Application of Geospatial Technologies in Assessing Gully Erosion in the Humid Tropics of Eniong Offot, Uyo, Akwa Ibom State

Abstract

The application of geospatial tools in geomorphic mapping plays an essential role in the understanding of both landscape evolution and natural hazards (notably gully erosion) across scales. This study investigates the pattern and influence of gully erosion in Etim Umana axis of Eniong Offot, Uyo in Akwa Ibom State with emphasis on geospatial assessment of land use/cover, elevation, and flow accumulation. Map analyses of land use/land cover reveals that urbanization/population growth representing 41.6 percent, scattered cultivation representing 22 percent, and paved surface representing 16.7 percent coupled with high rainfall which together accounted for a total of 80.3 percent of the outstanding drivers of gully migration and expansion in Etim Umana site while secondary vegetation and bared ground accounted for 19.7 percent in the area. The analysis of vegetation using Normalized Difference Vegetation Index (NDVI) and three digital elevation model revealed that scarcity of vegetation cover, high to moderate relief, and the bedding plains of the coastal sands deposits also exercised the strong influence on the gully migration in the area. This paper concluded that gully erosion in the Etim Umana area is caused by high incidence of rainfall and surface configuration but accelerated by anthropogenic activities (urbanisation, farming, engineering/construction works). This study recommends the construction of existing drainage systems from roads to the nearby rivers for appropriate regulation of surface runoff generated by heavy rainfall from the already over-stressed facilities in the Offot area of Uyo.