Dam Break Analysis Using HEC-RAS Software for Oyan River Dam Abeokuta, Nigeria

Authors

  • A. A. Olanipekun Department of Civil and Environmental Engineering, Bells University of Technology, Ota, Nigeria.
  • O. O. Olofintoye Department of Water Resourses and Enivironmental Engineering, Uiversity of Ilorin, Nigeria. https://orcid.org/0000-0002-6111-8032
  • O. J. Badmus Department of Water Resourses and Enivironmental Engineering, Uiversity of Ilorin, Nigeria. https://orcid.org/0009-0000-5249-0433
  • D. U. Idusuyi Department of Civil and Environmental Engineering, Bells University of Technology, Ota, Nigeria. https://orcid.org/0000-0002-6913-3325
  • F. Alao Department of Civil and Environmental Engineering, Bells University of Technology, Ota, Nigeria.
  • O. Bayode Department of Civil and Environmental Engineering, Bells University of Technology, Ota, Nigeria. https://orcid.org/0009-0005-1701-1413
  • J. I. Braimah Department of Civil and Environmental Engineering, Bells University of Technology, Ota, Nigeria. https://orcid.org/0009-0000-3778-3641
  • O. O. Aiyelokun Department of Civil Engineering, University of Ibadan, Ibadan, Nigeria.
  • A. A. Opebiyi

DOI:

https://doi.org/10.63746/njtd.v23i1.3861

Keywords:

Oyan river dam, HEC-RAS, Dam breach characteristics, Peak discharge, Inundation depth

Abstract

This study presents a thorough dam break analysis of Oyan Dam, Nigeria, using the Hydrologic Engineering Center-River Analysis System (HEC-RAS) 6.6 software. The analysis simulated two hypothetical failure scenarios: overtopping and piping, to evaluate hydraulic and flood risks associated with potential failure of the dam. Breach characteristics were calculated using Froehlich’s analytical formulas, and unsteady flow simulations were conducted for an 11 km downstream reach. Key hydraulic parameters, including peak discharge, stage elevation, flow velocity and flood wave travel time, were computed. Results revealed that the overtopping scenario produced a higher peak discharge of 22,556.47 m³/s at the dam and greater flood velocities of about 10.24 m/s, whereas the piping failure produced a lower peak discharge of 17,140.02m³/s. In both scenarios, flood wave propagation was characterized by deeper inundation near the dam and progressively reduced flood depths downstream. Floodplain mapping using HEC-RAS Mapper revealed extensive inundation of downstream areas, including critical infrastructure, settlements and natural reserves. Simulations indicated that overtopping poses an immediate and severe flood hazard, making it the critical failure mode. Evaluation of possible downstream flood hazards identified at-risk areas: Arakanga nature reserve, Awyan, Iwofin and potential flooding of Lagos State through the Ogun River tributary system. This study highlights the critical importance of implementing flood risk reduction measures, construction of levees, development of auxiliary retention dams, emergency evacuation planning and enhanced dam monitoring systems. This analysis should improve dam safety, disaster preparedness and regional flood management planning, especially for coastal communities like Oyan and communities downstream of the dam.

References

Adewumi, J. R., Adebayo, A. O., & Salami, A. W. (2016). Flood hazard mapping and risk assessment in Nigeria using hydraulic modelling techniques. Journal of Flood Risk Management, 9(4), 333–345. https://doi.org/10.1111/jfr3.12162

Ackerman, C.T., & Brunner, G.W. (2006). Dam failure analysis using HEC-RAS and HEC-GeoRAS, Conference volume of “Third Federal Interagency Hydrologic Modeling Conference”, April 2–6, Reno, Nevada, USA.

Ayeni A & Ojifo L (2018). The socio-economics dynamics of Dam on Rural Communities: A case study of Oyan Dam, Nigeria. Proc. IAHS, 379, 175–180, 2018 https://doi.org/10.5194/piahs-379-175-2018

Balogun, O. S., & Ganiyu, H. O. (2017). Study and analysis of Asa River hypothetical dam break using HEC-RAS. Nigerian Journal of Technology, 36(1), 315–321.http://dx.doi.org/10.4314/njt.v36i1.39

Bhattarai, S., Zhou, Y., Zhao, C., & Yadav, R. (2016). An overview on types, construction method, failure and key technical issues during construction of high dams. Electronic Journal of Geotechnical Engineering, 21(26), 10415-10432. Available at ejge.com.

Brunner, G (2014). Using HEC-RAS for dam break studies, TD-39, Us Army Corps Eng. Hydrologic Engineering Center 74. http://www.hec.usace.army.mil/

Dalu, T., Wasserman, R. J., & Magoro, M. L. (2018). Flood risk assessment and dam-break analysis using hydraulic modelling in Southern Africa. Natural Hazards, 94(2), 789–808. https://doi.org/10.1007/s11069-018-3417-9

De Wrachien, D. (2009). Dam-break problems, solutions and case studies. WIT press.

El Gayar, A. (2020). Impact assessment on water harvesting and valley dams. Int. J. Agric. Inven, 5, 266–282. https://doi.org/10.46492/IJAI./2020.5.2.19

Eruola, A. O. (2017). Hydrometeorological Network Upgrade Design for Ogun-Oshun River Basin. Journal of Agricultural Science and Environment, 17(1), 103–113https://doi.org/10.51406/jagse.v17i1.1795

Froehlich D. (2008). Embankment dam breach parameters and their uncertainties, Journal of Hydraulic Engineering, 134, 1708-1720. https://doi.org/10.1061/(ASCE)0733-9429(2008)134:12(1708)

Hager, W. H., Schleiss, A. J., Boes, R. M., & Pfister, M. (2022). Hydraulic engineering of dams. CRC Press.

HEC-RAS User’s Manual, U.S. Army Corps of Engineers. (2021).http://www.hec.usace.army.mil/

ICOLD. (2018). Jcold.or.Jp. https://jcold.or.jp/cm/wp-content/uploads/2018/02/ICOLD_2018_Final_Bulletin.pdf

Kebede, G., Tadesse, H., & Alemayehu, T. (2020). Dam breach analysis and downstream flood propagation: KesemKebena Dam, Ethiopia. Open Journal of Modern Hydrology, 9, 113–142. https://doi.org/10.4236/ojmh.2019.94007

Kiwanuka, M., Chelangat, C., Mubialiwo, A., Lay, F. J., Mugisha, A., Mbujje, W. J., & Mutanda, H. E. (2023). Dam breach analysis of Kibimba Dam in Uganda using HEC-RAS and HEC-GeoRAS. Environmental Systems Research, 12(1), 31.https://doi.org/10.1186/s40068-023-00317-4

Lawal, M. O., Adeyemo, J. A., & Jimoh, O. D. (2022). Assessment of potential dam-break flooding using HEC-RAS: A Nigerian case study. Journal of Water and Climate Change, 13(3), 1031–1046. https://doi.org/10.2166/wcc.2021.221

Loucks, D.P., & van Beek, E. (2017). Water Resources Planning and Management: An Overview. In: Water Resource Systems Planning and Management. Springer, Cham. https://doi.org/10.1007/978-3-319-44234-1_1

Mekonnen, M., Berhanu, D., & Fekadu, B. (2018). Dam breach analysis and flood inundation mapping: Gidabo Dam, Ethiopia (Master’s thesis, Addis Ababa University).

Mohamed, M. J., Karim, I. R., Fattah, M. Y., & Al Ansari, N. (2023). Modelling flood wave propagation as a result of dam piping failure using 2D HEC RAS. Civil Engineering Journal (Iran), 9(10), 2503–2515. https://doi.org/10.28991/CEJ 2023 09 10 010

Mulatu, D. W., Assen, M., & Legesse, D. (2021). Dam-break flood hazard mapping using HEC-RAS and GIS: A case study in Ethiopia. Modeling Earth Systems and Environment, 7, 1509–1523. https://doi.org/10.1007/s40808-020-00961-2

NiMet (2025). Gov.Ng. https://www.nimet.gov.ng/

Ouammi, A., Ettouhami, A., & Bahir, M. (2020). Flood hazard assessment using hydraulic modelling and GIS in North Africa. Arabian Journal of Geosciences, 13(9), 1–15. https://doi.org/10.1007/s12517-020-05376-9

Oyeleke, O. O., & Olatunji, S. O. (2019). Dam-break analysis and flood inundation mapping using HEC-RAS: A case study of Eleyele Dam, Nigeria. International Journal of Engineering Research and Technology, 8(6), 227–234.

Okeola, O., & Adeleke, A. K. (2022). Dam Break Analysis Using HEC-RAS. Journal of Agricultural Engineering and Technology(JAET), 2.

OpenTopography. (2013). Shuttle Radar Topography

Mission (SRTM) Global. OpenTopography. https://doi.org/10.5069/G9445JDF

Sharma, P. (2016). Dam break analysis using HEC-RAS and HEC-GeoRAS – A case study of Ajwa reservoir. Journal of Water Resources and Ocean Science, 5(6), 108. https://doi.org/10.11648/j.wros.20160506.15

Singh, V. P. (2013). Dam breach modeling technology (Vol. 17). Springer Science & Business Media.

Wang, Y., Fu, Z., Cheng, Z., Xiang, Y., Chen, J., Zhang, P., & Yang, X. (2024). Uncertainty analysis of dam-break flood risk consequences under the influence of non-structural measures. International Journal of Disaster Risk Reduction: IJDRR, 102(104265), 104265. https://doi.org/10.1016/j.ijdrr.2024.104265

Xiong, Y. (2011). A dam break analysis using HEC-RAS, Journal of Water Resource and Protection, 3, 370-37910.4236/jwarp.2011.36047

Zhao, K., Zhong, Q., Chen, S., Wu, H., Shan, Y., Qian, B., Jing, P., & Chao, Y. (2024). Experimental study on overtopping failure of concrete face rockfill dam. Case Studies in Construction Materials, 21(e03640), e03640. https://doi.org/10.1016/j.cscm.2024.e03640

Downloads

Published

2026-03-31

Issue

Vol. 23 No. 1 (2026): Volume 23, Issue 1, March 2026.

Section

Articles

License

Copyright (c) 2026 Nigerian Journal of Technological Development

Creative Commons License

This work is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License.

In accordance with the Copyright Act of 1976, which became effective January 1, 1978, the following statement signed by each author must accompany the manuscript submitted: "I, the undersigned author, transfer all copyright ownership of the manuscript referenced above to the Nigerian Journal of Technological Development, in the event the work is published. I warrant that the article is original, does not infringe upon any copyright or other proprietary right of any third party, is not under consideration by another journal, and has not been published previously. I have reviewed and approved the submitted version of the manuscript and agree to its publication in the Nigerian Journal of Technological Development." A copyright transfer form can be downloaded from the NJTD Website (http://njtd.com.ng/index.php/njtd). Author(s) will be consulted, whenever possible, regarding republication of material. All authors must have access to the data presented, and the authors and sponsor (if applicable) must agree to share original data with the editor if requested.