Potential debris flow of the Tuva River in Sigi Regency, Central Sulawesi Province
Abstract
Flash floods/debris floods that occur in the Tuva River of Sigi Regency are streams of water mixed with various materials such as wood, rocks, mud, and others that have a very fast flow speed. Flash floods submerged the residential area of the community with a water presence of 3 m which had claimed the lives of 2 people. Flash floods occur after catastrophic earthquakes and soil liquefaction. Where the topographic conditions around the Tuva River are very steep and the characteristics of the river widens upstream and narrows downstream, there is the potential for avalanches of liquefaction of mountain ridge land that enters the river which forms a natural weir in the Tuva River. The modeling conducted in this research utilized a Digital Elevation Model (DEM) map with a resolution of 5-10 meters using Hec-RAS software. The modeling focused on the dam break of a natural dam, resulting in a debris flow volume of 104.663 m3/s. With the non-Newtonian flow model, the study determined a flooded area of 58.978 hectares or 0.589 square kilometers with a maximum flow velocity of 2645.33 m/s. This has the potential to erode the riverbed and supply sediment transport to the Miu River.
References
Hermawan. Banjir bandang di Indonesia. Badan Geologi. Pusat lingkungan geologi bandung. 2007.
BMKG. Ulasan Guncangan Tanah Akibat Gempa Bumi Utara Donggala Sulteng,28 September 2018, Bidang Seismologi Teknik-BMKG.https://cdn.bmkg.go.id/Web/UlasanGempaDONGGALA_28092018_rev13102018.pdf (diunduh 20 Maret 2023).
BPBD. Dinas Kesehatan Kab. Sigi. Banjir bandang di sigi 12-12-2019. https://pusatkrisis.kemkes.go.id/Banjir-Bandang-di-SIGI-SULAWESI-TENGAH-12-12-2019-37
Cui, P. Chen, X., Waqng, Y., Hu, K., & Li, Y., Jiangjia Ravine debris flows in south-western China, Springer: in Debris-flow hazards and related phenomena, pp. 565-594, 2005.
Rosli, M.I., Che Ros, F., Razak, K.A., Ambran, S., Kamaruddin, S.A., Nor Anuar, A., Marto, A., Tobita, T., Ono, Y., Modelling debris flow runout: a case study on the Mesilau Watershed, Kundasang, Sabah. Water, 13 (19), p. 2667, 2021.
Syarifuddin, M., Oishi, S., Legono, D., Hapsari, R.I. and Iguchi, M., Integrating X-MP radar data to estimate rainfall-induced debris flow in the Merapi volcanic area, Advances in water res., 110, pp. 249-262, 2017.
Lavigne, F. & Thouret, J. C., Sediment transportation and deposition by rain-triggered lahars at Merapi Volcano, Central Java, Indonesia, Geomorphology, 49 (2), pp. 45-69, 2003.
Sukatja C Bambang. dkk. Mitigasi penanggulangan bencana banjir debris pasca gempa palu 2018, Jurnal Teknik Hidraulik, vol.12,no.1,Juni 2021
King, H. M., 2011, What is a Debris Flow ?, https://geology.com/articles/debris-flow/, diakses tgl 01 Mei 2023.
Takahashi, T., Debris flow, mechanics, prediction and countermeasures, ed.1, Taylor & Francis/Balkema, 2007.
Gregoretti, C. & Fontana, G. D., The triggering of debris flow due to channel-bed failure in some alpine headwater basins of the dolomites: analyses of critical runoff, Hydrological Processes: An International Journal, 22(13), pp. 2248-2263, Oct. 2007.
HEC., HEC-RAS 2D user’s manual v6.1, Available online:https://www.hec.usace.army.mil/confluence/rasdocs/r2dum/latest (accessed on 03 Maret 2023).
Badan Informasi Geospesial. Digital Elevation Model Nasional dengan resolusi 5-10 m, tahun 2021. Diakses dari https://tanahair.indonesia.go.id/demnas/#/demnas.
Zahroni Aulia., Kajian Efektifitas Pengendalian Sedimen Sungai Yeh Sah Pasca Erupsi Gunung Agung pada 2017-2019 di Provinsi Bali, Thesis Magister Program of Water Resources Management, ITB, Bandung.2022.
Zahroni, A., Harlan, D. Soentoro, E., Nugroho, E.O., Aprillian, Z., Analysis Curve Number Value to Estimate Debris Flow in the Mount Agung Volcanic Area, Bali, Indonesia., 3rd IGSC Conference, ITB, 21 Dec 2022.
J. Cahyono, "Teori Aliran Puing," [Online]. Tersedia: http://jcpoweryogyakarta.blogspot.com/, . [Diakses 2023].
B. Scharffenberg, M. Bartles, T. Brauer, M. Fleming, dan G. Karlovits, "Sistem Pemodelan Hidrologi HEC-HMS, Panduan Pengguna.," Pusat Teknik Hidrologi. Institut Korps Insinyur Angkatan Darat AS untuk Pusat Teknik Hidrologi Sumber Daya Air, Davis, CA, hlm. 640, 2018, [Online].
S. Gibson dan A. Sánchez, "Manual aliran HEC-RAS, Lumpur dan Puing," Institut Korps Insinyur Angkatan Darat AS untuk Pusat Teknik Hidrologi Sumber Daya Air, Davis, CA, hlm. 58, 2020.
S. Hergarten dan J. Robl, "Pemodelan gerakan massa cepat menggunakan persamaan air dangkal dalam koordinat Cartesian," Nat. Bahaya Bumi Syst. Sci., vol. 15, no. 3, hlm. 671–685, 2015, doi: 10.5194 / nhess-15-671-2015.
Bozhinskiy dan A. N. Nazarov, "Model dua fase aliran puing," dalam 2nd Int. Conf. on Debris-Flow Hazards Mitigation: Mechanics, Prediction, and Assessment., 2000, hlm. 263–269.
S. Gibson dkk. , "Evaluasi Skala Prototipe Algoritma Non-Newtonian di HEC-RAS: Lumpur dan Aliran Puing Studi Kasus Santa Barbara dan Brumadinho," Geosciences (Swiss), vol. 12, no. 3, 2022, doi: 10.3390/geosciences12030134.
Hadiranti., Sueharno,A.W.H., Prasetyo, A., Nugroho, E.O., Putranto, A.E., The Prediction Of Debris Flow Based On Eruption and Rainfall Event For River Infrastructure Mitigation: Study Case Opak River, Sleman Regency., 3rd IGSC Conference, ITB, 21 Dec 2022.
Alfianto, A., Iswardoyo, J., & Sukatja, C. B., Efektivitas dan Kelengkapan Bangunan Sabo di Sungai Togurara Daerah Gunungapi Gamalama, Jurnal Teknik Hidraulik, 10(2),90 –103. 2019.
