An Appraisal of Gully Erosion along River Ngaddabul Floodplain, Maiduguri, Borno State, Nigeria

Abstract

The study focuses on appraisal of gully erosion along River Ngaddabul floodplain Maiduguri, Borno State, Nigeria. The objectives were to examine the factors and processes influencing gully development. The data used were obtained through measurements of the parameters such as gully length, width and depth at four locations. Also examine were slope angles, relief and vegetation of the topography and mapping of the gully patterns. The data were subjected to laboratory and statistical analysis. The findings revealed that factors that influence gullying (process) along the floodplain are rainfall amount, runoff taking advantage of footpaths, wheeled-tracks and soil texture. It was also revealed that human activities such as sand mining contribute to gullying processes by influencing mass wasting processes like slumping through undermining of channel banks leading to caving as well as collapse of channels. The construction of new houses along the road due to population pressure accelerated the gullying processes. The River Ngaddabul annual floods also contribute towards gullying (processes) by deepening the channels, leading to the initiation of new gullies on the slopes. In view of these, the study recommends that drainage channel should be constructed in the gully affected areas to check the volume of runoff influencing gullying. Sand quarrying should be restricted to specific locations along the road in order to prevent further disfiguring of the Ngaddabul channel through undermining processes along the channel.

Keywords: Floodplain, Runoff, Gully erosion, Gully pattern, Maiduguri.