Reproducing different types of changes in hydrological indicators with rainfall-runoff models

摘要

Hydrological indicators support analyses about the impact of climate and anthropogenic changes on riverine ecosystems. As these studies often rely on hydrological models for estimating the future value of the indicators,it is important to investigate how well,and under which conditions,we can replicate changes in the indicators. This study looks at these questions by investigating the performance that can be achieved depending on the objective function for calibrating the model,the direction of the change in the indicator,the magnitude of this change and the properties of the catchments. The results indicate that,in general,indicators describing the magnitude of discharge (monthly and annual) can be adequately estimated with hydrological models,but that there are difficulties when estimating the characteristics of flow pulses,flow reversals and timing variables. For some of these indicators,it is not even possible to correctly estimate the direction of large changes. The analysis showed further that these problems cannot be resolved by adjusting the calibrated parameters,but that the model structure is unsuitable for modelling these indicators.