Groundwater Recharge Potential Zones Research Articles

Groundwater potential and recharge zone mapping using GIS and remote sensing techniques: the Melka Kunture Watershed in Ethiopia

Groundwater is the most dynamic natural resource that is not uniformly distributed both in space and time. Identifying it for sustainable water resource development for domestic use, irrigation, and industrial purposes is the biggest challenge and key concern due to climate change, overexploitation, and a lack of proper management. Geographical information system (GIS) and remote sensing (RS) play a fundamental role in identifying suitable groundwater potential and recharge zones. In this study, groundwater potential and recharge zone map are delineated using GIS and RS techniques integrated with Analytic Hierarchy Process (AHP) for the Melka Kunture Watershed in Ethiopia. The thematic layers used were: Lithology, geomorphology, slope, lineament density, land use/cover, rainfall, drainage density and soil. GIS has been used to integrate and overlay thematic layers using a weighted overlay analysis tool, whereas the AHP method has been used to assign the weights, normalize, and rank thematic layers and their associated sub-themes based on their suitability, characteristics, or influence on groundwater potential and recharge zones. The output groundwater potential zone map is categorized into four suitable zones: high potential cover 1105.60 km2 (25.70%), moderate potential 2308.00 km2 (53.73%), low potential 880.0 km2 (20.49%), and very low potential 47.80 km2 (1.10%), whereas there are three suitable groundwater recharge potential zones: high potential cover 250.20 km2 (5.80%), moderate recharge 3647.90 km2 (84.00%), and low recharge 443.50 km2 (10.20%) of the study area. Hence, the study areas have been more suitable for groundwater potential and recharge zones as compared to the total area. The groundwater potential map was validated using the existing water source and well points, and it indicated a good prediction accuracy of 88%. Thus, the delineated groundwater potential and recharge zone maps are reliable, and the resultant potentiality mapping has played a vital role in the sustainable development and management of the water resources in the study area.

Integrated Geospatial and Analytical Hierarchy Process Approach for Assessing Sustainable Management of Groundwater Recharge Potential in Barind Tract

Groundwater depletion in Bangladesh’s Barind tract poses significant challenges for sustainable water management. This study aims to delineate groundwater recharge potential zones in this region using an integrated geospatial and Analytical Hierarchy Process (AHP) approach. The methodology combines remote-sensing data with GIS analysis, considering seven factors influencing groundwater recharge: rainfall, soil type, geology, slope, lineament density, land use/land cover, and drainage density. The AHP method was employed to assess the variability of groundwater recharge potential within the 7586 km2 study area. Thematic maps of relevant factors were processed using ArcGIS software. Results indicate that 9.23% (700.22 km2), 47.68% (3617.13 km2), 37.12% (2816.13 km2), and 5.97% (452.70 km2) of the study area exhibit poor, moderate, good, and very good recharge potential, respectively. The annual recharge volume is estimated at 2554 × 106 m3/year, constituting 22.7% of the total precipitation volume (11,227 × 106 m3/year). Analysis of individual factors revealed that geology has the highest influence (33.57%) on recharge potential, followed by land use/land cover (17.74%), soil type (17.25%), and rainfall (12.25%). The consistency ratio of the pairwise comparison matrix was 0.0904, indicating acceptable reliability of the AHP results. The spatial distribution of recharge zones shows a concentration of poor recharge potential in areas with low rainfall (1200–1400 mm/year) and high slope (6–40%). Conversely, very good recharge potential is associated with high rainfall zones (1800–2200 mm/year) and areas with favorable geology (sedimentary deposits). This study provides a quantitative framework for assessing groundwater recharge potential in the Barind tract. The resulting maps and data offer valuable insights for policymakers and water resource managers to develop targeted groundwater management strategies. These findings have significant implications for sustainable water resource management in the region, particularly in addressing challenges related to agricultural water demand and climate change adaptation.

Determining Potential Groundwater Recharge Zones in the North Gujarat Region of Gujarat State Using Techniques of Geoinformatics and Multi-Criteria Decision Analysis

The rapid increase in population and industrialization has significantly raised the consumption of groundwater resources for domestic, agricultural, and industrial purposes. This study aims to develop groundwater recharge potential zone maps to assist in the construction of artificial recharge structures in the North Gujarat Region of Gujarat, India. An integrated approach of remote sensing (RS), geographical information system (GIS), and multi-criteria decision analysis (MCDA) were used to achieve this goal. Influencing factors of groundwater availability included geology, soil, lineament density, slope, rainfall, land use/land cover, geomorphology, and drainage density, were analyzed to delineate potential groundwater recharge zones. each influencing parameter was determined by using Saaty's Analytic Hierarchy Process (AHP) method, and sub-parameters were ranked according to the AHP scale. A weighted overlay analysis tool in ArcGIS software was employed to map the groundwater recharge potential zones in the North Gujarat region. The classified results of the recharge potential area in the study area consist of excellent (9.93%), good (27.90%), moderate (17.58%), poor (3.92%), and very poor (0.92%) These findings provide valuable insights for effectively planning and managing groundwater resource development in the region.

Identification of groundwater recharge potential zone using geospatial approaches and multi criteria decision models in Udham Singh Nagar district, Uttarakhand, India

Groundwater is a valuable natural resource, which is extensively used in agricultural, industrial as well as daily activities of human beings. It is an essential source of freshwater need of half of the world’s population. In this study Remote Sensing (RS) and Geographic Information Systems (GIS), along with Multi criteria decision models were used. The Analytical Hierarchy Process (AHP) was used to determine the weights of various themes and their classes in the study to identify the groundwater recharge zones in Udham Singh Nagar district. Nine thematic maps/layers were created using GIS methods and employed for the demarcation of groundwater potential zone (GWPZ). It was concluded that around 82% of the area is very suitable (very good and good) for ground water recharge, which suggests that there is a significant amount of potential for artificial recharge systems to be implemented. This can help to augment the natural recharge process, improve water quality, and reduce the strain on existing water sources. Whereas only 18% (very poor and poor) of the area has low potential to groundwater recharge is still important to consider, as it may require different approaches or strategies to improve its suitability. Validation shows that, wells data; (n=38) have water level <5 mbgl (83%), whereas only (n=8) have water less >5 mbgl (17%). This area could be prioritized for more extensive data collection or monitoring to better understand its hydrogeological characteristics. The findings will indeed be helpful for decision-makers in selecting suitable locations for groundwater recharge structures.

Delineation of Groundwater Storage and Recharge Potential Zones Using Multi-Influencing Factors (MIF) Method: Application in Synclinal Coastal Basin of Essaouira (Western High Atlas of Morocco)

Unpredictable rainfall caused by climate change and pollution directly impacts groundwater demand, making the exploitation of groundwater reserves necessary. To achieve this, a study in the synclinal basin of Essaouira (Western High Atlas) used GIS, remote sensing, and the Multi-Influencing Factors (MIF) method, to identify areas ideal for the installation of productive wells. An overlay analysis created a groundwater potential zone (GWPZ) map, showing 30% of the basin with high potential, 51% with moderate potential, and 19% with low to very low potential. The groundwater potential zone map was validated using geophysical surveys, piezometric data, and well water levels, showing a 69.3% prediction accuracy with the ROC curve.

GIS-Based Analytical Hierarchy Process for Identifying Groundwater Potential Zones in Punjab, Pakistan

The quality and level of groundwater tables have rapidly declined because of intensive pumping in Punjab (Pakistan). For sustainable groundwater supplies, there is a need for better management practices. So, the identification of potential groundwater recharge zones is crucial for developing effective management systems. The current research is based on integrating seven contributing factors, including geology, soil map, land cover/land use, lineament density, drainage density, slope, and rainfall to categorize the area into various groundwater recharge potential zones using remote sensing, geographic information system (GIS), and analytical hierarchical process (AHP) for Punjab, Pakistan. The weights (for various thematic layers) and rating values (for sub-classes) in the overlay analysis were assigned for thematic layers and then modified and normalized using the AHP. The result indicates that about 17.88% of the area falls under the category of very high groundwater potential zones (GWPZs). It was found that only 12.27% of the area falls under the category of very low GWPZs. The results showed that spatial technologies like remote sensing and geographic information system (GIS), when combined with AHP technique, provide a robust platform for studying GWPZs. This will help the public and government sectors to understand the potential zone for sustainable groundwater management.

Delineating groundwater potential zones using integrated remote sensing and GIS in Lahore, Pakistan.

Groundwater depletion and water scarcity are pressing issues in water-limited regions worldwide, including Pakistan, where it ranks as the third-largest user of groundwater. Lahore, Pakistan, grapples with severe groundwater depletion due to factors like population growth and increased agricultural land use. This study aims to address the lack of comprehensive groundwater availability data in Lahore's semi-arid region by employing GIS techniques and remote sensing data. Various parameters, including Land Use and Land Cover (LULC), Rainfall, Drainage Density(DD), Water Depth, Soil Type, Slope, Population Density, Road Density, Normalized Difference Vegetation Index (NDVI), Normalized Difference Built-Up Index (NDBI), Moisture Stress Index (MSI), Water Vegetation Water Index (WVWI), and Land Surface Temperature (LST), are considered. Thematic layers of these parameters are assigned different weights based on previous literature, reclassified, and superimposed in weighted overlay tool to develop a groundwater potential zones index map for Lahore. The groundwater recharge potential zones are categorized into five classes: Extremely Bad, Bad, Mediocre, Good, and Extremely Good. The groundwater potential zone index (GWPZI) map of Lahore reveals that the majority falls within the Bad to Mediocre recharge potential zones, covering 33% and 28% of the total land area in Lahore, respectively. Additionally, 14% of the total area falls under the category of Extremely Bad recharge potential zones, while Good to Extremely Good areas cover 19% and 6%, respectively. By providing policymakers and water supply authorities with valuable insights, this study underscores the significance of GIS techniques in groundwater management. Implementing the findings can aid in addressing Lahore's groundwater challenges and formulating sustainable water management strategies for the city's future.

Groundwater level prediction for excessive agricultural irrigation to achieve SDGs: Vulnerability assessment using field-based empirical method

Excessive over-drafting and unsystematic management of groundwater brings different geo-environmental problems; thus precise prediction of groundwater (GW) status in large scale becomes prime concern for efficient GW management. This present study primarily focused on estimating the current groundwater status of agro-rich Murshidabad district using a GIS-based empirical approach including trend analysis of groundwater depth (2001–2021) by using Modified Mann Kendall test (MMKT) and Sen's slope estimator; the most prominent water level fluctuation (WLF) method employed in the estimation of groundwater recharge scenario of the last three decades. The groundwater recharge potential zone (GWRPZ) also delineated through widely used logistic regression (LR) method. The current research depicts that eight CD Blocks and twenty-five CD Blocks out of twenty-six CD Blocks are facing notable declining trend in groundwater depth in pre-monsoon and post-monsoon period accordingly, with a 95% confidence level; the lowering down of groundwater recharge (GWR) also alarming, the recharge amount in 2001, 2011 and 2021 was 210958.70 ham, 240168.80 ham and 201921.90 ham respectively due to variability in rainfall; the predicted GWRPZ shows that 674 (12.6%) Km2 and 1392 Km2 (26.02%) come under very high and high recharge zone which is predominantly found in the eastern and south-eastern part of this study region, validated through most reliable method Receiver Operating Characteristics (ROC) and Area Under Curve (AUC) with 0.954 value. Unsystematic over-drafting of groundwater and intense cropping intensity are severely responsible for this alarming condition. Thus, sustainable groundwater management is essential to fulfil SDG-6 by ensuring SDG-2 and policymakers and planners will be benefited from this study in formulating the proper mitigation measures for this agronomic Murshidabad district.

Effective Use of Catastrophe Multicriteria Decision Analysis in Delineating Groundwater Recharge Potential Zones

Multicriteria decision analysis based on Thom’s [1] Catastrophe Theory (CT) has been applied extensively in solving various social, physical and natural sciences problems. It has become a key tool for identifying the groundwater potentiality of an area with a Geographic Information System (GIS). This paper aimed to apply catastrophe theory effectively by utilizing the standardization formulae suggested by Li et al. [2] and the modified formulae provided by Hongwei Zhu [3]. Depending on the nature of a hydrogeological parameter, CT formulae were chosen to ensure that the least important features also get attention during standardization using Hongwei Zhu's formulae where applicable, which were not possible using Li’s formulae. The standardized values of the features of all the themes obtained using four formulae were sorted in ascending order to estimate the normalized values to ensure that no normalized value of a feature exceeds the others having very close but lower standardized values. The effective use of CT technique was employed in a GIS environment to delineate groundwater recharge potential zones of the middle-west part of Kushtia district, Bangladesh, by integrating influential recharge factors, such as land type, slope, drainage density, distance from surface water bodies, soil permeability, surface clay thickness, rainfall, topographic ruggedness index, topographic curvature index, topographic wetness index and topographic position index. The groundwater recharge potential zones were classified as very good (28.76%), good (32.17%), and moderately good (39.05%) for effective CT technique. But in case of the improper use of CT covering area were 17.24%, 54.05% and 28.71% respectively, and the respective most sensitive factors are rainfall and drainage density. Finally, recharge potential zones were validated using groundwater recharge data with a determinant coefficient of 0.92 and 0.84 for effective and improper use of CT technique respectively.

Groundwater Recharge Potential Index and artificial groundwater recharge in the alluvial soils of the middle Ganga Basin

Recent studies prove the faster depletion of groundwater is a cause of concern in the middle Ganga basin. Most of the groundwater-related studies in the middle Ganga basin deal with groundwater levels and quality aspects. The past studies on groundwater potential are confined to arid and humid zones of India, which leaves ample space for semi-humid to semi-arid, frost-prone, and alluvial region. The basin has alluvial soil due to sediments deposited by the river Ganga. In this study, eight thematic maps were prepared for the assessment of the groundwater recharge potential. These maps are; rainfall, geomorphology, slope, drainage density, lineament density, lithology, Land Use/Land Cover (LULC), and Groundwater Fluctuation (GWF). The weighted overlay of these thematic maps gave the Groundwater Recharge Potential Zone (GWRPZ) map representing the spatial variation of the Groundwater Recharge Potential Index (GWRPI) in the basin, whose value varies from 0.071 to 0.309. A total of 92 artificial groundwater recharge sites have been identified using specialized GIS processes taking into account stream network. The Analytic Hierarchy Process (AHP) based weights classification offers a robust framework for prioritizing and understanding the relative significance of factors affecting groundwater recharge. Alluvial soils are capable of holding large amount of water, and are overlaid by large aquifers. A large number of wells and tube wells have led to the over-extraction of groundwater in the region. This is the reason of the study being carried out despite being a region infested with large aquifers.

GIS-based multi-criteria decision making for delineation of potential groundwater recharge zones for sustainable resource management in the Eastern Mediterranean: a case study

In light of population growth and climate change, groundwater is one of the most important water resources globally. Groundwater is crucial for sustaining many vital sectors in Syria, including industrial and agricultural sectors. However, groundwater exploitation has significantly escalated to meet different water needs especially in the post-war period and the earthquake disaster. Therefore, the goal was this study delineation of the groundwater potential zones (GPZs) by integrating the analytic hierarchy process (AHP) method in a geographic information systems (GIS) within the AlAlqerdaha river basin in western Syria. In this study, ten criteria were used to map the spatial distribution of GPZs, including slope, geomorphology, drainage density, land use/land cover (LU/LC), lineament density, lithology, rainfall, soil, curvature and topographic wetness index (TWI). GPZs map was validated by using the location of 74 wells and the Receiver Operating Characteristic Curve (ROC). The findings suggest that the study area is divided into five GPZs: very low, 21.39 km2 (10.87%); low, 52.45 km2 (26.65%); moderate, 65.64 km2 (33.35%); high, 40.45 km2 (20.55%) and very high, 16.90 km2 (8.58%). High and very high zones mainly corresponded to the western regions of the study area. The conducted spatial modeling indicated that the AHP-based GPZs map showed a remarkably acceptable correlation with wells locations (AUC = 87.7%, n = 74), demonstrating the precision of the AHP–GIS as a rating method. The results of this study provide objective and constructive outputs that can help decision-makers to optimally manage groundwater resources in the post-war phase in Syria.

Modeling groundwater recharge potential zones in the Wadi Yalamlam, Saudi Arabia

Effective management of groundwater resources is vital in arid and semi-arid regions like the Yalamlam Basin. Identifying appropriate places for groundwater artificial recharge is key to addressing water shortages and guaranteeing the long-term viability of aquifers. By combining the Analytical Hierarchy Process (AHP) approach with GIS technology, this research offers a thorough framework for evaluating the potential for groundwater recharge. Data collection for the study includes lineament density, slope, drainage density, rainfall, Land Use/Land Cover (LU/LC), soil, elevation, and TWI, among other crucial variables. In this study, lineament density, slope, drainage density, rainfall, LULC, soil, elevation and TWI are the most sensitive characteristics with relative weights of 30, 23, 16, 11, 8, 5, 4 and 3%, respectively. According to the study’s findings, there are many zones in the Yalamlam region with varying capacities for groundwater recharging. Based on the locations that may be used for groundwater recharge, the study’s findings were categorized into five groups: very high (12.7%), high (23.3%), moderate (29.6%), poor (24.4%), and very poor (10%). The validation of the groundwater protection zones was conducted by using eight wells in the basin. As part of the validation process, the Total Dissolved Solids (TDS) in the boreholes and the groundwater protection zones (GWPZs) were compared. A strong positive correlation was found between them (0.61). The results of this research can be used for the management of groundwater resources and provide valuable information for the creation of policies that focus on specific actions to boost groundwater recharge. These findings may considerably enhance the effectiveness of efforts aimed at implementing customized methods to encourage groundwater recharge. The results suggest that there are substantial prospects for using artificial recharge in groundwater management and planning to tackle the issue of groundwater availability in the study region.

Groundwater recharge potential zone modeling in the Wadi Al-Lith Basin, Saudi Arabia

The management of groundwater resources is crucial in arid and semi-arid regions such as Al-Lith Basin, and therefore, the identification of suitable areas for groundwater recharge is important in solving the problem of water scarcity and ensuring the long-term sustainability of aquifers. In this study, the Analytic Hierarchy Process (AHP) technique, in conjunction with GIS, was applied to locate potential zones for groundwater recharge in the Al-Lith basin. The research methodology includes collecting the essential data, including lineament density, slope, rainfall, drainage density, LU/LC, soil, elevation, and TWI. AHP is used to assign relative weights to different qualities, considering their significance in influencing groundwater recharge. The ArcGIS was employed to process and analyze the weighted layers, which resulted in the creation of a comprehensive map illustrating the potential for groundwater recharge. The study results suggested that the Al-Lith Subbasin has several zones that exhibit different levels of groundwater recharge capability. The results obtained from this study indicated that 12.83% of the basin area has significant groundwater recharge potential zones (GWPZ), ranging from high to very high levels. The groundwater recharge potential zones in the basin are categorized as very poor to poor, covering 19.4% of the area, while the moderate groundwater recharge potential zones represent 67.77% of the basin area. The groundwater protection zones were validated using 19 wells distributed across the basin. The validation findings indicate there is an overlap between the GWPZ classes and the wells in the specified location. Overall, the findings of this study can enhance groundwater resource management and inform policy development for targeted interventions aimed at enhancing groundwater recharge.

A low-cost approach to map natural groundwater recharge potential zones of a tropical watershed with complex land occupation

Groundwater recharge is one of the components of the water cycle and is the most difficult parameter to estimate due to multiple factors that can influence the water percolation until it reaches the water table, such as land use/cover, slope, and soil texture, besides climatic conditions. Given that groundwater is Brazil's most widely exploited natural resource and its significance in sustaining ecosystems, apart from its role in guaranteeing the city's water security, mapping zones of recharge potential is a growing demand for water resources management. This work uses the GIS approach and the water balance (2010–2019) to map the groundwater recharge potential zones of the Adamantina Aquifer in Urânia (São Paulo State, Brazil) delimited on a local scale by the Córrego Comprido watershed. The results showed that 39% of the area has a recharge potential of 165 mm/year or 13% of the average annual precipitation (APPT) for the time, reflecting the gently undulating topography (2–7% slope) with sandy soil texture and shrubby herbaceous cover. Maintaining these same terrain characteristics and changing the land use/cover only, the presence of eucalyptus trees would decrease the recharge potential by 32% (111 mm/y; 9% of average APPT). As another example, the urban occupations would cause a reduction of 80% for the same parameter (33 mm/y; 3% of average APPT). Furthermore, in urban areas, a developing recharge potential value of only 7 mm/year (1% of average APPT) corresponding to sandy lands but with slopes of 7% was observed, demonstrating the primary control of land use/cover and topography in the estimates. The predominant recharge potential value of 165 mm/y correlated with the results of previous recharge studies conducted in Urânia. It demonstrated the versatility of this approach to extrapolate over large areas when required.

Determination of the Groundwater Potential Zones in Babylon Using Remote Sensing &amp; GIS Techniques

Freshwater found underground in the tiny spaces (pores) of soil and rocks is known as groundwater. Groundwater is a valuable resource that considerably contributes to the yearly supplies. To preserve water quality and oversee groundwater systems, evaluation of the potential zone of groundwater recharge is crucial. Using remote sensing and Geographic Information System (GIS) tools, groundwater potential zones are identified. This study proposes to use satellite imagery and the software program (ArcGIS) to find a groundwater potential zone in Babylon City, Iraq. A groundwater map has been created using various data, namely slope, drainage density, lineament density, land use/land cover, geology type, soil type, and rainfall map. All these data are collected using a weighted overlay tool. Five categories were created based on the groundwater results: very poor, poor, moderate, good, and exceptional. The 'good' class covers about 32% of the study area. The current study shows that excellent groundwater class exists in Al-Hindiyah Dam, Al-Muhaweel, Al-Midhatiyah, Al-Kifil, and Al-Mashrua’a. The excellent groundwater class in Al-Shommali covers approximately 198.0054 km2. Certain areas like Al-Musaib Center, Al-Hilla Center, Al-Hashimiyah, and Abi Garaq don't have much groundwater. The moderate and excellent classes cover around 19% of the study area. The main conclusion is that Remote Sensing and GIS have gained recognition as a practical approach to mapping groundwater potential zones due to their ability to integrate diverse spatial data.

Mapping natural groundwater potential recharge zones using GIS-AHP in the Upper Cheliff alluvial aquifer, Algeria

Water scarcity is a big issue in arid and semi-arid regions. This challenge is particularly evident in the Upper Cheliff plain in Algeria, where the alluvial aquifer plays a vital role in drinking water supply and supporting irrigation. This aquifer faces high demand and quality issues. A study was conducted in this context, employing a cartographic approach to assess potential groundwater recharge from precipitation into the alluvial aquifer. The current study aimed at mapping zones with potential natural groundwater recharge zones by applying the Analytic Hierarchy Process (AHP) integrated within a Geographic Information System (GIS) environment, combining various factors that can influence recharge, such as rainfall, surface soil type, slope degree, land use and land cover, unsaturated zone, groundwater depth, and curve number. The map resulting from the analysis indicates that only 22% of the assessed area covers zones with very low and low potential recharge, 35% with moderate potential recharge zones, and 43% with high and very high potential recharge zones. This map reveals that the eastern region of the plain, from the cities of Djendel to Ain Soltane, is moderately to highly favorable for recharge. This is due to the natural recharge from rainfall and watercourse infiltration during dam release periods, excess irrigation water, and recharge from the Miocene sandstone aquifer in areas with direct aquifer contact. A validation process was performed using data from 66 wells distributed in this plain and it indicated that 48 wells exhibited good agreement with the resulting map, while 18 wells showed slight deviations. The results indicate an agreement of 72.72% between expected and exist number value of wells which confirming the good prediction of the AHP technique.

Aquifers Recharge Potentiality Evaluation using Bivariate and Multivariate Statistical Analysis: A Case Study in Malwathu Oya River Basin

An aquifer is a body of porous rock or sediment saturated with groundwater that plays a vital role in the hydrological cycle. Due to rapid population growth and urbanization, these valuable resources face threats like climate changes, pollution, and over-exploitation. Overdraft, where extraction exceeds recharge, can lead to groundwater depletion. Although Sri Lanka is not considered a water- scarce country, it faces rising water demands due to rapid population growth. Especially in dry zones, groundwater is crucial for drinking and agriculture; unauthorized agro-wells exacerbate groundwater issues. Therefore, this research aims to assess groundwater recharge potential zones in Malwathu Oya river basin using Bivariate and Multivariate statistical analysis. Comparing these techniques will lead to the precise identification of potential recharge areas. And this study primarily focuses on the implementation of GIS to find solutions for this kind of challenge without performing field investigations. Therefore, eight conditioning factors; water level, electrical conductivity, lithology, soil, slope, lineament density, drainage density and land use were selected as groundwater recharge influencing factors. The well inventory database consisted of 380 well locations and, out of these, 70% was considered as the training dataset, and the remaining 30% was taken as the testing data set. Groundwater recharge potential maps (GRP) were developed in ArcGIS 10.8, based on the results obtained from Frequency Ratio (FR), Logistic Regression (LR) and their ensemble method. For testing the accuracy of the FR model, test well locations were cross tabulated with the GRP map, and the highest well percentage was achieved in high groundwater recharge potential zone (37.39%). In the LR model, cross-tabulation results showed that 62.61% of testing wells were in the very high potential zones. The ensemble method of FR and LR revealed that 53.04% of test wells fall into the very high potential class. Hence, it can be assumed that LR predictions are more reliable than the FR model. To further validate the LR model and ensemble model, Receiver Operating Characteristics curve method was used. The Area Under the Curve (AUC) values for Success rate curve (SRC) and prediction rate curve (PRC) in LR method were 63% and 57% respectively. In ensemble method, the AUC values for SRC and PRC were 89% and 75%. These results indicate that the LR model is relatively poor estimator, whereas FR and LR ensemble method is relatively good estimator to evaluate groundwater recharge potential in Mulwathu Oya river basin.&#x0D; &#x0D; Keywords: Area under curve, Frequency ratio, GIS, Groundwater recharge, Logistic regression&#x0D;

Cost-Effective Groundwater Potential Mapping by Integrating Multiple Remote Sensing Data and the Index–Overlay Method

The Choushui River groundwater basin (CRGB) in Yunlin County, Taiwan, is a significant groundwater source for the western part of the region. However, increasing groundwater demand and human activities have triggered a potential crisis due to overexploitation. Therefore, groundwater potential zone (GWPZ) maps are crucial for mapping groundwater resources and water resource management. This study employs the normalized index–overlay method and fuzzy extended analytical hierarchy process (FE-AHP) to map GWPZs cost-effectively. The methodology objectively incorporates weightings from various thematic layers by normalizing and correlating parameters with observed groundwater availability (GA). Site-specific observations, including aquifer thickness, depth to the groundwater level, and porosity, inform GA calculations. Seven comprehensive layers derived from remote sensing (RS) data are processed to obtain weightings and ratings for the groundwater potential index (GWPI) in the CRGB. Selected parameters are categorized into hydrological processes, human interventions, geological, and surface profiles. Hydrological processes include precipitation, modified normalized difference water index (MNDWI), and drainage density. Human interventions consist of the enhanced vegetation index (EVI) and normalized difference building index (NDBI). Surface profiles encompass the terrain ruggedness index (TRI) and slope, enhancing the study’s multi-criteria approach. The observed GA validates the GWPZ accuracy, classifying zones into five categories. According to the GWPI of FE-AHP, about 59.56% of the CRGB area can be categorized as “moderate” to “very good” potential groundwater recharge zones. Pearson’s correlation coefficient between GWPI and GA, based on FE-AHP, outperforms the conventional AHP. This RS-based approach efficiently evaluates GA in aquifers with limited wells, highlighting crucial zones in CRGB’s proximal-fan and southeastern mid-fan for informed groundwater management strategies.

IoT-based data and analytic hierarchy process to map groundwater recharge with stormwater.

The sustainable management of groundwater resources in developing countries is often challenging due to limited measurement and monitoring infrastructure to collect data necessary for decision support. To make a contribution towards addressing these challenges, this study investigated the use of Internet of Things (IoT) technology and low-cost sensors to collect the required groundwater-level data and develop a model to map the recharge potential with stormwater. The study focused on two stormwater ponds located in a highly urbanised area in Cape Town, South Africa. A combination of Geographic Information System and analytic hierarchy process was integrated to generate a groundwater recharge potential zone map of the study area. The IoT-based data were used to develop and calibrate a numerical groundwater model in MODFLOW. The study determined that retrofitted stormwater ponds are potential groundwater augmentation zones and can provide opportunity for stormwater recharge in urban areas. Overall, this study highlights the potential of IoT to collect hydrogeological data with low-cost sensors. Data can be collected at high temporal resolution, and the spatial scale can be increased due to availability of low-cost sensors.

Multivariate Assessment of Groundwater Depletion and Recharge Prospect in a Sub-tropical Basin of Eastern India

Abstract The present study aims to highlight the groundwater-stress condition of the Quaternary 一 recent alluvial region escalated by anthropogenic extraction of water resources in the western Bengal Basin (Purba Bardhaman, West Bengal, India). With the rapid development of irrigation technology, high crop yield, water- consumed rice varieties, and high cropping intensity, the farmers of the river basin go to deeper underground aquifers (&amp;gt;180 m bgl) to extract water for summer rice (Boro) cultivation. In this study, the five semi-critical blocks (Mangolkote, Bhatai; Manteswai; Purbasthali II, and Memari II) of Purba Bardhaman district have experienced statistically significant pre-monsoon fall (0.404 m yr- 1 to 1.099 m yr-1) and post-monsoon fall of groundwater level from 0.486 m yr-1 to 2.214 m yr-1. Principal component analysis reflects that annual irrigation draft, annual replenishable groundwater unit, net groundwater availability, Boro rice cultivation area, area to be covered on each day irrigation for Boro, and daily pump discharge required for Boro irrigation are the key factors to escalate groundwater decline. This study reveals that Galsi II, Bardhaman I and II, Katwa I, and Purbasthali I blocks will experience a water-stress or groundwater drought in future. The model of groundwater recharge potential zone shows four principal categories of groundwater prospect area in the basin, viz., poor (0.08 %), moderate (5.78 %), good (68.96 %), and very good (25.18 %). These findings provide the relevant information for planners of groundwater resources to upscale groundwater management procedures and enhance the sustainability of agricultural systems in the study area.