Impacts of shoreline changes and sea level rise in Ghana

Coastal communities from around the world face major challenges from sea level rise and shoreline change. In less economically developed countries, where coastal communities are often at subsistence level and highly dependent on local resources, challenges are greatest. Understanding how shorelines are changing and how the subsistence communities that live on them are adapting is critical for coastal management. Lagoon-barriers are common environments along the West African coast.

The dynamic nature of the connection between the lagoon and the sea make these of particular importance when considering shoreline change.  The Muni-Pomadze lagoon-barrier system in Winneba, Ghana, is being used as a case study to understand past and current shoreline change and the impact it is having on the local community. This work has revealed shoreline change since the 1970s. Shoreline mapping and comparison of aerial imagery shows that there has been land loss from the front of the barrier in the last 40 years that is probably associated with sea level rise. Erosion at the point where there is an intermittent connection between the lagoon and the ocean is resulting in a more open marine connection. This change has significant implications for the hydrology, sediment budget and biodiversity of the lagoon and associated coastal management.

The development of the ocean connection has been exacerbated by informal opening of the lagoon and this has sped up the changes along the barrier. Sea level rise projections for the system indicate where further changes to the barrier and to the lagoon may occur and can again be used for planning and management purposes.

Contact: Dr Sian Davies-Vollum