A REMOTE SENSING-BASED APPROACH FOR HYDROGRAPHIC MAPPING OF COASTAL AREA OF EASTERN OBOLO LGA OF AKWA IBOM STATE OF NIGERIA

Abstract

Remote sensing-based approach being the acquisition of data from a distance object without having physical contact with it, is a reliable method of acquiring hydrographic information of coastal areas. Hydrographic mapping involves mapping of water related environments. Eastern Obolo LGA of Akwa Ibom state of Nigeria being a coastal environment faces a lot of coastal hazards including coastal erosion, siltation and dumping of wastes along the coastal waters. Aiming at applying remote sensing based approach for hydrographic mapping of the study area, the objectives included acquiring/processing a medium resolution satellite imagery of the area, determining bathymetric data of its coastal waters by empirical modelling, classifying Landcover/Landuse (LULC) of the area and generating its hydrographic map. The methodology used involved acquiring/processing Landsat 8 OLI satellite imageries using ArcGIS Pro and ENVI 5.3. The results revealed that Eastern Obolo LGA has 242.58 km2 land coverage, 56.25 km2 forest and moderate size areas of cropland and open space. Bathymetry result shows shallow area of 4.48 km2, moderate depth area of 58.09 km2 and much expanse of deep and very deep area. Data validation with that gotten from SPDC gave a correlation coefficient
of 0.69 suggesting moderately accurate data with good degree of confidence.

Keywords: Remote sensing, Hydrographic, Bathymetric, Mapping, Coastal area