Effect of Eucalyptus expansion on surface runoff in the central highlands of Ethiopia

Abstract

Introduction: Land use/land cover change can affect the ecological processes of an area such as hydrological cycle. The change in the condition of water resources of an area could be a good indicator of changes in ecosystem function as a result of altered land use/land cover. Eucalyptus expansion in central Ethiopia is one of the recent land use/land cover changes causing controversy on its potential ecological effect. This study was designed to evaluate effects of three adjacent land uses/land covers, i.e. cultivated land, grassland and Eucalyptus woodlot on surface runoff in Meja River watershed, central Ethiopia. Methods: The rainfall amount at each study catchment was collected using the rain gauge installed to record daily rainfall amount. The three land use/land cover types in each study catchment were selected for comparison as treatments. Four replications of each land use/land cover were used forming a total of 12 runoff plots. The rainfall and runoff data were collected twice a day for 91 days. Results: The study found that land use/land cover significantly affects surface runoff generated from the plots. Higher runoff was recorded from cultivated land. There was no significant difference on runoff volume between grassland and Eucalyptus woodlot. Conclusions: This shows that expansion of Eucalyptus on grassland could not have significant impact on surface runoff generation but if planted on previously farmland could reduce surface runoff.