Land use dynamics and base and peak flow responses in the Choke mountain range, Upper Blue Nile Basin, Ethiopia

Land use dynamic has become a major driving force of environmental problems that affects hydrological processes. This study aimed to detect the patterns of land use dynamics and its causative factors in the Muga and Suha watersheds of the Choke mountain range, Ethiopia. Decadal temporal land use mappings were generated using remote sensing integrated with field data and spatial analysis tools, which were conducted for the years 1985, 1995, 2005 and 2015. The land use classification results showed that between 1985 and 2015, grass and shrub land area coverages were decreased by 18.1% and 11.9%, respectively. While agriculture and urban area coverages were increased by 29.6% and 0.53%, respectively. In the Muga-Suha watershed, the impacts of land use dynamics to the stream base flow or the low flow in the dry season and the peak flow in the wet season were also assessed using the gauged stream flow data between 1985 and 2004. Base separation technique result indicated the base flow (the low flow) in the dry season decreased by 0.73 m(3)/year in Suha and by 0.37 m(3)/year in Muga watersheds. The land use dynamics impact on the base flow showed a consistent decline trend owing to the reduced recharge in the dry season. Similarly, the peak flow in the wet season increased as high as 94% in Suha and 50% in Muga watersheds in the considered period.