An Assessment of Gully Erosion Progression and Vulnerability in Auchi Area in Edo State
Okeke U. Henry *
Cooperative Information Network, National Space Research and Development Agency (NASRDA), OAU Campus Ile-Ife, Nigeria
A. T. Alaga
Cooperative Information Network, National Space Research and Development Agency (NASRDA), OAU Campus Ile-Ife, Nigeria
Eguaroje O. Ezekiel
National Canter for Remote Sensing (NCRS), Jos, Nigeria
*Author to whom correspondence should be addressed.
Abstract
Soil erosion is one of the serious forms of land degradation in the Auchi area in Edo State. Efforts have been made to control the phenomenon but these have met with limited successes. Part of the problem is a poor understanding of the dynamics of the phenomenon in time and space. The general objective of the study is to evaluate the dynamics of Auchi gullies in the past three decades. The primary data were collected with the use of Global Positioning System (GPS) receiver to obtain the coordinates of locations of gully sites in the study area while field work and measurements were carried out to determine the characteristics of the gullies. The secondary data include: 1:50,000 topographic map, soil and geology maps as well as multi date satellite imageries of the area including: LandSat TM of 1981 and ETM of 2001, 2006 and 2014. The geo-data sets were processed and analyzed using Geospatial techniques. The results of the computation reveal noticeable changes in the gully area between 1987 and 2014 with most area vulnerable to the gully progression. The study concluded that the gullies are active, expanding with alarming annual frequencies and positive magnitude of change, engulfing other land area with diverse use. This has increased the vulnerability of the entire area to gully erosion while adopted control measures are only successful in area with gentle slope and less hydro activity.
Keywords: Gully erosion, remote sensing, vulnerability, morphology, DEM