Estimation of Soil Loss using Remote Sensing Data in a Regional Tropical Humid Catchment Area

Abstract

Soil erosion has been and continue to be a major threat to environmental degradation especially in the developing countries. Accurate estimation of soil loss will provide reliable information in the management and mitigation solutions to soil erosion. In this study, the soil loss in an erosion prone Anambra State of South East region of Nigeria was estimated. Due to the complex nature of the catchment characteristics of Anambra State, soil loss cannot be estimated precisely by mere application of conventional soil erosion model. Hence a site-specific methodology was developed and applied. Revised Universal Soil Loss Equation (RUSLE) was integrated with the Geographic Information System (GIS) of the environment using remote sensing to build the model. 40-years rainfall data was collated from the Nigeria Meteorological Agency and analyzed. The various parameter of RUSLE which includes: Rainfall Erosivity (R), Soil Erodibility (K), Topography (LS), Land Use and Land Cover (C), and Erosion Control practices (P) were developed and imposed into ArcGIS 10.6 to estimate the amount of annual soil loss in the area. The result indicated that about 27.58km2 (0.59%) of the study area have very low erosion rate of 0 – 5 t ha1year-1, while the rates of erosion in 1311.52km2 (28.01%), 538.59km2 (11.50%), 1649.08km2 (35.22%), 959.09km2 (20.48%), and 196.76km2 (4.20%) of the study area are 5 – 10, 10 – 15, 15 – 25, 25–50 and >50 t ha-1year-1 respectively. This knowledge will help decision makers in managing the land degradation problems in Anambra State of Nigeria.