Evaluations of Stream Flow Response to Land use and Land Cover Changes in Wabe Watershed, Omo-Gibe Basin, Ethiopia

Land Use and Land Cover Change (LU/LC) is one of the notable human induced worldwide changes. Hence, understanding the stream flow responses of a watershed to this dynamic change is becoming fundamental for water resources management planning. The study was conducted with the objective to analyses the impact of Land use and Land cover changes on stream flow response of Wabe watershed, in Omo-Gibe basin. Land use and land cover maps were developed using satellite image of Landsat5 TM 1988, Landsat7 ETM+ 2001 and Landsat8 OLI/TIRS 2018 through maximum likelihood algorithm of supervised classification using ERDAS Imagine 2014 and ArcGIS software for satellite image processing and map preparation. A physical based, semi-distributed hydrological model SWAT was used to simulate LU/LC change effects on the stream flow responses of watershed. During the study period the land use and land cover has changed due to natural and anthropogenic activity. The results depicted that there was an incessant expansion of agricultural land, built-up area and forest cover, on the other hand declining of agroforestry; grassland and woodland were happened during from the 1988 to 2018 periods. Due to the occurred LU/LC changes, the mean monthly stream flow were increased by 5.97m3/s for wet season and similarly the dry season flow showed increasing by 0.96m3/s during the study periods from 1988 up to 2018. Generally the result indicated that large changes of the stream flow in the watershed. Hence result notified an urgent intervention, so as to regulate the LU/LC change and to reduce its strong impacts on the stream flow of the Wabe watershed.