Multi-decadal shoreline changes in Eastern Ghana—natural dynamics versus human interventions

• DOI: 10.1007/s00367-023-00758-x
• Publication Date: 2023-11-02T11:03:01Z
• Authors: T. Mann; A. Serwa; A. Rovere; E. Casella; K. Appeaning-Addo; P.-N. Jayson-Quas...; T. Mensah-Senoo; K. Trstenjak; B. Lassalle; M. Flitner; H. Westphal
• Keywords: Beach morphodynamics; Coastal erosion; Progradation; Longshore drift; Sedimentary budget; River delta

Abstract Human infrastructures, such as dams, seawalls, and ports, can affect both the sedimentary budget nearshore hydrodynamics, enhancing accelerating loss or gain of coastal sediments. Understanding processes factors controlling beach morphodynamics is essential for implementing adequate adaptation strategies in areas, particularly those regions where protection measures are scarce. This study analyzes shoreline changes Keta Municipal District, located southeastern Ghana (West Africa). area characterized by input Volta River, forming a river delta situated to west, i.e., updrift, our site. Following construction two dams (Akosombo Kpong) on River 1965 1982, groins revetments have been built along coast between 2005 2015 reduce high rates erosion this area. Here, we explore influence these hard constructions using historical maps satellite images complemented survey undertaken with differential GNSS 2015. The multi-decadal evolution 1913 reconstructed 90 km suggests that local region predate indicating structures might not be primary driver area, previously suggested. We emphasize dynamics under conditions high-energy longshore drift, modified anthropogenic drivers sand mining, play key role long-term coast. Our results also show infrastructures halt result localized accretion down-current coastline towards border Togo, highlighting need transnational perspective addressing problems caused erosion.