Visual MODFLOW Research Articles

Artificial recharge to groundwater using geospatial and groundwater modelling techniques in North Western Himalaya, India

Artificial recharge to groundwater is an important process for the management of surface and subsurface water resources. In the present study suitable sites for artificial recharge to groundwater were delineated using geospatial techniques and groundwater modelling in Jammu Himalaya, India. Different thematic layers were prepared from remote sensing data (IRS-P6 and LISS-IV), and SRTM-DEM and aquifer parameters thematic layers were prepared from pumping test data and well inventory data collected during the field observations were integrated using the weighted index overlay method in the GIS environment to prepare the artificial recharge zone map. Further, suitable sites for artificial recharge map were determined by superimposing a drainage network map over the artificial recharge zones map, considering the terrain and local conditions for artificial recharge. The groundwater modelling for artificial recharge to groundwater was also carried out using Visual Modflow Flex software to determine the modeling zones for artificial recharge to groundwater. The lithologs data, aquifer thickness, hydraulic conductivity, specific yield and water level data were used to generate simulations of groundwater modelling zones. Finally, GIS based artificial recharge zones map and groundwater modelling zones were compared to validate artificial recharge zones. Simultaneously, a case study was also carried out to determine the impact of discharge and artificial recharge to surrounding aquifers. The results achieved from the current research proved the efficiency of geospatial technology and groundwater modelling techniques for delineating suitable zones and sites for artificial recharge to groundwater and their implementation in the field.

Pemodelan airtanah dan Neraca Airtanah Dampak Penambangan Batubara Open Pit pada Lipatan Sinklin di Daerah Muara Lawa, Kabupaten Kutai Barat, Provinsi Kalimantan Timur

Ch a n g e s in land use impacts on groundwater availability both in quality and quantity. Study of geological, hydrogeological conditions, hydrological, hydrogeological boundary conditions contribute to determine the presence of groundwater in the groundwater basin and determine the natural groundwater flow modeling patterns. Location of the study are in Muara Lawa, including the formation Pulaubalang, Pamaluan, and Balikpapan on Lampanan syncline structure. Exploration drilling results indicate, that the hydrogeological study area into the aquifer system of folded sedimentary rocks consisting of seven aquifer layers alternating between akuitar, aquifers, and the base layer in the form of akuiklud. The area bounded by the limits of the model study of surface water in two major rivers, the Lawa River (east) and the Perak River (west), as well as the groundwater divide with the highest head (north and south. The results of the analysis of the type of regional aquifers aquifer models including the category of semi depressed with aquitards dominance in the surface layer. The pattern of groundwater flow and head height can be predicted by modeling using Visual Modflow. There is an increase zone budget is almost five times higher than the natural condition to the active mining conditions, particularly in the green zone, that of the natural conditions of 1,502 m3 day-1 to 12,930 m3 day-1 in the active mining. This is due, in the mining area there is a change in land use and hidrostratigrafi, namely the formation of pits that reach depths of 70 meters.

Feasibility Study of Riverbed Filtration Technique at Sungai Kampar Perak by using Numerical Modelling

Population growth will result in the increase of water supply demand. Riverbed filtration or radial collector well technique is one of the options for increasing the water supply. Drainage Package of Visual MODFLOW was used for the riverbed filtration modelling. The modelling aimed to identify the optimum pumping rates withdrawal in order to fulfill Lembaga Air Perak requirement for additional water supply. Installation of radial collector wells in the depth of 10-12 m aquifer thickness at Sungai Kampar Perak would increase the supply of clean water for future water demand. The design of riverbed filtration technique consists of 4 m radius of collector well with depth of 10.54 m and five radials wells with 40 m length across the riverbed. Transient condition of the groundwater flow modelling result showed that the optimum pumping rate can meet the water supply requirements of about 35 MLD (35000 m3/day).

Monitoring regional groundwater flow and contaminant transport in Southern Punjab, Pakistan, using numerical modeling approach

A three-dimensional groundwater flow model was developed using Visual MODFLOW to characterize the groundwater regime and simulate groundwater flow behavior in Multan District of Pakistan from 1962 to 2015. The multi-layered model was calibrated in which arsenic concentration was used as a point source for solute transport modeling in the flow domain. The model calibration indicated a close agreement between the simulated and observed head values achieving residual mean value of 0.1 m and a correlation coefficient (R) value of 0.9 during the steady-state condition. The study revealed a gradual rise in groundwater levels from 1972, i.e., at a rate of about 0.08 m/year followed by a gradual decline after 1990 at a rate of about 0.39 m/year likely due to overexploitation of groundwater. The other reasons of depletion of the aquifer may include lesser natural recharge due to reduction in canal command area and increasing water demand and pumpage due to growing urban/rural development. The findings of contaminant transport modeling depicted flow path representation of arsenic movement mostly towards the rivers in the model domain. Overexploitation of groundwater needs to be controlled for effective development of groundwater resource, and proper purifying/filtering techniques have to be adopted to ensure safe groundwater use in the area.

Hydraulic performance evaluation of a quasi-two dimensional constructed wetland microcosm using tracer tests and Visual MODFLOW simulation

Hydraulic conditions of constructed wetlands (CWs) are crucial to pollutant removal and are influenced by factors such as influent loading rates, influent or effluent position or porous media size. The performance evaluation of CWs in real application, however, is difficult and a visualization analysis is difficult due to the black-box effect. In this paper, a nonopaque microcosmic horizontal subsurface flow constructed wetland (HSSFCW) reactor was built in the laboratory for an efficient and intuitive assessment of the influences of such parameters on the hydraulic performance of CWs. Chloride tracer tests were carried out to obtain parameters on hydraulic performance by considering hydraulic loading rates and different flow inlet-outlet configurations, while dye tracer tests were designed for the visualization of solute transport and diffusion. In parallel, an identical design of the HSSFCW reactor was modeled using the Visual MODFLOW (VM) software in order to detect the tracer movement and solute concentration field. Results show that the inflow rate and the inlet-outlet configuration have significant impacts on the hydraulic performance of a CW influencing RTD curve shape, flow path, dead zone distribution and hydraulic efficiency. The dead zone and flow path have been visualized and analyzed by comparing the dye tracer experiments of VM solute concentration field and particulate path-line tracking. In addition, the feasibility and reliability of the VM simulation has been verified. The application of VM in this study has been robust indicating a possible application for further investigations on the influencing factors of real CWs.

Analysis of Ground Water Head for Steady and Transient Conditions and Optimization of Pumping Rates using Visual MODFLOW 4.1

Analysis of Ground Water Head for Steady and Transient Conditions and Optimization of Pumping Rates using Visual MODFLOW 4.1

Analysis of rainfall infiltration and its influence on groundwater in rain gardens.

The dynamic observation data on groundwater level and water quality were obtained from rain gardens #2 and #3 from May to October 2016. The water balance method and 2D numerical simulation of variable saturation zone were used to calculate rainfall infiltration recharge coefficient, water supply, and evaporative discharge of rain garden. These parameters were used to simulate and explore the impact of rainfall infiltration in rain gardens on groundwater level and water quality. The groundwater depth of rain gardens was mainly affected by the concentrated infiltration of rainfall. The variation range of groundwater depth was approximately 4.298 ± 0.031mm for J1, 3.9364 ± 0.097mm for J2, and 4.0958 ± 0.064mm for J3, and the specific yield was 0.208. Groundwater quality was naturally attenuated and would not threaten the safety of groundwater at a certain scale. Visual MODFLOW was used to simulate groundwater flow and conduct parameter sensitivity analysis to determine the main influencing factors of garden groundwater level change. Results showed that rainfall recharge was crucial to module sensitivity.

Stability of Irrigation Canal Slopes Considering the Sea Level Rise and Dynamic Changes: Case Study El-Salam Canal, Egypt

Stability of canals slopes are of paramount importance in engineering works due to its interaction with the infrastructure including roads networks and buildings. The failure of these slopes could cause human disaster, catastrophic environmental, and economic losses. The present study aims to investigate the stability of canals slopes considering the climate changes through sea level rise, fluctuation of groundwater level and the seismic actions. The study was simulated on the North Eastern part of Nile Delta aquifer, Egypt using the finite difference code of Visual MODFLOW. Moreover, the groundwater flow under the effect of sea level rise was investigated to study its effect on slope stability of El-Salam Canal, Egypt. Furthermore, the finite element program of Phase 2 was implemented, and safety factors were calculated using the shear strength reduction method (SSRM). The models are calibrated and verified through experimental work using permeability and seepage model. Moreover, the two models were applied on El-Salam Canal considering three scenarios to identify the safety factors including the effect of sea level rise (SLR), earthquake acceleration and a combination of the two scenarios. The results indicated that dynamic response values of the canal slope have different variation rules under near and far field earthquakes. Finally, the damage location and pattern of the slope failure are different in varying groundwater conditions.

Dynamic changes of groundwater storage and flows in a disturbed alpine peatland under variable climatic conditions

Climate change and gullies (and ditches) on peatlands are well known factors altering peat hydrology. Yet, exactly how this alteration emerges from interaction of these factors with groundwater dynamics is still not fully understood. In this study, we tackled this issue by coupling field measurement with model simulation using Visual MODFLOW. Groundwater processes and the associated water budget during five months of the wet season, 2017 were examined in the Zoige peatland, located on the northeastern side of Qinghai-Tibet Plateau, China with elevations of 3400–3900 m. Simulations were performed for a peatland area of 3.89 × 104 m2 and three sub-zones within it representing peatland with no gullies (NG), a deep gully cutting through the peat layer (CT), and a shallow gully whose bed is within the peat layer (NCT). Model input parameters were calibrated and validated using the field-measured data. Modeling outcomes led to water budget showing relative contributions of main hydrological pathways (MHPs) (i.e., precipitation (P), evapotranspiration (ET), gully, groundwater flow, and boundary) to changes of water storage in peats (ΔS). Although these MHPs varied differently during rain and inter-rain periods, ΔS values were mainly controlled by the oscillated trend of the difference between P and ET. Variations of MHPs caused by NCT and CT were secondary to those due to those of P and ET during the wet season referred to as the short-term climate change. Vertical groundwater (VGW) flows were strongly correlated with water table (WT) levels in both rain and inter-rain periods, but their directions had different patterns in the two periods. Horizontal groundwater (HGW) flows tended to move into the deep (CT) gully, while move from the shallow (NCT) gully to the neighbor peats during both periods. Since HGW flows were about ten times greater than VGW ones, their effect on ΔS was significant during the long dry season. This would lead to continuous loss of groundwater stored in peats, demonstrating the coupled effect of long-term climate change and gullies on ΔS. These findings underline the necessity of controlling gully development and avoiding ditch excavation in future Zoige peatland management practices.

Research on the Role of Visual Modflow in Numerical Simulation of Groundwater

Research on the Role of Visual Modflow in Numerical Simulation of Groundwater

Validating Visual Modflow Numerical Model to Predict Future Impact of Brine Disposal on Groundwater

The aim of this research was to simulate the brine disposal fate within an aquifer. The Visual MODFLOW numerical code was used to predict the salt concentration emigration over time in an aquifer. The model was calibrated using laboratory experimental data. The model results revealed that there is an acceptable agreement between the observed and simulated data.

An environmental forensic investigation at a bio-medical waste treatment and disposal facility in Kerala, India

Indian statutes identify twelve different types of biomedical wastes and give the treatment and disposal options for each. Since it is not possible for every generator of biomedical waste to go for their own treatment and disposal facility, the small-scale generators take the service of centralized treatment and disposal facilities available to them on payment. In the state of Kerala in India, where the basic health indicators match those of many developed countries, the centralized biomedical waste treatment facility is run by Indian Medical Association (IMA), Kerala, under the banner IMAGE (IMA Goes Eco-Friendly) at a place called “Kanjikode” in the Palakkad District. The facility receives biomedical waste from around 4500 hospitals across the State and an equal number of medical laboratories. The plant incinerates the incinerable waste and the other kind of waste are disinfected and decontaminated. The residual ash and dried sludge are then moved to the landfill area. Recently, the facility was in the middle of a controversy due to the alleged health hazards it posed to the surrounding population. An environmental forensic investigation was carried out at the site to establish the merits of the allegation. The reported study is a part of the investigation where groundwater was analysed for the presence of heavy metals. As the biomedical waste contain heavy metals like Zn, Pb, Cd, Cr, and Hg, the presence of these were analysed to establish contamination of groundwater by the facility. The study area is bounded by Malampuzha dam and Korayar river. Groundwater contaminant transport modelling was done for a 3430 m × 3960 m area surrounding the waste treatment facility using Visual MODFLOW and MODPATH. Ground water flow direction and particle pathlines were computed to track the movement of contaminants. Groundwater samples were collected from the area shown to be polluted by the model, if metals were discharged by the facility, and also from outside this area. Water samples were collected conforming to the guidelines in the “Pollution Crime Forensic Investigation Manual” published by INTERPOL. The collected water samples were tested for heavy metal concentration using atomic absorption spectroscopy (AAS). The water sample analysis showed that the groundwater is not contaminated by heavy metal discharge from the biomedical treatment facility.

Potential evaluation of river bank infiltration along the Second Songhuajiang River

Based on the evaluation of the suitability for river bank infiltration along the Second Songhuajiang River and the basic geologic and hydrogeological conditions of the study area, the hydrogeological conceptual model and the corresponding mathematical model are established, and the numerical model of groundwater flow based on Visual MODFLOW is formulated. The drawdown of groundwater level of 1/3 of less than the aquifer thickness is taken as the criterion. By making the predicted groundwater flow field as close as possible to the flow field under the conditions of the permissible drawdown, the allowable exploitation quantity of groundwater under the condition of RBF along the Second Songhua River is obtained. The results show that under the conditions of the current year, the exploitation intensity of groundwater resources is small. However, under the condition of exploitation near the river, the groundwater exploitation potential of each suitable area is as high as 140×104 m3/d, and the allowable exploitation of groundwater is large under the annual precipitation frequency. The interaction of groundwater-surface water will be influenced, but there will be no side effects on the ecological function of the river.

Prediction of acid mine drainage formation and zinc migration in the tailings dam of a closed mine, and possible countermeasures

Acid mine drainage (AMD), the very acidic and highly contaminated leachate generated in closed/abandoned mines, is commonly managed by neutralization to raise the pH and precipitate most of the heavy metals. Although effective, this approach does not generate any product of economic value, so it is very costly and unsustainable in the long-term. Unfortunately, there are currently no effective alternatives to neutralization, and one way to improve the sustainability of this process is to reduce the volume of AMD generated and/or the concentration of heavy metals. The tailings dam investigated in this study is located in northern Hokkaido, Japan. Detailed characterization of borehole core samples showed that even after almost 40 years of exposure to the environment, the tailings still contain pyrite (FeS2) and substantial amounts of copper (Cu) and zinc (Zn). Reactive-transport modeling using Visual MODFLOW predicted that AMD quality would likely continue to deteriorate with time and that treatment should be continued for at least 1,000 years. The model also predicted that a barrier with low permeability installed downstream of the tailings dam or ground sealing techniques for recharge reduction could lower the volume of AMD and concentration of Zn from the site.

Fine Prediction for Mine Water Inflow on Basis of Visual Modflow

Mine water inflow refers to the influx of mine within the mine construction and production process of water per unit time. The amout of water inflow is not only an important indicator of the technical and economic evaluation of mine construction and rational development but also the main basis for coal mining production design department to develop programs to identify and develop the ability to mine dewatering and drainage measures, playing an important role in preventing the accidents of mine water inrush and flooding mine malignant as well as reducing the production costs and protecting mine safety. In this paper, the way coal mining in northeast in china for points, by means of sequence numerical simulation compared to traditional separated mining area in calculating water inflow, then matches the results to the existing mine water inflow, to validate the model accuracy, improve the accuracy of the numerical simulation, to provide security for mining coal mine safety.

Simulation of saltwater intrusion into coastal aquifer of Nagapattinam in the lower cauvery basin using SEAWAT

The groundwater that represents 30.1% of the global freshwater supplies is at risk of being contaminated by saltwater intrusion. Saltwater intrusion is the induced flow of seawater into freshwater aquifers. Saltwater intrusion can occur due to natural processes as well as over-extraction of groundwater from coastal aquifers. Growing urban populations in the coastal regions and thus a higher demand for freshwater, emphasise the importance of proper management of these aquifers and prevention of saltwater intrusion by over-extraction. Numerical modelling is a useful tool in helping hydrologists to understand and predict how saltwater intrusion occurs in coastal aquifers. There are various numerical models that can predict groundwater flow and contaminant transport such as SUTRA, SEAWAT, FEFLOW and MODFLOW. These numerical models are based on the governing equations of groundwater flow and contaminant transport. In this paper, the extension of saltwater intrusion into the coastal aquifers of the Nagapattinam coastal region, Tamil Nadu has been investigated by modelling the region using SEAWAT engine in Visual MODFLOW.

A groundwater flow model for the Wolin Island area, including glaciotectonic deformation

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.

Modelling groundwater flow and nitrate transport: a case study of an area used for precision agriculture in the middle part of the Vistula River valley, Poland

Abstract The present paper discusses studies related to the preparation of a hydrogeological model of groundwater flow and nitrate transport in an area where a precision farming system is applied. Components of water balance were determined using the UnSat Suite Plus software (HELP model), while the average infiltration rate calculated for the study area equalled 20 per cent. The Visual MODFLOW software was used for the purpose of modelling in the saturated zone. Hydrogeological parameters of the model layers, inclusive of hydraulic conductivity, were defined on the basis of results of column tests that were carried out under laboratory conditions (column experiment). Related to the dose of mineral nitrogen used in precision fertilisation (80 kg N/ha), scenarios of the spread of nitrates in the soil-water environment were worked out. The absolute residual mean error calculated for nitrate concentrations obtained from laboratory and modelling studies equalled 0.188 mg/L, the standard error of the estimate equalling 0.116 mg/L. Results obtained were shown graphically in the form of hydroisohypse maps and nitrate isolines. Conclusions were drawn regarding the possibility of using numerical modelling techniques in predicting transport and fate of nitrates from fertilisers applied in precision agriculture systems.

Indication of Groundwater Contamination Using Acesulfame and Other Pollutants in a Rural Area of Korea

Approximately 40,000 chemical products are currently used in Korea; these products can contaminate the groundwater/soil, the surrounding environment, and organisms for extended periods of time. In this study, a hydrological field survey, a water quality analysis, and groundwater modeling were performed to identify the source and transport path of pollution that was caused by inorganic matter and artificial sweeteners, especially acesulfame, in the groundwater of an agricultural area in Chungnam Province, Korea. In the study area, a higher concentration of acesulfame displayed a spatial distribution similar to nitrate-nitrogen concentration. The characteristics of the groundwater flow and the distribution of the acesulfame were simulated using the Visual MODFLOW Classic Interface ver. 2014.1 and the MT3DMS module, respectively. The modeled area was divided into hilly (southern), residential (northwest), and agricultural (northeast) zones. The stream’s boundary was set to be the drainage channel in the southern hilly zone. From the simulation, we found that acesulfame spread actively from the source for 1–3 years before it reached equilibrium in the northern part of the model domain (the area downstream of the stream’s boundary). The concentration of acesulfame in the agricultural zone of the model domain decreased after five years, and it reached the steam boundary and residential zone within 10 years. After 10 years, most of the acesulfame was discharged from the agricultural zone and the hilly zone, while the concentration in the residential zone was approximately the same. Acesulfame is considered to be a potential indicator of man-made contamination for use in the management of groundwater quality.

Research on precipitation Simulation of Water-rich Subway Station based on Visual Modflow

Based on the foundation pit dewatering and recharge engineering of a subway station in Jinan City, the groundwater control technology of foundation pit engineering based on fluid-solid coupling is studied in this paper. With the measures of setting deep and shallow recharge wells and dewatering construction of foundation pit at the same time of dewatering and recharging, the actual foundation pit dewatering engineering is simulated by visual 3D groundwater flow simulation software Visual Modflow. The additional stress principle of soil is used to analyze the land subsidence. The software makes full use of the characteristics of flexible determination of well location, number of wells, well structure, water inflow, well diameter and so on in the foundation pit, and realizes the visualization, anticipation and verification of the design dewatering process at the same time. The reliability of the method is proved and a new way of dewatering design for foundation pit in the future is provided.