Modelling Daily and Monthly Runoff in Urban Catchments

The ability of five modelling approaches to estimate daily and monthly runoff for three urban catchments in Canberra is assessed. The simulations indicate that a two-parameter impervious area model (runoff coefficient and rainfall/runoff threshold) combined with a four-parameter partial area runoff with baseflow model for the pervious area is sufficient to provide satisfactory estimates of monthly runoff in the urban catchments. However, using the moderately complex conceptual eight-parameter modified-HYDROLOG Model to simulate the pervious area gives better estimates of daily runoff in the urban catchments compared to the other approaches. Simpler methods like the Polynomial Equation and the SFB Model cannot simulate runoff satisfactorily. AQUALM, a model which has been frequently used for studies in urban catchments in south-east Australia, perform reasonably well compared to HYDROLOG and the partial area runoff model.