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With the gradual improvement in coal mining efficiency, the disturbance of groundwater systems caused by high-intensity mining also increases, leading to challenges in maintaining mine safety and protecting water resources in mining areas. How to accurately describe the dynamic changes in the groundwater system under mining and quantitatively predict mine water inflow are currently major problems to be addressed. Based on a full analysis of the response characteristics of a groundwater system to the extraction disturbance, this paper presents a new method to establish a mine hydrogeological conceptual model that can accurately represent the water inrush process. The unstructured-grid package of MODFLOW is used to accurately characterize the formation structure and finally make accurate water inflow predictions. Taking the Caojiatan coal mine in Shaanxi Province, China, as an example, a numerical model of unstructured water inflow is established, and the changes in the water inflow source and intensity are quantitatively evaluated. Compared with the traditional water inflow prediction method, the prediction accuracy of the new model is improved by 12–17%, which is achieved by detailing the response of the complex groundwater system under high-intensity mining conditions. The method presented in this paper has great significance and applicatory value for obtaining a comprehensive understanding of the disturbance characteristics of human underground engineering activities (e.g., coal mining) on groundwater systems, as well as accurately predicting water inflow. [ABSTRACT FROM AUTHOR]

Currently, the demand for water is rising, and as a result, the groundwater is declining. Water supplies are not sufficient for agricultural productivity, environmental preservation, or ecosystem services, resulting in an unbalanced water budget in the basin. The goal of this paper is to assess the groundwater recharge in the Jedeb sub-basin using WetSpass-MODFLOW coupling. A spatially distributed water balance model is developed to simulate long-term average recharge depending on land cover, soil texture, topography, and hydro meteorological parameters. The groundwater model is iteratively connected to the recharge model in order to simulate recharge. This means that the depth of the groundwater affects the recharge estimate and vice versa. The average yearly evapotranspiration, surface runoff, and groundwater recharge were determined using WetSpass-M to be 574, 898, and 99 mm, respectively. Groundwater recharge accounted for 6.3% of precipitation, while actual evapotranspiration and surface runoff accounted for 36.4% and 57% of precipitation, respectively. In such seasonal variations, the groundwater level in the Jedeb Sub-basin was studied under various stress conditions (dry season, wet season, and annually). The groundwater level distribution varied from 2,052.3 to 3,063.06 m in the summer stress period (recharge). While in the winter stress period (recharge), the groundwater level varied from 2,051.41 to 3,061.92 m, and the groundwater level due to the annual stress period (recharge) varied from 2,053.76 to 3,064.5 m. With a correlation coefficient of.89, which is an acceptable fit between the simulated and observed heads in steady state for all stress periods (summer, winter, and annual recharge). The contribution of this study could be used as baseline information for regional water resource experts, policymakers, and researchers for further investigation. [ABSTRACT FROM AUTHOR]

This paper investigates the optimal remediation process in an aquifer using Modflow 6 software and genetic algorithms. A theoretical confined aquifer has been polluted over a long period of time by unnoticed leakage in a pipeline conveying leachate from an adjacent landfill to a wastewater treatment plant. When the extended leakage and groundwater pollution are discovered, the optimal planning of the remediation strategy is investigated using the pump-and-treat method or/and hydrodynamic control of the pollution. The practical goal is to find the optimal locations and flow rates of two additional pumping wells, which will pump the polluted water or/and control pollution, protecting an existing drinking water pumping well, securing its fully operational mode even during the remediation process with the minimum possible cost, simply represented by the pumped water volume of the additional wells. The remediation process is considered complete when the maximum concentration in the aquifer drops below a certain limit. The Modflow software (handled by the Flopy Python package) simulates the flow field and advective–dispersive mass transport, and a genetic algorithm is used as the optimization tool. The coupled simulation–optimization model, Modflow-GA, complemented by a sophisticated post-processing results analysis, provides optimal and alternate sub-optimal remediation strategies for the decision makers to select from. [ABSTRACT FROM AUTHOR]

The paper investigates the mechanism of seawater intrusion and the performance of free and open-source codes for the simulation of variable density flow problems in coastal aquifers. For this purpose, the research focused on the Marathon Watershed, located in the northeastern tip of Attica, Greece. For the simulation of the groundwater system, MODFLOW, MT3DMS and SEAWAT codes were implemented, while sensitivity analysis and calibration processes were carried out with UCODE. Hydraulic head calibration was performed on the MODFLOW model, and TDS concentration was validated in the SEAWAT model. The calibrated parameters of the MODFLOW model were obtained for the variable density flow simulation with SEAWAT. The MODFLOW and SEAWAT hydraulic head outputs were analyzed and compared to one another. The outcome of this analysis is that SEAWAT produced slightly better results in terms of the hydraulic heads, concluding that parameter transferability can take place between the two models. For the purpose of the seawater intrusion assessment, the use of the SEAWAT code revealed that the aquifer is subjected to passive and passive–active seawater intrusion during wet and dry seasons, respectively. Finally, an irregular shape of a saltwater wedge is developed at a specific area associated with the hydraulic parameters of the aquifer. [ABSTRACT FROM AUTHOR]

Groundwater level (GWL) refers to the depth of the water table or the level of water below the Earth's surface in underground formations. It is an important factor in managing and sustaining the groundwater resources that are used for drinking water, irrigation, and other purposes. Groundwater level prediction is a critical aspect of water resource management and requires accurate and efficient modelling techniques. This study reviews the most commonly used conventional numerical, machine learning, and deep learning models for predicting GWL. Significant advancements have been made in terms of prediction efficiency over the last two decades. However, while researchers have primarily focused on predicting monthly, weekly, daily, and hourly GWL, water managers and strategists require multi-year GWL simulations to take effective steps towards ensuring the sustainable supply of groundwater. In this paper, we consider a collection of state-of-the-art theories to develop and design a novel methodology and improve modelling efficiency in this field of evaluation. We examined 109 research articles published from 2008 to 2022 that investigated different modelling techniques. Finally, we concluded that machine learning and deep learning approaches are efficient for modelling GWL. Moreover, we provide possible future research directions and recommendations to enhance the accuracy of GWL prediction models and improve relevant understanding. [ABSTRACT FROM AUTHOR]

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Aquifer systems, because of the presence of frequently complex geological structures, may extend beyond watersheds limits. Interbasin groundwater flow is often identified among watersheds. Because geological systems are complex ones, modelling tools are needed for its estimation. In this paper, we quantify the outflows from the endhoreic Gallocanta watershed (Spain) by means of a MODFLOW numerical model in order to assess the robustness of the boundaries of the Gallocanta Groundwater Body. Our results show the Gallocanta watershed is hydrogeologically connected with the adjoining Piedra-Ortiz and Jiloca watersheds (discharging annually in these basins about 4 and 1 Mm3 respectively). Furthermore, we hypothesized the presence of geological features altering the groundwater flow. Additional simulations were run to analyse the changes in the water budget in the cases of: i) groundwater pumping no longer allowed by the authorities, and ii) a potential drought scenario. In the first case, the results forecast an increase in discharge to the Piedra-Ortiz and Jiloca watersheds, while in the second case a diminution of the outflows to the two neighboring basins is foreseen. We then propose a larger and unique groundwater body, spanning from the Caminreal Springs on the east and the Piedra-Ortiz basin on the west, including a moving groundwater divide internal to the Gallocanta watershed. Monitoring the baseflow of the Piedra-Ortiz river and of the Caminreal Springs will allow to get information on the evolution of the groundwater resource availability in the Gallocanta watershed. Our results stress the importance of conjunctively using data and traditional geologic knowledge (i.e. surface geology maps) along with numerical modelling analyses. This holds especially true in areas, such those of hard-rock aquifers, where scarce hydrogeologic data are available, to test conceptual models, to derive and to infer information on water budgets and on the presence of relevant structural features driving the groundwater flow. This approach may lead to informed decision-making on groundwater body boundaries definition for the application of relevant groundwater management regulations. [ABSTRACT FROM AUTHOR]

This paper focuses on deriving new approximate analytical solutions in wedge‐shaped aquifers. The proposed methodology is applicable to any type of aquifer namely, leaky, confined and unconfined, under both steady state and transient flow conditions. By applying the method of images and separating the flow field into sections using physical arguments, approximate analytical expressions are obtained for the drawdown function, which in contrast to the conventional theory, are applicable to any arbitrary wedge angle. Moreover, the solutions fully observe the boundary conditions, while they preserve the continuity of the drawdown, which can be calculated directly at any point of the flow field. Nevertheless, comparison of the results of the new approximate analytical solutions to numerical ones, has been considered necessary to check their validity. MODFLOW, a well‐known numerical tool is used to calculate the numerical results. The discrepancies between the numerical results and those of the approximate analytical solution are negligible. The main advantages of the proposed methodology are the following: (a) The model needs only finite number of terms compared to conventional analytical and numerical solutions that involve infinite series, (b) The computational load is low, so it can be easily used in conjunction with meta‐heuristic algorithms to solve groundwater resources optimization problems, (c) Stream depletion rate can be calculated rather accurately and (d) The method is applicable to related flow problems. Key Points: New functions for drawdown calculation in wedge‐shaped aquifers are presentedThe proposed functions are suitable to be used in conjuction with meta‐heuristic algorithms to solve groundwater optimization problemsConvergence of the results obtained from the set of functions and numerical methods (MODFLOW) point out the validity of the proposed solutions [ABSTRACT FROM AUTHOR]

The groundwater modelling tool is an important structural tool for solving many groundwater-related problems. Visual-MODFLOW is one of such tool that uses finite-difference (FD) method to unravel the problems. In this paper, Visual-MODFLOW 2000 has been utilized for analysing the groundwater-level simulation in Purba (East) Midnapur, West Bengal, India. The data of pumping well discharge have been collected at two different time periods 2002 and 2012. The simulated pumping well records for 2012 based on the pumping well discharges measured in 2002 and the observed records in 2012 have been critically examined, compared, and correlation coefficients are found out to signify data validity. Also simulated groundwater-level data of 2019 to 2023 based on well discharge records in 2002 and 2012 have also been correlated for its justification. This paper concluded that the groundwater flow occurs from south to north direction of East Midnapur, as the saline water intrusion from the nearby sea takes place into the aquifers towards inland direction. It confirms a good agreement with future simulation data. In the real field situation, saline water encroachments have affected the aquifers and it has covered up to 50 km of location from Kalindi (near seashore) to Nandakumar (inland) location. This paper focuses on the groundwater-level forecasting in prospective groundwater managing scenarios in the region concern. [ABSTRACT FROM AUTHOR]

The multi-aquifer system of the Nubian aquifer in central Sudan hydrogeological system was simulated using a three-dimensional steady-state model. The goal of the study is to detect the effect of pumping on the groundwater flow and thus, the aquifer productivity. The conceptual model of the study area was built based on the available geological and hydrogeological data guided by geophysical survey. Processing MODFLOW numerical code was used to calculate the hydraulic head and water balance under the existing boundary conditions. The model accurately simulated the hydraulic head with a determination coefficient of 0.88. The calibrated model indicated that the change in storage is 0.56 m3/day indicating the study area constitutes highly productive zone and is recommended for groundwater developments. [ABSTRACT FROM AUTHOR]

Agricultural intensification has boosted land productivity, but it has also created new sustainability issues. As one of the most important human habitations and agricultural farming areas in arid areas, the Cele Oasis has a very developed agricultural system. This paper studies the long-term effects of different types of agricultural intensification strategies on groundwater level fluctuations in the Cele Oasis. A soil water flow (HYDRUS-1D) and aquifer simulation (MODFLOW) coupling model were used to construct the geometric structures of the vadose zone and saturated zone in the Cele Oasis and to analyze the recharge and discharge mechanism of the oasis. The results showed that HYDRUS-1D accurately simulated soil moisture transport in the Cele Oasis, providing reliable data for calibration of the MODFLOW model. The groundwater level simulated by MODFLOW was in good agreement with the observed value. The results of the R2, RMSE, and NSE were ranges of 0.77–0.90, 0.45–0.74 m, and 0.76–0.87, respectively. The errors were acceptable limits. The coupling model predicted the responses of different agricultural types and cropping scenarios to groundwater. Predictions showed that the groundwater level in the Cele Oasis remained stable under the current cropping scenario (100% cropping intensity), and that the groundwater level decreased slightly under the cropping scenario (110% cropping intensity and 130% cropping intensity). When the cropping scenario was at 170% cropping intensity, the groundwater level decreased rapidly, and the maximum drawdown value was 7 m. Therefore, the maximum cropping intensity of the Cele Oasis in the future should be 130% of the current cropping intensity. [ABSTRACT FROM AUTHOR]

This paper constitutes an assessment of the climate change (CC) impacts on the Zeuss–Koutine (ZK) aquifer in southeastern Tunisia using a WEAP-MODFLOW decision support system (DSS). Efficiency criteria are calculated for hydraulic heads to validate the MODFLOW model. The DSS simulates the behavior of the aquifer while representing demands and other water sources. It is able to evaluate monthly water management scenarios up to 2030. It emphasizes the seriousness of the water resource situation in the region exhausted by the increasing demands and the climate circumstances which leads to the risk of salinization. The DSS shows a calculated aquifer drawdown during the simulation period (1982–2010) of 22.0 m which is exactly the recorded one. To simulate future CC, data are collected from the "Climate Wizard" web site, providing results of 16 general circulation climate models under A2, A1B, and B1 emission scenarios. Based on precipitation changes, three scenarios are deduced: the mean, the worst, and the best CC. Results show that the forecasted average drawdown (2010–2030) would be between 30.5 (1.5 m/year) and 33.9 m (1.7 m/year) under the best and the worst CC scenarios, respectively. The worst CC scenario could lead to the intrusion of brackish lagoon water or even a long-term marine intrusion. The use of the Jerba Sea Water Desalinization Plant (JSWDP), in 2018, would improve the situation, and the average estimated drawdown would be 16.9 m (0.8 m/year) under the mean CC, presenting then an improvement of about 49%. The ZK aquifer would lose 121% of its storage under the coupled JSWDP_mean CC scenario, between 1982 and 2030, presenting an improvement of about 52% compared to CC scenarios. [ABSTRACT FROM AUTHOR]

Objective Hetao Irrigation District relies on Yellow River water for irrigation, but excessive use of the river water had resulted in soil salinity. Jointly using groundwater and river water has been postulated as a feasible mitigation technology, and the purpose of this paper is to present the results of a study on how to achieve optimal use of groundwater and surface water. Method A three-dimensional groundwater model for the region was calibrated and verified using MODFLOW based on measured groundwater depths and other datasets. We then applied the model to four typical well-canal combination areas in four sub-districts: Wulanbuhe, Jiefangzha, Yongji and Yichang. 44 scenarios with four different well-irrigation areas and 11 kinds of canal-well combination ratios were considered. For each scenario, we predicted how the groundwater depth changed with the well-canal combination ratio and well-irrigation area. Result The three-dimensional groundwater model correctly captured physical properties of the aquifers and soils and reproduced the observed change in groundwater depth at different scenarios. When the ratio of well-irrigated to canal- irrigated areas was the same, the average groundwater depth in Jiefangzha and Wulanbuhe was the shallowest followed by Yongji, with that in Yichang the deepest. Isograms of groundwater depth in areas with well-canal irrigation in Wulanbuhe was the densest, followed by Yichang, with Yongji and Jiefangzha the sparsest. When the well-irrigated area was constant, the average groundwater depth decreased asymptoticall as the canal-well combination ratio increased. Conclusion The suitable canal-well combination ratio and well-irrigation area for controlling groundwater depth not exceeding 3 m varied with the sub-districts due to their difference in hydrogeological conditions. The well-irrigation areas in Wulanbuhe, Jiefangzha, Yongji and Yichang should not exceed 12.25 km2, 12.25 km2, 9 km2 and 6.25 km2 respectively, with their associated ratio of canal-irrigated area to well- irrigation area not exceeding 2.5, 2.5, 3.0 and 3.3 respectively. [ABSTRACT FROM AUTHOR]

Climate change is one of the most significant issues facing humanity, and an increased number of countries are proactively addressing this problem. Any changes in water resources brought on by climate change would pose a serious risk to a lot of nations. Egypt is one of these nations which will suffer from climate change. One of the consequences of climate change is sea level rise (SLR), which in turn will lead to the advance of shore line in land and more seawater intrusion. The sea water will advance inland, flooding a significant portion of the good lands, and many inhabitants will leave their homes as a result. The Nile Delta is one of the most vulnerable areas to be inundated by sea water due to the flat topographical nature of the area. Moreover, a large part of the water in the Nile Delta aquifer (NDA) will become saline, and the reservoir will become more vulnerable to Seawater intrusion (SWI) Which is affected not only by the rise in sea level and the advance of shore line, but also by the excessive withdrawal from the pumping wells. In this paper (MODFLOW+SEAWAT+ARC GIS) were used to investigate seawater intrusion in Nile Delta aquifer and to determine the position of the new shore line due to 0.25 m and 0.5 m rise of the Mediterranean sea level in Nile Delta. Owing to the lack of data of the topography of the area, because it need high accuracy of Digital Elevation Model (DEM) the position of shore line is obtained based on analyzing the results of saltwater intrusion due to 0.25 m and 0.5 m of sea level rise of recent studies through SEAWAT and the results were exported to ARC GIS to get maps of new shore line. [ABSTRACT FROM AUTHOR]

Groundwater-dependent agricultural intensification has led to unsustainability of groundwater systems in many parts of the world. The unconfined aquifers in the Eastern Indo-Gangetic Plains (EIGP) of India are one of the most extensive aquifer systems in South Asia and are prone to ever intensifying agricultural systems. This paper aims at evaluating the long-term impacts of agricultural intensification on groundwater dynamics in an agriculturally important sub-region of EIGP. The study proposes a multi-model approach, combining the capabilities of vadose zone model (HYDRUS-1D) and aquifer simulation model (MODFLOW) to analyse the recharge and discharge mechanisms in the alluvial Gangetic Plains. The study mathematically reconstructed the vadose zone and aquifer geometry and implemented them into flow models. We demonstrate that the loosely coupled vadose zone and groundwater flow modelling framework is highly suitable for simulating the impact of changed cropping intensity on groundwater dynamics. The recharge estimates from HYDRUS-1D and calibration of regional groundwater flow model offered a robust set of parameter values for the prevalent conditions of EIGP. The results show good correspondence between the observed and simulated water table levels during calibration, with RMSE = 0.56–0.59 m, NSE = 0.76–0.99 and R2 = 0.83–0.91, all within acceptable limits. Projections showed that although the water table in the region would remain fairly stable under lower levels of cropping intensity (135–150%), further increase to 200 and 300% would lead to water table decline at the rate of 0.87 and 1.83 m per year, respectively. These changes could therefore impact future groundwater risk management in EIGP. This reinforces the view that groundwater-dependent intensification may be sustainable in long term only if adaptation strategies and compensatory measures are adopted. [ABSTRACT FROM AUTHOR]

Many shallow aquifers in north China are seriously polluted and cannot be used any more. Therefore, the confined groundwater exploitation is steadily increasing. With the rapid decline of confined groundwater head, the risk of confined aquifer contamination by leaky recharge from shallow aquifer is significantly increased. In this paper, the cumulated time that the pollutant concentration at the top of confined aquifer exceeds the highest allowable limit is defined as the confined aquifer vulnerability indicator. This process-based indicator is used to assess the confined aquifer vulnerability of Jining, China. In order to obtain confined aquifer vulnerability indicator, three-dimensional numerical simulation models of groundwater flow and solute transport are established by MODFLOW and MT3D respectively. Calibration and verification results, with correlation coefficient of 0.98 and 0.8, confirmed the reliability of numerical models which is then used to calculate the vulnerability indicator. Assessment results show that the confined aquifer in Shizhong District is the most vulnerable to pollutants and should be given more attention. As an alternative, the central and east part of the study area has the potential for exploitation. Further analysis reveals that both water head pressure difference and aquitard thickness have an important impact on the aquifer vulnerability. The vulnerability assessment map obtained by GIS shows the most vulnerable area is where the pollutant concentration increases most. Our proposed method provides the basis for confined groundwater environmental protection. [ABSTRACT FROM AUTHOR]

Nitrate contaminant degrades groundwater quality and threatens the health of the humans, livestock, and the environment. Damaneh-Daran aquifer is located at upstream of the Zayandehrood reservoir in west-central Iran. This aquifer has been highly contaminated by nitrate and is still rapidly being contaminated. Thus, its quality needs to be remediated. This paper is focused on the quantity-quality modeling to predict the average nitrate concentration of the aquifer. Several remediation scenarios are presented in a period beginning from fall 2019, ending in spring 2024. These scenarios address several ways to mitigate the injection of the major sources of contamination in the region, such as equipping the urban regions with wastewater collection and treatment plants and reducing the fertilizers' use. The decreased use of the fertilizers may be achieved through two strategies: directly reducing the amount of the fertilizers by several specific and predefined rates of reduction and indirectly decreasing the amount of the fertilizers used by crop pattern modification. The latter strategy is evaluated to replace all or a part of the areas allocated to the more fertilizer-demanding crops with those of the less fertilizer-demanding crops. Furthermore, some of these scenarios are hybridized to more mitigate groundwater quality degradation. The results of performing the proposed scenarios are once compared together and then compared with the trend scenario letting current case study conditions and facilities be held in the future. The results suggest that the scenario hybridizing the effects of the wastewater treatment plants-equipping scenario with those of the quality-enhancing crop pattern modification scenario is evaluated as the most effective and best-performing scenario, implementation of which offers 20% and 30% reduction of the nitrate concentration for the agricultural and urban areas, respectively. [ABSTRACT FROM AUTHOR]

High level of groundwater in urban areas may cause major problems in construction and mining projects. One effective solution is to implement drainage wells to lower the water table into the desired level through an appropriate pumping strategy. In this paper, placement and capacity of the dewatering wells are optimized by minimizing the total costs of a groundwater lowering system (GLS) through a simulation-optimization approach. For this purpose, MODFLOW, the groundwater simulation software, is coupled with the Firefly Optimization Algorithm (FOA) to find the optimal solution. The proposed FOA-MODFLOW model is tested in an urban area in east southern part of Iran, Kerman city's ancient Mosque region. Results show that the obtained cost-effective design noticeably outperforms the consulting engineers' proposal in terms of both the number of drilled wells and the associated costs with justifiable constraints. Optimal strategy satisfies the constraints by suggesting construction of two wells with totally pumping rate of 5503 m/day while the water table is dropped 1.5 m with a ground subsidence less than 80 mm in the region. Additionally, an investigation on the value of various design parameters emphasizes on the sensitivity of the solutions to the permissible groundwater level and the well's maximum pumping rates among the others. [ABSTRACT FROM AUTHOR]

In recent years, as a result of climate change as well as rainfall reduction in arid and semi‐arid regions, modelling qualitative and quantitative parameters belonging to aquifers has become crucially important. In Iran, as aquifers are treated as the most commonly used drinking water resources, modelling their qualitative and quantitative parameters is enormously important. In this paper, for the first time, values of salinity, total dissolved solids (TDS), groundwater level (GWL) and electrical conductivity (EC) of the Arak Plain, located in Markazi Province, Iran, are simulated by means of four modern artificial intelligence models including extreme learning machine (ELM), wavelet extreme learning machine (WELM), online sequential extreme learning machine (OSELM) and wavelet online sequential extreme learning machine (WOSELM) as well as the MODFLOW software for a 15‐year period monthly. To develop the hybrid artificial intelligence models, the wavelet is employed. First, the effective lags in estimating the qualitative and quantitative parameters of the groundwater are identified using the autocorrelation function (ACF) and the partial autocorrelation function (PACF) analysis. After that, four different models are developed by the selected input combinations and also the ACF and the PACF in the form of different lags for each of ELM, WAELM, OSELM and WOSELM methods. Then, the superior models in simulating the groundwater qualitative and qualitative parameters are detected by conducting a sensitivity analysis. To forecast the electrical conductivity (EC) by the best WOSELM model, the values of the Nash–Sutcliffe efficiency coefficient (NSC), Mean Absolute Error (MAE) and the scatter index (SI) are obtained to be 0.991, 18.005 and 4.28E‐03, respectively. In addition, the most effective lags in estimating these parameters are introduced. Subsequently, the results found by the MODFLOW model are compared with those of the artificial intelligence models and it is concluded that the latter are more accurate. For instance, the scatter index and Nash–Sutcliffe efficiency coefficient values calculated by WOSELM for TDS, respectively, are 5.34E‐03 and 0.991. Finally, an uncertainty analysis is conducted to evaluate the performance of different numerical models. For example, MODFLOW has an underestimated performance in simulating the salinity parameter. [ABSTRACT FROM AUTHOR]

Most of the textile and dying process industries in Tirupur region do not have proper wastewater treatment plants and they discharge the effluents in unlined channels and streams. Due to the issue, the groundwater in Tirupur is highly polluted. For analysing groundwater condition, groundwater modelling is used. For groundwater hydrologist, groundwater models are a vital tool. Nowadays, a lot of computer programs have been used for modelling groundwater. Visual MODFLOW software uses a finite difference method for solving the complexity. They can be used for simulating the behaviour of composite aquifers as well as the effects of irregular boundaries and different processes such as solute transport and groundwater flow. This paper evaluates the impact of industrial effluent in groundwater value in Tirupur region by five different scenarios. [ABSTRACT FROM AUTHOR]

Aquifers are being threatened by overuse, and scenario predictions are convenient to design appropriate planning programs to water management. Numerical modeling is a helpful tool in these analyses, but it is hard to manage with limited data available, which is frequent in developing countries. The aim of the paper is to show that there are other simple and reliable options. The primary objective of this research is to propose and validate a simplified-to-available-data approach, useful for aquifer modeling, followed by scenarios' simulation, based on realistic future events. The Mexican overexploited aquifer Cuautitlán-Pachuca case study assess the responses of the water level under different outflows and infiltration scenarios from 2007 (base year) to 2031. Modflow software allowed the model calibration with 2007 data, and further spatial and temporal evolution of the piezometric level. The aquifer is the main water supplier for economic activities, and population in the northern region of Mexico City and outflows are continuously increasing, despite its severe overexploitation and even stronger negative impacts in the decline water levels are predicted in this study. A previous study reported −194.97 hm/year deficit in 2010, and this paper predicts the strongest effect due to overpumping caused by the population growth that would intensify the deficiency up to −236.29 hm/year. The results have revealed to decision makers the urgency to prevent the aquifer's irreversible impairment, with a proper operation and management planning. This paper provides a contribution for simplifying conceptual models allowing to predict aquifers' outcome scenarios with limited data. [ABSTRACT FROM AUTHOR]

Conflict-resolution models can be used as practical approaches to consider the contradictions and trade-offs between the involved stakeholders in integrated water resource management. These models are utilized to reach an optimal solution considering agents interactions. In this paper, a new methodology is developed based on multi-objective optimization model (NSGA-II), groundwater simulation model, M5P model tree, fallback bargaining procedures and social choice rules to determine the optimal groundwater management policies with an emphasis on resolving conflicts between stakeholders. By incorporating the multi-objective simulation-optimization model and bargaining methods, the optimal groundwater allocation policies are determined and the preferences of the stakeholders as well as social criteria such as justice are also considered. The obtained data set, based on Monte Carlo analysis of calibrated MODFLOW model, is used for training and validating the M5P meta-models. The validated M5P meta-models are linked with NSGA-II to determine the trade-off curve (Pareto front) for the objectives. Social choice rule and fallback bargaining methods, as conflict-resolution models, are applied to determine the best socio-optimal solution among stakeholders, and their results are compared. The effectiveness of the proposed methodology is verified in a case study of Darian aquifer, Fars province, Iran. Results indicated that the solutions obtained by the proposed conflict-resolution approaches have an appropriate applicability. Total groundwater withdrawal, after applying the optimal groundwater allocations, reduced to 20.85 MCM, resulting in a 4.62 m increase in the mean groundwater level throughout the aquifer. [ABSTRACT FROM AUTHOR]

This study aimed to control land subsidence by improving the groundwater balance in the Varamin plain using the Groundwater Modelling System software and a multi-criteria decision model. For this purpose, aquifer level quantification and subsidence rate simulation were performed with the MODFLOW model and SUB package, respectively. The results showed a 6 m decrease in the aquifer level over a 5-year period and the subsidence rate in the central parts was 37 cm. Accordingly, the aquifer was evaluated by considering eight different restoration strategies based on reduced exploitation and artificial feeding. The results showed that the environmental criterion related to the subsidence adjustment index had the highest weight (0.27) and was introduced as the most important decision-making criterion. The evaluation of the results and priorities using the Complex Proportional Assessment (COPRAS) method showed that a 30% reduction in exploitation with artificial feeding is the best restoration strategy and can improve the subsidence rate and aquifer level by 36% and 76%, respectively, over a 5-year period (2024). [ABSTRACT FROM AUTHOR]

The necessity to preserve, reuse, and recycle water is becoming increasingly significant for both environmental and economic sustainability. Conservation of groundwater resources in Belgium is coming under increasing threat due to the variability of climate, rapid urbanization, and population growth. Environmental challenges, as well as rising costs associated with surface water reservoirs, have encouraged water professionals to explore an adequate and sustainable adaptation strategy. Nowadays, aquifer storage and recovery (ASR) is an effective technique and widely applied for seasonal or emergency water storage in an environmentally acceptable, sustainable manner. The work described in this paper explores the potential of ASR to enhance the buffer capacity of water supply systems in pilot sites (Herent Bijlok and Winksele Kastanjebos in Belgium). A conceptual groundwater flow model was developed using the finite-difference code, MODFLOW, for these representative sites. After calibration, the steady-state model was utilized initially for transient simulation, prediction simulation, and later on scenario analysis. The scenario analysis was performed primarily on individual wells and afterward on two multiple wells. The water balance components of the winter and summer stress period showed an increase in groundwater heads during winter months while decreasing throughout the drier periods. Furthermore, among individual ASR wells, one achieved 97% recovery efficiency (RE) while multiple ASR wells attained above 100% RE. Overall, the study indicates that the ASR tool provides an attractive alternative to increasing storage capacity and ensures a sustainable long-term supply of fresh water in the study site of Belgium. [ABSTRACT FROM AUTHOR]

Groundwater, essential for supplying drinking water to half of the global population and supporting nearly half of all irrigation needs, faces significant contamination risks. These risks pose serious threats to human health and ecosystem integrity, driven by increasing pressures from both concentrated and diffuse pollution sources, as well as from growing exploitation. The presented research was conducted with the dual objectives of identifying sources of nitrate contamination (up to 128.1 mg/L) in an oxic groundwater source (Perkićevo, Serbia) and proposing an optimal extraction regimen to ensure a sufficient supply of potable water. Correlations between chemical elements' concentrations and principal component analysis (PCA) indicated a significant relationship between anthropogenic impact indicators (NO3−, Na+, B, Cl−, SO42−, KMnO4 consumption, and electroconductivity), unambiguously showing that groundwater quality was primarily impacted by untreated sewage inflow and confirming nitrate's tracer behavior in oxic environments. The spatial distribution of selected parameter concentration gradients highlighted the expansion and distribution of the contamination front. A numerical groundwater flow model (Vistas 4 and Modflow) was applied to determine the groundwater flow direction and the quantity of groundwater originating from different parts of the investigated area. Through four simulated groundwater extraction scenarios, Scenario 2, with an average extraction rate of 80 L/s from 12 wells, and Scenario 3, with an average extraction rate of 75 L/s and 4 additional wells, were identified as the most optimal, providing a sufficient quantity of adequately sanitary water. [ABSTRACT FROM AUTHOR]

Water scarcity poses a significant challenge in arid and semi-arid regions, necessitating a focused exploration of groundwater resources. Egypt, confronted with various water challenges, particularly in its Western Desert, relies heavily on groundwater as the exclusive water source due to the presence of the Nubian Sandstone aquifer. Effective groundwater management in this region is imperative. This study delves into the hydrogeological characteristics of the Nubian Sandstone aquifer system (NSAS) in the prominent New Valley Oases--Kharga, Dakhla, and Farafra--where agricultural activities heavily depend on groundwater. The primary objective entails a meticulous temporal assessment of the impact of groundwater development on aquifer behavior, groundwater levels, and drawdown. Employing a remote sensing approach, agricultural expansion from 1995 to 2020 was scrutinized. The Visual MODFLOW package served as a robust tool for simulating groundwater flow in the study areas. Noteworthy findings reveal an upward trajectory in agricultural crop areas, escalating by approximately 6% from 1740 km² in 1995 to 1850 km² in 2020. Concurrently, drawdown, influenced by current groundwater extraction, is anticipated to range from 0.5 to 5 meters per year. To ensure the sustainable development of these areas, stringent regulations must be implemented, underscoring the imperative for judicious groundwater management practices. This research underscores the critical need for informed decision-making and proactive measures to address the evolving dynamics of groundwater resources in the New Valley Oases. [ABSTRACT FROM AUTHOR]

With the gradual improvement in coal mining efficiency, the disturbance of groundwater systems caused by high-intensity mining also increases, leading to challenges in maintaining mine safety and protecting water resources in mining areas. How to accurately describe the dynamic changes in the groundwater system under mining and quantitatively predict mine water inflow are currently major problems to be addressed. Based on a full analysis of the response characteristics of a groundwater system to the extraction disturbance, this paper presents a new method to establish a mine hydrogeological conceptual model that can accurately represent the water inrush process. The unstructured-grid package of MODFLOW is used to accurately characterize the formation structure and finally make accurate water inflow predictions. Taking the Caojiatan coal mine in Shaanxi Province, China, as an example, a numerical model of unstructured water inflow is established, and the changes in the water inflow source and intensity are quantitatively evaluated. Compared with the traditional water inflow prediction method, the prediction accuracy of the new model is improved by 12–17%, which is achieved by detailing the response of the complex groundwater system under high-intensity mining conditions. The method presented in this paper has great significance and applicatory value for obtaining a comprehensive understanding of the disturbance characteristics of human underground engineering activities (e.g., coal mining) on groundwater systems, as well as accurately predicting water inflow.

In arid regions, the optimal utilization of river channels to collect rainwater resources can effectively alleviate the problem of water scarcity. This paper employs visual MODFLOW software to simulate the infiltration volume of rainwater under different schemes, with the objective of identifying the optimal infiltration volume. The results indicate that the infiltration volume of rainwater is 0.6, 79.7, 36.5, 62, and 10,000 m3 under different design schemes. COMSOL software is employed to simulate the infiltration situation of rainwater under different schemes, and the scheme with the most favourable infiltration effect is identified. The simulation results indicate that scenarios 2, 4, and 5 demonstrate superior early-stage infiltration performance. Ultimately, the optimal infiltration scheme is selected by integrating the infiltration volume, infiltration effect, construction, economic, and ecological factors to achieve the objective of enhancing rainwater harvesting and utilization. This study offers effective and reasonable measures for addressing the challenge of water resources management in arid regions. It provides suitable reference schemes for river channel rainwater storage projects and offers innovative approaches to rainwater resource utilization, thereby contributing to the alleviation of water scarcity in arid areas.

Wetlands are vulnerable to groundwater extraction, which has proven detrimental to aquatic ecosystems around the planet. As wetlands rank among the world's most endangered ecosystems, versatile strategies are required to protect them. This paper provides a modelling-based method to delineate protection buffers in wetlands subject to groundwater extraction. The technique is sufficiently flexible to cater to a wide variety of conditions, and simple enough to underpin management decisions on a daily basis. A numerical model is used to obtain a map of the critical rate of groundwater abstraction, based on the distance between wetlands and suitable discharge thresholds. The outcomes determine the allowed pumping rate at any point under steady and transient-state conditions. A new iteration is developed every time a new pumping allowance is made. This procedure is demonstrated by means of hypothetical scenarios, as well as by a case study application in the Valle del Cauca region, Colombia. [ABSTRACT FROM AUTHOR]

The Triffa plain covering about 307 km2 is located in the semiarid region of northeastern Morocco. The cover consists of Quaternary and Mio-Pliocene formations, including alluvial material, silt, sandstone, limestone, clay, and marl, underlain by a sequence of Jurassic carbonates and clastics. Two principal aquifers occur in this region: (1) An unconfined aquifer hosted by the Quaternary formations, which opens up on the coastal plain of Saïdia, giving rise to the Aïn Chebbak and Aïn Zebda springs; and (2) a confined aquifer hosted by the underlying Liassic (Jurassic) formations, composed of limestone and dolostone. In this paper, we present a conceptual hydrogeological model for the Triffa aquifer, which opens laterally into the Saïdia aquifer, based on borehole data, bedrock geology, hydrodynamic parameters, piezometric maps, and time series groundwater level and precipitation data, obtained from several meteorological stations and pumping wells. These comprehensive data were incorporated in the Geographic Information System platform and processed using groundwater modeling software, with the development of the numerical model and its limitations discussed in detail in the present work. Subsequently, we evaluated the impact of climate change on the Triffa aquifer, assuming three different climate scenarios developed by the Intergovernmental Panel on Climate Change. These were the B1—low, A1B—mean, and A1F1—extreme scenarios, which we modeled by simulating a decrease in the recharge in all of the study area up to year 2099 that would correspond to 9, 19, and 47%, respectively. The calibration of the model in steady and transient states produced a good agreement between the observed and simulated heads. The simulation of the impact of climate change on groundwater by a decrease in the recharge highlights the groundwater drawdown occurring in this region. This work can significantly help the authorities in the sustainable management and exploitation of local groundwater. [ABSTRACT FROM AUTHOR]

The paper presents an evaluation of the combined use of the HYDRUS and SWI2 packages for MODFLOW as a potential tool for modeling recharge in coastal aquifers subject to saltwater intrusion. The HYDRUS package for MODFLOW solves numerically the one-dimensional form of the Richards equation describing water flow in variablysaturated media. The code computes groundwater recharge to or capillary rise from the groundwater table while considering weather, vegetation and soil hydraulic property data. The SWI2 package represents in a simplified way variable-density flow associated with saltwater intrusion in coastal aquifers. Combining these two packages within the MODFLOW framework provides a more accurate description of vadose zone processes in subsurface systems with shallow aquifers, which strongly depend upon infiltration. The two packages were applied to a two-dimensional problem of recharge of a freshwater lens in a sandy peninsula, which is a typical geomorphologic form along the Baltic and the North Sea coasts, among other places. Results highlighted the sensitivity of calculated recharge rates to the temporal resolution of weather data. Using daily values of precipitation and potential evapotranspiration produced average recharge rates more than 20% larger than those obtained with weekly or monthly averaged weather data, leading to different trends in the evolution of freshwater-saltwater interfaces. Root water uptake significantly influenced both the recharge rate and the position of the freshwater-saltwater interface. The results were less sensitive to changes in soil hydraulic parameters, which in our study were found to affect average yearly recharge rates by up to 13%. [ABSTRACT FROM AUTHOR]

The water scarcity and its socio-economic significance with respect to water demand for agriculture, industry and tourism, in the northeastern Tunisia (Cap-Bon), are at the origin for prospecting new groundwater resources and for developing groundwater models that can be used to their control and management. The Takelsa multilayer aquifer is one of the important aquifers of the northeast in Tunisia. It is among the aquifers which are still slightly known in spite of its exploitation since the 80s. This paper is aimed to quantify the groundwater recharge of the Takelsa multilayer aquifer. The groundwater recharge is assessed using WetSpass which is a physically based model integrated in GIS ArcView as a raster model. The simulated results are given seasonally and yearly at the grid level. These results are subsequently incorporated in the groundwater flow simulation model MODFLOW in order to simulate the hydraulic head distribution. The steady state groundwater flow calibration was obtained by comparing the observed and the simulated hydraulic heads. The mean annual evapotranspiration, surface runoff and groundwater recharge simulated by WetSpass, are 461, 92 and 22 mm, respectively. The groundwater recharge represented 4.3% of the precipitation while 17.8% and 89% are respectively lost by surface runoff and evapotranspiration. [ABSTRACT FROM AUTHOR]

Metropolitan Tuguegarao Water District is one of Northern Luzon's leading groundwater consumers, averaging a monthly extraction of 1.43 million cubic meters. Since its inception, the water supply system has relied mainly on groundwater, triggering well sources to deteriorate. While recharge through soil moisture accounting is sufficient for safe yield estimation, a groundwater flow model was created to account for the spatiotemporal distribution of groundwater levels in response to hydraulic and hydrologic stresses. MODFLOW, a finite-difference model, aided in the development of local grids from a regional basin--the Cagayan Valley Aquifer System. A three-dimensional numerical flow model was satisfactorily calibrated, with the goodness offit between the simulated and observed heads determined through three statistical indices: Mean Absolute Error (0.5376 m), Root-Mean-Squared Error (0.8061 m), and Normalized Root-Mean-Squared Error (2.23%). The model simulated a 10.60% recharge from rainfall for the regional basin, which is comparable to the average recharge rate estimated by the Department of Environment and Natural Resources. Continuous pumping demonstrated head reductions that exceeded critical levels in four wells at current rates, 12 wells at adjusted rates, and five wells affected by pumping the proposed wells. Notably, four production wells, which constitute 31% of the present groundwater production, remained below critical levels. With the proposed surface water facility, however, groundwater production may be reduced up to 63%, allowing for the resource to recover. The findings of this research on all model scenarios showed that groundwater levels will decrease in the coming years. Thus, efficient planning for sustainable resource use is crucial. This study presents the relevance of numerical hydraulic analysis for a more comprehensive groundwater resource assessment. [ABSTRACT FROM AUTHOR]

This study presents the development of a comprehensive three-dimensional groundwater flow model for the Erbil Basin utilizing the Groundwater Modeling System (GMS). The Erbil Basin, situated in the Kurdistan Region of Iraq, is a vital water resource area facing increasing water demands and environmental challenges. The three-dimensional nature of the groundwater flow system is crucial for accurately understanding and managing water resources in the basin. The modeling process involved data collection, geological and hydrogeological characterization, conceptual model development, and numerical simulation using GMS software MODFLOW 2000 package. Various parameters such as hydraulic conductivity, recharge rates, and boundary conditions were integrated into the model to represent the complex hydrogeological conditions of the basin. Model calibration was performed by comparing simulated groundwater levels with observed data from monitoring wells across the basin, using the automatic calibration method of automated Parameter Estimation (PEST). Pilot points were applied to adjust the hydraulic conductivity in the model area spatially. Sensitivity analysis was conducted to assess the influence of key parameters on model predictions and to identify areas of uncertainty. The developed three-dimensional groundwater flow model provides valuable insights into the dynamics of groundwater flow, recharge-discharge mechanisms, and potential impacts of future scenarios such as climate change and water resource management strategies. It serves as a useful tool for decision-makers, water resource managers, and researchers to evaluate different management scenarios and formulate sustainable groundwater management policies for the Erbil Basin. In conclusion, this study demonstrates the effectiveness of using GMS for developing three-dimensional groundwater flow models in complex hydrogeological settings like the Erbil Basin, contributing to improved understanding and management of groundwater resources in the region. [ABSTRACT FROM AUTHOR]

At the neighbourhood of several drainage objects types in shallow aquifer like fully penetrated wells, partially penetrated wells, well with laterals, horizontal drainages etc. groundwater flow forms contain frequently 2D/3D singular behaviours (e.g. logarithmical or polar singularities), which require special attention by coarse grid simulations Groundwater reservoir modelling. The first objective of the paper is to test the accuracy of Finite Volume Methods with specific reference to one of the most used standard reservoir modelling software in groundwater modelling PMWIN/MODFLOW (i.e. Processing MODFLOW for Window), Chiang (2001). The numerical experiment will be accomplished mainly for fully penetrating well (W) and partially penetrating well (ppW) using various discretization size. It will be shown that the standard Well Index method (Peaceman 1983), currently used by coarse grid simulations, allows the local correction in well blocks only for hydraulic head (or pressure) in the wellbore obtained by coarse grid simulation for imposed global discharge/recharge rate of the well. In the paper an extension of the WI based method will be proposed which allows also the well discharge rate correction by coarse grid modelling for imposed hydraulic head (imposed pressure) in the well. The proposed method is proved with several numerical simulation examples for fully wells and ppWells. [ABSTRACT FROM AUTHOR]

Hydrodynamic analysis was used as the methodological approach to simulate the groundwater regime and quantify the groundwater balance in the extended area of the open-cast mine 'Jakovačka Kumša'. The study area includes a part of Belgrade Groundwater Source, located along the Sava River, in the immediate vicinity of the mine. Sand is excavated there and used as construction material. The paper analyzes and synthesizes data on local geology and hydrogeology, and portrays a three-dimensional hydrogeological model of the study area. The hydrogeological model is transformed into a hydrodynamic model applying the numerical method of finite differences and the Modflow software code. The modeled area and time interval are then discretized by importing the hydrogeological parameters of the porous medium and specifying the initial and boundary conditions of the model. The paper also includes the results of hydrodynamic modeling of the aquifer regime in the form of piezometric-head distribution charts, as well as the groundwater balance. The 3D hydrodynamic model set up in this manner constitutes a basis for hydrodynamic prognostic calculations and assessment of sand mining impact on groundwater quality in that part of Belgrade Groundwater Source.

One of the most essential groundwater model components is accurate information about the recharge values within the input data, often introduced to a groundwater model as a percentage of rainfall on aquifers. Recharge values are influenced by many temporal and spatial factors. This paper suggests the use of a SWAT model for surface water simulation and the estimation of recharge rates. In this research, sensitivity analysis, calibration, validation and uncertainty analysis of results were performed by SWAT-CUP software. Due to the semi-distributed features of SWAT and the difficulty of calculating groundwater distributed parameters, recharge values estimated by SWAT were used in a MODFLOW model for groundwater simulation at steady and unsteady states. This method was applied in the Firoozabad basin, which is one of the most suitable agricultural basins for modeling surface water and groundwater in Iran. After MODFLOW model calibration, hydrodynamic coefficients of the aquifer were determined and the sensitivity of the model was checked for hydraulic conductivity and discharge rate of wells. In order to prove confidence, the model was validated. SWAT and MODFLOW models were successfully tested and the results of the combination of the two models were found to be acceptable. [ABSTRACT FROM AUTHOR]