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Abstract:
Understanding the projected changes in the mean flow, high flow, and the frequency ofhigh flow events remains a significant challenge due to uncertainty arising from globalclimate models (GCMs) and hydrological models. Moreover, the calibrationapproaches used for hydrological models can influence the climate change impactassessment. We use the combination of three hydrological models, four global climatemodels, and two RCPs (2.6 and 8.5) to analyze the projected changes in mean flow,high flow, and the frequency of high flow under the projected future climate in theGodavari River basins (GRB). The two evaluation approaches: namely a simpleapproach (TASK A) based on the calibration and validation at a single streamflowgauge station and a comprehensive approach (TASK B) based on multi-variable andmultisite calibration and validation and trend analysis were employed to evaluate thehydrological models. The differences between the projected changes in mean and highflows calculated using models after TASK A and TASK B were estimated. Our resultsshow that the differences can be about 10% in mean annual flow at intermediategauge stations. The comprehensively evaluated hydrological models project anincrease in mean flow, high flow, and the frequency of high flow at all four gaugestations in the GRB. The projected increases are higher under RCP 8.5 and in the Endcentury (2071-2100) in comparison to Near and Mid periods. Our results demonstratethe importance of the comprehensive evaluation of hydrological models for climatechange impacts assessment.
