Papers by Maria Dolores Fidelibus
Environmental Earth Sciences , 2021
Many buried karst areas in Iran, and in other parts of the world have not yet been mapped using d... more Many buried karst areas in Iran, and in other parts of the world have not yet been mapped using detailed geological or geophysical studies to delineate susceptibility to sinkhole development. The purpose of this paper is to investigate the possibility of using the results of hydrogeochemical analysis with routine measurements of physicochemical parameters to evaluate and detect areas prone to sinkhole develop. Sixteen spatial maps were prepared using analyzed data from 77 water samples from monitoring water wells in the Kabudar Ahang, Razan, and Qahavand (KRQ) sub-catchments of the Hamadan province, western Iran. By use of geographic information system tools 16 thematic maps for physicochemical parameters (EC, pH., TDS, and groundwater temperature), major cations (Ca 2+ , Mg 2+ , Na + , and K +), anions (HCO-3 , SO 4 2-, NO 3-, and Cl-), and calcite, dolomite, gypsum, and partial pressure of CO 2 saturation indices (SIC, SID, SIG, and SIpCO 2) were prepared. It was hypothesized that the anomalies of each parameter concentration could be consistent with sinkhole prone areas. To evaluate this assumption, the area under the Receiver Operating Characteristic (ROC) curve was calculated by 100 points as a true sinkhole pixel (50 positive true) and non-sinkhole point (50 true negative). The areas under curve of ROC for these thematic maps were calculated for the 16 variables. Results show that the dolomite and calcite saturation indices (0.49 and 0.43, respectively) are poor indicators, whereas HCO-3 and pCO 2 saturation indexes (0.83 and 0.78, respectively) are good indicators of sinkhole susceptibility in the study area. The result confirmed application of hydrogeochemical anomaly analyses and the ROC validation method in covered karst can be a useful tool for prediction of sinkhole prone zones forming in region, where sparse data are available.
Hydroinformatics, 2022
Daily precipitation and groundwater level data, registered at 7 rain gauge stations and 11 monito... more Daily precipitation and groundwater level data, registered at 7 rain gauge stations and 11 monitoring wells in the Salento coastal karst aquifer (Southern Italy) were subject to short time series analyses to evaluate the hydrodynamic response of the aquifer. Results show that the Salento karst system has in general great storage capacity, which suggests a poor degree of aquifer karstification, and dominance in the permeability structure of not well-developed hierarchical karst networks. Baseflow generally dominates on quick flow, which only occasionally occurs. The dominant hydraulic behaviour is unimodal baseflow with a bimodal baseflow and quick flow one from time to time. Some local specific features, which emerge depending on the rainfall frequency and depth, and the geological and structural characteristics, point out that some components of the permeability structure, as the epikarst and major faults, only activate depending on the characteristics of the input. The study is novel because the analyses concerned specific sets of hydrological years from 2007 to 2011; also, because the analysis was conducted for a coastal karst aquifer of significant size, characterized by a regional groundwater flow system with an unsteady lower boundary, without inland freshwater springs, and significant exploitation by wells.
Science of the Total Environment, 2022
Statistical and geochemical methods validate each other, showing comparable results. • Both metho... more Statistical and geochemical methods validate each other, showing comparable results. • Both methods outline recharge areas and those subject to salinization processes. • The proposed approach enabled to outline areas with different salinization dynamics. • The integrated methodology was used to create groundwater salinization hazard maps.
Sustainability, 2022
Salento is a regional coastal karst aquifer located in Southern Italy with a highly complex geolo... more Salento is a regional coastal karst aquifer located in Southern Italy with a highly complex geological, geomorphological, and hydrogeological structure. High and unruly exploitation of groundwater from licensed and unlicensed wells for irrigation and drinking purposes affects groundwater, with consequent degradation of its qualitative and quantitative status. The increased frequency of meteorological droughts and rising temperatures may only worsen the already compromised situation. The absence of complete and enduring monitoring of groundwater levels prevents the application of some methodologies, which require long time series. The analysis of climate indexes to describe the groundwater level variation is a possible approach under data scarcity. However, this approach may not be obvious for complex aquifers (in terms of scale, intrinsic properties, and boundary conditions) where the response of the groundwater to precipitation is not necessarily linear. Thus, the proposed research deals with the assessment of the response of the Salento aquifer to precipitation variability based on correlations between the Standardized Precipitation Index (SPI) and Standardized Precipitation and Evapotranspiration Index (SPEI) and groundwater levels for nine monitoring wells from July 2007 to December 2011. The study aims at evaluating the ability of the above indicators to explain the behavior of groundwater on complex aquifers. Moreover, it has the general aim to verify their more general reliable application. Results of three different correlation factors outline direct and statistically significant correlations between the time series. They describe the Salento aquifer as a slow filter, with a notable inertial behavior in response to meteorological events. The SPI 18-months demonstrates to be a viable candidate to predict the groundwater response to precipitation variability for the Salento aquifer.
Journal of Hydrology, 2025
Seawater intrusion is the primary cause of groundwater salinisation in coastal aquifers. However,... more Seawater intrusion is the primary cause of groundwater salinisation in coastal aquifers. However, attributing salinisation solely to seawater intrusion may not always be accurate, given the likely presence of other sources. To understand if salinisation comes from seawater intrusion and its onset is crucial for groundwater management, but there are no definite threshold values for common indicators such as chlorides. Based on 1662 groundwater analyses from five Mediterranean coastal aquifers, the study aimed to distinguish the effects of mixing with present-day seawater from those caused by other sources. The trend analysis of cumulative probability plots of chloride (and total dissolved solids) is a key method for discriminating different groundwater salinisation sources and processes. Results establish that chloride, as a non-reactive tracer, is a more reliable indicator of seawater intrusion than total dissolved solids, a reactive indicator.
A chloride concentration threshold of 200 mg/L identifies the seawater intrusion onset. The threshold validation comes from groundwater salinisation facies, as provided by groundwater-type codification.
Fresh groundwater (Cl < 200 mg/L) anomalous total dissolved solids highlight the input of non-chloride salts and pollutants, providing caution regarding using total dissolved solids to recognise seawater intrusion. Beyond the threshold (Cl > 200 mg/L), data disclose emergent signals of salinisation sources and water–rock interaction processes overlapping seawater intrusion or the involvement of saline fluids different from present-day seawater. The threshold and a new categorisation of groundwater in coastal aquifers according to salinisation processes provide a benchmark for identifying and managing seawater intrusion in the Mediterranean area.
Scientific Reports , 2024
Water pollution is a significant issue resulting from past long-term actions. The remediation pro... more Water pollution is a significant issue resulting from past long-term actions. The remediation projects carried out under law constraints for industrial plants, which have been the major contributors to environmental and water pollution, are currently providing a significant amount of data about contaminated soil, surface waters, and groundwater. Most of such plants worldwide are in coastal zones. Based on a significant amount of chemical and environmental data for a coastal contaminated site subject to variable groundwater salinization, this study aimed to understand the mobility of some trace elements because of coastal zone dynamics. Data concerned 688 groundwater samples, including As, Hg, Cd, Cr tot , Cu, Ni, Pb, V, Se, Zn, pH, electrical conductivity, chlorides, total organic carbon and organic contaminants as quantitative variables, enhanced by additional qualitative variables such as groundwater salinity, season, water level, precipitation, and industrial activity type to make the dataset as representative as possible of the site under investigation. The study used robust multivariate statistical analyses to analyse the complex dataset and explain the relevant factors influencing contaminant behaviour under different environmental conditions. The Multivariate Statistical Analysis distinguished three clusters of trace elements with diverse reactivity to changes in groundwater salinization. The first includes Se, Cu, Cr tot , V, and Ni, showing the highest correlation with electrical conductivity and chlorides because of their high affinity to form chloride or organic chloride complexes and for ion competition. Zn and Pb cluster in the second group: they are less reactive to groundwater salinization and more influenced by cation and anion competition and organic matter. The mobility of Hg and As (third cluster) significantly correlates with Fe and Mn, underlining the dominant role of reductive dissolution of trace elements-bearing minerals (Fe/Mn/Al-oxy-hydroxides) and metal-organic complexes. The correlation between the clustering of variables in groundwater and soils shows the influence of sediment structure, mineral composition, and physical and chemical soil conditions on the distribution in soils of trace elements and their transport to groundwater. The study proposes a valuable approach for assessing the effects of salinization in contaminated coastal aquifers. It supports planning multipurpose characterization and monitoring campaigns of contaminated coastal sites and provides guidance on the correct associated remediation projects.
Water
Machine learning (ML) algorithms are extensively used with outstanding prediction accuracy. Howev... more Machine learning (ML) algorithms are extensively used with outstanding prediction accuracy. However, in some cases, their overfitting capabilities, along with inadvertent biases, might produce overly optimistic results. Spatial data are a special kind of data that could introduce biases to ML due to their intrinsic spatial autocorrelation. To address this issue, a special resampling method has emerged called spatial cross-validation (SCV). The purpose of this study was to evaluate the performance of SCV compared with conventional random cross-validation (CCV) used in most ML studies. Multiple ML models were created with CCV and SCV to predict groundwater electrical conductivity (EC) with data (A) from Rhodope, Greece, in the summer of 2020; (B) from the same area but at a different time (summer 2019); and (C) from a new area (the Salento peninsula, Italy). The results showed that the SCV provides ML models with superior generalization capabilities and, hence, better prediction resul...
Goldschmidt2022 abstracts, 2022
Proceedings of the 8th Salt Water Intrusion Meeting, Bari, Italy. GEOLOGIA APPLICATA E IDROGEOLOGIA , 1983
Hydrogeochemical surveys were carried out on coastal springs and wells drawing waters from the de... more Hydrogeochemical surveys were carried out on coastal springs and wells drawing waters from the deep aquifer throughout Apulian region from the Gargano to the Salentine Peninsula. Analyses of the main constituents as well as a numerous series of minor constituents were conducted on each water sample. From a geochemical point of view some groundwaters show a calciummagnesium-bicarbonate chemism being peculiar to the leaching of sedimentary formations. Springs show a sodium-chloride, calcium-sulphate chemism according to the mixing processes with sea water. Meaningful correlations between Li, B and Cl were found, thus allowing a classification of all examined waters in three distinct groups. Their different characteristics, on the other hand, are in agreement with the different hydrogeological situations within an aquifer mostly homogeneous from the lithological standpoint. The main differentiation reason of Li and B behaviour versus Cl content seems to be dependent upon a different age of intruding sea water. Furthermore Ra and Rn contents of examined waters are considered related to Cl content.
IV° Conv. Int. di Geoingegneria, "Difesa e valorizzazione del suolo e degli acquiferi, 1994
&amp;amp;lt;p&amp;amp;gt;The Bradanic Trough (Southern Italy) is the Pliocene-present-day... more &amp;amp;lt;p&amp;amp;gt;The Bradanic Trough (Southern Italy) is the Pliocene-present-day south Apennines foredeep. It is filled by a thick Pliocene to Pleistocene sedimentary succession constituted by hemipelagites (Blue Clay Fm.) in the lower part, and coarse grained deposits (sands and conglomerates) in the upper part, shaped in marine or continental terraced environment.&amp;amp;lt;/p&amp;amp;gt;&amp;amp;lt;p&amp;amp;gt;On the eastern border of the Bradanic Trough along the Murgian Plateau (Apulia, Italy) numerous morphological lineaments are associated with sequential lowering and rotation of the surface, aligned with the carbonate substrate dip direction.&amp;amp;lt;/p&amp;amp;gt;&amp;amp;lt;p&amp;amp;gt;These morphologies have been interpreted so far as erosion products; their association with medium-deep water circulations and surface phenomena, like mud volcanoes, now allows their interpretation as a lumped mass, detached and tilted along shear surfaces.&amp;amp;lt;/p&amp;amp;gt;&amp;amp;lt;p&amp;amp;gt;The surface patterns of such surfaces may be easily detected for the presence, at some distance, of a quite similar twin track, which overlaps with good agreement.&amp;amp;lt;/p&amp;amp;gt;&amp;amp;lt;p&amp;amp;gt;The numerical analysis of the tracks extracted from accurate DTMs allows us to reconstruct the kinematic patterns of the tectonic displacement (distance of the detachment; rotation; angle of the shear plane). This type of analysis might reveal very useful in some fields of engineering geology, such as underground works, and for interpreting many hydrogeological phenomena within the study area. Finally, the correct 3D representation of the detached masses helps to identify the true causes of the direct faulting, which is not always linked to the tectonics, not active in the concerned regions.&amp;amp;lt;/p&amp;amp;gt;
IX Convegno Nazionale di Speleologia in Cavità Artificiali, 2020
III° Convegno dei Giovani Ricercatori in Geologia Applicata, 1993
Salt water intrusion meeting. 9, 1986
Physical extremes can be distinguished in "sudden physical extremes" (e.g. earthquakes, tsunami) ... more Physical extremes can be distinguished in "sudden physical extremes" (e.g. earthquakes, tsunami) and "progressive physical extremes" (e.g. drought, desertification, landslides). They differ for frequency, intensity, spatial extent, duration and timing of occurrence. If a physical extreme, by interacting with human systems, induces negative consequences, its outcome can be a "disaster". The disasters are, in both above cases, characterized by a few phases: physical extreme occurrence, emergency, response, and recovery. However, in the case of a progressive physical extreme, the disaster develops with an overlap in the time of the above-mentioned phases. When the events are repetitive, the emergency planning (which follows a cycle) succeeds with preparedness and mitigation with the intent of reducing the risk. Both the sudden and progressive physical extremes produce cascading effects of consequences on social, environmental and economic systems. Disasters consequent to sudden and progressive extremes show, however, some differences, mainly attributable to the "visibility" of the effects and to their time scale of evolution. As matter of fact, a disaster consequent to a progressive physical extreme produces "emerging signals" that are often invisible. Moreover, the emergency phase can arise with a time delay compared to the occurrence of the physical extreme, depending on the spatial scale of impacted system. The above differences allow defining "creeping disasters" the potential disasters related to progressive physical extremes. This study deals with some peculiar "cascading disasters" consequent to drought, which is the main "creeping disaster", namely the groundwater drought and the consequent salinization of coastal aquifers. In regional flow systems, their effects are invisible in the immediate to common people (and often even to managers) because of the concealed nature of groundwater; moreover, they are difficult to assess because of the shift over time of their evolution compared to the promptness of surface effects. The study area is the Salento coastal karstic aquifer (Apulia region, Southern Italy), where the groundwater flows according to a regional flow system. It has been subject to successive meteorological droughts between 1960 and 2010. The groundwater monitoring performed during this period, even with some gaps, allows identifying time lags between superficial effects and underground system response, potential tipping points, and emerging signals of the cascading disasters.
The EGU General Assembly, 2005
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Papers by Maria Dolores Fidelibus
A chloride concentration threshold of 200 mg/L identifies the seawater intrusion onset. The threshold validation comes from groundwater salinisation facies, as provided by groundwater-type codification.
Fresh groundwater (Cl < 200 mg/L) anomalous total dissolved solids highlight the input of non-chloride salts and pollutants, providing caution regarding using total dissolved solids to recognise seawater intrusion. Beyond the threshold (Cl > 200 mg/L), data disclose emergent signals of salinisation sources and water–rock interaction processes overlapping seawater intrusion or the involvement of saline fluids different from present-day seawater. The threshold and a new categorisation of groundwater in coastal aquifers according to salinisation processes provide a benchmark for identifying and managing seawater intrusion in the Mediterranean area.
A chloride concentration threshold of 200 mg/L identifies the seawater intrusion onset. The threshold validation comes from groundwater salinisation facies, as provided by groundwater-type codification.
Fresh groundwater (Cl < 200 mg/L) anomalous total dissolved solids highlight the input of non-chloride salts and pollutants, providing caution regarding using total dissolved solids to recognise seawater intrusion. Beyond the threshold (Cl > 200 mg/L), data disclose emergent signals of salinisation sources and water–rock interaction processes overlapping seawater intrusion or the involvement of saline fluids different from present-day seawater. The threshold and a new categorisation of groundwater in coastal aquifers according to salinisation processes provide a benchmark for identifying and managing seawater intrusion in the Mediterranean area.