Land subsidence induced by groundwater extraction is a significant issue worldwide. Some of the highest subsidence rates occur in aquifer systems overlain by thick and heterogeneous aquitards composed of highly compressible sediments. Identifying the key parameters controlling vertical deformation can guide model setup and improve model efficiency and reliability. This study employs inverse modeling to evaluate the composite sensitivity of land subsidence to hydrogeological and geomechanical parameters in a stratified, heterogeneous, and highly compressible aquitard undergoing intensive groundwater extraction from an underlying aquifer. The research site, located in the Mexico Basin, features an aquitard approximately 100 m thick, monitored over 10 years using piezometric stations and multi-extensometers. Two conceptual models of vertical deformation distribution were analyzed: Case 1, with deformation occurring both within the aquitard and in compressible interbeds within the underlying aquifer, and Case 2, with deformation confined solely to the aquitard. Calibration was performed by coupling a one-dimensional nonlinear subsidence algorithm with stress-dependent parameters and the PEST parameter-estimation tool. Results indicate that total settlement and vertical deformation are more sensitive to hydraulic conductivity (K) than to compression index (Cc) or void ratio (e), with sensitivity increasing with depth, consistent with drawdown propagating upward from the aquifer. While Ccgoverns the potential magnitude of deformation, K controls the rate of change in hydraulic head, h, and thus the temporal evolution of deformation and land-subsidence rates. Case 1 best reproduced observed deformation and yielded field-consistent calibrated parameters.

Groundwater-dependent ecosystems (GDEs) are a fundamental part of groundwater flow systems, where natural flow paths discharge and support unique ecosystems. GDEs are at risk worldwide, particularly in Mexico, where groundwater abstraction and anthropogenic pollution are major issues. This study presents the first regional-scale GDEs potential mapping across the Cuitzeo Groundwater Flow System (GFS) located in Central Mexico. Traditional methods, including the Analytic Hierarchy Process (AHP) and Weights of Evidence (WoE) were implemented, as well as two machine learning (ML) methods: Logistic Regression (LR) and Random Forest (RF) using geospatial and remote sensing data. The GDEs potential maps were validated with GDEs locations using the receiver-operating characteristic (ROC) curve, area under the curve (AUC), and other evaluation metrics. The RF (AUC=0.82) achieved the highest prediction, outperforming the LR (AUC= 0.70), the WoE (AUC=0.61) and the AHP (AUC=0.59) models, and showed statistically significant superiority in specificity over all models. GDEs potential zones indicate that GDEs are widely distributed in the Cuitzeo GFS where groundwater abstraction and pollution threaten their existence. These results provide a strong robust spatial framework to deepen the study of GDEs in the area and support future conservation management practices.

Intensive groundwater extraction in Central Mexico, driven by the increasing demand from population growth, exerts significant pressure on the hydrogeological system. This has led to sustained declines in piezometric levels and a deterioration of the chemical quality of the water produced by wells all around the entire watershed. Adequate watershed management requires comprehensive information to understand its behavior.In this regard, the objective of this work is to compile hydrogeological data for a volcanic watershed that hosts one of the world's largest cities: the Basin of Mexico. The methodology consisted of consulting, collecting, and processing various databases from the National Water Commission (CONAGUA), the National Autonomous University of Mexico (UNAM), and various technical studies.The result is a groundwater compendium with data from 1960 to 2022, providing a technical analysis of changes in water levels and chemical composition associated with groundwater use. Additionally, it contains physiographic, edaphological, geological, and climatological information, along with lithological columns, isotopic, hydrogeological, and hydrogeochemical data. It also includes the locations of wastewater discharge sites, treatment and drinking water plants, deep wells, protected natural areas, the piezometric monitoring network, the delimitation of hydrological-administrative regions, administrative aquifer boundaries, and the delimitation of the regional flow system. Furthermore, all the data is available for visualization with a Geographic Information System (GIS).Finally, establishing a database and a subsequent diagnosis of hydrogeological information is of vital importance. It allows for the identification of areas of opportunity to improve our knowledge of the watershed and enables the proposal and definition of necessary works, such as the construction of piezometers, water level monitoring, and chemical and isotopic analyses, among others. All these elements are highly valuable for decision-making regarding management, infrastructure construction, and monitoring.

In groundwater management, the use of simulation–optimization (S-O) frameworks often faces operational bottlenecks that limit their adoption into routine practice. Within the context of probabilistic Wellhead Protection Area (WHPA) delineation, dynamically adjusting pumping schemes to limit the effect of transient flow on the actual delineation, so that the existing steady-state WHPA solution remains valid, may lead to prohibitive computational costs when geological uncertainty is addressed via Monte Carlo simulation. This already prohibitive cost becomes even greater when further sources of uncertainty are taken into account, such as adjusting groundwater management strategies while considering (unknown) transient flow conditions and uncertain future groundwater demand. The goal of this paper is to present and apply a set of methodologies to reduce the computational cost associated with integrating geological uncertainty while at the same time addressing unknown groundwater demand when designing optimal pumping schemes that minimize transient effects on the actual abstraction zone. Results from a synthetic application case show that: 1) the slight loss in solution quality from using fewer scenarios to represent geological uncertainty may be acceptable to groundwater modelers given the large savings in computation time and effort; 2) Gaussian processes provide a robust probabilistic way to quantify uncertainty in highly variable future water demand; 3) the uncertainty of water demand could be a major source of risk and in some cases may exceed the impact of geological uncertainty; and 4) by treating water demand as an uncertainty, the pumping strategy becomes more robust without significantly enlarging the capture zone.

Land subsidence is one of the most critical consequences of groundwater depletion, underscoring the need for management tools capable of evaluating how extraction decisions affect both aquifer conditions and ground deformation. Computational optimization models provide a powerful means to support such decision-making; however, most groundwater management studies addressing subsidence-prone systems impose constraints solely on aquifer drawdown, without explicitly controlling land subsidence. Here we develop an optimization framework that integrates management constraints on both aquifer drawdown and land subsidence rate, enabling simultaneous control of hydraulic conditions and deformation. Three constraint strategies were defined and applied to a simulated aquifer-aquitard system to evaluate the coupled response between aquifer drawdown and aquitard compression. The methodology involved formulating optimization models with alternative constraints, simulating multi-year scenarios, and comparing their impacts on groundwater dynamics and land subsidence behavior. Results demonstrate that the choice of management constraints strongly influences aquifer depletion, aquitard response, and total land subsidence. When only drawdown is constrained, total settlement reaches roughly 10 % of the aquitard thickness. Introducing a subsidence-rate constraint limits settlement to about 1.25 %, while applying only a subsidence-rate constraint reduces settlement to 0.04 % of the aquitard thickness. However, a trade-off would arise between controlling land subsidence and supplying groundwater as the volume of water produced through the management period is also reduced. These outcomes highlight the effectiveness of integrated management constraints and illustrate how integrated constraints can inform groundwater management decisions in subsidence-prone settings.

The Cuitzeo Groundwater Flow System, located in central Mexico within a volcanic rock region, encompasses two of the largest lakes in the country: Lake Cuitzeo and Lake P & aacute;tzcuaro. These lakes are sustained by both surface water and groundwater discharge, playing a critical role in local ecosystems and the surrounding population. Groundwater is particularly important for maintaining the lakes' existence. However, the behavior of the groundwater flow system in this region has not been previously described. This study compiles historical data from 170 groundwater sites within the system from different years and includes temperature (degrees C), pH, total dissolved solids (TDS), major ions, and geology in detail. The historical data provide a spatial analysis and initial characterization to study the hydrochemistry of the system, identify recharge and discharge zones, assess water-rock interaction processes, and trace the evolution of groundwater. The results highlight distinct chemical behaviors across the different zones of the study area, with the most notable being ion exchange consistent with the weathering of volcanic silicates and interaction with lacustrine sediments. This study is crucial as it offers valuable insights into the hydrochemistry and water levels of the groundwater flow system and highlights areas where additional data are needed to better understand its dynamics.

This study investigates the groundwater flow trajectories within the Cuitzeo Groundwater Flow System (GFS) in the center of Mexico, the home of the second and third biggest lakes of Mexico. We employ the End-Member Mixing Analysis (EMMA) statistical method, water table configurations and structural features, utilizing semiconservative species such as Sr2+, Li+, and Cl− in order to better understand the pattern of groundwater circulation that is essential for sustainable management of groundwater resources.Three distinct flow trajectory groups are identified: local, intermediate, and regional, each exhibiting unique hydrochemical characteristics. Local trajectories are linked to recharge waters, whereas intermediate trajectories indicate a progression towards more evolved waters. The regional trajectories, associated with fault zones along the shoreline of Lake Cuitzeo, reveal higher temperatures, suggesting geothermal influences. The lakes were fed by groundwater discharge of different flow paths, Lake Pátzcuaro is fed by local and Cuitzeo by local, intermediate and regional flow paths.Extensive groundwater extraction, particularly during the dry season and due to the demands of avocado plantations, negatively impacts groundwater and lake levels. This extraction for agricultural purposes significantly alters the natural flow patterns and hydrochemical characteristics of the lakes.This research highlights the need for integrated water resource management strategies that account for the interconnectedness of local, intermediate, and regional flow systems. Additionally, it brings international attention to the impact of avocado plantations on groundwater systems.

This paper investigates land cover, land use and vegetation changes at macro-regional, regional, local, and site spatial resolutions in the Megalopolis of Mexico City and how these affect groundwater recharge potential. Our research was framed within a transdisciplinary-holistic scope to unpack the complex social, geographic, and environmental processes often hidden when using single discipline, one-scale, one-stakeholder perspectives. Land cover/use data from the 1970s and 2018 were used as the primary input to analyze changes using remote sensing and geographical information systems. At the (macro)regional scale, land-use changes, especially human settlements, increased from about four to almost 40 % between 1970 and 2018, with a significant incursion into rural landscapes. At the local scale, analyses revealed a considerable decline in predominantly cold-humid vegetation types and conversion of agricultural fields into peri-urban landscapes. At pedon scale, hydrological balance analyses were calculated and then extrapolated to the region on behalf of soil maps information to assess groundwater recharge potentials, revealing the importance of soils as the core landscape component for water infiltration. Furthermore, social perception of changes was investigated among local stakeholders using semi-structured interviews with four communities. Nested multi-scale analyses revealed different disrupting processes hidden at one scale and evident at another. Outcomes are discussed considering their relevance for addressing transdisciplinary and theoretically applied frameworks.

The transport of noble metals (Au, Ag) by metal-rich melts in hydrothermal ore systems is now acknowledged as a complementary mechanism to complexing ligands in solution. However, it is unclear where/when both mechanisms coexist and whether metal-rich melts can be physically transported by hydrothermal fluids. Here we show evidence for a suspension-like transport of nano-to-micron-sized metal-rich sulfide-sulfosalt melts within epithermal fluids at <400 °C, forming irregular and bleb-like polymineral inclusions of Ag-Au-Cu-Pb(-Fe-Zn)-As-Sb-S-Se upon cooling. These polymineral inclusions, 5 nm to 40 µm in size, are cogenetic with fluid inclusions in quartz. Numerical modeling based on particle fluidization and settling theory shows hydrothermal fluids can mechanically transport metal-rich sulfide-sulfosalt nano-micromelts at fluid flow rates <10 –1 m/s. The chemical similarity between nano- and micron-scale polymineral inclusions suggests the coalescence of nanomelt precursors during transient transport from their source(s) to deposition sites, playing a key role in noble metal mineralization.

Groundwater and surface water form a complex and interconnected system influenced by geomorphology, geology, hydrology, and climate factors. Human activities, particularly intensive groundwater exploitation, add further complexity to these systems, especially in arid regions. Understanding groundwater-surface water interactions is essential for effective management and conservation. Maar lakes are unique surface bodies specifically connected to groundwater flow systems. In this study, we developed a conceptual model of the groundwater-surface water interaction of a semi-arid maar lake over space and time. Our objective was to understand the changes in the system and the relative influence of external forcing factors. The study focuses on Lake Alchichica, located in a semi-arid, endorheic basin in central Mexico, which has experienced a decline in water levels over recent decades. We employed a multiproxy methodology that includes the characterization of space-time variability in effective precipitation, regional hydrogeochemical patterns, isotopic and physicochemical patterns within the lake, dynamic changes in phreatic levels, and an overall assessment of anthropogenic pressures relative to natural variability. The hydrogeochemical patterns indicate that the groundwater flow path feeding Lake Alchichica is part of the regional groundwater flow system. This shows hydrogeochemical evolution from the Sierra Madre Oriental to the regional base level at playa lake Tepeyahualco. Isotopic composition and hydrochemical patterns near the lake provide evidence of groundwater-lake interactions, with increasing concentrations of various ions along the flow path, likely due to intense evaporation within the lake. From 2017 to 2021, phreatic levels declined by approximately 37.8 cm, indicating a decrease in the total volume of groundwater entering the lake, which affects the lake's water balance and level. This decline was not directly attributed to meteorological changes, suggesting alterations in the regional system. Although no significant changes in groundwater chemical composition were observed, other studies have reported changes in the chemical composition and temperature of the lake, indicating potential threats to the lake's habitat due to modifications in the groundwater-surface water interaction system.

Groundwater sustainability requires meeting current and future human needs while maintaining groundwater discharge and interactions with Groundwater-Dependent Ecosystems (GDE). The first step in including GDEs in water management policies is identifying their location and extent in the landscape. Approaches to mapping GDE include those based on expert knowledge and machine learning methods. Meanwhile, Mexico is one of the countries currently facing major groundwater challenges due to intensive groundwater abstraction, land use change, and climate change, putting to risk the structure and function of GDEs. Therefore, GDE mapping is needed in Mexico to facilitate their inclusion in water management.For this purpose, this study evaluated the performance of the Analytic Hierarchy Process (AHP) method and the Logistic Regression (LR) method to map GDEs using topographic, hydrogeological, structural, and vegetation variables obtained from remote sensing products and geospatial data in a study area located in Central Mexico. The two methods were compared by the AUC and ROC curve based on ground-truth data obtained from springs and groundwater-dependent wetland inventories.The results show insights into each method's predictive power in identifying areas associated with GDEs, with AHP emphasizing the prioritization of criteria based on expert knowledge and LR revealing statistical relationships within the dataset.The use of different explanatory variables and methods enables the development of distinct frameworks for GDE mapping, each with distinct strengths. Nevertheless, this study shows different approaches that can be successfully applied by decision-makers to map GDEs at local and regional scales and ease their inclusion into water management policies.

This study presents the first regional-scale 3D hydrogeological structural model of the Mexico Basin, constructed entirely with open-source tools using a reproducible and modular workflow. The methodology integrates hydrogeological cross-sections and geostatistical interpolation through the Universal Co-Kriging approach implemented in GemPy, enhanced by automation via Python scripting and GemGIS preprocessing. To address computational and structural challenges, the 9,000 km² basin was subdivided into ten overlapping submodels, ensuring continuity across domains while maintaining feasible computation times on standard hardware. The resulting model reproduces the main tectono-stratigraphic architecture of the basin, including major grabens and fault systems, and provides a coherent framework for hydrogeological analysis. Although limited by data availability and grid resolution, the workflow demonstrates that large-scale 3D structural geological modelling can be achieved with minimal resources. All datasets, scripts, and model outputs are openly available, promoting transparency, reproducibility, and adaptation to other data-limited regions.

ABSTRACT This dataset contains hydrogeological cross‐sections for 3D modelling in the Mexico Basin, developed using Python scripts and GIS tools. The cross‐sections are based on existing geological studies and integrate a variety of lithologies and structural features, including volcanic and sedimentary units. While the dataset provides comprehensive coverage, it does acknowledge limitations in geological and structural resolution due to the availability of data. The dataset includes shapefiles representing hydrogeological units in both line and polygon formats, alongside topographic sections, surface hydrogeological distribution and regional fault systems. Although modifications may be required for specific applications, it serves as a strong foundation for multidisciplinary studies in groundwater and geological modelling. Hosted on open‐source repositories, the data can be easily adapted for use in 3D modelling frameworks like GemPy and FloPy. This dataset is a valuable resource for understanding groundwater dynamics in the Mexico Basin and offers flexibility for future updates as new data become available or project needs evolve.

Water supply to Mexico City relies mainly on groundwater from a regional aquifer overlain by highly compressible lacustrine sediments. Intensive pumping has originated land subsidence, threatening water supply and damaging urban infrastructure. A research site where the thickness of the aquitard reaches 100 m, was instrumented with piezometers, benchmarks and extensometers and monitored for 10 years. Data are analyzed to understand the main drivers and quantify their contribution to the process of land subsidence in Mexico City. Total settlement amounted to 3.661 m, at an average rate of 0.314 m/year. Increase in total stress due to new infrastructure built near the site (a highway) at the start of the monitoring period amounts for 35% of the observed total settlement; this deformation takes place from 0 to 36 m within the aquitard, where pore pressure maintained a hydrostatic distribution. Our analysis shows that the main driver for land subsidence is groundwater pumping from the regional aquifer as most of the deformation due to consolidation (2.128 m) was registered below a depth of 82 m. Since the thickness of the aquitard at the research site is 100 m, numerical simulation shows that most of this deformation most probably takes place at interbedded compressible lenses within the regional aquifer. Future modeling efforts in Mexico City need to consider this process.

Three-dimensional (3D) geological models are essential for understanding complex subsurface systems and supporting groundwater simulation and resource management. However, regional-scale models are often constrained by computational costs, fragmented data, and inaccessible workflows. This study presents a low-cost, modular, and reproducible methodology for constructing regional 3D geological models using open-source tools, including Python scripts with the GemPy and GemGIS libraries. The workflow automates the conversion of GIS-based geological cross-sections into inputs for modeling, reducing manual workload. It was applied to the Mexico Basin, a tectonic-volcanic basin with complex stratigraphy and limited subsurface data. The basin was divided into ten sub-models, each incorporating hydrostratigraphic units and fault geometries. Despite using modest computing resources, the models captured key geological structures and maintained continuity across boundaries. All data and scripts are openly available via Zenodo, promoting transparency and reuse. This approach provides a transferable framework for 3D geological modeling in complex and data-scarce settings.

Concentrations double the salinity of seawater were found in a large portion of Ejido Chapala, southwest San Quint & iacute;n's aquifer, in northwestern Mexico. A zone with the impacts of seawater intrusion and high evapotranspiration rates was studied using different methodologies with the purpose of understanding the natural occurrence of hypersaline groundwater. A numerical groundwater flow and transport model was developed to test some hypotheses regarding the driving forces that gave it its hypersaline characteristic. To feed the numerical model, well-drilling analysis, electrical logs, step-drawdown tests, and geophysical assessments were performed. Two field piezometric campaigns were conducted in 2013 and 2015, accompanied by Electrical Conductivity (EC) profiles to gather the information to calibrate the model. Numerical modeling indicated that seawater serves as the primary source of inflow, currently with groundwater flowing towards the northeastern border. Mass concentration simulations illustrated the encroachment of seawater over time, in addition to solute migration attributed to the presence of brine hosted in fine sediments, leading to elevated Total Dissolved Solids (TDS) concentrations. Additionally, water samples were collected to perform hydrochemical and isotopic analyses revealing that midwestern well waters predominantly fall into the calcium magnesium sulfate and sodium chloride type categories. The isotopic plots suggested influences from evaporation. The saturation indices for gypsum and calcite indicated equilibrium conditions are consistent with historical geological processes in the region. Continuous monitoring and further studies are recommended to develop effective groundwater management strategies in response to ongoing salinization challenges caused by natural behavior.

The study area is located within the Yucatán Flow System in the south of Mexico, a coastal karstic system characterized by rapid infiltration of rainwater into the subsurface. Groundwater flow in this system can be considered laminar and/or turbulent, with limited contaminant retention in the soil.In Yucatan, groundwater is the sole source of water supply for human use and ecosystems. It is essential to manage its use through studies that enhance our understanding dynamics of flow systems. This study aims to develop a coupled flow model with the hydrogeochemistry of the groundwater flow system to identify transport and hydrogeochemical processes.For the hydrogeochemical analysis, physicochemical parameters were measured, and groundwater samples were collected in May 2023 for analysis of major ions and trace elements. A conceptual model was developed based on sample classification concerning chemical quality, hydrogeochemical diagrams, and a flow network created using field measurements of static water level depth and bibliographic information. The coupled flow and hydrogeochemistry model will be developed using PHAST software (PHREEQC and HST3D), which simulates groundwater flow, solute transport, and geochemical reactions.Preliminary results identified three components of the flow system:The local component is the shallowest and is influenced by the current climate.The intermediate component is located along of a fault zone; its more evolved nature suggests that the fault acts as a preferential conduit for groundwater flow.The regional component is primarily located along the coastline.Groundwater flow generally moves from south to north, but two geomorphological features alter this flow direction: the Ticul Fault and the Cenote Ring, both of which serve as preferential conduits for groundwater.The Yucatán Flow System is a complex system due to its karstic nature and its discharge into the sea. Therefore, addressing its geomorphological, hydrogeochemical, and flow complexities is crucial to achieving reliable results that can inform effective groundwater management in Yucatán.

Groundwater and surface water form a complex and interconnected system influenced by geomorphology, geology, hydrology, and climate factors. Human activities, particularly intensive groundwater exploitation, add further complexity to these systems, especially in arid regions. Understanding groundwater-surface water interactions is essential for effective management and conservation. Maar lakes are unique surface bodies specifically connected to groundwater flow systems. In this study, we developed a conceptual model of the groundwater-surface water interaction of a semi-arid maar lake over space and time. Our objective was to understand the changes in the system and the relative influence of external forcing factors. The study focuses on Lake Alchichica, located in a semi-arid, endorheic basin in central Mexico, which has experienced a decline in water levels over recent decades. We employed a multiproxy methodology that includes the characterization of space-time variability in effective precipitation, regional hydrogeochemical patterns, isotopic and physicochemical patterns within the lake, dynamic changes in phreatic levels, and an overall assessment of anthropogenic pressures relative to natural variability. The hydrogeochemical patterns indicate that the groundwater flow path feeding Lake Alchichica is part of the regional groundwater flow system. This shows hydrogeochemical evolution from the Sierra Madre Oriental to the regional base level at playa lake Tepeyahualco. Isotopic composition and hydrochemical patterns near the lake provide evidence of groundwater-lake interactions, with increasing concentrations of various ions along the flow path, likely due to intense evaporation within the lake. From 2017 to 2021, phreatic levels declined by approximately 37.8 cm, indicating a decrease in the total volume of groundwater entering the lake, which affects the lake's water balance and level. This decline was not directly attributed to meteorological changes, suggesting alterations in the regional system. Although no significant changes in groundwater chemical composition were observed, other studies have reported changes in the chemical composition and temperature of the lake, indicating potential threats to the lake's habitat due to modifications in the groundwater-surface water interaction system.

The Cuitzeo groundwater flow system in central Mexico is facing challenges due to intensive groundwater extraction, nitrate pollution, and a decline in groundwater levels. To understand the processes underlying these environmental impacts, we used compiled data from 2013 and employed cluster analysis to identify distinct groups. Four groups were identified based on flow trajectories, incorporating geological information, structural features, and hydrochemical diagrams such as Piper, Gibbs, and Mifflin. The determined flow trajectories or components consist of local, intermediate, and two regional components. The spatial distribution of these flow components is associated with recharge areas and structural features, displaying a non-sequential evolution to groundwater flow direction. This work presents preliminary findings from the analysis of environmental problems such as nitrates and a decrease in groundwater levels, contributing to an enhanced understanding of the origins of these impacts and offering insights for future solutions.

This study presents a methodology for calibrating a nonlinear groundwater flow and consolidation model in highly compressible, heterogeneous aquitards, focusing on vertical heterogeneity. Inspired by conditions in the Mexico basin, where the nature of the aquitard sediments, along with pore pressure monitoring through piezometers, plays a significant role. The model combines a nonlinear one-dimensional groundwater flow algorithm with an Ensemble Kalman Filter (EnKF) for data assimilation, correcting hydraulic head (h) and vertical hydraulic conductivity (K) distributions. Four reference cases were tested, and three data assimilation strategies were explored: (a) only h measurements, (b) only K measurements, and (c) both. Results show that all strategies provide satisfactory parameter estimations and settlement predictions, with the combined approach yielding the highest accuracy. While the method successfully simulates subsidence, its effectiveness diminishes if data assimilation only occurs in the initial simulation phase. This methodology has strong potential for predicting subsidence in real-world heterogeneous aquitards.