IMPACT OF LAND USE AND LAND COVER CHANGE ON STREAM FLOW USING MIKE SHE: CASE STUDY OF SHAYA CATCHMENT, ETHIOPIA

Abstract

In this study, impacts of land use and land cover change on stream flow of the Shaya catchment in upper Genale Dawa sub-basin were assessed using MIKE SHE hydrological model. The study used different types of data including topography, soil, land use and land cover, climate, stream flow and field observation. Three years of data including 1987, 2000 and 2015 Landsat satellite image data were downloaded and processed using ERDAS Imagine 2014. Within this study area, settlement and agricultural area showed expansion. Bare land showed a continuous decrease within the studied periods. Forest land and the bushland were decreased in the first period and then showed little increment in second period compared to the base period (1987). Range land was increased and then decreased in first and second study periods, respectively. The MIKE SHE flow model performance was also evaluated using correlation coefficient (R), Nash-Sutcliffe coefficient (NSE) and Root Mean Square Error (RMSE) with values of R > 0.88, NSE > 0.78 and RMSE < 3.90 in all calibration and validation periods showing a very good agreement with the observed data. The impact of land use/cover change on mean annual stream flow was increased by 23.25% and 20.69% during calibration and validation for a study period of 1987 to 2015, respectively. Mean monthly stream flow increased during the wet season by 19.82% and decreased for the dry season by the value of 7.06% within the study period. The mean annual high stream flow values were decreased by 18.19% and then increased by 43.09% in the first and second periods, respectively. On the other hand, the mean annual low stream flow value was decreased by 0.1 % and 1.1% in the periods. Therefore, concerned bodies have to make appropriate control on the expansion of settlement and agricultural lands before it makes acute problems of the hydrologic balance of the catchment.