Utilising mixed methods of defining joint probability of catchment and coastal flooding to increase certainty and utility of flood risk analysis
Peter J Coombes and Robert Swan presenting at the Hydrology and Water Resources Symposium HWRS2024 on Tuesday 19 November 2022 at 3:30 pm. We explore the utility of using mixed methods to understand the risk of joint catchment and coastal flooding.
Mixed methods were utilised to investigate the joint probability of catchment and coastal flooding in Melbourne near Port Phillip Bay in Victoria. We reveal consistency between Monte Carlo analysis of observed data, the Design Variable Method, statistical theory and relevant research publications in defining joint probability. It was found that 1% AEP peak flows in catchments coincides with a 100% AEP peak storm tides for the Moonee Ponds Creek catchment.
The Monte Carlo simulations provided robust information about joint probability of catchment and coastal processes near the coastal interface. The Design Variable Method provided similar and complementary information about joint probability that accounts for the hydraulics of infrastructure and waterways, and distance from the coast. Both methods can be employed to understand the impact of climate change on joint probability of coastal and catchment flooding. Mixed methods can overcome the limitations of the individual approaches.