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Flood Inundation Mapping of Jigjiga-Town and Its Surrounding Environment: Using GIS & HEC-RAS Model

Received: 15 February 2021    Accepted: 24 March 2021    Published: 20 April 2021
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Abstract

Flood is one of the natural hazards that have negative impacts on peoples and property. It occurs in lowland areas without any sign when excessive rains fall in adjacent highland areas. Since flood is unavoidable natural phenomena, adopting protective mechanisms are crucial. This study was conducted in Jigjiga town, Eastern Ethiopia with main objective of delineating flood risk areas. For the purpose of flood risk mapping preparation, hydrology and hydraulics models have been used. Besides, land use /cover change detection analysis has been carried out between the year 2003 and 2017. Soil Conservation System (SCS) Curve Number method was used as hydrology model. Satellite and field data have been collected, filtered and finally a geo-database has been developed in GIS environment. Flow data and river geometry data, which obtained from hydrology model and prepared using HEC-GeoRAS was used as inputs for HEC-RAS model. Before running steady flow analysis, correction of geometry data has been carried out in HEC-RAS environment. From the study, it was found that, expansion of built up area and agricultural land at the cost of open area. Flood inundation extent maps show that increasing in aerial coverage as return period increases but the variation in area between consecutive periods are small. The flood extent obtained by applying structural flood control mechanism shows that the measure reduces the flood extent considerably but it also exhibits some part of the town is still in undated in all return periods. From the analysis it was observed that the increases in built up area and agricultural land may lead to increase flooding. Besides, among the LULC classes fall under high risk zone at different return periods, built up area and agricultural land consist a considerable proportion. It also observed that, flood risk areas increase as return period increases but the variation between the periods is small. The flood risk map can be used for planning control measures for future flood.

Published in International Journal of Environmental Protection and Policy (Volume 9, Issue 2)
DOI 10.11648/j.ijepp.20210902.14
Page(s) 40-49
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), 2024. Published by Science Publishing Group

Keywords

Flood Mapping, GIS, HEC-GeoRAS, HEC-RAS, Soil Curve Number

References
[1] World Meteorological Organization (1990). International Meteorological Vocabulary, WMO- NO: 182, draft second edition, Geneva, Switzerland.
[2] Sisir, P., & K. Balan (2014). Flood risk mapping of Kadalundi river basin using GIS. International Journal of Scientific & Engineering Research, 5 (7).
[3] Smith, K. (2001). Environmental hazards assessing risk and reducing disaster (3rd Ed.). Rutledge 11, New Fetter Lane: London.
[4] Bronstert, A. (2003). Floods and climate change: interactions and impacts. Risk Analysis, 23, 545–557.
[5] Hapuarachchi, H. A. P., Wang, Q. J., & Pagano, T. C. (2011). A review of advances in flash flood forecasting. Hydro. Process, 25, 2771–2784.
[6] Olivera, F., & Midment, D. (1999). System of GIS based hydrological and hydraulic application for highway engineering: Summary Report. Austin: University of Texas.
[7] Hydrologic Engineering Center (2013). HEC-RAS Manual. California: U.S. Army Corps of Engineers Hydrologic Engineering Center.
[8] Ouma, Y., & Tateishi, R. (2014). Urban flood vulnerability and risk mapping using integrated multi-parametric AHP and GIS: methodological overview and case study assessment. Water, 6 (6), 1515-1545
[9] Weldegebriel M., Habtamu A., and Barana B. (2016). Dynamics of land use land cover chande and urbanization in Jigjiga town, Ethiopia. Somali regional state, eastern Ethiopia
[10] Fikre Z. and Abdurhman M. (2019). Land use land cover dynamics of eastern pastoral ranglands of Somali region, Ethiopia
[11] Central Statistical Agency (2013). Population projections for Ethiopia 2007-2037. Addis Ababa, Ethiopia: Author.
[12] Christian, W., 2007. Hand-book on statistical distributions for experimentalists. University of Stockholm: Particle Physics Group Fysikum.
[13] Hydrologic Engineering Center (2013). HEC-GeoHMS Technical Reference Manual. California: U.S. Army Corps of Engineers Hydrologic Engineering Center.
[14] United States Department of Agriculture, Natural Resources Conservation (1987). Urban Hydrology for Small watersheds. Technical Release 55.
[15] Hydrologic Engineering Center (2013). HEC-GeoRAS Technical Reference Manual. California: U.S. Army Corps of Engineers Hydrologic Engineering Center.
[16] United Nation Environmental Protection (2002). State of the environment and policy retrospective
[17] O’Connell E., John E., Greg O’D., and Paul Q. (2007). Is there a link between agricultural land use management and flooding?
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  • APA Style

    Abirham Cherinet, Sadnur Worku. (2021). Flood Inundation Mapping of Jigjiga-Town and Its Surrounding Environment: Using GIS & HEC-RAS Model. International Journal of Environmental Protection and Policy, 9(2), 40-49. https://doi.org/10.11648/j.ijepp.20210902.14

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    ACS Style

    Abirham Cherinet; Sadnur Worku. Flood Inundation Mapping of Jigjiga-Town and Its Surrounding Environment: Using GIS & HEC-RAS Model. Int. J. Environ. Prot. Policy 2021, 9(2), 40-49. doi: 10.11648/j.ijepp.20210902.14

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    AMA Style

    Abirham Cherinet, Sadnur Worku. Flood Inundation Mapping of Jigjiga-Town and Its Surrounding Environment: Using GIS & HEC-RAS Model. Int J Environ Prot Policy. 2021;9(2):40-49. doi: 10.11648/j.ijepp.20210902.14

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  • @article{10.11648/j.ijepp.20210902.14,
      author = {Abirham Cherinet and Sadnur Worku},
      title = {Flood Inundation Mapping of Jigjiga-Town and Its Surrounding Environment: Using GIS & HEC-RAS Model},
      journal = {International Journal of Environmental Protection and Policy},
      volume = {9},
      number = {2},
      pages = {40-49},
      doi = {10.11648/j.ijepp.20210902.14},
      url = {https://doi.org/10.11648/j.ijepp.20210902.14},
      eprint = {https://article.sciencepublishinggroup.com/pdf/10.11648.j.ijepp.20210902.14},
      abstract = {Flood is one of the natural hazards that have negative impacts on peoples and property. It occurs in lowland areas without any sign when excessive rains fall in adjacent highland areas. Since flood is unavoidable natural phenomena, adopting protective mechanisms are crucial. This study was conducted in Jigjiga town, Eastern Ethiopia with main objective of delineating flood risk areas. For the purpose of flood risk mapping preparation, hydrology and hydraulics models have been used. Besides, land use /cover change detection analysis has been carried out between the year 2003 and 2017. Soil Conservation System (SCS) Curve Number method was used as hydrology model. Satellite and field data have been collected, filtered and finally a geo-database has been developed in GIS environment. Flow data and river geometry data, which obtained from hydrology model and prepared using HEC-GeoRAS was used as inputs for HEC-RAS model. Before running steady flow analysis, correction of geometry data has been carried out in HEC-RAS environment. From the study, it was found that, expansion of built up area and agricultural land at the cost of open area. Flood inundation extent maps show that increasing in aerial coverage as return period increases but the variation in area between consecutive periods are small. The flood extent obtained by applying structural flood control mechanism shows that the measure reduces the flood extent considerably but it also exhibits some part of the town is still in undated in all return periods. From the analysis it was observed that the increases in built up area and agricultural land may lead to increase flooding. Besides, among the LULC classes fall under high risk zone at different return periods, built up area and agricultural land consist a considerable proportion. It also observed that, flood risk areas increase as return period increases but the variation between the periods is small. The flood risk map can be used for planning control measures for future flood.},
     year = {2021}
    }
    

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  • TY  - JOUR
    T1  - Flood Inundation Mapping of Jigjiga-Town and Its Surrounding Environment: Using GIS & HEC-RAS Model
    AU  - Abirham Cherinet
    AU  - Sadnur Worku
    Y1  - 2021/04/20
    PY  - 2021
    N1  - https://doi.org/10.11648/j.ijepp.20210902.14
    DO  - 10.11648/j.ijepp.20210902.14
    T2  - International Journal of Environmental Protection and Policy
    JF  - International Journal of Environmental Protection and Policy
    JO  - International Journal of Environmental Protection and Policy
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    EP  - 49
    PB  - Science Publishing Group
    SN  - 2330-7536
    UR  - https://doi.org/10.11648/j.ijepp.20210902.14
    AB  - Flood is one of the natural hazards that have negative impacts on peoples and property. It occurs in lowland areas without any sign when excessive rains fall in adjacent highland areas. Since flood is unavoidable natural phenomena, adopting protective mechanisms are crucial. This study was conducted in Jigjiga town, Eastern Ethiopia with main objective of delineating flood risk areas. For the purpose of flood risk mapping preparation, hydrology and hydraulics models have been used. Besides, land use /cover change detection analysis has been carried out between the year 2003 and 2017. Soil Conservation System (SCS) Curve Number method was used as hydrology model. Satellite and field data have been collected, filtered and finally a geo-database has been developed in GIS environment. Flow data and river geometry data, which obtained from hydrology model and prepared using HEC-GeoRAS was used as inputs for HEC-RAS model. Before running steady flow analysis, correction of geometry data has been carried out in HEC-RAS environment. From the study, it was found that, expansion of built up area and agricultural land at the cost of open area. Flood inundation extent maps show that increasing in aerial coverage as return period increases but the variation in area between consecutive periods are small. The flood extent obtained by applying structural flood control mechanism shows that the measure reduces the flood extent considerably but it also exhibits some part of the town is still in undated in all return periods. From the analysis it was observed that the increases in built up area and agricultural land may lead to increase flooding. Besides, among the LULC classes fall under high risk zone at different return periods, built up area and agricultural land consist a considerable proportion. It also observed that, flood risk areas increase as return period increases but the variation between the periods is small. The flood risk map can be used for planning control measures for future flood.
    VL  - 9
    IS  - 2
    ER  - 

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Author Information
  • Climate Science Research Department, Ethiopian Environment and Forest Research Institute, Addis Ababa, Ethiopia

  • Geotechnical Investigations, Ethiopian Construction, Design and Supervision Works Corporation, Addis Ababa, Ethiopia

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