Study of Seawater Intrusion in Deep Aquifers of Semarang Coast Using Natural Isotopes and Hydrochemicals
DOI:
https://doi.org/10.17014/ijog.6.1.17-28Keywords:
seawater intrusion, natural isotopes, hydrochemical, deep aquifer, SemarangAbstract
DOI: 10.17014/ijog.6.1.17-28
Seawater intrusion in deep aquifers of Semarang Coast is important to be investigated, because Semarang is one of big cities in Indonesia. Besides its dense population, the growth of industries also increases rapidly with the increase of withdrawal of groundwater either from shallow or deep aquifers. Over-exploitation of groundwater can cause a decreasing groundwater quality due to seawater intrusion. Through this study, the salinization from seawater into the deep aquifer system can be observed. Groundwater samples were collected from deep aquifers with the depth around 40-120 m, and then the isotope contents of 18O and 2H as well as the hydrochemical were analyzed. The isotope and hydrochemical analysis results show that six of thirteen samples are of freshwater type. They are in S2, S5, S7, S8, S9, and S13 sites. While the others are supposed to be encroached by seawater. The slight encroached groundwater of S1, S6, and S10 had a fraction of seawater in the range of 0.15 to 0.26, whereas the moderate and high ones were of S3, S4, S11, and S12 which had seawater fraction between 0.25 and 0.34. Seemingly, salinization mechanism of groundwater by seawater does not depend on its distance from the shoreline and bore well depth. It is confirmed to the site of S5 and S7 located 680 m and 950 m from the shoreline, respectively, which were predominated as freshwater type. On the contrary, the groundwater of S10, S11, and S12 located at further sites about 5-6 km from shoreline is clearly indicated seawater intrusion.
References
Babu, M.M., Viswanadh, G.K., and Rao, S.V., 2013. Assessment of Saltwater Intrusion Along Coastal Areas of Nellore District, A.P., 4 (7), 173-178.
Bhandary, H., Al-Fahad, K., and Al-Senafy, M., 2013. Assesment Of Water Rise Problem Using Environmental Isotopes At Al-Quran Residential Area, Kuwait. 17th International Water Technology Conference, IWTC17, 5-7, November 2013.
Ekhmaj, A., Ezlit, Y., and Elaalem, M., 2014. The Situation of Seawater Intrusion in Tripoli, Libya, International Conference on Biological. Chemical and Environmental Sciences (BCES-2014) June 14-15, 2014 Penang (Malaysia), p.1-6. DOI: 10.15242/iicbe.c614007
Fahrudin and Najib, 2011. Study of The Piezometric Surface and Hydrocompaction At Confined Aquifer Caused The Land Subsidence In Semarang, TEKNIK, 32 (1), p.72-78.
Gaj, M., Beyer, M., Koeniger, P., Wanke, H., Hamutoko, J., and Himmelsbach, T., 2015. In-situ unsaturated zone stable water isotope (2H and 18O) measurements in semi-arid environments using tunable off-axis integrated cavity output spectroscopy. Hydrology and Earth System Sciences, 12, p.6115-6149. DOI: 10.5194/hessd-12-6115-2015
Gaye, C.B., 2001. Isotope techniques for monitoring groundwater salinization. 1st International Conference on Saltwater Intrusion and Coastal Aquifers, Monitoring, Modeling, and Management. Essaouira, Morocco, April p.23-25.
Hamed, Y., 2014. Earth Science & Climatic Change Stable Isotope Ratios in Meteoric Waters in El Kef Region, Northwestern Tunisia: Implications for Changes of Moisture Sources. Earth Science & Climatic Change, 5(6), p.1-6. DOI: 10.4172/2157-7617.1000203
Katrinavia, Y.P., Setyawan, A., and Supriyadi, 2015. Pemodelan Anomali Gaya Berat Akibat Curah Hujan dan Dinamika Air Tanah di Daerah Semarang. Jurnal Fisika Indonesia, 19, p.42-44.
Klassen, J., Allen, D.M., and Kirste, D., 2014. Chemical Indicators of Saltwater Intrusion for the Gulf Islands, British Columbia, Final Report, Department of Earth Sciences, Simon Fraser University.
Latifiani, D. and Widyawati, A., 2011. Peningkatan Penyadaran Hukum Tentang Pencemaran Air Bawah Tanah Akibat Intrusi Air Laut di Kel. Dadapsari Kota Semarang. ABDIMAS, 15 (2), p.66-74.
Mamlucky, S. and Harnadi, D., 2007. Penelitian Hidrogeologi Daerah Imbuhan Air Tanah Dengan Metode Isotop dan Hidrokimia di Cekungan Air Tanah Semarang - Demak, Propinsi Jawa Tengah. Pusat Lingkungan Geologi Bandung.
Nathenson, M., 2013. Review of: Mongelli, G., Monni, S., Oggiano, G., Paternoster, M., and Sinisi, R., 2013, Tracing groundwater salinization processes in coastal aquifers: a hydrogeochemical and isotopic approach in Na-Cl brackish waters of north-western Sardinia, Italy. Hydrology and Earth System Sciences Discussions, 10, p.1041-1070. U.S. Geological Survey. DOI: 10.5194/hess-17-2917-2013
Pasaribu, M., 2003. Pemantauan Kuantitas Dan Kualitas Airtanah Cekungan Airtanah Semarang-Demak. Direktorat Geologi Tata
Lingkungan dan Kawasan Pertambangan (DEG). Bandung.
Prasetio, R. and Satrio, 2015. Aplikasi teknik isotop alam 18O dan 2H untuk studi air tanah pada cekungan airtanah Semarang, Jawa Tengah. Prosiding Pertemuan dan Presentasi Ilmiah - Penelitian Dasar Ilmu Pengetahuan dan Teknologi Nuklir 2015 Pusat Sains dan Teknologi Akselerator - BATAN Yogyakarta, 9 -10 Juni 2015, p.46-51. DOI: 10.17146/jair.2016.12.2.3545
Putranto, T.T. and Rüde, T.R., 2011. Hydrogeology of Semarang Demak Groundwater Basin: An Overview and its Challenges in
Preliminary Groundwater Flow Modeling. Proceedings JCM Makassar, The 36th HAGI and 40th IAGI Annual Convention and Exhibition Makassar.
RKPD Kota Semarang, 2012. Peraturan Walikota Semarang Nomor 16 Tahun 2012 Tentang Rencana Kerja Pembangunan Daerah (RKPD) Kota Semarang Tahun 2013.
RKPD Kota Semarang, 2014. Peraturan Walikota Semarang Nomor 18 Tahun 2014 Tentang Rencana Kerja Pembangunan Daerah (RKPD) Kota Semarang Tahun 2015.
Satrio, Hendarmawan, Hadian, S.D.H., and Indiyati, E.R.P., 2014. Karakteristik Air Tanah Dangkal Kota Semarang Pada Musim
Penghujan Berdasarkan Pendekatan Isotop Stabil (18O, 2H ) dan Kimia Air. Jurnal Ilmiah Aplikasi Isotop dan Radiasi, 11(1), p.73-86.
DOI: 10.17146/jair.2015.11.1.2701
Satrio and Sidauruk, P., 2015. Studi Daerah Imbuh Sistem Air Sungai Bawah Tanah Gunungkidul, Yogyakarta, Menggunakan Isotop Stabil δ18O dan δ2H. Jurnal Ilmiah Aplikasi Isotop dan Radiasi, 11(2), p.87-98. DOI: 10.17146/jair.2015.11.2.2986
Satrio, Prasetio, R., Hadian, M.S.D., and Syafri, I., 2017. Stable Isotopes and Hydrochemistry Approach for Determining the Salinization Pattern of Shallow Groundwater in Alluvium Deposit Semarang, Central Java, 4(1), p.1-10. DOI: 10.17014/ijog.4.1.1-10
Sihwanto, M., Heddy, S., and Arifin, B., 1988. Groundwater Potential Survey In Semarang And Its Surrounding Area. Report No. 03/HGKA/1988. Direktorat Geologi Tata Lingkungan (DEG). Bandung.
Sola, F., Vallejos, A., Moreno, L., Geta, J.A.L, and Bosch, A.P., 2013. Identification of hydrogeochemical process linked to marine intrusion induced by pumping of a semiconfined Mediterranean
coastal aquifer. International Journal of Environmental Science Technology, 10, p.63-76. DOI: 10.1007/s13762-012-0087-x
Sudaryanto, Delinom, R.M., Suherman, D., and Lubis, R.F., 2014. Gangguan Air Laut terhadap Kondisi Air Tanah di Wilayah Semarang, Jawa Tengah. Majalah Geologi Indonesia, 29 (2), p.101-113.
Suhartono, E., Purwanto, and Suripin, 2013. Kondisi Intrusi Air Laut Terhadap Air Tanah Pada Akuifer di Kota Semarang. Prosiding Seminar Nasional Pengelolaan Sumberdaya Alam Dan Lingkungan, p.396-401.
Susanto, A., Rusdianto, and Sawir, I., 2015. Model Konservasi Pemanfaatan Air Tanah Yang Berkelanjutan Di Kota Semarang. Jurnal Matematika, Saint, dan Teknologi, 15(1), p.29-41.
Vernier Software & Technology, 2014. Chloride and Salinity, p.1-9.
Wardhana, D.D., Harjono, H., and Sudaryanto, 2014. Struktur Bawah Permukaan Kota Semarang Berdasarkan Data Gayaberat. RISET Geologi dan Pertambangan, 24 (1), p.53-64. DOI: 10.14203/risetgeotam2014.v24.81
West, A.G., February, E.C., and Bowen, G.J., 2014. Spatial analysis of hydrogen and oxygen stable isotopes (“isoscapes”) in groundwater and tap water across South Africa. Journal of Geochemical Exploration, 145, p.213-222. https://doi.org/10.1016/j.gexplo.2014.06.009. DOI.org/10.1016/j.gexplo.2014.06.009.
Yang, L., Song, X., Zhang, Y., Han, D., Zhang, B., and Long, D., 2012. Characterizing interactions between surface water and groundwater in the Jialu River basin using major ion chemistry and stable isotopes. Hydrology, and Earth System Sciences, 26, p.4265-4277. DOI: 10.5194/hess-16-4265-2012
