Comparison Of Morphological Changes Along The Arcuate Niger Delta Coastline (From Part Of Delta State To Part Of Rivers State

ABSTRACT

This study analysed the rate of coastal erosion and accretion along the Niger Delta coastline. The study compared Morphological changes along Ogulagha (Delta State), Twon-Brass (Bayelsa State) And Bonny Island (River State) coastlines over a period of 30 years (1986-2000-2016). Geospatial techniques were used to carry out the assessment. Satellite image of landsat 5 Thematic Mapper (TM) of December 1986, landsat 7 and 8, Enhance Thematic Mapper (ETM+) of December 2000 and 2016 of path 188 and row 57 acquired online from the archive of United State Geological Survey earth explorer data archive. Arcgis 10.0, Arc map and Arc catalogue were used to vectorise shapefiles and digitize the various features from the imageries, to generate the map of study area. Spatial , spectral and radiometric enhancement of the imageries were carried out using ERDAS Imagine and image further classified using Maximum Likelihood Classifier (MLC) to generate Land Use Land Cover map (LULC) classified into vegetation cover, bare surface cover, water bodies and built-up surface cover. In the assessment of the entire shoreline, approximately 4.1% of the shoreline revealed accretion. The mean shoreline change rate for all transects (accreting, stable and eroding) measured approximately 20,000Ha of the entire 470309.8 Ha, maximum accretion and erosion measured 53877.8 Ha in 1986 and 87580.4 Ha 2016.The major accretion was detected within Brass(Bayelsa State), Bonny(River State), Andoni(River State) and Ibeno(Akwaibom State), due to prevailing operation like oil wells, recreation activities and commercial/residential activities in the case of Opobo town, whilein 2016; Brass(Bayelsa State), Degema(River State) and Eastern Obolo(Akwaibom State) section, erosion was also dominant which estimated approximately 50% of the shoreline revealing entire erosion scenario. 1986 recorded vegetative cover of 27.4% which reduced to 22.9% in 2016 a change attributed to massive conversion of vegetative cover for anthropogenic activities in the area, a minor change of approximately 2% in the cover of water body. The study concluded that major erosion cases are due to the changing climate and the velocity of flow of major estuaries into the ocean.

Keywords: Shoreline Morphology, Niger Delta, Erosion, Accretion, GIS