moving from the lowest to the highest complexity, these approaches are the engineering approach, the dischargemanagement approach, and the water and land management approach.This research classifies the sources of groundwater salinization and defines in detail different management approachesto protecting the groundwater through salinization mitigation and/or groundwater salinity improvements. By focusing theattention on the effect of seawater intrusion, practical solutions are proposed.

All natural waters contain dissolved minerals from interactions with atmospheric and soil gases, mixing with other solutions, and/or interactions with the biosphere and lithosphere. In many cases, these processes result in natural waters containing solute or salinity above concentrations recommended for a specified use, which creates significant social and economic problems.Groundwater salinisation can be caused by natural phenomena and anthropogenic activities. For the former case, we can distinguish terrestrial and marine phenomena. Approximately 16% of the total area of continental earth is potentially involved in groundwater salinisation. Seawater intrusion can be considered to be the primary phenomenon to be studied in terms of groundwater salinisation.Three schematic approaches to the protection of groundwater via salinisation mitigation and/or groundwater salinity improvement are described based on the classifications of the primary salinisation sources and focusing on the effect of seawater intrusion. The complexity of these approaches generally increases due to difficulties caused by groundwater quality and quantity degradation and increased demand for quality water. In order from the lowest to the highest complexity, these approaches are the engineering approach, the discharge management approach, and the water and land management approach. The engineering approach is realised on the local or detailed scale with the purpose of controlling the salinisation, optimising the well discharge with specific technical solutions and/or completing works to improve the quality and/or quantity of the discharged fresh groundwater. The discharge management approach encompasses at least an entire coastal aquifer and defines rules concerning groundwater utilisation and well discharge. The water and land management approach should be applied on the regional scale. Briefly, this approach becomes necessary when one or more need creates an overall framework of high-quality water scarcity. These conditions, sometimes combined with an awareness of negative environmental effects, force people to accept new water saving practices and land use modifications. As the natural effects of salinisation can be enhanced by a multiplicity of human actions, the discharge management approach and the water and land management approach should generally be applied by water authorities or institutional and governmental organisations that are responsible for groundwater quality and availability.The practical study of Apulian karstic coastal aquifers is discussed in detail. Previously experienced management difficulties are described, as well as a proposed multi-methodological approach based on monitoring networks, the spatiotemporal analysis of groundwater quality changes, and multiparameter well logging. The core of this approach is the definition of the salinity threshold value between pure fresh groundwater and any fresh and saline groundwater mixture. The basic or si

Natural waters contain dissolved minerals from interactions with atmospheric and soil gases, mixing with other solutions, and/or interactions with the biosphere and lithosphere. In many cases, these processes result in natural waters containing solute or salinity above concentrations recommended for a specified use, which creates significant social and economic problems. Groundwater salinisation can be caused by natural phenomena and anthropogenic activities. For the first case, we can distinguish terrestrial and marine phenomena. Approximately 16% of the total area of continental earth is potentially involved in groundwater salinisation. Seawater intrusion can be considered to be the primary phenomenon for study in terms of groundwater salinisation. There are different measures, actions and practices for managing groundwater when the natural resource is exposed to salinisation. Some of these measures have a mitigation objective. Other measures have a more adaptive approach and accept the high groundwater salinity but adjusting the groundwater use so that it is not harmful. On the basis of worldwide experiences, three different approaches to the protection of groundwater via salinisation mitigation and/or groundwater salinity improvement can be recognised considering the classifications of the salinisation sources and focusing on the effect of seawater intrusion. The paper describes approaches. The complexity of these approaches generally increases due to difficulties caused by groundwater quality and quantity degradation and increased demand for quality water. Moving from the lowest to the highest complexity, these approaches are the engineering approach, the discharge management approach, and the water and land management approach. The engineering approach is realised on the local scale with the purpose of controlling the salinisation, optimising the well discharge with specific technical solutions and/or completing works to improve the quality and/or quantity of the discharged fresh groundwater. The discharge management approach includes a coastal aquifer and defines rules concerning groundwater utilisation and well discharge. The water and land management approach should be applied on the regional scale. This approach becomes necessary when one or more need creates an overall framework of high-quality water scarcity. These conditions, sometimes combined with an awareness of negative environmental effects, force people to accept new water saving practices and land use modifications. As the natural effects of salinisation can be enhanced by a multiplicity of human actions, the discharge management approach and the water and land management approach should generally be applied by water authorities or institutional and governmental organisations that are responsible for groundwater quality and availability.

The coastal carbonate Apulian aquifers, located in southern Italy, feed numerous coastal cold springs and constitute the main local source of high quality water. The group of Santa Cesarea springs constitutes the unique occurrence of thermal groundwater outflow, observed in partially submerged coastal caves. The spring water is rich of hydrogen sulfide; temperature ranges from 25 to 33 C°. For their properties, spring waters are used for spa activities from several decades. Hydrogeological spring conceptualisations proposed up now were not able to justify water geochemical peculiarities or were not completely confirmed up now. To reduce these uncertainties, a complex hydrogeological survey has been defined. Geological and structural surveys, chemical and isotopic groundwater analyses, spring and well discharge measurements, well loggings, multi-parameters spring automatized measurements, and cave explorations are ongoing. All available data have been used to improve the knowledge of groundwater flow system, including the valuable deep aquifer, the origin of the thermal waters, and to investigate the possibility of using low-enthalpy geothermal fluids to fulfil the thermal needs of the town of Santa Cesarea Terme.

The coastal carbonate Apulian aquifers, located in southern Italy, feed numerous coastal cold springs and constitute the main local source of high quality water. The group of Santa Cesarea springs constitutes the unique occurrence of thermal groundwater outflow, observed in partially submerged coastal caves. The spring water is rich of hydrogen sulfide; temperature ranges from 25 to 33 C°. For their properties, spring waters are used for spa activities from several decades. Hydrogeological spring conceptualisations proposed up now were not able to justify water geochemical peculiarities or were not completely confirmed up now. To reduce these uncertainties, a complex hydrogeological survey has been defined. Geological and structural surveys, chemical and isotopic groundwater analyses, spring and well discharge measurements, well loggings, multi-parameters spring automatized measurements, and cave explorations are ongoing. All available data have been used to improve the knowledge of groundwater flow system, including the valuable deep aquifer, the origin of the thermal waters, and to investigate the possibility of using low-enthalpy geothermal fluids to fulfil the thermal needs of the town of Santa Cesarea Terme.

Hypogenic caves, developed by sulphuric acid speleogenesis, are known all over the world among which the Santa Cesarea Terme caves have been included. They are four submerged caves, located along a coastal carbonate sector in Southern Italy and hosting the outflow of coastal springs of thermal mixed waters (from 21 to 33 °C). These waters derive from the mixing of three water end members: the fresh pure groundwater of a wide karstic aquifer, the deep sulphur thermal water and the seawater. This cave system represents an almost unique case of hypogenic sea caves in carbonate environment. The thermal mixed waters have a different effect on the surrounding rocks of the caves, influencing the sulphuric acid speleogenetic process within the whole cave system. To understand the complex and overlapping natural processes acting on the developmentof these coastal caves, a multidisciplinary study has been carried out. This study has integrated all the data resulting from different methods and technologies, merging morphology, structural geology, hydrogeology, hydrogeochemistry and mineralogy. This multidisciplinary study has allowed to define the main geochemical processes acting within these caves, including the cave development and the formation of the mineral concretions. After the introduction of H2S in the thermal waters, formed by the reduction of sulphates in the sedimentary deposits crossed at depth in the offshore, the oxidation occurs within the caves, producing sulphuric acid. Favoured by upwelling deep-seated thermal flows, this acid dissolves the limestone, with condensation corrosion process that involve replacement of limestone rock with gypsum. This process has resulted to be more active and remarkable within the Gattulla Cave, one of the Santa Cesarea Terme sea caves.

The Mar Piccolo (literally "narrow sea"), a sea internal basin which is part of the Taranto Gulf, located along the Ionian coast in southern Italy (Apulia region), represents both a peculiar and sensitive environmental area and a national environmental and social emergency due to the level of sea water pollution due to the pollutants coming from the close industrial area of Taranto.The area, located between the southern part of the Murgia plateau and the Ionian sea, is geologically characterized by a sequence of Mesozoic limestone (the Apulian carbonate platform) constituting the foreland of the southern Apennines chain. The Mesozoic sequence is intensely fissured and karstified, and forms an important groundwater reservoir.The aquifer occurring in the carbonate sequence of the Murgia plateau feeds numerous coastal springs and constitute the main local source of pure fresh groundwater. Galeso, Battentieri and Riso are the main subaerial springs located along the coast of Mar Piccolo, not far from the town of Taranto. This area is also characterized by several submarine springs, locally called "Citri".Submarine freshwater discharge plays an important, though not well quantified, role in the hydrogeological equilibrium of the system, but also the source of the spreading of many pollutants in the Mar Piccolo area due to the close presence of one of the largest European steel mill together a number of hazardous industrial activities of other types.The paper describes the efforts and the preliminary results to define a detailed conceptualisation of the aquifer as main support to characterise the hydrological balance of the internal sea and the quality of sea water and the effect on of the ecological equilibrium of the coastal environment.

The Cesine Wetland, located along the Adriatic coast, was recognized as a Wetland of International Interest and a National Natural Park. Managed by the "WorldWide Fund for nature" (WWF), it is considered a groundwater dependent ecosystem which is affected by seawater intrusion. The site was selected to test the environmental compatibility of a low-enthalpy geothermal power plant (closed loop) operating in the aquifer saturated portion with purpose to improving the visitor centre. For this purpose, the long-lasting thermal impact on groundwater was assessed using a multi-methodological approach. The complex aquifer system was carefully studied with geological, hydrogeological and geochemical surveys, including chemical and isotopic laboratory analyses of surface water, groundwater and seawater. The isotopes 18O, D, 11B, and 3H were useful to clarify the recharge contribution, the water mixing and the water age. All information was used to improve the conceptualization of the water system, including aquifers and the boundary conditions for a density driven numerical groundwater model. The purpose was to forecast anthropogenic thermal groundwater variations up to 10 years of plant working before the plant realization and to validate the solution after some working years. All results show the environmental compatibility notwithstanding the peculiar ecological environment.

The Cesine Wetland represents one of the most valuable wetlands of Apulia. It is located in Salento, along the Adriatic coast, not far from Lecce. It was recognized as "wetland of international interest"; it became "state natural reserve" and since 1980 it is managed by the "World Wide Fund for nature" (WWF). The protected area, 620 hectares wide, is shaped as a narrow and elongated strip that follows the coastline. It is crossed by numerous artificial channels, some of which represents the inland boundary. The core of the reserve, the eastern sector, includes the brackish water marshes, wooded areas and those of the Mediterranean marquis that give hospitality to the major habitats of community interest. The environmental peculiarities of the Cesine Wetland are due to a complex hydrogeological pattern, the high contribution of groundwater outflow, and to a peculiar dynamic equilibrium with sea, also due to the role of the wide coastal aquifer of Salento. The western part hosts the reclaim activities, where the ancient rural building "Masseria Cesine", used as the wetland visit center. This visit center site was selected for the construction of a low-enthalpy geothermal power plant as part of a pilot project funded by the EU IPA Legend 2007-2013 Adriatic. The pilot plant is a case perhaps unique in a protected wetland, made to check the replicability of geothermal air conditioning systems in environmentally valuable contexts. It was designed and realized for the monitoring of the environmental effects of heat exchange. The geothermal heat pump system consists of two double U-shaped geothermal probes, 200 meters deep, intercepting three aquifers separated by aquiclude levels with different hydraulic and hydrogeochemical characteristics. Piezometric boreholes were realized at different depths and different distances from the system, allowing the estimation of several parameters or measurements of physical variables, including temperature. Hydrogeological conceptualization and periodic measurements support the implementation of a numerical model, designed for future assessment of environmental effects. The heat transport numerical model was developed in FEFLOW, in order to estimate the extension of the thermal plume generated within the aquifers after a long period of heat exchange. The numerical model was developed assigning different values of hydraulic, thermal and geochemical properties to each layer, considering in particular saline concentration of groundwater. The model parameters definition was based on thermal properties of ground samples, Ground Response Test (GRT), groundwater level measurements, temperature logs and groundwater surveys. Initial simulation results contributed to the evaluation of geothermal plant influence on groundwater, a fundamental resource ensuring the existence of wetlands and autochthonous plant and animal species, and confirmed the sustainability characteristics of the heat pump system.

The Ugento Wetland, recognized as a Site of Community Importance (SCI, European Directive 92/43/CEE) from 2005, is a "Regional natural littoral Park" from 2007, located along the Ionian coast, in south-eastern part of Salento (Apulia region). The environmental peculiarities of the Ugento Wetland are due to a complex hydrogeological pattern, the high contribution of groundwater outflow, and to a peculiar dynamic equilibrium with sea, also due to the role of the wide coastal aquifer of Salento. The main objectives of the present research are the definition of the hydrogeological conceptualisation to create a basic knowledge of the physical environment, to be used as a basis for the design of effective management policies of water resources to safeguard the ecological and environmental equilibria, considering the relevant impact of anthropogenic activities. In this area, the human pressure on water resources was detected in terms of surface water pollution, probably due to illegal dumps and the use of fertilizers and nitrogen compound for agricultural purposes, which is the origin of an exponential growth of the floating macro-algae mass in basins. As a consequence, some event of eutrophication triggers the algal growth, the effect of which is the sharp reduction, almost to zero, of the surface water velocity, up to, in some cases, to a widespread fish mortality. Apart from water pollution effects, during the dry season, due to the increase of groundwater discharge, the sharp piezometric decline improves the effects of seawater intrusion on groundwater. A geological and hydrogeological survey and study were realised and merged with the characterisation of the land use modifications back to the fifties. The attention was focused on the analysis of the complex hydrogeological characteristics, which is due to the overlapped effects of shallow and deep aquifers and of their outflow along the coastal area. The focal role of the shallow aquifer, which is predominant and extremely importance for the hydrological balance and so for the ecological equilibria, a specific monitoring groundwater network of quantitative and qualitative parameters was implemented. The merging of hydrogeological factors and anthropogenic modifications was discussed using indicators. Two main macro-indicators, water and soil, were selected. The critical issues related to the management of human activities potentially dangerous for the wetland environment, was considered with the definition of guidelines for their mitigation, based on the discussion of the indicators.