GIS-based Assessment of Short Term Shoreline Changes in the Coastal Erosion-Sensitive Zone of Accra, Ghana

Research Article

GIS-based Assessment of Short Term Shoreline Changes in the Coastal Erosion-Sensitive Zone of Accra, Ghana

This study set out to identify factors that contribute to erosion-induced shoreline changes and determine the rate of shoreline change for Accra, Ghana. Shoreline changes were compared between 1990 and 2010 using aerial photographs and Landsat satellite imagery within Geographic Information System (GIS) environment. The Transect approach was used to delineate the entire shoreline and the length was divided into 435 transects. A spacing of 100 m and a transect length of 3800 m were applied to detect all the changes that have occurred along the shoreline. The Digital Shoreline Analysis System (DSAS) was used to analyze the shoreline in order to determine the End Point Rate and the Linear Regression of Rate of Change. The results revealed that 21847.978 m of the coastal areas were altered during the period with a rate of erosion of 3.0500 m year^-1 with Accra Central, Osu and James Town recording the highest level of shoreline erosion. The activities that contribute to the shoreline change aside the challenging natural factors are sand mining, hard and engineered structures on the shore and other commercial and social activities. The occurrences of shoreline erosion have contributed to the degradation of these coastal ecosystems, loss of human settlements and livelihood. From the results, it was estimated that by 2015, the rate of erosion would be about -6.1 m year^-1 and by 2020, the rate of erosion would be -30.2 m year^-1. It is therefore essential to implement precautionary measures to mitigate the risk of shoreline erosion within this sensitive zone.

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Frederick Ato Armah, 2011. GIS-based Assessment of Short Term Shoreline Changes in the Coastal Erosion-Sensitive Zone of Accra, Ghana. Research Journal of Environmental Sciences, 5: 643-654.

DOI: 10.3923/rjes.2011.643.654

URL: https://scialert.net/abstract/?doi=rjes.2011.643.654

Research Journal of Environmental Sciences

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Frederick Ato Armah

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Research Article

GIS-based Assessment of Short Term Shoreline Changes in the Coastal Erosion-Sensitive Zone of Accra, Ghana

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