Groundwater movement in a glacial complex, Cochrane district, Ontario

1970 ◽  
Vol 7 (3) ◽  
pp. 869-883 ◽  
Author(s):  
Myles L. Parsons
Keyword(s):  
Groundwater Flow ◽  
Northern Ontario ◽  
Local Flow ◽  
Groundwater Movement ◽  
Crystalline Bedrock ◽  
Regional Flow ◽  
Groundwater Environment ◽  
Flow Systems ◽  
Lateral Extent ◽  
Sand And Gravel

Groundwater flow is examined in a glacial geologic environment thought to be typical of the Clay Belt of northern Ontario. The geologic framework comprises two eskerine sand bodies separated and partially covered by an extensive plain of lacustrine clay, all underlain by discontinuous till resting on fractured crystalline bedrock. The groundwater flow medium is characterized by large hydraulic conductivity variations ranging over at least four orders of magnitude. Consequently, two distinctive types of groundwater environment are recognized: the esker environments consisting of elongated linear bodies of very permeable sand and gravel, and the clay plain environment characterized by a clay-over-till layered medium of relatively low permeability.Piezometric head measurements are interpreted with the aid of a numerical model of the potential field, obtained as a solution to the differential equation of steady-state groundwater flow. Three types of groundwater flow systems are distinguished: local flow systems associated with the topographically high eskers, local flow systems of limited lateral extent centered around the entrenched valleys in the clay plain, and regional flow systems with recharge in the flat interstream clay plain areas extending into the bedrock.

The evolution and non-fickian flow of local stagnant zones in hierarchically nested groundwater flow system under different rainfall infiltration intensity

2021 ◽  
Author(s):  
Ronglin Sun ◽  
Liqun Jiang ◽  
Xing Liang ◽  
Menggui Jin
Keyword(s):  
Climate Change ◽  
Groundwater Flow ◽  
Flow System ◽  
Rainfall Infiltration ◽  
Stagnant Zone ◽  
Local Flow ◽  
Discharge Area ◽  
Directional Flow ◽  
Regional Flow ◽  
Flow Systems

<p>Groundwater plays an active role in certain geologic processes that has been recognized in numerous subdisciplines for a long time. According to Toth (1963, 2009), gravity-driven regional groundwater flow is induced by elevation differences in the water table and its pattern is self-organized into hierarchical sets of local, intermediate and regional flow systems.  Convergence of two flow systems results in a stagnant zone called hydraulic trap which is under the discharge area, and diverge of two flow systems results in a stagnant zone called quasi-stagnant zone which is under the water divide. These stagnant zones have been found to be critical to accumulation of transported mineral matter. Based on analytical and numerical solutions, some researchers reported that the local stagnant point or zone that are located under the local counter directional flow system. There is a question that whether hydraulic trap and quasi-stagnant zone is separate or integrate, and whether they are located under the discharge area or water divide or counter directional flow systems.</p><p>In this study, two-dimensional numerical cross-sectional model is used to investigate the effect of climate change on local stagnant zones and whether the hydraulic trap and quasi-stagnant zone is separate or integrate. Considering the climate change of basin and the change of rainfall infiltration intensity, a flux upper boundary is used to simulate the rainfall recharge. Then a synthetic homogeneous sandbox with three potential sinks is used to validate the evolution of the hierarchical nested groundwater flow systems considering different rainfall infiltration intensity. Salt tracer test is used to investigate the effect of stagnant zones on solute transport.</p><p>According to numerical results, we concluded that the hydraulic traps and quasi-stagnant are possible to be separate only for simple local systems and the two local stagnant zones are located on two sides of the counter directional flow system. When nested flow systems occur, such as local-intermediate, local-intermediate-local, local-regional, the local hydraulic traps and quasi-stagnant zones are always integrated under the local counter directional flow systems. Laboratory results show that when the rainfall infiltration intensity reduce, the groundwater flow pattern will change and the penetration depth and scope of counter directional local flow system will decrease. The corresponding local stagnant zone will slowly be closing to the discharge area of that counter directional local flow system. Salt tracer tests show that there are obvious non-fickian phenomenon in the local stagnant zones in hierarchically nested flow systems even in the homogeneous aquifer.</p>

Relation between electric analogue patterns of groundwater flow and accumulation of hydrocarbons

1970 ◽  
Vol 7 (3) ◽  
pp. 988-1007 ◽  
Author(s):  
J. Tóth
Keyword(s):  
Groundwater Flow ◽  
Flow Paths ◽  
Groundwater Movement ◽  
Regional Systems ◽  
Regional Flow ◽  
Hydraulic Conditions ◽  
Flow Systems ◽  
Hydrocarbon Fields ◽  
System 2 ◽  
Effective Segregation

The types of features of electric analogue patterns of groundwater movement found most frequently associated with hydrocarbon accumulation are: regional systems, ascending limbs, and stagnant zones. The reason for the preferential accumulation of hydrocarbons under these hydraulic conditions appears to be an increase in the effectiveness of the structural and lithologic traps. This may be explained by: 1) the large quantities of hydrocarbons transported by the regional flow systems; 2) effective segregation of hydrocarbons from the transporting water owing to a divergence between the flow directions of the migrating fluids; 3) effective mechanical (capillary) filtration by the large number of permeability changes along ascending, hence cross-formational flow paths; 4) effective segregation of gases from the water due to a rapid decrease in pressure along ascending flow paths; 5) slight inclination of oil- or gas–water interfaces causing even minor structures to become relatively effective traps.Examples of theoretical subsurface hydrodynamics as well as of practical observations of hydrocarbon occurrences found in literature implicitly or explicitly corroborate these findings. 1) According to Kortsenshteyn 1964, the amounts of economic hydrocarbon reserves are directly proportional to the volume of the transporting flow system; 2) the consistent association of hydrocarbon accumulations with artesian basins often reported by Soviet petroleum geologists and hydrogeologists clearly indicates conditions favorable for hydrocarbon associations in regions of ascending groundwater flow; 3) by application of Hubbert's equation given for the tilt of the oil– or gas–water interface a theoretical ratio of 8.4:1 is expected for preferential association of hydrocarbons with zones of stagnant and ascending groundwater as compared with the lateral limbs of flow systems along the Etzikom Coulee cross section, and by analysis of the analogue flow-pattern an empirical ratio of 6.8:1 is found, representing a good agreement between anticipation and facts; 4) in the Volga–Ural petroleum province a definite decrease in number and importance of major hydrocarbon fields with decreasing depth is reported, suggesting an effective filtration as a consequence of the ascending movement of groundwater.Thus the theoretical considerations, experimental results, and practical observations all indicate that certain hydrocarbon accumulations are identifiably related to the presently prevailing pattern of groundwater flow. This, in turn, can be realistically approximated from the configuration of the water table and consists of topographically controlled, hydraulically continuous, and regionally unconfined flow systems, modified in detail by the local heterogeneities of the geologic framework.

scholarly journals The Control of Groundwater Flow Systems and Geochemical Processes on Groundwater Chemistry: A Case Study in Wushenzhao Basin, NW China

Water ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 790 ◽  
Author(s):  
Min Lyu ◽  
Zhonghe Pang ◽  
Lihe Yin ◽  
Jun Zhang ◽  
Tianming Huang ◽  
...  
Keyword(s):  
Groundwater Flow ◽  
Flow System ◽  
Groundwater Resources ◽  
Chemical Compositions ◽  
Nw China ◽  
Water Types ◽  
Groundwater Flow Systems ◽  
Regional Flow ◽  
Flow Systems

The lowest reaches of a large-scale basin could be the discharge areas of local, intermediate and regional groundwater flow systems with significantly distinct travel distances and travel times. This study aims to delineate the groundwater chemical characteristics and the mechanism controlling the chemical evolution in the lowest reaches of the Wushenzhao Cretaceous basin, NW China. A total of 38 groundwater samples were collected and were chemically classified into five distinct water types by means of a Piper Plot. According to the hydrogeological setting and groundwater age, the spatial distribution of these water types is found to be associated with hierarchically nested groundwater flow systems (local and regional system): Types 1, 2, 3 and 4 belong to the local groundwater flow system, while type 5 belongs to the regional flow system. Graphical plots, stable isotopes and geochemical modeling techniques were used to interpret the observed compositions. The results show the dominance of carbonate and gypsum dissolution in type 1 waters; ion exchange in types 2, 3 and 4; and evaporite dissolution in type 5. In addition, human activities in the form of extensive irrigation also affect the chemical compositions of type 1 water. These findings are important for the sustainable management of groundwater resources in the study area.

Groundwater flow systems in the crystalline rocks of the Okanagan Highland, British Columbia

1968 ◽  
Vol 5 (4) ◽  
pp. 813-824 ◽  
Author(s):  
D. W. Lawson
Keyword(s):  
Hydraulic Conductivity ◽  
Groundwater Flow ◽  
Flow System ◽  
Crystalline Rock ◽  
Crystalline Rocks ◽  
Two Dimensional ◽  
Local Flow ◽  
Groundwater Flow Systems ◽  
Flow Systems ◽  
Two Dimensional Flow

An investigation of the groundwater flow systems associated with the most prominent topographic expression in the Okanagan Highland (a U-shaped valley) revealed that the hydraulic conductivity of the crystalline rock varies exponentially with depth, and that the local flow systems within the upper 125 to 150 ft of the crystalline rock conduct an estimated 10 to 17 Imperial gallons per day per foot thickness in a two-dimensional flow system. These local flow systems are quantitatively the most significant in the Okanagan Highland.

scholarly journals Methane in groundwater before, during, and after hydraulic fracturing of the Marcellus Shale

2018 ◽  
Vol 115 (27) ◽  
pp. 6970-6975 ◽  
Author(s):  
E. Barth-Naftilan ◽  
J. Sohng ◽  
J. E. Saiers
Keyword(s):  
Groundwater Quality ◽  
Shale Gas ◽  
Marcellus Shale ◽  
Gas Wells ◽  
Local Flow ◽  
Gas Well ◽  
Monitoring Wells ◽  
Regional Flow ◽  
Flow Systems ◽  
Methane Concentrations

Concern persists over the potential for unconventional oil and gas development to contaminate groundwater with methane and other chemicals. These concerns motivated our 2-year prospective study of groundwater quality within the Marcellus Shale. We installed eight multilevel monitoring wells within bedrock aquifers of a 25-km2 area targeted for shale gas development (SGD). Twenty-four isolated intervals within these wells were sampled monthly over 2 years and groundwater pressures were recorded before, during, and after seven shale gas wells were drilled, hydraulically fractured, and placed into production. Perturbations in groundwater pressures were detected at hilltop monitoring wells during drilling of nearby gas wells and during a gas well casing breach. In both instances, pressure changes were ephemeral (<24 hours) and no lasting impact on groundwater quality was observed. Overall, methane concentrations ([CH4]) ranged from detection limit to 70 mg/L, increased with aquifer depth, and, at several sites, exhibited considerable temporal variability. Methane concentrations in valley monitoring wells located above gas well laterals increased in conjunction with SGD, but CH4 isotopic composition and hydrocarbon composition (CH4/C2H6) are inconsistent with Marcellus origins for this gas. Further, salinity increased concurrently with [CH4], which rules out contamination by gas phase migration of fugitive methane from structurally compromised gas wells. Collectively, our observations suggest that SGD was an unlikely source of methane in our valley wells, and that naturally occurring methane in valley settings, where regional flow systems interact with local flow systems, is more variable in concentration and composition both temporally and spatially than previously understood.

Groundwater flow pattern and age distribution under transient conditions

2021 ◽  
Author(s):  
Menggui Jin ◽  
Yan Li ◽  
Jiale Wang ◽  
Xing Liang
Keyword(s):  
Probability Density Function ◽  
Groundwater Flow ◽  
Probability Density ◽  
Stagnation Point ◽  
Residence Time ◽  
Flow System ◽  
Local Flow ◽  
Groundwater Flow System ◽  
Flow Systems ◽  
Upper Boundary

&lt;p&gt;The distribution of groundwater ages under transient conditions are investigated by a numerical model coupled groundwater flow and age, and the nested pattern of groundwater flow are determined by the probability density function of residence time. The variation of local groundwater flow system to the fluctuation of upper boundary head evolves rapidly. During the process from the initial steady to the unsteady state, the groundwater age field evolves with simulation time and gradually reaches a new dynamic equilibrium after about 50 years. The age abrupt interface between the local and intermediate flow systems gradually shifts upward, and the scale of the local flow system gradually decreases. The groundwater ages of the regional and intermediate flow systems are mainly controlled by the long-term dynamic component of the upper boundary head, while the local flow systems are mainly influenced by the transient periodic fluctuation. The location of the stagnation points are mainly controlled by the upper boundary head. The larger head difference between recharge and discharge area is, the greater penetrated depth of the stagnation point is. The location of the stagnation point indicates the penetrated depth of the local flow system. The larger head fluctuates, the deeper stagnation point is, leading to a greater penetration depth of the local flow system. Molecular dispersion causes the scatters of residence time probability density function to aggregate near the inflection point, and the aggregation area mainly locates at the junction of basin-scale flow systems. The transition of groundwater flow field will intensify the mixing of old and new water, leading to the blurring or even disappearance of the residence time abrupt interface. The dispersion of groundwater mixing is poor in steady state, and the convective-dispersive effect gradually increases with time in unsteady state. Traditional hydraulics methods based on flow nets and stagnation points can effectively identify the groundwater flow system, but the differences in groundwater chemical characteristics and ages at long-term scales cannot be clearly described by these methods, as well as the evolution of groundwater flow system at long time scale. The groundwater residence time distribution expressed by the probability density function, which comprehensively involves the spatial and temporal information of groundwater interaction, can help accurately distinguish different groundwater flow systems at long time scales. The methods proposed in this study will act as a meaningful guidance for the delineation of groundwater flow system in the real world.&lt;/p&gt;

Abnormal groundwater flow system between two rivers: a numerical investigation

2020 ◽  
Author(s):  
Li Ruoyi ◽  
Wang Xu-Sheng ◽  
Han Peng-Fei
Keyword(s):  
Groundwater Flow ◽  
Water Level ◽  
Flow System ◽  
Groundwater Discharge ◽  
Local Flow ◽  
Groundwater Flow System ◽  
Through Flow ◽  
Flow Systems ◽  
Pass Through ◽  
Infiltration Recharge

&lt;p&gt;Groundwater flow system has long been recognized as the local, intermediate and regional flow systems since Toth (1963). For groundwater flow in an unconfined aquifer between two parallel rivers (or ditches), as indicated by Hubbert (1940), there are two local flow systems contributing groundwater discharge to the two rivers from infiltration recharge. Surprisingly, this model has never been examined until Han et al. (2019) pointed out that something may be wrong: not only two flow systems exist. The problem was further investigated with a two-dimensional numerical model on MODFLOW for saturated groundwater flow below the arch-shape water table receiving a uniform infiltration recharge. Streamlines were obtained with MODPATH to identify the flow systems. We discovered that an abnormal groundwater flow system could emerge beneath the two local flow systems under some conditions, which forms a pass through flow from the high river to the low river. This pass-through flow system exists when the water level difference between the two rivers is sufficiently large and the infiltration recharge is sufficiently low. As a result, the base flow of the low river may be not only attributed to the captured infiltration recharge from the nearby local flow system but also partly originated from the high river. The ratio of the contribution from the pass-through flow system to the total groundwater discharge toward the low river could be higher than 20% and almost linearly increases with the water level difference between two rivers. More details of such an abnormal groundwater flow system were investigated as well. &amp;#160;&lt;/p&gt;

scholarly journals Modeling Groundwater Flow System of a Drainage Basin in the Basement Complex Environment of Southwestern Nigera

2018 ◽  
Vol 1 ◽  
pp. 1-7
Author(s):  
Akinola S. Akinwumiju ◽  
Martins O. Olorunfemi
Keyword(s):  
Groundwater Flow ◽  
Drainage Basin ◽  
Flow System ◽  
Subsurface Water ◽  
Complex Environment ◽  
Basement Complex ◽  
Local Flow ◽  
Groundwater Flow System ◽  
Regional Flow ◽  
Flow Directions

This study attempted to model the groundwater flow system of a drainage basin within the Basement Complex environment of Southwestern Nigeria. Four groundwater models were derived from Vertical Electrical Sounding (VES) Data, remotely sensed data, geological information (hydrolineaments and lithology) and borehole data. Subsequently, two sub-surface (local and regional) flow systems were delineated in the study area. While the local flow system is controlled by surface topography, the regional flow system is controlled by the networks of intermediate and deep seated faults/fractures. The local flow system is characterized by convergence, divergence, inflow and outflow in places, while the regional flow system is dominated by NNE-SSW and W-E flow directions. Minor flow directions include NNW-SSE and E-W with possible linkages to the main flow-paths. The NNE-SSW regional flow system is a double open ended flow system with possible linkage to the Niger Trough. The W-E regional flow system is a single open ended system that originates within the study area (with possible linkage to the NNE-SSW regional flow system) and extends to Ikogosi in the adjoining drainage basin. Thus, the groundwater drainage basin of the study area is much larger and extensive than its surface drainage basin. The all year round flowing (perennial) rivers are linked to groundwater outcrops from faults/fractures and contact zones. Consequently, larger percentage of annual rainwater usually leaves the basin in form of runoff and base flow. Therefore, the basin is categorized as a donor basin but with suspected subsurface water input at its northeastern axis.

Gangue Yards Vegetation Restoration and Groundwater Pollution Control in Arid Zone — A Field Application

2012 ◽  
Vol 518-523 ◽  
pp. 2535-2538 ◽  
Author(s):  
Shao Gang Dong ◽  
Bai Wei Liu ◽  
Zhi Bin Jia ◽  
Zhi Yi Wang
Keyword(s):  
Groundwater Flow ◽  
Groundwater Pollution ◽  
Arid Zone ◽  
Vegetation Restoration ◽  
Permeable Reactive Barrier ◽  
Hazardous Substances ◽  
Coal Waste ◽  
Groundwater Flow Systems ◽  
Groundwater Environment ◽  
Flow Systems

Based on the eco-hydrogeological survey, sampling analysis and combined with groundwater flow systems theory, studied a gully gangue yards of Daliuta mine area on groundwater environmental effect. The results showed that pile of coal waste change the original characteristics of groundwater flow systems, the bottom of gangue heap long term immersion in groundwater, the toxic and hazardous substances unleashing, and with the groundwater runoff to the downstream spread. Combined with the eco-hydrogeology and hydrogeochemistry method, using the Loess carry out the gangue vegetation restoration and groundwater pollution remediation: by cover about 0.3m thickness loess at the top of the gangue yards, and planting Alfalfa, Artemisia ordosica, in order to restoration vegetation of the upper part of sites; In the downstream of gangue yards construct the loess permeable reactive barrier, using the loess adsorb the pollutants in the gangue leachate and purify the groundwater. Through the treatment approaches, gangue yards ecological and groundwater environment has been greatly improved.

scholarly journals Influences of hydraulic boundary conditions on the deep fluid flow in a 3D regional model (central Upper Rhine Graben)

2022 ◽  
Vol 81 (1) ◽  
Author(s):  
Nora Koltzer ◽  
Giulia Kommana ◽  
Mauro Cacace ◽  
Maximilian Frick ◽  
Judith Bott ◽  
...  
Keyword(s):  
Fluid Flow ◽  
Boundary Conditions ◽  
Groundwater Flow ◽  
Flow Dynamics ◽  
Upper Rhine Graben ◽  
Local Flow ◽  
Regional Flow ◽  
Rhine Graben ◽  
Deep Fluid ◽  
Upper Rhine

AbstractKnowledge of groundwater flow is of high relevance for groundwater management or the planning of different subsurface utilizations such as deep geothermal facilities. While numerical models can help to understand the hydrodynamics of the targeted reservoir, their predictive capabilities are limited by the assumptions made in their setup. Among others, the choice of appropriate hydraulic boundary conditions, adopted to represent the regional to local flow dynamics in the simulation run, is of crucial importance for the final modelling result. In this work, we systematically address this problematic in the area of the central part of the Upper Rhine Graben. We quantify how and to which degree different upper boundary conditions and vertical cross-boundary fluid movement influence the calculated deep fluid flow conditions in the area under study. Robust results, which are insensitive to the choice of boundary condition, are: (i) a regional groundwater flow component descending from the graben shoulders to rise at its centre and (ii) the presence of heterogeneous hydraulic potentials at the rift shoulders. Contrarily, results affected by the chosen boundary conditions are: (i) calculated flow velocities, (ii) the absolute position of the upflow axis, and (iii) the evolving local flow dynamics. If, in general, the investigated area is part of a supra-regional flow system—like the central Upper Rhine Graben is part of the entire Upper Rhine Graben—the inflow and outflow across vertical model boundaries need to be considered.

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