Efficacy of a storm-based Monte Carlo approach in modelling flood volumes

Design flood estimates are required to manage flood risks. Unlike peak flow estimates, flood volumes are often overlooked in many flood modelling studies. This can lead to gross errors in design flood volume estimates, which are crucial in storage sensitive catchments. The use of burst events (rather than entire storms) further exacerbates the issue. Therefore, in this study, a storm-based approach is employed within a Monte Carlo framework to simulate design flood hydrographs. The efficacy of the improved framework is tested on eight catchments along the east coast of New South Wales, Australia. Comparison of simulated and observed peak flow versus flood volume highlights the importance of considering both the peak flow and flood volume. Flood volume estimates are also compared to an at-site flood frequency analysis of flood volumes. Accuracy of the developed Monte Carlo framework was found to be dependent on event severity, and shows promise for further development and design applications.