Impact of Land Use Land Cover Dynamics on Stream Flow: A Case of Borkena Watershed, Awash Basin, Ethiopia

Abstract

AbstractIn the recent decade, the change in land use and land cover have changed the ecosystem services more rapidly than the previous similar periods. Land use land cover (LULC) change is the major factor that affect the watershed response. The main objective of this study was to assess the impact of land use and land cover change on the response of the Borkena watershed. The LULC change analysis was evaluated using supervised classification in ENVI software. The SWAT model was used to assess the impact of LULC change on streamflow for the period from 1996 to 2016. The study result revealed that the Borkena watershed experienced significant LULC changes from 1986 to 2016. Most of the grass land, cultivated land, and shrub land were changed to build-up and bare Land. The LULC map showed an increase of buildup area and bare land by 3.6% and 5.9%, respectively. There was a good agreement between simulated flow and observed data with a coefficient of determination (R2) and Nash-Sutcliff Efficiency (NSE) values of 0.81 and 0.79 in calibration, and 0.75 and 0.74 in validation periods, respectively. The evaluation of the SWAT hydrologic response due to the change in LULC showed that monthly streamflow was increased by 5.4 m3/s in the wet season and decreased by 0.5 m3/s in the dry season, and there was a significant effect (p < 0.05) of LULC change on watershed response. The changes in land use have resulted in changes in streamflow, due to the expansion of urbanization and land degradation.KeywordsLand use land coverStreamFlowSWAT modelAwash basinEthiopia