Articoli di riviste: "Groundwater Mathematical models"

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Abdullayev, A. A., M. Hidoyatova e B. A. Kuralov. "About one differential model of dynamics of groundwater". E3S Web of Conferences 401 (2023): 02017. http://dx.doi.org/10.1051/e3sconf/202340102017.

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When modeling the flow of groundwater and streams together, two different approaches are used, using hydraulic and hydrological models as channel flow models. The former is based on mathematical equations of water movement in open channels. In contrast, the latter is based on simplified empirical and semi-empirical relationships between the hydraulic characteristics of watercourses. In both cases, the watercourse is an internal boundary for the groundwater flow - otherwise, it is advisable to model it as a body of water. The groundwater model can be a scale model or an electrical model of the state of the groundwater or an aquifer. Groundwater models are used to represent the natural flow of groundwater in an environment. Some groundwater models include aspects of groundwater quality. Such groundwater models attempt to predict the fate and movement of a chemical in natural, urban, or hypothetical scenarios. Groundwater models can be used to predict the impact of hydrological changes on aquifer behavior and are often referred to as groundwater simulation models. Also, groundwater models are currently being used in various water management plans for urban areas. Because calculations in mathematical groundwater models are based on groundwater flow equations, which are differential equations that can often only be solved by approximate methods using numerical analysis, these models are also referred to as mathematical, numerical, or computational groundwater models.

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Fowler, A. C., e C. G. Noon. "Mathematical models of compaction, consolidation and regional groundwater flow". Geophysical Journal International 136, n. 1 (1 gennaio 1999): 251–60. http://dx.doi.org/10.1046/j.1365-246x.1999.00717.x.

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Emikh, V. N. "Mathematical models of groundwater flow with a horizontal drain". Water Resources 35, n. 2 (marzo 2008): 205–11. http://dx.doi.org/10.1134/s0097807808020097.

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Hadžić, E., N. Lazović e A. Mulaomerović-Šeta. "Application of Mathematical Models in Defining Optimal Groundwater Yield". Procedia Environmental Sciences 25 (2015): 112–19. http://dx.doi.org/10.1016/j.proenv.2015.04.016.

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Solodovnikov, Denis, Stanislav Shinkarenko, Nikolai Vishnyakov e Natalya Khavanskaya. "Groundwater of River Floodplains – Intra-Annual Dynamics and Mathematical Models". Natural Systems and Resources, n. 2 (febbraio 2020): 54–63. http://dx.doi.org/10.15688/nsr.jvolsu.2019.2.7.

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The doctrine of natural geographical zoning is a traditional and well-developed field of physical geography. Zonal landscapes of the planet are perfectly classified and have clear diagnostic signs. The situation is different with intrazonal landscapes. The criteria for their differentiation are not so obvious. Despite the objective differences in the landscapes of floodplains of forest and steppe natural zones, the principles of their differentiation and classification have not yet been eveloped. The most important factor in the functioning of floodplain landscapes is the seasonal dynamics of groundwater. The annual series of observations allows to graphically display this dynamic in the form of combined transverse profiles of river floodplains, reflecting the relief, the level of surface waters and the changing position of the upper boundary of groundwater. Two-dimensional figures on the profiles are subjected to mathematical processing and allow to develop mathematical models of annual groundwater dynamics. Such models can serve as a basis for classification of intrazonal landscapes of river floodplains. The idea of the study is to try to give an objective picture of natural processes in the floodplains of rivers of the arid zone, based on accurate quantitative characteristics comparable to each other. For mathematical processing, we selected field experimental plots, allowing to obtain a representative profile of the relief and the position of the groundwater mirror during the year. Two-year observations of groundwater have provided a comprehensive picture of their dynamics and relationships to the surface water regime. The results of this work were reflected graphically in the form of profiles. At the next stage, with the help of the Verner Graphical Analysis program, adequate mathematical models describing the process were selected. Verification of models showed a high degree of their reliability. The next stage of the work should be the comparative characteristics of floodplains of rivers of different natural zones and regions, based on the proposed approach. In combination with other criteria (humus content in soils, species composition of tree and shrub vegetation), this will make it possible to differentiate the landscapes of river floodplains and develop schemes for zoning intrazonal landscapes.

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Afrifa, Stephen, Tao Zhang, Peter Appiahene e Vijayakumar Varadarajan. "Mathematical and Machine Learning Models for Groundwater Level Changes: A Systematic Review and Bibliographic Analysis". Future Internet 14, n. 9 (30 agosto 2022): 259. http://dx.doi.org/10.3390/fi14090259.

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With the effects of climate change such as increasing heat, higher rainfall, and more recurrent extreme weather events including storms and floods, a unique approach to studying the effects of climatic elements on groundwater level variations is required. These unique approaches will help people make better decisions. Researchers and stakeholders can attain these goals if they become familiar with current machine learning and mathematical model approaches to predicting groundwater level changes. However, descriptions of machine learning and mathematical model approaches for forecasting groundwater level changes are lacking. This study picked 117 papers from the Scopus scholarly database to address this knowledge gap. In a systematic review, the publications were examined using quantitative and qualitative approaches, and the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) was chosen as the reporting format. Machine learning and mathematical model techniques have made significant contributions to predicting groundwater level changes, according to the study. However, the domain is skewed because machine learning has been more popular in recent years, with random forest (RF) methods dominating, followed by the methods of support vector machine (SVM) and artificial neural network (ANN). Machine learning ensembles have also been found to help with aspects of computational complexity, such as performance and training times. Furthermore, compared to mathematical model techniques, machine learning approaches achieve higher accuracies, according to our research. As a result, it is advised that academics employ new machine learning techniques while also considering mathematical model approaches to predicting groundwater level changes.

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Discacciati, Marco, Edie Miglio e Alfio Quarteroni. "Mathematical and numerical models for coupling surface and groundwater flows". Applied Numerical Mathematics 43, n. 1-2 (ottobre 2002): 57–74. http://dx.doi.org/10.1016/s0168-9274(02)00125-3.

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Hurley, G. A. "The prediction of groundwater levels using computer based mathematical models". Geological Society, London, Engineering Geology Special Publications 3, n. 1 (1986): 321–25. http://dx.doi.org/10.1144/gsl.eng.1986.003.01.38.

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Sierikova, Olena, Volodymyr Koloskov e Elena Strelnikova. "The groundwater level changing processes modeling in 2D and 3D formulation". Acta Periodica Technologica, n. 53 (2022): 36–47. http://dx.doi.org/10.2298/apt2253036s.

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The objective of this study was to develop a mathematical model to determine the tendency of the groundwater level changes under the influence of external factors to prevent environmentally hazardous impacts and emergency situations. Mathematical methods (analytical solution of differential filtration equations involved the computer program Maple) - for creation the groundwater level changes model, methods of ecological and economic assessment and comparative analysis - for the identification of groundwater level impact important factors and groundwater level impact on the environment, balance method - for assessing the groundwater level changes. The mathematical model in 2D formulation works from any value of the initial groundwater level. The value of groundwater level changing at constant evapotranspiration has been obtained, which has been visualized by calculations for limited areas of the Kharkiv territory. Three-dimensional modelling of groundwater level changing in contrast to two-dimensional allows to take into account the dependence of evapotranspiration on the presence of artificial coverings on the soil surface, which are located unevenly and have different filtration coefficients, which causes corresponding groundwater level changes of urban areas. The nature of groundwater level changes under the influence of external factors has been determined. The necessity to create three-dimensional mathematical models to describe groundwater level changes and improve forecasts of their changes have been identified. A three-dimensional mathematical model of urban groundwater level changes, such as atmospheric water infiltration, additional groundwater replenishment, transpiration, evaporation, evapotranspiration, and groundwater abstraction has been developed. The boundary conditions of the three-dimensional mathematical model have been formulated.

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Liu, Baoling, Gang Li, Hong You, Mingrui Sui e Shutao Wang. "Evaluation of dynamic groundwater quality simulation based on Cloud-GIS: a case study in Harbin urban area, China". Water Supply 14, n. 6 (28 giugno 2014): 1095–104. http://dx.doi.org/10.2166/ws.2014.070.

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This paper consists of two parts. The first part addresses the joint modeling of both spatial and temporal elements to perform dynamic evaluation of groundwater quality. In this part, a grey prediction method was used to predict missing values and then, on the basis of an entropy-weighting method, to build a dynamic weight model which continually changes with time; finally, a fuzzy evaluation method was used to evaluate groundwater quality. MATLAB was used to integrate these mathematical models. The second part describes the construction of a dynamic simulation platform which integrated mathematical models, a property database, and a spatial database, with secondary developments in geographic information system (GIS) and cloud-based simulation technology. All calculation steps and simulation programs were carried out on the simulation platform. The results indicated the grade of groundwater quality between II and IV. Groundwater quality gradually rose in the first and fourth quarters, but continually decreased in the second and third quarters. The lowest groundwater-quality value for the entire year appeared in October. This result also illustrates that turning points in groundwater quality appear when groundwater levels increase or decrease along rivers.

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Fehér, Zsolt Zoltán. "A Spatiotemporal Stochastic Framework Of Groundwater Fluctuation Analysis On The South - Eastern Part Of The Great Hungarian Plain". Journal of Environmental Geography 8, n. 3-4 (1 dicembre 2015): 41–52. http://dx.doi.org/10.1515/jengeo-2015-0011.

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Abstract The current study was performed on a Hungarian area where the groundwater has been highly affected in the past 40 years by climate change. The stochastic estimation framework of groundwater as a spatiotemporally varying dynamic phenomenon is proposed. The probabilistic estimation of the water depth is performed as a joint realization of spatially correlated hydrographs, where parametric temporal trend models are fitted to the measured time series thereafter regionalized in space. Two types of trend models are evaluated. Due to its simplicity the purely mathematical trend can be used to analyze long-term groundwater trends, the average water fluctuation range and to determine the most probable date of peak groundwater level. The one which takes advantage of the knowledge of expected groundwater changes, clearly over performed the purely mathematical model, and it is selected for the construction of a spatiotemporal trend. Model fitting error values are considered as a set of stochastic time series which expresses short-term anomalies of the groundwater, and they are modelled as joint space-time distribution. The resulting spatiotemporal residual field is added to the trend field, thus resulting 125 simulated realizations, which are evaluated probabilistically. The high number of joint spatiotemporal realizations provides alternative groundwater datasets as boundary conditions for a wide variety of environmental models, while the presented procedure behaves more robust over non-complete datasets.

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Yusupov, R. A., Sh S. Axrolov, N. M. Mirzanova e A. N. Nasiriddinov. "MATHEMATICAL MODELS OF GEOFILTRRATION AND GEOMIGRATION IN POROUS MEDIA WITH FRACTAL STRUCTURE". TECHNICAL SCIENCES 6, n. 3 (30 giugno 2020): 21–27. http://dx.doi.org/10.26739/2181-9696-2020-6-4.

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In this study 2-D linear models are coming from generalised, Boussinesq eqution describing geofiltration in soils with fractal structures are presented. In this study are presented too mathematical models geomigration of contaminations with groundwater in classical way and in soils with fractal structures.

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Yusupov, R. A., Sh S. Axrolov, N. M. Mirzanova e A. N. Nasiriddinov. "MATHEMATICAL MODELS OF GEOFILTRRATION AND GEOMIGRATION IN POROUS MEDIA WITH FRACTAL STRUCTURE". TECHNICAL SCIENCES 5, n. 3 (30 maggio 2020): 39–45. http://dx.doi.org/10.26739/2181-9696-2020-5-6.

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In this study 2-D linear models are coming from generalised, Boussinesq eqution describing geofiltration in soils with fractal structures are presented. In this study are presented too mathematical models geomigration of contaminations with groundwater in classical way and in soils with fractal structures

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Yusupov, R. A., S. Axrolov, N. M. Mirzanova e A. N. Nasiriddinov. "MATHEMATICAL MODELS OF GEOFILTRRATION AND GEOMIGRATION IN POROUS MEDIA WITH FRACTAL STRUCTURE". PHYSICAL AND MATHEMATICAL SCIENCES 4, n. 1 (30 aprile 2020): 40–46. http://dx.doi.org/10.26739/2181-0656-2020-4-5.

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In this study 2-D linear models are coming from generalised, Boussinesq eqution describing geofiltration in soils with fractal structures are presented. In this study are presented too mathematical models geomigration of contaminations with groundwater in classical way and in soils with fractal structures

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Yu, Furong, Wenxi Lu, Ping Li, Xin Xin e Jun Li. "Dynamic optimal control for groundwater optimization management with covariates". Journal of Hydroinformatics 14, n. 2 (30 giugno 2011): 386–94. http://dx.doi.org/10.2166/hydro.2011.076.

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It is well known that obtaining optimal solutions for groundwater management models with covariates is a challenging task, especially for dynamic planning and management. Here, a theory and method of dealing with mutual-feed joint variation in groundwater management models is described. Specifically, an equation expressing the inherent connection between covariates and groundwater level was developed. This equation was integrated into a mathematical simulation model of groundwater, after which a groundwater dynamic optimization management model with covariates was constructed using the state transition equation method and solved with differential dynamic programming algorithms. Finally, the above theory and method were applied to a hypothetical groundwater system. For the same groundwater system, a groundwater management model with covariates was developed and the results of the two optimization methods were found to be nearly identical, which validated the theory and methods put forth here.

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Moeeni, Saad, Naved Ahsan e Mohammad Sharif. "Simulation of Groundwater levels in River basin using MODFLOW". Ecology, Environment and Conservation 29, n. 01 (2023): 81–85. http://dx.doi.org/10.53550/eec.2023.v29i01.011.

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MODFLOW is a groundwater modelling program. It can be compiled according to the practical applications. Groundwater flow models are used to calculate the rate and direction of movement of groundwater through aquifers. The outputs from model simulation are the groundwater flow and hydraulic heads which are in equilibrium with the specified hydrogeological conditions (i.e. hydrologic boundaries, hydrogeological framework, initial and transient conditions, hydraulic properties and sources) demarcated for the modelled area. Groundwater models perform an important role in the management and development of groundwater resources. This paper presents the results of a mathematical groundwater model developed for the Banda districts which is part of Yamuna River basin. For this purpose, groundwater modelling software (GMS) MODFLOW was used. The model results display that the computed values are in goodfitness of the measure data, which indicate the model is reliable.

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Kroepsch, Adrianne C. "Groundwater Modeling and Governance: Contesting and Building (Sub)Surface Worlds in Colorado’s Northern San Juan Basin". Engaging Science, Technology, and Society 4 (1 marzo 2018): 43. http://dx.doi.org/10.17351/ests2018.208.

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As groundwater use has surged globally and computing power has grown, groundwater modeling has become a regular feature of subsurface-oriented governance. Our improved ability to “see” underground with models has not, however, generated epistemic consensus on the inner workings of subsurface systems. Here, I ask how and why that is the case. I pursue this line of inquiry in the context of groundwater governance in the American West. Specifically, I trace a decade of groundwater modeling at the heart of a protracted and legally influential groundwater dispute in the state of Colorado to show how models served as mathematical spaces for competing subsurface stakeholders to test and contest opposing visions of groundwater flows, rights, and responsibilities. Drawing from the Science & Technology Studies literature on global climate modeling, I argue that groundwater models are more than simulations of subsurface systems; they are tools of “world building” that embed, enact, and also circumscribe subsurface politics.

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Boyraz, Uğur, e Cevza Melek Kazezyılmaz-Alhan. "Solutions for groundwater flow with sloping stream boundary: analytical, numerical and experimental models". Hydrology Research 49, n. 4 (9 giugno 2017): 1120–30. http://dx.doi.org/10.2166/nh.2017.264.

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Abstract Protecting groundwater resources plays an important role in watershed management. For this purpose, studies on groundwater flow dynamics incorporating surface water–groundwater interactions have been conducted including analytical, numerical, and experimental models. In this research, a stream–aquifer system was considered to understand the physical behavior of surface water–groundwater interactions. Interactions in a stream–aquifer system were incorporated into the mathematical modeling by defining the stream head as a boundary condition for the groundwater flow equation. This boundary was chosen as a sloping stream boundary, which is an approach in representing the natural conditions of the stream and may be used to define continuous interactions between stream and aquifer. A semi-analytical solution for transient 2D groundwater flow was developed for the considered problem. Isotropic, homogeneous, and finite aquifer assumptions were made in order to define the aquifer characteristics. Then, a series of laboratory experiments was conducted to simulate this stream–aquifer system. Finally, a numerical model was developed by using Visual MODFLOW to verify analytical and experimental results. Numerical results matched with both analytical solutions and the experimental observations.

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Ali, Arkan, Abbas Hussein, Kareem Abood e Najah Al Maimuri. "Sensitivity of Infiltration Models in Rural Soils Overlying Unsteady Shallow Groundwater". Iraqi Geological Journal 56, n. 1D (30 aprile 2023): 43–57. http://dx.doi.org/10.46717/igj.56.1d.4ms-2023-4-13.

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According to the theoretical concept, the infiltration rate gradually decreases as the shallow groundwater rises to the surface of unsaturated soil regardless of the hydraulic conductivity value. It is expected to decrease to the least when the shallow groundwater level reaches the soil surface and the soil is waterlogged. For this, a deep infiltration test was conducted for four types namely as; (soil no.1: sandy clay, soils no.2, 3 and 4: clayey sand) in the laboratory by means of the infiltration box, in which the amount of infiltration is measured with the hypothetical depth of shallow groundwater. In addition, a site test of infiltration was carried out on a sandy clay field soil in the Abu-Gharaq area, west of Babylon Governorate, Iraq, by means of an infiltration square trench with dimensions of 3 m * 3 m * 2.5 m depth. The trench is connected to a drainage ditch by pipes of 3 inches in diameter for removing excess water to maintain constant artificial groundwater. The results showed that the amount of accumulated infiltration depth increases with increasing shallow groundwater depth and k of unsaturated soil zone. The mathematical relationship between them is linear with a correlation coefficient of more than 0.99. Soil texture did not affect the amount of penetration as much as the depth of groundwater.

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Das, Pintu, Sultana Begam e Mritunjay Kumar Singh. "Mathematical modeling of groundwater contamination with varying velocity field". Journal of Hydrology and Hydromechanics 65, n. 2 (1 giugno 2017): 192–204. http://dx.doi.org/10.1515/johh-2017-0013.

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Abstract In this study, analytical models for predicting groundwater contamination in isotropic and homogeneous porous formations are derived. The impact of dispersion and diffusion coefficients is included in the solution of the advection-dispersion equation (ADE), subjected to transient (time-dependent) boundary conditions at the origin. A retardation factor and zero-order production terms are included in the ADE. Analytical solutions are obtained using the Laplace Integral Transform Technique (LITT) and the concept of linear isotherm. For illustration, analytical solutions for linearly space- and time-dependent hydrodynamic dispersion coefficients along with molecular diffusion coefficients are presented. Analytical solutions are explored for the Peclet number. Numerical solutions are obtained by explicit finite difference methods and are compared with analytical solutions. Numerical results are analysed for different types of geological porous formations i.e., aquifer and aquitard. The accuracy of results is evaluated by the root mean square error (RMSE).

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de Rooij, G. H. "Is the groundwater reservoir linear? A mathematical analysis of two limiting cases". Hydrology and Earth System Sciences Discussions 11, n. 1 (6 gennaio 2014): 83–108. http://dx.doi.org/10.5194/hessd-11-83-2014.

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Abstract. Storage–discharge relationships of the groundwater reservoirs of several catchments in a temperate-humid climate were reported in the literature to be seemingly non-linear. Once recharge was adequately accounted for during model calibration they turned out to be linear. The question was posed if this linearity was a fundamental property of groundwater reservoirs in general. A mathematical analysis based on analytical solutions for several cases involving parallel flow in horizontal aquifers shows that this is not the case when the surface water level is close to the aquifer bottom. When the aquifer is of constant thickness, linear-reservoir behaviour arises when the forcings remain constant for a sufficiently long time. This can range from a few weeks for aquifers with a dense drainage network of streams or ditches to years or centuries for large aquifers drained by rivers many kilometers apart. The characteristic time of the groundwater reservoir depends on whether or not the aquifer is leaky and recharge is non-zero. It is concluded that groundwater reservoirs can only be linear if their thickness can be assumed independent of the hydraulic head, and if they have a dense drainage network. Even then, they behave non-linearly up to several weeks after a change in recharge. Models that conceptualize the catchment as a configuration of coupled reservoirs will normally assign the groundwater discharge surplus generated because of the initially non-linear behaviour of the groundwater to their fast-responding reservoirs, thereby exaggerating the importance of fast-responding flow routes in a catchment.

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Smith, W. R., G. C. Wake, J. E. McIntosh, R. P. McIntosh, M. Pettigrew e R. Kao. "Mathematical analysis of perifusion data: models predicting elution concentration". American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 261, n. 1 (1 luglio 1991): R247—R256. http://dx.doi.org/10.1152/ajpregu.1991.261.1.r247.

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System models are constructed and analyzed for combined convective flow and for dispersion in distorting concentrations of a chemical signal as it passes through a packed column. We derive general analytical solutions for these models. The results have applications to analyses such as in biological experiments involving hormonal stimulation of perifused cells, elution chromatography, adsorption columns, and studies of groundwater flow. The models reveal that the column distorts an incoming signal (such as a change in solute concentration in the flowing liquid) at the inlet. This distortion is greatest at low values of the Peclet number of the flow and is small at larger values. We explore the effects of the approximations inherent in the mathematical models of the system. Specification of the boundary conditions of the problem are shown to be particularly important. With the use of incorrect models, it is possible to obtain accurate interpolations to data obtained from perfusion experiments. However, the parameters derived (in particular the dispersion constant and the peak concentration of a solute concentration pulse) may be considerably in error. This may lead to errors when these parameter estimates are used to predict results in other experimental situations.

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Gu, Lei Lei, Jing Li Shao, Yue Sun e Yun Zhang Zhao. "Groundwater Flow Simulation and Resource Evaluation of the Affected Zone along the Yellow River (Henan Section)". Advanced Materials Research 610-613 (dicembre 2012): 2713–18. http://dx.doi.org/10.4028/www.scientific.net/amr.610-613.2713.

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The purpose of this paper is to build a three-dimensional groundwater flow model of the affected zone along the Yellow River, and to conduct equilibrium analysis and resource evaluation to the groundwater of the research area according to the simulation results. In the beginning, the groundwater flow numerical simulation model (1999.1-2009.12) is established and verified through the GMS software on the basis of the establishment of hydrogeological conceptual and mathematical models. Results of the simulation model show that the perennial average of the resources of shallow groundwater recharge is 29.32×108m3/a, the average recharge modulus is 22.35×104m3/km2•a and the safe yield of groundwater resource is 27.04×108m3/a.

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Kvartenko, Oleksandr, e Igor Prysiazhniuk. "FORECASTING THE GROUNDWATER TREATMENT PROCESS IN A BIOREACTOR USING FERROBACTERIA". Problems of Water supply, Sewerage and Hydraulic, n. 37 (12 dicembre 2021): 22–28. http://dx.doi.org/10.32347/2524-0021.2021.37.22-28.

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The monitoring of water quality parameters in 90 settlements of eight regions of Ukraine made it possible to state that groundwater is a complex multicomponent system. Existing deironing stations using simplified aeration-filtration technology are not able to remove Fe (II) compounds from water in the presence of humic complexes. Therefore, in modern conditions, the urgent task is to intensify their work through the introduction of new technologies, including biotechnology with the development of appropriate mathematical models. It is shown that much less attention was paid to modeling the kinetics of groundwater treatment processes in bioreactors than to traditional physicochemical methods, for which modern mathematical models were developed. The aim of the work is to develop a mathematical model of the kinetics of the process of groundwater treatment in bioreactors. The mathematical model is represented by the Cauchy problem for a nonlinear system of differential equations in partial derivatives of the first order. The system of the Cauchy problem consists of five equations with five unknown functions, which describe the distribution the concentration of ferrum cations, bacteria and the matrix structures in two phases (movable and immobilized) both in space and time. The inverse influence of the characteristics of the process, in particular, the concentration of matrix structures in the inter-pore space, as well as characteristics of the medium with the help of coefficients of mass exchange and porosity, were taken into account. The model allows determining the optimum operation time of a bioreactor between washings

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Παναγόπουλος, A., E. Δρακοπούλου e V. Περλέρος. "APPLICATION OF THE MATHEMATICAL MODEL MODFLOW ON A KARSTIC AQUIFER: THE CASE OF VIOTIKOS KIFISOS BASIN". Bulletin of the Geological Society of Greece 36, n. 4 (1 gennaio 2004): 2021. http://dx.doi.org/10.12681/bgsg.16701.

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MODFLOW is a very well verified code of mathematical modeling for simulation of saturated groundwater flow in porous medium. Groundwater flow simulation in discontinuity media (i.e. media characterized by dominance of secondary and tertiary porosity as opposed to primary porosity), such as karstic aquifers, utilizing specialized models is problematic. Due to existing impedes the use of the conventional model MODFLOW was attempted for the simulation of the karstic system of the Viotikos Kifisos river aiming predominantly at assessing the potential, restrictions, particularities and conditions under which such a modelling code could be implemented, especially when relatively restricted volume of raw data is available. Compilation and calibration of the model suggest that MODFLOW may in general be implemented and can provide useful results. As in every mathematical model, knowledge of the assumptions made and the intrinsic restrictions involved is required, along with in-depth evaluation of its capabilities. The mathematical model of Viotikos Kifisos basin forms a valuable tool for management of its water resources and study of regional groundwater evolution.

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Tahershamsi, Ahmad, Atabak Feizi e Siavash Molaei. "Modeling Groundwater Surface by MODFLOW Math Code and Geostatistical Method". Civil Engineering Journal 4, n. 4 (3 maggio 2018): 812. http://dx.doi.org/10.28991/cej-0309135.

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Simulation of groundwater flow by mathematical model can be used for developing aquifer balance element analysis scenarios, explaining conditions of droughts, definition of prohibitive extraction policies and analyzing the qualitative models. In this study, the development of a quantitative model in terms of the main parameters affecting on the water surface changes has been performed for the Ardebil plain (located in NW of Iran). Accordingly, a comprehensive processing of raw data sets has been carried-out by means of MODFLOW mathematical model. Also to simulate the groundwater surface changes in the mentioned plain, the geo-statistical method has been used. Results indicate that the mathematical model used in the aquifer balance simulation for the Ardebil plain has approximately 2% relative normal root-mean-square error (NRMSE). This small NRSMSE confirms the model accuracy for the Ardebil plain using the calibration data. Moreover, comparing the results of this method and the ones obtained by mathematical model performed by examining some error criteria like RMSE, Mean, ASE and MS, it is found that the accuracy of the mathematical model is higher than the geostatistical method and the main reason for this is the distribution of uncertainty in a few available piezometric points in the geostatistical method.

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Yakirevich, Alexander. "Water Flow, Solute and Heat Transfer in Groundwater". Water 12, n. 7 (28 giugno 2020): 1851. http://dx.doi.org/10.3390/w12071851.

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Groundwater is an essential and vital water resource for drinking water production, agricultural irrigation, and industrial processes. The better understanding of physical and chemical processes in aquifers enables more reliable decisions and reduces the investments concerning water management. This Special Issue on “Water Flow, Solute and Heat Transfer in Groundwater” of Water focuses on the recent advances in groundwater dynamics. In this editorial, we introduce 12 high-quality papers that cover a wide range of issues on different aspects related to groundwater: protection from contamination, recharge, heat transfer, hydraulic parameters estimation, well hydraulics, microbial community, colloid transport, and mathematical models. By presenting this integrative volume, we aim to transfer knowledge to hydrologists, hydraulic engineers, and water resources planners who are engaged in the sustainable development of groundwater resources.

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Jha, Madan K., Richard C. Peralta e Sasmita Sahoo. "Simulation-Optimization for Conjunctive Water Resources Management and Optimal Crop Planning in Kushabhadra-Bhargavi River Delta of Eastern India". International Journal of Environmental Research and Public Health 17, n. 10 (18 maggio 2020): 3521. http://dx.doi.org/10.3390/ijerph17103521.

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Water resources sustainability is a worldwide concern because of climate variability, growing population, and excessive groundwater exploitation in order to meet freshwater demand. Addressing these conflicting challenges sometimes can be aided by using both simulation and mathematical optimization tools. This study combines a groundwater-flow simulation model and two optimization models to develop optimal reconnaissance-level water management strategies. For a given set of hydrologic and management constraints, both of the optimization models are applied to part of the Mahanadi River basin groundwater system, which is an important source of water supply in Odisha State, India. The first optimization model employs a calibrated groundwater simulation model (MODFLOW-2005, the U.S. Geological Survey modular ground-water model) within the Simulation-Optimization MOdeling System (SOMOS) module number 1 (SOMO1) to estimate maximum permissible groundwater extraction, subject to suitable constraints that protect the aquifer from seawater intrusion. The second optimization model uses linear programming optimization to: (a) optimize conjunctive allocation of surface water and groundwater and (b) to determine a cropping pattern that maximizes net annual returns from crop yields, without causing seawater intrusion. Together, the optimization models consider the weather seasons, and the suitability and variability of existing cultivable land, crops, and the hydrogeologic system better than the models that do not employ the distributed maximum groundwater pumping rates that will not induce seawater intrusion. The optimization outcomes suggest that minimizing agricultural rice cultivation (especially during the non-monsoon season) and increasing crop diversification would improve farmers’ livelihoods and aid sustainable use of water resources.

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Sedykh, I. A. "FORECASTING THE GROUNDWATER LEVEL OF CEMENT RAW MATERIALS DEPOSIT BASED ON DYNAMIC NEIGHBORHOOD MODELS". Vestnik of Don State Technical University 18, n. 3 (29 settembre 2018): 326–32. http://dx.doi.org/10.23947/1992-5980-2018-18-3-326-332.

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Introduction. The development of a mathematical model for the groundwater level of a deposit of cement raw materials located in the Zadonian-Yelets aquifer, which is the principal domestic water supply source for the city of Lipetsk, is considered. Therefore, it is necessary to provide ongoing monitoring and to have the possibility to predict the water level under the field development. The work objectives are the identification and study of a dynamic neighborhood model with variable hierarchical neighborhoods of the groundwater level that enables to adequately predict value of the water level in the examined wells.Materials and Methods. The definition of a dynamic neighborhood model with variable hierarchical neighborhoods is given, differing by time-varying double-level neighborhood communications between the first- and second-level nodes. At each next discrete instant of time, the neighborhood model nodes change their state under the influence of the online parameters and node states included in their neighborhood. As a subcase, we consider a model with line state recalculation functions. Parametric identification of the dynamic neighborhood model consists in finding the system parameters for each second-level node, and is based on the ordinary least squares.Research Results. A linear dynamic neighborhood model with variable hierarchical neighborhoods for predicting the groundwater level in a cement raw material deposit located in the Zadonian-Yelets aquifer is developed. The software using C++ is developed for the parametric identification and simulation of the functioning of the dynamic neighborhood model under consideration. It enables to determine parameters of the node state recalculation functions for a given structure, and also to predict the model behavior in the operation process. A hierarchical structure is given, and a parametric identification of the linear dynamic neighborhood model of the groundwater level is carried out. After the parametric identification on the teaching data selection, the mathematical model is checked on the test sample.Discussion and Conclusions. The obtained average ratio errors of the identification and forecast suggest the developed model validity and enable to recommend it for predicting the underground water level of a cement raw materials deposit.

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Avlakulov, M., I. E. Kodirov e Sh Sh Faiziev. "Mass transfer processes in a heterogeneous medium occurring in the aeration zone during infiltration of surface waters". E3S Web of Conferences 411 (2023): 02022. http://dx.doi.org/10.1051/e3sconf/202341102022.

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The article discusses issues related to the creation of mathematical models that are used to solve various problems arising in the hydrological and hydrogeological cycles. The analysis of the mathematical correctness of the solved problems, which correspond to the initial boundary conditions, is given. When studying the phenomena associated with the exchange of mass between surface and groundwater flows, it becomes necessary to study several issues in order to hydraulically substantiate the models being developed and their numerical implementation. This circumstance is of great importance when creating a picture of the interacting processes of runoff and water infiltration.

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Aniszewski, A. "Incorporation of advection and adsorption in modeling ground water quality". Water Supply 1, n. 2 (1 marzo 2001): 231–35. http://dx.doi.org/10.2166/ws.2001.0042.

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A one-dimensional model of groundwater flow, incorporating advection and adsorption of conservative pollutants has been presented. Based on earlier laboratory experiments on physical models and adopting the numerical solution of the presented mathematical model, the adsorption parameters k1 and n have been calculated for a non-linear function describing this process. Empirical relationships for the adsorption parameters characteristic of the aquifer and the ground water flow have been developed. These relationships should allow for better forecasting and estimation of groundwater quality at the intake.

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Vinda, Ram Raj, Raja Ram Yadava e Naveen Kumar. "Uniform Horizontal Groundwater Flow against Dispersion in a Shallow Aquifer: Two Analytical Models". Hydrology Research 23, n. 1 (1 febbraio 1992): 1–12. http://dx.doi.org/10.2166/nh.1992.0001.

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Analytical solutions converging rapidly at large and small values of times have been obtained for two mathematical models which describe the concentration distribution of a non reactive pollutant from a point source against the flow in a horizontal cross-section of a finite saturated shallow aquifer possessing uniform horizontal groundwater flow. Zero concentration or the conditions in which the flux across the extreme boundaries are proportional to the respective flow components are applied. The effects of flow and dispersion on concentration distribution are also discussed.

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Krusteva, Ekaterina D., Stefan Y. Radoslavov e Zdravko I. Diankov. "Modelling the Seepage of Groundwater: Application of the Viscous Analogy and Numerical Methods". Applied Rheology 9, n. 4 (1 agosto 1999): 165–71. http://dx.doi.org/10.1515/arh-2009-0012.

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Abstract The application of the viscous analogy, known as the Hele-Show model, for seepage investigation is demonstrated in the paper. The changes in the viscous properties of the model fluid (glycerine) resulting from the changes of the atmospheric conditions - temperature and humidity, have been taken under consideration as factors influencing the flow discharge in the model. A method has been substantiated for the exact quantitative comparison of discharges obtained under different boundary conditions of the seepage process using parallel rheological measurements of the model fluid. The results from the viscous and mathematical models are compared for a particular two-dimensional seepage process - the operation of a horizontal drainage. The complete coincidence of these results, proves the good grounds of the method as well as its applicability as a test method for the development of mathematical models.

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Rudenko, Yu F., V. M. Shestopalov, Iu A. Negoda e O. V. Gural. "ON THE RATIONAL USE OF EXPLOITABLE DRINKING GROUNDWATER RESERVES FOR WATER SUPPLY TO THE CITY OF KYIV". Geological Journal, n. 4 (28 dicembre 2021): 29–55. http://dx.doi.org/10.30836/igs.1025-6814.2021.4.240101.

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The influence of anthropogenic load within the Kyiv field of drinking groundwater has resulted in deformation of the water exchange structure and pattern. The main anthropogenic factors affecting water exchange include groundwater intake structures, reservoirs, as well as urban-industrial agglomerations. The paper presents a critical analysis of the previous hydrogeological models of the groundwater field under study, taking into account their shortcomings and using the most realistic solutions. New up-to-date hydrogeological model of the study area has been created. Simulation modelling was performed to determine the effects of hydrogeological parameters changes on the groundwater level position. Epignostic modelling allowed us to specify transmissivity of aquifers, specific permeability of confining beds and natural groundwater recharge, as well as to prove functional correspondence of the created model to naturalanthropogenic conditions. Exploitable reserves of drinking groundwater for the city of Kyiv were reassessed according to the current request of PJSC “AK” Kyivodokanal” and the potential of groundwater withdrawal was shown. Reserves calculated by method of mathematical modelling were approved by the State Committee of Reserves of Ukraine.

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Kimball, Colin E. "Evaluating Groundwater Pollution Susceptibility of Dust Suppressants and Roadbed Stabilizers: Case Study of a Petroleum-Based Product". Transportation Research Record: Journal of the Transportation Research Board 1589, n. 1 (gennaio 1997): 64–69. http://dx.doi.org/10.3141/1589-11.

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Current environmental regulations have prompted regulatory officials, users, and manufacturers of roadbed stabilizers and dust suppressants to evaluate the environmental impact of these products to ensure that human health and the environment are not compromised through their use. Because roadbed stabilizers and dust suppressants are inherently designed to prevent dust emissions and erosion, this study focuses on evaluating the groundwater pollution susceptibility of roadbed stabilizers and dust suppressants. Current techniques used in evaluating hazardous waste sites to estimate the fate and transport of constituents in the subsurface are useful for evaluating roadbed stabilizers and dust suppressants. Chemical properties of roadbed stabilizers and dust suppressants along with generic soil property parameters can be incorporated into screening-level mathematical models to estimate constituent target-level concentrations in groundwater. These techniques were applied to a petroleum-based soil stabilizer and dust suppressant known as Pennz-Suppress D (petroleum-based product). The content of Environmental Protection Agency priority pollutants was determined by laboratory analysis. Further testing with leachate extraction methods provided additional data on leachability of the petroleum-based products under assumed worst-case conditions. Mathematical modeling was used to qualify the results. Groundwater pollution susceptibility results indicate a low risk for the product to adversely affect groundwater.

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Tanachaichoksirikun, Pinit, e Uma Seeboonruang. "Distributions of Groundwater Age under Climate Change of Thailand’s Lower Chao Phraya Basin". Water 12, n. 12 (10 dicembre 2020): 3474. http://dx.doi.org/10.3390/w12123474.

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Groundwater is important for daily life, because it is the largest freshwater source for domestic use and industrial consumption. Sustainable groundwater depends on many parameters: climate change is one factor, which leads to floods and droughts. Distribution of groundwater age indicates groundwater velocity, recharge rate and risk assessment. We developed transient 3D mathematical models, i.e., MODFLOW and MODPATH, to measure the distributions of groundwater age, impacted by climate change (IPSL-CM5A-MR), based on representative concentration pathways, defined in terms of atmospheric CO2 concentration, e.g., 2.6 to 8.5, for the periods 2020 to 2099. The distributions of groundwater age varied from 100 to 100,000 years, with the mean groundwater age ~11,000 years, generated by climate led change in recharge to and pumping from the groundwater. Interestingly, under increasing recharge scenarios, the mean age, in the groundwater age distribution, decreased slightly in the shallow aquifers, but increased in deep aquifers, indicating that the new water was in shallow aquifers. On the other hand, under decreasing recharge scenarios, groundwater age increased significantly, both shallow and deep aquifers, because the decrease in recharge caused longer residence times and lower velocity flows. However, the overall mean groundwater age gradually increased, because the groundwater mixed in both shallow and deep aquifers. Decreased recharge, in simulation, led to increased groundwater age; thus groundwater may become a nonrenewable groundwater. Nonrenewable groundwater should be carefully managed, because, if old groundwater is pumped, it cannot be restored, with a detriment to human life.

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TYMCHYSHYN, VASYL, e FRANK OTOO. "ARCHITECTURE OF A SOFTWARE SYSTEM FOR SOIL POLLUTION PROCESSES MODELING AS A RESULT OF DIFFUSION OF NITROGEN DIOXIDE IN SOILS AND GROUNDWATER". Herald of Khmelnytskyi National University. Technical sciences 319, n. 2 (27 aprile 2023): 351–59. http://dx.doi.org/10.31891/2307-5732-2023-319-1-351-359.

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The work proposes a software architecture that will allow simulating the processes of soil pollution due to the diffusion of nitrogen dioxide in soils and groundwater. To achieve this goal, mathematical models were used to predict the dynamics of concentrations of harmful emissions, as well as a model of diffusion of nitrogen dioxide in the soil and reservoir. The use of mathematical models will allow predicting changes in concentrations of nitrogen dioxide at a certain point of pollution. In addition, the model of diffusion of nitrogen dioxide in the soil and reservoir will help to determine the ways of the spread of pollution and its impact on the environment. Such models are based on difference equations or differential equations in partial derivatives, which allow to describe the dependence between various factors. The software architecture includes the necessary modules for entering initial conditions, performing calculations, visualizing results, and making adjustments to the model if necessary. A number of diagrams are presented that illustrate the features of interaction of system modules at the level of classes and components

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KOWALÓW, Mariusz, Marta CHRYŚCINA e Małgorzata WRÓBEL-HEN. "AN EXAMPLE OF THE APPLICATION OF A FILTRATION MODEL TO THE PREDICTION OF THE INFLUENCE OF A DEEP-FOUNDED BUILDING ON GROUNDWATER LEVEL CHANGES". Biuletyn Państwowego Instytutu Geologicznego 471 (1 ottobre 2018): 73–80. http://dx.doi.org/10.5604/01.3001.0012.5049.

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Nowadays, for economical aspect, most of large cubature objects are constructed with underground storeys or car park areas. During the planning phase, it is important to design an optimal, economical and safe dewatering system and technical solutions aimed to eliminate the influence of underground structure on groundwater levels in the neighbourhood. Mathematical modelling of groundwater filtration allows creating a prognosis of excavation dewatering process and influence of new buildings on groundwater levels in subject areas during both execution and operation of structure. The paper presents an example of groundwater filtration modelling for a shopping mall in the centre of Budapest, using SPRING software. The project includes the construction of a large building with an underground story for cars. With filtration models, it was possible to assess the changes in groundwater flow fields caused by projected structure and its excavation dewatering system and the prognosis of groundwater levels around the building, taking into consideration the influence of the flood wave from the Danube on groundwater filtration in the investment area. Based on modelling results the suitable technical solutions were proposed, which allow limiting the effect on the surrounding buildings and the potential changes of water levels in the investment area.

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Wang, Jiaan. "Research Progress of Underground Water and Water Environment Mathematical Model". Applied and Computational Engineering 3, n. 1 (25 maggio 2023): 216–24. http://dx.doi.org/10.54254/2755-2721/3/20230417.

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Nowadays, as global climate is getting worse, the water used in daily life or industry is not as good as previous time. therefore, it is essential to have the ability to accurately predict the environment of underground water as well as the characteristics of the water itself in order to accurately evaluate the significance of water and underground water. Models such as the generalized channel model, the visual Modflow model, and the generalized boundary and outlet model are used throughout the sections to evaluate underground water and water protection, to apply to some real-world examples, and to forecast future developments. These models are used to apply the findings of the evaluations to real-world situations. The purpose of this paper is to investigate the public's access to and knowledge of the water quality of the Yueyang Yangtze River, as well as to discuss related challenges in the environmental impact prediction of groundwater.

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Rahnama, Mohammad Bagher, e Abbas Zamzam. "Quantitative and qualitative simulation of groundwater by mathematical models in Rafsanjan aquifer using MODFLOW and MT3DMS". Arabian Journal of Geosciences 6, n. 3 (23 giugno 2011): 901–12. http://dx.doi.org/10.1007/s12517-011-0364-x.

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41

Małloszewski, P., e A. Zuber. "On the calibration and validation of mathematical models for the interpretation of tracer experiments in groundwater". Advances in Water Resources 15, n. 1 (gennaio 1992): 47–62. http://dx.doi.org/10.1016/0309-1708(92)90031-v.

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42

Al-Rekabi, Wisam Sabeeh. "A COMPARISON STUDY BETWEEN TWO MATHEMATICAL MODELS OF GROUNDWATER FLOW SIMULATION IN TEEB AREA, MISSAN PROVINCE". Kufa Journal of Engineering 7, n. 2 (5 luglio 2016): 74–89. http://dx.doi.org/10.30572/2018/kje/721213.

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Two-dimensional mathematical models are developed to simulate the flow regime of the upper part of Quaternary Deposits by two approaches finite difference and finite element. The suggested conceptual model, which is advocated to simulate the flow regime of aquifer is fixed for one layer, i.e. the activity of the deeper aquifer is negligible. The models are calibrated using trial and error procedure in two stages, steady state followed by unsteady state. Calibrated value of hydraulic conductivity and specific yield using MODFLOW (finite difference) and MICROFEM (finite element) simulations for both steady and unsteady states ranged (1-10) m/day while the specific yield ranges between (0.1- 0.4). For steady state condition, the mean absolute errors are 0.249 and 0.133 for MODFLOW and MICROFEM respectively. For unsteady state condition, the mean absolute errors are 0.025 and 0.02 for MODFLOW and MICROFEM respectively. The results of MODFLOW and MICROFEM shows that the flow in the study area from northeast to southwest.

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Daliev, Sherzod, Dilshod Karshiev, Yuldosh Islamov e Umida Sharipova. "Mathematical modeling of salt concentration change process in two-layer aqueous media". E3S Web of Conferences 401 (2023): 02009. http://dx.doi.org/10.1051/e3sconf/202340102009.

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A mathematical model was developed to monitor and predict changes in salt concentration in groundwater in a two-layer environment, representing the process of salinization and swamping. A qualitative analysis of scientific research on the problem is provided. Since the process is represented by a differential equation, effective numerical computational algorithms were developed to solve the problem of salt concentration change in groundwater based on a stable disclosure scheme with high-order accuracy relative to time and spatial variables. Mathematical models of salt transport during geo-filtration processes were improved, and computational algorithms were developed, taking into account such important parameters as the physical and mechanical properties: water loss coefficient, diffusion coefficients, and filtration rates depending on the water level. The results obtained based on these developed numerical algorithms were analyzed. Before introducing new technologies, recommendations were developed to predict changes in salt content in water using an effective numerical algorithm. Based on the laws of motion of wastewater flows, it was noted that it is possible to conduct experiments using algorithms to determine the changes in distance and velocity of wastewater propagation with water-soluble chemicals and active properties in soil layers.

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Μανάκος, A., e Γ. Δημόπουλος. "CONTRIBUTION OF SEASONAL STOCHASTIC MODELS SARIMA TO THE RATIONAL WATER RESOURCES MANAGEMENT. THE CASE OF THE KRANIA ELASSONA KARST SYSTEM, THESSALY, GREECE". Bulletin of the Geological Society of Greece 36, n. 4 (1 gennaio 2004): 2012. http://dx.doi.org/10.12681/bgsg.16700.

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Several stochastic models, known as Box and Jenkins or SARIMA (Seasonal Autoregressive Integrated Moving Average) have been used in the past for forecasting hydrological time series in general and stream flow or spring discharge time series in particular. SARIMA models became very popular because of their simple mathematical structure, convenient representation of data in terms of a relatively small number of parameters and their applicability to stationary as well as nonstationary process.Application of the seasonal stochastic model SARIMA to the spring's monthly discharge time series for the period 1974-1993 in Krania Elassona karst system yielded the following results. Logarithms of the monthly spring discharge time series can be simulated on a SARIMA (4,1,1)(1,1,1)12 type model. This type of model is suitable for the Krania Elassona karst system simulation and can be utilised as a tool to predict monthly discharge values at Kafalovriso spring for at least a 2 year period. Seasonal stochastic models SARIMA seem to be capable of simulating both runoff and groundwater flow conditions on a karst system and also easily adapt to their natural conditions.Adapting the proper stochastic model to the karst groundwater flow conditions offers the possibility to obtain accurate short term predictions, thus contributing to rational groundwater resources exploitation and management planning

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Aniszewski, Andrzej. "Description and Verification of the Contaminat Transport Models in Groundwater (Theory And Practice)". Archives of Environmental Protection 39, n. 3 (1 settembre 2013): 3–21. http://dx.doi.org/10.2478/aep-2013-0021.

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Abstract This paper presents a general overview of 2D mathematical models for both the inorganic and the organic contaminants moving in an aquifer, taking into consideration the most important processes that occur in the ground. These processes affect, to a different extent, the concentration reduction values for the contaminants moving in a groundwater. In this analysis, the following processes have been taken into consideration: reversible physical non-linear adsorption, chemical and biological reactions (as biodegradation/biological denitrification) and radioactive decay (for moving radionuclides). Based on these 2D contaminant transport models it has been possible to calculate numerically the dimensionless concentration values with and without all the chosen processes in relation to both the chosen natural site (piezometers) and the chosen contaminants.In this paper, it has also been possible to compare all the numerically calculated concentration values to the measured concentration ones (in the chosen earlier piezometers) in relation to both the new unpublished measurement series of May 1982 and the new set of parameters used in these 2D contaminant transport models (as practical verification of these models).

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Iglesias Martínez, Eva. "La gestión de las aguas subterráneas en el acuífero Mancha Occidental". Economía Agraria y Recursos Naturales 2, n. 1 (23 ottobre 2011): 69. http://dx.doi.org/10.7201/earn.2002.01.04.

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This research focuses on the particular problem that emerges in overexploited aquifers when environmental externalities are present. This is the case of Mancha Occidental where environmental externalities derive from the interrelation of groundwater reserves and the preservation of Tablas de Daimiel wetlands. Several mathematical programming models are developed to evaluate alternative groundwater management policies aimed to assure the preservation of the wetlands. The results permit to argue that the Gisser-Sánchez rule, which states that gains derived from optimal management in groundwater are not significant, may be questionable. Moreover, the results show that differences in groundwater management policies are strongly determinant. In the first place, it has to be emphasized that a fix quota system could result in significant inefficiencies, both from the agricultural sector perspective and from the environmental perspective. Secondly, a payment system implemented to compensate the application of water quotas might cause undesired long term effects, as its relative compensation value will diminish as the aquifer’s recovery level increases. Finally, the results show that a water banking system may contribute to reconcile farmers´ interest and the preservation of the wetlands.

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Xin, Yawen, Zhifang Zhou, Mingwei Li e Chao Zhuang. "Analytical Solutions for Unsteady Groundwater Flow in an Unconfined Aquifer under Complex Boundary Conditions". Water 12, n. 1 (24 dicembre 2019): 75. http://dx.doi.org/10.3390/w12010075.

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The response laws of groundwater dynamics on the riverbank to river level variations are highly dependent on the river level fluctuation process. Analytical solutions are widely used to infer the groundwater flow behavior. In analytical calculations, the river level variation is usually generalized as instantaneous uplift or stepped, and then the analytical solution of the unsteady groundwater flow in the aquifer is derived. However, the river level generally presents a complex, non-linear, continuous change, which is different from the commonly used assumptions in groundwater theoretical calculations. In this article, we propose a piecewise-linear approximation to describe the river level fluctuation. Based on the conceptual model of the riverbank aquifer system, an analytical solution of unsteady groundwater flow in an unconfined aquifer under complex boundary conditions is derived. Taking the Xiluodu Hydropower Station as an example, firstly, the monitoring data of the river level during the period of non-impoundment in the study area are used to predict the groundwater dynamics with piecewise-linear and piecewise-constant step approximations, respectively, and the long-term observation data are used to verify the calculation accuracy for the different mathematical models mentioned above. During the reservoir impoundment period, the piecewise-linear approximation is applied to represent the reservoir water level variation, and to predict the groundwater dynamics of the reservoir bank.

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Javadinejad, Safieh, Rebwar Dara e Forough Jafary. "How groundwater level can predict under the effect of climate change by using artificial neural networks of NARX". Resources Environment and Information Engineering 2, n. 1 (2020): 90–99. http://dx.doi.org/10.25082/reie.2020.01.005.

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The phenomenon of climate change in recent years has led to significant changes in climatic elements and as a result the status of surface and groundwater resources, especially in arid and semi-arid regions, this issue has sometimes caused a significant decline in groundwater resources. In this paper, the effects of climate change on the status of groundwater resources in Marvdasht plain have been investigated. Water supply of different parts of this region is highly dependent on groundwater resources and therefore the study of groundwater changes in future periods is important in the development of this plain and the management of its water resources. In order to evaluate the effects of climate change, the output of atmospheric circulation models (GCM) has been used. Then, in order to adapt the output scale of these models to the scale required by local studies of climate change, precipitation and temperature data have been downscaled by LARS-WG model. Downscaled information was used to determine the amount of feed and drainage of the aquifer in future periods. To investigate changes in groundwater levels at different stages, a neural network dynamic model has been developed in MATLAB software environment. It is also possible to study and compare other points using other scenarios and mathematical modeling. The results of the study, assuming the current state of development in the region, indicate a downward trend in the volume of the aquifer due to climate change and its effects on resources and uses of the study area. The results also introduce Scenario A2 as the most critical scenario related to climate change, which also shows the largest aquifer decline in neural network modeling.

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Villars, Monique, Mark Gerath e Don Galya. "Review of mathematical models for health risk assessment: III. Chemical concentrations in surface water, groundwater and soil". Environmental Software 8, n. 3 (gennaio 1993): 135–55. http://dx.doi.org/10.1016/0266-9838(93)90011-6.

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Mohammed, G. A., W. Zijl, O. Batelaan e F. De Smedt. "Comparison of Two Mathematical Models for 3D Groundwater Flow: Block-Centered Heads and Edge-Based Stream Functions". Transport in Porous Media 79, n. 3 (4 febbraio 2009): 469–85. http://dx.doi.org/10.1007/s11242-009-9336-y.

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