E3S Web Conf.
Volume 54, 201825th Salt Water Intrusion Meeting (SWIM 2018)
|Number of page(s)||6|
|Published online||17 September 2018|
Laboratory Scale Investigation of Dispersion Effects on Saltwater Movement due to Cutoff Wall Installation
Nippon Koei Co. Ltd., Tokyo, Japan
2 Kagoshima University, Kagoshima, Japan
3 University of the Philippines Los Baños, Laguna, Philippines
Contact Information: Roger A. Luyun Jr., Land and Water Resources Division, College of Engineering and Agro-industrial Technology, University of the Philippines Los Baños, Phone/Fax: +6349-536-2387, Email: firstname.lastname@example.org
In the numerical investigation of saltwater transport in coastal aquifers, we need to correctly evaluate the hydrodynamic dispersion in the flow field. In this study, we focused on the role of dispersivity in the removal process of residual saltwater in a laboratory scale cutoff wall experiment. From a pulse-type fluorescent tracer injection experiment in a saturated porous media of glass beads with a mean diameter of 0.088 cm, the estimated longitudinal and transverse dispersivities were found to be 0.07 cm and 0.0025 cm, respectively. Numerical analysis of the saltwater intrusion and subsequent removal after cutoff wall installation using SEAWAT and the generated dispersivity ratio (αL/αT) of 28 reproduces well the measured salt concentration changes with time. Whereas, if a dispersivity ratio of 10 is used in the numerical simulation, transverse dispersion in the saltwater and freshwater mixing zone becomes large and the residual saltwater is removed faster than the laboratory experiment. Inversely, if 100 was used, the residual saltwater removal time took longer. The transverse dispersion is a key parameter in the mechanical dispersion of saltwater in the mixing zone after cutoff wall installation.
© The Authors, published by EDP Sciences, 2018
This is an Open Access article distributed under the terms of the Creative Commons Attribution License 4.0 (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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