Sustainable Use Of Groundwater Research Articles

Delineation of groundwater potential zone using geospatial tools and analytical hierarchy process (AHP) in the state of Uttarakhand, India

Groundwater plays a vital role in global climate change and substantial human needs. However, the groundwater potential zone (GWPZ) delineation is essential for fulfilling livelihood needs. In recent years, studies based on geographic information systems (GIS) have acquired much attention in groundwater exploration. Thus, in order to determine the groundwater potential zone in the state of Uttarakhand, we employ a multi-criteria decision analysis (MCDA) based analytical hierarchy process (AHP) model with overlay weighted linear combination approach in this study. For groundwater potential zone demarcation, nine thematic layers such as geology, geomorphology, LULC, drainage density, slope, rainfall, soil, TWI, and curvature were created using remote sensing (RS) images and conventional data for a geographic information system (GIS). Furthermore, the weight of the parameters has been determined using AHP technique and overlay analysis was determined using GIS tools. A thematic map was categorized as “very poor,” “poor,” “moderate,” “good,” “very good,” and “excellent” in order to determine the groundwater potential zone. According to the results, the area covered by the 'very poor' categories is 187.43 km2 (0.16 %) followed by 'poor' 2109.66 km2 (3.99 %), 'moderate' 29024.06 km2 (54.78 %), 'good' 15151.13 km2 (28.67 %), 'very good' 6537.19 km2 (12.37 %), and 'excellent' 814.84 km2 (1.55 %) with the accuracy of 89.9 %. The 'very poor' and 'moderate' groundwater potential zones were observed as 0.16 % and 54.78 %, respectively, and the possibility for GPZ gradually increased from the northeast to the southwest. The findings of this study have implications for future research on sustainable groundwater use, basin management of agriculture, and the link between groundwater and climate change.

Environmental Tracers Tritium 3H and SF6 Used to Improve Knowledge of Groundwater Sustainability of a Crystalline Rock Island Aquifer of Tobago, West Indies

Understanding the residence time, flow velocities, and storage volumes in fractured rock aquifers is essential for assessing the sustainable use of groundwater in island aquifer systems. Environmental tracers such as tritium (3H) and sulfur hexafluoride (SF6) that enter the aquifer systems through natural hydrological processes are effectively used to quantify the “apparent age” of young groundwater (<60 years) to calculate these aquifer characteristics. The island of Tobago is predominantly a fractured rock aquifer system that contains groundwater sub-basins that produce 100–1000% more than their calculated recharge. In this study, we analyzed ten samples from groundwater wells throughout the island for environmental tracers to establish the “apparent age” of the groundwater. We then estimated the active flux and storage volume of the aquifer. The 3H results of ten wells throughout the island range between 0.02 and 0.60 TU. The groundwater samples to the south of the island possess more pre-modern groundwater ages (older ages) than samples in the north of the island. These tritium values reveal age ranges between 18 and 60–plus years. This finding suggests that fractures create flow paths oriented towards the southern parts of the basin that enable the transport of groundwater across significant topographic boundaries and watershed divides. Additionally, the data may support that southern wells are connected to isolated old sources of groundwater. SF6 values range between 0.91 and 7.97 (part per trillion volume) with an interpreted age range between 18 and 39 years. Both tracers support the original hypothesis that longer residence time waters are located south of the island except for three SF6 samples which are believed to be affected by “excess air”.

DAMPAK EKSPLOITASI AIR TANAH SECARA BERLEBIHAN TERHADAP PEMENUHAN KEBUTUHAN AIR PENDUDUK DI DESA RAENYALE, KECAMATAN SABU BARAT KABUPATEN SABU RAIJUA

This study aims to determine (1) the impact of excessive exploitation of groundwater on the fulfillment of groundwater for residents in Raenyale Village (2) Strategies for overcoming the impact of excessive exploitation of groundwater on meeting the water needs of residents in Raenyale Village.The method used in this study is a quantitative descriptive research method to test hypotheses using statistical data tests. In this study there were 103 people who became the research sample consisting of people who used drilled wells, people who used dug wells and the head of Raenyale Village. Data collection methods used are questionnaires, interviews, observation and documentation. The results showed that (1). The impact of groundwater exploitation in Raenyale Village is that there are 17 dug wells which are experiencing drought due to excessive use of drilled wells which means that the community is forced to incur additional expenses by buying tanked water to meet the population's water needs. (2). The strategy for overcoming the impact of groundwater exploitation is that there are 13 people who make infiltration wells, plant trees around the well area and with community awareness and understanding of the importance of sustainable development and use of groundwater.

O- and H-isotope record of Cape Town rainfall from 1996 to 2022: the effect of increasing temperature, and the ‘water crisis’ of 2015 to 2018

Abstract The O- and H-isotope composition of rainfall collected monthly at the University of Cape Town (UCT) between 2009 and 2022 has been added to a previously published data set from 1996 to 2008 to make a continuous 27 year record. Monthly rainfall over the 27 year period has a range in δD and δ18O values from -57 to +21‰ and -8.1 to +3.5‰, respectively, and shows limited but discernible temperature and amount effects. The 27 year rainfall record defines a Local Meteoric Water Line (LMWL) whose equation is δD = 5.96*δ18O + 7.00 (r = 0.88), a slight change from the LMWL of 1996 to 2009 (6.41*δ18O + 8.89). Annual rainfall at UCT has varied from ~992 mm (2017) to 1996 mm (2013), with no systematic change in annual rainfall amount (r = −0.16). However, from 2015 to 2022, the average annual rainfall of 1 145 mm has been below the 27 year average of 1 313 mm. Mean monthly temperature has increased from 1996 to 2022 (r = 0.53), and the weighted mean annual δD and δ18O values have increased by ~4‰ (r = 0.53) and ~0.5‰ (r = 0.64), respectively, over the 27 years. The UCT data and the data for 1961 to 1974 from Cape Town International Airport plot around the same LMWL, with an average deuterium excess (d-excess) of 13.78 and 12.95, respectively. Natural springs in the area plot close to the LMWL with an average d-excess of 14.15, whereas local well-point and borehole water samples generally plot below the LMWL with an average d-excess of 10.65. These differences can be explained by relatively rapid recharge of springs and slower recharge of groundwater, with the latter containing an additional component, that could either be rainwater that fell during a period of hotter drier climate or, more probably, municipal mains water. Long-term monitoring of groundwater and spring water as well as rainwater would be of great help in assessing the sustainability of groundwater use, among other important questions.

Addressing the challenges of climate scenario-based impact studies in modelling groundwater recharge on small barrier islands at the German North Sea coast

Study RegionBarrier island at the German North Sea coast Study FocusDrinking water supply on small barrier islands strongly depends on extractions from their freshwater lens below the island when no pipeline to the mainland exists. The shape and extend of the lens is influenced by sea level change, abstraction and groundwater recharge, while groundwater recharge is the only inflow of freshwater into the system. To ensure sustainable use of groundwater in the future within changing climate conditions, knowledge in long-term groundwater recharge is required which can be obtained by climate scenario-based simulations. However, hydrological modelling on small barrier islands faces challenges, such as the lack of calibration and validation data. In addition, the historical long-term mean of main climate variables, such as precipitation and temperature, is represented inadequately in available regional climate models. In order to quantify previously mentioned topics, a water balance model was set up for the small barrier island Norderney. Subsequently, climate change impact on groundwater recharge was simulated.New hydrological insights for the region: The applied methodology increases plausibility and confidence in impact assessments compared to a-priori model applications. Future long-term development of groundwater recharge is highly dependent on the underlying climate model and emission scenario, but also affected by large uncertainties throughout the model chain, e.g. by the approach used for bias-correction. The scenario results can be directly used as forcing data for three-dimensional groundwater models.

Chemical Characteristics-Based Evolution of Groundwater in Tailan River Basin, Xinjiang, China

Groundwater plays an important role in ecological environment protection in arid and semi-arid areas. Therefore, understanding the characteristics of hydrochemical evolution is of great significance for the sustainable use of groundwater in the area of the Tailan River Basin. The Tailan River Basin is located in an arid, ecologically sensitive area in western China. In this study, we collected 42 groups of representative water samples from the Tailan River Basin and analyzed the chemical distribution in the groundwater using mathematical statistics, Piper and Gibbs diagrams, ion ratio analysis, and hydrogeochemical simulation methods. We also discussed the water–rock interactions in the groundwater hydrochemical evolutionary process. The results were as follows: (1) The chemical types of groundwater changed from HCO3·SO4-Ca·Na to SO4·Cl-Na·Ca, Cl·SO4-Na, and Cl-Na, and the total dissolved solids content increased from less than 1 g/L to more than 40 g/L from the gravel plain to the fine soil plain. (2) The Gibbs diagram, the ion ratio analysis, and the saturation index showed that the groundwater chemical characteristics in the study area were mainly controlled by water–rock interactions, as well as evaporation and concentration. Along the runoff of groundwater, halite and gypsum were dissolved. Nevertheless, dolomite and calcite precipitated. The relationship between the chlor-alkali index and [(Na+ + K+)-Cl−] and [(Ca2+ + Mg2+)-(HCO3− + SO42−)] indicated that cation exchange also affects the chemical composition of groundwater in the area. (3) Through reverse hydrogeochemical simulation, the main water–rock effect of the groundwater runoff process revealed by qualitative analysis was quantitatively verified.

Identification of groundwater potential zones in data-scarce mountainous region using explainable machine learning

Groundwater is a critical resource, yet its detailed assessment in mountainous regions is challenged by varying topography, complex hydrogeological characteristics and limited data. In this study, machine learning approaches were used to analyze the groundwater potential in five different watersheds in Nepal. Explainable machine learning models (EBM and GAMI-net) were used to identify zones with different groundwater potentials and controlling factors. The models were validated with k-fold cross-validation using the area under the receiver operating characteristics curve for the two groundwater potential models with unseen validation dataset of 0.87 and 0.88 respectively. We found that precipitation, elevation, soil bulk density, slope and lineaments primarily controls the groundwater potential in the study regions. The expected impact of each of the factors on groundwater potential was complex and multimodal. The results of this study can be used to improve water resource management and ensure sustainable groundwater use in the region.

Sustainable Water in Mining? The Importance of Traditional Owner Involvement in Commercial Water Use and Management in the Pilbara Region of Western Australia

AbstractThe mining industry is a significant water user, an issue that gains a particular prominence in arid zone mining regions, such as the Pilbara region in Western Australia (WA). Mining companies extract vast amounts of water from the groundwater aquifers to access orebodies and to dewater the mine pits. Much of this water is dumped in creeks, injected back into the aquifer downstream or used in mining processing. There is increased awareness from community members for sustainable water use in mining beyond life of mine, and the emergence of Environmental, Social and Governance (ESG) principles in the mining and metals sector signals a shift towards recognizing the importance of water stewardship. Much of the land subject to dewatering in the Pilbara is also subject to native title determinations. For Traditional Owners, important cultural values are associated with water. However, water is not adequately covered in native title, especially in relation to commercial use. We argue that Traditional Owner involvement in design and management of the use of excess water from a mining proponent's water licence (dewatering) can assist in sustainable use of groundwater, as well as provide opportunities in social and economic enterprises. As a provocation style piece, this paper is based on secondary literature, rather than ethnographic data. It explores the political and regulatory landscape of mine dewatering and outlines the limitations that have existed historically and currently and which inhibit Traditional Owners to participate in water management or commercial water interests. We also provide a high‐level analysis of several mining proponents' public policy commitments to water stewardship to assess the sustainable use of water which involves stakeholders such as Traditional Owners in water decision‐making. Finally, we identify possible opportunities and provide some recommendations, for water futures in this dry region where iron ore mining and gas extraction, already massive, are expanding further.

Coastal Groundwater-Dependent Ecosystems are Falling Through Policy Gaps.

Coastal groundwater-dependent ecosystems (GDEs), such as wetlands, estuaries and nearshore marine habitats,are biodiversity hotspots that provide valuable ecosystem services to society. However, coastal groundwater and associated ecosystems are under threat from groundwater exploitation and depletion, as well as climate change impacts from sea-level rise and extreme flood and drought events. Despite many well-intentioned policies focused on sustainable groundwater use and species protection, coastal GDEs are falling through gaps generated by siloed policies and as a result, are declining in extent and ecological function. This study summarized then examined policies related to the management of coastal groundwater and connected ecosystems in two key case study areas: Queensland (Australia) and California (USA). Despite both areas being regarded as having progressive groundwater policy, our analysis revealed three universal policy gaps, including (1) a lack of recognition of the underlying groundwater system, (2) fragmented policies and complex governance structures that limit coordination, and (3) inadequate guidance for coastal GDE management. Overall, our analysis revealed that coastal GDE conservation relied heavily on inclusion within protected areas or was motivated by species recovery, meaning supporting groundwater systems remained underprotected and outside the remit of conservation efforts. To close these gaps, we consider the adoption of ecosystem-based management principles to foster integrated governance between disparate agencies and consider management tools that bridge traditional conservation realms. Our findings advocate for comprehensive policy frameworks that holistically address the complexities of coastal GDEs across the land-sea continuum to foster their long-term sustainability and conservation.

Hydro-chemometrics of the Nubian Aquifer in Sudan: an integration of groundwater quality index, multivariate statistics, and human health risk assessment

This research employed the groundwater quality index (GWQI), multivariate statistical methods, and human health risk assessment model to investigate the suitability of groundwater for domestic uses in northern Khartoum state, Sudan. The groundwater samples were analyzed for eleven physiochemical parameters, including pH, EC, TDS, TH, Cl−, SO42−, NO3−, Ca2+, Mg2+, Na+, HCO3− and the primary investigation indicated the deviation of these parameters from World Health Organization (WHO) standards. The hydrochemical analysis revealed different groundwater facies with the dominance of Ca–Mg–HCO3 water type. Consequently, the groundwater samples were classified, based on GWQI, into three categories as 76.4% of the samples fall in the excellent water class, 17.6% are projected in the good water class, and 5.9% of groundwater samples are considered unsuitable for human consumption. The multivariate statistical methods were applied, including Pearson’s correlation analysis, principal component analyses (PCA), and hierarchical cluster analysis (HCA). Three principal components (PCs) explaining 86.07% of total variances are extracted. These PCs indicated that rock-water interactions and agricultural practices influence groundwater quality in the study area. Additionally, HCA is used to categorize groundwater samples based on the concentration of the physiochemical parameters. Consequently, three types of groundwater were identified as low, medium, and highly mineralized. In the final stage, the non-carcinogenic human health risk was assessed based on the concentration of NO3− using the United States Environmental Protection Agency (USEPA) models. The obtained hazard quotient for children indicated that 64.7% of groundwater samples are beyond the permissible limit (1 <), and the use of these samples may result in health consequences. Therefore, remedial measures are suggested for the sustainable use of groundwater.

Hydrochemical and isotopic characteristics of the Lodwar Alluvial Aquifer System (LAAS) in Northwestern Kenya and implications for sustainable groundwater use in dryland urban areas

Groundwater is a crucial resource for dryland regions such as this, where surface water resources are limited and unreliable. This paper presents a study of the Lodwar Alluvial Aquifer System (LAAS) in northwestern Kenya and its hydrochemical and isotopic characteristics, with the goal of understanding how to sustainably manage the groundwater system. As a result, the paper focuses on elucidating the hydrogeochemical and river-groundwater interaction (using environmental isotopes and major ion chemistry) of an aquifer that is located in the north-western dryland of Kenya. The study utilised environmental isotopes of oxygen-18 (18O), deuterium (2H), and tritium (3H) as tracers for establishing recharge sources and origin of groundwater. A sampling campaign involving 112 water samples was conducted to establish isotopic compositions of rain, spring, surface water (rivers, scoop holes, dams and lake) and groundwater at the peak of the wet season in May 2018. The tritium values in the study area ranged from 1.1 to 2.4 TU. Considering the median values of δ18O and δ2H in surface water and groundwater samples, four clusters emerge based on the degree of enrichment; Cluster 1 comprises the lake water (δ18O = +6.01, δ2H = +41.9); Cluster 2 is the Turkwel and Kawalase river water with slightly positive relative to VSMOW and with different δ2H values (+7.6‰ versus −9.8‰). The third cluster is the groundwater of the Shallow Alluvial Aquifer (SAA) and the Deep Aquifer (DA) (δ18O = −0.96‰ and −0.70‰; and δ2H = +0.4‰ and +0.6‰, respectively). The last cluster comprises the most isotope-depleted waters of water pans, scoop holes, Intermediate Aquifer (IA) and Turkana Grit Shall Aquifer (TGSA) with median values ranging from −2.87‰ to −2.48‰ for δ18O and −8.6‰ and −16.4‰ for δ2H. While the SAA is mainly recharge by the Turkwel River, a relationship is observed between the values deuterium in the Kawalase (−9.6‰ VSMOW) and IA (−8.6‰ VSMOW). Understanding recharge sources and aquifer vulnerability of similar strategic aquifers helps scientists appropriately advise policymakers and the water community who develop sustainable water use, aquifer protection and conservation strategies. In addition, the study contributes scientific evidence of isotopic compositions of groundwater in the Horn of Africa. Furthermore, the evidence of surface water-groundwater interaction presents a case of a fragile dryland ecosystem. Future work will involve the installation of piezometers in strategic aquifer zones to monitor groundwater levels in relation to river gauging data to quantify the amount of recharge and establish the impacts of rainfall variability in the upstream catchment.

Bridging the data gap: using remote sensing and open-access data for assessing sustainable groundwater use in Kumasi, Ghana

Abstract Groundwater use has significantly increased in the rapidly urbanising city of Kumasi, Ghana. But there is a lack of understanding of whether the groundwater system can sustain the growing demand in the future amidst climate change and rapid urbanisation. Using remote sensing datasets and a water balance approach, this study estimated the groundwater recharge and assessed how urbanisation has affected its groundwater sustainability. Sustainability is investigated by comparing multi-annual groundwater withdrawals to long-term average annual replenishment. Results show that while groundwater recharge has decreased by 80% from 1986 to 2020, mainly due to substantial (63%) loss of permeable land, groundwater consumption has seen a six-fold increase. Groundwater consumption in 2020 exceeded the long-term average groundwater recharge by 2.2Mm3, suggesting that the current groundwater use trends are unsustainable for future groundwater availability. Under a ‘business-as-usual’ scenario, a four-fold increase in groundwater consumption is predicted by 2050 while climate change and land-cover changes may reduce groundwater recharge by 10% and 55% respectively. Practical measures such as promoting artificial groundwater replenishment approaches, adopting low-impact development and instituting demand management measures must be implemented in the Metropolis. This should be informed by further studies to ascertain the exact condition of the groundwater.

Groundwater recharge influenced by ephemeral river flow and land use in the semiarid Limpopo Province of South Africa

Determining the sustainability of groundwater use in drylands with high climate variability is complex. Central to this determination is an understanding of groundwater recharge and associated processes and controls. Groundwater recharge in drylands can occur by diffuse and focused recharge (focused recharge being associated with intense episodic rainfall events and ephemeral river flow, predicted to increase and intensify with climate change). This study evaluated the relative significance and dominant controls on these two recharge processes. Ten groundwater hydrographs with multidecadal observations were collated from the Limpopo Province, South Africa, based on their proximity to river channels and rain gauges, representing diversity in local climate, landscape, vegetation, and hydrogeological conditions. The hydrographs showed that groundwater-level rises are sensitive to rainfall intensity during the rainy season, with generally larger increases after years with large episodic rainfall events, which disproportionately contribute to groundwater replenishment. Recharge processes and annual recharge volumes were quantified using the water-table fluctuation method and the numerical model HYDRUS-1D. This allowed for the inference of additional recharge contributions from focused recharge in proximity to ephemeral rivers, up to a factor of five relative to diffuse recharge. The analysis revealed synchronicity and linear correlation between annual river discharge and recharge close to the river, substantiating the importance of focused recharge close to the river network. The study showed that recharge in drylands is subject to large spatial and temporal variation and that consideration of focused and episodic recharge is critically important for managing groundwater resources at various scales in these regions.

Spatial Variation Characteristics, Influencing Factors, and Sources of Hydrogeochemical of Surface Water and Groundwater in Mountainous Area of Hutuo River

Surface runoff has dropped sharply in the mountainous area of the Hutuo River, posing a huge challenge to the sustainable use of groundwater in the North China Plain (NCP). The Taihang Mountain area is the main recharge source area of groundwater in the NCP. An in-depth study of spatial variation characteristics, influencing factors, and sources of hydrogeochemical characteristics of surface water and groundwater in the mountainous area of the Hutuo River can facilitate a comprehensive understanding of regional water resource status and sustainable utilization of water resources. Based on isotopic, hydrogeochemical, and mathematical statistics methods, this study analyzed spatial variation of hydrochemical characteristics in surface water and groundwater and its sources and main controlling factors. The results showed that the river water, well water, and spring water were all recharged by atmospheric precipitation in the mountainous areas of the Hutuo River. Under the combined influence of natural factors and human factors, the hydrogeochemical characteristics of river, well, and spring water showed large spatial differences. On the whole, the hydrochemical types of mainstreams were relatively concentrated. In the upper and lower mining reach areas, the mainstream water chemical type was dominated by Ca·Mg-SO4·HCO3, whereas that in the natural vegetation area (middle reach:between Qingshui River and Longhua River) was dominated by Ca·Mg-HCO3·SO4. In the upper stream, the main hydrochemical type of the Yukou River and Ehe River tributaries was Ca·Mg-SO4·HCO3, which was consistent with that of the main stream. The main hydrochemical types of the Muma River and Qingshui River tributaries were Ca-HCO3, Ca·Mg-HCO3, and Ca·Mg-HCO3·SO4 in the midstream. The main hydrochemical types of the Mianhe River and Yehe River tributaries were Ca-SO4, Ca·Mg-SO4, and Ca·Mg-SO4·HCO3. Mineral dissolution was still the main controlling factor for the hydrochemical characteristics of surface water and groundwater in the mountainous area of the Hutuo River. The contribution rates were 69.86% and 18.84% for mineral dissolution and human activities, respectively. Therefore, in the future, water resource utilization in the upper reaches of the Hutuo River should not only consider the issue of water quantity but also a series of water environment problems such as nitrate pollution and mining pollution caused by human activities.

Newspaper coverage of water security issues in the water‐stressed Northern Province of Sri Lanka: An explorative study of three Tamil dailies

AbstractNewspapers remain as an effective medium for circulating information among the public in the North of Sri Lanka and have the potential to influence public opinion and people's behavior regarding sustainable use of groundwater. This study investigated the extent and scope of newspaper coverage on the subject of water security in the Northern Province of Sri Lanka. Three newspapers, namely, Yarl Thinakkural, Uthayan, and Valampuri were chosen on the basis of readership, circulation in print form, and for being daily local or regional papers in Tamil. The content analysis of 1214 articles published in 2019 and 2020 in the three papers indicated that as much as 80% of space in the papers was allocated to reporting general news items and events in the community related to new water projects, rain and floods or drought events and announcements of allocation of irrigation water for farming. Only 20% of newspaper space was taken up by non‐news articles including advertisements related to water. We conclude by saying that the effect of these newspapers on their audiences would merely be to inform rather than to set agendas or frame the discourse in society, let alone persuade readers enough to make changes. The study revealed the significant potential that exists for newspapers to shift their culture of simply reporting of facts in a dispassionate way to one of environmental journalism with a degree of advocacy in view of the critical nature of the security of groundwater in the Northern Province.

Sustainable use of water from a tropical aquifer

AbstractThe objective of this work is to analyze and interpret the components or hydrogeological, physical, and chemical variables of the San Diego aquifer to describe it and explain its influence on the sustainable use of groundwater for the providing of this locality. The San Diego municipality covers most of the area of the aquifer and is an area of high urban development that currently needs the contribution of groundwater due to the deficit presented by the main supply from the Central Regional System. Said aquifer is a set of geological strata located within the limits of the San Diego River basin, in the state of Carabobo, which are capable of storing groundwater and transmitting it. Data on lithology, porosity, and pumping level were investigated, which allows calculating an estimate of the volume of water available in the aquifer. Regarding the quality of the water, the data on hardness, chlorides, sulfates, nitrates, conductivity, calcium, magnesium, and pH, show that the water towards the center and north of the aquifer is of good quality, being able to classify it as type 1A, while toward the southern end—this is of lower quality, where the mineral parameters are higher, which is related to the probable intrusion of brackish water from Lake Valencia. It is concluded by establishing that the volume of groundwater, its availability, extraction feasibility, and its quality, make it suitable for urban supply and that said extraction is sustainable. But a better‐integrated type of management must be designed, considering the contribution of the Regional System of the Center and the adequacy of the distribution networks.

Developing a community based participatory model for efficient and sustainable use of groundwater – An exploratory research using system dynamics in a village in south India

The paper presents a model developed collaboratively with farmers in a south Indian village to visualize productive, efficient and sustainable usage of groundwater. This model is based on information and data collected over several years and analyzed through participatory community interactions. The objective of the participatory modeling process is to trigger thinking among the community regarding the use of groundwater in a sustainable manner. It is expected that a model of sustainable groundwater use would evolve if the community is able to perceive groundwater as a community resource. With the System Dynamics approach, the community was enabled to understand the complexities in groundwater availability patterns, its over exploitation and its impact, and also to visualize scenarios that suit their context for sustaining their agriculture. These scenarios effectively project the potential of groundwater as a critical and productive source of irrigation so as to sustain the agricultural base of the village community. They also helped in visualizing the benefits of collectivizing groundwater from the existing borewells within the village boundaries. The study reveals that there is a possibility for more sustainable use of groundwater in the selected village provided the community makes a viable choice to restrict the irrigated area and pool groundwater to provide protective irrigation to rainfed crops in a much larger area.

Dwindling Ground Water Table: An Ecological Study of Southern Haryana

The dwindling ground water level is one of the critical issues that plague India in the present times. This research study primarily has its basis in the secondary data, gathered from the Ministry of Water Resources. The main aim of the present research study is to highlight the issues related to ground water in various parts of India with the main focus on southern part of Haryana state. The spatial pattern of the ground water depth is studied using the secondary data from various sources. The water table depth and fluctuation maps in Arch GIS 9.3 are analysed by making use of geological analysis extension. The water elevation is examined by employing the Kriging estimator. Also, the different ways of prevention that can help in checking the quick dwindling of ground water table are discussed so that the sustainable use of ground water can be encouraged and achieved. It is observed that the menace of ground water depletion has posed alarming threat to the states of Punjab, Haryana, Uttar Pradesh and some south Indian states. This is attributed mainly to the agricultural, industrial and human needs amidst the ever-rising rate of population in India. In the southern Haryana, the Mahendergarh district and Firozpur block of Mewat area have been identified as most critical zones in relation to water depletion. The study suggests judicious and sustainable use of water resources so as to check the alarming dwindling of the ground water table.

Modelling the impacts of climate change and management options on sustainable groundwater use in an irrigated agriculture landscape

Declining groundwater resources are a big concern for irrigated agriculture worldwide. This study investigated the causes of declining groundwater and how future climate and management measures impact the groundwater resource in Bangladesh. A conceptual hydrological model (NAM) was used to quantify catchment runoff, groundwater recharge and evapotranspiration loss and a hydraulic model (MIKE11) was used to quantify changes in river flow. The models were calibrated using observed water level, discharge, groundwater level (GWL) and actual evapotranspiration (ET). The modelling encompassed five contrasting climate scenarios of rainfall and potential evapotranspiration (PET) and a management scenario of additional surface water irrigation. The results show that GWL is declining across 16 administrative districts in the northwest region of Bangladesh. On average, the annual decline varies from 20 to 30 mm except for two southern districts where the annual decline was more than 80 mm. Declining rainfall and increasing use of groundwater for irrigation were the principal causes of declining GWL across the region. Under the climate change scenarios, modelled groundwater conditions improve due to increased rainfall. The increase in river water extraction for irrigation also produced positive outcomes for GWL (i.e., lessening the declining rate).

Groundwater potential assessment using GIS-based ensemble learning models in Guanzhong Basin, China

Groundwater plays a crucial role in sustaining industrial and agricultural production and meeting the water demands of the growing population in the semi-arid Guanzhong Basin of China. The objective of this study was to evaluate the groundwater potential of the region through the use of GIS-based ensemble learning models. Fourteen factors, including landform, slope, slope aspect, curvature, precipitation, evapotranspiration, distance to fault, distance to river, road density, topographic wetness index, soil type, lithology, land cover, and normalized difference vegetation index, were considered. Three ensemble learning models, namely random forest (RF), extreme gradient boosting (XGB), and local cascade ensemble (LCE), were trained and cross-validated using 205 sets of samples. The models were then applied to predict groundwater potential in the region. The XGB model was found to be the best, with an area under the curve (AUC) value of 0.874, followed by the RF model with an AUC of 0.859, and the LCE model with an AUC of 0.810. The XGB and LCE models were more effective than the RF model in discriminating between areas of high and low groundwater potential. This is because most of the RF model's prediction outcomes were concentrated in moderate groundwater potential areas, indicating that RF is less decisive when it comes to binary classification. In areas predicted to have very high and high groundwater potential, the proportions of samples with abundant groundwater were 33.6%, 69.31%, and 52.45% for RF, XGB, and LCE, respectively. In contrast, in areas predicted to have very low and low groundwater potential, the proportions of samples without groundwater were 57.14%, 66.67%, and 74.29% for RF, XGB, and LCE, respectively. The XGB model required the least amount of computational resources and achieved the highest accuracy, making it the most practical option for predicting groundwater potential. The results can be useful for policymakers and water resource managers in promoting the sustainable use of groundwater in the Guanzhong Basin and other similar regions.