Assessment of hydro‑meteorological regimes of gidabo river basin under representative concentration pathway scenarios

Abstract

Climate change is a clear fact today, and its impact is seriously disrupting regional hydrometeorology. In this study, four dynamical downscaled regional climate model output variables with 0.44° spatial resolution were used to assess climate change's impact on hydrometeorology of the Gidabo river basin. Based on the climate model performance evaluation result RACMO2.2T model performed best in the basin and the outputs from this model were used as input data for the successfully validated HBV model to assess climate change impacts. The Mann Kendell trend test result shows an increasing trend in maximum temperature, minimum temperature, and potential evapotranspiration but the test result does not show any trend in precipitation. The climate projection result shows streamflow will decrease in the mid-future due to a significant decrease in precipitation and an increase of potential evapotranspiration in the basin. The drop-in stream flow can be up to 19.6% and 6.7%, under RCP 4.5 and RCP 8.5, respectively. This drop-in streamflow will have an impact on the river basin's prospective water resource availability. Therefore, it is recommended that adequate water-related adaptation strategies and choices must be planned and implemented throughout the river basin in the future.