Mapping Gully Erosion Using Remote Sensing Technique:

ABSTRACT

The study area Opi Nsukka and its environ Southeastern Nigeria, is located on latitude 6° 43' N- 7° 00 N and longitude 7 13' E - 7° 35' E. The aim of the study is to depict the spatial distribution of gully sites in the area using remote sensing technique. Soil erosion is described as an accelerated process under which soil is bodily displaced and transported away faster than it can be formed. The agents of soil erosion are principally running water, glacier waves and wind. These are natural agents of erosion. Anthropogenic factors also contribute to soil erosion, particularly in this zone. The landsat thematic mapper TM data of parts of Opi Nsukka was used to determine the structures associated with the area and to infer their influence on the gully erosion initiation and propagation. The landsat Tm data was processed using the ILWIS 3.2 Academic and ERDAS software's. The results obtained revealed numerous lineament at several parts of the satellite image. The rose diagram showed that the strikes and lengths of observed lineament were in two dominant structural trends that are in the NE-SW and NW-SW directions. The digital elevation model (DEM) and NDWI revealed a correction of low values with areas of high gully erosion susceptibility.