Identification of critical erosion prone areas in Temengor Reservoir Basin using Universal Soil Loss Equation (USLE) and Geographic Information System (GIS)

Abstract

In this study, the Geographic Information System (GIS) was integrated with the Universal Soil Loss Equation (USLE) model to identify the risk of erosion at 360,000 ha in the Temengor Reservoir Basin. GIS was utilized as a tool for generating, manipulating and spatializing data from government agencies for sediment yield modelling and offering spatial input data to the erosion model. Meanwhile, USLE was used to predict the spatial distribution of the sediment yield on the grid basis. The five main parameters used in this study were the rainfall erosivity factor (R), topographic factor (LS), soil erodibility factor (K), crop management factor (C) and practice support factor (P). The R factor was calculated based on the annual rainfall data of the study area. The soil survey data was used to generate the K value and Digital Improvement Model (DEM) of the study area was used to generate LS factor. The values of C and P factors were derived from the land use map. After generating all parameters, analysis was performed to estimate the soil erosion using USLE model with spatial information analysis approach. It was discovered that the average annual soil loss in the study area was 8 t ha-1 year-1 and only 4% of the total area was under extreme erosion risk.