Groundwater Exploitation Research Articles

Integrated approach to water resource management in Mashhad Plain, Iran: actor analysis, cognitive mapping, and roadmap development.

Iran's Mashhad Plain faces a severe water crisis due to the excessive exploitation of groundwater, leading to the depletion of its aquifer. While water demand management is recognized as a superior solution compared to supply projects, its implementation presents notable challenges. This study addresses the urgent necessity to curtail water demand in the Mashhad Plain by alleviating conflicts among various stakeholders, including water resource managers and consumers. Initially, the research identifies key water resource actors who collaborate in devising a comprehensive roadmap and conceptual model for efficient water resource management. An analysis uncovers significant conflicts among actors, representing approximately 6% of identified issues, with minor conflicts in 30% of cases. Encouragingly, stakeholders demonstrate potential for consensus on the remaining conflict items, with specific actors emerging as pivotal in conflict resolution. Efficient water resource management in regions facing scarcity, diverse interests, and sustainability challenges demands a multifaceted strategy. Future endeavors involve developing a dynamic system model to simulate policy impacts and strengthen conflict resolution efforts. This research introduces a roadmap-driven approach aimed at resolving conflicts and implementing water demand management in the Mashhad Plain. It emphasizes the critical need to address water scarcity challenges while effectively mitigating conflicts among water resource stakeholders.

InSAR time series analysis of natural and anthropogenic coastal plain subsidence: A case of Hangjiahu plain

The early excessive groundwater exploitation caused extensive land subsidence in the Hangjiahu Plain (HJHP), threatening geological stability and infrastructure. Government restrictions on groundwater exploitation led to considerable changes in surface subsidence. To explore the distribution and causes of surface deformation after restrictions on groundwater exploitation, we used 46 Sentinel-1A TOPS images to detect the spatiotemporal distribution of surface deformation in the HJHP area from January 2019 to October 2022 by SBAS-InSAR technique and verified it with leveling results. Results indicated the following: (1) The uneven surface subsidence in the HJHP was relatively apparent, with the localized subsidence concentrated in a few areas. During InSAR monitoring, the maximum subsidence velocity reached −21.0 mm/yr. The most severe subsidence area was in the Shengze town industrial park, with remarkable subsidence bowls and a maximum subsidence of −85.8 mm. (2) Results were verified by comparing the InSAR results with leveling, and the results were in good agreement, indicating the reliability of the InSAR results. (3) Comprehensive analysis of the spatial distribution characteristics of surface subsidence, geological data and rainfall changes revealed that fault activity and rainfall changes had varying degrees of effect on surface subsidence in the HJHP area. (4) The comparison with land use data indicated that the built area was the dominant mechanism of surface subsidence in the study area. In addition, the effect of industrial activities on the surface cannot be ignored. The study results provide scientific data support for emergency disaster prevention work in the HJHP.

Estimation of Groundwater Storage Change and Groundwater Recharge Using GRACE data in Jedeb Watershed Under the Application of Google Earth Engine

Over exploitation of Ground Water (GW) has resulted in lowering of water table in the Jedeb watershed. In this study, water storage changes with GRACE satellite data and total annual precipitation with CHIRPS data in the Google Earth Engine system were investigated for the Jedeb watershed during 2003–2017. The groundwater recharge is estimated from a time series of groundwater storage using the water table fluctuation method. According to the results obtained from the GRACE satellite data on the fluctuations of annual water storage between 2003 and 2017, it was found that the biggest annual increase in water levels (15 cm) occurred in 2008, 2013, and 2015, and the biggest annual decrease (12.5 cm) occurred in 2012. The obtained net recharge rate varied from 18 to 25 cm/year for a 14-year period, and the average was 21 cm/year. This study indicates that the GRACE-based estimation of groundwater storage changes is skilled enough to provide monthly updates on the trend of groundwater storage changes for resource managers and policymakers in the Jedeb watershed.

Smart water: An innovative approach to integrated water management at the Faculty of Sciences Ben M’sick (Casablanca, Morocco) in the face of water stress

The integrated management of water resources at the level of various human activities is today imperative for individuals and organizations. This study investigates the possibilities of applying a responsible and sustainable water management approach at the Ben M’sik Faculty of Sciences (FSBM) in Casablanca through rainwater collection/reclamation, groundwater exploitation and decentralized treatment/internal wastewater reuse. To this end, physicochemical characterization of these three types of water was carried out, with preliminary results showing that the wastewater quality complied with the discharge limits recommended by Lydec for all the parameters determined, except for Chemical Oxygen Demand (COD) and Total suspended solids (TSS), with average values for COD, BOD5, and TSS of around 1010.12 mg L -1, 87.27 mg L-1 and 370.48 mg L-1 respectively. In parallel, average values for COD/BOD5 (33.19), TSS/BOD5 (6.03) and oxidizable matter (360.72 mg L-1) revealed that these wastewaters are heterogeneous and poorly biodegradable. As for rainwater and groundwater, the results show that they comply with the quality grid for water intended for irrigation, except for chloride (715.23 to 884.72 mg L-1) and nitrate for groundwater (61.45).

Assessment of Groundwater Recharge and Groundwater Quality in The Upstream of Tondano Watershed, North Sulawesi, Indonesia

Raw water need increases along with the development of a region. In terms of quantity and quality, surface water tends to decrease, which causes an increase in groundwater exploitation. For groundwater in the Tondano watershed to be sustainable and meet the required quality standards, it is necessary to know about groundwater recharge and groundwater quality. This study’s objectives are to calculate groundwater recharge using a simplified groundwater balance and to evaluate groundwater quality using physico-chemical parameters. The method used in this study is to estimate groundwater recharge by calculating groundwater balance using data on annual rainfall, annual evapotranspiration, and annual runoff. Meanwhile, for groundwater quality, Physico-chemical properties were measured, including pH, TDS, EC, and temperature, at 21 measurement points, including springs, dug wells, and drilled wells. The results indicate that groundwater recharge calculation shows a positive value of 318.34 mm/year. The measurement of Physico-chemical parameters in the field suggests that the pH value is in the range of 6.1-7.9, the TDS range is 50-200 mg/L, the EC range is 110-400 μs/cm, and the temperature range is 23.4-35.6 °C. The analysis using World Health Organization standards and Ministry of Health standards show that the groundwater quality is suitable for use.

Eastern Region Holds the Key to Future Increase in Rice Production in India

Rice is the main staple food of India and supply of adequate amounts of rice to the consumers is essential to ensure food security. However, rice production in recent years has been threatened by unsustainable use of groundwater and yield plateauing in irrigated areas. The objective of this paper is to find out the regions that face such problems and recommend strategies to overcome them. Data for this study was gathered from various ministries of the Government of India. Analyses of data reveal that the eastern region accounts for 50% of India’s rice production, and holds 56% of the total rice area. The region receives more rainfall than the northern, southern, and western regions states. The groundwater exploitation is below 50% in the region. The demonstrations carried out by two mega schemes of the government of India show potential for increasing rice productivity in the eastern region. It was observed that the groundwater has been overexploited in northern and southern region states viz. Punjab, Haryana, and Tamil Nadu. Yield plateauing was also observed in five irrigated states in recent years. Various strategies are discussed to overcome the problems, adoption of yield-enhancing and water-saving technologies, and the promotion of rice cultivation in eastern states.

Groundwater Quality Monitoring in Response to Marine Intrusion: A Case Study in Northern Morocco

Water stress, resulting from a demand for water exceeding the available quantity, is a major global challenge. Groundwater usage is a commonly adopted strategy to address this situation, but it often leads to marine intrusion, threatening the quality of water in coastal aquifers. This phenomenon typically stems from overexploitation of aquifers, declining water table levels, and rising sea levels due to climate change. Our study aims to monitor the quality of groundwater intended for human consumption and provide a detailed assessment of its current state. We identified several physicochemical parameters, such as temperature, pH, and bicarbonates, with maximum electrical conductivity values reaching 2810 µs/cm, a total hardness of 21 meq/L, sulfate levels of 689 mg/L, and chloride levels of 628 mg/L, from six boreholes and one well located along the coastal area of the Al Hoceima region. These samples were also subjected to Principal component analysis (PCA) of the chemical parameters, revealing two factors that represent approximately 62.15% of the total variance in the groundwater quality dataset. Simulation results indicate signs of seawater intrusion in several areas, particularly near the coast, emphasizing the urgency of protecting groundwater resources and developing sustainable management strategies to ensure a safe and reliable supply of drinking water in the region.

УСТОЙЧИВОСТЬ ЗДАНИЙ И СООРУЖЕНИЙ ЗАПОРОЖСКОЙ АТОМНОЙ ЭЛЕКТРОСТАНЦИИ ПРИ ИСПОЛЬЗОВАНИИ АРТЕЗИАНСКОЙ ВОДЫ ДЛЯ ТЕХНОЛОГИЧЕСКОГО ПРОЦЕССА СТАНЦИИ

The article provides an assessment of ensuring safe operation, water supply, as well as the safety of personnel and the environment during the operation of the Zaporizhia NPP. It has been established that the exploitation of groundwater for the technical water supply of the NPP and its infrastructure facilities, both under constant and periodic drainage regimes, will lead to the formation of depression funnels, the size of which will depend on the magnitude (flow rate) of the water intake, the layout of water intake facilities and specific hydrogeological conditions of the groundwater deposit. It is shown that it is necessary to ensure not only the strength of the soils under the structures of buildings and structures of nuclear power plants, but also the reliable functioning of all systems that control the nuclear process. The necessity of monitoring the stability of geological and geophysical conditions in the area and at the sites of nuclear power plants in the monitoring mode has been determined. The monitoring is comprehensive. It includes geotechnical, surveying and geodetic, hydrogeological, and seismological observations. The forecast of the development of a depression funnel in time and space should be carried out by analytical methods or modeling, taking into account changes in the conditions of the relationship of aquifers with each other and environmental components. It has been revealed that extending the further operation of the NPP is an expensive and unsafe process. It is not possible to upgrade old power units to modern ones in terms of safety in nuclear energy. The power units of the Zaporizhia NPP are not ready for further operation, therefore, it is necessary to start developing a project for decommissioning power units No. 1-4 of the NPP.The research results can be useful in predicting the possible development of karst-suffusion processes under the influence of intensive groundwater drainage, organizing monitoring of the possible development of these processes, including them in the integrated monitoring of this facility. It will make it possible to justify the scale and regime of rational water extraction, taking into account the requirements for environmental protection and the specifics of further operation of the NPP.

Identification of potential groundwater sources using Electrical Resistivity Imaging (ERI) method in Jambu Lawar, Machang, Kelantan

The study area is primarily composed of volcanic rock and plain quaternary sediment. Extrusive and intrusive rocks are the two varieties of igneous rock that have been found. In the examined location, igneous intrusive rock, specifically biotite granite, makes up most of the rock formation. Grey to white colour, biotite granite has a phaneritic, coarse- grained texture. On the other hand, andesite, an igneous extrusive rock, makes up the minor rock formation. The study aims to identify the potential groundwater resources of the study area. Groundwater viability is examined using the Electrical Resistivity Imaging (ERI) method. Each of the survey lines extends over a length of 200 meters, incorporating 41 takeouts positioned at 5m spacing, and adopts the Schlumberger array electrode configuration. Both surface water and groundwater are essential resources in Kelantan for daily life; nevertheless, ongoing groundwater exploitation causes depletion. This potential is defined by low resistivity materials that can store large amounts of groundwater. As biotite granite is inherently unsuitable for groundwater collection between grains, possible fracture zones are highlighted as likely sites for groundwater presence. The 2D pseudosection results for all three survey lines emphasize a substantial accumulation of groundwater in a spatially expansive zone. This is because the resistivity value for all the survey lines is below 100 Ωm.

Assessing rainwater quality in Ca Mau Province: Unveiling the potential and viability for domestic usage

The potential for exploiting rainwater in Ca Mau Province is immense due to its average annual rainfall of 1772 to 2500mm. Over a 15-year continuous monitoring period, the analysis of rainwater quality in Ca Mau Province reveals a prevailing alkaline tendency, with an average pH of 5.90, well within the established raw water quality standards. Concurrently, ongoing groundwater exploitation activities pose a significant threat to the natural aquifer reserves in the region. Recognizing this challenge, rainwater harvesting emerges as a pivotal strategy to alleviate the strain on groundwater extraction. The accumulation of freshwater during the rainy season in Ca Mau, facilitated by household rainwater storage tanks, offers a sustainable solution, ensuring a readily available supply for drinking and cooking needs during the dry season when rainfall is scarce. In addition, average tank capacity to meet the domestic water demand of a 5-member household is 10m3 for the whole year while this number increases to 18 20m3 during the dry years. These rainwater stored in tanks should be treated with chlorine or UV rays before use. Our study provides valuable evidence for policy makers and managers, based on the case study at Ca Mau, to develop a sustainable rainwater management plan for improving the livelihoods of millions people lacking freshwater in coastal zones of the Vietnamese Mekong Delta.

Understanding Consumer Choices: Towards Sustainable Water Use in India

This study addresses the pressing issue of water scarcity in India, focusing on sustainable water management and the crucial role of consumer behavior. It establishes a clear correlation between safe water access, economic development, and public health, emphasizing the interconnectedness of these factors. The concept of a water footprint, comprising green, blue, and gray components, provides a framework for analyzing global water usage. The socio-economic context highlights the significance of recognizing water as an economic good for efficient resource allocation. Global water availability is discussed, revealing the inadequacies in freshwater distribution and the widening gap between demand and supply. India's precarious position, given its large population, is underscored. Issues related to water consumption, including reckless groundwater exploitation, emphasize the need for stakeholder involvement and a paradigm shift in water management. The study stresses the urgency of an action plan for sustainable water management, advocating strategies such as storage, conservation, and recycling. Disproportionate water usage in agriculture and urban inefficiencies are addressed, urging modernization and technological advancements. Public engagement emerges as pivotal, with consumer behavior significantly impacting water usage patterns. The study discusses the role of public feedback "report cards" in promoting accountability among service providers, whether private or government-owned. Highlighting growing awareness in India, referencing NITI Aayog's Composite Water Management Index, the study emphasizes the disparity between population and freshwater resources. Groundwater depletion and per capita water use statistics underscore the need for immediate action. The study explores untapped water supply sources, advocating for the reduction of system leakage and promoting rainwater harvesting. The potential of stormwater and wastewater management is discussed, emphasizing the importance of incorporating green infrastructure solutions. In conclusion, the study underscores the significance of studying consumer behavior to enhance water conservation strategies. Recommendations include assessing consumer awareness, understanding utilization patterns, and perceptions affecting economic impact. The research advocates for a paradigm shift in water use and recycling, emphasizing the critical role of consumers in shaping a sustainable water future for India.

Precipitation Assessment of Kabul City from 2006-2020

Assessment of precipitation conditions is a crucial factor in determining an area's current and future climatic conditions. This study investigates precipitation conditions in Kabul City from 2006 to 2020, covering the last 15 years. Research shows that 50% of precipitation occurs in the winter season in Kabul and varies from year to year. The trend line of precipitation has shown a minimal increase of 0.64mm/yr, which is insufficient due to the dense urban population's high-temperature increase and daily water usage. The study aims to assess the precipitation conditions in Kabul for the past 15 years. For this purpose, climatic data from the Afghanistan Meteorological Department (AMD) and daily precipitation data were analyzed. Standard deviation equations were applied to determine the dry and wet years from the average (normal) year. The analysis of the precipitation data demonstrated two periods of severe droughts and one moderate rainy period. The first severe drought occurred from 2007 to 2008, the second period of severe drought occurred from 2016 to 2018, and one moderate rainy period occurred from 2011 to 2014. The results indicate that Kabul City's precipitation is not enough due to the usage of groundwater by the dense urban population, car wash companies, public baths, and the recent establishment of too many greenhouses in the suburbs of Kabul City. Consequently, the water balance is negative, leading to a shortage. Understanding the precipitation condition of Kabul City and its trends over the past 15 years is crucial for policymakers and stakeholders when making decisions on water resources management, agriculture, food production, and environmental challenges incorporation projects. This research provides valuable information that can support evidence-based decision-making to address the challenges posed by the changing climate patterns in Afghanistan.

Influence of South-to-North Water Diversion on Land Subsidence in North China Plain Revealed by Using Geodetic Measurements

As a major grain-producing region in China, the North China Plain (NCP) faces serious challenges such as water shortage and land subsidence. In late 2014, the Central Route of the South-to-North Water Diversion Project (SNWD-C) began to provide NCP with water resources. However, the effectiveness of this supply in mitigating land subsidence remains a pivotal and yet unassessed aspect. In this paper, we utilized various geodetic datasets, including the Gravity Recovery and Climate Experiment (GRACE) and GRACE Follow On (GRACE-FO), Global Navigation Satellite System (GNSS) and leveling data, to conduct a spatial-temporal analysis of the equivalent water height (EWH) and vertical ground movement in the NCP. The results reveal a noteworthy decline in EWH from 2011 to 2015, followed by a slight increase with minor fluctuations from 2015 to 2020, demonstrating a strong correlation with the water resources supplied by the SNWD-C. The GRACE-derived surface deformation rate induced by hydrological loading is estimated to be <1 mm/yr. In comparison, GNSS-derived vertical ground movements exhibit considerable regional differences during the 2011–2020 period. Substantial surface subsidence is evident in the central and eastern NCP, contrasting with a gradual uplift in the front plain of the Taihang Mountains. Three-stage leveling results indicate that the rate of subsidence in the central and eastern plains is gradually increasing with the depression area expanding from 1960 to 2010. Based on these geodetic results, it can be inferred that the SNWD-C’s operation since 2014 has effectively mitigated the reduction in terrestrial water storage in the NCP. However, land subsidence in the NCP persists, as the subsidence rate does not turn around in sync with the change in EWH following the operation of SNWD-C. Consequently, it’s necessary to maintain and enforce existing policies, including controlling groundwater exploitation and water resources supply (e.g., SNWD-C) to curtail the exacerbation of land subsidence in the NCP. Additionally, continuous monitoring of land subsidence by GRACE, GNSS, leveling and other geodetic techniques is crucial to enable timely policy adjustments based on monitoring results.

Predicting the Planting Time of Bird's Eye Chili Based on Environmental Conditions Using Internet of Things (IoT) and Neural Network Method

In Indonesian cuisine, the red Tabasco pepper holds a significant place as a commonly used ingredient. However, the cultivation of this chili variety is not without its challenges, primarily due to the volatile nature of the chili prices. Farmers often struggle with the critical decision of when to plant Tabasco peppers to optimize their yields and income. Understanding the complexities of this decision-making process in the context of varying environmental conditions is crucial. Thanks to recent advances in Internet of Things (IoT) technology, innovative systems have emerged to address these challenges.This study focuses on the development of an IoT-based solution aimed at helping farmers in precisely determining the optimal planting time for Tabasco pepper. It uses five key criteria—average temperature (°C), average humidity (%), rainfall (mm), length of sunlight (hours) and groundwater usage data (m3) to make data-driven planting decisions. The urgent need for such a system becomes evident when considering the unpredictability of climate patterns and their direct impact on crop outcomes. Using historical data from 2019, obtained from the Jakarta Provincial Government Open Data DKI, and climate data from the Meteorological Agency, Climatology, and Geophysics (BMKG), the authors have successfully developed an IoT-based prototype. This prototype employs a neural network algorithm to analyze the aforementioned criteria. The result is a reliable prediction system that boasts an impressive accuracy rate of 91.26%. By offering this level of precision in determining the ideal planting time for Tabasco pepper, the system extends invaluable support to farmers, helping them optimize their cultivation practices and navigate the uncertainties of the chili market.

Investigating the association between floods and low birth weight in India: Using the geospatial approach

BackgroundFrequent natural disasters like floods pose a major threat to India, with significant implications for public health. Low birth weight (LBW) is a critical global health concern, contributing to neonatal mortality. However, the association between floods and LBW remains underexplored. This study aims to address this gap by investigating the association between flood hazards and LBW in India using a geospatial approach. By analyzing data from the National Family Health Survey (NFHS-5) and flood zonation maps, the study aims to uncover the spatial dynamics of this association, offering insights into the implications of floods on birth weight across diverse geographical regions. MethodsThe study used the fifth round of NFHS data, 2019–21, which involved 202,194 children selected through a multi-stage stratified sampling technique. The Vulnerability Atlas of India 2019 maps were also utilized to classify areas as flood or non-flood zones. Birth weight data from the NFHS-5 were categorized into three groups: very low, low, and normal birth weight (VLBW, LBW and NBW). Control variables including flood exposure, socio-demographic attributes, and geographic region were considered. Bivariate analysis and multinomial logistic regression were employed for statistical analysis. The spatial analysis involved Moran's I statistics and Geographically Weighted Regression to explore spatial dynamics of the association between floods and birth weight in India. ResultsFloods predominantly affect India's lower Himalayan belts and western coastal regions. Flood-affected areas show higher proportions of VLBW and LBW infants. Groundwater usage and unimproved sanitation are associated with higher risk of VLBW and LBW. Sex, wealth, maternal education, residence type, and geographic region significantly influence birth weights. Multinomial logistic regression reveals 8 % and 27 % higher risks for LBW and VLBW in flood-affected regions. LISA cluster maps identify high-risk areas for both LBW and floods. Geographically Weighted Regression highlights 52 % of the variability in LBW occurrences can be attributed to the influence of flood hazards. Families hailing from the poorest wealth background and exposed to flood hazards bear a 5 % heightened likelihood of delivering LBW infants, in stark contrast to their counterparts from the same economic background yet unaffected by floods. ConclusionsThe significant association between floods and LBW underscores the importance of robust disaster preparedness and public health strategies. By unraveling the spatial intricacies of flood-induced LBW disparities, this research provides valuable insights for promoting healthier birth outcomes and reducing child mortality rates, particularly in flood-prone regions. These findings emphasize the importance of holistic policies that address both environmental challenges and socioeconomic inequalities to safeguard maternal and infant health across the nation.

Real-time karst groundwater monitoring and bacterial analysis as early warning strategies for drinking water supply contamination

Karst aquifers have been globally exploited as a reliable source of drinking water but their intrinsic characteristics (concentrated recharge, high groundwater flow velocities, etc.) and the increase of anthropogenic pressures makes them highly vulnerable to pollution. Continuous monitoring of karst springs constitutes an effective approach for identifying episodic groundwater contamination and assuring safety conditions in drinking water supply systems. This study aims to improve groundwater protection insights through an integrated methodological approach based on real-time measurements of continuous water parameters coupled to bacterial analysis for the characterization of contamination events in a carbonate karst aquifer of a mountainous and rural area in S Spain. For this purpose, environmental, hydrodynamic and physico-chemical data in addition to bacterial activity (Escherichia coli) analysis were gathered from the analysis of eight flooding events at the two main outlets. In these karst springs, partially captured for drinking water supply, the recurrent turbid groundwater episodes suppose an important limitation for groundwater exploitation during several days, but also a concerning human health risk. The results revealed the different flow and sediment dynamics and mixing processes which determine the impact of faecal contamination derived from human activities on the karst groundwater drained by each spring. The described processes control the variable influence of allogenic recharge, which provokes notable differences regarding response times and maximum values of turbidity and associated bacterial activity in the investigated outlets. The outcomes of this work highlight the usefulness of the applied methodological framework to set the bases for an efficient implementation of early-warning strategies to prevent public health issues worldwide.

Spatial and Temporal Patterns of Land Subsidence and Sinkhole Occurrence in the Konya Endorheic Basin, Turkey

The endorheic Konya Basin is a vast aggradational plain in Central Anatolia, Türkiye. It occupies a significant portion of Konya Province, covering approximately 50,000 km2. The basin is subjected to intense groundwater withdrawal and extensive agricultural activities with excessive irrigation. These activities have led to human-induced hazards, such as sinkholes and regional land subsidence. Although sinkhole occurrence mainly occurs in the Karapınar area, land subsidence is primarily observed in the central sector of Konya city, with 2 million inhabitants, as well as in various parts of the basin. This study focuses on determining the extent and rate of land subsidence throughout the basin, understanding sinkhole formation, and unraveling their relationship with anthropogenic activities. For this purpose, Interferometric Synthetic Aperture Radar (InSAR) analysis of Sentinel-1 data from 2014 to 2022 was conducted to identify and assess land subsidence. We also used the land cover data and groundwater-level information to better understand the spatial and temporal patterns of land subsidence and sinkhole occurrence. Additionally, the land cover data were used to resolve spatial–temporal variations in the cultivated area and urbanization, which are the main factors governing groundwater exploitation in the region. Our study identified widespread subsidence zones with rates as high as 90 mm/y. Groundwater overexploitation to sustain extensive agricultural operations is the main cause of the high rate of land subsidence. Additionally, it was discovered that the number of sinkholes has substantially increased due to anthropogenic influences, currently amounting to as many as 660.

Evaluation of geohydraulic response properties of hydrogeological units in Littoral hydro-lithofacies in Uyo, Southern Nigeria

Aquifer geohydraulic response properties are important parameters in groundwater resource management and exploitation. However, geohydraulic properties in the study area is sketchy and due to wildcat drilling. This practice, which leads to inadequate inventory of groundwater parameters, deprived the area of efficient exploitation, monitoring and management of groundwater resources. This study is aimed at evaluating the geo-hydraulic response properties of hydrogeological units in littoral hydro-lithofacies in Uyo, Southern Nigeria. Vertical electrical sounding (VES) technique was carried out, and a total of fifteen geoelectric soundings were obtained using IGIS Resistivity metre model SSR-MP-ATS and its accessories employing Schlumberger electrode configuration. The interpreted data give sets of geoelectric curves from which the aquifer resistivity and thickness were determined. The results reveal the aquifer bulk resistivity ranging from 23.4 to 1306.2 Ωm with an average of 347.99 Ωm, while aquifer thickness spanned from 7.4 to 56.3 m. The formation factor, fractional porosity and transmissivity ranged from 2.41 to 12.52, 0.20 to 0.46, and 0.001 to 0.037m2/s, respectively. The formation tortuosity also ranged from 1.05 to 1.58; longitudinal conductance ranged from 0.020 to 1.004 Ω−1; and transverse resistance ranged from 549.90 to 69,097.98 Ωm2. These parameters were contoured, and their variations are displayed on the contour maps generated. The graphs plotted showed strong correlation coefficient and earth response function that can be used in modelling the aquifer repositories in areas with similar geomaterials. The results of this study indicate that the survey area has a good prospect for groundwater accumulation, and the results can be useful in installing matching hydraulic pumps in boreholes in the survey area.

Modelling Groundwater Vulnerability to Contamination using DRASTIC Model through Geospatial Techniques over Northern Kwazulu-Natal, South Africa

This study models groundwater vulnerability to contamination in three northern district municipalities (Amajuba, Zululand and Umkhanyakude) in KwaZulu Natal province in South Africa using GIS-based DRASTIC model. The method considers seven parameters: depth to water table (D), recharge (R), aquifer media (A), soil media (S), topography (T), impact of the vadose zone (I), and hydraulic conductivity (C). DRASTIC parameter maps are generated in ArcGIS environment and relevant weights assigned. A weighted overlay analysis is then employed to generate the groundwater vulnerability map for the study area. Finally, the groundwater vulnerability map is combined with land use/cover to obtain groundwater pollution risk map. Results indicate that 22, 45, 21 and 12% of the total area are under low, moderate, high, and very high groundwater contamination vulnerable zones, respectively. Low, moderate, high, and very high groundwater pollution risk are found in 23, 40, 27 and 10% of the total area, respectively. These results can be used by environmental managers, spatial planers and other policy makers in formulating integrated and sustainable development plans to ensure optimal groundwater exploitation and conservation in the northern KwaZulu Natal region.

Impact of Xiaolangdi Reservoir on the Evolution of Water Infiltration Influence Zones of the Secondary Perched Reach of the Lower Yellow River

Understanding the complex interplay between water management infrastructure and groundwater dynamics is crucial for sustainable resource utilization. This study investigates water infiltration dynamics in the secondary perched reach of the Yellow River after the operation of the Xiaolangdi Reservoir. The methodology included the application of the single-factor analysis of variance and water balance method, alongside a dual-structure, one-dimensional seepage model to simulate interactions within the system, while exploring characteristics of the groundwater flow system and the exploitation depth of below 100 m. Furthermore, we studied the influence zone range and alterations in river water infiltration in the secondary perched reach of the river following the operation of Xiaolangdi Reservoir. The results show that before the operation of the reservoir, the influence ranges of the north and south banks of the aboveground reach extended from 20.13 km to 20.48 km and 15.85 km to 16.13 km, respectively. Following the initiation of the reservoir, the river channel underwent scouring, leading to enhanced riverbed permeability. Additionally, the influence of long-term groundwater exploitation on both riverbanks extended the influence range of groundwater recharge within the secondary perched reach of the river. The influence zone of the north bank is now 23.41 km–26.74 km and the south bank 18.43 km–21.05 km. After years of shallow groundwater extraction, multiple groundwater depression cones emerged within the five major groundwater source areas on both sides of the river. Notably, deeper water levels (Zhengzhou to Kaifeng) have significantly decreased, with a drop of 42 m to 20 m to 15 m. This change in groundwater dynamics extended beyond the main channel of the river, creating a localized shallow groundwater field.