Hydrogeological Characteristics Research Articles

Sources and Transformation of Nitrate in Shallow Groundwater in the Three Gorges Reservoir Area: Hydrogeochemistry and Isotopes

Nitrate is among the most widely occurring contaminants in groundwater on a global scale, posing a serious threat to drinking water supplies. With the advancement of urbanization and mountainous agriculture, the nitrate in the groundwater of Wanzhou District in the Three Gorges Reservoir Area has formed a complex combination of pollution sources. To more accurately identify the sources of nitrate in groundwater, this study integrates hydrochemical methods and environmental isotope techniques to analyze the sources and transformation processes in shallow groundwater nitrate under different land-use types. Furthermore, the Bayesian isotope mixing model (MixSAIR) is employed to calculate the contribution rates in various nitrate sources. The results indicate that nitrate is the primary form of inorganic nitrogen in shallow groundwater within the study area, with nitrate concentrations in cultivated groundwater generally higher than those in construction land and forest land. The transformation process of nitrate is predominantly nitrification, with little to no denitrification observed. In cultivated shallow groundwater, nitrate mainly originates from chemical fertilizers (36.3%), sewage and manure (35.4%), and soil organic nitrogen (24.7%); in forested areas, nitrate primarily comes from atmospheric precipitation (35.3%), chemical fertilizers (31.3%), and soil organic nitrogen (22.1%); while in constructed areas, nitrate mainly derives from chemical fertilizers (46.0%) and sewage and manure (32.2%). These results establish a scientific foundation for formulating groundwater pollution control and management strategies in the region and serve as a reference for identifying nitrate sources in groundwater in regions with comparable hydrogeological features and pollution profiles.

Application of Hydrological and Hydrogeological Models for Evaluating Groundwater Budget in a Shallow Aquifer in a Semi-Arid Region Under Three Pumping Rate Scenarios (Tavoliere di Puglia, Italy)

We analyze the variation in groundwater budget by modeling an aquifer in a semi-arid region in southern Italy, using different good pumping scenarios. This aquifer is overexploited due to the agricultural vocation of the area. We propose an integrated method to assess the distribution of hydrogeological parameters and the recharge rates. The hydrogeological parametrization is performed through a hydrostratigraphic approach using the geostatistical tool. Recharge rates are computed through a soil water balance application, using different monitoring stations over the area for the whole period of interest. Integrating the results of this analysis with pumping scenarios based on the water irrigation requirement of the main crops in the area, different water budgets are estimated. The results show how different pumping scenarios affect the availability of water resources and thus underline the importance of management. This integrated hydrogeological model can be applied to other areas with similar hydrogeological characteristics, and it can be considered a valuable tool for evaluating sustainable groundwater management strategies, considering land use practices and socio-economic factors.

Assessment of surface and groundwater quality in the Ctalamochita River basin, Argentina: hydrogeochemical characteristics and exploratory data analysis.

Freshwater and groundwater are important resources for the drinking water supporting agricultural and livestock activities in the Córdoba province, Argentina. The aim of this study was to assess the physicochemical and microbiological quality of surface water (n = 14) and groundwater (n = 17) sites in the middle-lower basin of the Ctalamochita River (Córdoba, Argentina) for human and animal consumption. A total of 18 physicochemical and five microbiological parameters were evaluated to determine the hydrogeological characteristics of both water resources and their suitability for human and animal consumption using the Water Quality Index (WQI). The results indicated that Na+ and HCO3- were the dominant cation and anion, respectively, in both water resources. Physicochemical and microbiological parameters values were compared with national and international guidelines. The WQI showed that groundwater samples exhibited poorer quality when compared to surface waters for human consumption, primarily due to elevated concentrations of major ions and the presence of total coliforms and Pseudomonas aeruginosa. Meanwhile, the WQI for animal consumption indicated that both surface and groundwater samples were suitable for this purpose. The Piper diagram showed that most of the surface water samples were classified as Na+-Cl--HCO3-, while groundwater samples were classified as Na+-HCO3-. This classification highlights the hydrogeochemical differences between the two water resources. TheGibbs diagram indicates that the chemical composition of both surface and groundwater sources is primarily controlled by processes of rock-water interaction and evaporation. The findings of this study will facilitate the development of a proactive plan to safeguard and sustain water resources in the middle-lower basin of the Ctalamochita River. This can be achieved through the implementation of preventive strategies and the introduction of innovative policies.

Controls on regional sulphate distribution in shallow groundwater in the western Canadian Interior Plains

Sulphate (SO4), predominantly derived from sulphur (S)-bearing glacial sediments distributed widely across the Canadian Interior Plains, contributes to high groundwater salinity and can be detrimental to riparian and dry-land ecosystems, agricultural production, and water use. While previous researchers investigated SO4 distribution and dynamics in shallow groundwater at local scales (<1500 km2), we examine SO4 occurrence in groundwater at larger scales, and to depths of ∼150 m, considering variations in geology, glacial history, climate, and geochemical and hydrogeological settings in the Canadian province of Alberta. Sulphate concentrations in groundwater vary considerably, with 15 % of 139,130 samples above the 500 mg/L Canadian drinking water aesthetic objective. Analysis of δ34SSO4 and δ18OSO4 from 179 wells throughout Alberta shows SO4 is dominantly derived from oxidation of S-bearing material. At this large scale, marine shale bedrock subcrops, glacial ice flow directions, and climate control SO4 distribution. Groundwater contains less SO4 (<200 mg/L) in western Alberta compared to the east due to a lack of S-bearing bedrock, higher groundwater recharge rates, thinner glacial sediments, and increased groundwater circulation. Focusing on a region in south-central Alberta (Red Deer area), hydrogeological characteristics relating to SO4 formation, recharge, permeability, hydraulic gradient, and travel time are included in a principal component analysis to identify six groundwater groups at varying stages of evolution and SO4 concentrations depending on their hydrogeological setting. Low SO4 concentrations are associated with areas of high recharge, where SO4 has been leached from the sediments, or with more evolved bedrock groundwater where SO4 has been reduced or was recharged in pre-glacial times. High SO4 concentrations are found in areas of lower recharge and permeability, where flushing occurs more slowly. Combining the Red Deer area and province-wide analyses, we identify seven regions across Alberta with characteristic distribution and controls on SO4 occurrence in shallow groundwater.

Groundwater Dynamics in the Middle Brahmaputra River Basin: A Case Study of Shallow Aquifers in Inner Guwahati City, Assam, India

This study investigated the hydrogeological characteristics and groundwater dynamics in the shallow aquifer zones of inner Guwahati city, Assam, India. Sixteen dug wells spread across the city, specifically used for domestic purposes, were selected for this study. Additionally, ten wells were selected for trend analysis. The borehole lithology reveals predominant compositions of clay, sand, and granules, with thin clay cappings indicating significant groundwater potential. Depth-to-water level analysis revealed varying water levels across the study area, with shallow levels in the northern and western regions and gradual deepening toward the eastern and southern parts. The groundwater flow directions show nonuniform patterns and reflect the influence of topography and domestic pumping in urban residential zones. The general groundwater flow direction is toward the Brahmaputra River. Trends in groundwater level, assessed using the Mann–Kendall test and Sen’s slope, suggest both falling and rising trends across different locations, indicating complex groundwater dynamics influenced by factors such as recharge, extraction, and topography. However, the long-term rainfall data indicate no significant trend over the studied period, suggesting limited natural influence on groundwater level trends. These findings may contribute to a comprehensive understanding of groundwater dynamics in the study area and are essential for sustainable water resource management and mitigation of groundwater depletion risks.

HYDRO GEOPHYSICAL INVESTIGATION FOR GROUND SOURCE HEAT PUMP SYSTEM INSTALLATION IN SEMI-ARID REGION OF CAMEROUN

Hydrogeophysical parameters of the ground play a vital role in heat transfer of ground source heat pump (GSHP) systems. Then, the investigation of the ground is necessary for the design and planning of GSHPs. This paper deals with investigations of Hydrogeophysical parameters of GSHP systems in Cameroon. Eighty-four drillings with the average deep of forty-seven meters have been performed in the Far North region of Cameroun in order to get hydrogeological and hydro geophysical characteristics of ground for shallow energy utilization. The results of geological study, vertical electrical sounding, pumping test, thermophysical properties, groundwater property and well data could help to understand better the heat transfer of borehole heat exchanger (BHE) and geo localization of potential GSHP in residentials of Logone et Chari, Cameroon. Closed systems of GSHP could be installed in the study area.

Saltwater intrusion simulations in coastal karstic aquifers related to climate change scenarios

Coastal zones are crucial ecosystems supporting significant biodiversity and pertinent socio-economic activities. However, anthropogenic development contributes to socio-environmental complexities, particularly public water supply threats caused by climate change. This research presents a case study on the north-western coast of Yucatan, Mexico, which models potential saltwater intrusion in groundwater for multiple projections of sea level rise and recharge change due to climate change and its implications for the public water supply of the regional population and ecosystem. For this purpose, a previously calibrated and validated numerical model is employed, adapting its boundary conditions, keeping its calibrated hydrogeologic parameters, and considering the 2040 and 2100 climate change projections. Simulation results show that under these projections, significant saltwater intrusion may occur, reducing freshwater thickness due to increased salinity in groundwater and a loss of freshwater sources resulting from brackish-saline wedge intrusion. These scenarios are of particular concern as freshwater in this coastal region is the main source for public water supply and for freshwater input in coastal ecosystems. Moreover, this study underscores the susceptibility of karstic aquifers to salinization, especially in the face of rising sea levels, given their unique hydrogeological characteristics and substantial responsiveness to marine forcings. In spite of the uncertainties in global climate change predictions, this study enhances our understanding of the dynamics of these unique aquifers, and presents future saltwater intrusion projections that offer valuable technical insights to design and implement pertinent and resilient coastal aquifer management strategies.

Influence of Chemical Weathering and Microcracks on Permeability Variations in Crystalline Rocks

Rock permeability, an important factor in subsurface fluid migration, can be influenced by microcracks and chemical weathering due to water–rock interactions. Understanding the relationship between permeability, chemical weathering, and microcracks is crucial for assessing fluid flow in rocks. This study focuses on the hydrogeological characteristics of granite and gneiss, potential host rocks for high-level radioactive waste disposal in South Korea. Samples were analyzed for permeability, porosity, P-wave velocity, and chemical weathering indices. Regression analysis revealed a weak correlation between permeability and both porosity and rock density, while an inverse correlation was observed between permeability and chemical weathering indices. Interestingly, some samples showed low permeability (10−21 to 10−22 m2) despite high weathering, while others showed high permeability (10−18 to 10−19 m2) despite low weathering. SEM-EDS analysis indicated the presence of microcracks within the rocks or the filling of these cracks with secondary minerals. The findings suggest that chemical weathering generally increases pore size and porosity, but actual permeability can vary depending on the presence and connectivity of microcracks and the extent to which they are filled with secondary minerals. Therefore, both chemical weathering and microcrack connectivity must be considered when evaluating the hydrogeological characteristics of crystalline rocks.

Enhancing water management in Northern European lowland chalk streams: A parsimonious, high-resolution hydrological model using groundwater level as a proxy for baseflow

Study regionThe River Frome, a chalk stream in West Dorset, UK. Study focusHigh-resolution hydrological models are required to integrate with the current wave of high-frequency data and advance our understanding of pollutant sources, pathways, and sinks. This presents several challenges in chalk streams, as their high-permeability and unique hydrogeological characteristics often leads to complex models that are overparameterized and computationally burdensome. In this article, we develop a novel and parsimonious modelling approach to describe the surface hydrology for a chalk stream in high resolution (15-minute frequency, ≤ 100 m cross-section spacing), using groundwater levels as a proxy for spring discharges. New hydrological insights for the regionOur results show that chalk stream dry-weather flows can be simulated accurately and parsimoniously at high-resolution (Nash-Sutcliffe efficiency = 0.97, mean relative error = 2.86 %, for a five-year period). We also show that spring discharges are the dominant form of flow accretion in all seasons and are critical to dilute sewage treatment inputs during the ecological growing season, whilst runoff and quick-flow pathways in the river valley corridor contribute a small proportion to annual flow accretion (< 5.2 %). Due to its simplicity and few parameters to calibrate, this modelling approach has broad applicability in lowland permeable catchments. Management implications include expeditious investigations of high-resolution freshwater quality responses to pollution and informing abstraction limits to sustain robust ecological conditions.

Spatial and temporal variations of dug well water quality in Korba basin, Chhattisgarh, India: Insights into hydrogeological characteristics

Comprehensive assessment of groundwater quality in mining-affected regions is crucial to sustainably manage water resources and protect public health and ecosystems. This study investigated the hydrogeochemical characteristics and water quality of 18 dug wells in the Korba basin, Chhattisgarh, India, an area heavily impacted by coal mining activities. Water samples were collected over three seasons (pre-monsoon, monsoon, and post-monsoon) and analyzed to determine physicochemical parameters, major ions, trace elements, and carbon content. Results revealed very high total dissolved solids concentrations ranging from 315 to 19,738 mg L−1. Nitrate levels surpassed the Bureau of Indian Standard (BIS) limit of 45 mg L−1 in over 50% of samples, reaching a maximum of 200 mg L−1. Fluoride concentrations in all samples exceeded the BIS limit (1.5 mg L−1), ranging from 1.5 to 15.2 mg L−1. The predominant water type was Ca-Mg-HCO₃, primarily influenced by rock-water interactions. Factor analysis indicated that both geogenic and anthropogenic processes influence pollution levels. Pollutant concentrations exhibited seasonal variations, generally peaking during the monsoon period. Temporal analysis from over six years revealed increasing trends for most parameters, indicating deteriorating water quality. Based on Water Quality Index values, all samples were classified as unsuitable for drinking, while assessments of irrigation water quality using various indices indicated that 61.11% of samples were suitable for agricultural use. The findings provide data to inform decision-making and public health protection in this heavily industrialized region and emphasize the urgent need for sustainable water resource management and pollution prevention strategies in the Korba basin to align with UN Sustainable Development Goals 3 (good health and well-being) and 6 (clean water and sanitation).

A Methodologic Approach to Study Large and Complex Landslides: An Application in Central Apennines

The evaluation of landslide hazards in seismic areas is based on a deterministic analysis, which is unable to account for various uncertainties in the analysis process. This paper focuses on the probabilistic local seismic hazard analysis and extends the results to the landslide hazard analysis to consider both the uncertainties of the ground deformations and the strengths. The work studies the areas between Nibbiano and Sant’Erasmo hamlets in the Camerino municipality located in central Italy, where all constructions present evidence of damage caused by both the seismic sequence of 2016–2017 and the slope instability. An exhaustive geological and geophysical investigation has clarified the geological, geomorphological, and hydrogeological characteristics of the area, enabling a new characterization of material stress-strain behaviour. The study reveals that the low stiffness of the debris covers, and their fair degree of permeability contribute to potential instability scenarios triggered by both intense rainfall and the effects of strong earthquakes. The goal was to utilize the results to support local urban planning because in-depth knowledge of the possible evolutionary scenarios of the slopes is fundamental to the management of the degree of danger for structures, especially for people. Moreover, it was shown once again how a multi-source approach, with different investigation techniques, cannot be ignored for the study of the evolution of complex landslides.

Monitoring the Impact of Artificial Structure on Hydrogeological Environment: A Case Study of Hydraulic Tunnel at Pirot Hydropower Plant.

Artificial objects, particularly tunnels used for water transport under pressure, impact the geological and hydrogeological environment to a greater or lesser extent, and it is vital to assess their contributions to groundwater quality. Although tunnels are typically lined with concrete, their interaction with the hydrogeological environment intensifies over time. In this study, the detailed spatiotemporal monitoring of all hydrogeological features within the potential influence zone of the hydraulic tunnel of the Pirot Hydropower Plant has been conducted in order to determine the degree of interaction between the artificial object and the natural environment in real time, and to assess the correlation between monitored parameters. Natural conditions of the environment were defined, as well as potential changes through the observing groundwater regimes. The monitoring network included observations of groundwater regimes at seven springs located in close proximity to the hydraulic tunnel, within the tunnel, at three piezometers, and along the river, while methods employed were hydrological monitoring, physicochemical monitoring, and groundwater piezometer sensing. Cross-correlation analysis has been applied for assessing the impact of precipitation dynamics on the spring discharge regime. The results indicate a direct influence of the tunnel on the hydrogeological environment, proving the consistency and high correlation between the monitored parameters.

Hydrogeological Characteristics and Geophysical Study of Base Aquifers in the Island of Grande Comore: Implications for Water Resources and Saline Intrusion

Hydrogeological Characteristics and Geophysical Study of Base Aquifers in the Island of Grande Comore: Implications for Water Resources and Saline Intrusion

Isotopic study for evaluating complex groundwater circulation patterns, hydrogeological zoning, and water-rock interaction in a Mediterranean coastal karst environment

In this study groundwater provenance, circulation, and rock interaction processes have been assessed by cross processing the spatial distribution of chemical and isotopic signatures in freshwater with the hydrogeological features of the coastal karst carbonate aquifer of Murgia, located in the southeastern end of Italy, along the Adriatic Sea. Thanks to widespread groundwater quality monitoring (major, minor, and trace-element analyses) and multi-isotopic measures of O, H, Sr, and B, some assumptions about complex groundwater circulation patterns, hydrogeological zoning, and water-rock interaction have been drawn. Three sectors have been distinguished into the Adriatic side of the Murgia aquifer all fed by two main recharge areas located on the most elevated, inner side of the aquifer. Each sector is characterized by different groundwater circulation patterns, residence time, and hydrogeochemical features. The water samples collected into the western sector evidence a certain degree of water-rock interaction, which allows us to assume long groundwater flow paths and residence time. On the contrary, the eastern sector of Murgia has been proven to be characterized by short residence times and a possible direct freshwater contribution even in the downstream course due to the massive presence of karst forms. Herein, the isotopic analysis of the water samples does not provide evidence of water-rock interaction. Finally, in the third, central sector, water infiltrated at different locations mixes flowing through relatively long paths even though not sufficient to allow groundwater to gain the rock's isotopic signature.

Evaluation of biocorrosion, biofouling, and health risks in the two study locations in danube alluvium

Within conducted research the results of microbiological investigations on specific metabolic (phenotypic) groups of bacteria that play crucial roles in the biogeochemical cycling of iron, manganese, nitrogen, sulfur, and carbon are presented. These bacteria are also involved in the development of biocorrosion and biofouling processes, with some posing risks to public health. Utilizing results from applied biological activity reaction tests (BART tests), processed using specialized software, potential risks for the development of microbiologically mediated corrosion, biofouling, and health risks were calculated for seven wells within two oxic sites in the Danube alluvium – Vinci and Veliko Gradište, Serbia. Moderate to high corrosion risk was determined for all seven wells at both sites (CR=5.4). Microbiological fouling risk was very high in three out of the seven investigated wells (PR=8.10). Among the seven sites studied, one site stood out based on the calculated high value of health risk coefficient (HR=8.10). The research results provide new insights into the microbiological role in aging wells in oxic groundwater of the Danube alluvium. It is demonstrated that the physicochemical composition and chemical species such as minerals, organic matter, and the specific composition of microbial communities in the studied groundwater have the potential to stimulate biocorrosion and the formation of deposits and biofilms within well structures. In addition to biochemical analyses, hydrogeological characteristics of the analyzed area are presented to define the geological stratigraphy, for which specific microbiological transformations would be expected based on the obtained results.

Identification of groundwater recharge potential zone using geospatial approaches and multi criteria decision models in Udham Singh Nagar district, Uttarakhand, India

Groundwater is a valuable natural resource, which is extensively used in agricultural, industrial as well as daily activities of human beings. It is an essential source of freshwater need of half of the world’s population. In this study Remote Sensing (RS) and Geographic Information Systems (GIS), along with Multi criteria decision models were used. The Analytical Hierarchy Process (AHP) was used to determine the weights of various themes and their classes in the study to identify the groundwater recharge zones in Udham Singh Nagar district. Nine thematic maps/layers were created using GIS methods and employed for the demarcation of groundwater potential zone (GWPZ). It was concluded that around 82 % of the area is very suitable (very good and good) for ground water recharge, which suggests that there is a significant amount of potential for artificial recharge systems to be implemented. This can help to augment the natural recharge process, improve water quality, and reduce the strain on existing water sources. Whereas only 18 % (very poor and poor) of the area has low potential to groundwater recharge is still important to consider, as it may require different approaches or strategies to improve its suitability. Validation shows that, wells data; (n = 38) have water level < 5 mbgl (83 %), whereas only (n = 8) have water less > 5 mbgl (17 %). This area could be prioritized for more extensive data collection or monitoring to better understand its hydrogeological characteristics. The findings will indeed be helpful for decision-makers in selecting suitable locations for groundwater recharge structures.

Assessment of the impact of greenhouse rainwater harvesting managed aquifer recharge on the groundwater system in the southern Jeju Island, South Korea: Implication from a numerical modeling approach

Managed aquifer recharge (MAR) is increasingly being adopted worldwide to mitigate groundwater depletion and ensure the sustainability of water resources. Rainwater harvesting (RWH)-MAR can augment aquifer storage and reduce flood damage in rural areas with dense greenhouse facilities. This study has assessed the feasibility of greenhouse RWH-MAR in Namwon agricultural areas in the southern part of Jeju Island, South Korea, by considering the injection rate and location of MAR using a numerical model. The model results showed that groundwater level increases were directly related to the infiltration rate, although spatial differences in head rise were observed owing to the spatial variability of hydraulic conductivity. In addition, installing the RWH-MAR in highland areas (>100 masl) enhanced the water level rise when compared to the expected values, indicating that a higher hydraulic gradient and thick unsaturated zone facilitated more effective MAR outcomes than in lowland areas. To optimize the contribution of source water to the agricultural water demand, placing the RWH-MAR near the pumping well improved the availability of injected rainwater to agricultural wells. This study highlights the importance of designing RWH-MAR schemes considering MAR objectives and the topographic and hydrogeological characteristics of the site.

Groundwater pollution by nitrate and salinization in Morocco: a comprehensive review

ABSTRACT Groundwater plays a critical role in supporting a wide range of human activities. However, it faces substantial challenges due to the growing demand for water and reduced precipitation resulting from climate change. Various studies have revealed the high vulnerability of Morocco's groundwater to contamination from multiple anthropogenic sources. This review focuses on assessing nitrate and salinization pollution in Moroccan groundwater, with a specific emphasis on the Gharb region. A comprehensive analysis of research conducted from 2010 to 2023, using reputable databases, underscores the pressing need to address groundwater pollution in Morocco, especially in the Gharb region. The results highlight the significant challenges faced by Morocco's groundwater resources. Agricultural practices and poorly designed irrigation systems are identified as primary contributors to nitrate contamination. Additionally, salinization in the region is influenced by factors such as seawater intrusion, hydrogeological characteristics, and irrigation practices. An integrated approach, combining laboratory analysis, remote sensing, geospatial tools, modeling, and geographic information systems technology, has proven to be effective in addressing the complex issues of assessing groundwater pollution due to nitrate and salinization. This survey presents a comprehensive framework for future research and decision-making processes aimed at achieving sustainable water resource management, preserving the groundwater heritage and safeguarding public health.

Groundwater resilience, security, and safety in the four largest cities in Denmark

Denmark's complete reliance on groundwater for water supply presents a unique case study in management of natural resources, urban planning, and water resilience in the face of climate change. This paper examines the groundwater management strategies in Denmark in general, focusing on Denmark's four largest cities—Copenhagen, Aarhus, Odense, and Aalborg— each facing distinct challenges due to their demographic, geographical, hydrogeological, and economic characteristics. Through analysis of these cities' approaches to groundwater management, this research contributes to the global discourse on sustainable urban water supply systems. As coastal groundwater cities (CGC), these urban areas must navigate the complexities of sustaining growing populations, mitigating climate change impacts, and coastal processes while ensuring the long-term viability of their groundwater resources. Copenhagen and Aalborg, built atop semi-confined fractured and locally karstic carbonate rocks, highlights the specific challenges associated with karstic groundwater systems, while, Aarhus, and Odense built on glaciofluvial aquifers faces different issues. The different groundwater challenges in these cities underscores the importance of integrating urban development with water resource management and environmental sustainability, offering valuable insights and lessons learned for other regions facing similar challenges. This study, thus not only sheds light on Denmark's groundwater management practices, but also emphasizes the need for innovative solutions to ensure the resilience of urban water supply systems in a changing climate and increasing pressures of emerging organic contaminants and elevated concentrations of geogenic elements induced by water abstraction and fluctuating water tables. Advanced Danish monitoring and modelling tools applied to support decision-making and innovation within the water sector are continuously developed and improved to support resilient and sustainable management of the available water resources.

Exploring the aquifers shaping Italy's sub-urban landscape

This review paper examines the hydrogeological characteristics and challenges of urban groundwater management in ten major Italian cities: Turin, Milano, Padova, Bologna, Roma, Pescara, Napoli, Bari, Catania, and Cagliari. Urbanization has placed significant pressure on groundwater systems, highlighting the need for sustainable management. The study categorizes the cities based on their hydrogeological settings and groundwater uses, identifying key issues such as salinization, industrial contamination, and land subsidence. The findings emphasize the importance of urban local aquifers (ULAs) for drinking water, industry, and ecological support, advocating for integrated urban water management and governance to enhance resilience against future water shortages and climate change impacts.