Flood modeling in Samsun Engiz Stream: Evaluation of the adequacy of river sections with HEC-RAS

Abstract

Floods pose a significant threat to communities, particularly in Turkey's Central Black Sea Region, where they cause widespread economic, social, and environmental damage. The Ondokuzmayis district of Samsun has been especially vulnerable to recurrent flooding, emphasizing the need for precise risk assessments and effective flood management strategies. In this study, the flood modelling of Engiz Stream, located in the Ondokuzmayis district of Samsun, was conducted using one-dimensional modeling due to its speed, low computational cost and ease of implementation. Hydraulic modeling was performed in HEC-RAS using flow data from Ballıca Station on Engiz Stream and statistical distributions from the EasyFit software library. In the study, flow rates for 25, 50, 100, and 500-year flood return periods (Q25: 431 m³/s, Q50: 479.87 m³/s, Q100: 531.75 m³/s, Q500: 665.37 m³/s) were calculated, and the flow was modeled using a 5-meter resolution digital surface model. The modeling results indicated that while the cross-sections in urban areas were adequate, the river cross-sections in the agricultural areas where the river flows into the Black Sea were insufficient for the Q25 flow rate and beyond.

Keywords

• Samsun
• Engiz Stream
• Flood Modeling
• HEC-RAS

References

1. Bozdoğan, M., & Canpolat, E. (2024). Calculation of flood recurrence and modeling with HEC-RAS in Delibekirli Basin (Kırıkhan/Hatay). Journal of Natural Disasters and Environment, 10, 478–503. https://doi.org/10.21324/dacd.1387971
2. Çitgez, T. (2011). A research on the prevention of torrent and flood damages: A case study on Düzce-Kaynaşlı (Publication No. 565007) [Master’s Thesis, Düzce University], YÖK National Thesis Center.
3. Demir, V. (2020). Determination of flood areas using one- and two-dimensional models in the Samsun Mert Basin (Publication No: 654578) [Doctoral Thesis, Ondokuz Mayıs University]. YÖK National Thesis Center.
4. Demir, V., & Keskin, A. Ü. (2019). Determination of roughness coefficient using Cowan’s method and remote sensing. Gazi Journal of Engineering Sciences, 5, 167–177. https://doi.org/10.30855/gmbd.2019.02.06
5. Demir, V., & Keskin, A. Ü. (2021). Hydraulic model calibration in flood modeling (Samsun, Mert River example). Proceedings Book of 5th International 19 May Innovative Scientific Approaches Congress, Samsun, Türkiye, 428–433.
6. Demir, V., & Kisi, O. (2016). Flood hazard mapping by using geographic information system and hydraulic model: Mert River, Samsun, Turkey. Advances in Meteorology, 2016, 4891015. https://doi.org/10.1155/2016/4891015
7. Demir, V., Beden, N., & Ülke, A. (2021). Review and comparison of flood modeling methods. European Journal of Science and Technology, 2021, 1013–1021. https://doi.org/10.31590/ejosat.1010220
8. Doğu, A. (2016). Calculation of flood discharges and one-dimensional modeling of the Kırıkkale Çoruhözü Stream (Publication No. 457412) [Master’s Thesis, Kırıkkale University]. YÖK National Thesis Center.

9. Doğu, A., & Yıldız, O. (2019). One-dimensional flood flow modeling in the Kırıkkale Çoruhözü Stream. International Journal of Engineering Research and Development, 11, 748–758. https://doi.org/10.29137/umagd.567086
10. Eryürük, K., & Eryürük, Ş. (2024). Assessing trends in monthly precipitation and relative Humidity: An analysis for climate change reference in Konya. Necmettin Erbakan University Journal of Science and Engineering, 6(1), 105-114. https://doi.org/10.47112/neufmbd.2024.35
11. Farooq, M., Shafique, M., & Khattak, M. S. (2018). Flood frequency analysis of river Swat using Log Pearson type 3, Generalized Extreme Value, Normal, and Gumbel Max distribution methods. Arabian Journal of Geosciences, 11, 216. https://doi.org/10.1007/s12517-018-3553-z
12. General Directorate of Mapping. (2024). Digital Surface Model 5m Level-0 (DSM5-L0). Retrieved 20 September, 2024, from https://www.harita.gov.tr/urun/sayisal-yuzey-modeli-5-m-seviye-0-sym5-l0-/1
13. General Directorate of State Hydraulic Works-DSI. (2024). Flow Observation Yearbooks, Activities. Retrieved 20 September, 2024, from https://www.dsi.gov.tr/Sayfa/Detay/744
14. Geyikli, M. S. (2015). Determination of flood risk maps using GIS software (Publication No. 424346) [Master’s Thesis, İnönü University], YÖK National Thesis Center.
15. Ministry of Agriculture and Forestry. (2015). Yeşilırmak Basin Flood Management Plan. Ankara, Türkiye. Retrieved 20 September, 2024, from https://www.tarimorman.gov.tr/SYGM/Belgeler/Ta%C5%9Fk%C4%B1n%20Y%C3%B6netim%20Planlar%C4%B1/1)%20YESILIRMAK%20HAVZASI%20TA%C5%9EKIN%20Y%C3%96NETIM%20PLANI.pdf%20YESILIRMAK%20HAVZASI%20TA%C5%9EKIN%20Y%C3%96NETIM%20PLANI.pdf
16. Peker, İ. B., Gülbaz, S., Demir, V., Orhan, O., & Beden, N. (2024). Integration of HEC-RAS and HEC-HMS with GIS in flood modeling and flood hazard mapping. Sustainability, 16(3), https://doi.org/10.3390/su16031226
17. Tektaş, Y., & Polat, N. (2021). Flood modeling with HEC-RAS and flood damage analysis from Sentinel-2 remote sensing image: Example of Çakmak Creek (Çınar Region) in Diyarbakır. Turkish Journal of Remote Sensing, 3(1), 28–35. https://doi.org/10.51489/tuzal.924926
18. Uçar, İ. (2010). Flood analysis of Trabzon Değirmendere basin using geographic information systems and a hydraulic model (Publication No. 269719) [Master’s Thesis, Gazi University], YÖK National Thesis Center.
19. USACE. (2023). HEC-RAS River Analysis System Hydraulic Reference Manual Version 5.0. Hydrologic Engineering Center. Retrieved 29 December, 2024, from https://www.hec.usace.army.mil/software/hec-ras/documentation/HEC-RAS%205.0%20Reference%20Manual.pdf
20. USACE. (2024). HEC-RAS, 1D Saint-Venant Equations. USACE Hydrologic Engineering Center. Retrieved 20 June, 2024, from https://www.hec.usace.army.mil/confluence/rasdocs/rasmuddebris/non-newtonian-technical-reference-manual/non-newtonian-flow-equations/1d-saint-venant-equations
21. USGS. (2010). HEC-RAS River Analysis System, User’s Manual, Version 4.1. Retrieved 20 September, 2024, from https://www.hec.usace.army.mil/software/hec-hms/documentation/HEC-HMS_Users_Manual_4.1.pdf
22. Yiğit, A. Y., & Kaya, Y. (2020). Investigation of flood areas by using Sentinel-2A satellite data: A case study of Düzce. Turkish Journal of Remote Sensing, 2(1), 1–9.