scholarly journals An analytical study of groundwater fluctuations in unconfined leaky aquifers induced by multiple localized recharge and withdrawal

2013 ◽  
Vol 15 (3) ◽  
pp. 394-407 ◽  
Keyword(s):  
Groundwater Flow ◽  
Numerical Models ◽  
Temporal Distribution ◽  
Neumann Boundary ◽  
Unconfined Aquifer ◽  
Flow Equation ◽  
Aquifer System ◽  
Fourier Cosine ◽  
Induced Flow ◽  
Vertical Leakage

<p>Commonly used analytical methods for assessing the effects of recharge and withdrawal on the groundwater flow system are based on an idealistic assumption that the aquifer&rsquo;s base is fully impervious. In reality, the hydrostratigraphic conditions are often complex and involve leakage induced flow between aquifer and the confining layers. In this study, a simple analytical procedure is presented for determining the spatial and temporal distribution of water head in an unconfined aquifer system due to multiple localized recharge and withdrawal at time-varying rates. A new transient function is introduced that can conveniently approximate the rising and recession limbs of any single recharge hydrograph. Solution of linearized two-dimensional groundwater flow equation under Dirichlet and Neumann boundary conditions is obtained using finite Fourier cosine transform with analytic inversion. The study has at least one clear advantage over the existing solutions that it accounts for the vertical leakage in water table buildup and drawdown analysis. A computational example demonstrates that the leakage induced flow plays an important role in recharge and withdrawal processes of unconfined aquifer system. The model results can be used for estimating aquifer&rsquo;s hydraulic properties and validation of numerical models.</p>

scholarly journals Hydrogeological Conceptual Model in the Middle of Randublatung Groundwater Basin

2021 ◽  
Vol 926 (1) ◽  
pp. 012078
Author(s):  
D L Setyaningsih ◽  
K D Setyawan ◽  
D P E Putra ◽  
Salahuddin
Keyword(s):  
Groundwater Flow ◽  
Conceptual Model ◽  
Unconfined Aquifer ◽  
Primary Data ◽  
Essential Information ◽  
Aquifer System ◽  
The North ◽  
Shallow Wells ◽  
Groundwater Basin ◽  
Constant Head

Abstract Randublatung groundwater basin is one of the groundwaters basins with massive utilization of groundwater pumping. However, the knowledge of the comprehensive hydrogeological system in this groundwater basin is limited, so this research aims to determine a comprehensive hydrogeological conceptual model of the Randublatung groundwater basin. The methodology was conducted by collecting secondary and primary data of deep and shallow wells to evaluate boundaries of pattern and direction of groundwater flow and develop the aquifer system’s geometry. The result shows that the groundwater flow boundaries are Grogol River in the west, Wado River in the East, Bengawan Solo river in the South as a river boundary, and Rembang Mountains in the North as a constant head boundary. Therefore, groundwater flows from the hills area to the Bengawan Solo River and the north as the river’s flow. Based on the log bor evaluation, the aquifer system of the study area consist of an unconfined aquifer with a maximum thickness of 20 m and three layers of confined aquifers with thickness vary between 8 to 60 m. the hydraulic conductivity of the aquifers depends on the aquifer’s lithology range from sand, gravel, limestone, and sandstone. This hydrogeological conceptual model provides essential information for numerical groundwater models in the middle of the Randublatung groundwater basin.

scholarly journals The Significance of Groundwater Flow Modeling Study for Simulation of Opencast Mine Dewatering, Flooding, and the Environmental Impact

Water ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 848 ◽  
Author(s):  
Jacek Szczepiński
Keyword(s):  
Environmental Impact ◽  
Groundwater Flow ◽  
Mine Drainage ◽  
Numerical Models ◽  
Open Pit ◽  
Climate Conditions ◽  
Aquifer System ◽  
Flow Models ◽  
Mine Dewatering ◽  
Cyclic Changes

Simulations of open pit mines dewatering, their flooding, and environmental impact assessment are performed using groundwater flow models. They must take into consideration both regional groundwater conditions and the specificity of mine dewatering operations. This method has been used to a great extent in Polish opencast mines since the 1970s. However, the use of numerical models in mining hydrogeology has certain limitations resulting from existing uncertainties as to the assumed hydrogeological parameters and boundary conditions. They include shortcomings in the identification of hydrogeological conditions, cyclic changes of precipitation and evaporation, changes resulting from land management due to mining activity, changes in mining work schedules, and post-mining void flooding. Even though groundwater flow models used in mining hydrogeology have numerous limitations, they still provide the most comprehensive information concerning the mine dewatering and flooding processes and their influence on the environment. However, they will always require periodical verification based on new information on the actual response of the aquifer system to the mine drainage and the actual climate conditions, as well as up-to-date schedules of deposit extraction and mine closure.

scholarly journals Solutions for groundwater flow with sloping stream boundary: analytical, numerical and experimental models

2017 ◽  
Vol 49 (4) ◽  
pp. 1120-1130 ◽  
Author(s):  
Uğur Boyraz ◽  
Cevza Melek Kazezyılmaz-Alhan
Keyword(s):  
Surface Water ◽  
Groundwater Flow ◽  
Laboratory Experiments ◽  
Groundwater Resources ◽  
Experimental Models ◽  
Flow Equation ◽  
Visual Modflow ◽  
Aquifer System ◽  
Aquifer Characteristics ◽  
Made In

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.

Using groundwater levels and Specific Yield to Estimate the Recharge, South of Erbil, Kurdistan Region, Iraq

2018 ◽  
Vol 7 (4) ◽  
pp. 191
Author(s):  
Sherwan Sh. Qurtas
Keyword(s):  
Unconfined Aquifer ◽  
Middle Part ◽  
Water Levels ◽  
Specific Yield ◽  
Aquifer System ◽  
Groundwater Levels ◽  
Monitoring Wells ◽  
Water Table Fluctuation Method ◽  
Recharge Estimation ◽  
Fluctuation Method

Recharge estimation accurately is crucial to proper groundwater resource management, for the groundwater is dynamic and replenished natural resource. Usually recharge estimation depends on the; the water balance, water levels, and precipitation. This paper is studying the south-middle part of Erbil basin, with the majority of Quaternary sediments, the unconfined aquifer system is dominant, and the unsaturated zone is ranging from 15 to 50 meters, which groundwater levels response is moderate. The purpose of this study is quantification the natural recharge from precipitation. The water table fluctuation method is applied; using groundwater levels data of selected monitoring wells, neighboring meteorological station of the wells, and the specific yield of the aquifers. This method is widely used for its simplicity, scientific, realistic, and direct measurement. The accuracy depends on the how much the determination of specific yield is accurate, accuracy of the data, and the extrapolations of recession of groundwater levels curves of no rain periods. The normal annual precipitation there is 420 mm, the average recharge is 89 mm, and the average specific yield is around 0.03. The data of one water year of 2009 and 2010 has taken for some technical and accuracy reasons.

Hydrogeology and Simulation of Groundwater Flow in the Plymouth-Carver-Kingston-Duxbury Aquifer System, Southeastern Massachusetts

2009 ◽  
Author(s):  
John P. Masterson ◽  
Carl S. Carlson ◽  
Donald A. Walter ◽  
Gardner C. Other contributing authors: Bent ◽  
Andrew J. Massey
Keyword(s):  
Groundwater Flow ◽  
Aquifer System

The Distribution of Volatile Organics in a Leachate Plume, Gloucester, Ontario

1987 ◽  
Vol 22 (1) ◽  
pp. 49-64 ◽  
Author(s):  
J.F. Devlin ◽  
W.A. Gorman
Keyword(s):  
Organic Contaminants ◽  
Source Area ◽  
Unconfined Aquifer ◽  
High Concentration ◽  
Organic Contamination ◽  
Aquifer System ◽  
Aquifer Systems ◽  
Volatile Organic ◽  
Volatile Organic Contaminants ◽  
Aquifer Sediments

Abstract The Gloucester Landfill is located near Ottawa, Ontario, on a northeast trending ridge of Quaternary age. The ridge comprises outwash sediments which make up two aquifer systems. A confined system exists next to bedrock, and is overlain by a silty-clayey stratum (the confining layer) which is, in turn, overlain by an unconfined aquifer system. Two independent volatile organic plumes have previously been identified at the landfill: the southeast plume, which has penetrated the confined aquifer system, and the northeast plume which is migrating in the unconfined aquifer. The distribution of volatile organic contaminants at the northeast plume site appears to be a function of two factors: (1) heterogeneities in the aquifer sediments are causing the channeling of contaminants through a narrow path; (2) the low fraction of organic carbon in the unconfined aquifer sediments at the northeast site is resulting in little retardation of the contaminants there, relative to those at the southeast site. Acetate was the only volatile fatty acid detected in the leachate. It was measurable only in areas where the volatile organic contamination was significant. Although methane was detected in the contaminated sediments, suggesting that microbial activity was present, the high concentration of acetate (&gt;1000 ppm) which was detected down-gradient from the source area indicates that any biodegradation which is occurring is proceeding at a very slow rate.

A possible modification of groundwater flow equation using coordinate transformations

2014 ◽  
Vol 15 (2) ◽  
pp. 278-287 ◽  
Author(s):  
Abdon Atangana ◽  
Ernestine Alabaraoye
Keyword(s):  
Groundwater Flow ◽  
Prolate Spheroid ◽  
Flow Equation ◽  
Time Space ◽  
Adomian Decomposition ◽  
Iteration Methods ◽  
Groundwater Flow Equation ◽  
Factor Α ◽  
Modified Equation ◽  
Good Agreement

We described a groundwater model with prolate spheroid coordinates, and introduced a new parameter, namely τ the silhouette influence of the geometric under which the water flows. At first, we supposed that the silhouette influence approaches zero; under this assumption, the modified equation collapsed to the ordinary groundwater flow equation. We proposed an analytical solution to the standard version of groundwater as a function of time, space and uncertainty factor α. Our proposed solution was in good agreement with experimental data. We presented a good approximation to the exponential integral. We obtained an asymptotic special solution to the modified equation by means of the Adomian decomposition and variational iteration methods.

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