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

Open-File Report 94-343
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Abstract

Proper discretization of a ground-water-flow field is necessary for the accurate simulation of ground-water flow by models. Although discretiza- tion guidelines are available to ensure numerical stability, current guidelines arc flexible enough (particularly in vertical discretization) to allow for some ambiguity of model results. Testing of two common types of vertical-discretization schemes (horizontal and nonhorizontal-model-layer approach) were done to simulate sloping hydrogeologic units characteristic of New England. Differences of results of model simulations using these two approaches are small. Numerical errors associated with use of nonhorizontal model layers are small (4 percent). even though this discretization technique does not adhere to the strict formulation of the finite-difference method. It was concluded that vertical discretization by means of the nonhorizontal layer approach has advantages in representing the hydrogeologic units tested and in simplicity of model-data input. In addition, vertical distortion of model cells by this approach may improve the representation of shallow flow processes.
Publication type Report
Publication Subtype USGS Numbered Series
Title Comparison of vertical discretization techniques in finite-difference models of ground-water flow; example from a hypothetical New England setting
Series title Open-File Report
Series number 94-343
DOI 10.3133/ofr94343
Edition -
Year Published 1994
Language ENGLISH
Publisher U.S. Geological Survey ; USGS Earth Science Information Center, Open-File Reports Section [distributor],
Description iv, 25 p. :ill. ;28 cm.
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