Monte Carlo simulation for design flood estimation: a review of Australian practice

ABSTRACT

Rainfall-based design flood estimation methods in Australia traditionally follow the design event approach. However, the basic assumption of a probability neutral transformation in the design event approach has been widely criticised. For this reason, joint probability approaches (like Monte Carlo simulation) were proposed in the 1970s to account for the probabilistic nature of key inputs in rainfall–runoff modelling. However, these techniques were not seriously tested until the 1990s, when a simple Monte Carlo simulation technique was developed that used existing design data and models, for Australian hydrologic practice. This paper summarises the evolution of Monte Carlo simulation techniques for design flood estimation with a particular emphasis on Australian practice. It has been found that significant advancements have been made in the development and testing of Monte Carlo simulation in Australia; but, there is still a lack of commercial software hindering the routine application of holistic Monte Carlo simulation approaches.

KEYWORDS:

• Monte Carlo simulation
• joint probability approach
• design event approach
• design flood estimation
• floods
• rainfall
• runoff

Acknowledgements

The authors gratefully appreciate the detailed and valuable comments of Dr. Rory Nathan, whose contribution increased the overall quality of this paper. Thanks also to Mark Babister for his useful comments regarding ARR guidance.