Impact of land use/land cover change on stream flow in the Shaya catchment of Ethiopia using the MIKE SHE model

Abstract

The impact of land use/land cover (LULC) change on the stream flow of the Shaya catchment was assessed by employing the MIKE SHE hydrological model. The digital elevation model, soil, LULC, climate, and stream flow data were used as model inputs. The LULC was analyzed from different years of satellite imageries using ERDAS IMAGINE software package and its accuracy was verified following the standard procedures. Trend and shift detection analysis were also conducted to study the effect of rainfall on stream flow using the Mann–Kendall (MK) and Pettit tests, respectively. The result showed that there is a significant expansion of settlement and agricultural area, while there was a decrease of bare land, forest, and bush land in the catchment. In contrary, rangeland was increased from the year 1987 to 2000 and then decreased from 2000 to 2015. The performance of the MIKE SHE hydrological model was very good both during model calibration and validation periods. It has been observed that rainfall did not show any significant trends and shifts, but the stream flow was increased significantly in the two decades. In this study, the effects of LULC change on the stream flow in the study area have been distinguished: the mean monthly stream flow was increased during the wet season, while it was decreased during the dry season. Therefore, we recommend concerned bodies to monitor and take appropriate control of the LULC changes, especially settlement and deforestation, before it makes acute problems of the hydrologic imbalance in the catchment.