Gully erosion mapping using ASTER data and drainage network analysis in the main ETHIOPIAN rift

Abstract

The Main Ethiopian Rift (MER) which is characterized by large elevation differences and occurrence of Precambrian basement rocks and post-Miocene volcanic rocks is severely affected by wide gullies and dynamically expanding into agricultural lands at an alarming rate. We study the potential contribution of Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) data and drainage network analysis to discern the gully erosion in the main Ethiopian rift. A maximum likelihood classification (MLC) with two classes, gullies and non-gullies, is used to extract different shapes and patterns of gullies. The drainage network analysis of SRTM and ASTER DEMs is used to describe the geometry of the gullies and their linkage with the drainage system. Two study areas are selected for this purpose. The accuracy assessment yielded two different results (89% and 77% accuracy). The linkage of the classification results with drainage network showed higher density distribution of feeders linked with gullies class.