Integration of Monte Carlo Simulation Technique with URBS Model for Design Flood Estimation

The Monte Carlo simulation technique, based on the Joint Probability Approach, incorporates the probabilistic nature of key input variables such as rainfall intensity, duration, temporal pattern and initial loss, and their correlations in flood estimation. Previous application of the technique to three small gauged catchments in Victoria had shown promising results. However, the runoff routing was based on a single lumped storage placed at the catchment outlet and accordingly applicable to small catchments only. URBS is a RORB based distributed non-linear runoff routing model and one of several industry models used for design flood estimation for small to very large catchments. This paper shows that Monte Carlo simulation technique can be integrated with industry based models such as URBS. The integrated URBS-Monte Carlo Technique can be used to obtain more precise flood estimates for small to large catchments. The integrated model is now available in the window-based URBS model. It is expected that the integrated approach will have wider applications in flood studies, assessment of the hydrologic impacts of land use changes and hydrologic research.