Sustainable Management Of Groundwater Resources Research Articles

Investigating the impact of long-term agricultural practices on selected peri-urban aquifers in tropical Southwest India

Hydrogeochemical evaluation of groundwater resources is of paramount significance in the tropics as it aids identification of safe and sustainable water resources. Evaluation of heavy metals in water is necessary as they integrate into the food chain and pose deleterious effects on human and aquatic life. To identify the extent of heavy metal occurrence in groundwater, 40 samples were collected seasonally from dug wells located in agriculture-intensive areas and analysed for physicochemical parameters and heavy metals. Water quality and pollution indices were used to evaluate overall groundwater quality and threat to humankind. The heavy metal concentrations in groundwater were observed in the increasing sequence of Zn > Cu > Pb > Ni > Co (post-monsoon) and Zn > Pb > Cu > Ni > Co (pre-monsoon). Heavy metal pollution index (HPI) revealed that the dissolved heavy metal content was found below critical value. Correlation analysis (CA) and principal component analysis (PCA) revealed that the groundwater hydrochemistry is influenced by geogenic (rock-water interaction, precipitation, simple dissolution, and base-exchange reactions) and anthropogenic sources. The results of this study will help in developing a long-term groundwater monitoring system for metal pollution, sustainable management, and conservation of peri-urban groundwater resources to achieve water security.

Bridging the Data Gap between the GRACE Missions and Assessment of Groundwater Storage Variations for Telangana State, India

Because of changing climatic conditions, uneven distribution of rainfall occurs throughout India. As a result, dependence on groundwater for irrigation has increased tremendously for industrial and domestic purposes. In India approximately 89% of agricultural demands are met through groundwater. Due to increases in population, demand for groundwater and lack of effective utilization have resulted in rapid depletion of groundwater in most parts of the country. Therefore, quantifying groundwater resources is a serious concern in populated states of India, because it is now difficult to supply enough water to every citizen, and will remain so in the future. Because of difficulties in accessing observation data, researchers have begun to depend on satellite-based remote sensing information to deal with groundwater variations. The present study deals with filling the data gap between Gravity Recovery And Climate Experiment (GRACE) and GRACE Follow On (GRACE FO) missions using multilayer perceptron’s (MLPs) during 2017–2018 to obtain a continuous terrestrial water storage anomaly (TWSA) series from 2003 to 2020 for Telangana state, India. The MLP model performed well in predicting the TWSA, with a correlation coefficient of r = 0.96 between modeled TWSA and GRACE TWSA during the test period. Telangana state observed negative TWSAs (annual) in the years 2003, 2004, 2005, 2009, 2012, 2015, and 2016–19. This TWSA series (2003–2020) was then used to evaluate regional groundwater storage anomalies (GWSAs) in Telangana state, which is considered to be one of the water stress regions in India. The TWSAs were converted to GWSAs using Global Land Data Assimilation System (GLDAS) parameters. The Telangana state experienced decreasing GWSA in the years 2005, 2009, and 2012, and from 2015 to 2019, leading to severe droughts. Groundwater well measurements were obtained from the Central Groundwater Board (CGWB) and converted to GWSA at a seasonal scale. The GWSAs obtained from GRACE (GWSAGRACE) were converted to seasonal values and compared with GWSAs obtained from observation well data (GWSAobs). The performance metrics of r = 0.74, RMSE = 5.3, and NSE = 0.62 were obtained between (GWSAGRACE) and (GWSAobs), representing a good correlation among them. Over the past decade, Telangana state has significantly relied on groundwater resources for irrigation, domestic, and industrial purposes. As a result, evaluating groundwater storage variations at a regional scale may help policy makers and water resource researchers in the sustainable utilization and management of groundwater resources.

Methods of Groundwater Recharge Estimation under Climate Change: A Review

Groundwater resources have deteriorated in many regions as a result of excessive use to satisfy increasing water demands. Furthermore, climate change has an influence on groundwater in terms of quality and quantity. An investigation of climate change impacts on quality and quantity of groundwater is vital for effective planning and sustainable management of groundwater resources. Despite of the importance of climate change impact studies on groundwater resources, climate change impact studies related to surface water resources have attracted more attention from the research community, leading to limited understanding of the groundwater and climate change relationship. In this paper, a systematic review of the latest literature related to the impact of climate change on groundwater recharge was carried out to provide guidance for future studies.

Origins of groundwater nitrate in a typical alluvial-pluvial plain of North China plain: New insights from groundwater age-dating and isotopic fingerprinting

Identifying nitrate sources and their temporal evolution in different land use is important for the sustainable management of groundwater resources. In this study, groundwater dating (3H–3He and time series of 3H) was combined with chemical and stable isotope analyses to resolve the evolution of nitrate sources and the driving mechanism of nitrate contamination. Approximately 75% of the groundwater samples (collected in 2014 and 2018) had nitrate concentrations exceeding World Health Organization's guideline for drinking water (50 mg/L), and 44% exceeded the groundwater quality standard of China (88.6 mg/L), indicating severe nitrate pollution. The shift of nitrate sources in different land use was identified using stable isotope composition of nitrate and groundwater age. The decreasing median value of δ15N from 10.6‰ to 7.5‰ of dated groundwater in farmland irrigated by clean water indicated the shift of nitrate sources from manure toward the mixing of fertilizer and manure due to the increased application of chemical fertilizers from intensive plant farming since 1980s. Comparably, the trend of increasing δ15N (the median value from 7‰ to 12‰) in farmland irrigated by wastewater might be attributed to the decreasing proportion of industrial wastewater since 2000s. The prevailing sources of nitrate in residential area were manure and sewage, and showed no obvious change along the recharge time. Driven by rapid urbanization, the nitrate sources of land use change area exhibited a marked shift from inorganic fertilizers toward manure and sewage. Principal component analysis (PCA) on nitrate concentrations with multiple parameters indicated nitrogen input in agricultural development and urbanization were the main controlling factors of nitrate contamination in the study area. The study results are a good reference for groundwater management in regions with nitrate source change during the process of rapid urbanization and agricultural intensification. The coupling of chemical, isotopic analyses and groundwater dating proved to be invaluable and should be applied in similar studies of nitrate contamination.

Hydrogeochemistry and quality evaluation of groundwater and its impact on human health in North Tripura, India.

Groundwater contamination becomes an alarming threat to the provision of ecosystem services and natural resources. A very high level of groundwater contamination has been observed in the northeastern states particularly in North Tripura district. Therefore, the present study considered the region as a case study to evaluate the hydrogeochemical facies, heavy metal pollution and irrigation indices, and their impact on human health. For the investigation, we have collected a total of 35 groundwater samples from North Tripura district. Hydrogeochemical facies through Piper plot reflect Ca2+-Mg2+-HCO3- and Na+-HCO3- as dominant water types. Gibbs plot identifies the dominance of rock-water interaction process in groundwater hydrochemistry. Geochemical plots indicate the dominance of silicate weathering, ion exchange and carbonate dissolution processes in groundwater mineralisation. The order of trace metal contaminations follows Fe > As > Zn > Mn > Cu > Pb. Results of heavy metal indices suggest above 80% samples are at high risk due to high Fe contamination. The risk of the heavy metal indices is associated with rising elevation in southern part of North Tripura. Findings of health risk assessment study imply that children face much carcinogenic and non-carcinogenic risks than adults because of unsafe levels of Fe and As. Multivariate statistical tools are applied to unravel interrelationships among all ions and trace metals as well as probable hydrogeochemical processes in groundwater. Results of Wilcox and USSL plots suggest 77% samples meet irrigation suitability criteria. Besides, the analysis suggests a better insight to identify hydrogeochemical processes controlling groundwater chemistry and the suitability of groundwater for irrigation and drinking purposes. The study also suggests treatment and sustainable management of groundwater resources is compulsory to reduce trace metal contaminations before public use.

Multi-tracer approach to understand nitrate contamination and groundwater-surface water interactions in the Mediterranean coastal area of Guerbes-Senhadja, Algeria

Implementing sustainable groundwater resources management in coastal areas is challenging due to the negative impacts of anthropogenic stressors and various interactions between groundwater and surface water. This study focuses on nitrate contamination and transport via groundwater-surface water exchange in a Mediterranean coastal area (Guerbes-Senhadja region, Algeria) that is heavily affected by anthropogenic activities. A multi-tracer approach, integrating hydrogeochemical and isotopic tracers (δ2HH2O, δ18OH2O, 3H, δ15NNO3 and δ18ONO3), is combined with a Bayesian isotope mixing model (MixSIAR) to (i) elucidate the nitrate sources and their apportionments in water systems, and (ii) describe potential interactions between groundwater and surface water. Results from nitrate isotopic composition and the MixSIAR model show that nitrate concentrations mainly originate from sewage and manure sources. Nitrate derived from the sewage is attributed to urban and rural wastewater discharge, whereas nitrate derived from the manure is related to animal manure used to fertilise agricultural areas. High apportionments of nitrate-based atmospheric precipitation are identified in groundwater and surface water; a finding that is specific to this study. The multi-origin stresses combined with evidence of interactions between surface water and groundwater contribute to negatively impacting large parts of the study coastal area. The outcomes of this study are expected to contribute to sustainable management of coastal ecosystems by drawing more attention towards groundwater use and protection. Furthermore, this study may improve scientists' ability to predict the behavior of anthropogenically impacted coastal ecosystems and help decision-makers elsewhere to prepare suitable environmental strategies for other coastal ecosystems currently undergoing an early stage of groundwater resources deterioration.

Geo-statistical analysis of ground water fluctuations for sustainable management of groundwater resources within the chaliyar basin, southwest India

Ground water is the primary source for potable water and it forms the fundamental connecting link amongst the Climates, Society & Natural Ecosystem. Phenomenon like climate change has a marked influence on ground water recharge giving rise to spatial variation in ground water levels. Today, fluctuations in ground water level have become a major problem and their study is of prime importance from water security & sustainable development point of view. To meet such challenges, geospatial technologies have proven to be an effective enabler i.e. spatial interpolation mechanism using geo-statistical analysis has become very popular. The Kriging method is an example of such techniques. Hence, this paper attempts to study & analyze the spatio-temporal variations of ground water levels pertaining to 29 observation wells located in Chaliyar basin, Southwest India for which Geo-statistical analysis was performed using ordinary Kriging method in Arc GIS environment. Finally, the spatial maps showing the ground water level fluctuations were generated for the Chaliyar basin which could be used for sustainable management & planning of Ground water resources within the basin.

Strategies to sustainable management of groundwater resources in Romeshkan plain

سابقه و هدف: در کشور ایران از حدود 5/88 میلیارد مترمکعب آب استحصال‌شده از منابع سطحی و زیرزمینی، حدود ۸۳ میلیارد مترمکعب یعنی 5/93 درصد به بخش کشاورزی اختصاص می‌یابد، در ایران بخش کشاورزی بزرگ‌ترین مصرف‌کننده آب است. مصرف رو به افزایش منابع آب سطحی و زیرزمینی، معلول افزایش جمعیت، افزایش سطح زیر کشت و تولیدات کشاورزی هست که به‌تبع آن سبب کاهش دسترسی به منابع آب و افت سطح ایستابی و تخلیه آبخوان‌ها شده است. آمارها نشان می‌دهند که مصرف رو به افزایش این منابع استراتژیک، سبب تهدید کمیت و کیفیت این منابع شده است به ­طوری ­که هم ­اکنون تعداد زیادی از دشت­ های کشور در شرایط بحرانی قرار دارند. دشت رومشکان، یکی از دشت‌های واقع در حوضه کرخه هست که در طی چند دهه اخیر با کاهش قابل توجه از منابع مواجه شده است (دشت رومشکان یک دشت ممنوعه است) و این تحقیق قصد دارد به تدوین راهبردهایی در راستای مدیریت پایدار منابع آب این دشت بپردازد.مواد و روش‌ها: پژوهش حاضر از نوع تحقیقات کاربردی و توصیفی (غیر آزمایشگاهی) می‌باشد که با استفاده از تکنیک دلفی فازی به بررسی راهبردهای مدیریت پایدار دشت رومشکان پرداخته است. حجم نمونه این تحقیق 28 نفر از اساتید، کارشناسان، مسئولین و کشاورزان آگاه به موضوع در شهرستان‌های خرم آباد و رومشکان بودند که با به‌کارگیری روش نمونه‌گیری هدفمند گلوله‌برفی انتخاب شدند. در این تحقیق برای توصیف دشت رومشکان داده‌های ثانویه مورد نیاز از سازمان‌های مرتبط اخذ شد. همچنین داده‌های مرتبط به کاهش منابع آب این دشت در طی 3 دهه اخیر نیز مورد بررسی قرار گرفت.نتایج و بحث: در این تحقیق مشخص شد که با وجود بحرانی بودن شرایط کنونی و ممنوعه بودن دشت رومشکان، معیشت جوامع روستایی و بهره‌برداران عمدتاً وابسته به بخش کشاورزی بوده و همچنان کشت محصولات آب­دوست در سطح گسترده وجود دارد. از سویی دیگر ساختار عرضه و بهره‌برداری از منابع آب به‌صورت سنتی می‌باشد و اراضی کشاورزی این دشت فاقد سیستم نوین آبیاری هستند. اولویت راهبردها "توسعه اشتغال پایدار روستایی با تأکید بر متنوع‌سازی اقتصاد جوامع روستایی" بوده است تا از فشار بر منابع کاسته شود و این امر نیز قطعاً مستلزم"توسعه انسانی کنشگران مرتبط با آب و توانمندسازی جوامع روستایی" خواهد بود. از سویی دیگر، "توسعه فناوری‌های متناسب و کم آب بر در منطقه" نیز می‌تواند به اصلاح ساختار سنتی عرضه و مصرف این منابع کمک شایانی داشته باشد. همچنین"بازنگری در حکمرانی آب با تأکید بر شاخصه‌های حکمرانی خوب" توجه به بعد سیاست‌گذاری را نشان می‌دهد که تصمیم‌گیری در سطح کلان‌تر را می‌طلبد.نتیجه‌گیری: نتایج این تحقیق نشان داد که مدیریت پایدار منابع آب زیرزمینی در این دشت صرفاً با تکیه ‌بر بعد فنّاورانه محقق نخواهد شد و علاوه بر بعد مذکور، ابعاد اقتصادی، اجتماعی، سیاست‌گذاری و زیست­محیطی باید مورد توجه قرار گیرند. این بدین معناست که اکنون که شرایط دشت بحرانی می‌باشد و سفره‌های زیرزمینی قادر به تامین آب برای تولیدات بخش کشاورزی نیستند، لذا باید به موازات اصلاح ساختار مصرف آب و نیز حفاظت از این منابع، با اشتغال‌های غیر‌زراعی و متنوع‌سازی اشتغال جوامع روستایی، از فشار بر این منابع کاست.

Assessment of spatial and temporal variability of groundwater level in the aquifer system on the flanks of Mount Meru, Northern Tanzania

Study regionMount Meru located in Northern Tanzania. Study focusGroundwater level monitoring is essential for uncovering the spatial-temporal variation of groundwater levels in a studied aquifer, helping discussions on the sustainable use and management of groundwater resources. This study analyses the spatial and temporal variability of groundwater level in the shallow aquifer system on the flanks of Mount Meru. Time series analysis of groundwater level measurements obtained in two hydrologic years: 2018–2019 and 2019–2020 is applied. New hydrological insights for the regionOn the north-eastern flank of Mount Meru, at Ngarenanyuki, there is a rise of about 1.80 m between the static water levels in April 2018 and December 2020 in the shallow aquifer, whereas on the western flank, at Mamsa, there is a decrease of about 0.50 m between the static water levels in May 2018 and December 2020 in the shallow aquifer, this can be attributed to low/reduced recharge (due to very low hydraulic conductivity and semi-confined condition of the aquifer), or exploitation. Hence, the current pumping practices in the aquifer on the western flank should be restrained for sustainable groundwater management.

Effect of hydrogeochemical behavior on groundwater resources in Holocene aquifers of moribund Ganges Delta, India: Infusing data-driven algorithms

One of the fundamental sustainable development goals has been recognized as having access to clean water for drinking purposes. In the Anthropocene era, rapid urbanization put further stress on water resources, and associated groundwater contamination expanded into a significant global environmental issue. Natural arsenic and related water pollution have already caused a burden issue on groundwater vulnerability and corresponding health hazard in and around the Ganges delta. A field based hydrogeochemical analysis has been carried out in the elevated arsenic prone areas of moribund Ganges delta, West Bengal, a part of western Ganga- Brahmaputra delta (GBD). New data driven heuristic algorithms are rarely used in groundwater vulnerability studies, specifically not yet used in the elevated arsenic prone areas of Ganges delta, India. Therefore, in the current study, emphasis has been given on integration of heuristic algorithms and random forest (RF) i.e., “RF-particle swarm optimization (PSO)”, “RF-grey wolf optimizer (GWO)” and “RF-grasshopper optimization algorithm (GOA)”, to identify groundwater vulnerable zones on the basis of field based hydrogeochemical parameters. In addition, correspondence health hazard of this area was assessed through human health hazard index. The spatial distribution of groundwater vulnerability revealed that middle-eastern and north-western part of the study area covered by very high and high, whereas central, western and south-western part are covered by very low and low vulnerability zones in outcomes of all the applied models. The evaluation result indicates that RF-GOA (AUC = 0.911) model performed the best considering testing dataset, and thereafter RF-GWO, RF-PSO and RF with AUC value is 0.901, 0.892 and 0.812 respectively. Findings also revealed the groundwater in this study region is quite unfavorable for drinking and irrigation purposes. The suggested models demonstrate their usefulness in foretelling sustainable groundwater resource management in various deltaic regions of the world through taking appropriate measures by policy-makers.

Determining Irrigation Requirements of Extensive Crops Using the Typical Meteorological Year Adjusted to the Growing Cycle Period

In the Castilla-La Mancha (CLM, Spain) region, most of the irrigated area is managed by two different strategies in which the previously defined irrigation requirements of crops affect both the distribution of crops and the sustainable management of groundwater resources. Thus, in the western Mancha system, the amount of irrigation water per farm is limited, while in the eastern Mancha system the irrigable area per farm is limited. Therefore, the use of average irrigation requirements in these areas may cause yield drops in dry years and the overuse of groundwater. Consequently, the main aim was to achieve a better approach to the irrigation requirements of the main extensive crops in CLM (maize (Zea mays L.), onion (Allium cepa L.), garlic (Allium sativum L.), and barley (Hordeum vulgare L.)) to help farmers and water authorities achieve higher yields and a more sustainable use of water resources. The typical meteorological year (TMY) methodology combined with the MOPECO model were used to: (1) determine the distribution of wet, intermediate, and dry years during the growing cycle of the four selected crops; (2) determine the average (AVE) and typical irrigation requirements of these crops for the complete 70 years series (TMYG) or the duration of the crop cycle (TMYC), and under wet (TMYW), intermediate (TMYI), and dry (TMYD) year conditions; and (3) recommend the irrigation depths to be used for the management of farms and water bodies. The results show that the number of wet, intermediate, and dry years depends on the growing cycle of the crop considered, with wet years being unusual, although they notably increase the average rainfall in the area. The irrigation requirements for the average year were between 20.4 and 9.0% lower than the average irrigation requirements calculated for the four studied crops during the 70 years of the series. For western Mancha farmers the recommended irrigation depth for dry years and most profitable crops (garlic and onion) is the one calculated for the driest year of the series, while for the rest of the years and crops is that estimated by the global dry TMY (TMYGD). For eastern Mancha farmers the recommended irrigation depths are also those estimated by the TMYGD.

Quality and hydrochemical assessment of groundwater in geological transition zones: a case study from N.E. Nigeria.

Sustainable management of groundwater resources in geological transition zones (GTZ) is essential due to their complex geology, increasing population, industrialization, and climate change. Groundwater quality monitoring and assessment represent a viable panacea to this problem. Therefore, there is a great need to investigate groundwater resources in terms of their chemistry and pollution to ascertain their quality and implement robust pollution abatement strategies. This study focused on the characterization of groundwater in a typical geological transition zone in northeastern Nigeria. Eighty-seven (87) groundwater samples were collected from dug wells and boreholes during the 2017 dry season. pH, conductivity, and total dissolved solids (TDS) were measured in situ using a multiparameter probe, while major cations and anions were measured using atomic absorption spectrometry and ion chromatography, respectively. Data were analyzed using descriptive statistics, principal component analysis (PCA), water quality index, and standard hydrochemical plots. TDS ranged between 95 and 1154 mg L-1 in basement terrains and between 49 and 1105 in sedimentary areas. pH ranged between 6.8 and 7.7 mg L-1 in basement terrains and between 5.0 and 6.5 in sedimentary areas, suggesting a moderately acidic to alkaline low mineralized groundwater. Calcium (2.6-128.0 mg L-1) was the dominant cation in the basement areas, suggesting silicate weathering/dissolution, while sodium (1.9-106.0 mg L-1) dominated the sedimentary zones due to base exchange reactions. The PCA analysis suggests that mineral dissolution (mostly silicate weathering) controls the hydrochemistry of the basement aquifers, while ion exchange and albite weathering, with some influence of anthropogenic factor, control the sedimentary aquifers. The water quality index revealed that the basement setting was predominated by poor to unsuitable groundwater, while the sedimentary terrain was characterized by potable groundwater. The dominant hydrochemical facie in the basement areas was Ca2+-(Mg2+)-HCO3- characteristic of recharge meteoric water. The Na+- (K+)-HCO3- facie characterized the sedimentary zones, indicative of cation exchange reactions, while the mixed water facie typifies the geological contact zones. The shallow nature of the basement groundwaters makes them more susceptible to geogenic and anthropogenic pollution compared to the sandstone aquifers. However, the basement aquifers have better irrigation indices (Kelly ratio and soluble sodium percent) as compared to the sandstone aquifers, which exhibit poor Kelly ratios (< 1) and soluble sodium percent (> 50) ratings. Results from the study clearly highlight the poor-unsuitable groundwater quality in parts of the studied GTZ and can be very instrumental to the policymakers in implementing sustainable water treatment strategies and cleaner production technologies in GTZ to forestall the incidence of water-related diseases.

Reducing uncertainty of karst aquifer modeling with complementary hydrological observations for the sustainable management of groundwater resources

• We propose a lumped model to simulate a strategic karst aquifer under management. • Parameter estimation is conducted on multiple surface and groundwater data types using a Monte-Carlo procedure. • Parametric uncertainty is greatly reduced when hydrological surface discharge observations are introduced in the parameter estimation process. • We estimate a tipping point between sustainable and unsustainable management as a decision key for stakeholders. A quantitative estimation of the sustainability of groundwater resources is a challenge for water supply in most regions of the world. Sustainability can be estimated through numerical simulation, but uncertainty of models somehow limits the reliability of models’ predictions. To overcome this limitation, we explore how parametric and predictive uncertainties is reduced by adding complementary groundwater and surface water dynamics data to a lumped parameter model. This is illustrated with the example of a Mediterranean karst hydrosystem pumped at high flow rate (∼1 m 3 s −1 ) to supply water to about 350,000 habitants. A lumped parameter model was set up to simulate spring discharge, water table levels and surface water discharge measured within this karst hydrosystem over a 40 year period. Then, a parameter estimation and uncertainty quantification, based on groundwater discharge, water table levels and surface water discharge observations, was conducted with a Bayesian approach. Our study illustrates how the consideration of complementary hydrological data allows reducing parametric and predictive uncertainty and improving model performance. The model is then applied to assess the impact of an increasing groundwater abstraction according to different prospective scenarios, with a focus on the storage and dynamic of flux between the different compartments of the karst hydrosystem. Based on simulation results and related predictive uncertainty, a groundwater abstraction threshold, which must not be exceeded for a sustainable management of the groundwater resource, is determined.

Contribution of the fuzzy algebraic model to the sustainable management of groundwater resources in the Adamawa watershed

Study regionThe study area is located between longitudes 11–16° E and latitudes 6–8° N in the heart of Central Africa. The Adamawa Plateau is a junction watershed for Cameroon and its neighboring countries. It plays an important hydrogeological role at an international level as it hosts transboundary aquifers extending from the Federal Republic of Nigeria to the Central African Republic on a total area of 6700 km2. It is so-nicknamed the "water tower" of Central Africa. Study focusBecause of the failure of the water supply system in the region, households, the local population, and regional authorities are exploiting groundwater resources. Unfortunately, an important number of wells and boreholes are reported to be unproductive because of the nonexistence of preliminary hydrogeophysical investigation. Such investigations are expensive, time-consuming, and require cut-edge technology and expertise. The present study focuses on the assessment of groundwater potential (GWP) throughout the Adamawa region to identify localities with important water yields New hydrological insights for the regionContrarily to the previous investigations conducted in the region, this study uses the fuzzy algebraic model to combine six hydro-parameters contributing to groundwater occurrence in a GIS environment to assess GWP. As a result, the region is classified into four suitability levels: high, moderate, low, and null covering 54.76 %, 31.66 %, 12.24 %, and 1.32 % of the total study area respectively

Status of Groundwater Aquifers, Water Quality, Sources of Contamination, and Future Challenges in Bangladesh: A Comprehensive Review

The groundwater resource of Bangladesh is under increasing threat from population growth, over-water mining, quick urbanization, and pollution from industrial events with domestic and agricultural activities. The objective of this paper is to review over a hundred well-recognized national and international journals, conference proceedings, reports, and other related documents on the status of groundwater aquifers, water quality, sources of contamination, and future challenges in Bangladesh to develop sustainable groundwater resource management. The study observed that groundwater in several zones in the country has been contaminated with elevated levels of dissolved elements. Temporary hardness in countrywide groundwater was found in higher ranges for all purposes while except for bicarbonate, all anions did not cross the guideline value. Among the metal contaminants, arsenic found in the shallow aquifer at an alarming level throughout the country threatened public health, and millions of consumers are suffering from severe and chronic poisoning from arsenic riches water. Additionally, climate change and sea-level rise are likely with increasing salinity and various nutrient concentrations in the coastal aquifer systems of the country, and that water is not fit for domestic and agricultural uses.

Delineation of groundwater potential zones of upper Godavari sub-basin of India using bi-variate, MCDM and advanced machine learning algorithms

Sustainable management of groundwater resource is a most critical due to its over exploitation and ascending stress by industrial and socio-economic factors. It is utmost important to manage this precious resource by properly identifying the suitable Groundwater Potential Zones (GPZ). Therefore, the main aim of the present study is to delineate the GPZ in the upper Godavari sub-basin of India by employing different bi-variate, Multi Criteria Decision Making (MCDM), ensembled, and Machine Learning (ML) models. These models include Weight of Evidence (WoE) (bi-variate), Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) (MCDM), Fuzzified Functional Ratio (F-FR) (bi-variate), Extreme Gradient Boosting (XGB) (ML) and Extremely randomized Trees (ET) ML. The ensembled model featured different combination of WoE, TOPSIS and F-FR for mapping the enhanced accuracy in predicting the GPZ. A total of 15 groundwater factors were considered where 75% of the data were selected as training data and the rest 25% as validation data. These data were used to produce the ensembled ML models. The result of the model was plotted in terms of area under curve (AUC)-Receiver Operating Characteristics (ROC) curve and selected best model. The AUC-ROC result of the obtained model was found to be WoE oE models. The result of the model was plotted in termWoE_TOPSIS = 94%, WoE_F-FR = 93%, TOPSIS_F-FR = 94% and WoE_TOPSIS_F-FR = 95%. Results clearly indicate the improved accuracy of ensembled bi-variate and MCDM model over advanced ML model. The predicted statistical properties of the ensembled model also resembled ML models and a high correlation was observed. Thus, the ensembled model can be used over advanced ML models for delineating the GPZ mapping.

Hydrochemical Characteristics and Quality Assessment of Groundwater under the Impact of Seawater Intrusion and Anthropogenic Activity in the Coastal Areas of Zhejiang and Fujian Provinces, China

Abstract Coastal groundwater is an important resource in the developed region associated with human health and sustainable economic development. To identify the origins of salinity and evaluate the impact of water-rock interactions, seawater intrusion (SWI), and evaporation on groundwater in the coastal areas of Zhejiang and Fujian provinces, a comprehensive investigation was performed. Meanwhile, nitrate and fluoride indicators resulting from the anthropogenic activity and SWI were also considered. At last, the water quality index (WQI) of coastal groundwater was evaluated with geochemical and multivariate statistical methods. The results indicated that (1) the groundwater in coastal areas of Zhejiang and Fujian provinces has been affected by SWI to varying degrees. The analysis of selected ion ratios (Na+/Cl− and Br−/Cl−) and isotopic compositions showed that SWI is the predominant cause of increasing salinity in the groundwater of Zhejiang Province, while the cause is water-rock interactions (ion exchange and mineral weathering) in Fujian Province. The hydrochemical evolution path of groundwater in Zhejiang Province is Ca/Mg-HCO3 to Na-Cl, while a different pattern of Ca/Mg-HCO3 to Na (Mg/Ca)-Cl occurs in Fujian Province. However, the trend of SWI development in both provinces was freshening. (2) Nitrification, sewage infiltration, and SWI increased the NO3− content in groundwater. Some of the NO3− concentration in Fujian Province exceeds the standard, and the nitrogen pollution was more serious than in Zhejiang Province. The F− content in coastal groundwater was affected by SWI and mineral dissolution; the F− content in Zhejiang Province was higher than in Fujian Province, which was close to the groundwater standard limit. The average WQI value of Zhejiang was 103.61, and the WQI of Fujian was 61.69, indicating that the coastal groundwater quality in Fujian Province was better than in Zhejiang Province. The results of the study revealed the impact of SWI and anthropogenic activity on groundwater in the southern coastal zone of China and will be valuable for sustainable groundwater resource management.

Delineation of Groundwater Potential Zones (GWPZs) in a Semi-Arid Basin through Remote Sensing, GIS, and AHP Approaches

Groundwater occurrence in semi-arid regions is variable in space and time due to climate patterns, terrain features, and aquifer properties. Thus, accurate delineation of Groundwater Potential Zones (GWPZs) is essential for sustainable water resources management in these environments. The present research aims to delineate and assess GWPZs in a semi-arid basin of San Luis Potosi (SLP), Mexico, through the integration of Remote Sensing (RS), Geographic Information System (GIS), and Analytic Hierarchy Process (AHP). Seven thematic layers (geology, lineament density, land use and land cover, topographic wetness index (TWI), rainfall, drainage density, and slope) were generated in raster format. After the AHP procedure and rank assignment, the thematic layers were integrated using the raster calculator to obtain the GWPZs map. The results indicated that 68.21% of the area is classified as low groundwater potential, whereas 26.30% is classified as moderate. Validation was done by assessing the water residence time data from 15 wells distributed in the study area. Furthermore, the Receiver Operating Characteristics (ROC) curve was obtained, indicating a satisfactory accuracy prediction (AUC = 0.677). This study provides valuable information for decision-makers regarding the conservation and sustainable management of groundwater resources.

Identification of Groundwater Potential Zone in Poondi Microwatershed, Thiruvallur, Tamil Nadu

Abstract Water is essential for all living organisms, but in recent years groundwater is declining due to various manmade activities. The rainwater received during the monsoon season does not fully infiltrate into the ground because of varying land type, flow type, flow direction, and environment. In the present study geographic information system (GIS) was used to identify groundwater potential zones in Poondi micro watershed, Thiruvallur district in Tamil Nadu. The various maps are prepared using ArcGIS tool show, variation in slope from high to low, land use/ land cover, lithology, lineament density, geomorphology, drainage density, rainfall and soil type. The analytical hierarchy process (AHP) was used to give a rank and weightage for the all the created maps and every single characteristic in the map. ArcGIS overlay analysis have been carried out based on the assigned weight for different layers of map including geomorphology, slope, soil, land use &amp; land cover, digital elevation model (DEM), lineaments, lithology. From the results of the analysis, the watershed was classified into five Groundwater Potential Zones(GWPZ) namely very good, good, moderate, low, and poor that and may be used for better planning and sustainable management of groundwater resources.

Artificial recharge endeavours in India: A review

In India, artificial recharge (AR) of aquifers is considered a primary supply-side measure to combat the widespread over-exploitation of groundwater. As a major collateral benefit of rainwater harvesting (RWH) is aquifer rejuvenation, both rainwater harvesting and AR are planned and executed as a set of coherent interventions. The Central and state governments have brought in several schemes involving AR and RWH. Moreover, a number of researches are being conducted on how to select the sites for structure construction, the types of structure and their designs depending upon the local hydrogeology, groundwater flow regime, terrain condition and demand of water, and how they impact on resource rejuvenation and improvement in water quality. Various researches are also available on how such endeavors are translating into socio-economic benefits. The paper reviews the researches that have been done in India on these issues and related government policies and schemes under execution. The critical issues like source water availability for recharge, upstream-downstream conflicts, and the rising awareness of different demand-side interventions for sustainable management of groundwater resources have also been discussed.