Short-term shoreline evolution trend assessment: a case study in Glefe, Ghana

Abstract

The growing economic, social and ecological importance of coastal areas in Ghana has increased the challenges associated with sustainably managing the coastal resources. The coastal areas have become more prone and vulnerable to natural and human-made hazards such as coastal erosion. Shoreline retreat is recognised as a burgeoning threat because of global climate change and other anthropogenic activities that alter the natural processes sustaining beaches and coasts. This article describes an application of Real-time Kinematic-Global Positioning System (RTK-GPS) technology and digitising of shorelines from orthophotos to detect and analyse the spatial changes as well as quantify the result of shoreline change at Glefe, a suburb of Accra in Ghana. Shoreline positions from a 2005 orthophoto and a 2011 RTK-GPS survey were overlaid in MATLAB (Matrix Laboratory) and the average rate of change determined using the endpoint rate (EPR) method. The shoreline change rate determined for Glefe between 2005 and 2011 was 1.2 m/a ± 1.3 m/a, indicating a relatively high rate of erosion. Outcomes of the case study can be used as a basis for a sustainable integrated management plan for the coastal area.