Assessment of Natural Geohazards in the Niger Delta Coast, Nigeria

The coastal zone is a dynamic environment under hydrodynamic forcings and adverse consequences of geohazards with potential for disasters. In this this studies, ASTER DEMs and LandSat 4,5 imageries have been analyzed in ArcGIS to determine the amount and rates of coastal subsidence, shoreline movements and coastal erosion and supplemented with secondary tide and wave data to model wave conditions in the face of climate change. Results indicates that the average ground subsidence was -2.6m at a rate of – 0.144m/yr. on the Bayelsa coast and -3.75m at a rate of -0.208m/yr on the Rivers coast. The rate of coastal erosion along the Akwa Ibom, Rivers and Bayelsa States in the Niger Delta coastline depicts a linear erosion of -13,054m, -17,519m and -81,532m in Akwa Ibom, Rivers and
Bayelsa respectively with erosion rates of -5.5m/yr along Akwa Ibom, -7.2m/yr along Rivers and -11.1m/yr along the Bayelsa coastline. The net shoreline retreat equivalent of incidental erosion was -8,590m along the Akwa coastline, – 9,240m along Rivers coastline and -70,383m along the Bayelsa coastline. Modeled hydrodynamics parameters predicted waves with mean wavelength of 178.95m, wave celerity of 13.01m/sec, group wave celerity of 11.27m/sec with maximum horizontal velocity of 0.4m/sec exerting an energy flux of 15, 902.00w/m. In considerations the stack realities of climate change, vulnerability assessment, integrated coastal zone management and climate change adaptation strategies for coastal protection are recommended.