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The article presents semi-analytical mathematical models to asses (1) enhancements of seepage from a canal and (2) induced flow from a partially penetrating river in an unconfined aquifer consequent to groundwater withdrawal in a well field in the vicinity of the river and canal. The nonlinear exponential relation between seepage from a canal reach and hydraulic head in the aquifer beneath the canal reach is used for quantifying seepage from the canal reach. Hantush's (1967) basic solution for water table rise due to recharge from a rectangular spreading basin in absence of pumping well is used for generating unit pulse response function coefficients for water table rise in the aquifer. Duhamel's convolution theory and method of superposition are applied to obtain water table position due to pumping and recharge from different canal reaches. Hunt's (1999) basic solution for river depletion due to constant pumping from a well in the vicinity of a partially penetrating river is used to generate unit pulse response function coefficients. Applying convolution technique and superposition, treating the recharge from canal reaches as recharge through conceptual injection wells, river depletion consequent to variable pumping and recharge is quantified. The integrated model is applied to a case study in Haridwar (India). The well field consists of 22 pumping wells located in the vicinity of a perennial river and a canal network. The river bank filtrate portion consequent to pumping is quantified., (© 2014, National GroundWater Association.)

Quantification of the amount of the exchanged water between the surface water and a confined aquifer is a basic step in water balance and environmental hydraulics. The hydraulic connection between a surface water and a confined aquifer may occur through different recharge variations. The current research presents new analytical solutions for confined aquifer response to recharge variations and different inflow distributions. Different cases were studied, where a constant piezometric head is applied at the right boundary of the 2D confined aquifer plane and various distributions of water inflow through the recharging windows are considered on a part and/or parts of the left boundary. Finally, a uniform water inflow distribution on parts of the left boundary and a uniform distribution of water outflow at the right boundary was considered. Both steady and unsteady state problems can be solved using proposed equations. The performance of developed analytical solutions was examined compared to the numerical finite difference modeling. The results show reasonable precision of the developed analytical solutions. The developed solutions can be used as a benchmark to verify numerical approaches with similar boundary conditions., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

The objective of this paper is to investigate and analyze the silting and subsequent aggradation of the irrigation canals in Zˇitný Ostrov (Rye Island). The irrigation canal network, located in Southern Slovakia, was built to provide for irrigation water and drainage in the region. The water level in the irrigation canals and groundwater level in Zˇitný Ostrov area affect each other. Because of this mutual interaction, it has been necessary to evaluate the impact of silting in the canal network due to the presence of the alluvials. Water surface elevations in Danube River affect groundwater infiltration from the Zˇitný Ostrov aquifer, in and out of the canals, and causes fluctuation of the flow in the canals. The amount of groundwater infiltration is a function of the silt hydraulic conductivity. Tests were done in 1993 and 2004 to measure the silt thickness and granularity at 166 measurement points along approximately 77 km of the canal network. This paper discusses the change in silt thicknesses and silt volume in the canals as they built up over an 11-year period. As a secondary goal of the paper, the silt granularity and hydraulic conductivity was determined. The results of our research are useful in establishing the canals’ maintenance program. The regional planning commission will use the study to forecast silting in the future. [ABSTRACT FROM AUTHOR]

Agricultural production of high value crops in Chile's Central Valley is highly dependent on surface and groundwater resources. They are connected and together form an integrated hydrological system, the individual components of which have to be studied. This research is addressed to answering two questions: 1) to what extent do irrigation and canal seepage contribute to groundwater recharge and 2) what is the influence of the interactions between the Cachapoal River and ground water. The study was carried out from 2003 to 2007 in Peumo Valley (34.3° S, 71.3° W). In winter, the irrigation canal network intercepts and diverts surface runoff, which flows to flat areas and recharges groundwater. In summer, infiltration from the canals recharges the aquifer directly and partially compensates for water uptake from plants and evaporation. The effects of both interactions keep groundwater at a relatively constant level over the whole year. The water balance of the valley is strongly affected by agricultural practices, groundwater recharge mainly originating from irrigation loss (22%) and canal seepage (52%). It is important to know how management decisions, such as change in irrigation practices or canal lining, can affect the hydrological system and agricultural production within the valley. [ABSTRACT FROM AUTHOR]

Managed aquifer recharge (MAR) is a promising adaptation measure to reduce vulnerability to climate change and hydrological variability. However, in areas where the basin is highly polluted, densely populated, and intensely cultivated, implementing suitable MAR strategies is a significant challenge. This study used a geographic information system-based multicriteria decision analysis (GIS-MCDA) approach to delineate the MAR potential sites using seven thematic layers describing surface and subsurface features. Further, basin-specific MAR approach was developed using information such as polluted water areas, canal network distribution for water supply, and cropping patterns. The results of this study indicate that only 17% of the area is highly suitable, while 54% and 29% were found moderately suitable and unsuitable for the MAR approach. Since most highly and moderately suitable sites were falling in the agricultural areas, agricultural-based MAR (AgMAR) was considered a preferred option. AquaCrop model for sugarcane was developed considering excess canal water supply during the grand growth stage to understand the AgMAR potential in the study area. It was observed that the potential recharge under normal irrigation scenarios varies from 135.5 to 272 mm/year, which can be increased through AgMAR up to 545 mm/year depending on the water availability for excess irrigations. This study provides an improved understanding of the parameters that should be considered for MAR site selection and post-GIS-MCDA analysis to assess the basin-specific MAR strategy., (© 2023. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

This study examines the proportional contribution of snow/ice melt, rainfall, and groundwater to Sutlej River discharge at various locations. Sutlej River is a major tributary of the Indus River system and an important water supply source for irrigation through the canal network in northwest India. Here, we used hydrograph separation and associated uncertainty and applied the snowmelt runoff model (SNOWMOD) to estimate the contribution from different water sources to the Sutlej River. We used δ18O and electrical conductivity values of different waters for the hydrograph-separation approach. The first-order Gaussian error propagation and Monte-Carlo simulation are used to assess the accuracy. The estimated contribution at Rampur is ~ 62.7% (snow/ice melt), 18.7% (rainfall), and ~ 18.4% (groundwater); for Ropar is 59 ± 2% (snow/ice melt), 23 ± 2% (rainfall), and 18 ± 2% (groundwater); and for Yusufpur, 25 ± 3% (snow/ice melt), 39 ± 3% (rainfall), and 36 ± 2% (groundwater) during July–December 2013. The findings from the hydrograph-separation and SNOWMOD analysis established a fundamental understanding of the hydrological processes in the Sutlej River system, providing valuable baseline data essential for developing sustainable water resource management strategies. [ABSTRACT FROM AUTHOR]

The effects of anthropogenic water use play a significant role in determining the hydrological cycle of north India. This paper explores anthropogenic impacts within the region's hydrological regime by explicitly including observed human water use behaviour, irrigation infrastructure and the natural environment in the CHANSE (Coupled Human And Natural Systems Environment) socio‐hydrological modelling framework. The model is constrained by observed qualitative and quantitative information collected in the study area, along with climate and socio‐economic variables from additional sources. Four separate scenarios, including business as usual (BAU, representing observed irrigation practices), groundwater irrigation only (where the influence of the canal network is removed), canal irrigation only (where all irrigation water is supplied by diverted surface water) and rainfed only (where all human interventions are removed) are used. Under BAU conditions the modelling framework closely matched observed groundwater levels. Following the removal of the canal network, which forces farmers to rely completely on groundwater for irrigation, water levels decrease, while under a canal‐only scenario flooding occurs. Under the rainfed‐only scenario, groundwater levels similar to current business‐as‐usual conditions are observed, despite much larger volumes of recharge and discharge entering and leaving the system under BAU practices. While groundwater abstraction alone may lead to aquifer depletion, the conjunctive use of surface and groundwater resources, which includes unintended contributions of canal leakage, create conditions similar to those where no human interventions are present. Here, the importance of suitable water management practices, in maintaining sustainable water resources, is shown. This may include augmenting groundwater resources through managed aquifer recharge and reducing the impacts on aquifer resources through occasional canal water use where possible. The importance of optimal water management practices that highlight trade‐offs between environmental impact and human wellbeing are shown, providing useful information for policy makers, water managers and users. © 2019 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Groundwater level rising in the plain of Mian-Ab located in Khuzestan Province, southwestern Iran, is one of the major threats to this region. Continuous recharge of the aquifer through returned water from irrigation canals as well as the spread of fine sediment particles along with other hydrological and hydrogeological factors have led to a decrease in groundwater quality and waterlogging of the areas under cultivation in the region. This study evaluated nine important hydrological and hydrogeological parameters using the Analytical Hierarchical Process method to detect the vulnerable zones in Mian-Ab aquifer regarding the groundwater level rising. The vulnerability map showed that some parts of northern, central and southern lands in the study area were in the medium and high waterlogging vulnerability. The groundwater flow in the aquifer was then simulated using the MODFLOW model to validate and verify the vulnerability map of the study area, and also to predict the aquifer behavior in case of developing an irrigation canal network in future. The model was calibrated from September 2016 to September 2017 in the unsteady state conditions with 0.94 RMSE error. The model was first executed with a 20 percent increase in the net recharge rate. Then, the vulnerability map was confirmed and validated in the MODFLOW model, given that the increase in groundwater level occurred precisely in the zones identified in the vulnerability map. In the next step, to evaluate the development of the irrigation network in the region, the future conditions were simulated therein. The model showed that the head would increase significantly about 2 to 4 m in the same zones where the vulnerability map detected, and the recharge rate increased about 13.28 MCM through the returned water of the future canals considering their dedicated specific flow rates. It is thus recommended that the network development program and net recharge allocation be adequately managed to prevent environmental problems in the southern parts of the study area [ABSTRACT FROM AUTHOR]

Groundwater is one of the most vital sources of irrigation in semi-arid regions of India, and in Punjab, India this resource is being highly exploited due to intensive agricultural practices. In the present study, groundwater quality in Bathinda district of Punjab, India was evaluated to know its suitability for drinking and human health risk associated with direct use of groundwater. To examine the suitability of groundwater for drinking purposes, drinking water quality index (DWQI) approach was used. Non-carcinogenic human health risk associated with the presence of fluoride and nitrate in groundwater was evaluated for the adults and children, through dermal and oral ingestion exposure pathways. Further, to know the processes governing the aquifer geochemistry, Gibbs plot, interionic relationships and principal component analysis were carried out. The results of the present investigation revealed that quality in 73% groundwater samples was not suitable for direct consumption. The results of hazard index (HI) indicated that 91% samples in case of men and 95% samples in case of women and children have HI value more than 1. There is a high non carcinogenic human health risk potential due to direct use of groundwater, and children and women are more prone to this risk. The inter-ionic relationships exhibited that evaporation processes due to semi-arid hot type climate, silicate weathering, shallow groundwater level, interaction of canal and ground water along with the agricultural return flow mainly controlled the groundwater chemistry in the area under investigation. [ABSTRACT FROM AUTHOR]

Groundwater in north India remains a vital food and water security resource for more than one billion people. Both summer monsoon drying, and winter warming pose considerable challenges for rapidly declining groundwater. However, their impacts on irrigation water demands and groundwater storage under the observed and projected future climate remain unexplored. Using in situ observations, satellite data, and a hydrological model that considers the role of irrigation and groundwater pumping, we show that summer monsoon drying and winter warming accelerate groundwater depletion in north India during the observed climate, which will continue in the projected future climate. Summer monsoon precipitation has significantly (P‐value = 0.04) declined (∼8%) while winters have become warmer in north India during 1951–2021. Both satellite (GRACE/GRACE‐FO) and hydrological model‐based estimates show a rapid groundwater depletion (∼1.5 cm/year) in north India with a net loss of 450 km3 of groundwater during 2002–2021. The summer monsoon drying followed by winter warming cause a substantial reduction in groundwater storage due to reduced groundwater recharge and enhanced pumping to meet irrigation demands. Summer monsoon drying and winter warming will continue to affect groundwater storage in north India in the future. For instance, summer monsoon drying (10%–15% deficit for near‐far periods) followed by substantial winter warming (1–4°C) in the future will further accelerate groundwater depletion by increasing (6%–20%) irrigation water demands and reducing groundwater recharge (6%–12%). Groundwater sustainability measures including reducing groundwater abstraction and enhancing the groundwater recharge during the summer monsoon seasons are needed to ensure future agricultural production. Plain Language Summary: Groundwater in north India is facing rapid depletion due to summer monsoon drying and winter warming. The decline in summer monsoon precipitation and warmer winters have led to major droughts, resulting in a massive loss of groundwater between 2002 and 2021. Summer monsoon drying coupled with winter warming climate will increase irrigation water demands and reduce groundwater recharge. This necessitates the implementation of groundwater sustainability measures to ensure future agricultural production during monsoon droughts. Key Points: Examined the role summer monsoon drying and winter warming on groundwater storage in IndiaRapid groundwater depletion (∼1.5 cm/year) resulted in a net loss of 450 km3 of groundwater during 2002–2021Summer monsoon drying followed by substantial winter warming under the warming climate will further accelerate groundwater depletion [ABSTRACT FROM AUTHOR]

The present study attempts to delineate groundwater zones using multi-criteria decision analysis based on land-use/cover pattern, groundwater table, and groundwater quality for both domestic and agricultural use in the Bist-Doab region of Punjab, India. The region has about 71% land under agricultural activities, 12% under built-up area, 7% under forest cover, 5% under tree plantation, 3% under water bodies, and the remaining 2% under open area. As far as the groundwater table is concerned, about 8% of the region has a groundwater table below 30 m, mainly around the urban areas of Jalandhar. Qualitatively, the groundwater has not been found suitable for domestic consumption in areas around Jaijjon, Taunsa, Jalandhar urban agglomeration, Shahkot, and Nakodar blocks. In 10% of areas of Sultanpur Lodhi, Shahkot, Nakodar, Phagwara, and Bhulath, the groundwater has been found unsuitable for irrigation. The groundwater zoning resulting from the stacking of these thematic layers reveals that about 20% of the region has a poor quality of groundwater, mainly occupying the areas of urban agglomeration of Jalandhar, Phagwara, Hoshiarpur, parts of Sultanpur Lodhi, Mahilpur, and Balachaur blocks. In the urban cluster of Jalandhar, Phagwara, and Hoshiarpur, a high level of urbanization and industrialization is responsible for the poor quality of groundwater. The untreated discharge of industrial wastes from pharmaceutical companies is responsible for poor quality of groundwater in the Balachaur block of Shaheed Bhagat Singh Nagar district. Further, the groundwater of the remaining 80% of the region is of better quality, but that too is vulnerable to groundwater deterioration due to various anthropogenic factors, such as higher groundwater extraction, intensive application of chemical fertilizers in the fields, and prevailing cropping pattern. The study suggests certain groundwater management strategies, viz. comprehensive planning of land-use/cover pattern, change in cropping pattern, change in prevailing agricultural practices such as water-saving irrigation, shift to rain-fed irrigation, minimum use of chemical fertilizers, promotion of organic farming, treatment of urban and industrial wastes, rainwater harvesting, artificial recharge, regular monitoring, legal restriction on water use, and energy pricing, which can be efficient in dealing with the emerging problems of groundwater resources in the region. [ABSTRACT FROM AUTHOR]

Several stochastic analyses were conducted in Miami-Dade County, Florida, to evaluate the effects of wellfield withdrawal on aquifer water levels, canal stage, and canal flow. Multiyear data for withdrawals at four water-supply wellfields, water levels at the S-121 canal control structure and groundwater head at a nearby monitoring well were used to determine the interrelation between wellfield withdrawals and water levels in the canal and aquifer. A spectral analysis was performed first on the wellfield withdrawals, showing similar patterns of fluctuations, but no well-defined seasonality. In order to compare water-level response with withdrawals at each wellfield, the intercorrelation effects between wellfields was removed through a 'causal chain' approach where the inter-wellfield correlation is used to isolate the wellfield/water-level correlation. Most computed correlations have magnitudes less than 5 percent, but with statistical significance above 90 percent. Results indicate that withdrawals from the wellfields most distant from the canal had no significant correlation to the canal levels. However the highest correlation was not at the wellfield closest to the canal, but at the two wellfields at the intermediate distance that have higher withdrawal rates. The hydraulic interconnectivity of the canal with the rest of the canal network, covering the study area, allows the canal equalizes with all connected canals. This explains why proximity to a particular canal location does not appear to be as important a factor as the withdrawal rate. Groundwater levels are more highly correlated to a wellfield on the same side of the canal, and to pumping wells in the same wellfield on the same side of the canal. This indicates that canals are an effective barrier and source/sink for the groundwater. Further nonlinear correlation analysis indicates that high withdrawal rates disproportionally affect water levels and are the predominant effect on the canal., (Published by Elsevier Ltd.)

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Saline water intrusion is degrading water quality in the channelized coastal wetlands of the southern Albemarle estuarine system (AES). The source, transport and fate of the saline water in the southern AES was determined by monitoring specific conductivity and water levels in small artificial channels, the Alligator River, the Alligator-Pungo Canal and the groundwater system for ~12 months. Results indicate that water levels are affected by wind tides which trigger the movement of saline water into the interior of the wetlands via the small canals. The wind tides are mostly driven by episodic southerly winds pushing saline water into the canal network and the groundwater regime proximal to the Alligator River. The saline waters persist in the canals as long as the wind tide events last. Specific conductivities from canals and groundwater are shown to be unexpectedly higher closer to the source of the Alligator River than toward the Albemarle Sound, suggesting that the large Alligator-Pungo Canal facilitates the northward migration of saline water from the Pamlico Sound to the Alligator River. Overwash and reversals in the flow directions between groundwater and surface water bodies suggest that saline water that is present during wind tide events may migrate into the groundwater system from surface water bodies. The results of this study reveal that whereas the large Alligator-Pungo Canal channels saline water to the AES, small artificial channels may also play significant roles in degrading water quality in the interior of channelized coastal wetlands. [ABSTRACT FROM AUTHOR]

Waterlogging is a complex phenomenon, the severity of which depends on a number of natural as well as anthropogenic factors. The present study pertains to the evaluation of control exerted by various factors, viz geomorphology, relief, groundwater fluctuation, rainfall, catchment area and canal-road network density, on waterlogging in the north Bihar region of Gangetic Plains. Satellite images IRS P6 LISS III acquired in the years 2005 and 2006 were used to map temporal variability in surface waterlogging which revealed a reduction of 52 % in the waterlogging area during the pre-monsoon. The seasonal groundwater fluctuation was examined using 2005-2006 pre- and post-monsoon water level data. It clearly indicated that a large portion of the area was also under highly critical groundwater level occurring at a depth of less than 1 m belowground surface during the post-monsoon periods. The percentage of waterlogged area per square kilometer in each geomorphological unit clearly depicts that the Kosi megafan (Lower), because of a high density of paleochannels, comprises the highest post-monsoon waterlogged area. The Tropical Rainfall Measuring Mission (TRMM) data were analyzed for the period 1998-2009 to examine the spatial variability of rainfall over the entire catchment during the monsoon period. The high incidence of post-monsoon surface waterlogging delineated through satellite data and high average rainfall (>1,100 mm) in the same area indicates a positive relationship between rainfall and surface waterlogging. Waterlogging is more prominent in the lower relief zones, but anomalous relative rise in waterlogging within 40-50 m of relief zone was attributed to anthropogenic factors primarily related to the development of canal network. [ABSTRACT FROM AUTHOR]

Groundwater conditions in the multi-aquifer system in the Krishna River Delta, India, were studied through an integrated approach using hydrochemical, hydrogeological and isotopic techniques. This study was taken up because of the reported seawater intrusion into the groundwater system of this agriculturally rich region. The results, of hydrochemistry and environmental tritium including the radiocarbon dates, indicate that the origin of salinity in the aquifer systems is due to palaeo-geographical conditions. The salinity front is observed to be at 25, 30 and 50 km distance in shallow, intermediate and deeper aquifers respectively from the coast. The modern irrigation practices using intensive canal network has led to refreshening of the aquifer systems. The extent of refreshening has been mapped using hydrochemistry and environmental tritium. The recharge of groundwater by the canal system can be expedited by developing the canal network in the area having high potential for groundwater recharge. This will result in further reduction of salinity in the Krishna delta region. Further, Cl-/Br- ratio and stable isotopes (δ 18O and δ D) have been used to study the aquifer- aquifer interconnectivity and to identify perched aquifers within the study area. [ABSTRACT FROM AUTHOR]

Water resources management and sustainable development depend on the quality of groundwater as a major source of fresh water. As a result of rising water demand in emerging nations and overexploitation, groundwater quality has declined globally in many aquifers. One of the most significant elements that lower the quality of the groundwater is salinization. This review is to provide an overview of various materials that are used in the design and development of innovative chitosan-based nanocomposite polymeric membranes for desalination. Biodegradable, non-toxic, affordable, and easily available, with film-forming ability and poly-functionality, chitosan is an ideal material for a sustainable future. Membrane preparation for desalination using chitosan helps to provide antibacterial and antioxidant activities, great chelating capabilities, and strong adsorption capacity. In this research, we discuss a variety of concepts concerning the different sources of elevated salinity and available desalination methods. A comprehensive framework was also developed to understand the leaching and percolation of salt in groundwater, an essential component of managing risks and ensuring safety. Additionally, we explain the various remediation strategies for reducing groundwater's salt concentration and explore the best method for desalination specifically focused on chitosan. [ABSTRACT FROM AUTHOR]

Current hydrological models still face difficulties in accurately simulating vadose zone (VZ) hydrological processes in arid watersheds with shallow groundwater environments. Therefore, this article introduces a new mechanistic VZ module coupled with an improved groundwater‐balance (GWB) module to enhance the capabilities of the well‐known Soil Water Assessment Tools (SWAT) model. The main improvements and features of the modified SWAT model (M‐SWAT) include: a numerical VZ module to accurately simulate soil water‐salt transport under variably saturated conditions by solving the head‐formed Richards' equation and advection‐dispersion equation; a GWB module (on a sub‐basin scale for shallow aquifer) coupled with VZ module by proposing an effective way of boundary information exchanges; and a more reasonable water‐salt stress functions (i.e., based on matric head and osmotic head) to calculate root water uptake and plant growth. The M‐SWAT was then tested and evaluated with two‐year observation data from the Yangchang canal command area (YCA, an experimental site) and the Jiyuan Irrigation System (Jiyuan, region‐scale), located in the arid upper Yellow River basin of northwest China. The model produced a good agreement between the simulated and observed data in both calibration and validation with sufficiently small root mean square error (RMSE). The determination coefficient (R2) was greater than 0.51, 0.36, and 0.87 in simulating the soil water‐salt dynamics, groundwater depth fluctuations, and leaf area index development, respectively. Case testing also proved that the M‐SWAT had sufficient computational efficiency and stability for regional application. Further comparisons with previous studies indicated that the M‐SWAT could more accurately and rationally simulate the soil water‐salt dynamics and their interactions in arid watersheds with shallow groundwater tables. [ABSTRACT FROM AUTHOR]

Using an integrated analytical hierarchy process, remote sensing and geographic information system techniques, the current study aims to map and identify the potential groundwater zones of Kurukshetra District of Haryana, which is located in the Ghaggar and Upper Yamuna Basins in India. This is done in the context of a significant change in the use of groundwater pattern, with respect to its continuously increasing demand due to the growing population, expansion of area under irrigation and related economic factors. The amount and quality of groundwater are anticipated to be impacted by anthropogenic activities as well as natural factors such as geomorphology, soil type, lithology and rainfall variance owing to a changing climatic scenario. The potential index of groundwater for this study was calculated by using nine important factors, including geomorphology, rainfall, soil type, depth to groundwater level, lithology, land use land cover, normalized difference vegetation index, cumulative sand thickness and elevation. The integration of multiple thematic layers was accomplished using the overlay weighted method to generate a potential groundwater zonation map and the accuracy of the resulting map was validated against a groundwater resource potential map. Statistical measures demonstrate an 82% agreement between the two maps, indicating a high level of concurrence. Accordingly, three groundwater zones of good, average and bad potential have been identified in the study area. In the current study, a process that combines weighted ranking with spatial data transformation and harmonization has been developed to obtain information for accurate decision-making. The results accruing from this research have significant ramifications for creating regional sustainable groundwater management plans. [ABSTRACT FROM AUTHOR]

This paper examines the impact of a change in the policy regime from flat rate to free farm electricity pricing, introduced in Punjab, India in February 1997 using a difference‐in‐differences framework. Based on village‐level data from the second and the third rounds of the Minor Irrigation Census, the study finds a differential increase in the number of electric‐operated tubewells and horsepower load of pumps in Punjab as compared to an agriculturally‐similar and neighboring state, Haryana, which is taken as the control group. Through these channels, the study finds that the average groundwater depth increased by 1.9 meters more in Punjab as compared to Haryana, which is 22 percent of the baseline average groundwater depth in Punjab. Nationally‐representative well‐level data on groundwater depths from the Central Ground Water Board shows impact heterogeneity with sharper effect on groundwater depth for wells that are lying closer to the cut‐off of about 10 meters where a technological shift from centrifugal to submersible pumps is required to maintain access to groundwater pumping. [ABSTRACT FROM AUTHOR]

An arid climate accompanied by a freshwater shortage plagued Egypt. It has resorted to groundwater reserves to meet the increasing water demands. Fossil aquifers were lately adopted as the sole water source to provide the irrigation water requirements of the ongoing reclamation activities in barren areas. Yet, the scarcity of measurements regarding the changes in the aquifers' storage poses a great challenge to such sustainable resource management. In this context, the Gravity Recovery and Climate Experiment (GRACE) mission enables a novel consistent approach to deriving aquifers' storage changes. In this study, the GRACE monthly solutions during the period 2003–2021 were utilized to estimate alterations in terrestrial water storage (TWS) throughout Egypt. Changes in groundwater storage (GWS) were inferred by subtracting soil water content, derived from the GLDAS-NOAH hydrological model, from the retrieved TWS. The secular trends in TWS and GWS were obtained using the linear least square method, while the non-parametric technique (Mann–Kendall's tau) was applied to check the trend significance. The derived changes in GWS showed that all aquifers are undergoing a significant loss rate in their storage. The average depletion rate over the Sinai Peninsula was estimated at 0.64 ± 0.03 cm/year, while the depletion rate over the Nile delta aquifer was 0.32 ± 0.03 cm/year. During the investigated period (2003–2021), the extracted groundwater quantity from the Nubian aquifer in the Western Desert is estimated at nearly 7.25 km3. The storage loss from the Moghra aquifer has significantly increased from 32 Mm3/year (2003–2009) to 262 Mm3/year (2015–2021). This reflects the aquifer exposure for extensive water pumping to irrigate newly cultivated lands. The derived findings on the aquifers' storage losses provide a vital source of information for the decision-makers to be employed for short- and long-term groundwater management. [ABSTRACT FROM AUTHOR]

The need for freshwater supplies is increasingly rising according to the increase in the inhabitants' expansion and economic growth. Available water resources are reduced by pollution and overpumping. This research's prime objective is to study changes in the water quality of the Pleistocene aquifer in Minia Governorate. Historical hydro-chemical data of the groundwater in two years 2009 and 2019 were used to study the changes in the groundwater quality of the Pleistocene aquifer under the impact of the recharge and discharge processes. The Nile River, and the Al-Ibrahimia and Bahr Youssef Canals are considered the main sources of aquifer recharge. Collected data from 53 groundwater wells in the Pleistocene aquifer were used to calculate the sodium adsorption ratio (SAR), sodium percentage (Na%), Kelly index (KI), Soluble Sodium Percentage (SSP), magnesium ratio (MR%), permeability index (PI) and chloro-alkaline index (CAI). These data were used to evaluate and detect the quality and changes in groundwater through the years 2009 and 2019 using spatial mapping in the geographic information system (GIS). The values of SAR, KI and Na% varied between 0.06–1.22, 0.02–0.57 meq/L and 3.7–37.63%, respectively, in the year 2009, but these values changed to 0.4–0.75, 0.16–0.28 meq/L and 15.07–23.44% in the year 2019. The calculated MR and PI values indicate that 100% of the groundwater samples were in the "suitable" category. The calculated SSP reflects no changes in groundwater alkalinity between the years 2009 and 2019. The hydro-chemical analysis of the studied groundwater (G.W.) samples shows high pollution levels caused by Pb and Fe in some parts of the study area. Pb was found to be >40 µg/L in the middle parts, whereas Fe was found with high levels in 27% of the studied groundwater samples. The localities of these samples were affected by pollution from the industrial wastewater from the sugar factory of Abou-Qarqas city (e.g., El-Moheet drain), the fertilizer leaching process and pesticides seeping into groundwater from soils and agricultural wastewater. [ABSTRACT FROM AUTHOR]

The paper presents a current example of sprinkler irrigation at "ASG", made using water from the CPE drainage channel, from the Cena area, Timiș County. In Banat, the water source for irrigation from the Timis and Bega Rivers is limited during the period of summer when it is necessary to apply irrigation in the area where there is no other source of water available, which is why it is necessary to find new sources of water available even for local facilities, such as: groundwater, sess accumulations, ponds, water from desiccation etc. [ABSTRACT FROM AUTHOR]

In recent years, climate change has caused extreme weather all over the world, including in Taiwan. Rainfall in Taiwan is distributed unevenly in both time and space, leading to a shortage of water resources which has become a pressing issue for the island. Groundwater plays a vital role as a backup and supplementary water resource. This study proposes a method that combines the seepage theorem, field observations, and a numerical simulation to identify high-potential groundwater resource regions to meet the demand for water supplies in future development. The Taichung Chingshui Coastal Plain (TCCP) was selected as a study area for testing the method. Two new wells were drilled in the area to obtain additional information to supplement the analysis of groundwater levels (GLs). Results indicate that the hydrological and hydrogeological parameters (e.g., Manning's coefficients, hydraulic conductivity, and formation thickness) can be obtained reasonably by comparing the numerical simulation with the observed GLs. It was found that the Dadu, Waipu, and Qingshui districts are the top three areas with higher potential groundwater resources in the TCCP. Data from the observations wells and in situ pumping stations verified our simulation results, which showed that our proposed methodology is advantageous. The research results can help improve the effective use of existing groundwater resources and assist with water resource development and sustainable usage. [ABSTRACT FROM AUTHOR]

The aim of this research is to develop a GIS-based simulation for selecting the most suitable site of solid waste landfill which could help to minimize harmful impacts to the environment and society in the extreme sensitive and complex delta by an integration of geographic information system (GIS) and analysis hierarchy process (AHP) and nine criteria (distance from surface water; depth of ground water table; distance from residential area, land use, distance from main roads, geo-environmental and geotechnical characteristics, distance from historical and tourism sites, and distance from industrial zones). Different from most of the previous studies on the landfill site selection, geology-related criteria including soil types/lithology, soil permeability, and soil depth/soil thickness (soil-structure), which are called geo-environmental and geotechnical characteristics in this research, will be carefully considered, integrated, and evaluated. The AHP was employed to determine the weight of each criterion based on pair weight comparison and its matrix, while a land suitability index (LSI) score was calculated to determine the most suitable site. Moreover, the suitability map was also created which indicated very advantageous, advantageous, rather advantageous, and disadvantageous areas in the study area for landfill siting. Finally, the developed model could be used for supporting planners, managers, policy makers, and local government to make decisions on suitable and effective planning strategies for landfill site selection and could be applied anywhere and especially in other deltas around the world. [ABSTRACT FROM AUTHOR]

We report the isotopic composition of the surface water and groundwater of the Kosi River fan on the Himalayan Foreland, India. We have collected 65 water samples from surface water (Kosi River (n = 2), streams (n = 9), waterlogging (n = 29), and canal (n = 4)), and groundwater (n = 21) for δ18O and δ2H analysis during December 2019. We obtained groundwater level data measured at the observation wells from the Central Groundwater Board, India, for 1996 and 2017. The groundwater level varies from 1.0 to 8.1 m below ground level (bgl) and from 0.5 to 9.0 m bgl during 1996 and 2017, respectively. We have used water table fluctuation approach to estimate the recharge rate. The recharge rate in the Kosi Fan varies from 0.7 to 21.4 mm/year from 1996 to 2017. Further, we have used δ18O and δ2H values of water samples to identify the source and the interaction between surface water and groundwater. The δ18O value of groundwater shows a wide variation (from −9.3‰ to −5.6‰) compared to the surface water, i.e., streams (−7.8‰ to −6.4‰) and canals (−6.9‰ to −6.0‰), suggesting mixing in groundwater during recharge processes. Furthermore, we have used a two-component mixing model to assess the fraction contribution from streams and precipitation to groundwater. The estimated fraction contribution from stream water to groundwater ranges from 45 to 83%. We also suggest higher recharge is limited up to the depth of 6 m bgl. We suggest precipitation and surface water actively recharge groundwater. We conclude that marked spatial variation in the isotopic composition of groundwater is mainly due to the local recharge sources and interaction between surface water and groundwater. [ABSTRACT FROM AUTHOR]

Aquifers are ubiquitous, and their water is easy to obtain with low extraction costs. On many occasions, these characteristics lead to overexploitation due to important water level declines, reduction of river base flows, enhanced seawater intrusion, and wetland affection. The forecasted increase in water demands and global warming will impact the future availability of water resources. Conjunctive use of surface and subsurface waters can help in mitigating these impacts. There are two main conjunctive use strategies: artificial recharge (AR) and alternate conjunctive use (ACU). AR stores waters that are not to be used directly in aquifers. ACU utilizes groundwater in dry periods, while surface waters are preferred in wet ones; this allows the increase of water supply with lower dam storage, economic gains, and environmental advantages. Efficient conjunctive use can prevent soil salinization and waterlogging problems in semiarid countries due to excessive recharge from irrigation return flows or other origins. Groundwater is a neglected and generally misused resource to maintain environmental conditions. When considering the solution to a water resources problem, groundwater should always be part of the design as an alternative or a complementary resource. Aquifers have large inertia, and changes in their volumes are only noticeable after years of observations. Unfortunately, groundwater observation networks are much poorer than surface ones, something that should be changed if groundwater is to come to the rescue in these times of climate change. Human and material resources should be made available to monitor, control, analyze, and forecast groundwater. [ABSTRACT FROM AUTHOR]

Extensive use of groundwater in the rice–wheat cropping system of northwest India has resulted in groundwater depletion at an alarming rate of 33–88 cm per year over the past 2–3 decades. Projected climate change is likely to affect crop water demand, groundwater withdrawal, and replenishment in future. A modeling study was undertaken to simulate the impact of climate change on groundwater resources under existing rice–wheat cropping system and with revised crop management strategies in the Karnal district of Northwest India. Different cop management strategies considered are marginal shift in sowing dates of rice and wheat, and fractional diversification of rice area to maize. MODFLOW software driven by the projected climate change scenarios under four representative concentration pathways (RCP2.6, RCP4.5, RCP6.0, and RCP8.5) were used for simulating groundwater behavior in the study area under business as usual and proposed crop management strategies. Simulation results indicated 4.3–61.5 m (28.9–291.2%) additional decline in groundwater levels in different zones of the study area under different RCPs by the end century (2070–2099) period in relation to the reference groundwater level of year 2015 under the existing sowing dates of 15 June for rice and 15 November for wheat. Maintaining rice sowing date at 15 June but advancing wheat sowing date by 10 days can reduce groundwater decline by 9.8–14.4%, 14.4–19.6%, and 18.1–25.8% under different RCPs by the end of early (2010–2039), mid (2040–2069), and end (2070–2099) century periods, respectively, vis-à-vis prevailing sowing dates. Replacing 20%, 30%, and 40% rice area with maize in rice–wheat system is likely to reduce groundwater decline by 7.1 (24.9%), 10.1 (35.3%), and 13.8 m (48.5%), respectively, in comparison to projected end century (2099) decline of 28.5 m under the prevailing sowing dates of rice–wheat. However, declining groundwater trend of rice–wheat would be reversed with the replacement of 80% rice area under maize crop. Simulation results suggest that specific crop management strategies can potentially moderate groundwater decline in the study area under the envisaged climate change. [ABSTRACT FROM AUTHOR]

This study concerns the development of a methodology using modern techniques of data generation (Modeling) and interpretation (GIS) to compute groundwater plausibly at regional scale, alternate to previously established norms. The approach is centered on quantitative estimation of two main parameters-input and output. GIS techniques along with soil vegetation model (CropSyst) have been demonstrated for the calculation of groundwater balance components. Using the developed methodology water resources of the Ludhiana district for the period between, 2000 and 2010 were estimated. The temporal changes in water balance components indicated that the major inputs to the hydrologic system are rainfall and canal water and the major out component are evapotranspiration (ET). Multi-annual (2000 to 2010) average of 719 mm rainfall, 88 mm canal water, 74 mm of groundwater inflow, with annual loss 974 mm as ET, caused 123 mm of net negative groundwater recharge in Ludhiana district. The annual computed rise/fall with the developed methodology closely matched the observed values. [ABSTRACT FROM AUTHOR]

The depletion of groundwater resources in Northwest India has been extensively studied. The top priority to meet the scarcity of water for irrigation, industrial and domestic purposes is supplemented by groundwater. Geostatistical modelling approach is considered to be beneficial tool for the assessment, evaluation, monitoring, and management of groundwater resources. This study is an attempt to analyze the spatio-temporal variability of groundwater level in semi-arid region of Panipat district, Haryana, India using kriging technique to fill the data gaps. Ordinary kriging was found optimal for the interpolation of groundwater levels. The results revealed that there was not much seasonal variation and also the groundwater flow direction remained almost constant in the study area during the assessment period. Spatial variability analysis showed significant variation in groundwater level and further depicted that the study area had undergone more or less decline in groundwater over the period of time. To validate the observations and results geo spatial and remote sensing techniques including normalised difference vegetation index and impervious surface relationships were worked out. It was further co-related with the rainfall data and the canal network existing in Panipat region. The integrated approach substantiated the observed results with the ground reality and helped in better understanding of the causes of declining groundwater trend in central part of Panipat. [ABSTRACT FROM AUTHOR]

The Ca Mau peninsula (CMP) is a key economic region in southern Vietnam. In recent decades, the high demand for water has increased the exploitation of groundwater, thus lowering the groundwater level and leading to risks of degradation, depletion, and land subsidence, as well as salinity intrusion in the groundwater of the whole Mekong Delta region. By using a finite element groundwater model with boundary expansion to the sea, we updated the latest data on hydrogeological profiles, groundwater levels, and exploitation. The basic model setup covers seven aquifers and seven aquitards. It is determined that the inflow along the coastline to the mainland is 39% of the total inflow. The exploitation of the study area in 2019 was 567,364 m3/day. The most exploited aquifers are the upper-middle Pleistocene (qp2–3) and the middle Pliocene (n22), accounting for 63.7% and 24.6%, respectively; the least exploited aquifers are the upper Pleistocene and the upper Miocene, accounting for 0.35% and 0.02%, respectively. In the deeper aquifers, qp2–3 and n22, the change in storage is negative due to the high exploitation rate, leading to a decline in the reserves of these aquifers. These groundwater model results are the calculations of groundwater reserves from the coast to the mainland in the entire system of aquifers in the CMP. This makes groundwater decision managers, stakeholders, and others more efficient in sustainable water resources planning in the CMP and Mekong Delta (MKD). [ABSTRACT FROM AUTHOR]

In marginal and central alluvial plains (Ganga Plain) of India, the inland salinity is continuously increasing, canal network and arid to semi-arid climatic conditions that led to excessive evapotranspiration concentrates the salt in soil and thereby escalating the groundwater salinity. In Mat Tahsil, Mathura district (Ganga Plain) study on shallow and deep aquifer salinity and fluoride was carried out in August 2001 and 2004. Groundwater salinity in some parts is more then 4000μΩ−1/cm. This region is severely affected by endemic fluorosis due to consumption of fluoride-contaminated water. Analysis of F−, Na+, K+, Cl− and HCO3 − was carried out at 30 sites of dugwells and borewells. Result shows that there is a variation and continuous escalation in the groundwater salinity and fluoride concentration in deep and shallow aquifers on the basis of analysis. Classification of salinity levels was carried out in 2001 and 2004. The deep aquifers (borewells) are found more saline as compare to the shallow aquifers (dugwells) while F−, Na+, K+, Cl− and HCO3 − shows high concentration in shallow aquifers. The fluoride concentration in the groundwater of these villages showed values from 0.1 to 2.5mg/l, severe enough to cause dental and skeletal fluorosis among the inhabitants, especially children of these villages. One of the major effects of inland salinity in this region is from saline groundwater, which is reaching the land surface and causing soil salinisations and water logging in the NE and SE parts of Mat block. [Copyright &y& Elsevier]

The Chennai aquifer system, which occupies an area of 6629 km2, is one of the most stressed aquifer systems in southern India and is under severe threat of over exploitation and quality deterioration. This is due to the increasing groundwater abstraction for irrigation, domestic, industrial purposes and for drinking water supply to the ever-expanding Chennai city. To offset the effect of this heavy extraction a paradigm shift towards groundwater management was imperative. A multidisciplinary integrated approach was used to map the aquifers, delineate their geometry, to determine the hydraulic behavior of the aquifer system, and to formulate an aquifer management plan through the development of a groundwater flow model. The main aquifers in the area include weathered and fractured crystalline rocks and recent alluvial formation. Alluvium is the most significant aquifer system in the study area, and this aquifer contains potable quality groundwater except in the eastern part of the study area that has been affected by seawater intrusion. A two-layered groundwater flow model was developed using Visual MODFLOW classic version 4.6 with a 1 km2 grid pattern to simulate groundwater flow for a period of 9 years. The model was calibrated under steady and transient state conditions and allowed components of the water balance of the system to be determined at a regional scale. The simulated results indicate that this aquifer system is under tremendous stress at the prevailing groundwater withdrawal rate of 899 million cubic meter (mcm)/year and would become unstable with the predicted 25% increase in groundwater withdrawal by 2025. However, the interventions to recharge an additional 54 mcm of water could help mitigate the current decline in potentiometric heads and could partially help to arrest the further advancement of seawater intrusion. A scenario of maintaining flow in rivers for a period of 120 days each year coupled with the construction of an unlined canal shows increase in groundwater head and development of the groundwater mounds, which are positive signs for arresting the decline of the water table and pushing saline groundwater in a seaward direction. As a result of the high rate of groundwater depletion in the area, management strategies need to be implemented urgently in the region. These strategies should include the regulation of groundwater abstraction and maintaining an extended flow period in the rivers. These measures are required to improve the sustainability of the available groundwater resources of the region. [ABSTRACT FROM AUTHOR]

The article argues that the recently introduced model for the direct delivery of an energy subsidy to well-irrigators in Indian Punjab aimed at incentivizing them to conserve electricity and groundwater is on a weak conceptual footing. Energy quota based on connected load will only lead to the resource-rich appropriating the subsidy benefits. Reduced use of well water to irrigate paddy will not arrest depletion as a large proportion of that water returns to the aquifer. The article suggests some institutional alternatives for bringing about long-term changes in the groundwater balance of Punjab based on sound water-use hydrology and the use of technology and market forces. [ABSTRACT FROM AUTHOR]

The economy continues to grow in Taiwan, and water demand from both households and industry has also continued to increase, which has led to water scarcity problems rising throughout the island. Thus, groundwater plays an essential role as a backup to supplement water resources. Considering that overpumping might lead to groundwater depletion, land subsidence, and even water quality issues, drawing up a more efficient strategy for groundwater management is necessary. This study proposes a dynamic adjusting pumping rate based on the exceedance probability of the historical groundwater table and the regional sensitivity of the pumping rate. The sensitivity of regional groundwater depletion was calculated by solving a Jacobian matrix composed of various pumping scenarios from numerical simulations. The coastal region of the Taichung City of Taiwan was selected as the study site to test our method. The result indicated that the groundwater table drawdown affected by pumping was reduced from 3.0 to 0.17 m in the 2015 dry season. During the period, groundwater of approximately 750,000 t was provided. Similarly, 350,000 t of groundwater resources and only a 0.09 m drawdown were accomplished in the 2016 wet season. Thus, this study proposed a groundwater dynamic management rule based on the current water level that effectively improves the efficiency of using groundwater resources. [ABSTRACT FROM AUTHOR]

Groundwater is the largest available reservoir of freshwater. But the rapid increase in the population and urbanisation, has led to over exploitation of groundwater which imposed tremendous pressure on global groundwater resources. Because of the hidden and dynamic nature of groundwater, it requires appropriate quantification for the formulation of groundwater planning and management strategies. The present study evaluates the efficacy of geospatial technology based Multi Influence Factor (MIF), Weight of Evidence (WofE) and Frequency Ratio (FR) technique to evaluate groundwater potential using a case study of basaltic terrain. The thematic layers influencing the groundwater occurrence viz. rainfall, slope, geomorphology, soil type, land use, drainage density, lineament density, and elevation were prepared using satellite images, hydrologic, hydrogeologic and relevant field data. Based on the conceptual frameworks of MIF, WofE and FR techniques these thematic layers and their features were assigned with appropriate weight and then integrated in the ArcGIS platform for the generation of aggregated raster layer which portray the groundwater potential zones. The results of validation showed that the groundwater potential delineated using MIF technique has a prediction accuracy of 81.94%, followed by WofE technique (76.19%) and FR techniques (71.43%). It is concluded that for evaluation of groundwater potential, the MIF technique is most reliable, followed by the WofE technique. The evaluated groundwater potential zones are useful as a scientific guide to identify the suitable location of wells and recharge structure in a cost-efficient way and also for the development of structured and pragmatic groundwater management strategies. [ABSTRACT FROM AUTHOR]

Canal seepage losses can contribute significantly to groundwater aquifers in arid and semi‐arid regions worldwide. In addition, surface water evaporation and evapotranspiration from adjacent riparian vegetation directly affect surface water availability across these regions. This study aims to evaluate interactions between irrigation canals and the Nile Delta groundwater aquifer in Egypt under four operational scenarios: (i) decreased stream flows in the four main diversion canals associated with upper Nile diversions and climate change, (ii) concrete lining of irrigation canals, (iii) combined lining and use of Photo‐Voltaic (PV) Solar Panel covers on canals and (iv) enclosure of the canals in closed conduits. We investigated the effects of these scenarios on regional groundwater supplies and levels using MODFLOW and water budget analyses. Decreased streamflow (scenario 1) resulted in decreased aquifer recharge (from 732 910 to 483 800 m3 day−1) and lower groundwater levels as compared to the base case (present) conditions. Moreover, groundwater flows from the aquifer to the four main canals noticeably increased from 23 176 to 79 364 m3 day−1. Water budget analyses associated with canal lining scenarios (2, 3, & 4) indicated that canal leakage to the aquifer accounted for 146 582, 146 582, and 73 291 m3 day−1 respectively. The changes in canal efficiencies reached 29.3%, 67.1%, 75.3%, and 91.8% while the changes in aquifer recharge efficiencies were 66%, 20%, 20%, and 10% for the four scenarios, respectively. Overall, we found that canals lining is likely the most suitable solution for managing water resources in the Nile Delta. Further aspects to be considered in future studies include the loss of biodiversity along streams embankments due to channel lining. [ABSTRACT FROM AUTHOR]