An assessment of the contribution of fluvial sediment discharge to coastal stability: A case study of Western Region of Ghana

Abstract

Fluvial sediment discharge to coastal area contributes to the stability of the coast. Deposition of fluvial sediment discharge is an important source of beach nourishment, nutrient for aquatic ecology and habitats. However, human development and interventions on rivers in the form of dams and flood alleviation schemes tend to reduce fluvial sediment supply to the coast, thus impacting on coastal stability and geomorphology. This paper assessed the contribution of fluvial sediment discharge to coastal stability for the study area. Multi-temporal topographic data acquired in 1974 and 2005; flow data on major rivers in the study area and field observations were used. Digital Shoreline Analysis System was for computation of shoreline change rates. Applying the power regression relation, sediment discharge by rivers was computed for rivers in the study area. The study revealed that rivers in the catchment supply about 1.8 × 10 5 tonnes of sediment to the shores daily, thus supporting coastal stability. Results of shoreline change showed relatively stable beach at the mouth of rivers and lagoons due to the sediment discharge. It is recommended that policies are implemented to reduce the impact of dams and beach sand mining activities along river channels to ensure the stability of Ghana's Western coastline and the coastline of neighbouring countries.