Coastal Flood Mapping of Eastern Obolo and Ibeno LGAs of Akwa Ibom State of Nigeria, using SRTM and Satellite Imageries

Abstract

Coastal flooding is one of the devastating noticeable hazards in Eastern Obolo and Ibeno LGAs of Akwa Ibom State, originating from incidence such as the rise in sea level, increase in precipitation, poor drainage network and some anthropogenic activities. Being the two coastal LGAs in the state directly bordering the Atlantic Ocean, there is coastal flood menace and its associated hazards such as waste deposits after the flood, inundation of people’s houses, covering of the surrounding environments with debris from water, rendering of agricultural lands unusable and alteration of the coastal ecosystem. To provide basic information that will help tackle these problems, this study mapped the coastal flooding of the area, using Shuttle Radar Topographic Mission (SRTM) and satellite imageries, with the objectives of determining the area at risk of coastal flooding, and to produce coastal flood map of the area. SRTM and satellite imagery (Landsat8 OLI 2017) were used to classify the area into coastal flood risk zones based on factors such as elevation and slope. Landcover/Landuse classification into Built-up area, Vegetation, Mangrove and Water bodies was equally done. The result of the study indicates that 60% and 47.12% of the land masses are at risk of coastal flooding in Eastern Obolo and Ibeno LGAs respectively. Base on the findings, the study recommended the establishment of a hydrometric gauging (water level monitoring) stations in the low-risk areas along the coastal lines to monitor the level of rising in coastal water which brings about the coastal flood.