Spatio-temporal analysis of vegetation and oil spill intensity in Ogoniland

Hafsat Saleh Dutsenwai,A.I Tanko,Baharin Bin Ahmad,Abubakar Mijinyawa

doi:10.21833/ijaas.2017.04.013

Abstract

Ogoniland, Niger Delta Nigeria is an area that has been subjected to terrestrial oil spills from the beginning of oil exploration in the 1950s till date. Despite many studies and practical efforts by different organizations and multinational companies, oil spills continue to occur and their impacts persist. These oil spills are regarded as the major cause of environmental degradation in the study area. The objective of this study was to ascertain the fact that oil spill is the major cause of environmental changes in Ogoniland using Normalized Difference vegetation Index (NDVI) and statistical methods. Remote sensing satellite data (Landsat 5TM (1984), Landsat 7ETM+ (2013, 2014 and 2015), and geographical coordinates of spill locations were used to observe vegetation dynamics with respect to the intensity of oil spills. For vegetation dynamics, the geographical coordinates were used to observe temporal variations of NDVI values at each spill point while statistical analyses were used to identify the relationships between the intensity of the spills and the changes in vegetation. It was observed that changes in vegetation quality and quantity can be attributed to oil spill occurrences, however, the level of change in vegetation cannot be ascribed to the frequency or intensity of the oil spills. Finally, this study asserts that oil spill is the major cause of environmental changes in the study area. (C) 2017 The Authors. Published by IASE.

Highlights

Ogoniland, Niger Delta Nigeria is an area that has been subjected to terrestrial oil spills from the beginning of oil exploration in the 1950s till date
The data were further converted to features as points in order to find their positions on the satellite images
Four different approaches were used in this study to determine the logic behind the perception that high environmental degradation in Ogoniland is caused by the alarming number of oil spills

Summary

Introduction

Niger Delta Nigeria is an area that has been subjected to terrestrial oil spills from the beginning of oil exploration in the 1950s till date. Despite many studies and practical efforts by different organizations and multinational companies, oil spills continue to occur and their impacts persist. These oil spills are regarded as the major cause of environmental degradation in the study area. The objective of this study was to ascertain the fact that oil spill is the major cause of environmental changes in Ogoniland using Normalized Difference vegetation Index (NDVI) and statistical methods. The monitoring of terrestrial oil spills has received very little attention This is due to the regional and small scale character of the contaminations of oil spilled on land they are sometimes complicated by several mixed spectral signatures such as that of vegetation (dead or recovering), or contaminated sands and soils (Hese and Schmullius, 2009). It is important to study problems of oil spill in the terrestrial environment especially in a country like Nigeria, based on the fact that the country’s economy depends highly on oil

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