The State of the Lower Volta Delta Beaches in Ghana from Field Observations

Field observations along West Africa are of extreme importance for understanding rapid beach geomorphological changes. Here, we conducted comprehensive field surveys to understand the geomorphological and hydrodynamic conditions of Ghana's lower Volta Delta. Over five months, in situ data were collected along 90 km of coast, examining temporal bathymetry, beach profiles, beach width variations, waves, and grain sizes. The primary objective was to determine the factors behind the significant coastal erosion and flooding, destabilizing the coastal ecosystems and communities. Results show that grain sizes are in the range of 0.2 < D ₅₀  < 0.5 mm. The beach slope, which varies between the flattest 0.4% at Blekusu, Keta Fort, Atiteti and the steepest 21% at Atorkor, is substantial for the returning floods experienced at some sections. Despite the same regional climatic environment, the study reveals contrasted coastal behaviors, with different sections of the Delta exhibiting distinct alterations in beach profiles and widths. Global wave model data (e.g. ERA5), widely used for coastal assessment in terms of magnitude, are significantly inconsistent with in-situ measurements in shallow water as found this study which could affect modeling of wave dynamics in shallow waters. This work serves as a database for current and future projects.