Session Start Date

6-1-1988

Abstract

Traditionally clay soils have been regarded as being relatively impermeable to the migration of water and contaminants. Recent studies in Louisiana are beginning to show, however, that laboratory permeability tests are not true indicators of the ability of an in-situ soil to retain or transmit fluids. Both the depositional and post-depositional environment of a soil can greatly alter its in-situ permeability. In particular, post-depositional structural fractures provide preferential pathways for contaminant migration at rates that far exceed those predicted by using laboratory permeability values. Difficulties in field identification of these pathways reduces modeling of their effect on site hydrology to very basic terms. Since their distribution is not yet predictable, the net increase in permeability caused by their presence at a site cannot be factored into any hydrologic models, except as gross estimates.

Department(s)

Civil, Architectural and Environmental Engineering

Appears In

International Conference on Case Histories in Geotechnical Engineering

Meeting Name

Second Conference

Publisher

University of Missouri--Rolla

Publication Date

6-1-1988

Document Version

Final Version

Rights

© 1988 University of Missouri--Rolla, All rights reserved.

Document Type

Article - Conference proceedings

File Type

text

Language

English

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A Study of Contamination Migration at a Hazardous Waste Facility in Louisiana

Traditionally clay soils have been regarded as being relatively impermeable to the migration of water and contaminants. Recent studies in Louisiana are beginning to show, however, that laboratory permeability tests are not true indicators of the ability of an in-situ soil to retain or transmit fluids. Both the depositional and post-depositional environment of a soil can greatly alter its in-situ permeability. In particular, post-depositional structural fractures provide preferential pathways for contaminant migration at rates that far exceed those predicted by using laboratory permeability values. Difficulties in field identification of these pathways reduces modeling of their effect on site hydrology to very basic terms. Since their distribution is not yet predictable, the net increase in permeability caused by their presence at a site cannot be factored into any hydrologic models, except as gross estimates.