Continuous simulation of hydrologic systems requires the use of long sequences of high resolution climate data. Continuing advances in stochastic rainfall methods indicates that continuous simulation is likely to become a practical tool for hydrologic risk assessment. This study examines the case for adoption of continuous simulation. Two case studies are employed to compare the performance of continuous simulation and the Australian Rainfall and Runoff design storm approach. Both consider peak flow estimation in the context of volume-sensitive systems for detention basins and rainwater tanks. The case studies demonstrate the potential for large errors when using design storms to simulate the flood performance of volume-sensitive systems. It is significant that there does not appear to be an obvious way to “fudge” the design storm approach to make it reliable. Given the wide usage of detention and retention systems in urban stormwater management, one has to seriously question the fundamental assumptions that underpin Australian flood estimation practice. The case for adopting rigorous joint probability approaches such as continuous simulation is considerable
Is zero afflux the question or answer to better flooding outcomes?
Presentation by Peter J Coombes and Andrew Allan at HWRS 2022: Is zero afflux the real challenge or solution for better flood management? It is vitally important to establish science and legally based rules for fair administration of the objectives and exploration of options that respond to flood risks. Otherwise, there will be a substantial administrative burden for marginal benefit. Our professionals and agencies need to be prepared for a different and challenging future, and our methods need to be fit for purpose from a whole of society perspective.