AbstractRecent advances in hydrological impact studies points that the response of specific catchments to climate change scenario using a single model approach is questionable. Based on this hypothesis, this study was aimed at investigating the impact of climate change on the hydrological regime of river basins in three different climatic zones (China, Ethiopia and Norway) using WASMOD and HBV hydrological models. Specifically the objectives include (i) examining and comparing the hydrological response of different river basins to climate change scenarios, (ii) testing the sensitivity of WASMOD and HBV models, and (iii) testing the sensitivity of climate change scenarios in different climatic regions. The climate change response of the three basins (Didessa, Dongjiang and Elverum) were evaluated in terms of runoff, actual evapotranspiration and soil moisture storage change for incremental precipitation and temperature change scenarios using HBV and WAMOD models. The parameters of hydrological models were determined in the study catchment using current climatic inputs and observed river flows. The historical time series of climatic data was adjusted according to the climate change scenarios. The hydrological characteristics of the catchments under the adjusted climatic conditions were simulated using the calibrated hydrological model. Finally, comparisons of the model simulations of the current and possible future hydrological characteristics were performed. The calibration and validation results of WASMOD and HBV models show that both models can reproduce the runoff with acceptable accuracy for each basin. The findings of this study demonstrated that high sensitivity was observed for Didessa and Elverum to precipitation and temperature changes, respectively. However, Dongjiang was found less sensitive to both precipitation and temperature changes. In general, the results imply that there is limitation in moisture and temperature for Didessa and Elverum, respectively. The hydrological impact of climate
change resulted from synthetic scenario using the two models indicate that the sensitivity of catchments in response to different climate change scenario was different in different climatic regions. Thus, the result demonstrated a concern that hydrological impact of climate change analysis using single hydrological model may lead to unreliable conclusion. In this regard, conducting multi model analysis is one way to reduce such uncertainty. Finally, we recommend further research in this area in order to exhaustively explore hydrological impact of climate change in different regions.