SANDSPIT ELONGATION AND LITTORIAL DRIFT AT THE VOLTA RIVER MOUTH, GHANA

Abstract

 The Volta River mouth, located in Ghana, West Africa possesses a significantly elongated estuary sandspit. Rapid development of the sandspit causes the estuary water levels to rise during floods, resulting in flood related disasters. In developing countries, acquisition of detailed data on such events is limited which hinders extensive research on mitigation measures. In this study, satellite images were acquired after 1984 to quantitatively examine the morphology of the sandspit at the river mouth. From the study, it was observed that the sandspit elongated at a constant speed (approximately 580 m/year) before the construction of a groyne system. In addition, there were periodic breaching of the sandspit resulting in a change of river mouth position. Based on results obtained for the sandspit growth rate and incorporating the depth of closure and berm height values from previous studies, the amount of littoral drift was estimated. The value obtained was one to two order larger than the values reported in other parts of the world including that of Japan.