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Hydraulic Modeling and Flood Mapping of Flood Plain Along Megech River, Upper Blue Nile Basin, Ethiopia

Published in Hydrology (Volume 13, Issue 4)
Received: 13 October 2025     Accepted: 6 November 2025     Published: 9 December 2025
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Abstract

Every year, devastating floods occur in numerous places around the world. Floods are also a daily occurrence in Ethiopia, wreaking havoc and claiming lives, especially in low lying areas such as cities. The Dembia floodplain is one of the most flood-prone districts in Ethiopia. Most victims of flood disasters are people who live in rural areas and make their living from agriculture and livestock near a floodplain. Due to the flooding on the Megech River in Ethiopia, the focus of the study was on hydraulic modeling and flood mapping. Combining the technologies HEC-HMS, HEC-GeoHMS, HEC-RAS and ArcGIS to create a regional model for floodplain identification and representation resulted in floodplain mapping. Using daily time series data, the hydrologic model HEC-HMS was calibrated for return periods of 2, 10, 25, 50, and 100 years. The model HEC-HMS provides 139.7 m3s-1, 228.2 m3s-1, 369.7 m3s-1, 437.8 m3s-1, and 568.8 m3s-1 for return periods of 2, 10, 25, 50, and 100, respectively. A one-dimensional hydraulic model, HEC-RAS, with the HEC-GeoRAS tool extension in ArcGIS was used for flood mapping. The inundation mapping results in 19.92 km2, 23.76 km2, 25.32 km2, 28.65 km2, and 30.09 km2 of inundation area for return periods of 2, 10, 25, 50, and 100, respectively. According to the study, floods have significant impacts as they inundate agricultural and pastoral lands, which has a direct negative impact on of the society. Moreover, flood hazards were evaluated based on the return period and water depth. Therefore, central and local governments should introduce appropriate policies and measures to address this problem.

Published in Hydrology (Volume 13, Issue 4)
DOI 10.11648/j.hyd.20251304.12
Page(s) 224-233
Creative Commons

This is an Open Access article, distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution and reproduction in any medium or format, provided the original work is properly cited.

Copyright

Copyright © The Author(s), 2025. Published by Science Publishing Group

Keywords

Flood Mapping, HEC-HMS, Flood Damage, HEC-RAS, Flood Inundation

References
[1] Brunner, G. W. (2016) HEC-RAS River Analysis System Hydraulic Reference Manual, Hydrologic Engineering Center.
[2] A. Halefom, E. Sisay, D. Khare, T. Worku, M. Dananto, and K. Narayanan, “Precipitation and Runoff Modelling in Megech Watershed, Tana Basin, Amhara Region of Ethiopia,” Am. J. Environ. Eng., vol. 8, no. 3, pp. 45–53, 2018,
[3] Desalegn, H. and Mulu, A. (2021) ‘Mapping flood inundation areas using GIS and HECRAS model at Fetam River, Upper Abbay Basin, Ethiopia’, Scientific African, 12, p. e00834.
[4] El-Naqa, A. and Jaber, M. (2018) ‘Floodplain Analysis using ArcGIS, HEC-GeoRAS and HEC-RAS in Attarat Um Al-Ghudran Oil Shale Concession Area, Jordan’, Journal of Civil Environmental Engineering, 08 (05).
[5] ENTRO, “Final Report Flood Risk Mapping Consultancy for Pilot Areas in Ethiopia A report of Riverside Technology, inc. to the Eastern Nile Technical Regional Office,” no. July, 2010.
[6] Goswami, G., Prasad, R. K., and Kumar, D. (2022) ‘Hydrodynamic flood modeling of Dikrong River in Arunachal Pradesh, India: a simplified approach using HEC-RAS 6.1’, Modeling Earth Systems and Environment Preprint], (2003).
[7] Hagos, Y. G. et al. (2022) ‘Flood hazard assessment and mapping using GIS integrated with multi-criteria decision analysis in upper Awash River basin, Ethiopia’, Applied Water Science, 12 (7), pp. 1–18.
[8] Hamdan, A. N. A., Almuktar, S., and Scholz, M. (2021) ‘Rainfall-Runoff Modeling Using the HEC-HMS Model for the’, Hydrology, 8(58). Available at:
[9] James I. J. I Awu; C. C. Mbajiorgu; H. I. Manta and D. D. (2017) ‘Flood Inundation Simulation using HEC-RAS Hydrologic Model: A Case Study of Oyun River, Nigeria’.
[10] Namara, W. G., Damisse, T. A., and Tufa, F. G. (2022) ‘Application of HEC-RAS and HECGeoRAS model for Flood Inundation Mapping, the case of Awash Bello Flood Plain, Upper Awash River Basin, Oromiya Regional State, Ethiopia’, Modeling Earth Systems and Environment, 8 (2), pp. 1449–1460.
[11] Natarajan, S., and Radhakrishnan, N. (2019) ‘Simulation of extreme event-based rainfall–runoff process of an urban catchment area using HEC-HMS’, Modeling Earth Systems and Environment, 5 (4), pp. 1867–1881.
[12] Patel, D. P., et al. (2017) ‘Assessment of flood inundation mapping of Surat city by coupled 1D/2D hydrodynamic modeling: a case application of the new HEC-RAS 5’, Natural Hazards, 89 (1), pp. 93–130.
[13] Ramly, S., and Tahir, W. (2016) ‘Isfram 2015’, Isfram 2015 Preprint].
[14] Roy, D., et al. (2013) ‘Calibration and validation of HEC-HMS model for a river basin in eastern India’, ARPN Journal of Engineering and Applied Sciences, 8(1), pp. 40–56.
[15] Shakarneh, M. O. A., et al. (2022) ‘Modeling of rainfall–runoff events using HEC-HMS model in southern catchments of Jerusalem Desert-Palestine’, Arabian Journal of Geosciences, 15 (1).
[16] Yamazaki, D., et al. (2011) ‘A physically based description of floodplain inundation dynamics in a global river routing model’, Water Resources Research, 47(4), pp. 1–21.
[17] S. Fikadu and Y. Michael, “By: Solomon Fikadu,” 2020, unpublished.
[18] K. Vashist and K. K. Singh, “HEC-RAS 2D modeling for flood inundation mapping: a case study of the Krishna River Basin,” vol. 18, no. 4, pp. 831–844, 2023.
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  • APA Style

    Demamu, M. T. (2025). Hydraulic Modeling and Flood Mapping of Flood Plain Along Megech River, Upper Blue Nile Basin, Ethiopia. Hydrology, 13(4), 224-233. https://doi.org/10.11648/j.hyd.20251304.12

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    ACS Style

    Demamu, M. T. Hydraulic Modeling and Flood Mapping of Flood Plain Along Megech River, Upper Blue Nile Basin, Ethiopia. Hydrology. 2025, 13(4), 224-233. doi: 10.11648/j.hyd.20251304.12

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    AMA Style

    Demamu MT. Hydraulic Modeling and Flood Mapping of Flood Plain Along Megech River, Upper Blue Nile Basin, Ethiopia. Hydrology. 2025;13(4):224-233. doi: 10.11648/j.hyd.20251304.12

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  • @article{10.11648/j.hyd.20251304.12,
      author = {Masresha Tenaw Demamu},
      title = {Hydraulic Modeling and Flood Mapping of Flood Plain Along Megech River, Upper Blue Nile Basin, Ethiopia},
      journal = {Hydrology},
      volume = {13},
      number = {4},
      pages = {224-233},
      doi = {10.11648/j.hyd.20251304.12},
      url = {https://doi.org/10.11648/j.hyd.20251304.12},
      eprint = {https://article.sciencepublishinggroup.com/pdf/10.11648.j.hyd.20251304.12},
      abstract = {Every year, devastating floods occur in numerous places around the world. Floods are also a daily occurrence in Ethiopia, wreaking havoc and claiming lives, especially in low lying areas such as cities. The Dembia floodplain is one of the most flood-prone districts in Ethiopia. Most victims of flood disasters are people who live in rural areas and make their living from agriculture and livestock near a floodplain. Due to the flooding on the Megech River in Ethiopia, the focus of the study was on hydraulic modeling and flood mapping. Combining the technologies HEC-HMS, HEC-GeoHMS, HEC-RAS and ArcGIS to create a regional model for floodplain identification and representation resulted in floodplain mapping. Using daily time series data, the hydrologic model HEC-HMS was calibrated for return periods of 2, 10, 25, 50, and 100 years. The model HEC-HMS provides 139.7 m3s-1, 228.2 m3s-1, 369.7 m3s-1, 437.8 m3s-1, and 568.8 m3s-1 for return periods of 2, 10, 25, 50, and 100, respectively. A one-dimensional hydraulic model, HEC-RAS, with the HEC-GeoRAS tool extension in ArcGIS was used for flood mapping. The inundation mapping results in 19.92 km2, 23.76 km2, 25.32 km2, 28.65 km2, and 30.09 km2 of inundation area for return periods of 2, 10, 25, 50, and 100, respectively. According to the study, floods have significant impacts as they inundate agricultural and pastoral lands, which has a direct negative impact on of the society. Moreover, flood hazards were evaluated based on the return period and water depth. Therefore, central and local governments should introduce appropriate policies and measures to address this problem.},
     year = {2025}
    }
    

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  • TY  - JOUR
    T1  - Hydraulic Modeling and Flood Mapping of Flood Plain Along Megech River, Upper Blue Nile Basin, Ethiopia
    AU  - Masresha Tenaw Demamu
    Y1  - 2025/12/09
    PY  - 2025
    N1  - https://doi.org/10.11648/j.hyd.20251304.12
    DO  - 10.11648/j.hyd.20251304.12
    T2  - Hydrology
    JF  - Hydrology
    JO  - Hydrology
    SP  - 224
    EP  - 233
    PB  - Science Publishing Group
    SN  - 2330-7617
    UR  - https://doi.org/10.11648/j.hyd.20251304.12
    AB  - Every year, devastating floods occur in numerous places around the world. Floods are also a daily occurrence in Ethiopia, wreaking havoc and claiming lives, especially in low lying areas such as cities. The Dembia floodplain is one of the most flood-prone districts in Ethiopia. Most victims of flood disasters are people who live in rural areas and make their living from agriculture and livestock near a floodplain. Due to the flooding on the Megech River in Ethiopia, the focus of the study was on hydraulic modeling and flood mapping. Combining the technologies HEC-HMS, HEC-GeoHMS, HEC-RAS and ArcGIS to create a regional model for floodplain identification and representation resulted in floodplain mapping. Using daily time series data, the hydrologic model HEC-HMS was calibrated for return periods of 2, 10, 25, 50, and 100 years. The model HEC-HMS provides 139.7 m3s-1, 228.2 m3s-1, 369.7 m3s-1, 437.8 m3s-1, and 568.8 m3s-1 for return periods of 2, 10, 25, 50, and 100, respectively. A one-dimensional hydraulic model, HEC-RAS, with the HEC-GeoRAS tool extension in ArcGIS was used for flood mapping. The inundation mapping results in 19.92 km2, 23.76 km2, 25.32 km2, 28.65 km2, and 30.09 km2 of inundation area for return periods of 2, 10, 25, 50, and 100, respectively. According to the study, floods have significant impacts as they inundate agricultural and pastoral lands, which has a direct negative impact on of the society. Moreover, flood hazards were evaluated based on the return period and water depth. Therefore, central and local governments should introduce appropriate policies and measures to address this problem.
    VL  - 13
    IS  - 4
    ER  - 

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