Groundwater Development Research Articles

A Review on Process-Based Groundwater Vulnerability Assessment Methods

The unreasonable development and pollution of groundwater have caused damage to the groundwater system and environmental problems. To prevent this, the concept of “groundwater vulnerability” was proposed, and various evaluation methods were developed for groundwater protection. However, with changing climatic conditions and human activities, groundwater vulnerability is now emphasizing physical processes. This study aims to review and analyze the principles and applications of process-based groundwater vulnerability methods to achieve the source protection of groundwater resources. It introduces the assessment method and elaborates on pollutant migration processes and numerical simulation technology. Relevant articles from the past 30 years are reviewed to show the evolution of process-based groundwater vulnerability assessment. The study also discusses current research trends and proposes future development paths. It concludes that process-based groundwater vulnerability assessment will become the mainstream method, and modern technologies such as artificial intelligence will be necessary to solve challenges and achieve sustainable development.

RQD modeling using statistical-assisted SRT with compensated ERT methods: Correlations between borehole-based and SRT-based RMQ models

In complex tropical granitic terrains, foundation rocks’ bearing strength is important in infrastructure design, while bedrock fractures that adversely impact engineering structures can boost groundwater productivity. Consequently, rock quality designation (RQD) can characterize these features effectively. This technique is difficult to determine in boreholes and relatively costly for a large area. As a result, novel approaches were employed to effectively determine RQD over a large aerial extent using statistically optimized borehole and seismic P-wave velocity (Vp) data with compensated resistivity modeling. This study was carried out in the typical granitic terrain of Penang Island, Malaysia. The first stage involves evaluating and developing borehole-based RQD models, and the results were correlated with Vp data and were regressively analyzed to develop lithology-based empirical relations. These empirical relations were used for developing 2D/3D SRT (seismic refraction tomography) based RQD models and were treated as novel models. Integrating the borehole-based and SRT-based RQD models with compensated resistivity models effectively delineate the surficial-to-subsurface soil-rock profiles based on their rock mass quality (RMQ) and conditions, as residual soil, completely weathered rock, relatively weathered rock, and integral/fresh granitic bedrock, including different directional and multiple axial fractures. Based on these results, the highlighted suitable sections for founding the foundations of infrastructure are pinned on the fresh bedrock at the depths of 8–25 m, with >2400 m/s, >2000 Ω m, and RQD >90%. The deep-weathered/fractured zones, with depth >35 m at localized sections, are water-bearing proposed for groundwater development. Overall, the methods and lithology-based empirical relationships can be adopted in granitic terrains to rapidly estimate RQD for a vast area with few and no borehole data.

Characterization of drinking groundwater quality and assessment of human health risk in Xin’an spring basin, a typical mining and karst area of the northern China

Groundwater is an important natural resources of drinking water in mining area in Xin’an spring basin, northern China. To foster the sustainable development and utilization of groundwater, a total of 332 groundwater samples, including 147 pore groundwater, 95 fissure groundwater and 90 karst groundwater, were collected and hydrochemical parameters were applied to assess the groundwater quality and human health risks caused by oral ingestion. The results showed that the major chemical components of groundwater in Xin’an spring basin were HCO3−, SO42−, NO3−, Cl−, Ca2+, Mg2+, Na+, total hardness (TH), and total dissolved solids (TDS). The contents of TDS, TH, SO42−, NO3−, F−, Fe, Mn, Pb, and As in groundwater were exceed the standard of groundwater quality (SGQ) limits. The main hydrochemical types of groundwater were HCO3-Ca·Mg and SO4·Cl–Ca·Mg. The factors controlling the groundwater chemistry mainly were mineral weathering, evaporation, cation exchange, and anthropogenic input. The results of water quality assessment showed that the karst and fissure groundwater in study area was mainly excellent-good quality water, while pore groundwater was mainly good-medium quality water. The poor and extremely poor quality water was mainly distributed in Changzhi basin, and the greater contribution made by Pb, Mn, NO3−, Fe, SO42−, TH and TDS. The range of hazard index (HI) values of groundwater was 0.28 to 27.79, and the HI values mainly contributed by NO3−, F−, As, ingestion rate (IR) and exposure duration (ED). The cumulative carcinogenic risk (CCR) values ranged from 1.5 × 10–7 to 2.78 × 10–3, and the greater contribution made by Cr, As, Cd, IR and ED. The results of health risk assessment suggested that some parts of the study region may pose a significant non-carcinogenic risk and a high probability in developing cancer to local residents, and infants were at greatest risk to health, followed by children and adults, while teenagers were at least at risk. This study will provide a deeper insight into the water quality situation and geochemical evolution of groundwater in Xin’an spring area, and will assist decision-makers to formulate management strategies of drinking water safety for the study area.

Drought and Groundwater Development

Groundwater is an important freshwater source that satisfies the needs of a significant portion of the world’s population, industries, and ecosystems [...]

A review on Water Resource Planning and Management with Special Reference to Groundwater using Remote Sensing and GIS Techniques

Water is one of the most important natural resources and a physiological necessity to humankind. Freshwater is one of the necessities for the sustenance of life. The use and development of water resources in a sustainable manner is essential in the modern age due to the regular increase in water crises. Remote sensing and GIS techniques are powerful tools for analyzing and manipulating water resource development and management data. GIS technology provides suitable alternatives for the efficient management of large and complex databases. The most significant advantage of using Remote Sensing data for hydrological modeling and monitoring is its ability to generate information in the spatial and temporal domain. Remote sensing and GIS techniques are found efficient to minimize the time, labor, and money and make quick decisions for Sustainable water resources management. Remotely sensed data are most valuable when combined with numerical modeling, geographic information systems, and ground-based information. In short, both these techniques play a significant role in hydrology for water resources development and management. The remote sensing data helps in fairly accurate hydro geomorphological analysis and identification and delineation of land features. The review paper highlights Remote Sensing and GIS techniques and presents a brief review on the application of these two emerging techniques for groundwater resource management and development. Thus, surface investigation of groundwater has proved to be more accessible, time consistent, and cheaper using geomatics technologies.

Land Subsidence in a Coastal City Based on SBAS-InSAR Monitoring: A Case Study of Zhuhai, China

The superimposed effects of sea level rise caused by global warming and land subsidence seriously threaten the sustainable development of coastal cities. In recent years, an important coastal city in China, Zhuhai, has been suffering from severe and widespread land subsidence; however, the characteristics, triggers, and vulnerability assessment of ground subsidence in Zhuhai are still unclear. Therefore, we used the SBAS-InSAR technique to process 51 Sentinel-1A images to monitor the land subsidence in Zhuhai during the period from August 2016 to June 2019. The results showed that there was extensive land subsidence in the study area, with a maximum rate of −109.75 mm/yr. The surface had sequentially undergone a process of minor uplift and decline fluctuation, sharp settlement, and stable subsidence. The distribution and evolution of land subsidence were controlled by tectonic fractures and triggered by the thickness of soft soil, the intensity of groundwater development, and the seasonal changes of atmospheric precipitation. The comprehensive index method and the analytic hierarchy process were applied to derive extremely high subsidence vulnerability in several village communities and some traffic arteries in Zhuhai. Our research provides a theoretical basis for urban disaster prevention in Zhuhai and the construction planning of coastal cities around the world.

Quantitative evaluation of the influence of rainfall changes and groundwater exploitation on the groundwater level: a case study of the northern Huangqihai Basin, China

Abstract Based on the hydrogeological perspective, the variation in the groundwater level (W) was selected as the analysis factor, and the rainfall changes and groundwater exploitation (QGE) were considered to be the influencing factors. The influence of the two factors on W in the northern Huangqihai Basin was analyzed qualitatively and quantitatively. Results showed that both rainfall and QGE showed increasing trends from 1996 to 2020, while the W values decreased. The correlation between QGE and W was weaker in wet years than in normal years but was the highest in dry years. The mutation time was determined to be 2004. Based on the slope-changing ratio of the cumulative quantity method and the elastic coefficient method, it was determined that the contribution of rainfall changes to W was 22.08% and that of QGE was 77.92%. This study highlights the effectiveness of the integration of qualitative analyses and quantitative evaluation for identifying the influence of external factors on groundwater and well documents that the elastic coefficient method can be used in this field. More attention should be focused on the scientific management of QGE to minimize its negative influence on the sustainable development of groundwater.

ANALYSIS OF THE SINKHOLE FORMATION MECHANISM IN PERMAFROST ROCKS IN THE SITE OF INTRAPERMAFROST GROUNDWATER DEVELOPMENT WITH REGARDS OF DISSIPATIVE GEOLOGICAL STRUCTURES

The paper considers hazardous phenomena on the Earth’s surface such as sinkholes within the Lena River floodplain terrace, the Central Yakutia, in the areas of intrapermafrost groundwater development. Possible mechanisms for the formation of a dip based on thermosuffusion and the mechanism of formation of dissipative geological structures are investigated. The materials of monitoring and geophysical works in the areas of manifestation of failures are analyzed.

Regional Specifics of Water Use in the Republic of Belarus

Water management statistics of the state water cadaster of the Republic of Belarus was used to analyze the dynamics of water use over 2000–2019. The study is based on the statistical methods for the analysis of time series and the relative characteristics of water use dynamics. Trends and priorities were revealed in water use in the country as a whole and at the level of administrative regions. It is shown that in 2000–2019, water intake in the country decreased by 28%, and the use of water for drinking and industrial needs dropped by more than 30%. Comparative analysis revealed differences in water use between regions expressed in the relative characteristics: total water intake, the volume of groundwater development and surface water extraction, the amounts of water use for different purposes. In the majority of administrative regions of the country (102 out of 118), the main source of water supply is groundwater, the development of which exceeds the extraction of surface water, and in 36 regions, water supply relies completely on groundwater. The administrative regions are grouped by the priority objectives of water use. It is found that two water use objectives are of priority in 78 regions; these are household and agricultural needs, met by groundwater. The differentiation of the volumes of water withdrawal and water use priorities at the regional level is determined by population size, the development level of material production branches, and their water demand.

Solar Irrigation Potential, Key Issues and Challenges in Pakistan

Pakistan faces water scarcity and high operational costs for traditional irrigation systems, hindering agricultural productivity. Solar-powered irrigation systems (SPIS) can potentially provide a sustainable and affordable solution, but face technical, financial and policy barriers to adoption. A comprehensive study is needed to examine feasibility and identify barriers. Therefore, a comprehensive review study is conducted to identify the potential for solar irrigation, key issues and challenges related to its implementation in Pakistan. The analysis is based on published studies, technical reports and a survey of solar-powered drip irrigation systems. The use of SPIS in Pakistan is becoming a cost-effective and sustainable option for irrigation, particularly in remote and off-grid areas. However, these systems also have their challenges, such as high initial costs, maintenance and repairs, limited access to spare parts, lack of government policies and regulations, lack of technical expertise, lack of financing options and social acceptance. The most pressing issue is the risk of groundwater exploitation by using SPIS. Based on the analysis of the energy and water situation in Pakistan, it is important to sustainably use both solar energy and groundwater resources, through the implementation of effective management strategies and policies. With the right policies and investment in research and development of SPIS and groundwater, farmers can benefit by increasing crop yields, conserving water resources, reducing the cost of energy, increasing productivity and improving the standard of living and access to electricity in remote and off-grid areas. It is recommended that the adoption of solar energy be promoted to run high efficiency irrigation systems (HEIS) with urgent capacity improvement among farmers, advisors and system installers to sustainably manage water resources in SPIS. This would not only help to reduce the consumption of fossil fuels and associated environmental impacts, but also increase farmers’ income and reduce their operational costs. Moreover, the use of SPIS can improve crop yields, leading to food security and poverty reduction. Thus, the government and policymakers should consider implementing policies and incentives to encourage the large-scale adoption of solar energy in the agricultural sector.

Delineation of aquifer promising zones and protective capacity for regional groundwater development and sustainability

Water security is the central mission of the sustainable development goals. The demand for potable and clean water has skyrocketed due to frequent borehole failures and population expansion, which requires adequate groundwater resource management strategies. Identifying groundwater potential zone, overburden protective index capacity and installations of alternative/artificial storage support mechanisms for water security and sustainability under the growing water challenge and demand is critical. This study identifies; (i) aquifer promising zones (ii) aquifer protective capacity through geophysical investigation and suggests (iii) improving aquifer recovery management strategy as the top three targets for groundwater development. An electric resistivity technique was applied to acquire a total of sixty (60) vertical electrical sounding points with Schlumberger arrays. The study indicates the resistivity layer of the aquifer unit ranges from 21 to 294 Ωm, while the aquifer layer thickness values spread from 8 to 59 m and the overburden thickness overlays the aquifer unit extends from 3 to 20 m. The deeper aquifer zones were encountered between 30 and 59 m, which could be suitable for groundwater development, and the shallow aquifer occurs between 8 and 14 m, which is not encouraging for groundwater development and may be susceptible to surface contaminations. However, for water security and sustainability, multiple boreholes should be sited at the delineated aquifer promising zone where the aquifer is fractured and occurs within a depth of 30 m and above. The weathered/fractured units constitute the regional aquifer units, which are largely responsible for the groundwater potential. The hydraulic conductivity of the regional aquifer was estimated to vary between 0.337 and 10.62 m/day, which invariably enhances the aquifer recovery processing. Groundwater quality and the risk of surface contamination were examined through overburden protective index capacity.

Hydrochemical Characteristics and Water Quality of Shallow Groundwater in Desert Area of Kunyu City, Southern Margin of Tarim Basin, China

The Tarim Basin in Xinjiang is located in the northwest inland arid region of China, but research shows that the region is rich in groundwater resources. To understand the hydrochemical characteristics and water quality of shallow groundwater in the desert area of the southern margin of the Tarim Basin, the groundwater was systematically sampled and tested. The ion characteristics and evolution mechanism of groundwater were analyzed by mathematical statistics, Schukarev classification, Piper three-line diagram, Gibbs model and ion ratio. Water quality was evaluated by the water quality index method (WQI) and irrigation water suitability-related parameters. The results indicated that the dominant cation in the study area is Na+, and the main dominant anions are SO42− and Cl−. According to total dissolved solids (TDS), the groundwater mainly belongs to brackish water and semi-saline water. The hydrochemical chemistry types are mainly Cl·SO4-Na·Mg type, followed by Cl-Na type, and the ion source is mainly the weathering and dissolution of evaporation rock, silicate and sulphate. The hydrochemical process is primarily controlled by evaporation concentration and rock weathering, and the cation exchange is weak. Furthermore, the WQI spatial distribution map shows that the groundwater in the middle of the study area is unsuitable for drinking and there are two areas with high WQI values greater than 500. In contrast, the good-excellent groundwater is scattered in the East. The groundwater generally has high to very high salinity, with significant changes in alkalinity. In addition, 54% of the water samples exceed the magnesium hazard (MH) limit. Therefore, certain measures should be taken before irrigation. This study has important implications for the rational development and reasonable utilization of local groundwater.

Study on the Carrying Capacity and Change Trend of Groundwater Resources in Coal Mining Area: A Case Study of a Coal Mine in Northwest China

The groundwater resources carrying capacity is a comprehensive metric that assesses the ability of groundwater resources in a region to support industrial production and socioeconomic development. In arid regions, the calculation and analysis of the carrying capacity of groundwater resources are of paramount importance for guiding sustainable mining practices in coal mines. This study utilized a combination of the Fuzzy Comprehensive Evaluation (FCE) method and the Analytic Hierarchy Process (AHP) method to analyze the carrying capacity of groundwater resources in the coal mine located in northwest China. The results showed that the groundwater resources carrying capacity in the study coal mine was at a low level from 2011 to 2020 and the development and utilization of groundwater will reach its limit. The change trend of the carrying capacity showed a slight increase following a decline, with the highest value 0.5021 and the lowest 0.3518. The factors that significantly impacted the size of the carrying capacity included the total groundwater resources, the degree of groundwater development and utilization, and the per unit GDP of water consumption. To ensure sustainable development, the optimization of coal mining technology and the improvement of groundwater utilization efficiency should be promoted, while the rate of groundwater development should be slowed. The findings of this study offer valuable insights for guiding the sustainable development of groundwater resources in the coal mine of arid areas in the future and have practical implications.

Distribution, enrichment mechanisms, and health risk assessment of high-fluorine groundwater in the Yudong Plain, Henan Province, China.

The Yudong Plain is in the eastern part of Henan Province, China, where there is little rain and high evaporation. Compared to other areas in Henan Province, the groundwater fluorine content is generally high, which affects the health of residents. Based on the systematic analysis of water chemistry data of shallow and mid-depth groundwater samples in the Yudong Plain, the causes of shallow and mid-depth high-fluorine groundwater in the Yudong Plain were explored using mathematical statistics, spatial interpolation, and ion ratios. The results show that the fluorine contents of both shallow and mid-depth groundwater in the study area are high. The shallow samples had fluorine contents ranging from 0.1 to 4.89mg/L, with an exceedance rate of 48% and an average content of 1.15mg/L. The fluorine content of mid-depth samples ranged from 0.14 to 3.32mg/L, with an exceedance rate of 68% and an average content of 1.33mg/L. The shallow high-fluorine groundwater is mainly distributed in the central low-lying area, and its main hydrochemical type is HCO3-Na·Mg; the mid-depth high-fluorine groundwater is mainly distributed in strips in the north and east of the study area, and its main water chemistry type is HCO3-Na. Fluorine enrichment in shallow groundwater in the study area is controlled by rock weathering, evaporation concentration, and competitive adsorption, while leaching and dissolution of fluorine-containing minerals in sedimentary strata are the main factors influencing fluorine enrichment in mid-depth groundwater. The results of the human health risk assessment (HRA) showed that the mean non-carcinogenic hazard quotients (HQs) in shallow groundwater were 0.95, 0.64, 0.57, and 0.55 for infants, children, teenagers, and adults, respectively, while the mean non-carcinogenic HQs in mid-depth groundwater were 1.11, 0.74, 0.66, and 0.63, respectively. The study provides a scientific basis for the rational development and use of groundwater in the area and offers theoretical support for the prevention and control of groundwater pollution.

Hydrochemistry and groundwater quality assessment around solid waste landfill sites in peri-urban Jaipur, NW India.

Jaipur, the capital city of Rajasthan State in northwestern India, is one of the fastest-growing urban centers in the country. The city and the region around it have documented a substantial drop in the water table due to the over-abstraction of groundwater resources to cater to the increasing water demands of the growing population. Consequently, the entire Jaipurdistrict has been categorized as a "dark zone," prohibiting any further groundwater development activity. Besides its dwindling availability, water quality is also a matter of concern. In places, the water is geogenically contaminated and unsuitable for drinking purposes due to high levels of undesired elements in groundwater, such as high fluoride in the southern part and high chloride in the southwestern part of the district. Groundwater contamination can also occur through several anthropogenic factors, such as industrialization and excessive use of insecticides and pesticides. Water pollution through sewage disposal in open land-fill sites is also an important factor, especially in the growing urban centers. In this study, the water quality evaluation around three landfill sites in the Jaipur district, namely Mathura Das Pura and Langadiyawas (east of the city) and Sewapura (northwest of the city), was carried out. The cation-anion analysis of 45 groundwater samples collected around these sites reveals a wide variation in the abundance of constituent parameters. In a majority of cases, most of the parameters are within acceptable limits prescribed by the national and international agencies (Bureau of Indian Standards and World Health Organization). The fluoride content is more than the prescribed limit of 1.5mg/l in several cases. This could be an intrinsic property of deeper aquifers. The majority of Mathura Das Pura and Langadiyawas samples classify as Na + K - CO3 + HCO3 to Mg - CO3 + HCO3 types in the Piper classification scheme, while a small proportion shows mixed water type characteristics, i.e., with no dominant parameter. Most of the samples have heavy metal abundances within the permissible limits while slightly elevated Cd and Pb levels were observed in some samples. A positive correlation between these two metals can be attributed to a common pollutant, possibly sourced from solid waste. The percent pollution index of Sewapura samples shows lower pollution levels (PPI < 40%) and a dominant chemical weathering trend while the majority of Mathura Das Pura-Langdiyawas samples show a high pollution effect (PPI 40 to 80%). In general, the chemical parameters of Sewapura (relatively new landfill site) samples define a more coherent group while water quality parameters in Mathura Das Pura and Langdiyawas (old landfill sites) samples show a wide variation, unsystematic distribution, and significantly higher than prescribed values for most of the hydrochemical parameters. The study shows that some of the water quality issues may be geogenic, while municipal waste dumping and leachate infiltration have adversely affected the groundwater quality.

Integration of hydrogeological data, GIS and AHP techniques applied to delineate groundwater potential zones in sandstone, limestone and shales rocks of the Damoh district, (MP) central India

The Damoh district, which is located in the central India and characterized by limestone, shales, and sandstone compact rock. The district has been facing groundwater development challenges and problems for several decades. To facilitate groundwater management, it is crucial to monitoring and planning based on geology, slope, relief, land use, geomorphology, and the types of the basaltic aquifer in the drought-groundwater deficit area. Moreover, the majority of farmers in the area are heavily dependent on groundwater for their crops. Therefore, delineation of groundwater potential zones (GPZ) is essential, which is defined based on various thematic layers, including geology, geomorphology, slope, aspect, drainage density, lineament density, topographic wetness index (TWI), topographic ruggedness index (TRI), and land use/land cover (LULC). The processing and analysis of this information were carried out using Geographic Information System (GIS) and Analytic Hierarchy Process (AHP) methods. The validity of the results was trained and tested using Receiver Operating Characteristic (ROC) curves, which showed training and testing accuracies of 0.713 and 0.701, respectively. The GPZ map was classified into five classes such as very high, high, moderate, low, and very low. The study revealed that approximately 45% of the area falls under the moderate GPZ, while only 30% of the region is classified as having a high GPZ. The area receives high rainfall but has very high surface runoff due to no proper developed soil and lack of water conservation structures. Every summer season show a declined groundwater level. In this context, results of study area are useful to maintain the groundwater under climate change and summer season.The GPZ map plays an important role in implementing artificial recharge structures (ARS), such as percolation ponds, tube wells, bore wells, cement nala bunds (CNBs), continuous contour trenching (CCTs), and others for development of ground level. This study is significant for developing sustainable groundwater management policies in semi-arid regions, that are experiencing climate change. Proper groundwater potential mapping and watershed development policies can help mitigate the effects of drought, climate change, and water scarcity, while preserving the ecosystem in the Limestone, Shales, and Sandstone compact rock region. The results of this study are essential for farmers, regional planners, policy-makers, climate change experts, and local governments, enabling them to understand the groundwater development possibilities in the study area.

Sub-Watershed Prioritization of Kariangote River in Kerala Based on Drainage Morphometry and Geomorphology – A Remote Sensing and GIS Approach

Objectives: This article examines the geohydrological behaviour of the Kariangote watershed and prioritizes its subwatersheds based on groundwater presence. Methods: Remote sensing and GIS techniques were used to study the morphometric and geomorphologic characteristic of the watershed. Six sub-watersheds were identified, and various morphometric and geomorphic parameters were calculated. Based on the relative importance to groundwater occurrence, sub-watersheds were prioritized by giving suitable weightage to morphometric and geomorphological units. Findings: Sub-watershed IV is the most deficit one and is given priority followed by III the next, V, II, I, and VI. Sub-watershed VI is with surplus groundwater and is given the last priority. Novelty: Higher priority should be given to conservation practices in sub-watersheds to prevent surface runoff and soil erosion and to increase groundwater levels. Sub-watersheds with highly permeable subsurface formation could be suggested for rainwater harvesting and artificial recharge of groundwater. Planning further groundwater development projects and managing watersheds would be aided by this study. Keywords: Morphometry; Coastal Alluvium; Flood Plain; Groundwater; Prioritization

Paleo‐Hydrogeological Modeling to Understand Present‐Day Groundwater Salinities in a Low‐Lying Coastal Groundwater System (Northwestern Germany)

AbstractGroundwater abstraction and drainage are considered to be the main drivers for the salinization of low‐lying coastal groundwater systems, while the role of past boundary conditions is less clear. In this study, 3‐D paleo‐hydrogeological variable‐density groundwater flow and salt transport modeling (“paleo‐modeling”) is applied to reconstruct the evolution of groundwater salinities during the Holocene, that is, the last 9,000 years, in Northwestern Germany. Novel aspects of this study include the consideration of highly resolved time‐variant boundary conditions in a 3‐D paleo‐modeling framework, for example, sea‐level rise, surface elevation and coastline changes, development of drainage networks and groundwater abstraction, as well as the quantification of isolated processes impacting salinization. Results show that salinization was a function of sea‐level rise from 9000 BP until 1300 CE. The creation of the dike line ∼1300 CE set the starting point for increasing anthropogenic control of the hydro(geo)logical system: changes in surface elevation and drainage of low‐lying marshes have become main drivers for salinization after 1600 CE when peat was artificially degenerated. Moreover, changes in the dike line caused by storm floods impacted the salinities. Model results for 2020 CE match well with present‐day salinity observations. Yet, salinization will continue in the future, as the hydro(geo)logical system has not reached an equilibrium. The presented paleo‐modeling framework can be viewed as a blueprint for similar low‐lying coastal groundwater systems, influenced by marine transgression and human development. Thereby, it enables the reconstruction of meaningful present‐day salinity distributions, serving as a vital basis for modeling future groundwater systems in a changing climate.

Assessment of the Nubian aquifer characteristics by combining geoelectrical and pumping test methods in the Omdurman area, Sudan

The recent research is carried out to model the characteristics and productivity of the groundwater aquifer in the Omdurman area, Sudan, by combining electrical resistivity and pumping test methods. Omdurman is the most populous city known as the traditional capital of Sudan. Vertical electrical sounding (VES) survey using Schlumberger array is carried out along four profiles to delineate the potential groundwater zones. Application of 1D geophysical inversion revealed five geoelectric layers, including recent deposits, clay, silicified and ferruginous sandstone, and sandstone. Additionally, based on the outcome of VES inversion, Dar Zarrouk parameters, including transverse resistance and longitudinal conductance, were calculated to model the aquifer characteristics. The transverse resistance ranged from 5587 to 309,853 Ωm2, while the longitudinal conductance varied between 0.14 and 2.5 Ω−1. The hydraulic conductivity and transmissivity are further measured using the VES data, ranging from 1.4 to 5.2 m/d and 435 to 1564 m2/day, respectively. The step-drawdown pumping tests were performed to evaluate the aquifer characteristics and thus validate the result of the geoelectrical method. The transmissivity obtained from the step test varied between 583 and 1226 m2/day, showing an acceptable agreement with those of geoelectrical data. Based on the measured parameters, the aquifer is classified as highly productive and ideal for groundwater development. The step drawdown test was further used to assess the performance of groundwater wells. The results indicated that faulty well design and inappropriate pumping rates influence some wells in the study area, resulting in high drawdown and low well efficiency. Overall, the objectives of the study were successfully achieved; nonetheless, detailed hydrogeological and geophysical investigations are recommended for comprehensive evaluation of the groundwater aquifer.

Evidence for Groundwater Salinity Origin Based on Hydrogeochemical and Isotopic (2H, 18O, 37Cl, 3H, 13C, 14C) Approaches: Sousse, Eastern Tunisia

The key processes responsible for the rise in groundwater salinization in the Mio–Pliocene aquifer system of Sousse (Tunisia, eastern coastline) were identified through a multidisciplinary approach based on the use of geochemical, stable (2H, 13C, 18O and 37Cl) and radioactive (3H and 14C) isotope methods. In the study region, the mineralization of groundwaters is related to water–rock interaction ascribed to the dissolution of minerals in evaporite rocks, as well as to saltwater intrusion. Both processes explain the development of groundwaters in which Cl and Na dominantly determine the groundwater quality deterioration state. The isotopic and geochemical signatures of the studied groundwaters are clearly explained by the (i) occurrence of saline basins (sebkhas adjacent to the study region), (ii) type of rocks found below the ground surface, and (iii) cation exchange between clays and groundwaters.