Management of saltwater intrusion using 3D numerical modelling: a frst for Pacifc Island country of Vanuatu

Sharan, Ashneel and Datta, Bithin and Lal, Alvin and Kotra, Krishna K. (2024) Management of saltwater intrusion using 3D numerical modelling: a frst for Pacifc Island country of Vanuatu. Environmental Monitoring and Assessment, 196 (120). NA. ISSN 0167-6369

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Abstract

Small island countries like Vanuatu are facing the brunt of climate change, sea level rise (SLR), tropical cyclones, and limited or declining access to freshwater. The Tagabe coastal aquifer in Port Vila (the capital of Vanuatu) shows the presence of salinity, indicating saltwater intrusion (SWI). This study aims to develop and evaluate effective
SWI management strategies for Tagabe coastal aquifer. To manage SWI, the numerical simulation model for the study area was developed using the SEAWAT code. The flow model was developed using MODFLOW and the transport model was developed using MT3DMS. Whereby SEAWAT solved flow and transport equations simultaneously. The model was calibrated, and different scenarios were evaluated for the management of SWI. The SLR was also considered in the model simulations. The results indicated that increased population, pumping rates, and SLR affect the SWI rates. To manage the SWI, we introduced hydraulic barriers like barrier wells and injection wells which effectively managed SWI in Tagabe coastal aquifer. The results from this study are significantly important whereby, the water managers, site owners, and governing bodies can use the management strategies presented in this study to create policies and regulations for managing SWI rates in Port Vila. Additionally, the water industry, private businesses, and investors who wish to extract groundwater from the Tagabe can use this study as a reference for daily or yearly freshwater production rates without the risk of SWI.

Item Type:	Journal Article
Uncontrolled Keywords:	Groundwater modelling · Saltwater intrusion · SEAWAT · Coastal aquifer · Hydraulic barriers
Subjects:	Q Science > Q Science (General) Q Science > QE Geology T Technology > TD Environmental technology. Sanitary engineering
Divisions:	School of Agriculture, Geography, Environment, Ocean and Natural Sciences (SAGEONS)
Depositing User:	Krishna Kotra
Date Deposited:	28 Jan 2024 23:26
Last Modified:	28 Jan 2024 23:26
URI:	https://repository.usp.ac.fj/id/eprint/14378

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