Spatial monitoring of the extent gully erosion in agulu-nanka and its environs in anambra state using geo-information technologies

Soil erosion by water is one of the most important global land degradation problems mainly because of its negative onsite landscape effects such as loss of soil quality and offsite effects such as sedimentation of rivers, lakes and estuaries. This study tends to investigate and monitor the spatial extent of gullies in Agulu – Nanka of Anoacha and Orumba North LGA using Geo-Information Technology. In order to determine the land use and cover change of the gully erosion area, a 27 years change detection analysis was performed through the use of Landsat 4 TM of 1986, Landsat 7 ETM+ of 2000, and Landsat 7 ETM+ of 2013. A supervised classification of the MLC algorithm was performed through the aid of ERDAS 9.3 and the analysis was classified into 5 classes. The result indicates severe variation in all the three eroded/bare soil in the area throughout the study period. However, Eroded/Bare area land cover witnessed a decrease from 5.2% in 1986 to 2.87% in 2000 and increase from 2.87% in 2000 to 3.9% in 2013. This result indicates that man’s awareness to preserve the environment by applying mitigation and preventive measures especially in the areas prone to erosion might be encouraging.