Like low-lying sandy coasts around the world, the Ghanaian coast is experiencing increasingly frequent coastal flooding due to climate change, putting important socioeconomic infrastructure and people at risk. Our study assesses the major factors contributing to extreme coastal water levels (ECWLs) from 1994 to 2015. ECWLs are categorized into low, moderate, and severe levels corresponding to the 30th, 60th, and 98th percentiles, respectively. Using these three levels over the Pleiades satellite-derived digital elevation model topography, potential flood extent zones are mapped. ECWLs have the potential to flood more than 40% of the study area, including socioeconomically important sites such as tourist beach resorts, Cape St. Paul lighthouse, and Fort Prinzenstein. In this study, all coastal flooding events recorded by the municipality of Keta fall within the 98th percentile category. Our results show a gradual increase in the frequency of flooding over the years. Flooding events are caused by a compound effect of the tide, sea level anomaly, waves, and atmospheric conditions. Finally, while wave run-up is the major contributor to coastal flooding, the tide is the one varying most, which facilitates a simple early warning system based on waves and tide but adds uncertainty and complicates long-term predictability.

Certain communities along the coast of Ketu South Municipality in south-eastern Ghana, remain vulnerable to coastal flood events from storm surges, high tidal waves, lagoon overflow, and heavy rainfall. However, the local conditions that make these communities vulnerable are poorly understood and knowledge on which communities are most vulnerable is lacking. This study improves the conceptual understanding of different dimensions of vulnerability that exist across the communities and the various levels of vulnerability that each exposed community exhibits. The study surveyed 354 household heads from selected flood-prone communities including Blekusu, Agavedzi, Salakope, Amutsinu, and Adina. The survey collected data on demographic, social, economic, physical, exposure, and adaptive capacity to flood hazards. The data was then used to construct composite vulnerability indices at community levels. Results from the study demonstrate that the communities have different levels of vulnerability as a result of differences in their exposure, sensitivity, and adaptive capacity levels. The willingness to relocate as an adaptation strategy was determined by household flood duration, number of livelihoods, and sea defence preference. These results are relevant to flood disaster management programs and the adoption of effective adaptation measures that take into account local knowledge. The findings imply that interventions aimed at reducing vulnerability should take into account household characteristics, as well as flood exposure, and adaptive capacity factors.

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.

Field measurements of longshore sediment transport have been performed in the surf zone along Denu Beach, located in the Volta Region of Ghana, West Africa. This study consisted of measuring sediment transport rates by the deployment of modified versions of Kraus streamer traps on a cross-shore distance, which was about half the average surf zone width. In addition to the measured transport rates, data on waves, longshore currents, and other morphological parameters were collected with simple and low-cost instrumentation. In total, about 22 datasets were obtained through several days of data collection spanning a period of 5 months. Mathematical formulae proposed by CERC (1984), Kamphuis (1991), and the new van Rijn (2014) were used to compute theoretical transports for the entire surf zone, which were validated by measured data. Applying the CERC equation with a K-value of 0.39, the theoretical transports were about one order of magnitude higher than the measured rates. The rates computed by the Kamphuis formula were slightly higher than those yielded by the van Rijn equation. They produced values that were, on average, about 3.5 and 2.9 times higher than the measured rates, respectively. This study then confirmed the capabilities of both the Kamphuis and van Rijn equations to provide closer estimates of longshore sediment transport on Denu Beach. It especially sheds light on the new van Rijn formula, which has not been used extensively in LST quantification across the world. We, therefore, concluded that both the Kamphuis and van Rijn equations could be particularly useful to local engineers in the prediction of LST prior to the design of coastal protection structures. Further long-term studies employing available cutting-edge technologies were also recommended to provide more information on longshore transport not only in Ghana but also in the entire Gulf of Guinea and for the establishment of a reliable sediment budget for the country and the entire region.