Shoreline Change Analysis of the Coastline of Teshie in Accra.

Abstract

Coastal areas around the world are being shaped by natural and anthropogenic activities. These factors include ocean level rise, tides, geomorphology of the coastline, sand mining and coastal population increase. This study assessed the rate and extent of coastal erosion from 1986 to 2016 of the Teshie coastline; the socio-economic and cultural patterns (causes and effects) and the adaptive strategies undertaken by the locals of Teshie. Analyses of the shoreline change were computed using four historic years (1986, 1991, 2003 and 2016) of Landsat imageries over a 30-year period. The Digital Shoreline Analysis Systems based on formulae of the End Point Rate, Net Shoreline Movement and Linear Regression Rates were used. In addition, questionnaires and interviews were used to get first-hand information from the local inhabitants and concerned stakeholders. The results of the study showed 40.67% of the coastline to be eroding with 59.33% to be stable or accreting. The average erosion rate for the study is -0.41 m/yr and 0.52 m/yr for average accretion rate. The study had a range of shoreline change of -2.51 m/yr and 2.85 m/yr. The rate of erosion on the Teshie coastline has affected socio-economic and cultural livelihoods (including low fish catch, loss of landing sites and low beach turn-out). Unemployment and poverty were the main effects of socio-economic activities caused by coastal erosion. Effective coping strategies adopted include piling of sandbags and beach nourishment. The findings of the results showed that geomorphology and tidal waves have influenced shoreline change at Teshie. The study recommends regular and continuous study of the shoreline, to understand and predict shoreline changes. Keywords: Coastal Erosion, Coastal accretion, DSAS, Geographic Information System