This study mainly deals with evaluation of the climate change impact on Legedadi and Dire reservoirs which is found in north-east Awash River Basin, Ethiopia. Projection of the future climate variables is done by using Max Planck Institute for Meteorology – Earth System Model (MPI-ESM). In the present study, future rainfall MPI-ESM product corrected by using BFTV (Bias factor time variance).
The 1996-2016 was taken as baseline period against which comparison was made. A hydrological model, HEC-HMS was utilized to simulate Runoff in the study area. The performance of the model was assessed through calibration and validation process and resulted NSE=0.87 and PEV=7.5% during calibration and NSE=0.84 and PEV=7.85% during validation. The projected future climate variables has two future time series 2040s and 2080s, for both future time series an increasing trend evaporation from the open water surface of reservoirs when the projected average maximum and Minimum temperatures increase from the baseline period and precipitation shows a fluctuation event. Evaluation to the base and the future period average annual inflow volume shows an increase of 2.44% and decrease 0.99% at Dire reservoir and an increase of 5.15% and decrease 1.15% at Legedadi reservoir during 2040s and 2080s periods respectively.
In general analysis of the reservoirs with current and future climate change output indicates that the reliability and resilience of the reservoirs is sensitive to precipitation change than change in temperature on differing dimensionless vulnerability of the reservoirs doesn’t demonstration extraordinary difference for both the change in precipitation and temperature.