Seawater Intrusion Assessment based on Geological, Hydrogeological, Cl/Br vs Cl Graphical Analysis, Recharge Area, and Groundwater Usage in Makassar Coastal Area, South Sulawesi, Indonesia

Sunu Ardhi Nugroho(1*), Wahyu Wilopo(2), Iqbal Fuady Ahmad Lathif(3), Ahmad Taufiq(4)
(1) Master Program or Geological Engineering, Gadjah Mada University
(2) Department of Geological Engineering. Gadjah Mada University
(3) Department of Geological Engineering. Gadjah Mada University
(4) Ministry of Public Works and Housing
(*) Corresponding Author
Abstract
Seawater intrusion is a major concern in coastal urban areas like Makassar, where groundwater is a crucial water source. This study assesses seawater intrusion using multiple approaches, including geological and hydrogeological analysis, Cl/Br vs. Cl graphical analysis, recharge area land use, groundwater usage, and previous seawater intrusion vulnerability mapping. From 20 groundwater samples, five were categorized as brackish and then analyzed using these six perspectives. Geologically, two shallow wells in Mariso and Manggala contain brackish water due to trapped marine sediments, supported hydrogeologically by local groundwater flow patterns indicating past shallow seawater traps, while wells in Tallo show no such indications. Cl/Br vs. Cl graphical analysis classifies the shallow well in Tallo as Seawater, one in Manggala as Brine Basin, and three others as landfill leachate, suggesting anthropogenic contamination. Most groundwater recharge areas are residential and built-up, limiting infiltration and contributing to seawater intrusion. Groundwater usage is highest in Tallo, moderately high in Mariso and Manggala, and moderate in Ujung Pandang. Vulnerability mapping places the Tallo well in a high-risk zone, the Mariso well in a low-risk zone, and the Manggala well in a non-vulnerable area. Across these perspectives, only one sample in the Tallo District is confirmed to experience seawater intrusion.
Keywords
Full Text:
PDFReferences
Aller, L., Bennett, T., Lehr, J. H., Petty, R. J., & Hack- ett, G. (1987). DRASTIC: A Standardized System for Evaluating Groundwater Pollution Potential Us- ing Hydrogeologic Settings. Washington, DC: U.S. Environmental Protection Agency.
Amsah, L. O. M. Y. (2020). Identification of the impact of seawater intrusion on groundwater drilling depth using the geoelectric method in Makassar City. Jurnal Akademika, 17(1), 14–17.
Badan Standardisasi Nasional. (2015). SNI 6728.1-2015: Preparation of Water Resources Balance. Jakarta: BSN.
Central Statistics Agency. (2023). Makassar in Figures 2023.
Custodio, E. (1987). Seawater Intrusion in Coastal Aquifers: Guidelines for Study, Monitoring and Con- trol. Paris: UNESCO.
Custodio, E. (2002). Aquifer overexploitation: What does it mean? Hydrogeology Journal, 10(2), 254–277. DOI: 10.1007/s10040-002-0188-6.
Damayanti, A. D., & Notodarmodjo, S. (2021). G- ALDIT and G-ALDITLcR methods for evaluating the vulnerability of shallow groundwater due to seawater intrusion (Case study: Shallow ground- water in the northern and southern coastal areas of Makassar). Journal of Environment and Geological Disasters, 12(2), 107–123.
Domenico, P. A., & Schwartz, F. W. (1998). Physical and Chemical Hydrogeology. Second Edition. New York: John Wiley & Sons, Inc.
Davis, S. N., & De Wiest, R. J. M. (1966). Hydrogeol- ogy. New York: John Wiley & Sons.
Depkimpraswil. (2003). Urban Clean Water Require- ments Standards. Jakarta. ESRI (Environmental Systems Research Institute). (2017-2023). Living Atlas: Land cover. ArcGIS. Retrieved September 20, 2024, from https://livingatlas.arcgis.com/landcover
Famiglietti, J. S. (2014). The global groundwater cri- sis. Nature Climate Change, 4(11), 945–948. DOI: 10.1038/nclimate2425.
Ferguson, G., & Gleeson, T. (2012). Vulnerability of coastal aquifers to groundwater use and cli- mate change. Nature Climate Change, 2(5), 342–345. DOI: 10.1038/nclimate1413.
Foster, S., & Chilton, P. J. (2003). Groundwater: The processes and global significance of aquifer degradation. Philosophical Transactions of the Royal Society B: Biological Sciences, 358(1440), 1957–1972. DOI: 10.1098/rstb.2003.1380.
Galloway, D. L., & Burbey, T. J. (2011). Review: Re- gional land subsidence accompanying groundwa- ter extraction. Hydrogeology Journal, 19(8), 1459–1486. DOI: 10.1007/s10040-011-0775-5.
Hamed, Y., Hadji, R., Redhaounia, B., Zighmi, K., Baali, F., & El Gayar, A. (2018). Climate im pact on surface and groundwater in North Africa: A global synthesis of findings and recommenda- tions. Euro-Mediterranean Journal for Environmen- tal Integration, 3(1), 25. DOI: 10.1007/s41207-018-0067-8.
Hasrianto, Imran, A., Menasye, M., & Afasedanya, T. (2023). Identification of seawater intrusion dis- tribution based on ISO resistivity maps using the geoelectric method in Makassar City. Journal of Engineering AMATA, 4(1), 52–57.
Howard, K. W. F. (2015). Sustainable cities and the groundwater governance challenge. Envi- ronmental Earth Sciences, 73(6), 2543–2554. DOI: 10.1007/s12665-014-3370-y.
IWACO. (1989). Industrial Water Requirements Classi- fication. Retrieved from https://www.rucika.co.id/ peran-air-dalam-kemajuan-industri/
Langkoke, R. (2023). Geospatial Analysis for Delta Evolution of Jeneberang River in Makas- sar, South Sulawesi, Indonesia. Indonesian Journal on Geoscience, 10(2), 151–165. DOI: 10.17014/ijog.10.2.151-165.
Ministry of Agrarian Affairs and Spatial Plan- ning/National Land Agency (ATR/BPN). (n.d.). RTR Online. Retrieved January 21, 2024, from http://gistaru.atrbpn.go.id/rtronline
Nugroho, S. A., Wilopo, W., & Taufiq, A. (2024). Assessment of seawater intrusion based on geo- chemical and isotopic data in Makassar coastal area, South Sulawesi, Indonesia. Journal of De- graded and Mining Lands Management, 12(1), 6563– 6577. DOI: 10.15243/jdmlm.2024.121.6563
Nugroho, S.A. and Taufiq, A. (2025). Determina- tion of Groundwater Recharge Area Based on Isotope Data in Makassar Coastal Area, South Su- lawesi, Indonesia. IOP Conference Series: Earth and Environmental Science, 1451(1), 012001. DOI: 10.1088/1755-1315/1451/1/012001 .
Panno, S. V., Hackley, K. C., Hwang, H. H., Green- berg, S. E., Krapac, I. G., Landsberger, S., & O’Kelly, D. J. O. (2006). Characterization and identification of Na-Cl sources in groundwater. Ground Water, 44(2), 176-187.
Safitri, F. (2016). Vulnerability assessment of un- confined groundwater to seawater intrusion in the coastal area of Makassar city (Master’s thesis, Universitas Gadjah Mada.
Smith, J. (2020). Water Resources and Management. New York: Environmental Publications.
Sukamto, R., & Supriatna, S. (1982). Regional Geo- logical Map of Ujung Pandang-Benteng dan Sin- jai, Sulawesi, Scale 1: 250.000. Center for Geologi- cal Research and Development, Bandung
Syam, M. A. (2015). Groundwater Modeling for Predicting Flow and the Negative Impacts of Groundwater Extraction in Makassar City, South Sulawesi [Thesis]. Graduate Program, Faculty of Engineering, Gadjah Mada University, Yo- gyakarta.
Tirtosudarmo, R. (2017). Groundwater Over- extraction in the Coastal Area of Makassar: A Supply- Demand Analysis. Jakarta: Indonesian Institute of Sciences (LIPI).

Article Metrics


Refbacks
- There are currently no refbacks.
Copyright (c) 2025 Sunu Ardhi Nugroho

This work is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License.
Journal of Applied Geology Indexed by:

This work is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License.