Groundwater Model Research Articles

Water Sample Collection Methods for 222Rn Analysis by Scuba Diving: Insights on Groundwater Flushing of Anchialine Cave Systems of the Yucatan Peninsula

AbstractRadon (222Rn) is a widely used tracer in groundwater and surface water studies. In some applications of radon, samples need to be collected from deep submerged areas or discharge points such as caves or springs, locations typically accessed by scuba diving. However, there are no established sampling methods for collecting water by scuba diving for Rn analysis. We assessed four underwater sample collection methods: (a) injection into a catheter bag followed by transfer to a bottle after the dive, (b) air purging and then filling of a bottle by allowing gas to escape, (c) air purging followed by gas escape, and then overfilling of water with a syringe, and (d) collection with a syringe followed by transfer to a bottle. The samples were collected from the anchialine caves of the Yucatan Peninsula which are the longest underwater cave systems. The samples were analyzed using the same Rn‐in‐air analyzer and protocols. Statistical comparison of sampling at the same location with different methods showed no significant differences in Rn activity. No collection method is superior in terms of measurement quality; operational simplicity is thus preferred. Statistically significant differences in activity were observed between fresh and saline samples from the same cave, with higher activities in the fresh samples, regardless of sampling method. The saline groundwater therefore has a lower residence time, suggesting vigorous landwards flow. Our assessment shows that in situ sampling of discrete water samples for Rn tracing by divers is a useful and powerful approach allowing the study of otherwise impossible sites.

Understanding Climate Change and Anthropogenic Impacts on the Salinization of Low‐Lying Coastal Groundwater Systems

AbstractFresh coastal groundwater is a valuable water resource of global significance, but its quality is threatened by saltwater intrusion. Excessive groundwater abstraction, sea‐level rise (SLR), land subsidence and other climate‐related factors are expected to accelerate this process in the future. The objective of this study is to (a) quantify the impact of projected climate change and (b) explore the role of individual hydrogeological boundaries on groundwater salinization of low‐lying coastal groundwater systems until 2100 CE. We employ numerical density‐dependent groundwater flow and salt transport modeling for this purpose, using Northwestern Germany as a case. Separate model variants are constructed and forced with climate data, that is, projected SLR and groundwater recharge, as well as likely ranges of other hydrogeological boundaries, including land subsidence, abstraction rates and drain levels. We find that autonomous salinization in the marsh areas, resulting from non‐equilibrium of the present‐day groundwater salinity distribution with current boundary conditions, is responsible for >50% of the salinization increase until 2100 CE. Sea‐level rise, land subsidence and drain levels are the other major factors controlling salinization. We further show that salinization of the water resources is a potential threat to coastal water users, including water suppliers and the agrarian sector, as well as coastal ecosystems. Regional‐scale uplifting of drain levels is identified as an efficient measure to mitigate salinization of deep and shallow groundwater in the future. The presented modeling approach highlights the consequences of climate change and anthropogenic impacts for coastal salinization, supporting the timely development of mitigation strategies.

Statistical Study of Groundwater Salinity at Lake Dayet Erroumi, Morocco

Statistical Study of Groundwater Salinity at Lake Dayet Erroumi, Morocco

Can Agricultural Managed Aquifer Recharge (Ag‐MAR) Recover Return Flows Under Prior Appropriation in a Warming Climate?

AbstractGroundwater return flow to streams is important for maintaining aquatic habitat and providing water to downstream users, particularly in irrigated watersheds experiencing water scarcity. However, in many agricultural regions, increased irrigation efficiency has reduced return flows and their subsequent in‐stream benefits. Agricultural managed aquifer recharge (Ag‐MAR)—where artificial recharge is conducted via irrigation canals and agricultural fields—may be a tool to recover these return flows, but implementation is challenged by water supply and water management. Using climate‐driven streamflow simulations, an integrated operations‐hydrology model, and a regional groundwater model, we investigated the potential for Ag‐MAR to recover return flows in the Henrys Fork Snake River, Idaho (USA). We simulated potential Ag‐MAR operations for water years 2023–2052, accounting for both future water supply conditions and local water management rules. We determined that Ag‐MAR operations reduced springtime peak flow at the watershed outlet by 10%–14% after accounting for return flows. Recharge contribution to streamflow peaked in July and November, increasing July–August streamflow by 6%–14% and November–March streamflow by 9%–14%. Furthermore, sites where Ag‐MAR was conducted incidental to flood irrigation had more water available for recharge, compared to sites requiring recharge rights, which are junior in priority to agricultural rights. Mean annual recharge volume for the incidental recharge sites averaged 12% of annual natural streamflow, ranged from 269 to 335 Mm3, and was largely available in April and October. We demonstrate Ag‐MAR can effectively recover groundwater return flows when applied as flood irrigation on agricultural land with senior‐priority water rights.

Deciphering chemical and physical processes that give rise to natronization in a shallow aquifer in an arid zone

Groundwater provides a reliable and stable alternative to surface water resources in arid and semiarid regions to meet human and environmental needs. However, excessive exploitation in the last decades has led to significant salinization of groundwater and soils in many parts of the world. In the highlands of central-north Mexico, a number of agriculturally used aquifers show increasing salinization effects. Tierra Nueva is a case where salt precipitations in recent years have made land mostly unsuitable for agriculture. It is assumed that the intensive irrigation under dry climatic conditions, together with the presence of argillaceous horizons at shallow depth and the alteration of Na-rich volcanic rocks, determine the occurrence of specific salinization processes producing evaporite minerals in excess. This investigation provides physical and chemical evidence of groundwater processes explaining the accumulation of solutes in groundwater and soils. It shows that the principal evolutionary processes in the studied aquifer were water-rock interactions and evaporation, while ionic exchange processes dominated the water circulating through the clay-sandy materials of the valley. Geochemical models show that recharging water dissolved CO2 from the unsaturated zone, and reacted with silicates (i.e. hydrolysis of albite, K-feldspar, and biotite), underwent cation exchange, and precipitated kaolinite. In the discharge area, the mineral natron was dissolved, while thermonatrite, natrolite (Na-natrolite), nontronite (Ca-nontronite, K-nontronite, Mg-nontronite, Na-nontronite) were formed, among other reactions. This salinization process eventually leads to soils which are unsuitable for agricultural activities. The study of this phenomenon represents an important contribution to the understanding of the implications of the expansion of arid and semiarid lands.

Are haloclines distributional barriers in anchialine ecosystems? Physiological response of cave shrimps to salinity.

Anchialine systems are coastal groundwater habitats around the world which host a unique community of cave adapted species (stygobionts). Such communities are expected to be separated by haloclines into either fresh or saline groundwater communities, hence climate changes (e.g., eustatic sea level shifts) and anthropic driven changes (e.g., salinization) may have a great impact on these stygobiont communities. Here we used cave-restricted species of Typhlatya from the Yucatan Peninsula as models to identify physiological capacities that enable the different species to thrive in marine groundwater (T. dzilamensis) or fresh groundwater (T. mitchelli and T. pearsei), and test if their distribution is limited by their salinity tolerance capacity. We used behavior, metabolic rates, indicators of the antioxidant system and cellular damage, and lactate content to evaluate the response of individuals to acute changes in salinity, as a recreation of crossing a halocline in the anchialine systems of the Yucatan Peninsula. Our results show that despite being sister species, some are restricted to the freshwater portion of the groundwater, while others appear to be euryhaline.

Multi-objective double layer water optimal allocation and scheduling framework combing the integrated surface water – groundwater model

Balancing the water consumption of agricultural and ecological is the key point of sustainable social and economic development in an inland river basin. The growth of desert riparian forests in inland river basins mainly depends on a certain phreatic water table depth (PWTD). The main object of this study was to allocate and schedule water resources to regulate the PWTD and satisfy agricultural water demand. Therefore, a multi-objective double layer optimal allocation and scheduling framework based on the computationally efficient integrated surface water-groundwater model (ISGWM), which can simulate the surface water processes, groundwater recharge and discharge processes, and PWTD changes, was constructed and applied to the mainstream of Tarim River Basin (TRB). The top layer model of the framework is an optimal ecological water allocation model, and its optimal allocation results are used as the initial solution of the bottom layer model. The results show that under 5 different inflow frequencies, the agricultural water shortage rate is 0, 17.38 %, 17.41 %, 14.06 %, and 19.94 %, respectively. The PWTD regulation has a great performance. After the optimal scheduling, the proportions of good growth of the control area behind the gate under different inflow frequencies were 98.18 %, 98.18 %, 98.18 %, 90.91 %, and 94.55 %. Agricultural water shortage is mainly due to the non-uniformity distribution of intra-annual inflow and the lack of controlling hydraulic engineering. The regulation of PWTD can guarantee the growth of desert riparian forests on both sides of the mainstream of TRB. Besides, we explored the feasibility of exploiting groundwater to supplement agricultural water consumption. The groundwater exploitation should be controlled within the scope of not causing excessive increase of PWTD (difference between PWTD and target depth <1 m), due to the groundwater exploitation to supplement agricultural water will lead to the increase of PWTD. Overall, this framework, which regulates the PWTD with the change of ecological water supply based on the ISGWM, provides a new idea for the allocation and scheduling of agricultural and ecological water resources in arid inland river basins. It also provides a new method for the coupled cooperative operation of surface water and groundwater.

Effects of Salinity and Ca2+: Mg2+ Ratio on Growth Performance and Survival of Penaeus vannamei (Boone, 1931) Reared in Inland Saline Ground Water

Background: A 60-day experiment was conducted to evaluate the combined effect of salinity and Ca2+: Mg2+ ratio on the growth performance and survival of Penaeus vannamei reared in inland saline ground water (ISGW) at ICAR-Central Institute of Fisheries Education (CIFE), Rohtak Centre, Haryana, India. Methods: The study used three different salinities viz. T1 (5 ppt), T2 (10 ppt) and T3 (15 ppt) with four different level of Ca2+: Mg2+ rations such as 1:1, 1:2, 1:3 and 1:4. juveniles of P. vannamei with average body weight of 3.70±0.02 g, were stocked in 100 L capacity of circular plastic tanks. Total 36 experimental tanks were used as experimental unit. The stocking densities were 20 animals in each tank and each treatment were kept in triplicate followed the factorial design (3×4). Result: P. vannamei expressed better growth performance in terms of SGR, FCR, FER and PER in the T2 and T3 fortified Ca2+: Mg2+ ratio of 1:3. Lowest growth observed in T1 fortified with Ca2+: Mg2+ ratio 1:1. The study found 100% survival in T2 and T3 fortified with Ca2+: Mg2+ ratio of 1:3 compared with other treatment groups, which showed less than 80% survival. Based on the results, it can be concluded that the better growth performance, survival of P. vannamei observed in 10 and 15 ppt salinities of ISGW fortified with 1:3 ratio of Ca2+: Mg2+.

Development of a coupled surface water–groundwater model for the spatiotemporal simulation of river–aquifer interactions

AbstractIntegrating surface and groundwater use is a crucial part of water management. When one type of water is depleted, the other follows suit because of the constant movement and interaction between them. Therefore, the primary objective of this research is to establish a method by which the water evaluation and planning system (WEAP) surface water model and the MODFLOW groundwater model can communicate with one another. This article aims to demonstrate the interdependence of groundwater and surface water. Here, we use MODFLOW to model the saturated soil region and the soil moisture method to model the unsaturated soil region. The interaction between surface water and groundwater will affect the region's water resources and how they will operate under the continuance of existing practices. The simulation of saturated and unsaturated soil zones using a connected model of surface and groundwater employing all the hydroclimatology balance components is one of the most significant accomplishments of this research. The findings show that the (Iran) Sonqor Plain's maximum aquifer recharge throughout the months of November to May during a period of 30 years (October 1991 to September 2020) ranges between 1.5 and 2.6 million m³. A lack of recharge from irrigation water infiltration occurs in some of these months in addition to rain. The highest rate of groundwater level increase in this area is 4.5 m yr⁻¹ as a result of the distribution of irrigation water provided from the dam in the north‐western region.

Using Expert Participation to Evaluate the Accuracy of Hand-Drawn Water-Table Maps.

Water-table maps are fundamental to hydrogeological studies and a manual, hand-drawn method is still commonly used to produce them. Despite this, the accuracy and variability of such maps have received little attention in international literature. In a unique experiment, 63 groundwater professionals drew water-table equipotential contours based on the same dataset of point measurements and were asked to infer flow directions and predict groundwater elevations at predefined locations. The root mean squared error (RMSE) for the average map calibration data was 10.5 m, which is accuracy comparable to numerical groundwater models. This study confirmed that to produce hand-drawn water-table maps, practitioners seek to not only fit the spatial data, but also to conform to their own cognitive model of hydrogeological concepts and processes. The calibration accuracy increased with experience; from a RMSE of 13.3 m for practitioners with 0-3 years of experience to a RMSE of 9.2 m for those with four or more years. Despite considerable variability in the style of the hand-drawn water-table maps, the maps were consistent in their representation of the dominant regional groundwater flow directions. There was less consensus, however, in predicting the direction of surface water-groundwater interaction for a stream reach. Hand-drawn water-table mapping remains useful and valid, especially as a starting point for hydrogeological conceptualization, yet further work is required to resolve issues around transparency, repeatability, and reproducibility.

Assessing the Impact of Groundwater Recharge on Underground Reservoir Replenishment in Eastern Uttar Pradesh, India

Groundwater is considered a fresh resource of water and its uses have tremendously increased in the recent past due to an increase in population, rapid urbanization, and industrialization. In India, the groundwater level is declining in some parts of the country due to over-exploitation, low or negligible recharge of aquifer systems, and unsustainable development of groundwater resources. The groundwater modeling is an important tool for studying the past and present groundwater behavior and in the development of future strategies for sustainable groundwater management plans. To study the Impact of groundwater recharge on the replenishment of underground reservoir, Ballia district of Uttar Pradesh has been selected which is one of the districts of the most populous state of India, Uttar Pradesh. An attempt has been made to develop a groundwater model using Modflow software to simulate the groundwater trends and predict future groundwater heads. The calibration and validation of the model were done for 5 years and 3 years respectively. The correlation coefficient for calibration and validation was found 0.85 and root mean square errors vary from 2.89 to 3.2m variation in future trends of groundwater heads. The results of the study show that the developed model can be effectively used to predict the future groundwater heads. The groundwater flow was observed from the northwest to southeast direction. It was predicted from the study that groundwater draft will increase by 10% with a decrease in groundwater level by approximately 0.24 m in the north-west direction by the year 2025. However, no impact was observed in the south side of the district and it was predicted that the groundwater level would remain the same in this zone during the next 3 years.

Examining site intervention efficacy and uncertainties with conceptual Bayesian networks: preventing offsite migration of DNAPL and contaminated groundwater.

For contaminated sites, conceptual site models (CSMs) guide the assessment and management of risks, including remediation strategies. Recent research has expanded diagrammatic CSMs with structural causal modeling to develop what are nominally called conceptual Bayesian networks (CBNs) for environmental risk assessment. These CBNs may also be useful for problems of controlling and preventing offsite contaminant migration, especially for sites containing dense nonaqueous phase liquids (DNAPLs). In particular, the CBNs provide greater clarity on the causal relationships between source term, onsite and offsite migration, and remediation effectiveness characterization for contaminated DNAPL sites compared to traditional CSMs. These ideas are demonstrated by the inclusion of modifying variables, causal pathway analysis, and interventions in CBNs. Additionally, several new extensions of the CBN concept are explored including the representation of measurement variables as lines of evidence and alignment with conventional pictorial CSMs for groundwater modeling. Taken as a whole, the CBNs provide a powerful and adaptable knowledge representation tool for remediating subsurface systems contaminated by DNAPL.

Lithium and water: Hydrosocial impacts across the life cycle of energy storage

AbstractAs a key ingredient of batteries for electric vehicles (EVs), lithium plays a significant role in climate change mitigation, but lithium has considerable impacts on water and society across its life cycle. Upstream extraction methods—including open‐pit mining, brine evaporation, and novel direct lithium extraction (DLE)—and downstream processes present different impacts on both the quantity and quality of water resources, leading to water depletion and contamination. Regarding upstream extraction, it is critical for a comprehensive assessment of lithium's life cycle to include cumulative impacts related not only to freshwater, but also mineralized or saline groundwater, also known as brine. Legal frameworks have obscured social and ecological impacts by treating brine as a mineral rather than water in regulation of lithium extraction through brine evaporation. Analysis of cumulative impacts across the lifespan of lithium reveals not only water impacts in conventional open‐pit mining and brine evaporation, but also significant freshwater needs for DLE technologies, as well as burdens on fenceline communities related to wastewater in processing, chemical contaminants in battery manufacturing, water use for cooling in energy storage, and water quality hazards in recycling. Water analysis in lithium life cycle assessments (LCAs) tends to exclude brine and lack hydrosocial context on the environmental justice implications of water use by life cycle stage. New research directions might benefit from taking a more community‐engaged and cradle‐to‐cradle approach to lithium LCAs, including regionalized impact analysis of freshwater use in DLE, as well as wastewater pollution, cooling water, and recycling hazards from downstream processes.This article is categorized under: Human Water &gt; Human Water Human Water &gt; Water Governance Human Water &gt; Water as Imagined and Represented Science of Water &gt; Water and Environmental Change

Groundwater modelling in SWAT+: Considerations for a realistic baseflow simulation

Hydrological models are valuable tools that support the evaluation and management of water resources. Among catchment scale models, SWAT has been widely used, and a revision of this model, SWAT+, was recently released. Groundwater simulation has been pointed out as one of the main weaknesses of these models, and despite the introduction of some improvements in the new version, an accurate simulation of groundwater flow is still a pending task. One of the most common issues is the inability of the model to maintain baseflow during long dry periods. Baseflow is common in aquifer areas and has great relevance for water quality and ecosystems. Although some authors proposed different solutions to its inaccurate simulation (e.g., editing aquifers configuration, coupling with other models, etc.) this work aimed to determine if a realistic groundwater simulation is possible using SWAT+ and determine the reasons why this is not being achieved. For this purpose, a groundwater dominated catchment was modelled, and different calibration approaches were carried out and compared, including strategies such as hard calibration, soft calibration, or sensitivity analysis. A comprehensive analysis of model outputs was crucial to achieve a model with a realistic simulation of groundwater contribution to the streamflow, both in amount and timing. The properly parameterization of some parameters (perco, latq_co, lat_ttime, and especially alpha) was key. Limitations of hard calibration were evidenced, such as the necessity of complementing this strategy with an evaluation of the simulation of hydrological processes. For those parameters governing streamflow components simulation, a detailed description of its functioning is included in this manuscript, together with some guidelines to achieve a statistically accurate model with a realistic groundwater flow simulation. Follow these recommendations will be useful for SWAT users, and will serve to create more reliable models.

Environmental and climatic significance of the Pliocene-Pleistocene calcretes in North Africa

The North African calcretes formed during the Plio-Pleistocene are a prominent and stratigraphically significant palaeoclimatic marker. We studied the calcrete along a north–south transect in Tunisia that crosses the climatic boundaries between the latitudes 33° and 37° N to elucidate the palaeoenvironmental and climatic significance of the calcrete for the Plio-Pleistocene. Macroscopic, petrographic, Scanning Electron Microscopy (SEM), and Cathodoluminescence (CL) observations obtained in the field and from thin sections of the non-powdery horizons of all sites allowed to identify 4 facies: Pisolithic (limestones with clast(s) coated by laminae), laminar (limestones with a succession of laminae), massive brecciated (brecciated limestones), and groundwater facies (limestones with no biogenic features). Notably, soil-forming processes were evident at all sites except for those situated further south, which exhibited characteristics indicative of a groundwater environment. The comparison with modern analogues suggests for our study area the climate was similar to modern central Spain (Hot-summer Mediterranean climate Csa) in central Tunisia which is, in turn, similar to the modern climate in North Tunisia. The climate was characterized by strong seasonal contrast: higher winter rainfall than today followed by long dry hot summers modified by a North-South gradient. This gradient was the result of the interplay between westerly winter winds and the orographic effect of the Atlas Mountains confirming the North Atlantic origin of precipitations. We conclude that during the late Pliocene to early Pleistocene, the climate in Northern Africa was more humid than today, with enhanced winter rainfall at all study sites probably at the same time of the establishment of Saharan humid periods. These humid phases may have been long enough, spanning more than 10.000 years, to reduce recharged groundwater salinity and, subsequently, form thick calcareous soil.

Numerical simulation of groundwater in hyporheic zone with coupled parameter stochastic scheme

Groundwater numerical modeling is a crucial scientific tool for understanding groundwater circulation and supporting regional water resource planning and management. The effectiveness of these models depends largely on the accuracy of hydrogeological parameters within aquifers, which are often spatially heterogeneous and randomly distributed due to complex geological and tectonic factors. Traditional modeling approaches frequently overlook this randomness, compromising the precision and resolution of groundwater simulations. This study focuses on a section of the Qingshui River in the Huaihe River Basin. Using field and laboratory data, probability distribution functions for key parameters like hydraulic conductivity, specific yield, and specific storage were developed. These functions were integrated into the groundwater model to reflect the inherent stochastic nature of aquifer properties. This integration significantly enhanced model accuracy, reducing the root mean square error of simulated water levels from 0.47–1.43 m to 0.13–0.16 m and improving the Nash-Sutcliffe efficiency coefficients (NSE) from −2.96–0.73 to 0.94–0.98. Additionally, the model facilitated analysis of the interactions between river and groundwater, particularly in the hyporheic zone, under various scenarios. It identified spatial and temporal variations in groundwater recharge dynamics and delay effects at different distances from the river channel. For instance, recharge rates at 50 m and 150 m from the river were 0.295 m/day and 0.015 m/day, respectively, indicating stronger recharge closer to the river. The study also assessed the impact of varying river flows, riverbed permeability, and irrigation practices on water exchanges between the river and groundwater. These factors were found to significantly influence the intensity of water exchange, seepage, and groundwater reserves. This research provides valuable insights for managing river-groundwater interactions and analyzing the ecological environment of surrounding groundwater systems, underscoring the importance of incorporating stochastic characteristics into groundwater modeling.

Dietary biochar effect on growth performance, proximate composition, and physiological response of Penaeus vannamei (Boone, 1931) cultured in inland saline groundwater

Transforming raw materials (biomass feedstock) into biochar finds diverse applications across various industries owing to the distinctive characteristics of biochar. This study used biochar as a feed additive for shrimp feeding. A 90-day feeding trial was conducted to assess the impacts of different biochars on growth parameters, haematological parameters, and digestive enzymes of Penaeus vannamei reared in inland saline groundwater of 10 ppt salinity. The finely ground biochar (0.5 mm) prepared from different sources was mixed with the commercially available shrimp feed (35 % crude protein, 5 % crude fat, and 4 % crude fibre), viz., T1, paddy straw biochar (PSB); T2, sugarcane bagasse biochar (SBB); T3, banana peduncle biochar (BPB); and the control group (C) without any biochar. Twenty shrimp (10.24 ± 0.01 g) were stocked in each triplicate. Banana peduncle biochar incorporated diet (T3) demonstrated superior performance as it significantly (p<0.05) improved the weight gain (24.51±0.12 g), specific growth rate (1.39±0.00 % day−1), protein efficiency ratio (1.73±0.02 %), and reduced feed conversion ratio (1.60±0.01). The total serum protein in the haemolymph of the shrimps for all the dietary biochar treatments differed significantly (p<0.05) from the control. The T1, T2, and T3 groups showed the highest whole-body crude protein content; contrary to this, the lowest amount of whole-body crude protein was observed in the control. In addition, the dietary biochar significantly influenced the digestive enzymatic activity of shrimp. The hepatopancreatic AST and ALT activities of different biochar-fed groups were significantly (p < 0.05) higher than the C group. On the other hand, dietary biochar treatments did not significantly (p > 0.05) influence the SOD of the gill, muscle, and catalase activity of the hepatopancreas, gill, and muscle in shrimp. Overall, the three different dietary biochar supplementations in the diet of Penaeus vannamei seem to be an effective way to culture it intensively, in addition to significantly reducing various stress responses.

Groundwater modeling and estimation of the safe pumping rate for the sustainable use of groundwater resources in Kombolcha town, upper Borkena watershed, Ethiopia

ABSTRACT The rate of groundwater extraction is increasing due to population growth. Balancing pumping rates with natural recharge is necessary for sustainable use. The safe groundwater pumping rate was determined using the groundwater model ModelMuse. To determine the safe pumping rate, 39 borehole data points were gathered and adjusted for 4, 8, and 12 h of pumping scenarios for 50 years in a steady-state pumping condition. The recharge rates in the study area were calculated using four empirical approaches in addition to the water balance method. Of the four empirical methods, the water balance technique provided the most accurate estimates of groundwater recharge, with an estimated average recharge rate of 176.75 mm per year. The ModelMuse model water balance report demonstrated that there was positive storage for all boreholes to be pumped simultaneously under 4- and 8-h pumping rate scenarios, but that there would be a significant drawdown under 12-h pumping from the stress period of 2039–2065, and the summation of inflow and outflow would become negative, indicating that the withdrawal rate is greater than the recharge rate. Thus, the safe pumping rate for Borkena groundwater was calculated to be 975 L/s in 8-h pumping rate scenarios.

Assessing groundwater behavior and future trends in the Ardabil Aquifer: A comparative study of groundwater modeling system and categorical gradient boosting hybrid model

Rapid population growth and rising demand have led to increased groundwater extraction, underscoring the importance of effective water resource management. While groundwater models are practical tools, their reliance on extensive hydrogeological and hydrological data can pose challenges when such data is unavailable or inaccessible. In this study, two modeling approaches were employed for the prediction and characterization of groundwater behavior in Ardabil Plain from October 2010 to March 2021. Initially, groundwater behavior was modeled using Modflow. Subsequently, the groundwater behavior was modeled within the same time frame using the hybrid CatBoost-AOA model. Groundwater levels were then determined using these two models until the year 2031. The CatBoost-AOA hybrid method showed the highest agreement (correlation coefficient: 0.9977). Modflow and CatBoost models predicted a decline of 0.77 and 0.85 m, respectively, until 2031. This study aims to guide sustainable development planning, with CatBoost-AOA providing a simplified and efficient alternative for accurately forecasting groundwater fluctuations.

Groundwater Salinisation by Irrigation Practices in More Arid Regions

Groundwater Salinisation by Irrigation Practices in More Arid Regions