Recharge Zone Research Articles

Delineating groundwater recharge zones: semi-arid NW Algeria case study

In arid and semi-arid regions, groundwater is a vital resource increasingly impacted by population growth and agricultural demands. This study identifies potential groundwater recharge zones in the Oued Isser-Sikkak Basin, northwestern Algeria, using the Analytic Hierarchy Process (AHP) integrated with Geographic Information Systems (GIS). Six thematic layers—land use, slope, geology, drainage density, lineament density, and rainfall—were weighted and combined to produce a recharge potential map. The basin was classified into five categories: very high (4%), high (33.7%), moderate (45.6%), low (12.5%), and very low (1.9%) recharge potential. The highest potential zones were found in the south and east, where limestone and dolomite formations prevail. Validation with field observations and previous research showed an 83.7% match, confirming the model’s reliability. The study demonstrates the effectiveness of integrating AHP and GIS in assessing groundwater potential, offering a valuable tool for sustainable water resource management in data-limited, dryland areas.

Mapping groundwater potential and recharge for advisory and monitoring systems in Zimbabwe’s Upper Manyame sub-catchment

This study investigated geospatial technologies to model groundwater potential (GWP) in the Upper Manyame sub-catchment (UMSC) and assess the impact of changing land use/land cover on groundwater recharge zones. Landsat images spanning 1980 to 2020 were processed using a maximum likelihood classifier algorithm in a GIS environment. Future land use for 2030 was predicted using Markov Chain analysis. Utilizing geology, soil, lithology, lineament density, slope, total wetness index, and drainage density data, groundwater recharge and potential were mapped. Weights were assigned, and a spatial modelling system using Fuzzy Logic created weighted maps. The study revealed significant land cover changes. GWP mapping results exhibited a strong correlation with borehole yield data, validating the efficacy of fuzzy logic as a grading technique. The web GIS interfaces, offering diverse features, provide groundwater managers with tools to visualize groundwater potential zones and access borehole data online, facilitating informed decision-making for sustainable resource management.

GIS-based multi-criteria decision-making for identifying potential artificial groundwater recharge zones in the Tikurwuha watershed of Ethiopia

GIS-based multi-criteria decision-making for identifying potential artificial groundwater recharge zones in the Tikurwuha watershed of Ethiopia

Exploring a long distance, amagmatic, across-suture orogenic geothermal system: Sri Lanka's foreland hot springs.

Hot springs in orogenic geothermal systems are usually within 5-15km of the recharge zone, either within the mountain range or along the mountain front. However, in Sri Lanka, hot springs are in the foreland up to 100km away from their recharge zones in the Highland Complex. The absence of a sedimentary cover provides the opportunity to study fluid pathways along basement faults and fractures. We identify a fracture network that connects the recharge and discharge zones oriented 015°-090°. Its orientation to the regional stress field indicates that the majority of the faults and fractures are permeable to allow fluid transport. With a geothermal gradient of ∼20°C/km obtained from 1D modeling, the estimated maximum circulation depth of the hot spring water is 3.5-5km. Such foreland geothermal systems may also occur in other parts of the world hidden under a sedimentary cover, which could provide an immense geothermal resource.

Groundwater recharge zone mapping in a coastal mediterranean aquifer applying fuzzy and analytical hierarchy process and frequency ratio: A case study of northeast Tunisia

Groundwater recharge zone mapping in a coastal mediterranean aquifer applying fuzzy and analytical hierarchy process and frequency ratio: A case study of northeast Tunisia

Comprehensive evaluation of groundwater quality and drought susceptibility in Jazmurian Basin Iran using integrated statistical GIS analysis.

Arid regions face a dual threat of declining groundwater quantity and quality. This study examines these interconnected challenges in the diverse aquifers of Iran's Jazmurian Basin using GIS and statistics. The study reveals significant spatial variations in salinity, hardness, and sodium content. Of particular concern is the rising electrical conductivity (EC) across most aquifers, especially in the east, which indicates potential water quality degradation. The relationship between groundwater level and salinity is intricate and requires site-specific management. Cluster analysis has identified three distinct groundwater profiles: deep formations that require geological understanding for salinity control, high-quality zones that need recharge protection, and areas that struggle with salinity sources that require identification. Factor analysis identifies salinity and aridity, mineral content related to rock weathering and agriculture, recharge zones requiring protection, and complex interactions between specific ions and groundwater level as key drivers. This study highlights the importance of implementing comprehensive management strategies considering spatial variations, temporal trends, and unique drivers. Targeted interventions, sustainable water use, and effective monitoring programs are essential for safeguarding this vital resource in drought-prone regions. Further research is necessary to refine our understanding of human influences and unique geochemical processes shaping each aquifer system, ultimately enhancing global arid zone groundwater management.

Factors causing groundwater acidification in the high land area of Ho Chi Minh City, Vietnam.

This study explores the causes of the acidic nature of the metal-rich, dilute groundwaters in the highland area of Ho Chi Minh City (HCMC), which is populated and mostly used for domestic, agricultural, and industrial purposes. The groundwater is generally very dilute (176 ± 128µS/cm in electrical conductivity, 70 ± 220 µeq/L in alkalinity), but high in redox potential (343 ± 55mV), and nitrate concentrations (19 ± 19mg/L). Since the area corresponds to the highland and, thus, serves as a groundwater recharge zone. However, 53% and 90% of the investigated groundwater samples (n = 58) showed pH lower than 4 and 5, respectively, and, thus, 43%, 21%, and 7% of groundwater samples showed Al, Pb, and Cr concentrations exceeding their respective drinking water standards recommended by World Health Organization. Although nitrification is the most common acidification driver in the agricultural and/or urbanized lands, the nitrate concentration in this study area is strangely low compared to similar acidic groundwaters reported from other agricultural regions. To find out the causes of acidification, this study investigated the geochemical processes from the extensive groundwater chemistry data and performed geochemical simulations by changing water alkalinity and cation exchange capacity (CEC) of sediment and matching the results with the observed water chemistry data to confirm our hypothesis. Based on this approach, we could reveal that groundwaters of this study could become very acidic due to its dilute nature and low sediment CEC. Since groundwaters are generally very dilute in the recharge area, our finding provides another reason for the discreet management of highland areas where groundwater recharge is concentrated.

Potentiality Delineation of Groundwater Recharge in Arid Regions Using Multi-Criteria Analysis

This study integrates morphometric analysis, remote sensing, and GIS with the analytical hierarchical process (AHP) to identify high potential groundwater recharge areas in Wadi Abadi, Egyptian Eastern Desert, supporting sustainable water resource management. Groundwater recharge primarily comes from rainfall and Nile River water, particularly for Quaternary aquifers. The analysis focused on the Quaternary and Nubian Sandstone aquifers, evaluating 16 influencing parameters, including elevation, slope, rainfall, lithology, soil type, and land use/land cover (LULC). The drainage network was derived from a 30 m-resolution Digital Elevation Model (DEM). ArcGIS 10.8 was used to classify the basin into 13 sub-basins, with layers reclassified and weighted using a raster calculator. The groundwater potential map revealed that 24.95% and 29.87% of the area fall into very low and moderate potential categories, respectively, while low, high, and very high potential zones account for 18.62%, 17.65%, and 8.91%. Data from 41 observation wells were used to verify the potential groundwater resources. In this study, the ROC curve was applied to assess the accuracy of the GWPZ models generated through different methods. The validation results indicated that approximately 87% of the wells corresponded accurately with the designated zones on the GWPZ map, confirming its reliability. Over-pumping in the southwest has significantly lowered water levels in the Quaternary aquifer. This study provides a systematic approach for identifying groundwater recharge zones, offering insights that can support resource allocation, well placement, and aquifer sustainability in arid regions. This study also underscores the importance of recharge assessment for shallow aquifers, even in hyper-arid environments.

Hydrochemical facies distribution, controlling mechanisms and natural background concentrations of major pollutants in Ganga-Yamuna interfluve aquifer, India.

Hydrochemical facies distribution, controlling mechanisms and natural background concentrations of major pollutants in Ganga-Yamuna interfluve aquifer, India.

Spatial–Temporal Differentiation of Ecosystem Service Trade-Offs and Synergies in the Taihang Mountains, China

Mountains are crucial for essential ecosystem services that are foundational to ecological restoration and conservation. The Taihang Mountains are a key water recharge zone and ecological barrier in northern China. Yet, research on the spatial heterogeneity of ecosystem service trade-offs and synergies in this region remains scarce. This study addresses this gap by examining the spatiotemporal evolution, spatial heterogeneity, and the dynamic interplay between ecosystem service trade-offs and synergies in the Taihang Mountains, employing the multidimensional analysis method of time and space. Key findings from 2005 to 2020 show a significant CNY 2.665 billion increase in overall ecosystem service value in the Taihang Mountains. Spatially, soil conservation increased in the central and eastern regions, while water supply similarly increased in the northern region. Regarding spatial autocorrelation, the spatial distribution of these services was predominantly characterized by clusters of high–high and non-significant values. Regarding the spatiotemporal differentiation of trade-offs and synergies in ecosystem services, synergies prevail, with significant spatial disparities between trade-off and synergistic areas, where trade-offs are relatively scattered. Comprehending the interactions, trade-offs, and synergies among ecosystem services is crucial for natural resource allocation in the Taihang Mountains. This understanding facilitates resolving conflicts between economic and environmental goals, promoting harmonious regional development.

Hydrochemical characteristics, water quality, and probabilistic health risk assessments of groundwater in Caraveli Province, South Peru

ABSTRACT Despite its scarcity, groundwater in Marcona’s catchment area represents the primary source of water for the local population of Caraveli Province, Peru. In this study, hydrochemical analyses, Entropy Water Quality Index (EWQI) evaluations, and health risk assessments (HRAs) were conducted to determine the quality and probabilistic health risks of groundwater. The results indicated that the hydrochemistry of groundwater was primarily influenced by evaporation, water–rock interactions, and anthropogenic activities. The recharge zone was a relatively suitable source for irrigation. Groundwater within the catchment zone failed to meet certain irrigation standards, and groundwater from the remaining zones was not suitable for irrigation. EWQI values indicated that approximately 41.9% of the samples were suitable for drinking. Notably, the sensitivities of Fe, Cl−, Na+, NO3 −, and SO4 2− were 13.18%, 2.02%, 1.71%, 1.28%, and 1.23%, respectively. Probabilistic noncarcinogenic HRAs determined the health risks associated with NO3 −, Fe, and Mn to be 9.3% for adults and 31.9% for children. These noncarcinogenic health risks were primarily attributable to Fe and NO3 −. In summary, this study explores the mechanism underlying water quality and health risks in arid regions, underscoring the importance of enhancing public awareness regarding the long-term consequences of consuming contaminated groundwater.

Hydrothermal Characterization of the Jazan Geothermal System, Saudi Arabia

Abstract Al Ardah region in Southwestern Saudi Arabia is known for its hot springs, indicating an active geothermal system. However, there is no established conceptual model to explain how this system works. Therefore, the main objective of this study is to understand the hydrothermal characteristics of the area and develop a conceptual model by integrating hydrochemical analyses with geological information. To achieve this, water samples were collected from the hot springs and analyzed in the laboratory using geochemical techniques. This analysis allowed us to characterize hydrothermal system and estimate the geothermal reservoir temperature. In addition, outcrop observations were collected near the hot springs and possible recharge areas to investigate fractures and potential pathways for fluid flow based on the orientation of open fractures (joints). Our findings indicate that the thermal waters are characterized by Na-Cl water, suggesting that the water is discharged from a significant depth of the reservoir. The estimated reservoir temperature ranges from 140°C to 180°C. The high levels of Li and Sr imply a strong interaction between the thermal water and the granitic rock. Furthermore, precipitation is found to be the primary source of recharge for this system. Based on our analysis of various elements, we believe the thermal water flows from the east to the west through joints and faults, indicating the recharge zone is in the eastern part of the hot spring area. This study greatly enhances the understanding of the Al Ardah geothermal system in Jazan by integrating hydrochemical analysis and structural geology observations.

An integrated application of remote sensing, geographic information system, and analytical hierarchy process for identification of potential groundwater recharge zones across Potohar Plateau, Pakistan

ABSTRACT Groundwater depletion is a common issue in the Potohar Plateau region of Pakistan. The identification of potential recharge zones in this region can help to overcome the issue. This research aims to develop a map of the most suitable groundwater recharge (GWR) zones by integrating remote sensing and geographic information systems to categorize and demarcate GWR potential locations in the Potohar Plateau. The analytic hierarchy process (AHP) is used to combine drainage density, curve number (CN), land use and land cover, evapotranspiration, slope, geology, and rainfall. The method utilized in this research constitutes the demarcation and assigning weights to parameters, and the development of a GWR suitability map. Four zones have been identified for the study area. This investigation showed that excellent and good sites accounted for around 41.9% of the overall area. Sensitivity analysis reveals that drainage density, rainfall, CN, and slope are the most influencing parameters. The results demonstrated that moderate and unsuitable sites covered about 58.1% of the total area. The GWR suitability map offers essential information to water resource engineers, planners, and decisionmakers to manage the water resources.

Delineating Ababi Mountains spring recharge zones using combined isotope hydrology and geophysical methods

Sustainable groundwater management requires accurate identification of spring recharge zones, particularly in volcanic regions where water resources are critical. This study aimed to delineate the groundwater recharge zone of the Ababi Spring in Bali’s Karangasem Regency by integrating isotope hydrological and geophysical techniques. Water samples were collected from five locations (211–978 m a.s.l.) and analysed for stable isotopes (δ2H or δD and δ18O). Vertical electrical sounding and audio magnetotelluric surveys were conducted to validate findings and map subsurface structures. The local meteoric water line was established (δ2H = 4.4912δ18O + 7.1419) and an isotope-elevation relationship was developed. The spring water exhibited depleted isotopic values (δ18O: −7.706‰, δ2H: −39.748‰) compared to local precipitation, indicating a higher-altitude source. The analysis identified the recharge zone at approximately 2,118 m a.s.l. Geophysical surveys revealed subsurface structures connecting the recharge area to the spring, with resistivity patterns indicating preferential flow paths going through fractured volcanic rocks. The effectiveness of this integrated approach was further validated through additional isotopic analysis of rainfall at 1,514 m a.s.l. This supported the established isotope-elevation relationship model (R2 = 0.6847). The study demonstrates the value of combining hydrochemical and geophysical methods for accurate recharge zone delineation in a volcanic terrain, particularly in regions with complex hydrogeological settings. These findings provide crucial information for implementing targeted conservation strategies and ensuring sustainable water resource management in the Karangasem region, while establishing a methodological framework applicable to similar volcanic environments.

Mapping Groundwater-Potential Zones Using Geospatial and Decision-Making Approaches: Case Study of Ghiss-Nekkour Watershed in Northeastern Morocco

Accelerated population growth has led to a heightened demand for water resources, resulting in a notable decline in underground water storage – especially in coastal areas. To effectively manage this crucial resource, the objective of this research work is to identify potential groundwater recharge areas in the Ghiss-Nekkour watershed using Saaty’s multi-criteria analysis combined with GIS and remote-sensing techniques. Initially, this work involved gathering spatial information that was related to the various parameters that govern recharge and express it in thematic maps: slope, altitude, geology, rainfall, soil, land cover, and drainage density. A reclassification was made according to their degrees of involvement in the recharge process by Saaty’s analytical hierarchy process (AHP); this was followed by a weighting of these parameters. These were subsequently integrated into a GIS in order to establish a map of potential groundwater recharge zones in the Ghiss-Nekkour watershed. The groundwater-potential map resulted in five classes:– good (165 km2) and excellent (0.9 km2) aquifer recharge potentials – situated in north and southwest portions of study area;– moderate (617 km2) aquifer recharge potentials – located in western and southern parts of watershed;– fair (551 km2) and poor (44 km2) aquifer recharge potentials – located in central zone and southeastern part of Ghiss-Nekkour watershed.Field surveys that were conducted in November 2022 and October 2023 validated the obtained results.

Delineating Potential Groundwater Recharge Zones in the Semi‐Arid Eastern Plains of Rajasthan, India

ABSTRACTSurface and subsurface anomalies, hydrological conditions, and dynamic interactions between embedded thematic layers influence groundwater recharge potential (GRP). Conducting a GRP study plays an essential role in promoting the sustainable use of groundwater resources amid a growing population and unplanned urbanization. This study focuses on assessing GRP in the semi‐arid eastern plains of Rajasthan by delineating groundwater potential zones (GPZs) using an integrated approach involving remote sensing and geographical information system (RS‐GIS) technique and analytical hierarchy process (AHP) method. Research findings indicate that the region dominated by fine sand, silt and clay, pediment‐pediplain complex, aeolian sand sheet, higher drainage density, cambisols soil, river channels, floodplains, water bodies, soil hydraulic conductivity and higher surface wetness significantly contributed to good recharge potential in plains of the region. Additionally, lineaments, hills and valleys regulate water movement. A strong negative correlation (–0.78) between decadal‐mean‐depth fluctuation and GPZs frequency classes validates identifying high potential zones in areas with low mean‐depth fluctuation. Sensitivity analysis highlights geology and geomorphology as crucial factors. However, the study addresses potential limitations and challenges, such as data scaling and spatial resolution issues due to nonlinear pixel fusion algorithms and AHP method‐related limitations in model interpretation. The current study presents a convenient approach for improving groundwater resource management in hydrogeologically sensitive and drought‐prone regions.

Analysis and Mapping of the Distribution of Groundwater Recharge Areas Using the Scoring Method (Case Study: Singgahan and Montong District, Tuban).

Abstract Tuban Regency, located in the northern part of East Java, borders the Java Sea to the north and is intersected by several rivers. The presence of numerous rivers and limestone or karst hills in regions like Singgahan and Montong Districts suggests significant potential for these areas to function as groundwater recharge zones. A groundwater recharge area is characterized by the vertical movement of groundwater, driven by the flow of water along the gradient of aquifers. Identifying and preserving these recharge zones in Singgahan and Montong is crucial to maintaining the groundwater supply, ensuring its availability in sufficient quantity and quality to meet the ongoing needs of ecosystems and human consumption. This study utilizes a scoring method to identify potential recharge areas, incorporating parameters such as land cover, soil type, rainfall, and slope inclination. In this method, each parameter is assigned a specific weight: slope inclination (20%), soil type (35%), rainfall (15%), and land cover (30%). The analysis revealed that the land cover in these districts primarily consists of plantations, with 6,840.63 hectares in August and 6,761.88 hectares in October. The slope inclination in Singgahan District is predominantly flat, covering 8,417.68 hectares. Both Singgahan and Montong Districts experience low rainfall, with 57% of the total area, equivalent to 12,670.89 hectares, falling into this category. The most prevalent soil type is Cambisol, which constitutes 33% of the area, or 7,463.46 hectares. Using the scoring method, it was determined that in August, Singgahan and Montong Districts possess high potential for recharge areas, with high-level recharge zones covering 1,314.70 hectares and medium-level recharge zones spanning 18,498.78 hectares. By October, the extent of high-level recharge zones had increased to 3,499.20 hectares, while medium-level recharge zones covered 16,942.45 hectares. These findings underscore the importance of managing these recharge areas to sustain groundwater resources effectively.

Karst groundwater conservation based on hydrochemistry and isotope stable analysis in Obi Island, South Halmahera

Abstract This paper presents an analysis of the hydrogeological characteristics of the Kelo karst area in Obi Island, South Halmahera, focusing on hydrochemistry and isotopic methods to delineate the groundwater recharge zones and propose conservation measures. Despite its natural state, the Kelo karst area has not been previously studied for hydrogeology nor exploited for resources. Unregulated exploitation of karst areas poses significant environmental risks, leading to the degradation of their strategic and hydrological functions. This study investigates spring characteristics through hydrochemistry analysis, stable isotopes (δ18O and δ2H), and groundwater mixing processes. Hydrochemistry and isotopic analyses elucidate the hydrogeological features, including groundwater origin and recharge mechanisms. The predominant groundwater facies in the study area exhibit a Ca-Mg-HCO3 − composition, reflecting the dissolution processes of both limestone and igneous rock formations. Isotopic analysis and local meteoric water line examination indicate a recharge zone elevation ranging from 612 to 945 meters. Geological features such as fracture zones, lineaments, faults, and sinkholes significantly influence the determination of recharge areas. Protection of these recharge zones is imperative for groundwater conservation, ensuring the sustained availability and quality of groundwater amidst the development pressures on karst landscapes.

Groundwater exploration using self potential and resistivity geoelectrical method as drought disaster mitigation at bukit intan sub-district, Pangkalpinang

Abstract Pangkalpinang City in Bangka Belitung Islands province faces a seasonal water crisis due to its location outside the island’s groundwater basin. This study focuses on assessing groundwater potential in the Bukit Intan sub-district to support drought mitigation efforts. Using a combination of self-potential (SP) and geoelectrical resistivity methods, groundwater flow and aquifer depth were analyzed. Field data were collected across multiple tracks, with SP measurements revealing areas of potential groundwater movement, while resistivity profiles indicated aquifer presence at depths of 3-30 meters. Results suggest that groundwater potential is concentrated in certain recharge zones, highlighting areas suitable for targeted extraction and the establishment of boreholes. These aquifers exhibit seasonal fluctuations in groundwater levels, whereas the confined zones are located at greater depths and are more isolated, likely due to the presence of resistive layers that restrict flow. This assessment provides crucial insights for improving groundwater management in drought-affected regions of Pangkalpinang City.

Comparative Analysis of Multi‐Criteria Decision‐Making Approaches for Identifying Groundwater Recharge Potential Zones in the River Basin of Northern Kerala, India

ABSTRACTGroundwater resources are increasingly strained by misuse and climate change, necessitating the identification of potential recharge zones for sustainable management. The study aimed to simulate potential recharge zones of a tropical river basin using two multi‐criteria decision‐making techniques: the Analytical Hierarchy Process (AHP) and Multi‐Influencing Factor (MIF) methods. Thematic layers of key variables were integrated using a weighted overlay analysis in GIS environment to model recharge areas within a tropical river basin in Northern Kerala, India. Normalized weights and ranks were calculated to evaluate their influence on groundwater development. Five classes of groundwater recharge potential zones (GWRPZ) with their derived areas were identified for AHP and MIF, respectively: high (30.39% and 28.24%), low (21.55% and 21.60%), very high (19.20% and 18.45%), moderate (16.96% and 20.25%), and very low (11.90% and 11.45%). Validation with overall accuracy and Kappa coefficient confirmed the methods' comparability. The results guide water well site selection and improve managed aquifer recharge (MAR) strategies. Local bodies within the river basin were ranked utilizing the Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) method to prioritize and implement recharge schemes, aiding sustainability goals in groundwater management.