Sharp Interface Approach for Regional and Well Scale Modeling of Small Island Freshwater Lens: Tongatapu Island
1
Department of Civil Engineering, Dong-A University, Busan 49315, Korea
2
Integrative Climate Research Team, APEC Climate Center, Busan 48058, Korea
3
Ministry of Lands & Natural Resources, Nuku’alofa, Tonga
*
Author to whom correspondence should be addressed.
Water 2018, 10(11), 1636; https://doi.org/10.3390/w10111636
Received: 28 September 2018 / Revised: 8 November 2018 / Accepted: 9 November 2018 / Published: 12 November 2018
(This article belongs to the Special Issue Groundwater Resources and Salt Water Intrusion in a Changing Environment)
Sustainable management of small island freshwater resources requires an understanding of the extent of freshwater lens and local effects of pumping. In this study, a methodology based on a sharp interface approach is developed for regional and well scale modeling of island freshwater lens. A quasi-three-dimensional finite element model is calibrated with freshwater thickness where the interface is matched to the lower limit of the freshwater lens. Tongatapu Island serves as a case study where saltwater intrusion and well salinization for the current state and six long-term stress scenarios of reduced recharge and increased groundwater pumping are predicted. Though no wells are salinized currently, more than 50% of public wells are salinized for 40% decreased recharge or increased groundwater pumping at 8% of average annual recharge. Risk of salinization for each well depends on the distance from the center of the well field and distance from the lagoon. Saltwater intrusions could occur at less than 50% of the previous estimates of sustainable groundwater pumping where local pumping was not considered. This study demonstrates the application of a sharp interface groundwater model for real-world small islands when dispersion models are challenging to be implemented due to insufficient data or computational resources.
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Keywords:
sharp interface numerical modeling; freshwater lens; saltwater intrusion; well salinization; small islands; Tongatapu
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MDPI and ACS Style
Babu, R.; Park, N.; Yoon, S.; Kula, T. Sharp Interface Approach for Regional and Well Scale Modeling of Small Island Freshwater Lens: Tongatapu Island. Water 2018, 10, 1636. https://doi.org/10.3390/w10111636
AMA Style
Babu R, Park N, Yoon S, Kula T. Sharp Interface Approach for Regional and Well Scale Modeling of Small Island Freshwater Lens: Tongatapu Island. Water. 2018; 10(11):1636. https://doi.org/10.3390/w10111636
Chicago/Turabian StyleBabu, Roshina; Park, Namsik; Yoon, Sunkwon; Kula, Taaniela. 2018. "Sharp Interface Approach for Regional and Well Scale Modeling of Small Island Freshwater Lens: Tongatapu Island" Water 10, no. 11: 1636. https://doi.org/10.3390/w10111636
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