Hydraulic Conductivity Coefficient Research Articles

Sustainable water–ecosystem management using the Bayesian network and variable relationship analysis

ABSTRACT Under the pressures of global climate change and human activities, the carrying capacity of water and soil resources in agricultural lands has decreased, and the traditional models of agricultural development are no longer sustainable. Land degradation, groundwater quality reduction and ecosystem instability are the consequences of agricultural development without considering sustainability indicators. This article aims to investigate the use of variable relationship analysis and Bayesian network methods to analyze and investigate the relationship between irrigation in agriculture and the sustainability of the groundwater ecosystem. Descriptive statistics of agriculture including cultivation pattern, time, precipitation, irrigation, and land slope were analyzed and combined with the simulated characteristics of groundwater including specific yield, hydraulic conductivity and hydrodynamic diffusion coefficients. Five crops of wheat, barley, paddy, alfalfa, and potato were studied to evaluate the effect of plants on the pattern of nitrate release due to irrigation and fertilization in agriculture. The results showed that managing the amount of fertilizer and the volume of irrigation can positively affect the nitrate distribution pattern in the groundwater even in a short period of time.

Experimental investigation of sandy soil stabilization using chitosan biopolymer

The performance of an environmentally friendly biopolymer synthesised from secondary resources to overcome the wind erosion of sandy soil was investigated in this study. The study employed a multi-scale approach to investigate the mechanical, erosional, and hydraulic properties of sandy soil. At the macroscale, experimental techniques such as unconfined and triaxial compression tests, permeability measurements, contact angle assessments, and wind tunnel experiments were utilized to characterize the bulk behavior of the soil. Concurrently, molecular dynamics (MD) simulations were conducted at the nanoscale to predict surface mechanical characteristics and elucidate chemical interactions at the molecular level. Results show that when the outer surface of the sandy particles is coated with a sparse concentration of biopolymer, the sandy aerosol inhibitory performance is significant even under extreme storm conditions reaching speeds of 140 km/h of storms. The study on the impact of biopolymer content, curing time, and curing conditions revealed that the addition of chitosan biopolymer has the ability to enhance the bonding between particles and significantly enhance the mechanical properties of sandy soil. The atomic insight from molecular dynamics reveals huge entanglement between sandy particles and biopolymer by Van der Waals interaction. The results of the Unconfined Compressive Strength test indicate that chitosan enhances the compressive strength of sand by up to 320 kPa. Additionally, the triaxial test demonstrated that the application of chitosan led to a 34.2 kPa improvement in the cohesion of sand. Furthermore, analysis of the permeability test results revealed a decrease in the hydraulic conductivity coefficient from 1.6 × 10^-6 m/s to 5.7 × 10^-7 m/s, representing a reduction of approximately 35 %.

Coupling of WetSpass-M and MODFLOW models for groundwater flow assessment

Recharge is considered a key parameter in groundwater models for sustainable management of aquifers, which is influenced by factors such as land use, soil and weather. The present study was conducted to couple WetSpass-M and MODFLOW models in the Neyshabur–Rokh Basin. To this aim, the simulated recharge by the WetSpass-M model was applied as an input into MODFLOW to assess the groundwater balance. The hydrodynamic coefficients were determined by calibrating the model, and the model sensitivity to the hydraulic conductivity coefficient, specific yield and recharge was evaluated. The results indicated that the annual average of surface runoff, actual evapotranspiration, interception and recharge during 1991–2017 equalled 18, 36, 7.6 and 42.6% of the average annual precipitation in the basin, respectively. The accurate alignment of simulated and observed water levels, along with the achievement of suitable evaluation criteria values in both steady and transient states, demonstrates the WetSpass-M model's precision in estimating recharge and successfully integrating the two models. The groundwater balance assessment revealed a significant deficit in the aquifer, with the model demonstrating greater sensitivity to the hydraulic conductivity coefficient and providing valuable insights for the sustainable management of the Neyshabur aquifer. Thematic collection: This article is part of the Monitoring the aquifers collection available at: https://www.lyellcollection.org/topic/collections/monitoring-the-aquifers

Comparison between MODFLOW Groundwater Modeling with Traditional and Distributed Recharge

Groundwater models serve the function of predicting and analyzing aquifer behavior. They require input information, such as hydrogeological parameters like hydraulic conductivity and storage coefficient, which are used to calibrate the model, and elementary actions that include recharge and extracted volumes. There are cases in which it is insufficient to know the homogeneous recharge entering through the surface basin, referred to as traditional recharge, since, in many instances, the distribution is altered by changes in land use. For this reason, based on the geomorphological characteristics of the basin, weighting is proposed for sites with greater recharge capacity. The present work shows a solution to the recharge distribution using the potential groundwater recharge (PGR) map, which is formed by weighting spatially distributed information: (i) drainage, (ii) precipitation, (iii) land use, (iv) geological faults, (v) soil type, (vi) slope, and (vii) hydrogeology. A comparison is made between groundwater modeling using traditional recharge and PGR recharge. It is noted that the modeling perform similarly for both recharges, and the errors do not exceed 5% absolute error, which validates the model’s reliability. This manuscript demonstrates how to model and calibrate groundwater in aquifers with scarce information and variable recharge, making it reproducible.

Experimental Study on Solidified Lake Sediment Based on Industrial Solid Waste and Construction Waste: Stabilization and Mechanism

Occupation of land and damage to the surrounding ecosystem may occur due to the accumulation of dredged lake sediments. In order to solve the large amount of dredged lake sediments, industrial wastes (slag, desulfurization gypsum) and urban construction waste were used to solidify the lake substrate, obtained a new construction material. Water content, volumetric shrinkage, unconfined compressive strength and flexural strength parameters and hydraulic conductivity coefficients of the solidified sediment were obtained from water content determination tests, volumetric shrinkage tests, unconfined compressive strength tests, flexural tests and permeation tests. Mineralogical composition and microstructural characterization of the solidified sediment using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) were obtained. The solidification mechanism of lake sediment under the coupling of industrial waste and urban construction waste was revealed. The water content of the specimens decreased rapidly, and shrinkage deformation occurred in curing for 7 d. The volumetric shrinkage of 28 d was eventually maintained at 1.27–5.19%. The trend of specimen strength changed with the extension of time in the overall increase state, the compressive strength and flexural strength within 28 d were 3.15–10.96 MPa and 0.64–2.69 MPa, respectively. The solidified sediment material showed excellent anti-seepage performance, the hydraulic conductivity reached stability at 1.22 × 10−8–55.4 × 10−8 cm/s. Gismondine, gypsum, calcite, scawtite and fibrous C-S-H phases were generated in the solidified material.

Material characteristics and pollutant diffusion simulation of cutoff walls made of alkali activated slag/bentonite

To prevent heavy metal pollution, vertical cut-off walls made of cement soil are often used as barriers. This article developed a cementitious material with a “low-carbon footprint” (alkali activated slag) to replace cement. The performance of alkali activated slag soil and cement soil was comprehensively explored through unconfined compressive strength, hydraulic conductivity, Zn2+ adsorption, and chloride ion diffusion tests. And the micro pore structure and micro morphology characteristics of the cutoff wall were explored through nuclear magnetic resonance testing and scanning electron microscopy testing. Finally, considering the normal distribution of pollutants, the diffusion process of pollutants in the transition layer, cut-off wall and aquifer is simulated by using the COMSOL Multiphysics 5.6. Research has found that alkali activated slag soil meets the requirement of low permeability in the early stage of maintenance, making up for the shortcomings of cement soil maintenance in the early stage. After adding bentonite to alkali activated slag soil, it was found that the hydraulic conductivity and effective diffusion coefficient showed a decreasing trend, while the adsorption rate of Zn2+ was significantly increased. Due to the double layered structure of bentonite and the hinge of C-A-S-H generated by alkali activated slag, it promotes an increase in the proportion of small pores and the generation of free water with poor fluidity, thereby improving the blocking effect of the cut-off wall on pollutants. Through simulation results, it was found that the breakthrough time of alkali activated slag soil as a cutoff wall is 3.07 times that of cement soil. After adding 6% and 12% bentonite to the alkali activated slag soil, the breakthrough time of the cut-off wall increased by 1.74 times and 4.25 times, respectively.

Assessing relevant transport processes in Opalinus Clay at the Mont Terri rock laboratory using excess-pressure, concentration and temperature profiles

In the context of studies on deep geological disposal of radioactive waste, the overpressures whose origin is still debated raise the question of the relevant transport processes to be taken into account in clay media. An anomaly of about 13 bars was identified during the Deep Borehole (DB) experiment at the Mont Terri URL (Switzerland) whose objective was to identify the impact of hydraulic and chemical transient behavior on fluid and solute transfers. The first stage of DB experiment consisted in drilling BDB-1, a 250 m long-inclined borehole across the entire Opalinus Clay (OPA). The second stage of the work aimed at determining the driving forces (pressure, temperature, and salinity gradients) and transport coefficients (diffusion, hydraulic conductivity, chemical and thermal osmotic coefficients) using a multi-packer hydraulic system. The last step of this fully experimental and modelling integrated study was the development of 1D transport models either in fully transient or in pseudo-steady state to reproduce the measured pressure and salinity profiles. Pure hydraulic calculations evaluated a Darcy velocity in the order of 10−14 m s−1, related to a downward flow. However the best agreement with the data was obtained by introducing osmotic processes. Chemical osmosis slightly increased the advective flow in the same direction, but its effect is minor compared to that of thermo-osmosis which inverts the water movement with a mean Darcy velocity of about 10−13 m s−1. However, the Peclet number still confirmed the dominance of diffusion with respect to advection at Mont Terri.

Variation of the Hydraulic Conductivity and the Mechanical Characteristics of Plastic Concrete with Time

Sand-bentonite-cement are commonly used as cut-off walls to isolate polluted soils or in ground improvement technologies and as retaining structures as secant pile wall. In this research, a laboratory program consisted from 105 sample were prepared and tested between different tests, such as hydraulic conductivity, porosity, and compressive strength to monitor the mechanical behavior of sand-bentonite-cement at different ages. Based on the experimental relationships between hydraulic conductivity coefficient and samples age; there were reduction due to added bentonite to mixture reach about 35.0% at 7 days. Moreover, the average reduction in the compressive strength of plastic concrete samples with bentonite was lower by average range about 51.0% than the compressive strength of plastic concrete samples without bentonite at 7 days. In this study, proposed formulas were derived to estimate the splitting tensile strength based on the compressive strength and the hydraulic conductivity in terms of the bentonite/cement ratio and testing age. The predicted values showed well agreement with the experimental records for samples of sand-bentonite-cement mixtures where the standard deviation and coefficient of variation were 0.02, and 0.94%, respectively.

Delineation of preferential flow pathways in a tropical crystalline rock aquifer in Tarkwa, Ghana using integrated hydrogeophysical methods

Abstract In Ghana, crystalline rock aquifers with secondary hydraulic features and preferential flow pathways serve as very important aquifers. Protecting and managing these geological porous media require identifying preferential flow pathways and hydraulic characteristics. In this study, preferential flow pathways and hydraulic parameters were characterised for two boreholes (Hilly and Valley) located in Tarkwa, Ghana via the integrated use of borehole dilution testing (BDT), slug testing, and geological mapping. The geological fieldwork mapped a relatively sparsely fractured Sandstone Unit overlying a heavily foliated and fissile Phyllite Unit. Geology influenced groundwater flow in boreholes. The BDT confirmed the geology by showing a stratified flow system with preferential flow pathways. The Hilly/recharge area borehole shows relatively low downward flow, whereas the Valley/transition area borehole is dominated by the concentrated diffuse horizontal flow. These flow patterns are in agreement with the borehole locations and their dominant geologies. The estimated hydraulic conductivity, transmissivity, and storage coefficient ranged between 5.1 × 10−4–7.7 × 10−2 m/d, 4.0 × 10−2–3.2 m2/d, and 10−7–10−5, respectively. The cheap integrated hydrogeophysical methods used in this study are applicable for characterising, protecting, and managing other crystalline aquifers in the West African sub-region and other tropical terrains.

Qanat's hydraulic harim determination using the meshless numerical method

Abstract Qanat is an ancient water harvesting technology which is used for irrigation, agriculture and drinking in many countries of the world. A key element of preserving this heritage is calculating their protection area. In this study, the main aim is depiction of the hydraulic harim of qanat with the usage of the meshless numerical method. Afterward, the qanat package has been added to this model to delineate the hydraulic harim of the qanat. Two qanat systems are shown here: one in a standard aquifer and the other in a real test case, namely Haji-Abad qanat, located in the Birjand unconfined aquifer. In the real test case, the hydraulic harim of Haji-Abad qanat with 10 collection shafts is depicted in 3 time sections as well. The time sections are 3 years after extraction (2014), 6 years (2017) and 11 years (2022). The findings stated that time makes the harim area larger. In addition, the hydraulic harim is extended to areas with a higher hydraulic conductivity coefficient. Ultimately, we have delineated the hydraulic harim for 2040 and unfortunately, it is influenced by buildings. Therefore, it is necessary to find the hydraulic harim of qanats in order to protect this traditional heritage.

Inverse modeling application for aquifer parameters estimation using a precise simulation–optimization model

In this research, a simulation–optimization (S/O) model is used in order to estimate aquifer parameters on two aquifers. In this model, meshless local Petrov–Galerkin (MLPG) is used for simulation purpose and modified teaching–learning-based optimization (MTLBO) algorithm is engaged as optimization model. Linking these two powerful models generates a S/O model named MLPG-MTLBO. The proposed model is applied on two aquifers: a standard and a real field aquifer. In standard aquifer, parameters are only transmissivity coefficients in x and y direction for three zones. The acquired results by MLPG-MTLBO are really close to true values. This fact presents the power of MLPG-MTLBO inverse model. Therefore, it is applied on field aquifer. Unconfined aquifer of Birjand recognized as real case study. Parameters which are needed to be estimated are specific yields and hydraulic conductivity coefficients. These parameters are computed by MLPG-MTLBO and entered to the groundwater flow model. The achieved groundwater table compared with observation data and RMSE is calculated. RMSE value is 0.356 m; however, this error criterion for MLPG and FDM is 0.757 m and 1.197 m, respectively. This means that estimation is precise and makes the RMSE to reduce from 0.757 to 0.356 m, and also, MLPG-MTLBO is an accurate model for this aim.

Bubble Coarsening Kinetics in Porous Media

AbstractBubbles in subsurface porous media spontaneously coarsen to reduce free energy. Bubble coarsening dramatically changes surface area and pore occupancy, which affect the hydraulic conductivity, mass and heat transfer coefficients, and chemical reactions. Coarsening kinetics in porous media is thus critical in modeling geologic CO2 sequestration, hydrogen subsurface storage, hydrate reservoir recovery, and other relevant geophysical problems. We show that bubble coarsening kinetics in porous media fundamentally deviates from classical Lifshitz‐Slyozov‐Wagner theory, because porous structure quantizes the space and rescales the mass transfer coefficient. We develop a new coarsening theory that agrees well with numerical simulations. We identify a pseudo‐equilibrium time proportional to the cubic of pore size. In a typical CO2 sequestration scenario, local equilibrium can be achieved in 1s for media consisting of sub‐micron pores, while in decades for media consisting of 1 mm pores. This work provides new insights in modeling complex fluid behaviors in subsurface environment.

Prediction of hydraulic conductivity of porous granular media by establishment of random forest algorithm

The present study investigates the possibility of using random forest (RF) algorithm for prediction of hydraulic conductivity of coarse-sized granular material. Meanwhile, the conventional soft computing methods named artificial neural network (ANN) and adaptive network-based fuzzy inference system (ANFIS) are considered to assess the robustness of the established approach. The characterized properties related to the particle size distribution as well as the air void content are utilized to predict the hydraulic conductivity coefficient. In addition, owing to the direct effect of the applied hydraulic head on the measured values of water flow velocity, the hydraulic gradient is also characterized as an influential parameter. The statistical comparison between the prediction capability of the RF and the results of ANN and ANFIS models corroborates the robustness of the developed procedure based on the machine learning algorithm to indirectly predict the hydraulic conductivity of the provided porous media. The results of parametric analysis mainly demonstrate that the air void content among aggregates is by far the most influential factor affecting the permeability of granular media made of coarse-sized aggregate.

A literature review on pumping test analysis (2000-2022).

Accurate and precise values of hydrodynamic parameters are needed for groundwater modeling and management. Pumping test in the aquifer is the standard method to estimate the transmissivity, hydraulic conductivity, and storage coefficient as the key hydrodynamic parameters. Analytical solutions with curve matching and numerical modeling are two methods to estimate these parameters in the aquifer. Graphical analyses are commonly applied to time-drawdown/water table data which are time-consuming and approximate. Graphical type-curve methods as promising tools are used extensively in water resources studies, while applying these methods is still new in pumping test analysis. In the current study, the first effort based on our knowledge, we have reviewed the literature type-curve graphical methods in pumping test analysis. To achieve this goal, we reviewed and compared the journal articles regarding the characteristics and capabilities of the modeling process from 2000 to 2022. We have clustered the reviewed papers into graphical, modeling, and hybrid categories. Then, a comprehensive review of the selected papers was presented to delineate the highlight of every paper. This review could guide researchers in pumping test analysis. Also, we have presented various recommendations for future research to improve the quality of hydrodynamic parameter estimation.

Energy conversion in Textus Bioactiv Ag membrane dressings using Peusner's network thermodynamic descriptions.

The Textus Bioactiv Ag membrane is an active dressing for the treatment of chronic wounds such as venous stasis ulcers and burns. Determination of the transport and internal energy conversion properties of the Textus Bioactiv Ag membrane using the Kedem-Katchalsky-Peusner model. This model introduces the coefficients Lij necessary to calculate the degree of coupling (lij, QL), energy conversion efficiency (eij), dissipated energy (S-energy), free energy (F-energy), and internal energy (U-energy). The research material was the Textus Bioactiv Ag membrane that is used as an active dressing in the treatment of difficult-to-heal wounds, and KCl aqueous solutions. The research methods employed Peusner's formalism of network thermodynamics and Kedem and Katchalsky's thermodynamics of membrane processes. To calculate the Lij coefficients, we used hydraulic conductivity (Lp), diffusion conductivity (ů) and reflection (ó) coefficients to perform experimental measurements in different conditions. The Lp coefficient for the Textus Bioactiv Ag membrane is nonlinearly dependent on the average concentrations of the solutions. In turn, the ů and ó coefficients are nonlinearly dependent on the differences in osmotic pressures (Äđ). An increase in the Äđ causes the Textus Bioactiv Ag membrane to become more permeable and less selective for KCl solutions. The coefficients of Peusner (Lij), couplings (lij, QL), energy conversion efficiency (eij), S-energy, F-energy, and U-energy also depend nonlinearly on Äđ. Our results showed that for higher concentrations of KCl solutions transported through the Textus Bioactiv Ag membrane, the coupling and energy conversion coefficients were greater for larger Äđ up to their maximum values for large Äđ. Coupling of the membrane structure with the electrolyte flux through the membrane is observed for Äđ greater than 10 kPa. Textus Bioactiv Ag membrane dressings possess the properties of a solution component separator as well as an internal energy converter.

Temporary clogging effects induced by a sustainable anti-icing hydrogel on the hydraulic conductivity and inertia coefficient of open-graded asphalt pavements

Open-graded asphalt pavements require special winter maintenance procedures to ensure the effectiveness of anti-icing and deicing measures. A recently developed solution for this type of pavement is represented by an environmental friendly thickened bio-based salt hydrogel, which consists of a thermo-sensitive sodium chloride (NaCl) brine admixed with a gellant agent (seaweed fibers) having the ability to form a gel-like structure when hot-sprayed on a cold surface. This thin salt layer results in a long-lasting residual efficacy of the winter maintenance product and in a reduction of salt consumption, but affects the drainage capacity of the pavement. These transient clogging effects were evaluated on laboratory-made specimens through the measurement of their vertical hydraulic conductivity variations before and after the hydrogel application, using a 1-D air permeameter and a constant head water permeameter. The analyses, based on Darcy–Forchheimer model and Darcy model for lower Reynold numbers, revealed a significant short-term reduction of the hydraulic conductivity, that, anyway, tends to be almost totally restored once the critical weather event is over (after about 6 h).

Hydraulic Characteristics of Dammam Aquifer in Sayed Al-Shuhadaa Agricultural city, Karbala- Iraq

This study's objective is to investigate the hydraulic properties of the Dammam aquifer utilizing three acceptable pumping wells for experimental pumping. The location under study is an agricultural project known as Sayed Al-Shuhadaa agricultural city, which is located in the Al-Ukhaidir section of the Ain Al-Tamar district, to the southwest of Razzaza Lake and west of the Holy Karbala province. Theis and Hantush methods had been applicated to analyze pumping test data. The ranges for transmissivity, hydraulic conductivity and storage coefficient are (111.3 - 1705.1) m2/day, (22.23 - 32.11) m/day, and (0.00075-0.0011) respectively. The agricultural city of Sayed Al-Shuhadaa was formerly a desolate desert, but it was transformed into an agriculturally productive region after (5000) donams of wheat were cultivated this season. The most important characteristic of this region is the use of pivotal irrigation systems of global origin, and the water source used in the farm is from the ground sea (groundwaterwater), as this source provides greater assurance of the sustainability of the farm's production, and aims to determine the hydraulic characteristics of the aquifer in the event that suitable wells are available for pumping tests. Calculating water excess and shortfall by performing the water balance. Assessing the appropriateness of groundwater for agricultural and irrigation purposes by analyzing its hydrochemical properties and quality. An attempt to implement a plan for agricultural groundwater management.

Hydrogeological Conditions and Mathematical Model of the Area Surrounding Hatra Suggested dam, Northwest Iraq

The area was hydrogeologically studied, it was found that the main aquifer is unconfined, it is located within Fat’ha Formation, and the hydraulic properties of this aquifer were also studied from the analysis of pumping tests data to determine the averages of transimissivity (T=671.027 m2/day), hydraulic conductivity (K=45.449 m/day), and storage coefficient (Sc=0.226). The groundwater levels and flow direction map was drawn, and it was found that the flow corresponds to the topographical slope of the land surface towards Tharthar valley, from the east - west towards the center of the study area, with a slight slope towards the south.These are some data represent a database that can be used in the design of the proposed dam on Tharthar valley, and the policy of storage and water management in the dam, reservoir as well as to build a mathematical model to predict the future behavior of groundwater in the region.Especially under the body of the dam to simulate the changes in groundwater conditions in the area of the small Hatra Dam Suggested on Tharthar valley, when storing water in front of a dam, and the expected engineering problems that would occur due to groundwater seepage under or on both sides of the dam body, by raising the water level within the valley – hypothetically, by 1m, 2m, 3m, 4m, 5m, 7m, 9 m and 11 m, assuming no pumping from the Aquifer during the rise of the level in the valley. as well as re-calculation with the same ranges of raising the level on another assumption, which is pumping from the wells in the area by 9 m3/ hour, for a period of time 6 hours per day, and determining the affected area by raising the level for each of the cases. The study indicated that the expected effect on the groundwater level starts when raising the water level inside the valley to four meters, and the clear increase continues at five meters, but the cumulative effect of raising the level from (7-11)m is slight. It also identified the sites that would allow the underground water to be pumped under the dam’s body, and the results were consistent with the geological reality of the area. These results will help in establishing an appropriate design for the foundations and structure of the dam.The current study is one of the requirements for building a small dam within the plan for managing water resources and developing the region that suffers from desertification, drought and environmental degradation.

Simulating Quar-Maharlu Aquifer in Fars Province, Iran, and Optimizing Artificial Recharge Using PMWIN Model

Background: The improper exploitation of water resources by humans has disrupted the natural balance of groundwater. Given the water resources restriction, it is crucial to manage these resources properly, recognize the current situation, and anticipate the harvesting or feeding effects. In this regard, simulators or models can act as valuable tools. Methods: In this research, we performed quantitative modeling of groundwater flow in the Quar-Maharlu plain, Fars Province, Iran using the PMWIN software. The model included three years’ calibration (2011-2014) for hydraulic conductivity coefficient and one year’s verification (2014-2015). To evaluate the model error in calibration and verification, the root mean square deviation (RMSD) was used. After simulating the aquifer to optimize the artificial recharge location by the flood spreading method, different scenarios were defined and examined by considering the natural and artificial factors. Results: The RMSD values for calibration were 1.55, 1.49, and 1.56 m for 2011, 2012, and 2013, respectively. The RMSD for verification of one year was 1.77 m, indicating the acceptable ability of the model to predict groundwater flow parameters. The stock variation for the whole aquifer was -8.88 mm3 in 2014. In the next step, the best recharging location was selected to create the maximum head increase (5.3cm) in the entire area of the plain. Conclusion: One of the effective ways to offset the negative balance is to strengthen the aquifer through artificial recharge.

Defect-deferred correction method for the non-stationary coupled Stokes/Darcy model

This paper develops the defect-deferred correction method to solve the non-stationary coupled Stokes/Darcy model. This method is a combination of defect correction method and deferred correction method. And it can not only achieve the second order accuracy in time, but also be applied to the problem with small viscosity and hydraulic conductivity coefficients. The theoretical proof of the stability and the second order accuracy in time are shown. Some numerical experiments are given to verify the error convergence order in time. In addition, compared with the standard Galerkin finite element method, the advantages of the presented method in calculating small viscosity and hydraulic conductivity coefficients will also be reflected in the numerical experiments.