Gelleh et al
Greener Journal of Environmental Management and Public Safety Vol. 5 (2), pp. 024-032, April 2016.
ISSN: 2354-2276 © 2011-2016 Greener Journals
Manuscript Number: 011316005
Flood Vulnerability Assessment in Lagos City Using Multi – Criteria Analysis
Gelleh I. Daniel1, Ibidun O. Adelekan2, Okeke U. Henry1
1Cooperative Information Network, National Space Research and Development Agency, Obafemi Awolowo University Campus Ile-Ife Osun State, Nigeria.
2Department of Geography, University of Ibadan, Ibadan Nigeria.
Flood disaster is considered as a major natural hazard due to its devastating effects on the affected area. Geographical Information System (GIS) is integrated with Multi-Criteria Decision Analysis (MCDA) method and is used to analyse the flood vulnerable areas. The actual aim of this is to provide a more flexible and accurate decisions to the decision makers in order to examine the effective factors causing flood. The study considers eight factors that contribute to flood within the Oke-Afa water catchment in Lagos State, Nigeria which include rainfall, stream order, distance from stream, elevation, land use, slope, soil, and geology. Multi-criteria evaluation approach which involves ranking method and pair-wise comparison method (Analytical Hierarchical Process-AHP) was used to calculate the weights of each factor. Using AHP the weightage derived for the factors are 0.38%, 0.21%, 0.16%, 0.10%, 0.06%, 0.04%, 0.03%, 0.02% respectively for rainfall, stream order, distance from stream, elevation, land use, slope, soil, and geology. The study also made use of Landsat satellite image of 2014 and topographic map of Lagos state to classify the different land use types within the area. The digitized topographic map covering the study area was used to generate the Digital Elevation Model (DEM) and contour map respectively. At the end of the study a flood vulnerability Map of the vulnerable areas within Oke-Afa was generated with a view to assisting decision makers on the menace posed by the disaster.
Keywords: Geographical Information System, Multi-Criteria Evaluation, Vulnerability, Flood, Analytical Hierarchy Process.
Jonkman, S. N. and Vrijling, J. K. (2008): Loss of Life Due to Floods, Journal of Flood Risk Management, Vol. 1, pp. 43-56.
Olusegun E, (2004) Towards Comprehensive, Long-Term Approaches to Disaster Management in Nigeria, ISDR INFORMS, Issue 4, 2004.
Yahaya, S, Ahmad, N. and Abdalla, R. F (2010): Multi-criteria analysis for flood vulnerable areas in Hadejia-Jama’are River basin, Nigeria. Journal of Scientific Research, Vol. 42, No. 1, pp. 71–83.
Yalcin, G., (2002): Analyzing flood vulnerable areas with Multi-criteria evaluation, Unpublished MS Thesis in GGIT METU, Ankara. http://www.isprs.org/istanbul2004/comm2/papers/154.pdf