ESTIMASI TRANSPOR SEDIMEN DI PERAIRAN KECAMATAN BREBES, JAWA TENGAH BERDASARKAN LAJU SEDIMENTASI DAN PENDEKATAN MODEL NUMERIK

WISNU ARYA GEMILANG, ULUNG JANTAMA WISHA

DOI: http://dx.doi.org/10.32693/jgk.17.1.2019.552

Abstract


Erosi dan akresi telah menjadi masalah utama di perairan Kecamatan Brebes. Perubahan pesisir yang sangat dinamis dipicu oleh faktor hidro-oseanografi yang mengendalikan mekanisme transpor sedimen yang terjadi baik di muara maupun diwilayah pantai. Tujuan dari penelitian ini adalah untuk mengetahui tingkat rata-rata laju sedimentasi dan transpor sedimen yang terjadi di kawasan pantai Kecamatan Brebes. Pengambilan data laju sedimentasi menggunakan sediment trap yang kemudian dianalisis secara statistik. Perhitungan total transportasi sedimen dan distribusi vertikal suspensi sedimen dilakukan dengan pendekatan model numerik. Nilai laju sedimentasi berkisar antara 0,243 – 22,724 g.m-2.hari-1 dimana laju tertinggi berada di hulu sungai Pemali, Sungai Pemuda dan hilir sungai Pemali. Nilai sortasi sedimen menunjukkan nilai 1,1 – 1,59 (pemilahan buruk). Nilai skewness (Ski) berkisar antara 0,21 – 0,46 (dominan menceng sangat halus). Nilai kurtosis berkisar antara 1,79 – 4,45 (sangat runcing). Total transportasi sedimen sebesar 43,88 x 10-5 m3/s dan distribusi vertikal konsentrasi sedimen tersuspensi berkisar antara 1-176 mg/L (pasang) dan 3-198 mg/L (surut) dimana transpor sedimen sangat dipengaruhi oleh kondisi oseanografi (gelombang, pasang surut, dan arus sepanjang pantai). Pada saat tinggi gelombang pecah meningkat maka transpor sedimen yang terjadi juga semakin intens termasuk mekanisme erosi dan sedimentasi yang terjadi di dasar perairan.

Kata kunci: Laju sedimentasi, model numerik, transpor sedimen, perairan Brebes


Erosion and accretion has become the main issues in Brebes Sub-District waters. Coastal changes which are very dynamic are triggered by hydro-oceanography factors controlling sediment transport mechanism occurred both in the estuary and coastal area. This study aims to determine the average of sedimentation rate and the sediment transport depiction in Brebes Sub-District coast. Sedimentation rate data collection was done using cylinder sediment trap which was then analyzed statistically. Total transport sediment and suspended sediment vertical distribution were calculated employing numerical model approach. The value of sedimentation rate ranged from 0.243 – 22.724 g.m-2.day-1 in which the highest value was observed upstream Pemali River, Pemuda River, and downstream Pemali River. Sediment sortation ranged from 1.1 – 1.59 (poorly sorted). Skewness (Ski) value ranged from 0.21 – 0.46 (very fine skewed). Kurtosis value ranged from 1.79 – 4.45 (very leptokurtic). Total sediment transport reached 43.88 x 10-5 m3/s and vertical distribution of suspended sediment ranged from 1-176 mg/L (flood) and 3-198 mg/L (ebb) respectively wherein the sediment transport is strongly controlled by the oceanography conditions (waves, tidal, and longshore current). When the breaking wave crest enhanced, the sediment transport occurs intensely including erosion and sedimentation in the bottom of water.

Keywords: Sedimentation rate, numerical model, sediment transport, Brebes waters


Keywords


Sedimentation rate;numerical model;sediment transport;Brebes waters

References


Angusamy, N., & Rajamanickam, G. V. 2006. Depositional environment of sediments along the southern coast of Tamil Nadu, India. Oceanologia, 48(1).

Apriyantoro, K., Saputro, S., & Hariadi, H. 2016. Studi Sebaran Sedimen Dasar Di Perairan Muara Sungai Kluwut, Kabupaten Brebes, Jawa Tengah. Journal of Oceanography, 5(4), 435-440.

Braden, G. E. 2015. Turbulence, diffusion and sedimentation in stream channel expansions and contractions. In Proceedings of the Oklahoma Academy of Science (Vol. 31, pp. 73-77) February 2015.

Carol, E., Mas-Pla, J., & Kruse, E. 2013. Interaction between continental and estuarine waters in the wetlands of the northern coastal plain of Samborombón Bay, Argentina. Applied geochemistry, 34, 152-163.https://doi.org/10.1016/j.apgeochem.2013.03.006.

CERC, U. A. 1984. Shore protection manual. US Army Corps of Engineers, Washington.

Cerlyawati, H., Anggoro, S., & Zainuri, M.2017. Strategi Pengelolaan Lingkungan Pada Kawasan Rehabilitasi Mangrove Di Desa Kaliwlingi Brebes, Desa Mojo Pemalang, Dan Desa Bedono, Demak (Doctoral Dissertation, School Of Postgraduate).

Chao, W., Chao, S., Wang, P. F., Jin, Q., Jun, H., & LIU, J. J. 2013. Modeling of sediment and heavy metal transport in Taihu Lake, China.Journal of Hydrodynamics, Ser. B, 25(3), 379-387. https://doi.org/10.1016/S1001-6058(11)60376-5

Disaptono, S., Budiman. 2006. Hidup Akrab Dengan Gempa dan Tsunami. Buku Ilmiah populer, 383.

Docherty, N. J., Chanson, H. 2010. Characterization of Unsteady Turbulence in Breaking Tidal Bores Including the Effects of Bed Roughness. Hydraulic Model Reports. School of Civil Engineering, The University of Queensland, Report CH76/10. 100 pp. https://doi.org/10.1061/(asce)ww.1943-5460.0000048.

Dyer, K., 1986. Coastal and estuarine sediment dynamics. John Wiley And Sons, Chichester, Sussex(Uk), 1986, 358.

Folk R.I dan Ward W.C. 1957. Brazos River bar: a study in the significance of grain size parameters. Journal of Sedimentary Petrology, 27; 3-26p. https://doi.org/10.1306/74d70646-2b21-11d7-8648000102c1865d.

Friedman, G. M. 1967. Dynamic processes and statistical parameters compared for size frequency distribution of beach and river sands.Journal of Sedimentary Research, 37(2), 327-354.https://doi.org/10.1306/74d716cc-2b21-11d7-8648000102c1865d.

Garrett, C., and E. Kunze. 2007. Internal tide generation in the deep ocean.Annu. Rev. Fluid Mech., 39, 57-87. https://doi.org/10.1146/annurev.fluid.39.050905.110227.

Gemilang, W. A., Wisha, U. J., & Rahmawan, G. A. 2018. Particle Size Characteristics of Riverbed Sediment Transported By Tidal Bore" Bono"(Case Study: Kampar Big River Estuary, Riau, Indonesia). Marine Research in Indonesia, 43(1). http://dx.doi.org/10.14203/mri.v43i1.293.

Gemilang, W.A., Kusumah, G., Wisha, U.J. and Arman, A., 2017. Laju Sedimentasi Di Perairan Brebes, Jawa Tengah Menggunakan Metode Isotop 210pb. Jurnal Geologi Kelautan, 15(1).

Gemilang, W.A., Rahmawan, G.A., Dhiauddin, R. and Wisha, U.J., 2018. Karakteristik Sebaran Sedimen Pantai Utara Jawa Studi Kasus: Kecamatan Brebes Jawa Tengah. Jurnal Kelautan Nasional, 13(2), pp.65-74.

Hariadi, A., Satriadi, A., & Subardjo, P. 2017. Laju Sedimentasi Di Muara Sungai Tayu Kabupaten Pati Jawa Tengah. Journal of Oceanography, 6(1), 322-329.

Helfinalis, P., 2010. Hadikusumah (2010). Studi Kelayakan Pembangunan Dermaga di Lingkungan Perairan Pantai Ujung Gebang Indramayu, Laporan Akhir Program Insentif Peneliti dan Perekayasa LIPI tahun.

Hendrarto, B., & Radjasa, O. K. 2015. Pemetaan Degradasi Ekosistem Mangrove dan Abrasi Pantai Berbasis Geographic Information System di Kabupaten Brebes-Jawa Tengah.OSEATEK,9(01).

Hutabarat, T. 2017. Aplikasi Dating Pb-210 Untuk Estimasi Laju Sedimentasi Muara Cigede Dan Ciomas Pada Daerah Tangkapan Waduk Malahayu-Brebes. Ilmu Dan Budaya, 40(49).

Irudhayanathan, A., Thirunavukkarasu, R. and Senapathi, V., 2011. Grain size characteristics of the Coleroon estuary sediments, Tamilnadu, East coast of India. carpathian journal of earth and environmental sciences, 6(2), p.151157.

Kumar, G., Ramanathan, A. L., & Rajkumar, K. 2010. Textural characteristics of the surface sediments of a Tropical mangrove ecosystem Gulf of Kachchh, Gujarat, India. Indian Journal of Marine Sciences, 39(3), 415-422p.

Lanuru, M. and Yusuf, S., 2018. Bed sediment distribution in the river estuary and coastal sea of Malili (South Sulawesi, Indonesia). Jurnal Ilmu Kelautan SPERMONDE, 4(2).

Marfai, M. A. 2017. The hazards of coastal erosion in Central Java, Indonesia: An overview. Geografia-Malaysian Journal of Society and Space, 7(3).

Nugroho, S. H., & Basit, A. 2014. Sebaran sedimen berdasarkan analisis ukuran butir di Teluk Weda, Maluku Utara. Jurnal Ilmu dan Teknologi Kelautan Tropis, 6(1), 229-240.http://dx.doi.org/10.29244/jitkt.v6i1.8644.

Ondara, K., & Wisha, U. J. 2016. Simulasi Numerik Gelombang (Spectral Waves) dan Bencana Rob Menggunakan Flexible Mesh dan Data Elevation Model Di Perairan Kecamatan Sayung, Demak.Jurnal Kelautan: Indonesian Journal of Marine Science and Technology, 9(2), 164-174.https://doi.org/10.21107/jk.v9i2.1694.

Ondara, K., Rahmawan, G. A., Gemilang, W. A., Wisha, U. J., & Dhiauddin, R. 2018. Numerical Hydrodynamic Wave Modelling Using Spatial Discretization in Brebes Waters, Central Java, Indonesia. International Journal on Advanced Science, Engineering and Information Technology, 8(1), 257-263.https://doi.org/10.18517/ijaseit.8.1.4166.

Pranoto, H. R., & Atmodjo, W. 2016. Studi Sedimentasi pada Bangunan Groin di Perairan Timbulsloko, Kabupaten Demak.Journal of Oceanography, 5(1), 86-95.

Qi, W. G., & Gao, F. P. 2014. Physical modeling of local scour development around a large-diameter monopile in combined waves and current.Coastal Engineering,83, 72-81. https://doi.org/10.1016/j.coastaleng.2013.10.007.

Reid, L. and Dunne, T., 2016. Sediment budgets as an organizing framework in fluvial geomorphology. In: Kondolf, GM; Piégay, H., eds. Tools in Fluvial Geomorphology. Chichester, UK: John Wiley & Sons, Ltd: 357-379. Chapter 16, pp.357-379.

Sardiyatmo, S., Supriharyono, S., & Hartoko, A. 2013. Dampak Dinamika Garis Pantai Menggunakan Citra Satelit Multi Temporal Pantai Semarang Provinsi Jawa Tengah (Study Of The Dynamics Of Image Using Satellite Beach Line Multi-Temporal Beach Semarang Central Java Province).Saintek Perikanan: Indonesian Journal Of Fisheries Science And Technology, 8(2), 33-37.https://doi.org/10.14710/ijfst.8.2.33-37.

Setiyarso, B., Muryani, C., & Sarwono, S. 2016. Analisis Perubahan Garis Pantai Dan Perubahan Penggunaan Lahan Kabupaten Rembang Tahun 2003-2014.GeoEco,2(1).

Thom, B.G., Eliot, I., Eliot, M., Harvey, N., Rissik, D., Sharples, C., Short, A.D. and Woodroffe, C.D., 2018. National sediment compartment framework for Australian coastal management. Ocean & coastal management, 154, pp.103-120.

Triatmodjo, B. 2012. Coastal Building Planning. Beta Offset. Yogyakarta. Indonesia.

Warner, J. C., B. Armstrong, R. He, and J.B. Zambon. 2010. Development of a coupled ocean–atmosphere–wave–sediment transport (COAWST) modeling system.Ocean Modelling, 35(3), 230-244. https://doi.org/10.1016/j.ocemod.2010.07.010.

Wisha, U. J., Al Tanto, T., Pranowo, W. S., & Husrin, S. 2017. Current movement in Benoa Bay water, Bali, Indonesia: Pattern of tidal current changes simulated for the condition before, during, and after reclamation. Regional Studies in Marine Science,18, 177-187.https://doi.org/10.1016/j.rsma.2017.10.006.

Wisha, U.J. and Heriati, A., 2016. Analisis Julat Pasang Surut (Tidal Range) dan pengaruhnya terhadap Sebaran Total Sedimen Tersuspensi (TSS) di Perairan Teluk Pare. Jurnal Kelautan: Indonesian Journal of Marine Science and Technology, 9(1), pp.23-31.




DOI: http://dx.doi.org/10.32693/jgk.17.1.2019.552

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