Abstract:
Estuarine shorelines similar to marine coastlines are highly dynamic and may increase disaster risk in vulnerable
communities. The situation is expected to worsen with climate change impacts and increasing anthropogenic
activities such as upstream water management. This study assessed shoreline changing trends along the Volta river
estuary in Ghana as well as the marine coastline using satellite imageries, orthophotos and topographic maps
spanning a period of 120 years (1895, 1990, 2000, 2005 and 2015). Linear regression method in the Digital Shoreline
Analysis System (DSAS) was used to determine the estuary shoreline migration trend by estimating the shorelines
rate of change for the eastern and western sides of the estuary. The rates of change of the marine coastlines on
the east and west of the estuary were also estimated. The results show that the eastern and western shoreline of
the estuary are eroding at an average rate of about 1.94 m/yr and 0.58 m/yr respectively. The coastlines on the
marine side (eastern and western) are eroding at an average rate of about 2.19 m/yr and 0.62 m/yr respectively.
Relatively high rates of erosion observed on the eastern estuarine shoreline as well as the coastline could be
explained by the reduced sediment supply by the Volta River due to the damming of the Volta River in Akosombo
and the sea defence structures constructed to manage erosion problems. The trend is expected to increase under
changing oceanographic conditions and increased subsidence in the Volta delta. Effective management approach,
such as developing disaster risk reduction strategy, should be adopted to increase the resilience of the
communities along the estuarine shoreline and increase their adaptive capacity to climate change hazards and
disasters.
