Journal articles on the topic 'Groundwater flow – Mathematical models'
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1
Fowler, A. C., and C. G. Noon. "Mathematical models of compaction, consolidation and regional groundwater flow." Geophysical Journal International 136, no. 1 (January 1, 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, no. 2 (March 2008): 205–11. http://dx.doi.org/10.1134/s0097807808020097.
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Boyraz, Uğur, and Cevza Melek Kazezyılmaz-Alhan. "Solutions for groundwater flow with sloping stream boundary: analytical, numerical and experimental models." Hydrology Research 49, no. 4 (June 9, 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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Yakirevich, Alexander. "Water Flow, Solute and Heat Transfer in Groundwater." Water 12, no. 7 (June 28, 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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Vinda, Ram Raj, Raja Ram Yadava, and Naveen Kumar. "Uniform Horizontal Groundwater Flow against Dispersion in a Shallow Aquifer: Two Analytical Models." Hydrology Research 23, no. 1 (February 1, 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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Smith, W. R., G. C. Wake, J. E. McIntosh, R. P. McIntosh, M. Pettigrew, and R. Kao. "Mathematical analysis of perifusion data: models predicting elution concentration." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 261, no. 1 (July 1, 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, and Yun Zhang Zhao. "Groundwater Flow Simulation and Resource Evaluation of the Affected Zone along the Yellow River (Henan Section)." Advanced Materials Research 610-613 (December 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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Aniszewski, A. "Incorporation of advection and adsorption in modeling ground water quality." Water Supply 1, no. 2 (March 1, 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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Παναγόπουλος, A., E. Δρακοπούλου, and 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, no. 4 (January 1, 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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de Rooij, G. H. "Is the groundwater reservoir linear? A mathematical analysis of two limiting cases." Hydrology and Earth System Sciences Discussions 11, no. 1 (January 6, 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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Kolditz, Olaf, Jens-Olaf Delfs, Claudius Bürger, Martin Beinhorn, and Chan-Hee Park. "Numerical analysis of coupled hydrosystems based on an object-oriented compartment approach." Journal of Hydroinformatics 10, no. 3 (May 1, 2008): 227–44. http://dx.doi.org/10.2166/hydro.2008.003.
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In this paper we present an object-oriented concept for numerical simulation of multi-field problems for coupled hydrosystem analysis. Individual (flow) processes modelled by a particular partial differential equation, i.e. overland flow by the shallow water equation, variably saturated flow by the Richards equation and saturated flow by the groundwater flow equation, are identified with their corresponding hydrologic compartments such as land surface, vadose zone and aquifers, respectively. The object-oriented framework of the compartment approach allows an uncomplicated coupling of these existing flow models. After a brief outline of the underlying mathematical models we focus on the numerical modelling and coupling of overland flow, variably saturated and groundwater flows via exchange flux terms. As each process object is associated with its own spatial discretisation mesh, temporal time-stepping scheme and appropriate numerical solution procedure. Flow processes in hydrosystems are coupled via their compartment (or process domain) boundaries without giving up the computational necessities and optimisations for the numerical solution of each individual process. However, the coupling requires a bridging of different temporal and spatial scales, which is solved here by the integration of fluxes (spatially and temporally). In closing we present three application examples: a benchmark test for overland flow on an infiltrating surface and two case studies – at the Borden site in Canada and the Beerze–Reusel drainage basin in the Netherlands.
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Μανάκος, A., and 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, no. 4 (January 1, 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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Xin, Yawen, Zhifang Zhou, Mingwei Li, and Chao Zhuang. "Analytical Solutions for Unsteady Groundwater Flow in an Unconfined Aquifer under Complex Boundary Conditions." Water 12, no. 1 (December 24, 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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Tahershamsi, Ahmad, Atabak Feizi, and Siavash Molaei. "Modeling Groundwater Surface by MODFLOW Math Code and Geostatistical Method." Civil Engineering Journal 4, no. 4 (May 3, 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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Krusteva, Ekaterina D., Stefan Y. Radoslavov, and Zdravko I. Diankov. "Modelling the Seepage of Groundwater: Application of the Viscous Analogy and Numerical Methods." Applied Rheology 9, no. 4 (August 1, 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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Mohammed, G. A., W. Zijl, O. Batelaan, and 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, no. 3 (February 4, 2009): 469–85. http://dx.doi.org/10.1007/s11242-009-9336-y.
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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 (March 1, 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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Jha, Madan K., Richard C. Peralta, and 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, no. 10 (May 18, 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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Regnier, P., P. Jourabchi, and C. P. Slomp. "Reactive-Transport modeling as a technique for understanding coupled biogeochemical processes in surface and subsurface environments." Netherlands Journal of Geosciences - Geologie en Mijnbouw 82, no. 1 (April 2003): 5–18. http://dx.doi.org/10.1017/s0016774600022757.
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AbstractReactive-transport models contribute significantly to the field of modern geosciences. A general mathematical approach to solving models of complex biogeochemical systems is introduced. It is argued that even though mathematical models for reactive-transport simulations can be developed at various levels of approximation, the approach for their construction and application to the various compartments of the hydrosphere is fundamentally the same. The workings of coupled transport-reaction systems are described in more detail by means of examples, which demonstrate the similarities in the approach. Three models of the carbon dynamics in redox-stratified environments are compared: porous media flow problems in a coastal sediment and in a contaminated groundwater system; and a surface flow problem in a eutrophic estuary. Considering the interdisciplinary nature of such models, a Knowledge Base System for biogeochemical processes is proposed. Incorporation of the proposed knowledge base in an appropriate modeling framework, such as the Biogeochemical Reaction Network Simulator, proves an effective approach to the modeling of complex natural systems. This methodology allows for construction of multi-component reactive-transport models applicable to a wide range of problems of interest to the geoscientist.
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Hoc, Ryszard, Andrzej Sadurski, and Zenon Wiśniowski. "A groundwater flow model for the Wolin Island area, including glaciotectonic deformation." Geologos 24, no. 3 (December 1, 2018): 207–16. http://dx.doi.org/10.2478/logos-2018-0021.
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Abstract During the construction of mathematical models for mapping hydrogeological conditions it is necessary to apply simplifications, both in the geological structure and in hydrogeological parameters used. The present note discusses problems surrounding the mapping of glaciotectonic disturbances that occur in the northern part of Wolin Island (northwest Poland). For this part of the island, a direct outflow of groundwater towards the Baltic Sea basin has been determined on the basis of geophysical survey results. An important feature in the hydrogeological conditions here is the isolation of groundwater from both the Baltic Sea and Szczecin Lagoon by clay with a Cretaceous xenolith. Such a geological structure explains the presence of perched water at considerable heights in zones close to the cliffs, without any significant hydraulic connection with surrounding reservoirs. Hydrogeological conditions of Wolin Island have been modelled using the Visual MODFLOW package v.4.2. In the vertical section, these conditions can be simplified to one aquifer (Pleistocene-Holocene), in which two aquifers can be distinguished. In a large part of the island, these remain in mutual hydraulic contact: layer I – upper, with an unconfined aquifer, and layer II – lower, with a confined aquifer, locally an unconfined one. The schematisation of hydrogeological conditions adopted here has allowed to reproduce present groundwater dynamics in the study area.
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KOWALÓW, Mariusz, Marta CHRYŚCINA, and 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 (October 1, 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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El-Rawy, Mustafa, Okke Batelaan, Kerst Buis, Christian Anibas, Getachew Mohammed, Wouter Zijl, and Ali Salem. "Analytical and Numerical Groundwater Flow Solutions for the FEMME-Modeling Environment." Hydrology 7, no. 2 (May 12, 2020): 27. http://dx.doi.org/10.3390/hydrology7020027.
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Simple analytical and numerical solutions for confined and unconfined groundwater-surface water interaction in one and two dimensions were developed in the STRIVE package (stream river ecosystem) as part of FEMME (flexible environment for mathematically modelling the environment). Analytical and numerical solutions for interaction between one-dimensional confined and unconfined aquifers and rivers were used to study the effects of a 0.5 m sudden rise in the river water level for 24 h. Furthermore, a two-dimensional groundwater model for an unconfined aquifer was developed and coupled with a one-dimensional hydrodynamic model. This model was applied on a 1 km long reach of the Aa River, Belgium. Two different types of river water level conditions were tested. A MODFLOW model was set up for these different types of water level condition in order to compare the results with the models implemented in STRIVE. The results of the analytical solutions for confined and unconfined aquifers were in good agreement with the numerical results. The results of the two-dimensional groundwater model developed in STRIVE also showed that there is a good agreement with the MODFLOW solutions. It is concluded that the facilities of STRIVE can be used to improve the understanding of groundwater-surface water interaction and to couple the groundwater module with other modules developed for STRIVE. With these new models STRIVE proves to be a powerful example as a development and testing environment for integrated water modeling.
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Lo, Weicheng, Sanidhya Nika Purnomo, Bondan Galih Dewanto, Dwi Sarah, and Sumiyanto. "Integration of Numerical Models and InSAR Techniques to Assess Land Subsidence Due to Excessive Groundwater Abstraction in the Coastal and Lowland Regions of Semarang City." Water 14, no. 2 (January 11, 2022): 201. http://dx.doi.org/10.3390/w14020201.
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This study was carried out to assess land subsidence due to excessive groundwater abstraction in the northern region of Semarang City by integrating the application of both numerical models and geodetic measurements, particularly those based on the synthetic aperture radar interferometry (InSAR) technique. Since 1695, alluvial deposits caused by sedimentations have accumulated in the northern part of Semarang City, in turn resulting in changes in the coastline and land use up to the present. Commencing in 1900, excessive groundwater withdrawal from deep wells in the northern section of Semarang City has exacerbated natural compaction and aggravated the problem of land subsidence. In the current study, a groundwater model equivalent to the hydrogeological system in this area was developed using MODFLOW to simulate the hydromechanical coupling of groundwater flow and land subsidence. The numerical computation was performed starting with the steady-state flow model from the period of 1970 to 1990, followed by the model of transient flow and land subsidence from the period of 1990 to 2010. Our models were calibrated with deformation data from field measurements collected from various sources (e.g., leveling, GPS, and InSAR) for simulation of land subsidence, as well as with the hydraulic heads from observation wells for simulation of groundwater flow. Comparison of the results of our numerical calculations with recorded observations led to low RMSEs, yet high R2 values, mathematically indicating that the simulation outcomes are in good agreement with monitoring data. The findings in the present study also revealed that land subsidence arising from groundwater pumping poses a serious threat to the northern part of Semarang City. Two groundwater management measures are proposed and the future development of land subsidence is accordingly projected until 2050. Our study shows quantitatively that the greatest land subsidence occurs in Genuk District, with a magnitude of 36.8 mm/year. However, if the suggested groundwater management can be implemented, the rate and affected area of land subsidence can be reduced by up to 59% and 76%, respectively.
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Shu, Lele, Paul A. Ullrich, and Christopher J. Duffy. "Simulator for Hydrologic Unstructured Domains (SHUD v1.0): numerical modeling of watershed hydrology with the finite volume method." Geoscientific Model Development 13, no. 6 (June 18, 2020): 2743–62. http://dx.doi.org/10.5194/gmd-13-2743-2020.
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Abstract. Hydrologic modeling is an essential strategy for understanding and predicting natural flows, particularly where observations are lacking in either space or time or where complex terrain leads to a disconnect in the characteristic time and space scales of overland and groundwater flow. However, significant difficulties remain for the development of efficient and extensible modeling systems that operate robustly across complex regions. This paper introduces the Simulator for Hydrologic Unstructured Domains (SHUD), an integrated, multiprocess, multiscale, flexible-time-step model, in which hydrologic processes are fully coupled using the finite volume method. SHUD integrates overland flow, snow accumulation/melt, evapotranspiration, subsurface flow, groundwater flow, and river routing, thus allowing physical processes in general watersheds to be realistically captured. SHUD incorporates one-dimensional unsaturated flow, two-dimensional groundwater flow, and a fully connected river channel network with hillslopes supporting overland flow and baseflow. The paper introduces the design of SHUD, from the conceptual and mathematical description of hydrologic processes in a watershed to the model's computational structures. To demonstrate and validate the model performance, we employ three hydrologic experiments: the V-catchment experiment, Vauclin's experiment, and a model study of the Cache Creek Watershed in northern California. Ongoing applications of the SHUD model include hydrologic analyses of hillslope to regional scales (1 m2 to 106 km2), water resource and stormwater management, and interdisciplinary research for questions in limnology, agriculture, geochemistry, geomorphology, water quality, ecology, climate and land-use change. The strength of SHUD is its flexibility as a scientific and resource evaluation tool where modeling and simulation are required.
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Tanachaichoksirikun, Pinit, and Uma Seeboonruang. "Distributions of Groundwater Age under Climate Change of Thailand’s Lower Chao Phraya Basin." Water 12, no. 12 (December 10, 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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Reimann, T., M. Giese, T. Geyer, R. Liedl, J. C. Maréchal, and W. B. Shoemaker. "Representation of water abstraction from a karst conduit with numerical discrete-continuum models." Hydrology and Earth System Sciences 18, no. 1 (January 17, 2014): 227–41. http://dx.doi.org/10.5194/hess-18-227-2014.
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Abstract. Karst aquifers are characterized by highly conductive conduit flow paths embedded in a less conductive fissured and fractured matrix, resulting in strong permeability contrasts with structured heterogeneity and anisotropy. Groundwater storage occurs predominantly in the fissured matrix. Hence, most mathematical karst models assume quasi-steady-state flow in conduits neglecting conduit-associated drainable storage (CADS). The concept of CADS considers storage volumes, where karst water is not part of the active flow system but hydraulically connected to conduits (for example karstic voids and large fractures). The disregard of conduit storage can be inappropriate when direct water abstraction from karst conduits occurs, e.g., large-scale pumping. In such cases, CADS may be relevant. Furthermore, the typical fixed-head boundary condition at the karst outlet can be inadequate for water abstraction scenarios because unhampered water inflow is possible. The objective of this work is to analyze the significance of CADS and flow-limited boundary conditions on the hydraulic behavior of karst aquifers in water abstraction scenarios. To this end, the numerical discrete-continuum model MODFLOW-2005 Conduit Flow Process Mode 1 (CFPM1) is enhanced to account for CADS. Additionally, a fixed-head limited-flow (FHLQ) boundary condition is added that limits inflow from constant head boundaries to a user-defined threshold. The effects and the proper functioning of these modifications are demonstrated by simplified model studies. Both enhancements, CADS and FHLQ boundary, are shown to be useful for water abstraction scenarios within karst aquifers. An idealized representation of a large-scale pumping test in a karst conduit is used to demonstrate that the enhanced CFPM1 is able to adequately represent water abstraction processes in both the conduits and the matrix of real karst systems, as illustrated by its application to the Cent Fonts karst system.
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Chalfen, Mieczysław, Wojciech Łyczko, and Leszek Pływaczyk. "The Prognosis of Influence of The Oder River Waters Dammed by Malczyce Barrage on Left Bank Areas." Journal of Water and Land Development 21, no. 1 (July 29, 2014): 19–27. http://dx.doi.org/10.2478/jwld-2014-0010.
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Abstract The finalisation of the construction of the Malczyce barrage is planned for 2015. Damming of the river will cause a change in the water and ground conditions in the adjoining areas. The paper analyses the influence of the water level in the Oder River dammed by the barrage on groundwater table level in the left bank valley. A model which allows the prediction of groundwater levels depending on the assumed water level in the Oder was constructed. The analysis was conducted for three different variants: for the initial stage before damming the Oder River and for the conditions after damming the water up with and without the drainage devices included in the project. The calculations were done in several chosen transects across the river valley. The mathematical model of flow in the aquifer based on the Richards equation was applied. The results of calculations were presented as the spatial distribution of piezometric pressures which were used to determine the groundwater table for each of the transects. The calculation results from the vertical models were transposed into a horizontal model. The comparison of appropriate results allowed to positively verify the designed model and to analyse the effectiveness of the realised project solutions.
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Flowers, Gwenn E. "Modelling water flow under glaciers and ice sheets." Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 471, no. 2176 (April 2015): 20140907. http://dx.doi.org/10.1098/rspa.2014.0907.
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Recent observations of dynamic water systems beneath the Greenland and Antarctic ice sheets have sparked renewed interest in modelling subglacial drainage. The foundations of today's models were laid decades ago, inspired by measurements from mountain glaciers, discovery of the modern ice streams and the study of landscapes evacuated by former ice sheets. Models have progressed from strict adherence to the principles of groundwater flow, to the incorporation of flow ‘elements’ specific to the subglacial environment, to sophisticated two-dimensional representations of interacting distributed and channelized drainage. Although presently in a state of rapid development, subglacial drainage models, when coupled to models of ice flow, are now able to reproduce many of the canonical phenomena that characterize this coupled system. Model calibration remains generally out of reach, whereas widespread application of these models to large problems and real geometries awaits the next level of development.
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Tran, Hoang, Elena Leonarduzzi, Luis De la Fuente, Robert Bruce Hull, Vineet Bansal, Calla Chennault, Pierre Gentine, Peter Melchior, Laura E. Condon, and Reed M. Maxwell. "Development of a Deep Learning Emulator for a Distributed Groundwater–Surface Water Model: ParFlow-ML." Water 13, no. 23 (December 1, 2021): 3393. http://dx.doi.org/10.3390/w13233393.
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Integrated hydrologic models solve coupled mathematical equations that represent natural processes, including groundwater, unsaturated, and overland flow. However, these models are computationally expensive. It has been recently shown that machine leaning (ML) and deep learning (DL) in particular could be used to emulate complex physical processes in the earth system. In this study, we demonstrate how a DL model can emulate transient, three-dimensional integrated hydrologic model simulations at a fraction of the computational expense. This emulator is based on a DL model previously used for modeling video dynamics, PredRNN. The emulator is trained based on physical parameters used in the original model, inputs such as hydraulic conductivity and topography, and produces spatially distributed outputs (e.g., pressure head) from which quantities such as streamflow and water table depth can be calculated. Simulation results from the emulator and ParFlow agree well with average relative biases of 0.070, 0.092, and 0.032 for streamflow, water table depth, and total water storage, respectively. Moreover, the emulator is up to 42 times faster than ParFlow. Given this promising proof of concept, our results open the door to future applications of full hydrologic model emulation, particularly at larger scales.
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Ferronato, M., C. Janna, and G. Pini. "Shifted FSAI preconditioners for the efficient parallel solution of non-linear groundwater flow models." International Journal for Numerical Methods in Engineering 89, no. 13 (November 5, 2011): 1707–19. http://dx.doi.org/10.1002/nme.3309.
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Rábade, H. G., P. Vellando, F. Padilla, and R. Juncosa. "A coupled FE model for the joint resolution of the shallow water and the groundwater flow equations." International Journal of Numerical Methods for Heat & Fluid Flow 24, no. 7 (August 26, 2014): 1553–69. http://dx.doi.org/10.1108/hff-05-2012-0123.
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Purpose – A new coupled finite element model has been developed for the joint resolution of both the shallow water equations, that governs the free surface flow, and the groundwater flow equation that governs the motion of water through a porous media. The paper aims to discuss these issues. Design/methodology/approach – The model is based upon two different modules (surface and ground water) previously developed by the authors, that have been validated separately. Findings – The newly developed software allows for the assessment of the fluid flow in natural watersheds taking into account both the surface and the underground flow in the way it really takes place in nature. Originality/value – The main achievement of this work has dealt with the coupling of both models, allowing for a proper moving interface treatment that simulates the actual interaction that takes place between surface and groundwater in natural watersheds.
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Yang, Bin, Tianhong Yang, Zenghe Xu, Honglei Liu, Wenhao Shi, and Xin Yang. "Numerical simulation of the free surface and water inflow of a slope, considering the nonlinear flow properties of gravel layers: a case study." Royal Society Open Science 5, no. 2 (February 2018): 172109. http://dx.doi.org/10.1098/rsos.172109.
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Groundwater is an important factor of slope stability, and 90% of slope failures are related to the influence of groundwater. In the past, free surface calculations and the prediction of water inflow were based on Darcy's law. However, Darcy's law for steady fluid flow is a special case of non-Darcy flow, and many types of non-Darcy flows occur in practical engineering applications. In this paper, based on the experimental results of laboratory water seepage tests, the seepage state of each soil layer in the open-pit slope of the Yanshan Iron Mine, China, were determined, and the seepage parameters were obtained. The seepage behaviour in the silt layer, fine sand layer, silty clay layer and gravelly clay layer followed the traditional Darcy law, while the gravel layers showed clear nonlinear characteristics. The permeability increases exponentially and the non-Darcy coefficient decreases exponentially with an increase in porosity, and the relation among the permeability, the porosity and the non-Darcy coefficient is investigated. A coupled mathematical model is established for two flow fields, on the basis of Darcy flow in the low-permeability layers and Forchheimer flow in the high-permeability layers. In addition, the effect of the seepage in the slope on the transition from Darcy flow to Forchheimer flow was considered. Then, a numerical simulation was conducted by using finite-element software (FELAC 2.2). The results indicate that the free surface calculated by the Darcy–Forchheimer model is in good agreement with the in situ measurements; however, there is an evident deviation of the simulation results from the measured data when the Darcy model is used. Through a parameter sensitivity analysis of the gravel layers, it can be found that the height of the overflow point and the water inflow calculated by the Darcy–Forchheimer model are consistently less than those of the Darcy model, and the discrepancy between these two models increases as the permeability increases. The necessity of adopting the Darcy–Forchheimer model was explained. The Darcy–Forchheimer model would be applicable in slope engineering applications with highly permeable rock.
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Bian, Kai, Shi Lei Chen, Xue Yuan Li, and Ying Wang Zhao. "Numerical Simulation of Seepage Field in Aquifer under the Coal Seam." Advanced Materials Research 955-959 (June 2014): 3120–24. http://dx.doi.org/10.4028/www.scientific.net/amr.955-959.3120.
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In order to figure out seepage field in aquifer under the coal seam, the geology and hydrogeology conditions systematically of study area were analyzed, hydrogeological conceptual model was generalized, mathematical model was built, seepage field of the Taiyuan limestone aquifer was simulated with software Feflow. Simulation results show that hydrogeological parameters of Taiyuan limestone aquifer change greatly in different partitions. The model also indicates the heterogeneity of karst fissure of Taiyuan limestone aquifer. The drainage quantity is from the Ordovician limestone aquifer besides supplying from runoff of upstream and capture excretion of downstream. The research is an attempt to simulate the seepage field in aquifer under coal seam, to some extent, it also provides a technical basis for safe coal mining and as a reference for simulation constructions of three-dimensional groundwater flow models in similar coal mines.
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Huang, C. S., J. J. Chen, and H. D. Yeh. "Analysis of three-dimensional groundwater flow toward a radial collector well in a finite-extent unconfined aquifer." Hydrology and Earth System Sciences Discussions 12, no. 8 (August 6, 2015): 7503–40. http://dx.doi.org/10.5194/hessd-12-7503-2015.
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Abstract. This study develops a three-dimensional mathematical model for describing transient hydraulic head distributions due to pumping at a radial collector well (RCW) in a rectangular confined or unconfined aquifer bounded by two parallel streams and no-flow boundaries. The governing equation with a point-sink term is employed. A first-order free surface equation delineating the water table decline induced by the well is considered. The head solution for the point sink is derived by applying the methods of double-integral transform and Laplace transform. The head solution for a RCW is obtained by integrating the point-sink solution along the laterals of the RCW and then dividing the integration result by the sum of lateral lengths. On the basis of Darcy's law and head distributions along the streams, the solution for the stream depletion rate (SDR) can also be developed. With the aid of the head and SDR solutions, the sensitivity analysis can then be performed to explore the response of the hydraulic head to the change in a specific parameter such as the horizontal and vertical hydraulic conductivities, streambed permeability, specific storage, specific yield, lateral length and well depth. Spatial head distributions subject to the anisotropy of aquifer hydraulic conductivities are analyzed. A quantitative criterion is provided to identify whether groundwater flow at a specific region is 3-D or 2-D without the vertical component. In addition, another criterion is also given to allow the neglect of vertical flow effect on SDR. Conventional 2-D flow models can be used to provide accurate head and SDR predictions if satisfying these two criteria.
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Mousty, Paul, Jean-Paul Morvan, and André Grimaud. "Automatic Warning Stations, Recent Serious Industrial River Pollution Incidents, and Prediction Models of Pollutants Propagation–Some European Examples." Water Science and Technology 22, no. 5 (May 1, 1990): 259–64. http://dx.doi.org/10.2166/wst.1990.0038.
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The automatic analysing station located just downstream of the Basel urban area at Huningue, consists of an alarm station linking the automatic detection of certain important pollution parameters (T.O.C., hydrocarbons, heavy metals, pesticides, etc.). and the resulting alarms, to a working mathematical model of pollutant plume propagation, operating on the river between Basel and Strasbourg. This model is keyed to the real flow conditions of the Rhine, determined by life-size tracing operations (using coloured Rhodamine marker). A decisive factor in speeding up the transmission of alarm signals, this system allows, among other things, optimum management of the valves and locks communicating with the Rhine, in order to avoid the penetration of the pollutants into the ramifications of the hydrographic network feeding the groundwater table in Alsace. The alarm station put into service on the Rhine can look back on 10 years experience in the struggle against accidental pollutions which primarily occurred in the Paris area. There, an important alarm network consisting of eight automatic analysing stations was set up on the rivers Seine, Marne and Oise to protect the most important drinking water supply of France which provides water to more than 4 million inhabitants.
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Huang, C. S., J. J. Chen, and H. D. Yeh. "Approximate analysis of three-dimensional groundwater flow toward a radial collector well in a finite-extent unconfined aquifer." Hydrology and Earth System Sciences 20, no. 1 (January 15, 2016): 55–71. http://dx.doi.org/10.5194/hess-20-55-2016.
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Abstract. This study develops a three-dimensional (3-D) mathematical model for describing transient hydraulic head distributions due to pumping at a radial collector well (RCW) in a rectangular confined or unconfined aquifer bounded by two parallel streams and no-flow boundaries. The streams with low-permeability streambeds fully penetrate the aquifer. The governing equation with a point-sink term is employed. A first-order free surface equation delineating the water table decline induced by the well is considered. Robin boundary conditions are adopted to describe fluxes across the streambeds. The head solution for the point sink is derived by applying the methods of finite integral transform and Laplace transform. The head solution for a RCW is obtained by integrating the point-sink solution along the laterals of the RCW and then dividing the integration result by the sum of lateral lengths. On the basis of Darcy's law and head distributions along the streams, the solution for the stream depletion rate (SDR) can also be developed. With the aid of the head and SDR solutions, the sensitivity analysis can then be performed to explore the response of the hydraulic head to the change in a specific parameter such as the horizontal and vertical hydraulic conductivities, streambed permeability, specific storage, specific yield, lateral length, and well depth. Spatial head distributions subject to the anisotropy of aquifer hydraulic conductivities are analyzed. A quantitative criterion is provided to identify whether groundwater flow at a specific region is 3-D or 2-D without the vertical component. In addition, another criterion is also given to allow for the neglect of vertical flow effect on SDR. Conventional 2-D flow models can be used to provide accurate head and SDR predictions if satisfying these two criteria.
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Gromyko, G., M. Chuiko, A. Smychnik, A. Hrechka, and A. Zlebava. "Mathematical Modeling of Geofiltration and Geomigration Processes in Multilayer Systems." Computational Methods in Applied Mathematics 7, no. 2 (2007): 163–77. http://dx.doi.org/10.2478/cmam-2007-0009.
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AbstractNumerical methods for simultaneous solution of geofiltration and ge- omigration problems in multilayer systems in contaminant transport investigation have been developed. A multilayer system consists of several aquifers separated by weakly permeable layers. Mathematical models are constructed under the following assump- tion: longitudinal flows predominate in the aquifer and crossflows — in the separation layers. The mass transfer is described by the convection and diffusion equations. The implicit finite volume difference schemes were used. The computational al- gorithm is based on the concept of splitting the schemes on physical processes of two- dimensional filtration and contaminant transport along aquifers and vertical transport through the separation levels. An iterative method of the block Gauss — Seidel type for the realization of implicit finite difference schemes for geofiltration and geomigration problems in the presence of wells and contaminant sources has been constructed. The method is based on the perturbation transfer from cells with sources (wells and sources of contaminant). The iterative process for update of unknowns has been constructed taking into account the position of a cell relative to the calculated cells. The results of the numerical experiment on modeling groundwater flows redistri- bution and contaminant migration in system of two aquifers with operating wells are presented.
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Silva Júnior, Gerson Cardoso da, Carlos Eduardo Braga, and Ingrid De Carvalho Lage. "Hydrogeological study of mangrove areas around Guanabara Bay, Rio de Janeiro, Brazil." Anuário do Instituto de Geociências 26 (January 1, 2003): 92–100. http://dx.doi.org/10.11137/2003_0_92-100.
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The study area covers part of the mangrove belt located around Guanabara Bay, Rio de Janeiro, Brazil. Representing a continental-marine transition, the mangrove ecosystem is very susceptible to environmental variations and impacts. The vegetation cover plays an important role in prevention of erosion and contamination processes in those areas. An ongoing extensive research effort in the Petrochemical Complex of Duque de Caxias, Rio de Janeiro State, Brazil, focuses on the man-induced changes in the physical environment (soils, groundwater flow system, type and volumes of contaminants, geochemical aspects) and the consequences on the neighboring mangrove ecosystem. This article describes the importance of hydrogeological studies in mangrove areas as part of an appropriate environmental assessment, taking as an example an industrial dumping area located in that Petrochemical Complex. Field work included extensive drilling and sampling to obtain basic geological and hydrogeological parameters and data in the pilot area, such as hydraulic conductivity and piezometric heads; emphasizing the tracking of possible contamination by industrial effluents and the marine influence; validation of the conceptual model with mathematical models (numerical and analytical models) was carried out. Results show the great importance of well conducted and detailed hydrogeological studies to properly address environmental problems caused by industrial plants in mangrove areas.
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Zhai, Yuanzheng, Xinyi Cao, Ya Jiang, Kangning Sun, Litang Hu, Yanguo Teng, Jinsheng Wang, and Jie Li. "Further Discussion on the Influence Radius of a Pumping Well: A Parameter with Little Scientific and Practical Significance That Can Easily Be Misleading." Water 13, no. 15 (July 28, 2021): 2050. http://dx.doi.org/10.3390/w13152050.
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To facilitate understanding and calculation, hydrogeologists have introduced the influence radius. This parameter is now widely used, not only in the theoretical calculation and reasoning of well flow mechanics, but also in guiding production practice, and it has become an essential parameter in hydrogeology. However, the reasonableness of this parameter has always been disputed. This paper discusses the nature of the influence radius and the problems of its practical application based on mathematical reasoning and analogy starting from the Dupuit formula and Thiem formula. It is found that the influence radius is essentially the distance in the time–distance problem in physics; therefore, it is a function of time and velocity and is influenced by hydrogeological conditions and pumping conditions. Additionally, the influence radius is a variable and is essentially different from the hydrogeological parameters reflecting the natural properties of aquifers such as the porosity, specific yield, and hydraulic conductivity. Furthermore, the parameterized influence radius violates the continuity principle of fluids. In reality, there are no infinite horizontal aquifers, and most aquifers are replenished from external sources, which is very different from theory. The stable or seemingly stable groundwater level observed in practice is simply a coincidence that occurs under the influence of various practical factors, which cannot be considered to explain the rationality of applying this parameter in production calculations. Therefore, the influence radius cannot be used to evaluate the sustainable water supply capacity of aquifers, nor can it be used to guide the design of groundwater pollution remediation projects, the division of water source protection areas, and the scheme of riverbank filtration wells. Various ecological and environmental problems caused by groundwater exploitation are related to misleading information from the influence radius theory. Generally, the influence radius does not have scientific or practical significance, but it can easily be misleading, particularly for non-professionals. The influence radius should not be used in the sustainable development and protection of groundwater resources, let alone in theoretical models. From the perspective of regional overall planning, the calculation and evaluation of sustainable development and the utilization of groundwater resources should be investigated in a systematic manner.
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Rathi, Vinay Kumar, Shobha Ram, Rohitashw Kumar, Avinash Agarwal, and R. K. Nema. "Hydrological classification and performance of Himalayan springs in climate change scenario – a case study." Water Supply 20, no. 2 (December 27, 2019): 594–608. http://dx.doi.org/10.2166/ws.2019.191.
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Abstract The present study was conducted to evaluate 33 springs' hydrology (discharge and yield estimation) of Chandrabhaga and Danda watersheds of Uttarakhand, India. The springs were classified using Meinzer method and evaluated the relative performance for rejuvenation strategy. It was found that most of springs fall in sixth and seventh class order with flow rate 6.5 to 65.5 and 0.8 to 6.5 m3·day−1, respectively. The relative performance of springs were analyzed based on four methods: (i) spring flow variability, (ii) normalized spring flow (short and long duration), (iii) rainfall spring flow lag and (iv) spring flow gradient. The relative results of springs were analyzed on a scale of 0–5. The Chandrabhaga springs 01, 03, 4B, 05, 06 and 13 were found to be relatively good on a scale value of 4 out of 5 as compared to springs 4A, 07, and 10A with a scale value of 1. For the Danda watershed, the relative performance of springs 4A and 28 found on scale value of 5 and springs 4B, 11 and 20 with a scale value of 4 are relatively good compared to springs 02, 06, 07, 15 and 17. The cumulative flow of spring showed a linear response with cumulative rainfall for the period of June to September (monsoon period). The spring-shed was delineated and evaluated for optimization for the maximum efficiency, spring flow, ratio of area and relief versus maximum spring flow yield. The results revealed that the quantification of water fluxes for water balances, storage of groundwater and development of mathematical models can be used for sustainable water resources development and to revive the mountain springs which helped the adverse impacts of climate change.
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Liang, Xiuyu, Hongbin Zhan, You-Kuan Zhang, and Jin Liu. "On the coupled unsaturated–saturated flow process induced by vertical, horizontal, and slant wells in unconfined aquifers." Hydrology and Earth System Sciences 21, no. 2 (March 2, 2017): 1251–62. http://dx.doi.org/10.5194/hess-21-1251-2017.
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Abstract. Conventional models of pumping tests in unconfined aquifers often neglect the unsaturated flow process. This study concerns the coupled unsaturated–saturated flow process induced by vertical, horizontal, and slant wells positioned in an unconfined aquifer. A mathematical model is established with special consideration of the coupled unsaturated–saturated flow process and the well orientation. Groundwater flow in the saturated zone is described by a three-dimensional governing equation and a linearized three-dimensional Richards' equation in the unsaturated zone. A solution in the Laplace domain is derived by the Laplace–finite-Fourier-transform and the method of separation of variables, and the semi-analytical solutions are obtained using a numerical inverse Laplace method. The solution is verified by a finite-element numerical model. It is found that the effects of the unsaturated zone on the drawdown of a pumping test exist at any angle of inclination of the pumping well, and this impact is more significant in the case of a horizontal well. The effects of the unsaturated zone on the drawdown are independent of the length of the horizontal well screen. The vertical well leads to the largest water volume drained from the unsaturated zone (W) during the early pumping time, and the effects of the well orientation on W values become insignificant at the later time. The screen length of the horizontal well does not affect W for the whole pumping period. The proposed solutions are useful for the parameter identification of pumping tests with a general well orientation (vertical, horizontal, and slant) in unconfined aquifers affected from above by the unsaturated flow process.
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Bokhove, Onno, Tiffany Hicks, Wout Zweers, and Thomas Kent. "Wetropolis extreme rainfall and flood demonstrator: from mathematical design to outreach." Hydrology and Earth System Sciences 24, no. 5 (May 14, 2020): 2483–503. http://dx.doi.org/10.5194/hess-24-2483-2020.
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Abstract. Government and consulting experts on flood mitigation generally face difficulties when trying to explain the science of extreme flooding to the general public, in particular the concept of a return period. Too often, for example, people perceive they are safe for the next 100 years after a 1:100-year return-period flood has hit their town. UK flood practitioners therefore gave us the challenge to design an outreach tool that conceptualises the science of flooding in a way that is accessible to and directly engages the public, and in particular demonstrates what a return period is. Furthermore, we were tasked with designing a live 3-D physical model rather than a graphical or animated 2-D game on a screen. We show here how we tackled that challenge by designing, constructing, and showcasing the Wetropolis Flood Demonstrator. Wetropolis is a transportable and conceptual physical model with random rainfall, river flow, a flood plain, an upland reservoir, a porous moor, representing the upper catchment and visualising groundwater flow, and a city which can flood following extreme and random rainfall. A key novelty is the supply of rainfall every Wetropolis day. Several aspects of Wetropolis are considered. i. We present the modular mathematical and numerical design on which Wetropolis is based. It guided the choice of parameter values of Wetropolis, which was loosely inspired by the Leeds Boxing Day floods of the River Aire in 2015. The design model further serves as the building block and inspiration for adaptations suited to particular local demands. Moreover, the model is purposely lean and therefore quick to compute, serving flexibility in the outreach-tool design, but is less suitable for any detailed scientific validation.ii. The constructed Wetropolis is described here in broad terms, but we include a link to a GitHub site with details to inspire other bespoke designs. The goal, again, is to facilitate new adaptations of Wetropolis for particular catchments different to the Leeds River Aire case.iii. Our experience in showcasing Wetropolis is summarised and discussed, with the purpose of giving an overview as well as inspiring improved and bespoke adaptations. While Wetropolis should be experienced live, with videos found on the GitHub site, here we provide a photographic overview. To date, Wetropolis has been showcased to 500 to 1000 people at public workshops and exhibitions on recent UK floods, as well as to flood practitioners and scientists at various research and stakeholder workshops.iv. We conclude with some ongoing design changes, including how people can experience natural flood management in a revised Wetropolis design. Finally, we also discuss how Wetropolis, although originally focussed solely on outreach, led to a new cost-effectiveness analysis and protocol for assessing flood-mitigation plans and inspired other physical models for use in education and water management.
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Pourpak, Hamid, Bernard J. Bourbiaux, Frédéric Roggero, and Frederick Delay. "An Integrated Methodology for Calibrating a Heterogeneous/Fractured Reservoir Model From Wellbore Flow Measurements: Case Study." SPE Reservoir Evaluation & Engineering 12, no. 03 (May 31, 2009): 433–45. http://dx.doi.org/10.2118/113528-pa.
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Summary Reliable flow modeling of highly heterogeneous/fractured reservoirs necessarily goes through the calibration of poorly determined geological and/or petrophysical parameters to field flow measurements. To that end, optimization procedures based on gradient methods or on gradual-deformation techniques have been developed in recent years. This paper proposes a sequential method combining those two approaches. The case under consideration is a water-bearing reservoir constituted of heterogeneous, karstic and fractured limestones located near Poitiers, France. In a preliminary step, drilling, core, and log data acquired in approximately 30 wells were integrated into a geostatistical facies model used as the support for flow simulation. First the facies petrophysical properties of this model were calibrated to well pumping and interference responses within a gradient-based inversion loop. Flow responses could be reproduced, with the exception of a few "problematic" observation wells. Second the gradual-deformation method was applied, globally then locally, to improve the distribution of facies while keeping the previously optimized petrophysical properties. The problematic wells' responses could be reproduced better without altering the other wells' match. Furthermore, that good match of calibration wells was obtained on a simplified geostatistical model involving fewer facies than in the initial model. The gradual-deformation method then appears as a robust and effective approach to find a model best matching a set of flow data among equiprobable geostatistical models. To conclude, the sequential-modeling method demonstrated herein is an effective way to actually integrate geological and flow data and to link geosciences and reservoir-engineering skills, for setting up consistent models of hardly tractable highly heterogeneous reservoirs. Introduction During the past 20 years, the technique of mathematical modeling has been used extensively in the study of groundwater-resources management and aquifer remediation (Sun 1994). Concern was especially focused on fluid transfer in heterogeneous and/or fractured reservoirs. That resulted in conclusive advances in the characterization and modeling of fractured reservoirs (Cacas et al. 2001). Actually, wellbore information on underground reservoir heterogeneities and fractures (e.g., core descriptions, image logs, and production profiles) is now used to condition the geostatistical pixel-based models or the object-based stochastic models of these reservoirs and to calibrate the hydraulic properties of major flow heterogeneities such as fractures (Sarda et al. 2002). However, the problem of reservoir-model construction remains highly undetermined. The purpose of this paper is to design and validate an inversion method for calibrating the poorly defined flow models of highly heterogeneous reservoirs to wellbore dynamic data. The design and the application of that method are performed on an experimental hydrogeological site (EHS) settled on a karstic and fractured limestone aquifer located near Poitiers, France. The flow model is based on a geostatistical distribution of facies. The method involves two successive steps:the inversion of facies petrophysical properties andthe gradual deformation of the facies distribution. The resulting model is shown to predict well responses effectively. Finally, the possibility of further calibration improvement is investigated by means of alternative flow-modeling approaches, such as the use of a dual-porosity model or a more accurate modeling of conductive bodies.
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Ramadan, Elsayed M., Heba F. Abdelwahab, Zuzana Vranayova, Martina Zelenakova, and Abdelazim M. Negm. "Optimization-Based Proposed Solution for Water Shortage Problems: A Case Study in the Ismailia Canal, East Nile Delta, Egypt." Water 13, no. 18 (September 9, 2021): 2481. http://dx.doi.org/10.3390/w13182481.
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Water conflicts in transboundary watersheds are significantly exacerbated by insufficient freshwater sources and high water demands. Due to its increasing population and various development projects, as well as current and potential water shortages, Egypt is one of the most populated and impacted countries in Africa and the Middle East in terms of water scarcity. With good future planning, modeling will help to solve water scarcity problems in the Ismailia canal, which is one of the most significant branches of the Nile River. Many previous studies of the Nile river basin depended on quality modeling and hydro-economic models which had policy or system control constraints. To overcome this deficit position and number, the East Nile Delta area was investigated using LINDO (linear interactive, and discrete optimizer) software; a mathematical model with physical constraints (mass balances); and ArcGIS software for canals and water demands from the agriculture sector, which is expected to face a water shortage. Using the total capital (Ismailia canal, groundwater, and water reuse) and total demand for water from different industries, the software measures the shortage area and redistributes the water according to demand node preferences (irrigation, domestic, and industrial water demands). At the irrigation network’s end, a water deficit of 789.81 MCM/year was estimated at Al-Salhiya, Ismailia, El Qantara West, Fayed, and Port Said. The model was then run through three scenarios: (1) the Ismailia Canal Lining’s effect, (2) surface water’s impact, and (3) groundwater’s impact. Water scarcity was proportional to lining four sections at a length of 61.0 km, which is considered to be optimal—based on the simulation which predicts that the Ismailia canal head flow will rise by 15%, according to scenarios—and the most effective way to reduce water scarcity in the face of climate change and limited resources as a result of the increasing population and built-in industrial projects in Egypt.
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Sylvia, Novi, Meriatna Meriatna, Fikri Hasfita, and Lukman Hakim. "Optimasi Adsorpsi Ion Mg2+ pada Fixed Bed Column dengan Menggunakan Response Surface Methodology." Reaktor 17, no. 3 (October 3, 2017): 126. http://dx.doi.org/10.14710/reaktor.17.3.126-131.
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Abstract OPTIMIZATION ADSORPTION OF Mg2+ ION ON FIXED BED COLUMN USING RESPONSE SURFACE METHODOLOGY. Modeling of the adsorption process is used to establish the mathematical relationship between the interacting process variables and process optimization. This is important to determine the factor values that produce a maximum response. Adsorption of Mg from groundwater was optimized using response surface methodology based on Box-Behnken design was used to analyze adsorption data. The process was investigated by continuous experiments. Variables included in the process were: bed depths (7.5, 10, and 12.5 cm), time (20, 40, and 60 min), and flow rate (6, 10, and 14 L/min). Regression analysis was used to analyze the developed models. The outcome of this research showed that 72.784% of the variability in removal efficiency is attributed to the three process variables considered, that is, bed depths, time, and flow rate. Optimization tests showed that the optimum operating conditions for the adsorption process occurred at a bed depth of 11.37 cm, time of 55.53 min and flow rate of 6 L/min. Keywords: adsorption; Box-Behnken design; magnesium (Mg2+); optimization AbstrakPemodelan dari proses adsorpsi digunakan untuk menentukan hubungan matematis antara variabel proses interaksi dan proses optimasi. Hal ini penting untuk menentukan nilai faktor yang menghasilkan respon maksimum. Adsorpsi magnesium (Mg2+) dari air tanah dioptimalkan menggunakan metodologi respon permukaan model Desain Box-Behnken yang digunakan untuk menganalisis data adsorpsi. Percobaan dilakukan secara kontinyu. Variabel yang termasuk dalam proses tersebut adalah: tinggi unggun (7,5, 10 dan 12,5 cm), waktu kontak (20, 40, dan 60 menit), dan laju alir (6, 10, dan 14 L/menit). Analisis regresi digunakan untuk menganalisis model yang dikembangkan. Hasil penelitian menunjukkan bahwa 72,784% efisiensi penyisihan Mg2+ ditentukan oleh tiga variabel proses, yaitu tinggi unggun, waktu kontak, dan laju alir. Hasil optimasi menunjukkan bahwa kondisi operasi optimum untuk proses adsorpsi terjadi pada tinggi unggun 11,37 cm, waktu kontak 55,53 menit dan laju alir 6 L/menit. Kata kunci: adsorpsi; Box-Behnken desain; magnesium (Mg2+); optimasi
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Hunter, Jason M., Holger R. Maier, Matthew S. Gibbs, Eloise R. Foale, Naomi A. Grosvenor, Nathan P. Harders, and Tahali C. Kikuchi-Miller. "Framework for developing hybrid process-driven, artificial neural network and regression models for salinity prediction in river systems." Hydrology and Earth System Sciences 22, no. 5 (May 22, 2018): 2987–3006. http://dx.doi.org/10.5194/hess-22-2987-2018.
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Abstract. Salinity modelling in river systems is complicated by a number of processes, including in-stream salt transport and various mechanisms of saline accession that vary dynamically as a function of water level and flow, often at different temporal scales. Traditionally, salinity models in rivers have either been process- or data-driven. The primary problem with process-based models is that in many instances, not all of the underlying processes are fully understood or able to be represented mathematically. There are also often insufficient historical data to support model development. The major limitation of data-driven models, such as artificial neural networks (ANNs) in comparison, is that they provide limited system understanding and are generally not able to be used to inform management decisions targeting specific processes, as different processes are generally modelled implicitly. In order to overcome these limitations, a generic framework for developing hybrid process and data-driven models of salinity in river systems is introduced and applied in this paper. As part of the approach, the most suitable sub-models are developed for each sub-process affecting salinity at the location of interest based on consideration of model purpose, the degree of process understanding and data availability, which are then combined to form the hybrid model. The approach is applied to a 46 km reach of the Murray River in South Australia, which is affected by high levels of salinity. In this reach, the major processes affecting salinity include in-stream salt transport, accession of saline groundwater along the length of the reach and the flushing of three waterbodies in the floodplain during overbank flows of various magnitudes. Based on trade-offs between the degree of process understanding and data availability, a process-driven model is developed for in-stream salt transport, an ANN model is used to model saline groundwater accession and three linear regression models are used to account for the flushing of the different floodplain storages. The resulting hybrid model performs very well on approximately 3 years of daily validation data, with a Nash–Sutcliffe efficiency (NSE) of 0.89 and a root mean squared error (RMSE) of 12.62 mg L−1 (over a range from approximately 50 to 250 mg L−1). Each component of the hybrid model results in noticeable improvements in model performance corresponding to the range of flows for which they are developed. The predictive performance of the hybrid model is significantly better than that of a benchmark process-driven model (NSE = −0.14, RMSE = 41.10 mg L−1, Gbench index = 0.90) and slightly better than that of a benchmark data-driven (ANN) model (NSE = 0.83, RMSE = 15.93 mg L−1, Gbench index = 0.36). Apart from improved predictive performance, the hybrid model also has advantages over the ANN benchmark model in terms of increased capacity for improving system understanding and greater ability to support management decisions.
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Mahmood, Mohammed Shuker, and D. Lesnic. "Identification of conductivity in inhomogeneous orthotropic media." International Journal of Numerical Methods for Heat & Fluid Flow 29, no. 1 (January 7, 2019): 165–83. http://dx.doi.org/10.1108/hff-11-2017-0469.
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Purpose The purpose of this paper is to solve numerically the identification of the thermal conductivity of an inhomogeneous and possibly anisotropic medium from interior/internal temperature measurements. Design/methodology/approach The formulated coefficient identification problem is inverse and ill-posed, and therefore, to obtain a stable solution, a non-linear regularized least-squares approach is used. For the numerical discretization of the orthotropic heat equation, the finite-difference method is applied, while the non-linear minimization is performed using the MATLAB toolbox routine lsqnonlin. Findings Numerical results show the accuracy and stability of solution even in the presence of noise (modelling inexact measurements) in the input temperature data. Research limitations/implications The mathematical formulation uses temporal temperature measurements taken at many points inside the sample, and this may be too much information that is provided to identify a space-wise dependent only conductivity tensor. Practical implications As noisy data are inverted, the paper models real situations in which practical temperature measurements recorded using thermocouples are inherently contaminated with random noise. Social implications The identification of the conductivity of inhomogeneous and orthotropic media will be of great interest to the inverse problems community with applications in geophysics, groundwater flow and heat transfer. Originality/value The current investigation advances the field of coefficient identification problems by generalizing the conductivity to be anisotropic in addition of being heterogeneous. The originality lies in performing, for the first time, numerical simulations of inversion to find the orthotropic and inhomogeneous thermal conductivity from noisy temperature measurements. Further value and physical significance are brought in by determining the degree of cure in a resin transfer molding process, in addition to obtaining the inhomogeneous thermal conductivity of the tested material.
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Barfod, Adrian A. S., Troels N. Vilhelmsen, Flemming Jørgensen, Anders V. Christiansen, Anne-Sophie Høyer, Julien Straubhaar, and Ingelise Møller. "Contributions to uncertainty related to hydrostratigraphic modeling using multiple-point statistics." Hydrology and Earth System Sciences 22, no. 10 (October 24, 2018): 5485–508. http://dx.doi.org/10.5194/hess-22-5485-2018.
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Abstract. Forecasting the flow of groundwater requires a hydrostratigraphic model, which describes the architecture of the subsurface. State-of-the-art multiple-point statistical (MPS) tools are readily available for creating models depicting subsurface geology. We present a study of the impact of key parameters related to stochastic MPS simulation of a real-world hydrogeophysical dataset from Kasted, Denmark, using the snesim algorithm. The goal is to study how changes to the underlying datasets propagate into the hydrostratigraphic realizations when using MPS for stochastic modeling. This study focuses on the sensitivity of the MPS realizations to the geophysical soft data, borehole lithology logs, and the training image (TI). The modeling approach used in this paper utilizes a cognitive geological model as a TI to simulate ensemble hydrostratigraphic models. The target model contains three overall hydrostratigraphic categories, and the MPS realizations are compared visually as well as quantitatively using mathematical measures of similarity. The quantitative similarity analysis is carried out exhaustively, and realizations are compared with each other as well as with the cognitive geological model. The results underline the importance of geophysical data for constraining MPS simulations. Relying only on borehole data and the conceptual geology, or TI, results in a significant increase in realization uncertainty. The airborne transient electromagnetic SkyTEM data used in this study cover a large portion of the Kasted model area and are essential to the hydrostratigraphic architecture. On the other hand, the borehole lithology logs are sparser, and 410 boreholes were present in this study. The borehole lithology logs infer local changes in the immediate vicinity of the boreholes, thus, in areas with a high degree of geological heterogeneity, boreholes only provide limited large-scale structural information. Lithological information is, however, important for the interpretation of the geophysical responses. The importance of the TI was also studied. An example was presented where an alternative geological model from a neighboring area was used to simulate hydrostratigraphic models. It was shown that as long as the geological settings are similar in nature, the realizations, although different, still reflect the hydrostratigraphic architecture. If a TI containing a biased geological conceptualization is used, the resulting realizations will resemble the TI and contain less structure in particular areas, where the soft data show almost even probability to two or all three of the hydrostratigraphic units.
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Qin, Zhenggui, Yuan Wang, Yi Song, and Qi Dong. "The Analysis on Seepage Field of Grouted and Shotcrete Lined Underwater Tunnel." Mathematical Problems in Engineering 2020 (May 5, 2020): 1–15. http://dx.doi.org/10.1155/2020/7319054.
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Groundwater control in underwater tunnels by drilling and blasting method is generally carried out by grouting ring, shotcrete lining (primary lining), and concrete lining. The permeable grouting ring and shotcrete lining have an important impact on seepage field. However, the currently published research models of related results are for homogeneous and isotropic single-layer unlined tunnels, ignoring the important effects of tunnel grouting circles and primary lining. If the conclusions of the relevant literature are directly used to guide the tunnel design, large errors may occur. Therefore, on the basis of previous studies, this article extends the tunnel seepage research model and incorporates the tunnel grouting ring and primary lining into the research model. The research model is more in line with actual working conditions. Based on the principle of mirror method, the seepage field of a drainage tunnel in an infinite aquifer is superposed with that of a water supply tunnel in an infinite aquifer, and the analytical solution to the seepage field of an grouted and shotcrete lined underwater tunnel in a semi-infinite aquifer is obtained, which is further verified by numerical analysis and experiment. In addition, the influence of grouting ring and primary lining parameters on seepage field is discussed by using partial differential analysis. The results show that the seepage flow of tunnel can be significantly alleviated by either reducing the permeability coefficient of grouting ring and primary lining or increasing the thickness of grouting ring and primary lining, but the water pressure of grouting ring and primary lining will increase.
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McKeown, Chris, R. Stuart Haszeldine, and Gary D. Couples. "Mathematical modelling of groundwater flow at Sellafield, UK." Engineering Geology 52, no. 3-4 (April 1999): 231–50. http://dx.doi.org/10.1016/s0013-7952(99)00008-3.
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