Numerical and Physical Modelling of Major Hydraulic Structures in a Regional Shopping Centre in Sydney, Australia

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Brett Phillips, Stephen Yu, Nathan Guerry, Brett Miller

Wednesday 1 july 2015

8:45 - 9:00h at Central America (level 0)

Themes: (T) Extreme events, natural variability and climate change, (ST) Flood resilient cities and infrastructures

Parallel session: 8H. Water resources - Catchment

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Warringah Mall is a regional shopping centre located within the Brookvale Creek catchment in the Sydney’s northern suburbs. Studies in 2006, 2007 and 2008 identified that under existing conditions Warringah Mall is flooded by overland flows and overflows from Brookvale Creek. The 1D/2D modelling approach that was adopted to assess existing flooding problems and structural options including a major drainage augmentation through Warringah Mall is outlined. In response to the flooding problems which were identified and the risks to visitors and workers to the mall a major stormwater augmentation scheme within the Warringah Mall site was developed, assessed and approved with conditions by Warringah Council. One of the conditions of consent required a physical model study of the two large junction boxes to confirm the hydraulic losses which were assumed in the computer model studies and to provide advice on how the hydraulic losses in each junction box can be minimized. This physical model study is described. A comparison of the predicted and observed hydraulic losses and flood levels concluded that the current numerical 1D/2D model results appear to be conservative in comparison with the physical model results (which may be due to differences in adopted conduit roughness values in the numerical model and the roughness of the conduits in the physical model) and that the flood levels estimated by the numerical model are likely to be conservative.