Evaluating the hydraulic effects of changes in aquifer elevation using curvilinear coordinates

Weiss, Emanuel

doi:10.1016/0022-1694(85)90034-4

Cited by 8 publications

(6 citation statements)

References 9 publications

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“…A maximum difference of about 4 percent occurs at the lower parts of the hillside between the nonhorizontal model and the 54-layer horizontal model. This discrepancy is 1.4 percent higher than that reported by Weiss (1985) for a comparable sloping system.…”

Section: Comparison Of Horizontal-model-layer and Nonhorizontal-modelcontrasting

confidence: 59%

“…To correct for this misalignment, it is necessary to include the cross products of the hydraulic-conductivity tensor that account for the angle of deviation ( fig. 2) (Weiss, 1985).…”

Section: Considerations In Vertical Discretization Of Finite-differenmentioning

confidence: 99%

“…A profile of heads is shown for the lowermost model layer where the maximum contrast in model heads occur; the maximum head contrast occurs at the base or lower boundary because it is furthest from the upper boundary where heads are controlled. Weiss (1985) in his evaluation of simulating horizontal and nonhorizontal geologic units chose an area of the model closest to a specified-head boundary to compare differences in model heads. As a result, differences in model performance probably are underestimated.…”

Section: Comparison Of Horizontal-model-layer and Nonhorizontal-modelmentioning

confidence: 99%

“…Although it has been acknowledged that with the nonhorizontal-layer approach some numerical accuracy is sacrificed to produce an improved conceptual representation of the physical system (McDonald and Harbaugh, 1988), little experimentation has been done to assess the ramifications of these discretization practices on error in model results. Weiss (1985) did a numerical study examining the differences of ground-water flow between horizontal stratigraphic units and synclinal stratigraphic units. In it he used variations in discretization of the horizontal-model-layer approach to test the formulation of flow equations from a curvilinear grid system earlier described by Aziz and Settari (1979).…”

Section: Introductionmentioning

confidence: 99%

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Comparison of vertical discretization techniques in finite-difference models of ground-water flow; example from a hypothetical New England setting

Harte¹

1994

Open-File Report

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Section: Comparison Of Horizontal-model-layer and Nonhorizontal-modelcontrasting

confidence: 59%

“…To correct for this misalignment, it is necessary to include the cross products of the hydraulic-conductivity tensor that account for the angle of deviation ( fig. 2) (Weiss, 1985).…”

Section: Considerations In Vertical Discretization Of Finite-differenmentioning

confidence: 99%

Section: Comparison Of Horizontal-model-layer and Nonhorizontal-modelmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Comparison of vertical discretization techniques in finite-difference models of ground-water flow; example from a hypothetical New England setting

Harte¹

1994

Open-File Report

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“…This is different from the truncation error associated with grid size and contains a component proportional to the deviation of the grid from being orthogonal. The errors induced by conforming grids were previously studied by Weiss (1985), Harte (1994), Hoagland and Pollard (2003), and Bower et al (2004). They concluded that the appropriate grid size could be determined a priori for a given problem.…”

Section: Introductionmentioning

confidence: 98%

An Investigation of Numerical Grid Effects in Parameter Estimation

Zyvoloski

Vesselinov

2006

Groundwater

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Modern ground water characterization and remediation projects routinely require calibration and inverse analysis of large three-dimensional numerical models of complex hydrogeological systems. Hydrogeologic complexity can be prompted by various aquifer characteristics including complicated spatial hydrostratigraphy and aquifer recharge from infiltration through an unsaturated zone. To keep the numerical models computationally efficient, compromises are frequently made in the model development, particularly, about resolution of the computational grid and numerical representation of the governing flow equation. The compromise is required so that the model can be used in calibration, parameter estimation, performance assessment, and analysis of sensitivity and uncertainty in model predictions. However, grid properties and resolution as well as applied computational schemes can have large effects on forward-model predictions and on inverse parameter estimates. We investigate these effects for a series of one- and two-dimensional synthetic cases representing saturated and variably saturated flow problems. We show that "conformable" grids, despite neglecting terms in the numerical formulation, can lead to accurate solutions of problems with complex hydrostratigraphy. Our analysis also demonstrates that, despite slower computer run times and higher memory requirements for a given problem size, the control volume finite-element method showed an advantage over finite-difference techniques in accuracy of parameter estimation for a given grid resolution for most of the test problems.

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Comparison of alternative representations of hydraulic-conductivity anisotropy in folded fractured-sedimentary rock: modeling groundwater flow in the Shenandoah Valley (USA)

2009

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Evaluating the hydraulic effects of changes in aquifer elevation using curvilinear coordinates

Cited by 8 publications

References 9 publications

Comparison of vertical discretization techniques in finite-difference models of ground-water flow; example from a hypothetical New England setting

Comparison of vertical discretization techniques in finite-difference models of ground-water flow; example from a hypothetical New England setting

An Investigation of Numerical Grid Effects in Parameter Estimation

Comparison of alternative representations of hydraulic-conductivity anisotropy in folded fractured-sedimentary rock: modeling groundwater flow in the Shenandoah Valley (USA)

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