Assessment of Flood Discharge Using the HSS SCS–CN Method and Implications for Adaptive Sabo Dam Design in the Saluki River
Abstract
In 2018, the Saluki River was morphologically altered due to 7.4 magnitude earthquake. The changes necessitated an evaluation of post-earthquake hydrological conditions prior to Sabo Dam planning. This study aims to estimate the design flood discharge and assess its implications for the preliminary design of a Sabo Dam in Saluki River. Design flood discharge was estimated using the Soil Conservation Service – Curve Number Synthetic Unit Hydrograph (SCS-CN) method. The model results were calibrated using bankfull discharge measured directly. A sensitivity analysis of the CN parameter was performed with ±10% variation to evaluate the effect of post-earthquake changes on peak flood discharge. The design flood discharge was 102.3 m³/s for the 2-year return period (Q2), 143.9 m³/s (Q5), 173.7 m³/s (Q10), 212.8 m³/s (Q25), 244.8 m³/s (Q50), and 272.8 m³/s (Q100). The SCS-CN simulation results deviate only 0.15% from the observed bankfull discharge, indicating that the selected hydrological parameters is in agreement with the characteristics of local rainfall-runoff process and catchment areas in the region. The sensitivity test revealed that a 10% increase in the CN value resulted in a 40% increase in the Q2 peak discharge, while a 10% decrease led to 30% reduction. The Q100 discharge of 272.8 m³/s was adopted as the capacity of Sabo Dam design. In conclusion, SCS–CN method remains applicable for watershed conditions analysis in areas which its morphological changes affected by earthquakes. However, the reliability of the model is constrained by limited field observations and potential uncertainties in CN parameter estimation.
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Ahilan, S., O’Sullivan, J.J., Bruen, M., Brauders, N., & Healy, D. (2013). Bankfull discharge and recurrence intervals in Irish rivers floods. Proceedings of the ICE – Water Management, 166(7), 381–393. https://doi.org/10.1680/wama.11.00078
Alfianto, A., Cecilia, S., Hidayah, A.N., Anjelita., & Sukatja, C.B. (2021). Perencanaan sabo untuk mengendalikan laju sedimentasi di Rawapening. Jurnal Sumber Daya Air, 17(1), 1-12. https://doi.org/10.32679/jsda.v17i1.610
Balai Wilayah Sungai Sulawesi III Palu. (2023). Pola pengelolaan sumber daya air wilayah Sungai Palu–Lariang. Kementerian Pekerjaan Umum dan Perumahan Rakyat.
Cantik, B.K.P., Sapan, E.G.A., Ghiffari, M.R.A., Yuvhendmindo, M.R., & Aziz, M.L. (2022). Surface runoff analysis using SCS-CN method in Summarecon Serpong area. INERSIA Informasi dan Ekspose Hasil Riset Teknik Sipil dan Arsitektur, 18(2), 94–103. https://doi.org/10.21831/inersia.v18i2.53248
Chow, V.T. (1959). Open-Channel Hydraulics. McGraw-Hill.
Djudi, D., Hassan, C., Soewarno, S., Yunita, F.T., & Gardiawan, G.R. (2014). Stabilitas Pondasi Mengambang Sabodam (Kegiatan Litbang) (Issue 022). Pusat Penelitian dan Pengembangan Sumber Daya Air, Kementerian Pekerjaan Umum dan Perumahan Rakyat.
Gumbel, E.J. (1941). The return period of flood flows. The Annals of Mathematical Statistics, 12(2), 163–190. https://www.jstor.org/stable/2235766
Hosseini, S.M., & Mahjouri, N. (2018). Sensitivity and fuzzy uncertainty analyses in the determination of SCS-CN parameters from rainfall–runoff data. Hydrological Sciences Journal, 63(3), 457–473. https://doi.org/10.1080/02626667.2018.1437272
Jin, W., Cui, P., Zhang, G., Wang, J., Zhang, Y., & Zhang, P. (2023). Evaluating the post-earthquake landslides sediment supply capacity for debris flows. CATENA, 220, 106649. https://doi.org/10.1016/j.catena.2022.106649
Kousari, M.R., Malekinezhad, H., Ahani, H., & Asadi Zarch, M.A. (2010). Sensitivity analysis and impact quantification of the main factors affecting peak discharge in the SCS curve number method: An analysis of Iranian watersheds. Quaternary International, 226(1–2), 66–74. https://doi.org/10.1016/j.quaint.2010.05.011
Kozak, K. (2021). Statistics Using Technology (2nd ed.). Coconino Community College. Lulu.com. ISBN: 9781329757257
Kusumah, A.W., Solikhin, A., Andiani, Anjar, H., Omang, A., Soehami, A., Cipta, A., Defrizal, Yuwana, D.A., Firdaus, E.R., Fadli, Djunursyah, G.M.L., Hasibuan, G., Afif, H., Santosa, I., P., I.E., Sulistyawan, I.H., Kurniah, Falah, N., … Yunara, D.T. (2018). Di Balik Pesona Palu: Bencana Melanda, Geologi Menata. Badan Geologi, Kementerian Energi dan Sumber Daya Mineral.
Layaliya, H.N. (2025). Kajian morfologi sungai akibat bangunan pengendali sedimen dan river improvement di Sungai Namo Kabupaten Sigi. [Master’s Thesis], Institut Teknologi Bandung.
Massey, F.J. (1951). The Kolmogorov–Smirnov test for goodness of fit. Journal of the American Statistical Association, 46(253), 68–78. https://doi.org/10.1080/01621459.1951.10500769
Mouri, G., Golosov, V., Chalov, S., Belyaev, V., Shiiba, M., Hori, T., Shinoda, S., & Oki, T. (2013). Assessing the effects of consecutive sediment-control dams using a numerical hydraulic experiment to model river-bed variation. CATENA, 104, 174–185. https://doi.org/10.1016/j.catena.2012.11.008
Mulvihill, C.I., Baldigo, B.P., Miller, S.J., DeKoskie, D., & DuBois, J. (2009). Bankfull discharge and channel characteristics of streams in New York State (Scientific Investigations Report 2009–5144). U.S. Geological Survey.
Nakano, D., Suzuki, J., Fujita, K., & Imamura, M. (2024). Restoration effects of sediment supply by sediment sluicing dam operations on macroinvertebrate assemblages in the Mimi River, Japan. Ecological Engineering, 206, 107336. https://doi.org/10.1016/j.ecoleng.2024.107336
Natakusumah, D.K., Hatmoko, W., & Harlan, D. (2011). Prosedur umum perhitungan hidrograf satuan sintetis dengan cara ITB dan beberapa contoh penerapannya. Jurnal Teknik Sipil, 18(3). https://doi.org/10.5614/jts.2011.18.3.6
Putranto, A.E., Adityawan, M.B., Moerwanto, A.S., & Natakusumah, D.K. (2024). Analysis of the effectiveness of sediment control structures and river improvement on the Omu River post-earthquake in Sigi Regency. Jurnal Teknik Sumber Daya Air, 15(1). https://doi.org/10.32679/jth.v15i1.749
Robot, J.A., Mananoma, T., Wuisan, E.M., & Tangkudung, H. (2014). Analisis debit banjir Sungai Ranoyapo menggunakan metode HSS Gama-I dan HSS Limantara. Jurnal Sipil Statik, 2(1).
Sari, A.N.S., Pranoto, R., & Suryan, V. (2020). Perhitungan hidrograf banjir dengan metode hidrograf satuan sintesis SCS (Soil Conservation Service) di Kota Palembang. Journal of Airport Engineering Technology, 1(1). https://doi.org/10.52989/jaet.v1i1.1
Shrestha, S., Cui, S., Xu, L., Wang, L., Manandhar, B., & Ding, S. (2021). Impact of land use change due to urbanisation on surface runoff using GIS-based SCS–CN method: A case study of Xiamen City, China. Land, 10(8), 839. https://doi.org/10.3390/land10080839
Sukatja, C.B., W.R., B., & Bahri, P. (2021). Mitigasi dan penanggulangan bencana banjir debris pasca Gempa Palu 2018. Jurnal Teknik Hidraulik, 12(1). https://doi.org/10.32679/jth.v12i1.648
Sun, Q., & Liu, J. (2025). The impact of rainfall value on the accuracy of the SCS-CN model: Selection of model parameters. AQUA: Water Infrastructure, Ecosystems and Society, 74(1), 142–158. https://doi.org/10.2166/aqua.2024.288
Takahashi, T. (2007). Debris flow: Mechanics, prediction and countermeasures (1st ed.). Taylor & Francis. https://doi.org/10.1201/9780203946282
Triatmodjo, B. (2008). Hidrologi Terapan (Cet. 1). Beta Offset, Yogyakarta. ISBN: 978-979-8541-40-7
Verma, S., & Verma, R.K. (2023). SCS-CN methodology further modified. Water Supply, 23(6), 2604–2622. https://doi.org/10.2166/ws.2023.129
Zhao, B., Xin, T., Li, P., Ma, F., Gao, B., & Fan, R. (2023). Regulation of flood dynamics by a check dam system in a typical ecological construction watershed on the Loess Plateau, China. Water, 15(11), 2000. https://doi.org/10.3390/w15112000
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