Shoreline Change Analysis of the Coastline of Teshie in Accra, Ghana

Abstract

The coastal zones of Ghana, including Teshie are attacked by coastal processes and human activities which are changing its morphology and threatening life and properties. Studies on shoreline changes in Ghana have been regionally based. However, sustainable coastal zone management of risks-prone areas focuses on specific shoreline sectors. Thus, this study was carried out in Teshie an erosional hotspot in Accra to assess the extent and the rate of shoreline change between 1986 and 2016 as well as investigate the underlying causes. The analyses of the shoreline change were undertaken using three Landsat years images 1986, 2003 and 2016. The shoreline was analysed using Digital Shoreline Analysis Systems software in ARCGIS. Field exploration and literature review were conducted to decipher the driving forces of the shoreline dynamics. Results showed that 40.7% of the entire coast was experiencing erosion with 59.3% accreting between 1986 and 2016. Average NSM accretion over the period is 12.7 m with an annual rate of 0.9 m/yr. Average coastline erosion was 10.4 m with an annual erosion rate of 0.7 m/yr. A multiplicity of natural and anthropogenic factors such as tidal and sea level rise, sand and rock mining are the driving forces for the changes in the Teshie coastline. There is the need for the development of an integrated coastal zone management policy which will include establishing a coastal protection structure and enforcing regulations on beach sand and rock mining to safeguard and protect the coastline of the locality