Analysis of land use/land cover changes and their causes using landsat data in hangar watershed, Abay basin, Ethiopia

Abstract

This study analyzed land use/land cover (LULC) changes and their causes for the last 30 years from 1987 to 2017, covering an area of about 7673.87 km2 in Hangar Watershed, Ethiopia. The LULC maps were produced from three Landsat images of 1987 (Landsat-5 TM), 2001 (Landsat-7 ETM+) and 2017 (Landsat-8 OLI_TIRS) through pixel-based supervised image classification. The results indicated that there were an expansion in cultivated land (by + 24%, + 6%, and + 28%) and built-up area (by + 22%, + 19%, and + 37%) for LULC of corresponding years 1987–2001, 2001–2017 and 1987–2017. Whereas, there was a decrease in the forest (by − 20%, − 15% and − 32%), rangeland (by − 28%, − 13% and − 37%), grassland (by − 65%, − 6% and − 67%) and water body (by − 2%, − 54% and − 55%) for LULC of 1987–2001, 2001–2017 and 1987–2017 correspondingly. The major causes of these changes were identified as population expansion associated with increasing agricultural expansion, big tree clearing for building and wood extraction for fuel. The extraction of wood for fuel and building should be limited and legally managed, awareness of land use/land cover change hazard should be given for the community so that they shift the trends of land use and land cover change towards increasing vegetation covers which in turn can balance sediment yield.