Saltwater dynamics due to cut-off wall installation in coastal unconfined aquifers: Experimental and numerical studies

Issue Date

1-2008

Abstract

In the construction of subsurface dams in coastal aquifers, investigations of the movement and removal of residual saltwater in the storage area are not usually carried out because of difficulties in monitoring. Experimental and numerical studies were thus performed to understand the saltwater dynamics due to the installation of cut-off walls. Experimental results for cut-off walls with opening on the upper part of the aquifer showed the initial advance, gradual retreat and attenuation, and complete removal of the residual saltwater. A shorter cut-off wall exhibited faster attenuation of residual saltwater than a higher cutoff wall. Numerical simulation using SEAWAT verified the experimental results. Flow patterns showed dispersed saltwater was carried by the freshwater discharge along the mixing zone and over the cut-off wall forming a circulation flow in the residual saltwater region, and eventually all the remaining saltwater in the storage area was flushed out. Numerical results also revealed a minimum cut-off wall height limit to achieve complete removal of the residual saltwater. For cut-off walls with opening on the lower part of the aquifer, experimental results showed that more effective attenuation of the saltwater wedge occurred with deeper cutoff wall penetration, which is in general agreement with numerical results. Copyright © 2008 IAHS Press.

Source or Periodical Title

IAHS-AISH Publication

ISSN

1447815

Page

214-219

Document Type

Article

Language

English

Subject

Coastal aquifer, Cut-off wall, Saltwater intrusion, SEAWAT, Subsurface dam

Digital Copy

None

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