International Journal of Environment and Climate Change 9(6): 331-342, 2019; Article no.IJECC.2019.026 ISSN: 2581-8627 (Past name: British Journal of Environment & Climate Change, Past ISSN: 2231–4784) Flood Vulnerability Assessment of Afikpo South Local Government Area, Ebonyi State, Nigeria Endurance Okonufua1*, Olabanji O. Olajire2 and Vincent N. Ojeh3 1Department of Road Research, Nigerian Building and Road Research Institute, Ota, Ogun State, Nigeria. 2African Regional Centre for Space Science and Technology Education in English, OAU and Centre for Space Research and Applications, Federal University of Technology, Akure, Nigeria. 3Department of Geography, Taraba State University, P.M.B. 1167, Jalingo, Nigeria. Authors’ contributions This work was carried out in collaboration among all authors. Authors EO, OOO and VNO designed the study, performed the statistical analysis, wrote the protocol and wrote the first draft of the manuscript. Authors OOO and VNO managed the analyses of the study. Author EO managed the literature searches. All authors read and approved the final manuscript. Article Information DOI: 10.9734/IJECC/2019/v9i630118 Editor(s): (1) Dr. Anthony R. Lupo, Professor, Department of Soil, Environmental and Atmospheric Science, University of Missouri, Columbia, USA. Reviewers: (1) Ionac Nicoleta, University of Bucharest, Romania. (2) Neha Bansal, Mumbai University, India. (3) Abdul Hamid Mar Iman, Universiti Malaysia Kelantan, Malaysia. Complete Peer review History: http://www.sdiarticle3.com/review-history/48742 Received 26 March 2019 Accepted 11 June 2019 Original Research Article Published 18 June 2019 ABSTRACT The study was conducted in Afikpo South Local Government covering a total area of 331.5km2. Remote sensing and Geographic Information System (GIS) were integrated with multicriteria analysis to delineate the flood vulnerable areas. Seven criteria were considered; rainfall, runoff, slope, distance to drainage, drainage density, landuse and landcover, and soil. The various criteria were fit into fuzzy membership classes based on their effect in causing flood. The fuzzy members of all criteria were then overlaid to generate the flood vulnerability map. The result of the flood vulnerability map shows that very low vulnerable zones cover 86.7% of the total area, low vulnerable zones cover 1.6% of the total area, moderate vulnerable zones cover 2.17% of the total area, highly vulnerable zones cover 2.3% of the total area while very highly vulnerable zones cover 7.3% of the total area. Built up was used as a measure of the effect of flooding on human lives and _____________________________________________________________________________________________________ *Corresponding author: E-mail: [email protected], [email protected] Okonufua et al.; IJECC, 9(6): 331-342, 2019; Article no.IJECC.2019.026 properties in Afikpo South Local Government. Built up covers a total area of 38.6km2. Over sixty eight (69.8%) of built up lies in very low vulnerable zone, 3% lies in low vulnerable zone, 3.7% lies in moderate vulnerable zone, 0.6% lies in highly vulnerable zone and 17.9% lies in very highly vulnerable zone. The study provides information on target areas that may be affected by flood in Afikpo South Local Government. This information is useful for decision making on flood early warning and preparedness as well as in mitigation preparedness within Afikpo LGA. Keywords: Flooding; vulnerability assessment; multicriteria analysis; fuzzy overlay. 1. INTRODUCTION to flood every year and more than 800 million are living in flood prone lands [4]. Flooding is caused Vulnerability can be defined as the degree of loss by heavy rainfall or when rivers overflow their resulting from the occurrence of a natural or banks and submerge dry lands or dam failure [5]. manmade phenomenon of a given magnitude to Flood is triggered by torrential rainfall have killed a known environmental constituent or set of many across the world. Increase in flood environmental constituents said to be at risk [1]. magnitude and frequency has been related to It is expressed on a scale from 0 (no damage) to climate change coupled with increasing 1 (total loss). The location of the areas where the population growth and urbanisation [6]. The largest economical losses due to natural or current trend and future scenarios of flood risk manmade disasters could occur is of invaluable requires that accurate spatial and temporal importance to urban planning. Therefore, there is information on potential hazards and risk of a need to complement natural hazard studies floods be carried out [7]. Flood risk analysis with vulnerability and risk assessments studies. provides a rational basis for prioritizing resources Such study could serve the purpose of early and management actions majorly in flood warning or total prevention of locating viable vulnerable areas [8]. Floods have consequences economic activities to the areas where they are on the economy, environment, human health and vulnerable. cultural heritage. Economic assessment of flood risk is simply about calculating the average Increasing numbers of natural disasters of which annual costs of damages or loss. Economic flooding is the greatest and most common is assessment of flood risk management measures being reported on major news media all around is about balancing the reduction of annual the world as causing great damages on existing damage cost against the average annual cost of infrastructures in urban areas. In April 2013 at risk reduction measures over their lifetime [9]. Cook County (Illinois), USA, critical facility that supplied power for a major international airport In Nigeria, recent flooding has left both the was inundated by catastrophic flooding just 4 government and the governed devastated [10]. inches away from the point of causing potential Flood displaces more people and causes disaster. Hurricane Sandy’s impact in 2012 on damages to properties and infrastructures than the East Coast of Illinois proved that there is a any other natural disaster in Nigeria [11]. In need for infrastructural preparedness and critical 2012, it was recorded that Nigeria suffered a loss examination of critical facilities across major U.S. of more than $16.9b in damaged properties, oil cities. According to [2] Iran has suffered from production, agricultural and other losses due to loss of over $ 3.7 billion as a result of flooding flood disaster. Increase in flood occurrence particularly along the southern shore of the coupled with lack of coping capacity and high Caspian Sea and in northern and northeastern levels of vulnerability of the populace have Iran. As reported by [3] in August 2001, flood continued to put many lives and properties at risk killed 210 people and cost $31 million in damage. in Nigeria [12]. While reliable infrastructures is During 2002-11, there were also dangerous and vital to human needs, currrent urbanisation smaller floods at the same places, which led to a trends in the country are defining negative loss of $65 million and the deaths of 28 people regards to flood vulnerability. Of particular [3]. concern is the fact that the impoverished part of the population who are most likely to settle in The increase in the rate of flooding across the flood risk zones are the least able to adopt world in recent times has been alarming. About measures for adaptation during flood disasters 70 million people across the globe are exposed [13]. 332 Okonufua et al.; IJECC, 9(6): 331-342, 2019; Article no.IJECC.2019.026 In Nigeria, several scientists at different times management planning. There are various ways have studied flood risk and vulnerability of measuring the impact of flooding in terms of assessment. Nkeki et al. [14] using the moderate the social, economic, environmental and resolution imaging Spectroradiometre (MODIS) geographical effects. This study takes into data of NASA Terra satellite reported that consideration the geographical dimension of geospatial methods are powerful techniques in flood impact in the study area. The aim of this mitigating and monitoring the effect of flooding study is to evaluate the spatial extent of flood risk along the Niger-Benue basin. Ojeh and Victor- in Afikpo South Local Government of Ebonyi Orivo [15] reported heavy inundation of State. Olajire et al. [17] posited that one way to farmlands soon after a heavy rainfall in Odah, mitigate the effects of flood is to ensure that all Iwhre-otah and Erorin communities in Oleh, areas that are vulnerable are identified and Isoko area of Delta State in the Niger Delta area adequate precautionary measures taken to of Nigeria led to loss of 0.608 kilometers ensure adequate preparedness, effective farmland at Odah, 0.441 kilometers at Iwhreotah, response, quick recovery and effective 0.547 kilometers at Erorin in 2011 and 0.485 prevention. kilometers at Odah, 0.425 kilometers at Iwhreotah and 0.598 kilometers in 2012 2. MATERIALS AND METHODS respectively. Their study revealed that all the crops cultivated in the area (cassava, melon, 2.1 Study Area yam, maize, plantain) were affected by flooding above 50 percent of total yield of each crop Afikpo South Local Government Area (LGA) is cultivated in the area except yam (46.9%). located between longitude 7° 40’ E to 7° 53’ E and latitude 5° 41’ N to 5° 57’ N (Fig. 1). Afikpo Okwu-Delunzu et al. [16] using Google image South is historically known as Edda. It is the and Shuttle Radar Topography Mission (SRTM) homeland of Edda people, an Igbo subgroup. Its of 2012 in Anambra East and environs, Nigeria administrative headquarters is at Nguzu Edda. discovered that 71% of the study area was liable Edda is Bordered by Uwana to the east, Akaeze to flooding of which farmlands accounted for to the west, Ohafia to the south and Amasiri to 41.7% of the landuse. Olajire et al. [17] observed the north. The basic occupation of the people in from their study of the Ala river basin, Akure, the LGA are farming and fishing.