Sustainable Groundwater Management Research Articles

A system dynamics approach for sustainable groundwater management considering climate change, inter-organizational relationships, and domestic water saving

This article uses system dynamic modeling to examine the relationship between water allocation from the Ilam dam and groundwater fluctuation, as well as the effects of climate change, changes in inter-organizational relationships, and water demand management on water allocation and groundwater level fluctuations. The results showed that agricultural water allocation has a direct effect on groundwater level fluctuations. In the first scenario, which examined the effects of climate change, the comparison of three climate change scenarios (SSP126, SSP245, and SSP585) was carried out. The results illustrated that with temperature increasing and precipitation decreasing occurred in SSP585, the groundwater drawdown increases about 0.8 m more than SSP126. The second scenario examined the effects of changes in inter-organizational relationships. Based on the results of centrality measures in the social network analysis method, it was found that the organizational power of the stakeholder organization in the agriculture sector is greater than the ones in the environment sector. This causes the allocation to the agriculture sector to be prioritized over the environment. This scenario was analyzed by assuming a change in organizational power and giving priority to the water allocation of the environmental sector. The results showed that environmental needs (maximum 0.3 MCM) were almost entirely met in the second scenario, compared to the basic scenario. Also, the decrease in agricultural water allocation has led to an increase in groundwater usage by farmers, resulting in a 20 cm drop in groundwater levels. Therefore, regarding the sustainable management of water resources, directing attention towards alternative livelihoods for farmers can contribute to environmental water rights and the remediation of aquifers. The third scenario examined the effects of water demand management. The results showed that saving 20–25% of water in the domestic sector can reduce 40–50 cm maximum groundwater drawdown which align with sustainable groundwater management.

A new insight for geophysical and geospatial mapping quaternary alluvium of Indo-Gangetic plains for exploration and assessment of groundwater in Haryana, India

A comprehensive study on groundwater exploration and assessment was conducted, integrating geophysical, geological, lithological, and resistivity logging techniques for a holistic evaluation of groundwater resources in Haryana, India. The primary research objective was to gain insight into the geological composition of alluvial sand and its implications for groundwater occurrence in Haryana's semi-arid region. The study showcases high-resolution electrical resistivity tomography results alongside conceptual cross-sectional models and 3D lithological models, revealing buried channels that serve as groundwater sources and saturated sand as well as recharge conduits within the alluvial region of Haryana. Moreover, borehole drilling at two sites and resistivity logging data demonstrate a strong correlation between various lithologies and resistivity logs. Overall, groundwater prospect zones are delineated at depths ranging from 18 m to over 100 m based on resistivity values of aquifer zones inferred from electrical resistivity tomography models, as well as mapped thick sand layers with significant hydrogeological importance in the study area. This emphasizes the stress on the aquifer system, where groundwater is being extracted from deeper depths. The conceptual litho-sectional model reveals a thick sand signature at intermediate depths, indicating the presence of buried paleochannels extending from Galedwa (Kurukshetra) to Jubbal (Yamunanagar). Additionally, the 3D lithological models, along with the electrical resistivity tomography results, facilitate strategic planning for shallow and deep boreholes for groundwater exploration and prospecting, aiming at sustainable groundwater development and management of resources in both the present and future.

Investigating hydrological dynamics and mean residence times of springs in the Tawi catchment, India: Insights into recharge mechanisms and water source variability

This study investigates the hydrological dynamics and Mean Residence Times (MRTs) of springs in the Tawi catchment, India, aiming to elucidate recharge mechanisms and water source variability. The catchment's characteristics, including altitude, geology, and land use, are examined in relation to isotopic composition and residence times of springs at six distinct locations. The study examines seasonal variations in isotopic signatures of precipitation, revealing distinct patterns during Western Disturbances (WDs) and Indian Summer Monsoon (ISM). In addition, a composite δ18O – δ2H regression line (LMWL) is developed, that suggests significant secondary evaporation from falling raindrops as a major process shaping precipitation isotopes in the catchment. The isotopic data from six stations within the catchment demonstrate specific variations influenced by local factors. Enriched rain samples in urban areas like Udhampur and Jammu show higher secondary evaporation, while depleted samples in Chenani and Mantalai suggest a canopy cover influence. Temporal and spatial variations in spring water isotopes suggest either a consistent recharge source or isotopic damping. Mean Residence Times (MRTs) of springs indicate variations in aquifer characteristics, with longer MRTs in Chenani and Mantalai indicating deeper and more complex systems. Moderate MRTs in Pangara Jagir, and Udhampur springs, suggest a balance between storage and recharge. Hydrograph separation analysis demonstrates the dominance of WDs as the precipitation source, except for Chak Rakwal, which exhibits karstified behavior with significant contribution during the ISM. The study underscores the importance of understanding recharge elevations and delineating recharge zones for sustainable groundwater management and preservation of water quality in the Tawi catchment. By elucidating these critical aspects, the study contributes to informed decision-making and effective water resource management in complex catchment areas.

Geospatial distribution of qanats in middle eastern countries: Potential for sustainable groundwater system

Serious concerns have arisen regarding the depletion of groundwater aquifers and water shortage, particularly in the Middle East. The utilization of qanat, subterranean tunnel-wells, may serve as a solution to addressing water scarcity and present targeted strategies toward sustainable groundwater management. This research presents an analysis of the spatial distribution of active qanats in Afghanistan, Iran, Iraq, and Syria, considering the annual rainfall rate, the elevation from sea level, water stress risks, and groundwater table decline. It aims to identify the qanat sites that may be maintained and utilized. The findings reveal distinct geographical clusters of qanats, with a concentration in mountainous regions characterized by consistently high elevations ranging from 1500 to 2500 m above sea level and annual rainfall rates between 200 and 300 mm. In contrast, a more sporadic presence is observed in low-lying plains with elevations ranging from sea level to 1000 m, where the annual rainfall ranges between 300 and 600 mm. Participation in the restoration, maintenance, and utilization of qanats in regions facing high water stress and the risk of groundwater table decline, such as the central plateau of Iran, may offer a sustainable solution to water risk challenges.

Groundwater Sustainability and Land Subsidence in California’s Central Valley

The Central Valley of California is one of the most prolific agricultural regions in the world. Agriculture is reliant on the conjunctive use of surface-water and groundwater. The lack of available surface-water and land-use changes have led to pumping-induced groundwater-level and storage declines, land subsidence, changes to streamflow and the environment, and the degradation of water quality. As a result, in part, the Sustainable Groundwater Management Act (SGMA) was developed. An examination of the components of SGMA and contextualizing regional model applications within the SGMA framework was undertaken to better understand and quantify many of the components of SGMA. Specifically, the U.S. Geological Survey (USGS) updated the Central Valley Hydrologic Model (CVHM) to assess hydrologic system responses to climatic variation, surface-water availability, land-use changes, and groundwater pumping. MODFLOW-OWHM has been enhanced to simulate the timing of land subsidence and attribute its inelastic and elastic portions. In addition to extending CVHM through 2019, the new version, CVHM2, includes several enhancements as follows: managed aquifer recharge (MAR), pumping with multi-aquifer wells, inflows from ungauged watersheds, and more detailed water-balance subregions, streamflow network, diversions, tile drains, land use, aquifer properties, and groundwater level and land subsidence observations. Combined with historical approximations, CVHM2 estimates approximately 158 km3 of storage loss in the Central Valley from pre-development to 2019. About 15% of the total storage loss is permanent loss of storage from subsidence that has caused damage to infrastructure. Climate extremes will likely complicate the efforts of water managers to store more water in the ground. CVHM2 can provide data in the form of aggregated input datasets, simulate climatic variations and changes, land-use changes or water management scenarios, and resulting changes in groundwater levels, storage, and land subsidence to assist decision-makers in the conjunctive management of water supplies.

Evaluate the groundwater quality and human health risks for sustainable drinking and irrigation purposes in mountainous region of Chongqing, Southwest China

Groundwater is crucial for agriculture and domestic consumption. This research investigated the hydrogeochemical properties and contaminant sources of groundwater within the mountainous terrain of northern Chongqing, with the objective of evaluating its appropriateness for irrigation and potable use. The hydrochemical type of the groundwater was HCO3 − Ca, dominated by silicate and calcite dissolutions. High NO3− (29.03% exceeds 10 mg/L) were attributed to the overuse of agricultural fertilizers. A comprehensive evaluation was conducted to determine the groundwater suitability for agricultural and potable uses. The results showed that groundwater in the southwestern region, particularly within the Yangtze River mainstem watershed, exhibited less suitability for irrigation owing to its lower mineralization, in contrast to the northeastern region near the Daning River watershed. But this trend is reversed for drinking purposes. Overall, the groundwater was appropriate for both drinking (93.55% were classified as excellent) and irrigation (70.98% were classified as low restriction) purposes in the study area. Deterministic and probabilistic noncarcinogenic health risk analyses centered on nitrate exposure revealed that infants (with 13.79% of samples >1) were at greater risk than children (8.58%), adult males (6.98%), and adult females (5.24%). This underscores the urgency to reduce nitrogen fertilizer usage and improve water management in the region. This research will provide guidance for the sustainable groundwater management in mountainous regions.

Polycentric Groundwater Governance: Insights from the Kavango-Zambezi Transfrontier Conservation Area

This paper analyses groundwater governance within a transfrontier conservation landscape. Given the current heightened interest in groundwater development, it is imperative that more thought be given to how groundwater resources can best be managed in different contexts for multiple uses and users. Transfrontier conservation areas are areas of vast biological diversity whose functioning and ecosystem integrity depends on the availability of water to sustain ecosystems and subsequently derive economic benefit. Further, climate vulnerable rural communities depend on and form an important part of this landscape. The work highlighted in this paper is based on a study conducted in parts of the Kavango-Zambezi Transfrontier Conservation Area (TFCA), the largest TFCA in the world. Climate induced challenges such as droughts and general poor land use planning have resulted in threats to long term sustainability of freshwater ecosystems and increased incidences of human-wildlife conflicts over limited water resources. Effective groundwater governance can potentially provide pathways for alleviating these challenges. Building on the theoretical fundamentals of polycentric governance, this paper analyses the case of the KAZA TFCA in which multiple levels of governance exist. The paper discusses how to achieve coordination and accountability within a shared landscape to foster sustainable use and management of groundwater. Groundwater within a TFCA context has the potential to alleviate human-wildlife conflict over freshwater, support groundwater dependant ecosystems and sustain smallholder agriculture for the rural communities. Understanding this role of groundwater adds to the framing of freshwater governance and conservation efforts within a TFCA and the identification and development of platforms for the integrated management of groundwater. Bringing together freshwater and conservation institutions in a multi-country context towards integrated water resource management is an initial and novel attempt which forms the foundation for achieving optimal governance approaches in the commons.

Unraveling aquifer dynamics: Time series evaluation for informed groundwater management

Optimizing groundwater monitoring networks is essential for the sustainable management of this critical resource, which is vulnerable to both anthropogenic and natural changes. Focusing on the Hashtgerd aquifer in Iran, this research aims to enhance the efficiency of groundwater level monitoring systems by integrating statistical methods, artificial intelligence (AI), and hydrogeological studies. The study's core objective is to pinpoint and comprehend the factors that cause certain observation wells to become isolated from the main aquifer body, leading to parts of the aquifer being cut off from the central hydrogeological system. Employing clustering techniques on data from 29 observation wells, based on parameters like groundwater level (GWL), groundwater level change (GWLC), groundwater depth (GWD), air temperature (AT), distance (D), ground level (GL), and temperature (T) through Hierarchical Cluster Analysis (HCA), the research categorizes the groundwater information into four distinct groups. Significantly, Cluster 4 encompasses wells with similar characteristics. The analysis reveals that two wells, categorized in Clusters 1 and 2, exhibit unique behaviors, likely due to their connection to local karstic aquifers, as corroborated by geological evidence. Cluster 3's separation is determined through geophysical investigations, identifying confined conditions near specific wells, notably Wells 4 and 8. AI techniques further distinguish differences in meteorological influences and water discharges among the clusters, noting minimal weather impact on Clusters 1 and 2, considerable shallow groundwater influence on Cluster 3, and a pronounced effect of groundwater discharge on Cluster 4. This nuanced identification of aquifer segments disconnected from the main system underscores the need to refine monitoring networks for accurate assessment of groundwater resources. By leveraging a detailed analysis of aquifer complexities through state-of-the-art methodologies, the study guides towards informed, sustainable groundwater management strategies.

Groundwater hydrochemical signatures, nitrate sources, and potential health risks in a typical karst catchment of North China using hydrochemistry and multiple stable isotopes.

Nitrate pollution in aquatic ecosystems has received growing concern, particularly in fragile karst basins. In this study, hydrochemical compositions, multiple stable isotopes (δ2H-H2O, δ18Ο-Η2Ο, δ15Ν-ΝΟ3-, and δ18Ο-ΝΟ3-), and Bayesian stable isotope mixing model (MixSIAR) were applied to elucidate nitrate pollution sources in groundwater of the Yangzhuang Basin. The Durov diagram identified the dominant groundwater chemical face as Ca-HCO3 type. The NO3- concentration ranged from 10.89 to 90.45mg/L (average 47.34mg/L), showing an increasing trend from the upstream forest and grassland to the downstream agricultural dominant area. It is worth noting that 47.2% of groundwater samples exceeded the NO3- threshold value of 50mg/L for drinking water recommended by the World Health Organization. The relationship between NO3-/Cl- and Cl- ratios suggested that most groundwater samples were located in nitrate mixed endmember from agricultural input, soil organic nitrogen, and manure & sewage. The Self-Organizing Map (SOM) and Pearson correlations analysis further indicated that the application of calcium fertilizer, sodium fertilizer, and livestock and poultry excrement in farmland elevated NO3- level in groundwater. The output results of the MixSIAR model showed that the primary sources of NO3- in groundwater were soil organic nitrogen (55.3%), followed by chemical fertilizers (28.5%), sewage & manure (12.7%), and atmospheric deposition (3.4%). Microbial nitrification was a dominant nitrogen conversion pathway elevating NO3- levels in groundwater, while the denitrification can be neglectable across the study area. The human health risk assessment (HHRA) model identified that about 88.9%, 77.8%, 72.2%, and 50.0% of groundwater samples posing nitrate's non-carcinogenic health hazards (HQ > 1) through oral intake for infants, children, females, and males, respectively. The findings of this study can offer useful biogeochemical information on nitrogen pollution in karst groundwater to support sustainable groundwater management in similar human-affected karst regions.

Empowered machine learning algorithm to identify sustainable groundwater potential zone map in Jashore District, Bangladesh

Groundwater is a crucial natural resource that supplies potable water to the local population in Jashore, Bangladesh. In recent years, the district has experienced groundwater scarcity during the summer season, significantly affecting both domestic and agricultural usage, thereby impacting the local populace. However, accurately assessing its availability and quality remains a challenge. Our objective was to identify groundwater prospect zones in Jashore and provide valuable insights for management and decision-making through Explainable Artificial Intelligence (XAI). This study used 15 groundwater conditioning factors for potential zone mapping. The k-Nearest Neighbors (KNN), Neural Networks (NNET), Gradient Boosting Machines (GBM), Random Forest (RF), and Support Vector Machines (SVM) models were applied to assess groundwater suitability, resulting in the identification of five distinct areas with different levels of potential. The areas with very low suitability covered 39.37, 14.95, 107.23, 291.59, and 300.24 km2, while areas with very high suitability covered 1255.61, 969.49, 1221.99, 1958.85, and 1211.03 km2, respectively. Notably, the RF and NNET models exhibited higher accuracy, with Area Under Curve (AUC) values of 90%. The KNN, GBM, and SVM models achieved AUC values of 85%, 86%, and 88% respectively. The study reveals that the northeastern region has the greatest groundwater potential, while the southern and southwestern regions have lower capacities. The researcher's also utilized Partial Dependence Plots (PDP) technique, to analyze parameter behavior in predicting groundwater suitability. This approach provided valuable insights into the impact of various factors on groundwater potential, aiding management decisions. The study findings inform to policymakers and water resource managers in Jashore, enabling sustainable groundwater management by identifying high-potential areas. This knowledge optimizes resource allocation, ensuring sufficient supply for sustainable development.

Integrated GIS-based and water quality index for evaluation of groundwater quality in the coastal slum settlements of Lagos, Nigeria

This study aimed to identify drinking water suitability through a statistical and water quality index (WQI) approach in coastal slum settlements in Lagos, Nigeria. A total of 250 borehole groundwater samples collected for drinking purposes during the wet (125) and dry (125) seasons were analysed for their physical and chemical properties from 2019 to 2020. The physical and chemical characterisation of the region was conducted based on the correlation matrix, scree plot, PCA, Q-mode HCA, and ROC curve to identify the types of weathering, the influence of rock on precipitation and evaporation, and types of reactions that affect groundwater composition. The analytical mean concentration results revealed that SO4, Cl, TH, NO3, TDS, and PO4 surpassed the USEPA and WHO permissible limits in both seasons. The WQI results demonstrate that 7.6% and 6.7% of water samples fall into the excellent category, while 12.4% and 11.5% are moderately tolerable. In contrast, for both seasons, >100% of the samples fell into the unsuitable drinking category across SA1-SA5, SB1-SB5, SC1-SC5, SD1−SD5, and SE1−SE5. Groundwater quality mainly deteriorates due to anthropogenic activities and climatic variability. The spatial variation map indicates that groundwater quality is primarily affected during the wet season and, to a lesser extent, in a few slums during the dry season. Seawater influx in coastline areas has been identified as the main factor threatening the quality and availability of groundwater resources. As a result, the groundwater quality is mostly poor to unsuitable, and this study confirms its unsuitability for drinking. Hence, this study serves as a guide for effective action in sustainable groundwater management.

Ensuring water security by reviving selected springs in Kangra region, Himachal Himalaya, India

ABSTRACT In the Himalaya, availability of fresh water is a need of mankind, but due to numerous unsustainable developments, hill peoplesare witnessing scarcity of potable water. Hence, there is an imperative need for continuous monitoring of different water sources of Himalaya along with sustainable groundwater management practices in the highlands. The present study is based on extensive field visits investigating natural and other anthropogenic influences on mountain springs, locally known as “boweris”. In the undertaken study, eleven boweris were identified in the Salol region of Kangra, out of which two were exclusively selected as representative boweris, for their detailed studies and revival during the year 2021–2022. The physio-chemical characteristics (pH, TDS, and Electrical Conductivity) of the collected water samples from the boweris and hand pumps were found to be within the acceptable limits as prescribed by Bureau of Indian standards. The correlation between the pairs of TDS-EC depicted a strong positive relationship in both post-monsoon and pre-monsoon seasons and was found to be 0.94 and 0.99, respectively. Results of the t-test show a statistically significant difference in the mean concentrations of TDS (p = 0.02) and EC (p = 0.01) compared to pH (p = 0.39) with no significant difference at 5% significance level during both the seasons in the studied area. It was evident from the field investigations that the recharge structures constructed are facilitating the local boweris in maintaining the water level during the dry seasons. In the Bhatlahru region, the water level in the boweris rose from 127 to 159 cm, whereas in the Salol region, a rise from 119 to 142 cm was observed. The obtained results support the effectiveness and suitability of the proposed structures for the sustainable water resource management in the lower Himalaya. However, regular and long-term hydrological monitoring of the existing groundwater sources of the Himalaya is required for a better understanding of groundwater dynamics.

CALDERA: a scientific drilling concept to unravel Connections Among Life, geo-Dynamics and Eruptions in a Rifting Arc caldera, Okataina Volcanic Centre, Aotearoa New Zealand

Abstract. Silicic caldera volcanoes present major volcanic and seismic hazards but also host dynamic hydrothermal and groundwater systems and a rich but largely unexplored subsurface biosphere. Many of these volcanoes are hosted in rift settings. The intricate connections and feedbacks among magmatism, rifting, hydrothermal processes, and the biosphere in these complex systems remain poorly understood, necessitating subsurface joint observations that are only enabled by scientific drilling. The CALDERA (Connections Among Life, geo-Dynamics and Eruptions in a Rifting Arc caldera) project workshop funded by the International Continental Scientific Drilling Program (ICDP) gathered multi-disciplinary international experts in January 2023 to advance planning of a scientific drilling project within one of these dynamic, rift-hosted calderas, the Okataina Volcanic Centre (OVC), Aotearoa New Zealand. The OVC's high eruption rate, frequent unrest events and earthquake swarms, location in a densely faulted rapidly extending rift, abundant groundwater–geothermal fluid circulations, and diverse surface hot spring microbiota make it an ideal location for exploring a connected geo-hydro-biosphere via scientific drilling and developing a test bed for novel volcano monitoring approaches. Drilling configurations with at least two boreholes (∼ 200 and ∼ 1000–1500 m deep) were favoured to achieve the multi-disciplinary objectives of the CALDERA project. Decadal monitoring including biosphere activity and composition has the potential to evaluate the response of the hydro-bio system to volcano-tectonic activity. In addition to the OVC caldera-scale datasets already available, site surveys will be conducted to select the best drilling locations. The CALDERA project at the OVC would provide, for the first time, an understanding of volcanic–tectonic–hydrological–biological connections in a caldera–rift system and a baseline for global comparisons with other volcanoes, rifts, and hydrothermal systems. CALDERA would serve as an unprecedented model system to understand how and how quickly the subsurface biosphere responds to geologic activities. Discoveries will improve assessment of volcanic and seismic hazards, guide the sustainable management and/or conservation of groundwater and geothermal resources and microbial ecosystems, and provide a forum for interweaving mātauranga Māori and Western knowledge systems.

Estimation of Groundwater Residence Time Using Radiocarbon and Stable Isotope Ratio in Dissolved Inorganic Carbon and Soil CO2

AbstractEstimation of residence time of groundwater, particularly in regions with inadequate surface waters are very important for formulating sustainable groundwater management policies. We developed a technique for extracting dissolved inorganic carbon (DIC) quantitatively from water for measuring its 14C contents and presented the analytical details here. We also measured stable carbon isotope ratio (δ13C) in soil CO2 and groundwater DIC to correct the groundwater 14C ages. In addition, 14C in soil CO2 were measured for making necessary correction in the initial activity of the recharging water. The corrected 14C contents in the groundwater samples were used to estimate their residence times employing Lumped Parameter Models (LPM), a set of mathematical models to account for the processes that take place during transport from the recharge to the sampling spots. We present a case study focused on the calculation of radiocarbon ages and residence times for a groundwater sample collected from the campus of Physical Research Laboratory in Ahmedabad, Gujarat, India. The study also includes estimations of groundwater residence times using previously measured 14C ages of groundwater samples from Gujarat, India. Various factors controlling the groundwater ages in the LPM and their applicability are discussed.

Not Whether to Coordinate, But How: Concerns and Mechanism Choice Under a Mandate for Inter-Agency Coordination

Abstract A critical question in relation to inter-agency coordination is not only whether, but how, to coordinate. This question is particularly salient when agencies are subject to a top-down mandate. While inter-agency coordination can provide multiple benefits, agencies frequently have concerns about the potential risks of coordination. Differing coordination mechanisms may reduce or exacerbate those concerns. Depending on their coordination concerns, agencies will be inclined to favor certain mechanisms over others. Examination of the implementation of California’s Sustainable Groundwater Management Act, which mandates local agency coordination, indicates that coordination mechanism selection is influenced by which combination of concerns agencies hold, with autonomy considerations taking priority over other concerns. These findings suggest opportunities to improve the explanatory power of theories of inter-agency coordination by incorporating potential hierarchies of concerns, their distribution across the multiple agencies tasked with coordinating, and configurational effects. To this end, we propose a contingency theory of agency concerns and coordination mechanism choice under a mandate to coordinate.

Water Governance in Tanzania – A Synthesis of Legal and Institutional Frameworks for Groundwater Management in the Upper Great Ruaha River Catchment

The importance of groundwater resources in buffering the effects of climate change on water scarcity and security is highly acknowledged worldwide. However, groundwater development and use can only be sustainable with a more robust policy and institutional arrangements related to water governance. The purpose of this study was to analyse the legal framework of water resource development and management in order to contribute in identifying policy constraints to sustainable groundwater resource development and management in Tanzania. The paper used information from literature reviews and data collected through qualitative methods using a case study of Usangu Plains in the Upper Great Ruaha River Catchment in Tanzania. The findings reveal that water governance institutional frameworks are well structured to provide guidelines on how water as a basic human resource can be utilised and properly managed, but most importantly, these institutional arrangements place disproportionate emphasis on groundwater. Attaining sustainable groundwater development and use requires new disclosures and narratives in water policy and law, integrating both surface and groundwater resources. The weaknesses identified in groundwater governance need to be taken on Board once, the existing water institutional frameworks open to perfection for sustainable utilisation of groundwater resources

Contaminant Trends in Urban Groundwater: Case Study from Ljubljana (Central Slovenia)

Urban areas can significantly alter the quality status of aquifers if appropriate strategies to prevent and detect groundwater contamination are not implemented in time. The prevention of groundwater contamination should be a priority due to its potential long-term impact on the environment and the high cost of remediation. For effective and sustainable groundwater management, it is crucial to proactively monitor a wide range of compounds to prevent their spread, progression and increasing concentrations. This study is one of the few to analyse the trends of various urban groundwater contaminants (nitrate, sulphate, hexavalent chromium, pesticides, PCE and TCE) from a groundwater management perspective. Characteristic trends are assessed using linear regression and the Mann–Kendall method, while significant changes in trends are determined using the Darken and Pettitt tests. The time span of the analysed trends covers the transition period before and after the implementation of the Water Framework Directive (2000/60/EC) and the Groundwater Directive (2000/60/EC). This study confirms the effectiveness of enforcement measures to protect groundwater quality, as evidenced by several statistically significant decreasing trends. On the other hand, this study emphasises the importance of intervention-targeted sampling campaigns and the reporting of raw analytical values according to the ISO 11843 series of standards. This approach is essential to detect upward trends in emerging contaminants at an early stage and prevent them from reaching levels that could negatively impact the economy or even jeopardise the safety of drinking water supplies.

California's Sustainable Groundwater Management Act and the Half-Exemption of Owens Valley Groundwater Basin

California's Sustainable Groundwater Management Act and the Half-Exemption of Owens Valley Groundwater Basin

GROUNDWATER AND ECOSYSTEMS: UNDERSTANDING THE CRITICAL INTERPLAY FOR SUSTAINABILITY AND CONSERVATION

Groundwater, a vital component of the Earth's hydrological cycle, plays a central role in supporting ecosystems worldwide. This research paper explores the multifaceted relationship between groundwater and ecosystems, emphasizing its critical importance for the health and resilience of both aquatic and terrestrial habitats. The paper delves into the ecosystem services provided by groundwater, including habitat provision, water purification, and nutrient cycling. The intricate connection between groundwater availability and biodiversity is examined, highlighting the significance of groundwater in sustaining diverse habitats such as wetlands, springs, and riparian zones. Additionally, the research investigates the role of groundwater in hydrological processes, particularly its contribution to base flow in rivers and the sustenance of stream ecosystems during dry periods. Anthropogenic factors leading to groundwater depletion, such as over-extraction for agriculture and urbanization, are analyzed, emphasizing the far-reaching consequences for ecosystems. The paper proposes strategies for sustainable groundwater management, including monitoring, water-efficient agricultural practices, and nature-based solutions. It underscores the importance of policy development, community engagement, and international collaboration in preserving groundwater-dependent ecosystems. Looking towards the future, the research identifies challenges and opportunities, including uncertainties related to climate change, population growth, and global water trade. It suggests areas for further research, such as integrated hydrological models and studies on social-ecological systems, and emphasizes the need for innovative policies that prioritize ecosystem health. In conclusion, the research emphasizes the critical need for sustainable groundwater management practices, recognizing groundwater as a finite resource essential for maintaining biodiversity, ecosystem functionality, and human well-being. KEYWORDS: Biodiversity, Ecosystems, Groundwater, Sustainability, Water Management.

River–Spring Connectivity and Hydrogeochemical Processes in a Karst Water System of Northern China: A Case Study of Jinan Spring Catchment

Frequent surface water–groundwater interactions and prevalent anthropogenic inputs make karst water systems vulnerable to human disturbance. As a typical karst region in North China, the Jinan Spring Catchment has become increasingly threatened due to rapid population growth and urban expansion. In this study, the local river–spring interaction and its interference with the hydrogeochemical evolution of groundwater are evaluated based on water stable isotopes and hydrochemistry. Twenty-two karst groundwater, eleven Quaternary pore water, sixteen spring water, and thirty-two surface water samples were collected during low- and high-flow conditions over the course of a year. The isotopic signatures of four different water types display significant differences, reflecting the recharge–discharge relationship of the karst water system. Mountainous springs feature lighter isotopes, whereas urban springs have significantly heavier isotopes. The result of end-member mixing analysis shows that the surface–groundwater interaction varies spatially and temporally within the spring catchment. Urban springs receive considerable replenishment from the surface water, especially after rainy episodes (up to 50%), while mountainous springs show little hydraulic dependence on surface water leakage (4~6%). Local mineral dissolution (including calcite, dolomite, gypsum, and halite), CO2 dissolution/exsolution, and cation exchange are the main hydrogeochemical processes constraining water chemistry in the spring catchment. The deterioration of water quality can be attributed to anthropogenic influences involving the discharge of domestic effluents, agricultural activities, and irrigation return flow. The findings of this work can improve our understanding of the complex karst water system and serve as a reference for sustainable groundwater management in other karst areas of northern China.