COMPARISON OF 6 RAINFALL-RUNOFF MODELING APPROACHES

Six rainfall-runoff modelling approaches - simple polynomial equation, simple process equation (tanh equation), simple time-series equation (Tsykin equation), complex time-series model (IHACRES), simple conceptual model (SFB) and complex conceptual model (MODHYDROLOG) - are compared in this paper with the models used to simulate daily, monthly and annual flows in eight unregulated catchments. The complex conceptual model gives, by far, the best simulation of daily high and low flows, and can estimate adequately daily flows for the wetter catchments. It can provide satisfactory estimates of monthly and annual catchment yields in almost all catchments. However, the time-series approaches and the simple conceptual model can also provide adequate estimates of monthly and annual yields in the wetter catchments. As it is much easier to use these approaches than the complex conceptual model, the simpler methods may be used to estimate monthly and annual runoff in the wetter catchments.