Volume 2, Issue 4, July - December, 2025

Coastal Shoreline Variability, Erosion and Climate Change Dynamics in Bonny Island, Niger Delta, Nigeria

Andy Etta Bisong¹, Fidelis Ankwo Abija^2,3

¹Department of Geography and Environmental Science, University of Calabar, Calabar, Nigeria
²Geoenvironmental and Geotechnics Unit, Dept. of Civil Engineering, Federal University of Environment and Technology, Koroma/Saakpenwa, Ogoni, Nigeria
³Centre for Geomechanics, Energy and Environmental Sustainability, Port Harcourt, Nigeria

ABSTRACT

Spatio-temporal analysis of coastal shoreline dynamics of Bonny Island of Rivers State, Nigeria was evaluated using Landsat ETM of 2000, 2005, 2010, and Landsat 8 OLI of 2015 and 2020 spanning a period of 20 years. The satellite images with a resolution of 30m by 30m were digitized as polylines in geo-processing steps using ArcGIS 10.7 and bands (red, blue and green) of each image combined using Erdas Imagine 9.2. The shoreline of 2000 was superimposed on 2005 shoreline, 2005 shoreline on 2010, 2010 on 2015 and 2015 on 2020. Thereafter, overlaid maps were converted to polygons using features to polygon module. The polygons were grouped to advanced (accretion) or retreat (erosion) with which spatial query was applied. The result revealed that Bonny Island lost 1.37 km2 (61.99%), 0.05km2 (2.04%), and 2.55km2 (59.72%) of land from 2000 to 2005, 2005 and 2010 and; from 2010 to 2015 respectively while 1.05 sq km (24.08%) was gained between 2015 and 2020. On the whole, 2.04 km2 (50.75%) of land was lost from 2000 to 2020. The study concluded that Bonny Island shoreline experienced more erosion than accretion from 2000 to 2020. The study recommends periodic monitoring of the coastal area on monthly and yearly bases; establishment and enforcement of development setbacks, implementation of development control measures as well as the introduction of integrated coastal zone planning and management within the Niger Delta region to reduce hazards and protect the beautiful sand beaches.

Keywords: Shoreline, GIS, Satellite imageries, Erosion, climate change impacts

Discovery Nature, 2025, 2(4), e14dn3141

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DOI: https://doi.org/10.54905/disssi.v2i4.e14dn3141

Published: 12 December 2025