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Effect of sand lenses on groundwater flow and contaminant migration
Author(s) -
San K. W. Edward,
Rowe R. Kerry
Publication year - 1993
Publication title -
international journal for numerical and analytical methods in geomechanics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.419
H-Index - 91
eISSN - 1096-9853
pISSN - 0363-9061
DOI - 10.1002/nag.1610170402
Subject(s) - hydraulic conductivity , aquifer , groundwater flow , groundwater , geotechnical engineering , lens (geology) , flow (mathematics) , geology , finite element method , homogeneous , mechanics , soil science , soil water , engineering , petroleum engineering , structural engineering , mathematics , physics , combinatorics
The effect of homogeneous sand lenses on the groundwater flow in an otherwise homogeneous clayey deposit is examined by performing Monte Carlo simulations using a finite element flow model. In the simulations, the locations of the sand lenses are assumed to be mutually independent. The paper examines the effect on the flow field in a clayey deposit of (a) different percentages of sand lenses, (b) different hydraulic conductivities of the sand lenses, (c) different average sand lens sizes, (d) non‐uniformity of the sizes of the sand lenses, and (e) localization of the sand lenses. The effect of these non‐uniform flow fields on contaminant migration is then examined using a finite element contaminant transport model. For the range of cases considered it is shown that: the volume of sand lenses present has a greater influence than the shape, size, location and hydraulic conductivity of the sand lenses; simplified calculations performed using the geometric and harmonic means of hydraulic conductivity bracket the behaviour evident from more complex analyses; and the maximum impact on an aquifer separated from a waste disposal facility by a deposit containing sand lenses can be modelled to sufficient accuracy, using quite simple flow and contaminant transport models.