Vulnerability Assessment of Soil Erosion Based on Topography and Vegetation Cover in a Developing City of Orlu L.G.A, South East Nigeria

Abstract

The problem of erosion has over time been exacerbated by the development and constructions of buildings, roads, poor drainage system and other urban characters on areas transiting from rural to urban setting. This study set out to evaluate the vulnerability of Orlu L.G.A., Nigeria, to erosion in the face of increased anthropogenic activities using a combination of Geographic Information System (GIS) and soil characteristics. Soil samples were collected and analysed for geotechnical/physical properties, slope was also measured. Satellite images where analyzed for changes in land use and land cover, while GPS coordinates of different points in the area were obtained and interpolated into a map to create digital elevation model (DEM). With the aid of the GIS, slope pattern was established. Urbanization has triggered some erosion problems in the study area. Gully formation was seen to have been induced mainly by poorly designed construction works. The study also established the degree and length of slope, the soil and inherent geologic formations of the study area are the primary factors of the gully erosion in the study area. From the GIS generated images, the northern and western section of the study area are prone to erosion hazards and this was confirmed by a field reconnaissance survey.