Wave dynamics and shoreline evolution in deltas: A case study of sandy coasts in the Volta delta of Ghana

Abstract

Erosion is a major global challenge facing coastal regions, and it is projected to increase on a regional to global scale as sea levels continue to rise. Deltas, which are important ecosystems, are particularly vulnerable due to their low-lying nature, subsidence, reduction in sediment supply, population increase, and exposure to an increasing frequency of extreme events. The need for sustainable management of these systems requires accurate estimates of shoreline dynamics at the local scale and higher spatial resolutions for engineering and decision making. We have assessed the shoreline dynamics of the Volta River delta in Ghana for a medium term of 12 years using high-resolution satellite imagery. The shoreline change rates are correlated with wave dynamics to explain the observed shoreline evolution within the delta. Our results confirm that erosion dominates the studied coasts with rates reaching as high as 31 m/yr close to the mouth of the delta where the water level shows a strong relationship with the shoreline change. These rates are evidenced by the destruction of fishing villages such as Fuveme located close to the mouth. Anthropogenic factors, such as the construction of sea defense projects, are also influencing erosion patterns across the study area. We recommend a softer approach for coastal management within the delta.