Shoreline Morphology along Barrier and Mahin Transgressive Mud Coast of Nigeria

Abstract

Coastline is one of the most import line features on the surface of the earth. Information about the coastlines morphology is required by the coastal management for proper coastal planning. Over 60% of the world population lives within few km to the coast. By the turn of the century two-thirds of the population (3.7 billion) in developing countries have occupied the coast. Consequently, unless careful environmental management and planning are instituted, severe conflicts over coastal space and resource utilization are likely, and the degradation of natural resources will close development options. In addition to the population pressure, the world’s coastal areas and small islands are highly vulnerable to climate change. Low‐lying delta, barrier coasts, low‐elevation reef islands, and coral atolls are especially sensitive to the rising sea level, as well as to changes in rainfall, storm frequency, and intensity. The research examined the shoreline changes over time in barrier lagoon coast and mahin mud coast of Nigeria. Satellite images comprising of Landsat MSS, ETM and OLI of 30m by 30m of 1990, 2000, 2010 and 2020; were used as the sources of data. The satellite images underwent series of geo-processing. The bands (red, blue and green) of each image were combined using Arc Map 10.4. The images were added as layer whereby the shoreline from each image was digitized as polylines. The shoreline of 1990 was overlaid on that of 2000, shoreline of 2000 was overlaid on 2010, 2010 on 2020 and that of 1990 on 2020. Thereafter, overlaid maps were converted to polygons using Features to Polygon module of ArcGIS 104. The polygons were grouped to advanced (land gained) or retreat (land lost) with which spatial query was done. The result revealed that Barrier and -mahin mud coast lost about 56.4622km2 of land while 4.44275km2 was gained between 1990 and 2000 whereas between 2000 and 2010; 6.65259km2 was lost while 14.0042km2 of land was gained. During the period between 2010 and 2020, the analysis showed that 15.4195km2 was gained while 12.2509 km2 was lost. The percentage change was highest between 1990 and 2000 with 85.41% of land loss.