Predicting the daily streamflow of ungauged catchments in S.E. Australia by regionalising the parameters of a lumped conceptual rainfall-runoff model

Abstract

Deriving relationships between catchment-scale hydrologic response and landscape attributes allows the hydrologic response of an ungauged catchment to be predicted from its landscape attributes and climate. In this study, a lumped conceptual rainfall-runoff model was applied at a daily timestep to 16 small (less than 1 km 2) catchments in the Maroondah region of Victoria, Australia. The six parameters of this model can be used to characterise the daily streamflow of the catchments. It was demonstrated in Post and Jakeman (1996) [Post, D.A., Jakeman, A.J., 1996. Relationships between catchment attributes and hydrological response characteristics in small Australian mountain ash catchments. Hydrol. Processes 10: 877–892] that these six parameters are related to the landscape attributes of the catchments. In the current paper, these relationships are quantified and used to predict the daily streamflow of each catchment from its landscape attributes and daily rainfall and temperature, as if it were ungauged for streamflow. This predicted streamflow is then compared with the observed streamflow of the catchment. These relationships may also be used to predict the daily streamflow from other, similarly sized catchments in the Maroondah region. Some of the relationships between the model parameters and landscape attributes are well defined, while others are quite poor. As a result, the predictions of daily streamflow also vary in quality. Improvement of these results can be obtained through better understanding of the controls on hydrologic response.