Groundwater Supplies Research Articles

Trend analysis and learning-based groundwater level modelling over a tropical river basin

Groundwater trend analysis and modeling is challenging due to partially explicable factors and unexplained human influence. Hurst index, Sequential Mann-Kendall, and Classical Mann-Kendall test offers a comprehensive groundwater trend analysis. A learning-based approach is developed to model groundwater levels using climatological variables of rainfall and temperature. The study is on 24 locations over Periyar river basin of Kerala, India, for the years 1996-2019, and during January, April, August, and November (JAAN) months. The significant trends were observed at 14 locations in at least one of the JAAN months, which is about 58%. Out of these, 8 locations exhibited positive trend signaling a decline in groundwater supplies. The developed model yielded notable improvements in precision with 50%, 79%, 75% and 83% of the locations in month-wise order. To gauge the model performance, observed and predicted location clusters obtained using k-means clustering are juxtaposed for the years 2017-2019, on both individual and average basis. This assessment indicated only one well transitioning in August, with the average approach resulting in a closer match to the original clustering for most of the wells. These findings shall benefit future stakeholders and policymakers in optimizing resource management strategies over the basin and wider.

Heavy metal intrusion and geospatial analysis of groundwater resources in Isoko North Local Government Area, Delta State, Nigeria.

Abstract This study examined the spatial variation in the intrusion of heavy metals in underground water resources of Isoko North Local Government Area, Delta State, where it conducted a comparative study from ten (10) spatially distributed boreholes, for possible intrusion of the pathogen. The data that was produced were subjected to Heavy Metal Index (HMI) technique to analyse the significant contamination rate in the samples extracted from the study area (using the World Health Organisation Standard and the Nigerian Standard for Drinking Water Quality as the Control Variable). The result of the analysis showed that the undergroundwater there has slightly higher concentrations of Iron and lead than any other parameters. Lead (Ppm) has a range of values of 0.11 to 0.18, with areas like Owhelogho (0.18), Iyede (0.18) and Ellu (0.17) having higher values than others. The range of value for Iron (Ppm) is 0.31 to 0.43, with all the areas having significant values slightly higher than the WHO and NSDWQ standard of 0.3. The study identified places where heavy metals intrusion is prevalent, also a substantial association between pollutant from host rocks and groundwater supplies. The heavy metal index evaluation revealed a class "II" grade, indicating the presence of lead and iron oxide in modest quantities, although its presence is a cause for concern for the well-being of borehole water consumers.The statistics are quite close to the next class on the indexing chart, which is "slightly affected". Any small infiltration raises the stakes to the next level.

A hybrid approach: remote sensing, analytic hierarchy process and geographic information system for groundwater potential mapping in Dediapada, India.

In recent years, the overexploitation of groundwater accompanied by a significant climatic shift has placed a burden on the world's groundwater supply. This has generated a rising need for potential groundwater zones. In recent year the ever-increasing demand for potable water across the world for various groundwater exploration investigation. The present study explores the utility of remote sensing (RS) and geographic information system (GIS) to identify potential water zones in the dry deciduous forest area of Dediapada Taluka, Narmada District, Gujarat, India. Twelve thematic layers of different environmental variables including geology, geomorphology, land use/land cover (LULC), drainage density, lineament density, rainfall, soil, slope, roughness, topographic wetness index (TWI), topographic position index (TPI), and curvature were integrated. GIS mode was subjected to weight analysis using Saaty's 9-point scale. The result was normalized using analytic hierarchy process (AHP), and five distinct groundwater potential zones (GWPZs) were identified namely very high, high, moderate, low, and very low. The area occupied by each category was 6.52%, 3.1%, 60.1%, 14.32%, and 15.99%. The output aids in validation assessment with the existing well data. The groundwater potential zones maps generated using AHP technique can prove beneficial for designing strategies for water management for the present taluka and can be extended to the different talukas also.

Assessment of Antibiotic Resistance in Groundwater Bacterial Strains: A Community-based Study

Background: The microbial quality of private and community water supply from groundwater is mostly not monitored nor assessed by any established government agencies in Nigeria. Contamination by pathogenic and antimicrobial resistant microbial agent, and the potential of resistant genes transfer from environmental bacteria to human pathogens is a major risk for public health in these water systems. Aim: This study was aimed at evaluating the microbiological quality and safety in terms of antibiotic resistance bacterial profile of groundwater sources in a typical peri-urban settlement in Nigeria. Methodology: Bacterial contaminants were isolated by membrane filtration technique, characterized and analyzed using standard microbiological approach. Results: A total of 22 and 8 Gram negative and positive bacteria respectively were isolated. The isolates comprised 7 bacterial genera with Klebsiella and Enterobacter species having the highest incidence of 20% respectively, followed by Bacillus (17%) and least being Shigella with 7% incidence. All the isolates were 100% resistant to cefotaxime, followed by 76.7% and 73.3% resistant to vancomycin and meropenem respectively. The least resistance of 3.3% was against ciprofloxacin. Resistance in borehole storage tank water was highest (80%) against vancomycin followed by 70% for meropenem, while 75% resistance was against vancomycin and meropenem respectively in the well water, Seventy-three percent (73%) of the isolates showed multidrug resistance (MDR) pattern, and a multiple antibiotic resistant index (MARI) ≥ 0.3. Conclusion: The results of this study suggest that groundwater source in the studied community is contaminated with antibiotic resistant bacteria and underscores the public health implication and concern for monitoring of groundwater supply in Nigerian communities.

Spatiotemporal Dynamics of Water Quality: Long-Term Assessment Using Water Quality Indices and GIS

The severe contamination of groundwater supplies in rural areas is a global problem that requires strict environmental measures. Related to this, one of the most important challenges at present is the elimination of local sources of pollution. Therefore, this research examined the local water quality changes following the construction of the sewerage network, under the framework of long-term monitoring (2011–2022) in Báránd, Hungary, using water quality indices and GIS (Geographic Information System) techniques. In order to understand the purification processes and spatial and temporal changes, three periods were determined: the pre-sewerage period (2011–2014), the transitional period (2015–2018), and the post-sewerage period (2019–2022). Forty monitoring wells were included in the study, ensuring complete coverage of the municipality. The results revealed a high level of pollution in the area in the pre-sewerage period. Based on the calculated indices, an average of 80% of the wells were ranked in categories 4–5, indicating poor water quality, while less than 8% were classified in categories 1–2, indicating good water quality. No significant purification process was detected in the transitional period. However, marked changes were observed in the post-sewerage period as a result of the elimination of local sources of pollution. In the post-sewerage period, the number of monitoring wells ranked as excellent and good increased significantly. Additionally, the number of wells assigned to category 5 decreased markedly, compared to the reference period. The significant difference between the three periods was confirmed by the Wilcoxon test as well (p < 0.05). Based on interpolated maps, it was found that, in the post-sewerage period, an increasing section of the settlement had good or excellent water quality. In addition to an assessment of long-term tendencies, the annual fluctuations in the water quality of the wells were also examined. This showed that the purification processes do not occur in a linear pattern but are influenced by various factors (e.g., precipitation). Our results highlight the importance of protecting and improving groundwater resources in municipal areas and the relevance of long-term monitoring of water adequate management policy.

A Simplified Approach of Pumping Rate Optimization for Production Wells to Mitigate Saltwater Intrusion: A Case Study in Vinh Hung District, Long An Province, Vietnam

In the investigation of optimal groundwater extraction in coastal regions, conventional assumptions typically revolve around unconfined aquifers with specified boundary conditions. In such cases, intricate solutions for groundwater management have been documented. However, within extensive delta plains, the extraction wells are frequently drilled in confined aquifers with not much variable-density flow. This circumstance, characterized by paleo-saltwater intrusion, is further complicated by the placement of wells at a considerable distance from the coastal line. As a result, the design and implementation of groundwater supply systems in these areas necessitate strategic groundwater management to optimize groundwater utilization while mitigating the potential risk of saltwater intrusion. Analytical solutions and an optimization problem approach have been applied to address this challenge and solve the differential equations governing confined aquifers with salt–freshwater interfaces. These methodologies provide simplified yet dependable conditions tailored to the study area. A case study conducted in Vinh Hung district, Long An province, is focused on determining the optimal pumping rate for production wells to forestall saltwater intrusion during groundwater extraction. Here, the focus is on the migration of older saltwater towards inland pumped wells, rather than the influence of recent seawater encroachment. The findings contribute valuable insights into achieving an equilibrium between maximizing groundwater utilization and preventing saltwater intrusion in the aquifer systems by a simplified approach.

Impacts of blending advanced treated water and traditional groundwater supply on lead and copper concentrations and microbial diversity in premise plumbing

In response to stresses on water demands, some regions augment conventional drinking water sources with alternative water supplies such as desalinated seawater and reclaimed wastewater. The advanced treatment of wastewater by reverse osmosis, microfiltration, and advanced oxidation processes can produce high quality water for potable uses. However, if not appropriately stabilized, the resulting water can be corrosive to metal-based distribution pipes and plumbing materials. We conducted long-term premise plumbing pipe loop experiments with copper pipes containing lead solder to test the impact of the introduction of advanced treated water on the water quality. Advanced treated water (ATW) originally at low pH (<7) and low alkalinity (<10 mg/L as CaCO3) was stabilized with a calcite contactor before being blended with baseline ground water (BLW). The effects of percentages of ATW on the release of lead and copper and on the changes in the microbial diversity were monitored. Experiments monitored metal release from pipes receiving (1) only BLW, (2) a series of blends of BLW and ATW that gradually increased from 25 % to 100 % ATW, and (3) an abrupt switch from BLW to 100 % ATW. Introducing 100 % ATW dramatically increased lead release and simultaneously decreased copper release. Pipe scale analysis showed that the introduction of ATW had destabilized sulfate-containing pipe scales, which exposed the copper pipe surface to galvanic corrosion. The dissolution of scale material was associated with a significant decrease in sulfate concentration in the 100 % ATW which was in agreement with theoretical solubility calculations. The impact of blending ATW on microbial diversity was studied via 16S rRNA gene amplicon sequencing. The composition of the microbial communities changed significantly after water was in contact with the copper pipes in experiments with both BLW and ATW. The type of water recirculating in the pipes affected the structure of the microbial community. The results from this study can be useful for water utilities that are considering potable reuse as they develop strategies to mitigate any adverse impacts of water quality changes.

Assessment of drinking-water quality in Indigenous Communities of Santa Victoria Este, Argentina

Santa Victoria Este is in the north-east region of Argentina. Historically, socio-economic marginalization and poor governmental assistance have resulted in one of the poorest regions of the country. Over 60% of its population is estimated to belong to indigenous communities. Access to water is mainly through community wells, often lacking adequate infrastructure. With the main objective of empowering indigenous communities in relation to access to safe water, we: 1) established a local laboratory with capacity to analyze microbiological and physical and chemical parameters of water and transfer capabilities to the local community to ensure long-term monitoring; 2) assessed the water quality in 34 communal wells. Results (physical, chemical, metals, and microbiological parameters) show that 70.6% of the groundwater supplies are not safe for human consumption as they exceed the limits established by Argentinian regulation. Microbiological contamination was consistently found in water storage systems (tanks), highlighting the imperative need of water treatment and maintenance. A long-term monitoring program, which includes physicochemical and microbiological parameters, is crucial to ensure the quality of water in these communities and to take appropriate decisions and measures.

Impact of Rainfall and Soil Infiltration on Groundwater Dynamics of Yerekoppi-1 Micro-watershed, Haveri District, Karnataka, India

The amount of water infiltrating the soil surface directly affects the quantity of surface runoff and erosion, and the recharge of both soil and groundwater. Groundwater recharge is an informative indicator of the water located beneath the ground surface. It has a direct impact on renewable supplies of groundwater. In the present study on Impact of rainfall and soil infiltration rate was used for effect on the groundwater level of the Yerekoppi-1 micro watershed (Manakur sub-watershed) in Haveri district of Karnataka state. Average annual rainfall is 700.7 mm and mean potential evapotranspiration is 1541.8 mm. An area of about 888 ha (94.32 %) has clay texture at the surface and 53 ha (5.68%) area has contributing settlement. In Yerekoppi-1 micro- watershed, 38 borewells are there in the vicinity of major stream of the micro- watershed. The mean depth of groundwater levels in the micro- watershed were monitored at a monthly frequency during January-2023 to March-2024. It was found that the maximum average depth of bore wells are about 17.6 mbgl and lowest average depth of borewell about 8.8 mbgl. Soil infiltration rate was measured at upper, middle and lower reaches of the watershed area in the year 2023 and 2024. The majority of the area contributed clay soil. In all the areas of micro-watershed, infiltration rate for clay soil is less than 5 mm/hr. Infiltration rates for all the areas was 1.72- 4.78 mm/hr. Soil infiltration during a rainstorm is closely related to a number of factors such as the intensity and kinetic energy of the rainfall, soil surface conditions and soil properties such as those related to aggregate stability. The groundwater recharge may be improved by growing plantation crop for increasing infiltration rate, construction of percolation tanks and farm ponds in the lower most of the agricultural land.

Spatiotemporal monitoring of groundwater supply and active energy for irrigation practice in semi-arid regions of Tunisia with machine learning

ABSTRACT Semiarid regions are facing overexploitation of groundwater resources to meet irrigation needs. Monitoring the water-energy nexus allows for optimal management of extracted water volumes and consumed energy. The Nabeul region of Tunisia was selected where 14 farmers, whose wells were equipped with smart electricity and water meters (SWEMs), for instant monitoring of pumped water volumes and the electrical energy required for irrigation. Monthly data over a period of eight months were used to study the variations in water volumes and active energy. The analysis of variance classified farmers into four groups based on water volumes and five groups based on active energy. Spatial variability analysis using kriging showed that the northeast zone is the most solicited in terms of water pumping and energy consumption with water volume exceeding 4,000 m3/month and active energy reaching 2,500 kWh/month. The prediction of energy based on water volume using machine learning techniques such as random forest and support vector machine was successfully conducted. The tools generated by the methodology were applied to a chosen case in the region to estimate active energy and validate the results obtained. The implemented framework allows for better management of groundwater resources for irrigation.

The Water–Energy Nexus in 26 European Countries: A Review from a Hydrogeological Perspective

The significance of the interconnection between water and energy, known as the water–energy (WE) nexus, is highly regarded in scientific publications. This study used a narrative review method to analyze the existing WE nexus studies performed before 2024 in 26 European countries. The aim of this study is to provide a comprehensive analysis of the existing WE nexus to identify research gaps and to report a conceptual overview of energy consumption related to groundwater use phases, ranging from the tapping to distribution. This information is valuable as a guideline for any future estimates in this field. The results indicate that the WE nexus in 26 European countries comprises a variety of topics, including the water supply system, wastewater treatment, hydropower, desalination, and biofuel production. Most of the focus has been on fossil fuel production, while water supply and desalination were considered rarely. Italy and Portugal had the largest WE nexus. It is highlighted that there have been no studies on the WE nexus focusing on the groundwater supply system that consider the conceptual hydrological model or hydrodynamic processes. In this work, a view of these aspects was provided by taking into account different hydrogeological and hydraulic scenarios that may affect the amount of energy required for groundwater exploitation. Most scientific publications have focused on quantitative analysis. In the future, it will be necessary for WE nexus models to place a greater emphasis on governance and the implications of the WE nexus approach.

Comparison of groundwater distribution, exchange and storage between cropland and forestland over the past 115 years

ABSTRACT Using the US Geological Survey groundwater model, we compared spatial distribution, flow exchange, and storage of groundwater between cropland and forestland in the Upper Yazoo River Watershed, Mississippi, from 1900 to 2014. Under normal climate, average groundwater head declined 2.7 m in cropland but only 1 m in forestland over the 115 years. The average groundwater flow from forestland to cropland surpassed the reverse flow by a factor of 238, owing to a higher elevation in forestland and intensive groundwater pumping in cropland. Cropland was a net groundwater sink while forestland was a net groundwater source under all climates. Our findings underscore the discernible impacts of climate changes on groundwater storage and suggest that afforestation in the region would be an alternative for saving groundwater resources and supplying more waters to croplands. This study offers valuable insights into groundwater supply planning not only in Mississippi but also in comparable situations worldwide.

Hydrogeophysical mapping of paleochannels for water security in Bhawanigarh Block, District Sangrur, Punjab, India

Paleochannels, ancient buried riverbeds, offer significant potential for groundwater management and contribute to achieving the Sustainable Development Goals (SDGs), particularly those focused on clean water (SDG 6) and sustainable ecosystems (SDG 15). These channels, formed when rivers change course due to natural processes or human activities, become filled with loose, permeable sediments like sand and gravel, making them natural reservoirs capable of storing large volumes of groundwater. This characteristic makes paleochannels invaluable for enhancing water security in arid and semi-arid regions.The present study, conducted in the Bhawanigarh block of Sangrur District, Punjab, focuses on mapping paleochannels for Managed Aquifer Recharge (MAR) using Electrical Resistivity Survey techniques. A total of 37 Vertical Electrical Soundings (VES) were performed with a Computerized Resistivity Meter, and the findings were validated using well-logging, exploration data, historical aerial photographs, and satellite imagery. Identifying and mapping these paleochannels enable targeted groundwater recharge efforts, enhancing the sustainable management of water resources.By strategically utilizing paleochannels for artificial recharge, excess surface water can be directed into these hidden reservoirs, effectively replenishing groundwater supplies. This approach supports agricultural and drinking water needs and strengthens resilience against climate change impacts, aligning with SDG 13 (Climate Action). Moreover, the careful management of these ancient channels promotes the sustainable use of natural resources, contributing to the overall goals of environmental sustainability and water security outlined in the SDGs.

The role of farm subsidies in changing India’s water footprint

Dwindling groundwater supplies threaten food security and livelihoods. Output subsidies for farmers are a ubiquitous agricultural policy tool, yet their contribution to growing groundwater stress remains poorly quantified. We show how output subsidies guaranteeing the purchase of crops at higher than market prices may have contributed substantially to declining water tables in India. Our analysis suggests that these policies may have led to a 30% over-production of water intensive crops. In the northwestern state of Punjab, rice procurement can potentially account for at least 50% of the groundwater table decline over 34 years. In the central state of Madhya Pradesh, wheat procurement adopted in the late 2000s appears to have driven a 5.3 percentage point increase in dry wells and a consequent 3.4 percentage point increase in deep tubewells. These results suggest that well-intentioned but poorly designed subsidies can impose harmful externalities on the environment and undermine long-term sustainable development.

Heavy Metal Identification in Water Resources and the Surrounding Environment of the Cirasea Riparian Zone, Indonesia

The Cirasea River can provide water for both the Bandung basin and agricultural irrigation. Intensive agriculture, industry, and land use changes could have an impact on water quality. The purpose of this study is to look at the origins of heavy metals in riparian water resources. Heavy metal analysis was performed on 13 groundwater and river water samples. Heavy metals in water sources were compared with sediment and soil. The samples were analyzed for heavy metals using an AAS instrument. The research method employs statistical, geographical, and heavy metal pollution index (HPI). The HPI for river water was 131, whereas groundwater was 93. River water with an HPI value of more than 100 is highly polluted, indicating that it is unsafe for human consumption and has negative health consequences. Data verification with heavy metals in sediments reveals the presence of heavy metals coming from geogenic circumstances in various locations in the upstream area. Heavy metals in downstream areas result from geological factors and anthropogenic activities in the surrounding area. The long-term effects of heavy metal pollution along the riparian zone will become apparent. More research is needed on communities that depend on groundwater supplies along the Cirasea watershed.

Delineation of fresh groundwater potentiality zones in saline coastal aquifers, Southwest Bangladesh using remote sensing and GIS approaches.

Bay of Bengal in southern Bangladesh is a major source of water from coastal aquifers, but prone to contamination by seawater intrusion,making climate-vulnerable populations and economies unfit for potable, agricultural water, adopting crops, etc. The study area located in Khulna district lies in the southwestern coast of the country is among the most vulnerable due to its salinity issues. Therefore, this study identified fresh groundwater potential zones in the southwestern coastal zones of the country suited for community usage helping coastal peoples meet their demands. This study focused on twelve thematic layers employing remote sensing and GIS with analytical hierarchy process. Here, groundwater salinity is 84% brackish to saline over 70% of the region [electric conductivity: 295-16,295 micro-Siemens/cm]. However, groundwater chloride in 88% signifies a slightly to medium salty zone. The annual average rainfall reduced surface water infiltration in 75% of the area with little to very slightly soil salinity. The fresh groundwater resource zone has classified based on its potentiality as: very high (0.52%)-for drinking, agricultural irrigation, or industrial work; high (25%)-marginal salinity suitable for agricultural or industrial uses; low (11%)-low salinity, but usable for high salt tolerant crops in irrigation; and very low (64%)-very high groundwater salinity, and not suitable for human consumption and community uses. Finally, this study will help develop sustainable groundwater resources in the coastal region and a fresh groundwater supply plan in saline-prone areas.

A Multi-criterian Approach to Identify Groundwater Potential Zones in the Subarnarekha River Basin Using Integrated Analytical Hierarchy Process and Geospatial Technology

The intense extraction of groundwater and changing climate patterns have strained global groundwater supplies. As the demand for drinkable water rises worldwide, assessing groundwater availability and aquifer output becomes increasingly important. Geographic information systems (GIS) are being used more frequently for groundwater exploration due to their speed and provision of preliminary data. This study focuses on mapping groundwater availability in a minor tropical river basin in India, using a combination of GIS and the analytical hierarchy process (AHP). Ten thematic layers were generated and analyzed, including Geology, Geomorphology, Land use and land cover (LULC), Lineament density, Drainage density, Rainfall, Soil type, Slope, Topographic Wetness Index ( TWI), and curvature to delineate groundwater potential zones. AHP was employed to assign weights to each category based on their water retention properties. The resulting map was validated against existing groundwater data, demonstrating an accuracy of approximately 85%. The groundwater potential zones were classified as high, moderate, and, low. The moderate potential zone covered 59% of the basin, while the low and high potential zones constituted 29% and 11% respectively. High and low potential regions were limited to small sections of the basin. In conclusion, this research successfully mapped the groundwater availability in the Rarhu River watershed using GIS and AHP. The findings highlight the distribution of different groundwater potential zones, providing valuable information for sustainable water resource management in the area.

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.

Will there be water? Climate change, housing needs, and future water demand in California

Climate change in California is expected to alter future water availability, impacting water supplies needed to support future housing growth and agriculture demand. In groundwater-dependent regions like California's Central Coast, new land-use related water demand and decreasing recharge is already stressing depleted groundwater basins. We developed a spatially explicit state-and-transition simulation model that integrates climate, land-use change, water demand, and groundwater gain-loss to examine the impact of future climate and land use change on groundwater balance and water demand in five counties along the Central Coast from 2010 to 2060. The model incorporated downscaled groundwater recharge projections based on a Warm/Wet and a Hot/Dry climate future from a spatially explicit hydrological process-based model. Two urbanization projections from a parcel-based, regional urban growth model representing 1) recent historical and 2) state-mandated housing growth projections were used as alternative spatial targets for future urban growth. Agricultural projections were based on recent historical trends from remote sensing data. Annual projected changes in groundwater balance were calculated as the difference between land-use related water demand, based on historical estimates, and climate-driven recharge plus agriculture return flows. Results indicate that future changes in climate-driven groundwater recharge, coupled with cumulative increases in agricultural water demand, result in overall declines in future groundwater balance, with a Hot/Dry future resulting in cumulative groundwater decline in all but Santa Cruz County. Cumulative declines by 2060 are especially prominent in San Luis Obispo (−2.9 to −5.1 Bm3) and Monterey counties (−6.5 to −8.7 Bm3), despite limited changes in agricultural water demand over the model period. These two counties show declining groundwater reserves in a Warm/Wet future as well, while San Benito and Santa Barbara County barely reach equilibrium. These results suggest future groundwater supplies may not be able to keep pace with regional demand and declining climate-driven recharge, resulting in a potential reduction in water security in the region. However, our county-scale projections showed new housing and associated water demand does not conflict with California's groundwater sustainability goals. Rather, future climate coupled with increasing agricultural groundwater demand may reduce water security in some counties, potentially limiting available groundwater supplies for new housing.

Addressing water security challenges through groundwater recharge for revival of Kanari River using AHP and geospatial techniques

Artificial recharge of groundwater has been recognized as a promising option for sustaining groundwater supplies and ensure water security for the ever rising population. With the aid of geospatial and multi-criteria decision analysis methodologies, the current study's scope aids in evaluating groundwater potential zones and locating suitable zones and sites for groundwater recharge for the revival of the Kanari River. A pragmatic methodology was suggested in this study for implementing water harvesting structures for river revival and estimation of water demand, pumping, and recharge. The geometric mean and the normalized weight for individual features were specified using the AHP in a GIS environment. All the different features/datasets were overlaid, and possible groundwater zones were revealed using AHP. Integrated maps were used to identify the groundwater recharge zone and locations for establishing artificial recharge structures within the Kanari River system. Ultimately, the domestic water demand, agriculture water use, pumping, and livestock water demand were estimated for water budgeting, and based on this data, the water availability was calculated. Based on the study results, the water demand of the Kanari River watershed was estimated to be 732 MCM. Taking into consideration the supply and demand scenarios, the pumping overdraft of the Kanari River watershed was found to be 423 MCM, and the proposed additional recharge through the planned conservation structures was estimated to be 859 MCM. So, even if pumping overdraft is considered, this additional groundwater recharge can fulfill the local demand, help maintain the river flow, and ensure water availability and security in the region.