Kehadiran Gelombang Soliter dan Transpor Sesaat Sedimen tersuspensi di Perairan Pantai Bengkulu Tengah

Edi Kusmanto; Muhammad Hasanudin

doi:10.14203/oldi.2019.v4i3.262

Kehadiran Gelombang Soliter dan Transpor Sesaat Sedimen tersuspensi di Perairan Pantai Bengkulu Tengah

Edi Kusmanto, Muhammad Hasanudin

Abstract

Existence of Solitary Waves and Transient Suspended Sediment Transport in the Coastal Waters of Central Bengkulu. Coastal abrasion and suspended sediment transport driven by waves is occurring dreadfully in the coastal waters of Central Bengkulu. The abrasion tends to be accelerated by solitary waves during the southeast monsoon season. The primary data were obtained on 17-26 July 2014, while the secondary data derived from Google Maps imageries obtained on 17 June 2014, representing the southeast monsoon season. The primary data were collected by 1200 KHz Acoustic Doppler Current Profiler (ADCP) for water currents, a single beam Echosounder for depths, Garmin 276C GPS receiver for coordinate positions, RBR-TWR2050 (installed at at a fixed point at 102.2219 °E and 3.6916 °S and depth of 9 m) for height and wave periods, and a compass for the direction of wave propagation. The secondary data included Astrium satellite imageries compiled by Google Earth and displayed as Google Maps images on 17 June 2014. These images were used for identifying the appearance of wave groups and by using a feature in Google Earth, it showed that the estimated distance between wave packets hitting the coast accounted for 147 m. This study showed the existence of solitary waves with height and wave period of 1.02 m and 13.85 seconds respectively, while the wave length reached 147.7 m. The wave energy and wave energy flux were 1123.12 Jm^-2 and 12018.94 Jm^-1s^-1, calculated by using the cnoidal wave theory and solved by the KdV equation. These solitary waves have large destructive forces on unstable cliffs along the coasts. Derived from coastal abrasion processes and shown by the ADCP backscatter intensity with the highest of 146 dB, the suspended sediments were likely to be transported by water currents with an average speed of 25.99 cm s^-1 in the dominant direction to the south - southeast; and the sediments were deposited along the coast of Bengkulu City.

10.14203/oldi.2019.v4i3.262

Keywords

Solitary waves, suspended sediment, transport, Central Bengkulu , abrasion.

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References

Ali, A., & Kalisch, H. (2014). On the formulation of mass, momentum and energy conservation in the KdV equation, Journal of Acta Appl. Math., 133(1), 113–131. DOI 10.1007/s10440-013-9861-0.

Anonim (1984). Shore Protection Manual Volume 1. Coastal Engineering Research Center, Department of the Army, Waterways Experiment Station, Corps of Engineers, PO Box 631, Vicksburg, Mississippi, 39180, Washington DC 201314. 337 pp.

Barth, H. & Hilf, E.R. (1995). Solitary wave calculations for erosion strength. Oldenburg, Germany, Carl von Ossietzky Universiteit Oldenburg.

Carter, C. H. & Guy, D. E. (1988). Coastal erosion: Processes, timing and magnitudes at the bluff toe, Journal of Marine Geology, 84(1-2), 1–17.

Dodd, R. K. (1982). Soliton and Non Linear Wave Equations. New York: Academic Press. 630 pp.

Drazin, P. G. & Johnson, R. S. (1989). Soliton: An Introduction. New York: Cambridge University Press. 226 pp.

Dwinovantyo, A., Manik, H. M., Tri, P., & Susilohadi. (2017). Quantification and Analysis of Suspended Sediments Concentration Using Mobile and Static Acoustic Doppler Current Profiler Instruments. Journal of Advances in Acoustics and Vibration, 1-14, DOI 10.1155/2017/4890421.

Fadilah, S. & Dwi, P. S. (2013). Identifikasi Kerusakan Pantai Kabupaten Bengkulu Tengah, Provinsi Bengkulu, Prosiding Seminar Nasional Pengelolaan Sumberdaya Alam dan Lingkungan, 337-341. Semarang, Indonesia.

Hasanudin, M. & Kusmanto, E. (2018). Abrasi dan Sedimentasi Pantai di Kawasan Pesisir Kota Bengkulu. Oseanologi dan Limnologi di Indonesia, 3(3), 245-252. DOI 10.14203/oldi. 2018.v3i3.197.

Holthuijsen, L. H. (2007). Waves in Oceanic and Coastal Waters. Delft University of Technology and UNESCO-IHE. Cambridge University Press, The Edinburgh Building, Cambridge CB2 8RU, UK, 387 pp.

JaeNam, C, Kyu, N. H. & Seung, O. L. (2017). Experimental Assessment of Suspended Sediment Concentration Changed by Solitary Wave, Journal of Marine Science and Technology, 25(6), 649-655.

Kendon, E.J., Roberts, N.M., Fowler H.J., Roberts, M.J., Chan, S.C., & Senior, C.A. (2014). Heavier Summer Downpours with Climate Change Revealed by Weather Forecast Resolution Model, Journal of National Climate Changes, 4, 570–576.

Khorsand, Z. & Henrik, K. (2014). On the Shoaling of Solitary Waves in the KdV Equation, Coastal Engineering Proceedings: Proceedings of 34th Conference on Coastal Engineering Seoul Korea (1-10). Korea.

Lamb, K. G. & Nguyen, V. T. (2009). Calculating Energy Flux in Internal Solitary Waves with an Application to Reflectance, Journal of Physical Oceanography, 559-580. DOI: 10.1175/2008JPO3882.1.

McCormic, M. E. M. (2007). Ocean Wave Energy Conversion, John Wiley & sons, Inc., New York.

Onea, F. & Rusu, E. (2019). The Expected Shoreline Effect of a Marine Energy Farm Operating Close to Sardinia Island. Journal of Water, 11(2303), 1-20. DOI 10.3390/w11112303.

Suwarsono (2011). Zonasi Karakteristik Kecepatan Abrasi dan Rancangan Teknik Penanganan Jalan Lintas Barat Bengkulu Bagian Utara sebagai Jalur Transportasi Vital. Jurnal Makara Teknologi, 15 (1), 31-38.

Wang, Q.S., Li, M. H., & Li, D. W., (2018). Solitary Wave Generation and Propagation under Hypergravity Fields. Journal of Water, 10 (1381), 1-18. DOI 10.3390/w10101381.

Website Resmi Pemerintah daerah provinsi Bengkulu. (2013). Letak Geografis dan iklim, http://bengkuluprov.go.id/ver1/. diakses 12 Desember 2018.

Wibowo, A.Y. (2012). Makalah: Dinamika Pantai (Abrasi dan Sedimentasi). Fakultas Teknik dan Ilmu Kelautan. Universitas Hang Tuah. Surabaya, 1-16.

Yu, H. C. & Hwung, H. H. (2006). Experiments on the Run-up of Solitary Waves over Sloping Bottoms. Third Chinese-German Joint Symposium on Coastal and Ocean Engineering, (pp. 1-14). National Cheng Kung University, Tainan.