An Evaluation of Three Lumped Conceptual Rainfall-runoff Models at Catchment Scale

Lumped conceptual rainfall runoff models have been widely used in hydrology for many years. These models are usually able to describe most important processes in a catchment through a set of solvable equations. Thus, in many cases they are preferably over full physically-based models since they have such advantages: basic physicallybased and simplicity. However, many parameters of these models can not always be directly measured due to the fact that the conceptual models are lumped on catchment scales. Even though the model structure can be very detailed, the modelled results are possibly meaningless if the model parameters are poorly specified. The usefulness of the hydrological model relies on how well the model is calibrated. Three lumped conceptual rainfall-runoff models were presented and compared in this paper: NAM (DHI), FEH (UK), and TVM (a simplified model was developed by the author). If the NAM and TVM models are representative for continuous modelling, then the FEH model is event-based type. These three different models were applied to the Bradford catchment (UK) on a seasonal basis (summer and winter) with a time step of hourly or quarter hourly. The procedure of model calibration was presented. Model validation was performed together with statistical analysis. It has been shown in the study that overall the hydrological models represented in the paper give reasonable results in terms of accuracy. However, the selection of models for particular catchments should be based on data availability, project objective and model structure.